Searches identified published reports of 6 trials. Information from 599/1909 patients was not published; trials with 846/1909 patients were published in a defunct journal. Greater methodological information in CSRs contributed to lesser risk of bias than published trials. Numbers needed to treat (NNT) from CSRs for all six postoperative trials for at least 50% of maximum pain relief over 6 h were 2.2  and 2.1 (1.8–2.4) for 50 and 100 mg diclofenac potassium, respectively. A Cochrane review of published trial data reported NNTs of 2.1 and 1.9, and one comprehensive analysis reported NNTs of 2.2 and 2.1, respectively. All analyses had similar results for patients remedicating within 8 h. No data from dysmenorrhoea CSRs appeared in a Cochrane review. CSRs provide useful information and increase confidence. Stable efficacy estimates with standard study designs reduce the need for updating reviews.We compared the efficacy of diclofenac potassium in unpublished clinical study reports (CSRs) and published reports to examine publication bias, industry bias, and comprehensiveness. Novartis provided CSRs of randomised double-blind trials of diclofenac potassium involving postoperative patients following third molar extraction (3 trials,  Systematic reviews are meant to include all relevant information, and considerable effort goes into ensuring comprehensiveness. At the same time, researchers need to be alert to the dangers of including duplicate reports of trial(s) as this can inflate treatment effects . There iNonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and diclofenac have been available for 40 years or more. Fast-acting oral formulations produce more rapid absorption and higher, earlier, concentrations in blood, giving greater efficacy for the same dose –14. ReceBoth developments are relevant to diclofenac, which is available in two salt formulations. Diclofenac sodium is usually available as enteric-coated tablets that resist dissolution in the low pH of the gastric environment, with release of drug in the duodenum . This teWe originally aimed to perform a systematic review of CSRs of diclofenac potassium using what was thought to be unpublished material and to compare the results of diclofenac potassium efficacy from unpublished CSRs with that from published reports to examine potential effects of publication bias, industry bias, and comprehensiveness. In doing so, we discovered some unusual, and we think new, insights relating to understanding how comprehensiveness impacts on estimates of efficacy.This study developed out of a review of the cardiovascular safety of NSAIDs triggered by several regulatory authorities in 2013-2014. Novartis prepared a comprehensive list of all clinical trials of diclofenac as a part of a benefit-risk evaluation of the compound. Initial research based on that comprehensive list involved analyses relating to diclofenac  in chronic pain , 19. OneThe comprehensive list also identified a number of studies of diclofenac potassium in acute pain, performed in the late 1980s and early 1990s. At the time, these were thought to be unpublished; a project plan was developed by RAM for a review of these “unpublished” trials based on the clinical study reports, as individual patient-level data were not available. We compared study characteristics of CSRs with published reports as part of due diligence to protect against including duplicated data, and so the direction of the study changed to examining the impact of available data on estimates of efficacy.Randomised, double-blind trials of diclofenac potassium in acute postoperative pain or dysmenorrhoea sponsored by Novartis Pharma AG or its predecessor companies were retrieved from the Novartis comprehensive database. We sought clinical study reports or  study data available at the level of the individual patient. Trials had to have been concluded by the end of 2013 to be eligible, as analysis and compilation of a CSR takes time.Electronic searches were carried out for systematic reviews and meta-analyses of diclofenac potassium in acute postoperative pain and dysmenorrhoea, using PubMed with the “Review” filter both on and off. The date of the last electronic search was December 2015. There was no restriction as to language or date in our searches.We also sought relevant published randomised trials identified from the Cochrane reviews of diclofenac in acute postoperative pain  and dysmWe included randomised double-blind trials of single dose oral diclofenac potassium compared with placebo for the treatment of moderate to severe postoperative pain or dysmenorrhoea in adults, with at least 10 participants randomly allocated to each treatment group. Multiple-dose studies were included if appropriate data from the first dose were available; crossover studies were included if information from the first arm was presented separately. Postpartum pain studies were included if the pain investigated was due to episiotomy or caesarean section irrespective of the presence of uterine cramps; studies investigating pain due to uterine cramps alone were not included. Participants had to be adults  with established postoperative pain of moderate to severe intensity following day surgery or inpatient surgery, or moderate or severe pain from dysmenorrhoea. A visual analogue scale (VAS) pain intensity of greater than 30 mm was considered to be pain of at least moderate intensity .We excluded case reports and clinical observations, studies of experimental pain, studies where pain relief was assessed only by clinician, nurse, or other carers and not reported by the patient themselves, studies of less than four hours' duration, or studies that failed to present data over four to six hours after dose.Any systematic review or meta-analysis was eligible for inclusion. For the Cochrane reviews, only the most recently updated version was selected.We assessed the potential risk of bias in all the included randomised trials. The Oxford Quality Score was the basis for study inclusion, limiting inclusion to studies that were randomised and double-blind as a minimum .Cochrane Handbook for Systematic Reviews of Interventions, resolving any disagreements by discussion [Random sequence generation (checking for possible selection bias): we assessed the method used to generate the allocation sequence as low risk of bias  and unclear risk of bias (method used to generate sequence not clearly stated). We excluded studies using a nonrandom process, which were therefore at high risk of bias .Allocation concealment (checking for possible selection bias): we assessed the method used to conceal allocation of the intervention as low risk of bias  and unclear risk of bias (method not clearly stated). We excluded studies that did not conceal allocation, which were therefore at high risk of bias (open list).Blinding of participants, study personnel, and outcome assessment (checking for possible performance and detection bias): we assessed the methods used to blind study participants and personnel from knowledge of which intervention a participant received as low risk of bias  and unclear risk of bias (study stated that it was blinded but did not provide an adequate description of how blinding was achieved). We excluded studies that were not double-blind and therefore at high risk of bias.Size : small studies have been shown to overestimate treatment effects, probably because the conduct of small studies is more likely to be less rigorous, allowing critical criteria to be compromised –27. We cWe also completed a “Risk of bias” table using methods adapted from Cochrane. The authors independently assessed risk of bias for each study using the criteria outlined in the scussion . The folA potential bias in trials involves missing data and use of imputation using last observation carried forward when a patient requests rescue medication. This does not affect results for up to six hours after taking study medication in acute pain trials , 28.The primary pain outcome was that of participants achieving at least 50% pain relief over four to six hours after study drug administration. This outcome has been used for over 20 years, validated several times as sensitively discriminating between analgesics of different efficacy, and is of value in postoperative pain , 29 and For each study, we converted the mean total pain relief (TOTPAR) and summed pain intensity difference (SPID), visual analogue scale (VAS) TOTPAR, or VAS SPID values for the active and placebo groups to %maxTOTPAR or %maxSPID by division by the calculated maximum value . We thenFive-point categorical pain relief (PR) scales with comparable wording to “none, slight, moderate, good, or complete”Four-point categorical pain intensity (PI) scales with comparable wording to “none, mild, moderate, or severe”VAS for pain reliefVAS for pain intensityWe accepted the following pain measures for the calculation of TOTPAR or SPID, in order of priority:Patients reporting a global evaluation as “very good” or “excellent” on a five-point categorical global scale with the wording “poor, fair, good, very good, or excellent”Patients using rescue medication within a particular time Patients with any adverse event, any serious adverse event (as reported in the study), and withdrawal due to an adverse eventOther outcomes looked for were as follows:For efficacy analyses, we used a number of participants in each treatment group who were randomised, received medication, and provided at least one postbaseline assessment. For safety analyses, we used a number of participants randomised to each treatment group who took the study medication. Pooled analyses were performed by pain condition and diclofenac dose using data in the CSRs only, for comparison with results from the Cochrane reviews. We also performed a pooled analysis for all available diclofenac data in all postoperative studies for 50 mg and 100 mg doses of diclofenac potassium and irrespective of formulation, for both data from the CSRs and for all available identified studies. We used CSRs rather than published trial data when both were available.When significantly fewer adverse outcomes occurred with treatment than with control (placebo or active), we used the term the number needed to treat to prevent one harmful event (NNTp).When significantly more adverse outcomes occurred with treatment compared with control (placebo or active), we used the term the number needed to harm or cause one additional harmful event (NNH).Risk ratio  was used to establish statistical difference, and numbers needed to treat for one additional beneficial outcome (NNT) and pooled percentages as absolute measures of benefit or harm. The following terms were used to describe adverse outcomes in terms of harm or prevention of harm:The plan was to analyse data by type of clinical condition . Previous research suggested that the type of surgery made no difference in NNT estimates for acute postoperative pain , and thiz test [Where there were sufficient data , we calz test .The Novartis database included eight randomised trials  were either unpublished or published in journals not covered by PubMed.Pairwise comparisons for the risk of bias evaluations are in Supplementary AppendixSupplementary Appendix Information was available from 509 patients, with detailed results for at least 50% maximum pain relief, global evaluation of “very good or excellent” and patients remedicating within 8 hours . All thrNNT values for diclofenac potassium 50 and 100 mg were low, at about 2, for the two efficacy results of at least 50% maximum pain relief and global evaluation of “very good or excellent,” with somewhat better results for the higher dose, although the difference was not significant. Fewer patients remedicated with active treatments than with placebo, with the best results obtained for diclofenac potassium 100 mg.Diclofenac potassium 100 mg was significantly better than aspirin 650 mg on three efficacy measures, but 50 mg was not . The timInformation was available from 685 patients, with results for at least 50% maximum pain relief, global evaluation of “very good or excellent,” and patients remedicating within 8 hours . Both trNNT values for diclofenac potassium 50 mg and 100 mg were low, at about 2.2 to 2.5, for the two efficacy results of at least 50% maximum pain relief and global evaluation of “very good or excellent,” with somewhat better results for the lower dose, although the difference was not significant. Fewer patients remedicated with active treatments than with placebo, with the best results for diclofenac potassium 100 mg.Diclofenac potassium 50 mg was significantly better than aspirin 650 mg on the three efficacy measures, and 100 mg was significantly better than aspirin 650 mg for global evaluation and remedication . The timInformation was available from 711 women, but trials included data from two menstrual cycles in almost all of the women. Both trials used placebo and naproxen sodium 550 mg as a common active comparator.Because there were no washout issues, there was a fresh randomisation for each cycle; as results of first and second cycle studies were not different, these have been combined in this analysis. Results for the first dose of analgesic per cycle have been used in this report. The comparisons of active treatments with placebo are shown in NNT values for diclofenac potassium 50 mg and 100 mg were modest, at about 3.0 to 4.0, for the two efficacy results of at least 50% maximum pain relief and global evaluation of “very good or excellent,” with somewhat better results for the higher dose, though the difference was not significant. Fewer patients remedicated with active treatments than with placebo, with best results for 100 mg.Neither dose of diclofenac potassium was significantly better than naproxen sodium 550 mg on any efficacy measure . RemedicNone of the comparisons for adverse events found any difference between active drug and placebo for the number of patients experiencing an adverse event after a single dose of study medication Tables –3. EvenNo serious adverse events were reported in the CSR or published report of any postoperative trial. In the dysmenorrhoea trials, one patient in a naproxen sodium group had a diagnosis of breast cancer (CSR 10). CSR 11 reported several serious events. In diclofenac groups, these were one probable and one possible seizure, and one each of dulled sensorium, erosive gastritis, increased bilirubin, ureteral calculus, and appendicitis. In the naproxen group, there was one death in a fire and one case of Bell's palsy.We updated the calculations of at least 50% maximum pain relief, patients remedicating within 8 hours, and those who experienced at least one adverse event for all available postoperative data. For the 50 mg and 100 mg dose, this analysis used data from seven trials with diclofenac potassium , 43–45 tThis study examined CSRs of eight randomised trials (1909 patients), investigating the effects of diclofenac potassium in acute postoperative pain after dental or gynaecological surgery and dysmenorrhoea. Analysis of CSRs for postoperative pain agreed with analyses of extant systematic reviews, demonstrating that diclofenac potassium was an effective analgesic using outcomes of at least 50% of maximum pain relief, global evaluation of “very good or excellent,” and the need for remedication for inadequate pain relief within 8 hours. NNT values were low and comparable with analgesics known to be very effective in these conditions. There was no clinically important difference in efficacy between 50 mg and 100 mg doses of diclofenac potassium; NNTs for 50 mg were almost identical to those for 100 mg .Although the majority of data from these CSRs had been published in peer-reviewed journals, data from three had not; this included data from 547 patients in fully completed trials and 56 from a discontinued trial . Unfortunately, much of the published information was in an obscure journal, now discontinued, and not available in the most-used search engine of PubMed, but only through specialist registers or through EMBASE, which is less frequently used for casual searches because it often requires subscription. None of these trials would be found by casual, or perhaps even quite informed searching of electronic databases, meaning that around 76% of available evidence from these CSRs would not be easily available. The fact that the Cochrane reviews in acute pain  and dysmThe quality of the evidence available in the CSRs was good. All of the trials were properly randomised and blinded and scored a maximum of 5/5 on the Oxford Quality Score. Risk of bias assessment typically conducted in the Cochrane reviews showed a general absence of risk, with the exception of small trial size; small acute pain trials like these are susceptible to random chance effects .The longer, more detailed CSRs (average 181 pages per report compared with 13 published pages on average) contained more information relevant to assessment of study quality and risk of bias than did published versions, which omitted important methodological information. Assessment of published evidence was downgraded because of these omissions and judged to be at a potentially higher risk of bias than was actually the case. Compared with published versions of the trials, the CSRs provided additional important methodological insights and reassurance about lower risks of bias.It is worth noting, however, that the trial funding source or statements of conflicts of interest potentially influence readers more than the actual quality of the evidence , 54. WhiFor postoperative pain, an updated Cochrane review of diclofenac for acute postoperative pain is the most relevant published analysis , and theCorresponding results for CSR analyses and larger systematic reviews were also seen for aspirin. For the six postoperative CSRs in this review, the NNT for at least 50% maxTOTPAR for aspirin 650 mg compared with placebo, with 543 patients in the comparison, was 3.2 (2.6 to 4.1). This is not statistically different from the NNT from a Cochrane review for aspirin 600/650 mg reporting 4.2 (3.9 to 4.8) based on 4630 patients from 60 studies in the comparison with placebo . The NNTNeither the Cochrane review nor this review found any difference between active drug and placebo in terms of patients reporting adverse events after a single dose. For both diclofenac potassium at 50 mg and 100 mg doses and the comparator, aspirin 650 mg, the results from clinical study reports provide essentially the same results for efficacy and for adverse event reporting.A Cochrane review on NSAIDs for dysmenorrhoea was able to analyse data from three small studies of 140 women taking diclofenac for dysmenorrhoea, with no mention of the formulation used (one was probably a suppository), and reporting only odds ratios . This reNaproxen sodium 550 mg was reported to have an NNT of 3.1 (2.4 to 4.4) for the outcome of at least 50% pain relief over six hours in a pooled analysis of two trials of 359 menstrual cycles in 231 women . This coFor postoperative pain and especially for dysmenorrhoea, review of clinical study reports of diclofenac potassium has produced substantial additional information to that available in current Cochrane reviews, the only published systematic reviews we found relevant to diclofenac potassium in these painful conditions. Clinical study reports provided more detailed descriptions of methods used in trials and showed that the trials were of higher quality and with lower risk of bias than those reported in published accounts of the same trials. These findings indicate that the clinical study reports provide a better appreciation of efficacy and harm than the published reports in acute painful conditions. This has been shown before for acute , 14, 28 Where quantitative comparison was possible for postoperative conditions, the main efficacy results from review of these CSRs provided very similar estimates to the published systematic reviews, with no tendency to under- or overestimation. Once a minimum amount of good quality clinical trial data are available, then there is little tendency for the effect size to change when similar trials are performed. This has implications for the need to continually update some systematic reviews, at least for single dose studies in acute pain that have standard and validated methods . It alsoWhere there are limited data on particular formulations for analgesics used to treat acute pain, as for diclofenac potassium, the use of CSRs provided more data and allowed calculation of outcomes of known value . The val


Background. Treatment of intractable pain due to chemotherapy induced peripheral neuropathy (CIPN) is a challenge. Intravenous (iv) lidocaine has shown to be a treatment option for neuropathic pain of different etiologies. Methods. Lidocaine (1.5 mg/kg in 10 minutes followed by 1.5 mg/kg/h over 5 hours) was administered in nine patients with CIPN, and analgesic effect was evaluated during infusion and after discharge. The immediate effect of lidocaine on pressure pain thresholds (PPT) and the extent of the stocking and glove distribution of sensory abnormalities (cold and pinprick) were assessed. Results. Lidocaine had a significant direct analgesic effect in 8 out of 9 patients (P = 0.01) with a pain intensity difference of >30%. Pain reduction persisted in 5 patients for an average of 23 days. Lidocaine did not influence mean PPT, but there was a tendency that the extent of sensory abnormalities decreased after lidocaine. Conclusion. Iv lidocaine has direct analgesic effect in CIPN with a moderate long-term effect and seems to influence the area of cold and pinprick perception. Additional research is needed, using a control group and larger sample sizes to confirm these results.  Chemotherapy induced peripheral neuropathy (CIPN) is a clinically relevant side effect of various chemotherapeutic drugs that prevents an optimal treatment regimen in a significant proportion of patients , 2. AlthClinically, CIPN mainly manifests as a sensory peripheral neuropathy, although motor and autonomic nerve fibers may also be involved , 4. The 2), liver disease , hypokalemia, a known allergy for local anesthetics of the amide-type, diabetes mellitus or other known peripheral neuropathic disease, and pregnancy or lactation. Concomitant use of other analgesics drugs at the moment of inclusion was continued if necessary, without dosage modifications. Demographic characteristics like age, gender, medical history, previous analgesics usage, and Hospital Anxiety and Depression Scale (HADS) were collected. Patients completed the National Cancer Institute-Common Toxicity Criteria (NCI-CTC) questionnaire before treatment with lidocaine. The NCI-CTC questionnaire is used to determine the grade of neuropathy, ranging from 0 to 4, where 0 corresponds to no neuropathic symptoms and 4 to the most severe neuropathic symptoms ) was found. For limbs and infusion separately, the pinprick detection level was always more cranial as the cold detection level; however, in these subgroups with less observations the difference is not always statistically significant (P varies between 0.018 and 0.625). In 1 patient no changes in cold or pinprick sensation were observed.Although individual patients could have an asymmetrical distribution of their stocking and glove distribution, no statistically significant difference was found between left and right side for the distribution of sensory changes for pinprick and cold in the whole group. Combining both limbs before and after lidocaine infusion, the cold detection level was significantly more caudal as the pinprick detection level .In 4 patients the area of abnormality in cold perception decreased after infusion. Three patients reported an increase in area in the upper or lower extremity after infusion. One patient showed a combination of positive change in one leg and a negative change in the other leg. The area of cold perception decreased when combining the limbs in all patients .In 4 patients the area of abnormal pinprick sensation in the upper or lower extremities decreased after infusion; in 1 patient it increased in both upper and lower extremities. Three patients showed a combination of both increase in one area and decrease in another. The area of abnormal pinprick sensation decreased when combining the limbs in all patients (A single infusion of lidocaine decreased pain in 8 out of 9 patients with CIPN, which was correlated with duration of iv lidocaine infusion. The long-term analgesic effect of lidocaine was moderate with a mean duration of 23 days. Lidocaine had no effect on pain sensitivity measured by PPT. The distribution of sensory abnormalities was influenced by lidocaine.There have been other studies that assessed the effect of iv lidocaine on neuropathic pain, but to our knowledge no study has specifically investigated the effect of lidocaine in CIPN. A Cochrane review that included 30 RCTs showed that iv lidocaine and its oral analogues, mexiletine and tocainide, reduce neuropathic pain . This rePPT is increasingly used to compare pain sensitivity before and after treatment , 32. No δ and C-fibers sensitive to innocuous cooling and cold-sensitive nociceptors. The perception of pinprick pain intensity is related to activity in A-δ fiber nociceptors [Spread of sensory abnormalities showed a marked variance between patients; however the mean affected area for cold detection had a tendency to be smaller than for pinprick. Cooling the skin to 4°C activates A-iceptors . Krøigåriceptors . These rThe effect of lidocaine on the distribution of sensory abnormalities showed unexpected results, with an increase of sensory abnormalities in some and a decrease in other patients. Although these changes were not statistically significant, it is interesting that a pharmacological agent can influence and maybe decrease sensory abnormalities. These results could provide a basis for further research on developing treatments, including specific sodium channel blockers, which reduce or even treat sensory disturbances in polyneuropathy.CIPN is known to be a common dose limiting side effect of chemotherapeutic agents like taxanes, vinca alkaloids, and platinum compounds , 2. PropIn this study, patients with various types of malignancies were included, who were also treated with different chemotherapeutic agents, which may have resulted in heterogeneity of their sensory profiles. From these data no conclusions can be drawn which sensory abnormalities can be seen in CIPN caused by a specific type of chemotherapy or which responds best to lidocaine treatment. Since several trials indicate that sensory phenotyping can predict drug responsiveness , 38, a lIv lidocaine, an old-school drug, significantly reduced intractable pain in patients with CIPN for an average of 23 days in our study and there was a tendency for a decreased extent of sensory abnormalities. Our results are therefore promising and show a potential role for iv lidocaine in patients with CIPN, when standard treatment algorithm for neuropathic pain fails . This mi


Purpose. Failed back surgery syndrome is a chronic pain condition requiring rapid, effective, and efficient management. This study evaluates the effect of adding dexmedetomidine to lumbar epidural steroids in patients with failed back surgery syndrome. Methods. Fifty patients suffering from failed back surgery syndrome were randomly assigned to one of two groups, receiving an epidural injection of 20 mL of either a mixture of betamethasone (14 mg) and bupivacaine 0.5 mg (group C) or a mixture of betamethasone (14 mg), bupivacaine 0.5 mg, and dexmedetomidine (0.5 μg/kg) (group D) adjusted to the volume with normal saline. The effect was evaluated using visual analogue scale (VAS), analgesic requirement, and Oswestry disability index 2 weeks, 4 weeks, 8 weeks, and 12 weeks after injection. Results. VAS and ibuprofen consumption showed a significant reduction in group D. The Oswestry disability index was significantly improved in group D. There were no records of hypotension, bradycardia, sedation, or hypoxemia in both groups. Conclusion. The present study demonstrated potential safe and effective usage of adding dexmedetomidine to epidural steroid to control pain in patients with failed back surgery syndrome. The addomy pain .We designed the present double-blind and randomized study using dexmedetomidine as an adjunct to epidural steroids to examine the effect of dexmedetomidine on pain, amount of analgesics, and activity of patients suffering FBSS.http://www.pactr.org/). Patients were excluded if they suffered from a sacroiliac joint disease, facet joint arthritis revealed by magnetic resonant imaging, severe cardiopulmonary disease, uncontrolled diabetes, morbid obesity (body mass index ≥ 40 Kg/m2), addiction, infection, and coagulation disorders and if patients were on opioid medications for pain management before or during the study period. After explaining study protocol and visual analogue score (VAS) graduated from zero (no pain) to 10 cm (worst pain) to the patients, they were randomly assigned by using closed envelope technique to one of two groups. Group C (control group) received an epidural injection of 20 mL of a mixture of betamethasone (14 mg) and bupivacaine (0.5 mg) adjusted to the volume with normal saline. Group D (dexmedetomidine group) received an epidural injection of 20 mL of a mixture of betamethasone (14 mg), bupivacaine (0.5 mg), and dexmedetomidine (0.5 μg/kg) adjusted to the volume with normal saline. The epidural injection was administered with the patient in a lateral recumbent position, while his/her neck, pelvis, and knees were bent. The skin and subcutaneous tissues were anesthetized by injecting 1-2 mL of lidocaine 2% between L2 and L5 spinous processes (identified by fluoroscopy) and a 20-gauge Touhy needle was inserted approximately 2-3 cm so that the needle went into the interspinal ligament. Then, a syringe containing air was attached to the needle and the needle was inserted slowly, 1-2 mm at a time until no resistance was felt. Afterward, 2 mL of nonionic radiocontrast was injected into the location of the needle to identify that the contrast was diffusing in the shape of thin strings toward the top of the image. When the needle was identified in the epidural space through the interspinal ligament approach method, the study drugs were injected. The patients were then transferred to the Peri-Anesthesia Care Unit (PACU) for monitoring vital signs, pain levels, and possible neurological and other adverse events for 60–90 minutes. They were then discharged home (4 hours after the procedure) in the care of a responsible adult and advised not to drive for 24 hours. The pain intensity was evaluated by visual analogue scale scores. As per the patient's request to analgesia when VAS was greater than or equal to 4, oral 200 mg ibuprofen tablet was given and the total amount of nonsteroidal anti-inflammatory drug (NSAID) per week was calculated and recorded. The effects of the procedures were evaluated by measuring the visual analogue scale (VAS) and Oswestry disability index (ODI) before the procedures then 2 weeks, 4 weeks, 8 weeks, and 12 weeks after the procedure. The incidence of complications was recorded, including the occurrence of hypotension (systolic blood pressure < 90 mmHg), bradycardia (pulse rate < 50/minute), extensive sedation , or hypoxemia (oxygen saturation below 90%). In a case of marked hypotension, rapid infusion of 500 mL crystalloids and ephedrine 5 mg was given, and heart rate less than 50 beats/min was treated with 0.3 mg atropine.After obtaining approval from the institutional ethics committee and written informed consent, 50 patients, 40–70 years old of both sexes, ASA physical status I–III, suffering from FBSS were included in this prospective, double-blind, randomized controlled study at the Menoufiya University outpatient pain clinic. The study protocol was registered with the Pan-African Clinical Trial Registry . Nonparametric data was expressed as a number of patients or median (interquartile range). Determining the extent of a single observed series of proportions and difference from a theoretical or expected distribution was done using the Chi-square test (sex) and Mann-Whitney U test (VAS). P value < 0.05 was considered statistically significant.The collected data were analyzed by Statistical Package for Social Science (SPSS) version 16. Parametric data were expressed as mean ± SD. The comparison of the mean ± SD of two groups was done using the paired and unpaired Student's The study was performed on 50 patients randomly divided into 2 equal groups. Patients characteristics were similar in the 2 groups regarding the demographic data  . For VASFBSS is a major concern in pain therapy. Although the exact incidence remains unknown, it is estimated to be as high as 60% of patients who have had back surgeries . In thisα2 adrenergic receptor binding, it is widely used as a systemic analgesic adjuvant [α2-AR agonists is mostly mediated at the spinal level, neuraxial administration was chosen for the dexmedetomidine adjuvant. Moreover, its high lipophilicity allows for rapid absorption into the cerebrospinal fluid and binding to the spinal cord α2-AR [Due to the fact that dexmedetomidine has a high selectivity to adjuvant . Furtheradjuvant , 12. Sinrd α2-AR .μg/kg administered either epidurally [μg/kg added to epidural betamethasone due to short term follow-up of the patients as they were discharged home 4 hours after the procedure.Many studies have used dexmedetomidine safely in a dose of 1-2 idurally –16 or caidurally , 17–19 fIn the current study, we evaluated the effectiveness of the analgesic effect of long-acting steroid preparation, betamethasone, mixed with dexmedetomidine. The primary efficacy outcome parameters were a reduction in the intensity of pain after treatment with the epidural injection. Also, NSAID doses were significantly reduced when dexmedetomidine was added to the epidural steroid. Life style was improved in dexmedetomidine group as reported by the significant decrease in SDI. These results are consistent with the results of other studies using dexmedetomidine as an adjunct in the treatment of chronic pain syndromes in human –22, suchα2-AR agonist clonidine administered epidurally to control chronic pain. Lavand'homme and De Kock found that epidural or intrathecal clonidine added to local anesthetic may also prevent the development of chronic postsurgical pain and hyperalgesia after major abdominal surgery [The same results of the present study were found by other studies performed by using another  surgery . Laurett surgery . Moreove surgery  reportedNo significant adverse effects in the form of hypotension, bradycardia, sedation, or hypoxemia occurred and did not affect the time of hospital discharge of patients. All patients were discharged after 4 hours of the injection.In conclusion, the present study demonstrated a potential safe and effective usage of adding dexmedetomidine to epidural steroid to control pain in patient with failed back surgery syndrome, as reflected by the significant reduction of pain intensity, reduction of NSID doses, and better quality of life with no significant adverse effects.


The purpose of this study was to assess the psychometric properties of a Swedish version of the Posttraumatic Diagnostic Scale (PDS); to investigate the prevalence of traumatic experiences, trauma types, and posttraumatic stress disorder (PTSD) in a sample of patients seeking treatment for chronic pain; and to examine how indices of pain-related functioning vary with a history of traumatic exposure and PTSD diagnostic status.Participants were 463 consecutive patients with chronic pain referred for assessment at the Pain Rehabilitation Unit at Skåne University Hospital.The translated version of the PDS demonstrated high levels of internal consistency and a factor structure similar to that reported in previous validation studies using samples identified because of trauma exposure (not chronic pain), both of which provide preliminary support for the validity of this translated version. Based on their responses to the PDS, most patients (71.8%) reported one or more traumatic events with 28.9% fulfilling criteria for a current PTSD diagnosis. The patients with PTSD also reported significantly higher levels of pain interference, kinesiophobia, anxiety, and depression and significantly lower levels of life control, compared to patients exposed to trauma and not fulfilling criteria for PTSD and patients with no history of traumatic exposure.Consistent with previous research, a significant proportion of patients seeking treatment for chronic pain reported a history of traumatic exposure and nearly one third of these met current criteria for PTSD according to a standardized self-report measure. The presence of PTSD was associated with multiple indictors of poorer functioning and greater treatment need and provides further evidence that routine screening of chronic pain patients for PTSD is warranted. Self-report measures like the PDS appear to be valid for use in chronic pain samples and offer a relative low-cost method for screening for PTSD. Chronic pain is often defined as any pain that lasts more than 3 months , and chrChronic pain patients with PTSD have been found to score more highly on measures of emotional distress, pain intensity, and pain disability compared to those with traumatic exposure without PTSD and those without traumatic exposure . The preThe aims of this study are threefold. The first aim is to assess the psychometric properties of a Swedish version of the PDS. First, we investigate whether the PDS possesses acceptable internal consistency and construct validity. To assess the latter, we examine the correlations between the PDS and measures assessing convergent constructs. For reasons relating to measurement burden on a clinical group, another trauma/PTSD measure was not administered. Instead, we examine the relationship between scores on the PDS and measures of anxiety, depression, and kinesiophobia (fear of movement that might exacerbate pain), which are used as part of the standard clinical assessment of adults seeking treatment for chronic pain at the unit where the present data were collected. Consistent with previous literature , 35, 37,As a further examination of the validity of this Swedish translation of the PDS, we undertake confirmatory factor analyses to assess the structural validity of the PDS. Several studies have investigated the factor structure of the symptom portion (part 3) of the PDS and concluded that the observed factors do not reliably correspond to the three symptom clusters described in DSM-IV, i.e., re-experiencing, avoidance/numbing, and hyperarousal , 36, 38.The second aim is to investigate the prevalence of traumatic experiences, trauma types, and PTSD in a sample of patients seeking treatment for chronic pain. Based on previous research , 16, we Participants were 463 adults with chronic pain consecutively referred for assessment at the Pain Rehabilitation Unit at Skåne University between August 2013 and February 2015. This government-funded unit based within Swedish national health services is the largest specialist center for the assessment and treatment of chronic pain in Region Skåne, the southernmost region of Sweden with 1.26 million inhabitants . All patients gave written informed consent prior to their data being used in the study, and the study was approved by the Regional Ethical Review Board (2013/381).The sample consisted of 334 women (72.1%) and 129 men (27.9%) between 18 and 67 years of age . The majority (77.4%) were born in Sweden or another Nordic country, and approximately half (53.3%) were currently in work or further education. More than half had upper secondary school as their highest level of education (54.4%), with 14.2% having completed secondary school and 27.1% having studied at or completed university. The median time since pain onset was 5.0 years (range = 29.3 years), and the median number of pain locations was 13.0 (range = 36 locations). Usual pain intensity rated on a 0–10 scale was 7.5 (SD = 1.5). The most frequently reported primary diagnoses were fibromyalgia (28.4%), cervicocranial syndrome (9.6%), cervicobrachial syndrome (8.7%), lumbago (8.7%), and myalgia (7.0%). The sociodemographic and clinical characteristics of this sample were similar to the clinic’s referrals as a whole and to patients seeking treatment for chronic pain at other regional specialist pain units across Sweden .Internationally recommended guidelines were followed when translating the PDS for the purposes of this study . First, Prior to the first face-to-face assessment at the chronic pain unit, a range of self-report measures (described below) were sent to the patients’ homes to be completed and brought to their first full clinical assessment . At the same time, the patients also provided information relating to age, gender, education, country of birth, work status, pain sites, and pain duration.α = .92), satisfactory test-retest coefficients (range = .77 to .85), and good convergent validity in relation to PTSD diagnosis assessed by standardized clinical interview. The scale has also demonstrated satisfactory relationships with measures of anxiety and depression [The PDS is a 49-item self-report measure of current PTSD symptoms related to a single identified traumatic event. It assesses all of the diagnostic criteria (A–F) for PTSD in DSM-IV and is composed of four parts. Part 1 is a trauma checklist including serious accident, natural disaster, non-sexual assault by someone you know, non-sexual assault by a stranger, sexual assault by someone you know, sexual assault by a stranger, combat, sexual contact when young with someone 5 years older, imprisonment, torture, life-threatening disease, and “other” traumatic event (not captured by the categories). Part 2 asks the respondents to identify their most upsetting traumatic event, when it happened, if anyone was injured, if they perceived life threat, and whether the event resulted in helplessness or terror. Part 3 measures the severity of the 17 symptoms listed under categories B (intrusive recollections), C (avoidance/numbing), and D  in DSM-IV. Part 4 measures interference from these 17 symptoms. A total severity score (ranging from 0 to 51) is calculated based on the 17 symptoms in part 3 . The original scale has been found to possess excellent internal consistency (pression . The relα = .90), anxiety (α = .84), and depression scales (α = .82). It also correlates significantly with alternative measures of anxiety and depression [The HADS is a 14- item self-report measure designed to identify symptoms of anxiety and depression (separately) among patients in a medical setting. The anxiety and depression subscales each contain seven items rated on a four-point scale (0 to 3) with higher scores indicating greater severity. Consistent with the original , the Swepression .α = .79 to .91) and clinical validity when compared with other measures of health functioning [The 36-Item Study Short Form Health Survey (SF-36) is a 36-item self-report measure of non-disease-specific health and functioning widely used in health research. It is composed of 8 subscales, but only physical functioning (10 items) and general health (5 items) were used in this study. Scores on the subscales are transformed to a 0–100 scale with higher scores indicating a greater health state. Consistent with the English language original , the Swectioning .= never; 6 = very often) [α = .70 to .90) [The Multidimensional Pain Inventory  is a 61-item measure of pain-related functioning. Items are broken down into three sections, each composed of its own subscales. Only two subscales of the first section were used in this study: pain interference (11 items) and life control (4 items). Items are rated on a 7-point scale (0 y often) . The ori to .90) , and the to .90) , 52.. The NRS is commonly used in pain clinics and research and been shown to be a valid and sensitive measure of pain intensity [The Numerical Rating Scale (NRS) is the most widely used measure of pain intensity in both research and clinical settings. It is composed of a single item wherein the patient rates the intensity of their pain over the past week on a scale ranging from 0 (no pain) to 10 (worst possible pain)ntensity , 54.α = .67 to .76) [The Tampa Scale of Kinesiophobia (TSK) is a 17-item self-report measure of fear of movement or (re)injury. Items are rated on a 4-point scale  with higher scores indicating greater fear of movement/(re)injury. The TSK, including the Swedish version used in this study, has been shown to have satisfactory psychometric properties ( to .76) , 55, 56  to .76) , 56, 57.r = .30 and a Cronbach’s alpha above .70 were considered acceptable [The internal consistency and reliability of the PDS were examined via inter-item correlations, item-total correlations, and Cronbach’s alpha. Item-total correlations above ceptable . Construceptable .χ2/df; acceptable fit <5) [χ2/df) was used instead of the traditional chi-square value together with the associated p value because it reduces the likelihood of falsely rejecting the model when one uses large sample sizes as was done here [Confirmatory factor analyses were undertaken using maximum likelihood estimation procedures with goodness of fit evaluated by the relative/normed chi-square statistic ( fit <5) , the roo fit <5) , and the fit <5) , 62. Theone here . Item loone here . The samone here , 65.p values were used to test for significance to reduce the likelihood of type I error [The prevalence of trauma, trauma type, and a current PTSD diagnosis were examined. Next, a multivariate analysis of variance (MANOVA) was conducted to test whether a linear combination of clinical characteristics  differed between three subgroups of chronic pain patients: group 1 = those fulfilling criteria for PTSD; group 2 = those exposed to trauma and not fulfilling PTSD criteria; and group 3 = those with no history of traumatic exposure. Patients were divided into these groups using all the DSM-IV criteria for PTSD (A to F) as measured by the self-report measure PDS. Univariate analyses of variance (ANOVAs) on each of the dependent variables or clinical characteristics were conducted as follow-up tests to the MANOVA. Post hoc analyses were performed to examine mean differences across the three groups on all clinical characteristics. Bonferroni-corrected  I error . All anap = .71), indicating that the data were missing at random. For the purposes of validating the PDS, only the 315 patients who reported a traumatic event on part 1 of the PDS were used in the analyses. For this subsample of trauma-exposed patients, the percentage of missing data was again very low (range = 0 to 4.8%), and Little’s MCAR test was non-significant , indicating that the data were missing at random. Consequently, it was deemed acceptable to use data from all patients and to impute missing values using the expectation-maximization (EM) method [n = 21) were identified by computing standardized scores using absolute z values larger than 3 as a cutoff. The affected values of the outliers were winsorized and included in all analyses [Of the 463 patients included in the study, a total of 24 (5%) had enough missing items on the PDS such that it was not possible to determine if they currently met the DSM-IV criteria for PTSD, and they were excluded from all further analyses. For the remaining 439 patients included in the descriptive analyses, percentage of missing data for clinical variables was very low (range = 0 to 4.8%) and Little’s MCAR test was non-significant  method . Visual ) method . Therefoanalyses .r = .20 to .73), and item-total correlations were consistently ˃.30 analyzing all symptom severity items together (range = .45 to .71). Cronbach alphas for the total score (based on symptom items only) was high (α = .92). The Cronbach alphas for the items comprising the three-factor model (corresponding to DSM-IV criteria) were as follows: factor 1 (re-experiencing), α = .89; factor 2 (avoidance/numbing), α = .85; and factor 3 , α = .82. Cronbach alphas for the emotional numbing four-factor model (similar to DSM-5 PTSD criteria) were as follows; factor 1 (re-experiencing), α = .89; factor 2 (avoidance), α = .72; factor 3 , α = .82; and factor 4 , α = .82. The mean total score on the PDS was 15.58 (SD = 11.72) for the entire sample and 25.36 (SD = 9.61) for patients who met criteria for a current diagnosis of PTSD, corresponding to the moderate to severe range of symptom severity. The mean total score for patients who reported a trauma but did not meet current PTSD criteria was 8.97 (SD = 7.71), corresponding to the mild range of symptom severity.The response rates were above 95.6% for all 17 symptom severity items. All items correlated with each other at an acceptable level . Table Correlations between PDS total score (symptom severity) and total scores on each of the three factor-derived subscales ranged from χ2/df) and unsatisfactory fit values (RMSEA)  reported experiencing at least one previous trauma(s). Of these trauma-exposed patients, a total of 127 fulfilled DSM-IV criteria (A–F) for PTSD based on their responses to the PDS  = 4.36; p < .001), with 9% of the variance in the canonically derived dependent variable accounted for by group membership. This significant MANOVA was followed by a series of ANOVAs for each of the dependent variables using Bonferroni-adjusted alphas (see Table p ≤ .05). Post hoc comparisons using Bonferroni-adjusted alpha indicated that group 1 had significantly higher levels of pain interference, kinesiophobia, anxiety, and depression and a significantly lower level of life control when compared with groups 2 and 3. Furthermore, group 1 had significantly higher pain intensity and lower physical functioning compared to group 2 as well as worse general health and more pain sites compared to group 3. Consistent with expectations, no significant differences on any of the variables were found between groups 2 and 3.A MANOVA was conducted to test the hypothesis that there would be significant mean differences between three groups of patients: group 1 = those fulfilling criteria for PTSD, group 2 = those exposed to trauma and not fulfilling PTSD criteria, and group 3 = those with no history of traumatic exposure, on a combination of their clinical characteristics measured prior to face-to-face assessment and treatment. A statistically significant effect was obtained . Overall, this Swedish language version of the PDS demonstrated high levels of internal consistency and reliability as well as acceptable construct validity. Likewise, and in accordance with previous studies of the factorial validity of the PDS in samples selected because of exposure to trauma and not chronic pain, the three-factor solution based on the PTSD symptom clusters in the DSM-IV did not provide an optimal fit to the data , 36, 39.The second aim of this study was to investigate the prevalence of traumatic experiences, trauma types, and posttraumatic stress disorder (PTSD) in a sample of patients seeking treatment for chronic pain. Consistent with our hypotheses and previous studies of people with chronic pain –12, 16, The final aim of the study was to examine how indices of pain-related functioning vary with a history of traumatic exposure and PTSD diagnostic status as assessed by the PDS. Understanding the association between PTSD and chronic pain has been identified as an important focus of research with implications for the treatment of both conditions . The resIn line with our hypothesis, patients with chronic pain and PTSD in this study had much poorer clinical presentations than those without PTSD. Specifically, patients with chronic pain fulfilling criteria for PTSD reported significantly higher levels of anxiety and depression and significantly lower levels of life control compared to the other groups. Furthermore, patients with PTSD reported lower levels of physical functioning compared to the trauma-exposed patients without PTSD and worse general health than the non-trauma exposed group. Overall, this study provides support for the view that PTSD symptoms interact with those of chronic pain. The direction of causality and which specific aspects of the pain experience that interact with PTSD remains somewhat unclear and requires further investigation including longitudinal designs. We did not expect there to be, nor did we find marked differences in clinical characteristics between patients with chronic pain who had been exposed to a trauma and did not meet criteria for PTSD and those with no history of traumatic exposure.It is important to note that scores on the measure of anxiety and depression were elevated in the PTSD group compared to both comparison groups. This is consistent with previous findings , 22 but Current psychological treatments for chronic pain produce small to medium effect sizes, and chronic pain researchers have begun to try to identify the particular components of psychological treatments (or mechanisms) which work for different patients and to try to understand why , 71. WhiFindings from the present study must be viewed within the context of certain limitations. It was not possible to investigate all relevant psychometrics in this study as the standard assessment protocol of the clinic from where this sample was drawn does not include structured clinical interviews or other self-report measures of PTSD. Hence, future studies are needed to further assess the construct validity of this Swedish translation of the PDS and complement the analyses with other reliability and validity indicators. The Swedish version of the Numerical Rating Scale for pain intensity has not been formally validated but is used throughout Sweden with chronic pain patients and shows high correlations with other pain-related measures . Also, tIn conclusion, this study supports the reliability and validity of this Swedish language version of the PDS. Consistent with previous research, a significant proportion of patients seeking treatment for chronic pain reported a history of traumatic exposure and nearly one third of these met current criteria for PTSD according to a standardized self-report measure. Patients with chronic pain and comorbid PTSD had much poorer clinical presentations than the trauma-exposed group without PTSD and the non-trauma-exposed group. The presence of PTSD was associated with multiple indictors of poorer functioning and greater treatment need and provides further evidence that routine screening of chronic pain patients for PTSD is warranted. Self-report measures like the PDS appear to be valid for use in chronic pain samples and offer a relative low-cost method for screening for PTSD.


Patients with concentrations < 400 ng/mL had significantly higher  cold pressor pain threshold (adjusted mean (95% CI) = 30.15  s) compared to those with concentrations of ≥ 400 ng/mL  seconds). There was also a 20% difference in pain tolerance, and 6% difference in cold pressor pain intensity score, neither of which were significant statistically (p > 0.05). Our results suggest an association of trough methadone concentration with the cold pressor pain threshold among opioid dependent patients on MMT. It would be useful to study the mechanisms underlying this association to help managing pain in such a population.Hyperalgesia is a common clinical phenomenon among opioid dependent patients on methadone maintenance therapy (MMT) and it may be associated with undertreated pain and/or therapeutic failure. This study aimed to investigate association between serum methadone concentration (SMC) and cold pressor pain responses. Cold pressor pain responses in 147 opioid dependent patients on MMT were assessed using cold pressor test (CPT) at 0 h and at 2, 4, 8, 12, and 24 h after the dose intake. Blood samples were collected at 24 h after the dose. Serum methadone concentrations were measured using the Methadone ELISA kit and classified into two categories: < 400 ng/mL and ≥ 400 ng/mL. Eighty-eight patients (59.9%) had trough concentrations of < 400 ng/mL and 40.1% had trough concentrations of ≥ 400 ng/mL. There were significant effects of SMC on the cold pressor pain threshold ( Research evaluating the healthcare costs associated with treatment of opioid dependence with medications found that patients who received medications including methadone had lower hospital utilization and total costs than patients who did not receive them . HoweverIn addition to medical provider barriers, patient factors may also contribute to poor pain management in opioid dependent patients. Physiological and psychological aspects of active opioid addiction can make pain management more difficult . Opioid Several studies on pain sensitivity among opioid dependent patients on MMT have been undertaken previously in several populations in California, USA -11,17,18Because of the hyperalgesia among opioid dependent patients on MMT may be associated with the under-treated pain and/or therapeutic failure , it is oThus, assessing the relationship of methadone concentrations in blood with the corresponding pain sensitivity can be useful to improve pain management among opioid dependent patients on MMT. The present study investigated pain sensitivity by using cold pressor test (CPT) with methadone steady-state trough concentrations measured in a group of 147 opioid dependent patients on MMT, against a hypothesis that there are significant relationships between methadone concentration and pain sensitivity. Patients Patients were consecutively recruited from those attending the Psychiatric Clinic, Hospital Universiti Sains Malaysia (HUSM), Psychiatric Clinic, Hospital Raja Perempuan Zainab II and eight other government MMT clinics in Kelantan. Opioid dependent patients on the MMT programme at a non-governmental organisation (NGO), SAHABAT between March and October 2013 were also asked to participate in this study. Inclusion criteria were: 1. Malay for at least up to three generations.2. Male aged more than 18 years.3. Free of acute medical, surgical and psychiatric illness.4. Free of acute or chronic medical, surgical and psychiatric illness that requires concurrent medical, surgical or psychiatric therapy.5. Free of regular use of alcohol.6. Free of intoxication.7. Able to understand study protocols and to follow simple study instructions.8. Willing to sign written informed consent.Exclusion criteria were patients with or taking: 1. diabetes mellitus. 2. human immunodeficiency virus (HIV) and were on highly active antiretroviral therapy (HAART). 3. major psychiatric illness such as schizophrenia.4. taking illicit benzodiazepines, cannabinoids and barbiturates. 5. peripheral vascular disease. 6. regular anticonvulsants, neuroleptics or analgesics. 7. chronic or ongoing acute pain. 8. a history of analgesics ingestion within three days before the cold pressor test (CPT).9. severe cognitive impairment which may interfere with pain assessments and/or communication.Urine drug screens were performed twice in one week prior to enrollment to ensure that exclusion criteria were not met. The selected subjects were interviewed by the researcher based on a standard performa Information recorded included socio-demographic variables and other relevant information. The study was approved by the Human Research Ethics Committee (HREC), Universiti Sains Malaysia (USM) in Kelantan, Malaysia (Reference number: USMKK/PPP/JEPeM (253.3 [14]) and the Medical Research & Ethics Committee (MREC) at the Ministry of Health (MOH), Malaysia (Reference number: NMRR-13-524-16614).Cold pressor test (CPT)et al. . The CPT method utilized in the current study was based on previous reports from Chen et al.  and Comp  ,15,24.The CPT apparatus consisted of a 48 quart cool box filled with a mixture of two-thirds crushed ice and one-third tap water. The resulting ice-water mix was stirred to maintain a constant temperature of 0 – 2 °C by adding ice with temperature constantly being monitored by a digital indoor-outdoor-thermometer .The pain threshold was defined as the mildest experience of pain that can be identified by a subject (i.e. time elapsed when the subject started to perceive pain after the immersion of hand). The pain tolerance was defined as the most severe pain that a subject was willing to tolerate . Both pain threshold and tolerance were quantified in sec. The CPT was truncated at 300 s, as after this time, numbness set in and pain diminished ,25,26. PAfter withdrawal of the immersed hand, each subject was given a piece of dry towel to dry their hand. Immediately after hand withdrawal, subjects were asked to subjectively score their maximal pain intensity using a valid and reliable instrument, the 0-100 visual analogue scale (VAS), where zero (0) represented no pain and a hundred (100) represented the worst pain imaginable ,28. Subjects were tested at 0 h [i.e. approximately 30 min before taking their morning dose of methadone (at about 8.00 AM)], and at 2, 4, 8, 12, and 24 h after the dose intake. We examined cold pressor responses six times over a 24 h period, in order to minimize the possible diurnal variation in cold pressor pain response . The tesBlood sampling and methadone assay procedureMethadone steady-state trough concentration  was asse-33.Blood samples had been collected at 24 h after the dose intake [i.e. immediately (approximately 30 min) before taking their morning dose of methadone] from the branula inserted. Blood samples were filled in a labelled plain glass tube. The blood samples were allowed to clot by leaving it undisturbed at room temperature for 15 to 30 min. The tubes were kept in ice pack and were sent to the Pharmacogenomic laboratory at the Institute for Research in Molecular Medicine (INFORMM), USM, Kota Bharu, Kelantan..Clotted blood samples taken from patients receiving MMT were centrifuged at 3,000 rpm for 10 minutes using the Thermo Scientific™ Sorvall™ ST 16 Centrifuge  to separate the cells. The resulting supernatant (liquid component or serum) was immediately transferred into a clean 2 mL screw cap polypropylene tube. The serum was apportioned into 1.0 mL aliquots and stored at – 20 °C until use. Multiple freeze-thaw cycles of the serum samples was avoided to minimize protein degradationThe serum methadone concentrations (SMCs) were measured using the three-step ELISA method, Methadone ELISA Kit that was developed and validated by other researchers in the Pharmacogenetics and Novel Therapeutics Cluster, Institute for Research in Molecular Medicine (INFORMM) as previously described , 34. TheThe Methadone ELISA Kit uses a competitive enzyme immunoassay method to determine the amount of methadone present in a serum sample and it is suitable for routine use in clinical settings . This kiStatistical analysisContinuous variables were summarized as mean (SD) and categorical variables as frequency. The serum methadone concentration was classified into two categories: < 400 ng/mL and ≥ 400 ng/mL. The effects of serum methadone concentration were analyzed by comparing the cold pressor pain responses in opioid dependent patients with methadone concentration at 24 h post-dose of below 400 ng/mL and 400 ng/mL and above by means of repeated measures analysis of covariance (RM-ANCOVA), adjusting for methadone dosage. The limit of significance was set at 0.05. The statistical analysis was carried out using SPSS/Win software . Patients Results were based on the data of 147 participants. The mean age was 36.89 years . Subjects had been undergoing MMT for a mean of 2.83 years . All MMT subjects were in the stable maintenance phase of treatment, the dosage of which had been individually optimized and had not changed for more than one month; this allowed determinations of the trough steady-state methadone concentrations. Out of the 169 potential subjects, 148 took methadone in a single dose  and six split their daily dose into two portions. One patient had incomplete blood samples at 24 h. The other 15 patients were excluded for miscellaneous reasons. The mean daily methadone dose was 72.70 mg/day . Ninety-three patients (63.3%) received a daily methadone dose of < 80 mg/day and 54 (36.7%) received daily methadone dose of ≥ 80 mg/day. Cold pressor pain responses in opioid dependent patientsSerum methadone concentration (SMC) dataThe mean (SD) methadone concentration at 24 h (in ng/mL) was 387.78 (309.42) and it ranged from zero to 1672 ng/mL. Eight patients had trough methadone concentrations below the lower limit of quantification of 50 ng/mL at 24 h (their methadone concentrations were recorded as zero). When we applied a lower limit of 95% confidence interval for mean of 337.35 ng/mL and an upper limit of 438.22 ng/mL of trough methadone concentration on our sample, we detected that 78 (53.1%) patients had concentration below the lower limit and 52 (35.4%) above the upper limit. Eighty-eight patients (59.9%) had concentrations of below 400 ng/mL and 40.1% had 400 ng/mL and above, 400 ng/mL being the proposed necessary concentration to provide stabilized maintenance -33. p > 0.05). There was a difference between groups for methadone dose (p = 0.003), so that patients with concentrations of below 400 ng/mL received significantly lower daily methadone dose than those with concentrations of 400 ng/mL and above.The comparisons between patients with concentrations of below 400 ng/mL and those with concentrations of equal to or more than 400 ng/mL in demographic characteristics are shown in p < 0.001). In addition, separate analysis of the methadone dosage revealed that significantly higher methadone concentrations were observed in patients treated with methadone at dosages of ≥ 80 mg/day [mean (SD) = 506.62 (337.48) ng/mL] compared with those treated at lower dosages of < 80 mg/day [mean (SD) = 318.78 (270.60) ng/mL] (Influence of serum methadone concentration (SMC) on cold pressor pain responsesp = 0.019), but not on cold pressor pain tolerance and cold pressor pain intensity score (p > 0.05)  . The cold pressor pain threshold in opioid dependent patients, according to serum methadone concentration groups (concentrations of < 400 ng/mL and ≥ 400 ng/mL), adjusted for daily methadone dose are shown in p = 0.025).Patients having methadone concentrations of < 400 ng/mL had significantly higher cold pressor pain threshold (adjusted mean (95% CI) = 30.15  s) compared to those with concentrations of ≥ 400 ng/mL  s). In addition, exclusion of data from eight patients who had concentrations below the lower limit of quantification of 50 ng/mL did not alter this association  distributions in our current study.In summary, this study reports a possible relationship between trough serum methadone concentration and cold pressor pain threshold. As such, it indicates that identifying the trough serum methadone concentration of opioid dependent patients on MMT may allow individualization of methadone substitution treatment. Results of serum methadone concentrations would be of particular importance during management of pain in this patient population, when it is critical to avoid misconception such as “drug-seeking” behaviors and more importantly, treatment failures such as patient relapsing to active substance abuse. In the future, doctors or other health care providers working in maintenance programs may apply the results of pain sensitivity test and methadone concentration to provide pain relief for opioid dependent patients who are in need of pain management in order to improve patient care and overall treatment outcomes.


Propofol injection pain (PIP) has been adequately studied during the past decades. However, patients’ opinion on this problem and the incidence of patients’ recall of this brief discomfort are still unknown. Thus, we conducted this study to know the patients’ perspectives on PIP and provide useful information about the incidence of recall of PIP under our routine general anesthesia.Five hundred preoperative questionnaires were distributed to patients who were scheduled for elective open thyroidectomy under general anesthesia from May 2016 to July 2016. They were asked to rank ten possible adverse effects associated with general anesthesia from their most undesirable to their least undesirable effect. Patients who completed the preoperative questionnaires were asked whether they could recall PIP and to grade the severity of PIP on the first postoperative day.A total of 448 preoperative questionnaires were returned and analyzed with an efficient rate of 89.6%. Incisional pain was ranked as most undesirable, followed (in order) by vomiting, gagging on the tracheal tube, nausea, sore throat, propofol injection pain, shivering, intravenous puncture pain, and anxiety. The majority (91.5%) of surveyed patients could not recall any discomfort or pain during anesthetics injection. Of those who could recall PIP, 89.5% grade it as mild pain, 7.9% moderate pain, and 2.6% severe pain.Most of patients undergoing elective open thyroidectomy in our hospital viewed PIP as a relatively minor problem. The incidence of recall of PIP was low and the majority of those who recalled regarded it as mild, temporary and acceptable pain. However, further investigations into propofol injection pain may be warranted as patients’ perspectives on propofol injection pain and its severity may differ between patient populations. With the development and improvement of surgical and anesthetic techniques, critical incidents such as cardiac arrest or death during the perioperative period have been obviously minimized. In turn, more attempts have been made to address minor but potentially distressing clinical anesthetic problems such as pain, postoperative nausea and vomiting to further improve the quality of anesthesia care .Propofol injection pain (PIP) is one of these problems and it was ranked seventh among the most important 33 low-morbidity clinical anesthesia problems by a panel of expert anesthesiologists . The issThus, we performed this study to (1) know the patients’ perspectives on PIP by ranking their preferences for avoiding specific low-morbidity but common clinical anesthesia problems and (2) provide useful information about the incidence of recall of this brief discomfort under our routine general anesthesia.A list of the most common but low-morbidity clinical events associated with general anesthesia was derived from previous relevant studies –8. AfterPatients older than 18 years with thyroid carcinoma who were scheduled for elective open thyroidectomy under general anesthesia were eligible for our study. They were surveyed before and after surgery. We excluded individuals who had communication problems, were unable to speak or read Chinese, or incapable of understanding the contents of questionnaire. Those who refused to participate were also excluded. We distributed 500 preoperative questionnaires from May 2016 to July 2016 and aimed to collect at least 400 completed questionnaires. All the completed questionnaires were collected anonymously.The final preoperative questionnaire consisted of two parts: standard demographic items including age, sex, and previous experience of surgery, and a rankings section. In the rankings section, we asked patients to rank the 10 specific items. We used priority ranking scales to determine their preferences. Detailed instructions were given to the included patients to help them understand this ranking technique well. For example, “please rank each of these problems (you might experience) in relation to each other from 1 to 10 (1 = the most undesirable to 10 = the most desirable). Assume that each hypothetical situation occurs with equal frequency and would have the same duration. Each ranking number should be used only once.” One trained investigator (W.W.) who did not participate in patients’ anesthesia was responsible for distributing the questionnaire, explaining and answering any question asked by patients during this process. Moreover, the investigator reminded patients that there was no standard or right answer and they were encouraged to express their own views. Preoperative questionnaires would be considered valid or correct only if the normal outcome was ranked 10 (highest). Thus, we excluded all preoperative questionnaires that were not fully completed or were incorrect in our final analysis.Our study did not intervene in the anesthetic management of surveyed patients. In our routine anesthesia practice, no premedication was given. A 20-gauge venous cannula was inserted into a forearm vein and standard monitors were placed upon patients’ arrival in the operating room. All patients were induced routinely with midazolam, propofol, opioids, cisatracurium/rocuronium and maintained with propofol or sevoflurane.Patients who completed the preoperative questionnaires were followed up the first day after surgery. They were asked by the investigator (L.X.W.) whether they could recall any discomfort or pain in the upper limb during anesthetics injection before falling asleep. For those who answered yes, we asked them to grade the severity of pain using a three-point scale  and compare it with intravenous puncture pain and incisional pain.N, %) or mean ± standard deviation (SD) when appropriate. Ranking data were analyzed by ANOVA using Student-Newman-Keulsa test. Independent sample T-test was used to determine the effect of the demographic data  on the ranking data. A P value less than 0.05 (two-tailed) was considered statistically significant. All data were analyzed with the SPSS software .Data were presented as frequency and percentage  of the included 448 patients were presented in Table Ranking data were shown in Table The incidence and intensity of recall of PIP on the first postoperative day was presented in Table Propofol has been widely used in clinical practice. However, pain after injection is one of the most common side effects of this intravenous anesthetic. It has been reported that propofol injection pain (PIP) occurred in 60% of untreated patients . This coHowever, is PIP really important to patients? Maybe such pain is considered important just by clinicians but not patients. Besides, as midazolam and propofol are commonly used in anesthesia induction, the amnesic effects of the two drugs may blunt recall of PIP after surgery –14. In oSo far, PIP has been adequately studied with plenty of labor forces and financial resources inputted. A great many effective non-pharmacological and pharmacological approaches have been recommended to prevent or alleviate PIP including venous occlusion by a tourniquet , alternaThere are some limitations to our study. Firstly, potential selection bias may exist in our study as the sample of patients surveyed was from a single tertiary specialized cancer hospital scheduled for elective open thyroidectomy under general anesthesia. We do not know whether similar results would be obtained in patients undergoing major surgeries or in patients with chronic pain conditions. Patients’ perspectives on PIP and its severity may differ between patient populations. Thus, the finding in our study should be generalized to other patient populations carefully and further investigations into PIP may be warranted. Secondly, our study population mainly included middle-aged and relatively well-educated patients. As cognitive biases may affect the results of survey based study , it is uIn our study, we found that most of patients undergoing elective open thyroidectomy viewed propofol injection pain as a relatively minor problem. The incidence of recall of propofol injection pain was low and the majority of those who recalled regarded it as temporary and acceptable pain, which was lighter than intravenous puncture pain. However, as patients’ perspectives on propofol injection pain and its severity may differ between patient populations, further investigations into propofol injection pain may be warranted.


Somatosensory profiling in affected and non-affected body regions can strengthen our insight regarding the underlying pain mechanisms, which can be valuable in treatment decision making and to improve outcomes, in patients with degenerative lumbar spine disorders pre-surgery. The aim was to describe somatosensory profiles in patients with degenerative lumbar spine disorders, to identify the proportion with altered somatosensory profile, and to analyze demographic characteristics, self-reported function, pain, and health pre- and 3 months post-surgery.In this prospective cohort study in a Spine Clinic, 105 patients scheduled for surgery for spinal stenosis, disc herniation, degenerative disc disease, or spondylolisthesis were consecutively recruited. Exclusion criteria were; indication for acute surgery or previous surgery at the same spinal level or severe grade of pathology. Quantitative sensory testing (QST) and self-reported function, pain, and health was measured pre- and 3 months post-surgery. The somatosensory profile included cold detection threshold, warmth detection threshold, cold pain threshold, heat pain threshold and pressure pain threshold in affected and non-affected body regions.P = 0.031), more often female (P = 0.005), had higher back and leg pain , lower mental health component summary score (SF-36 MCS) (P = 0.004) and larger pain distribution (P = 0.047), compared to others in the cohort. Post-surgery there was a tendency to worse pain, function and health in the group with altered somatosensory profile pre-surgery.On a group level, the patients’ somatosensory profiles were within the 95% confidence interval (CI) from normative reference data means. On an individual level, an altered somatosensory profile was defined as having two or more body regions (including a non-affected region) with QST values outside of normal ranges for reference data. The 23 patients (22%) with altered somatosensory profiles, with mostly loss of function, were older (On a group level, patients with degenerative lumbar spine disorders scheduled for surgery were within normal range for the QST measurements compared to reference values. On an individual level, an altered somatosensory profile outside of normal range in both affected and non-affected body regions occurred in 22% of patients, which may indicate disturbed somatosensory function. Those patients had mostly loss of sensory function and had worse self-reported outcome pre-surgery, compared to the rest of the cohort. Future prospective studies are needed to further examine whether these dimensions can be useful in predicting post-surgery outcome and guide need of additional treatments. Among patients scheduled for spinal surgery due to degenerative lumbar spine disorders , a majority have experienced pain for over three months. Persistent pain results from a complex interplay of many factors. Maladaptive neuroplastic changes in the central nervous system can be influenced by orthopedic structural pathology, as well as biochemical and psychosocial factors . Such chIn patients with low back pain (LBP), bedside neurological testing is recommended . HoweverQST can detect gain of sensory function in the form of lowered sensory thresholds  and loss of sensory function  , 4. ThroThis prospective cohort study with cross sectional and prospective analysis investigated pre-surgery sensory profiles and biopsychosocial factors. The study conforms to the STROBE statement checklist for cohort studies. The patients received oral and written information about the study 1week before the measurements. All participants provided signed consent at the time of QST measurements. The study was approved by the Regional Ethics Committee (Dnr 2013/410-31).A total of 105 patients were consecutively recruited at a Spine Clinic at a University Hospital, in Sweden, between September 2013 and December 2014. Inclusion criteria were; patients scheduled for surgery due to: disc herniation, spinal stenosis, spondylolisthesis (Grade 4) or degenerative disc disease, age between 25 and 80 years and fluent in Swedish. Exclusion criteria were; indication for acute surgery, previous surgery at the same spinal level or severe grade of pathology. Seventeen eligible patients chose not to participate due to the requirement of additional appointments at the hospital for QST.Sensory profile investigation included the following QST measurements: cold detection threshold (CDT), warmth detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), and pressure pain threshold (PPT). A standardized QST protocol , 14 was PPT was measured using a handheld electrical pressure algometer  with a 1-cm diameter probe. The patient was instructed to state when the pressure started to become painful, at which point the applied pressure was released , 14. PreQST measurements were performed 1 to 2 weeks prior to surgery by a single investigator, a physiotherapist working at the Spine clinic. During QST measurements, the patients were comfortably seated or lying down in a quiet room with an air temperature of 22 °C. At the start of testing, patients were asked to use a visual analogue scale (VAS) to rate the average pain intensity in their back and legs during the last 2 weeks, as well as their current pain intensity at rest . The patTo collect demographics and data regarding function, pain, and health pre-surgery the patients completed the questionnaire from the Swedish National Spine Register for spinal surgery patients (SweSpine)  and compFunction was measured using Oswestry Disability Index (ODI) , which iHealth-related quality of life was measured using the European Quality of Life instrument (EQ-5D) , 26, whiHealth was also measured with the Short Form Health Survey (SF-36) , which iSymptoms of depression and anxiety was measured using the Hospital Anxiety and Depression Scale (HADS) , which iThe Self-Efficacy Scale (SES) is a 20-item scale for assessing a patient’s confidence regarding activities of daily living . The scoFear avoidance was measured using FABQ , which iP = 0.05.Statistical analysis was performed using IBM SPSS statistics version 23. The level of significance was set to Sample size calculation: Using CPT, HPT and PPT as outcomes at least 23 patients in each group were required based on calculations from a previous study that compared healthy subjects and subjects with chronic WAD . For comt-test or Mann–Whitney U test for continuous variables, and the Chi-Square test or Fisher Exact probability test for categorical variables were used. In the t-test, if Levine’s test was significant, the P value for “equal variance not assumed” was reported.Patient demographics were analyzed using descriptive statistics, and are presented as mean and SD for continuous variables, and as frequencies and percentages for categorical variables. For between-group comparisons of demographic data, function, pain, and health, the unpaired Student’s Z-transformation, meaning that each QST value was matched for age and sex in the reference values [Z-transformation:The data in the sensory profiles data were compared with reference data, obtained of healthy subjects from studies of the German Research Network on Neuropathic Pain (DFNS) , 38. QSTZ-score of < −2 or >2 is outside of the 95% confidence interval (CI) of a normal standard distribution for healthy subjects [Z-score values of <0 indicate a loss of sensory function, while Z-score values of >0 indicate r a gain of sensory function [A subjects . Moreovefunction . For theZ-score of < −2 or >2 compared to reference data for CDT, WDT, CPT, HPT, or PPT.An altered somatosensory profile was defined as having two or more body regions including a normally non-affected body region, i.e., the hand and/or upper back—with a n = 61; 58.1%), disc herniation , degenerative disc disease , and spondylolysis/spondylolisthesis . Patients with spinal stenosis were significantly older (67.6 ± 7.6 years) than patients with disc herniation . A pain duration of > 2 years was reported by 55 patients (52.5%), and was significantly more common among patients with spinal stenosis compared to patients with disc herniation (P = 0.003).Table Z-score values between −2 and 2, meaning that the group values were within the 95% CI of the reference data , except for Z-scores of < −2 in CPT.Of the 23 patients with altered somatosensory profiles, 19 (83%) had P = 0.047).Compared to patients without an altered somatosensory profile, those with an altered somatosensory profile reported significantly higher pre-surgery back and leg pain VAS and lower score on SF-36 MCS Table . The posIn line with the study’s aim to investigate the proportion of individuals showing an altered somatosensory profile, 22% of patients were detected. These patients had alterations outside of normal range in two or more body regions, including a non-affected region. This can be considered a sign of generalized alteration of somatosensory function. Most of these patients had loss of sensory function. The group with altered somatosensory profile showed worse back and leg pain VAS and SF-36 MCS before surgery, and also had larger distribution of pain as reported in pain drawings pre-surgery. The 3 months post-surgery results with patient reported outcome measures could not confirm the pre-surgery differences between the group with- respectively without altered somatosensory function, but it showed a tendency with worse function, pain and health in the group with altered somatosensory profile before surgery. The study does not have the power to detect small differences since the group with altered somatosensory profile turned out to be small. Considering that 20–35% of the patients with spinal stenosis and disc herniation are doubtful or dissatisfied with the results at 1-year follow up post-surgery , it stilWhen considering the other study aim, to describe somatosensory profiles of patients on a group level, Z-scores for QST data compared to reference data showed that our cohort was within the 95% CI of the reference values , 38. In The choice of QST measurements is of importance and in subjects with persistent pain, thermal pain thresholds are of greater importance than detection thresholds . People Z-score. Therefore, we suggest that the different profile in this particular group is related to other factors, which can be potential mediators of outcomes after treatment. Associations between sensory profiles and psychological variables have also been reported in studies of non-specific LBP [Patients with altered somatosensory profile had mostly loss of sensory function in current study. Similar result with loss of sensory function pre-surgery has previous been presented in patients with disc herniation , that stific LBP , WAD [14ific LBP . To our Generalizability is one important issue. The questionnaires used are internationally recommended self-reported questionnaires of function, pain, and health providing a thorough biopsychosocial description of the patient cohort. In the study, all patients are screened by an orthopedic surgeon and assessed as suitable candidates for surgery, in a shared decision with the patient. The population is representative of the population scheduled for surgery in Sweden when compared to the population included in the national registry SweSpine with regard to the proportions of different diagnoses, ages, genders, functions, and pain . AdditioIt has been reported that QST may have predictive value for identifying allodynia and hyperalgesia , but comOne limitation in the study was, in the protocol used in this study tests for cold stopped at +10°, while DFNS used 0°, indicating a risk for underestimation rather than overestimation of the results. When CPT in reference data had the broad normal range 32–0 °C in most age groups , 38, thaOn a group level, patients with degenerative lumbar spine disorders scheduled for surgery were within the normal range for the QST measurements compared to age and gender adjusted reference values. This might be interpreted as a well-selected patient group for surgery according to QST. However, on an individual level, 22% of the patients showed altered somatosensory profiles, when defined as alterations in two or more body regions, including a non-affected region, which may indicate disturbed somatosensory function. These patients had mostly loss of sensory function and reported worse pain and mental health components as well as larger pain distribution pre-surgery compared to the rest of the cohort. Differences 3 months post-surgery could not be confirmed partly due to limited study power. It remains to be determined whether baseline QST measurements have predictive value, and whether change over time is important for the outcome following interventions.


Chronic back pain is often a result of coexisting pathologies; secondary causes of pain can become more apparent sources of pain once the primary pathology has been addressed. The objective of our study was to determine if there is an increase in diagnosis of Sacroiliac joint pain following a Lumbar Rhizotomy. A list of patients who underwent Lumbar Radiofrequency during a 6-month period in our clinic was generated. Records from subsequent clinic visits were reviewed to determine if a new diagnosis of SI joint pathology was made. In patients who underwent a recent Lumbar Rhizotomy procedure to treat facetogenic pain, the prevalence of Sacroiliac joint pain increased to 70%. We infer that there is a significant increase in the diagnosis of Sacroiliac joint syndrome following a Lumbar Rhizotomy, potentially due to unmasking of a preexisting condition. In patients presenting with persistent back pain after Lumbar Rhizotomy, the clinician must have a high degree of suspicion for latent Sacroiliac joint pain prior to attributing the pain to block failure. It would be prudent to use >80% relief of pain after a diagnostic medial branch block as a diagnostic criterion for facetogenic pain rather than the currently accepted >50% in order to minimize unmasking of preexisting subclinical pain from the SI joint. Low back pain is the most common pain in the modern society with estimates of lifetime prevalence as high as 84–90%  and the Based on the number of Lumbar Radiofrequency rhizotomies performed at our institution within the study period, we estimated that we would reach a study population of 100 patients. In order to be able to account for our exclusion criteria, we calculated that a sample size of 50 patients would provide us a margin of error of 13.8% at a 95% confidence interval in determining the association of Sacroiliac joint dysfunction in clinic visits following a radiofrequency rhizotomy [A total of 96 patients underwent the radiofrequency rhizotomy procedure during the study period. Of these, 46 patients were excluded, as they did not have the required minimum of 2 follow-up visits after the procedure. Of the 50 patients included in the study, 66 percent of the subjects were female and 34 percent were male. Age of the patients ranged from 34 to 84 with an average age of 57.8 years. DePalma et al.'s study population included patients referred to a Chronic Pain Clinic from various specialists and included patients with back pain for at least 12 months. The mean age of the included patients was 52.8 years and 65% of subjects were female [Among the 50 patients, 35 patients developed Sacroiliac joint pain or had worsening of their preexisting SI joint pain . Of thesχ2(1) = 27.435, p < 0.001. Phi (φ) and Cramer's V were also calculated to assess the strength of association between the variables of Sacroiliac pain and a recent history of radiofrequency rhizotomy (φ = 0.524, p < 0.001 (The incidence of SI joint dysfunction was as high as 70% in our postrhizotomy sample but only 18.2% in DePalma et al.'s study of similar low back pain patients who did not undergo radiofrequency rhizotomy . A chi-shizotomy . All the < 0.001 .Several factors have been associated with the development of Sacroiliac joint pain including injury from accidents and falls, gait abnormalities, pregnancy, leg length discrepancies, scoliosis, ankylosing spondylitis, psoriatic arthritis, and previous lumbar fusion surgery , 10–12. Our study suffered from several limitations. Firstly, our study population was limited by our relatively recent transition to the EPIC system in our clinic. Due to the time frame of our data collection of 6 months, several of the patients could not complete the required minimum of 2 postprocedural follow-up visits, decreasing our study population to 50. Although the primary reason for lack of follow-up was the inability to make appointments within the time frame of our data collection, the lack of pain after the procedure cannot be ruled out as the reason for patients not following up. Secondly, our control group was chosen from a different study. DePalma et al. utilized multiple interventions including discography, diagnostic Sacroiliac joint injections, and interspinal ligament injections in order to delineate and determine the cause of back pain in a sample of patients presenting to a Chronic Pain Clinic, while we relied on physical examination findings alone to diagnose Sacroiliac pain in patients presenting for follow-up visits after a Lumbar Rhizotomy performed for facetogenic pain. Although we made efforts to minimize the differences between the demographics and characteristics of both groups, it would have been ideal to choose the groups from the same clinic. We did start this endeavor and such study is underway in our clinic currently. Larger studies are certainly needed to shed further light on this interesting phenomenon.In summary, our study brings up three important points. Firstly, in patients presenting with persistent low back pain after having a lumbar medial branch radiofrequency ablation, the clinician must have a high degree of suspicion for Sacroiliac joint pain prior to attributing the pain to block failure. Secondly, it emphasizes the importance of a comprehensive physical examination in any patient presenting with lower back pain. Provocative Sacroiliac joint maneuvers such as FABER-Patrick's test and Gaenslen's test must always be performed during the pre- and postprocedural clinic visits in patients with lumbar zygapophyseal joint pain. These physical examination maneuvers should ideally be followed by confirmatory diagnostic joint blocks prior to therapeutic measures. Thirdly, it highlights the importance of clearly defining the index pain and utilizing a cut-off of 80–100% reduction in pain after a diagnostic facet block as utilizing a conventional >50% pain relief may result in residual pain from a preexisting chronic condition that may become unmasked after the Lumbar Rhizotomy procedure.