spinal canal stenosis is a syndrome of various etiology , whose morphological manifestation is narrowing of the spinal canal , intervertebral foramina , and lateral recesses . it is the most common cause for surgical treatment in patients over 65 years of age . in the surgical treatment for lumbar stenosis , various methods have been applied , which have been described in the literature as plif ( posterior lumbar interbody fusion ) , with or without additional transpedicular stabilization aimed at achieving the right intervertebral space and stabilizing the motor segment under treatment [ 46 ] . however some authors have investigated the role of ceramic - based grafts that enable large - scale production , biocompatibility , an appropriate safety profile , and the ability to closely mimic physiological bone . the aim of the study was to compare long - term results of efficacy of plif versus fenestration of patients with lumbar stenosis treated with : decompression of neural structures and interbody fusion with ceramic corundum implants , and fenestration without restoring intervertebral space and gaining stability . after obtaining approval by the institutional ethics committee , 100 patients with single - level lumbar spinal stenosis due to disc degeneration were surgically treated during the years 19982002 . all the patients were prospectively qualified for surgery by an experienced spine surgeon who is the chief of the spine surgery department . all patients had neurological examination followed by radiological imaging ( x - ray , mri , and/or ct ) to confirm the diagnosis . the criteria for qualification for the groups researched were the following : severe back pain radiating to 1 or both of the legs , neurogenic claudication below 200 m , no improvement despite 3-months of appropriate physiotherapy , and stenosis requiring resection of more than 50% of facet joints . the criteria for denying the treatment were : lack of patient consent , spondylolisthesis , and other pathological abnormalities ( e.g. , metastasis , infection , or fracture ) . the sample size had been assumed to be n=50 , based on sample sizes applied in similar studies published before . the statistical analyses were correct , so we found corrections and enlarging the group were not necessary . group a consisted of 50 patients treated with decompression of the entrapped neural elements , enlargement of the intervertebral foramina through disc space elevation by us of ceramic corundum implants , and providing immediate motion segment stability supplemented without posterior instrumentation . group b consisted of 50 patients treated with decompression of neural structures by fenestration with facetectomy of inferior articular processes . the corundum implants were designed at the department of orthopedic surgery of the center of postgraduate medical education in otwock in cooperation with the glass and ceramic institute . the porosity of implants is similar to that of the mineral structure of the cancellous bone , and their resilience modules were also similar . the implant , after it fuses with bone , forms a resistant composite , well visible in x - ray images , as it does not undergo resorption . the bioceramic corundum implants are made of close - grained aluminium oxide al2o3 and fired at 1730c . figure 2a and 2b show ap and lateral view of 3d - ct image of the lumbar spine 10 years after surgery . porous corundum implants are visible in the l4-l5 interbody space . the results were evaluated through 2-factor repeated measures analysis of variance . the between - subject factor was the type of surgical treatment , and the within - subject factor was the change of results following the treatment . the between - subject factor was the type of surgical treatment , and the within - subject factor was the change of results following the treatment . differences between duration of operation , intraoperative blood loss , time to ambulation , and hospitalization were significantly different for p<0.05 in favor for the decompression group . all the patients were monitored by the operating surgeon at 6 weeks , 6 months , and 1 year after surgery , and then annually . the subjective scale of disability as expressed by the patients , based on the oswestry disability index , , the rolland- morris disability questionnaire , and the visual analogue scale ( vas 010 ) , were used as the treatment effectiveness criteria . functional scales were collected from the patients before surgery , 1-year after surgery , and ten years later . follow - up rate at the evaluation point at 1 year was 99 patients , and 93 at 10 years . it was impossible to get information from 3 patients belonging to group a ( 2 patients had died and 1 had changed address ) and from 4 patients belonging to group b ( all 4 had changed addresses ) ( figure 3 ) . the oswestry disability index prior to the treatment revealed serious disability ( 41.01% [ 10.10 ] ) for group a and full disability ( 63.80% [ 12.63 ] ) for group b ; the difference was statistically significant , with p<0.01 . the rolland - morris disability questionnaire revealed mean disability of 16.07% ( 5.88 ) in group a and 14.15% ( 3.24 ) in group b , but the difference was not statistically significant . the visual analogue scale ( vas ) revealed a mean pain level of 8.57 ( 1.21 ) in group a and 8.17 ( 0.9 ) in group b , but the difference was not statistically significant . the oswestry disability index revealed minimal disability at 1 year after surgery in group a , and moderate disability in group b. the difference between the groups was statistically significant , with p<0.01 . long - term results showed a slight insignificant increase of disability , but the difference between the groups was still statistically significant , with p<0.01 . the rolland - morris disability questionnaire at 1 year after the operation revealed mean disability of 8.57% ( 5.88 ) and 7.57% ( 5.83 ) after 10 years in group a , and 7.17% ( 4.42 ) after 1 year and 8.17% ( 4.44 ) after 10 years in group b. this difference between the groups was not statistically significant . the visual analogue scale ( vas ) revealed a mean pain level of 3.98 ( 2.14 ) after 1 year and 4.96 ( 2.13 ) after 10 years in group a , and mean pain level of 4.15 ( 1.59 ) after 1 year and 4.35 ( 1.69 ) after 10 years in group b. this difference between the groups was not statistically significant ( table 3 ) . the slight insignificant increase of patient disability in odi and rm scales as well as in vas scale were probably connected with aging . the analysis of variance of the oswestry disability index revealed a significant impact of the within - subject factor ( f1,91=899.97 ; p<0.001 ) . the improvement 10 years following the surgery evaluated by the oswestry disability index between the groups was statistically important . also , the interaction of factors was significant ( f1,91=50.126 ; p<0.001 ) ; therefore , the increase in patient health was greater . the surgical treatment resulted in achieving minimal and moderate disability according to the oswestry disability index in group a ; therefore , the clinical result was good in 44 patients ( 95.7% ) . the result was unsatisfactory ( disability was moderate ) in 2 patients ( 4.3% ) . the oswestry disability index revealed that the decompression performed in patients of group b resulted in a good clinical result in 45 patients ( 95.7% ) . like in group a , there were also 2 patients whose results were unsatisfactory . in the case of the rolland - morris disability questionnaire , the within - subject factor played an important role ( f1,91=132.46 ; p<0.001 ) , which shows that this questionnaire also revealed a decrease in patient disability . however , interaction of factors proved irrelevant here , and effectiveness of both methods with this questionnaire should be evaluated as being similar . the visual analogue scale ( vas ) confirms the abovementioned effects . a significant impact of the within - subject factor ( f1,91=476.97 ; p<0.001 ) was demonstrated , but there is no interaction between this factor and the method of treatment . the following complications were observed in group a : 1 patient had malposition of the corundum , but did not require reoperation . one patient in group a needed additional postero - lateral fusion with autologous graft due to instability . in group b , during 10 years of observation , 3 patients had surgery on this same segment due to recurrence of symptoms . the hypothesis that fusion of a single segment of the spine causes increased motion that leads to disc prolapse was not observed in the examined group . we observed adjacent segment lateral stenosis due to degenerative changes in intervertebral joints and ligamentum flavum thickening in :  4 patients ( 8.5% ) from group a ; they were re - operated at between 6 and 8 years after primary surgery , with a mean of 7.16 ( 0.63 ) years , and  6 patients ( 13.04% ) from group b , who were re - operated on between 3 and 7 years after primary surgery , with a mean of 5.13 ( 1.27 ) years . in both groups no patients were operated on due to disc extrusion during the follow - up period . the oswestry disability index prior to the treatment revealed serious disability ( 41.01% [ 10.10 ] ) for group a and full disability ( 63.80% [ 12.63 ] ) for group b ; the difference was statistically significant , with p<0.01 . the rolland - morris disability questionnaire revealed mean disability of 16.07% ( 5.88 ) in group a and 14.15% ( 3.24 ) in group b , but the difference was not statistically significant . the visual analogue scale ( vas ) revealed a mean pain level of 8.57 ( 1.21 ) in group a and 8.17 ( 0.9 ) in group b , but the difference was not statistically significant . the oswestry disability index revealed minimal disability at 1 year after surgery in group a , and moderate disability in group b. the difference between the groups was statistically significant , with p<0.01 . long - term results showed a slight insignificant increase of disability , but the difference between the groups was still statistically significant , with p<0.01 . the rolland - morris disability questionnaire at 1 year after the operation revealed mean disability of 8.57% ( 5.88 ) and 7.57% ( 5.83 ) after 10 years in group a , and 7.17% ( 4.42 ) after 1 year and 8.17% ( 4.44 ) after 10 years in group b. this difference between the groups was not statistically significant . the visual analogue scale ( vas ) revealed a mean pain level of 3.98 ( 2.14 ) after 1 year and 4.96 ( 2.13 ) after 10 years in group a , and mean pain level of 4.15 ( 1.59 ) after 1 year and 4.35 ( 1.69 ) after 10 years in group b. this difference between the groups was not statistically significant ( table 3 ) . the slight insignificant increase of patient disability in odi and rm scales as well as in vas scale were probably connected with aging . the analysis of variance of the oswestry disability index revealed a significant impact of the within - subject factor ( f1,91=899.97 ; p<0.001 ) . the improvement 10 years following the surgery evaluated by the oswestry disability index between the groups was statistically important . also , the interaction of factors was significant ( f1,91=50.126 ; p<0.001 ) ; therefore , the increase in patient health was greater . the surgical treatment resulted in achieving minimal and moderate disability according to the oswestry disability index in group a ; therefore , the clinical result was good in 44 patients ( 95.7% ) . the result was unsatisfactory ( disability was moderate ) in 2 patients ( 4.3% ) . the oswestry disability index revealed that the decompression performed in patients of group b resulted in a good clinical result in 45 patients ( 95.7% ) . like in group a , there were also 2 patients whose results were unsatisfactory . in the case of the rolland - morris disability questionnaire , the within - subject factor played an important role ( f1,91=132.46 ; p<0.001 ) , which shows that this questionnaire also revealed a decrease in patient disability . however , interaction of factors proved irrelevant here , and effectiveness of both methods with this questionnaire should be evaluated as being similar . . a significant impact of the within - subject factor ( f1,91=476.97 ; p<0.001 ) was demonstrated , but there is no interaction between this factor and the method of treatment . the following complications were observed in group a : 1 patient had malposition of the corundum , but did not require reoperation . one patient in group a needed additional postero - lateral fusion with autologous graft due to instability . in group b , during 10 years of observation , 3 patients had surgery on this same segment due to recurrence of symptoms . the hypothesis that fusion of a single segment of the spine causes increased motion that leads to disc prolapse was not observed in the examined group . we observed adjacent segment lateral stenosis due to degenerative changes in intervertebral joints and ligamentum flavum thickening in : 4 patients ( 8.5% ) from group a ; they were re - operated at between 6 and 8 years after primary surgery , with a mean of 7.16 ( 0.63 ) years , and  6 patients ( 13.04% ) from group b , who were re - operated on between 3 and 7 years after primary surgery , with a mean of 5.13 ( 1.27 ) years . in both groups no patients were operated on due to disc extrusion during the follow - up period . ceramic implants used in the plif surgical treatment have not been widely discussed in the english literature in the last 10 years . reported the early treatment outcomes of plif with corundum implants evaluated according to the oswestry disability index . in almost 80% of patients , the clinical result achieved was good or satisfactory . these implants were supposed to be an alternative to metal implants , which are much more expensive . also , the surgical treatment with the use of interbody metal implants is much more extensive , with the risk being much higher than in operations without the use of any implants [ 1214 ] . corundum implants discussed in this paper were used in 50 patients with clinical symptoms of single - level stenosis . it was assumed that the interbody fusion would ensure stability and eliminate the cause of the pain , while the reconstruction of the intervertebral space height would prevent or delay the development of secondary stenosis on the reconstructed level . the long - term results in group a showed that patients treated by interbody fusion with the use of ceramic corundum implants have not exceeded the long - term results of treatment without the interbody fusion . treatment by decompression was , however , less invasive . in this kind of treatment , the justification for this treatment was the conviction that degenerative changes in posterior facet joints and intervertebral discs in their natural process of development lead to a secondary stabilization of the motor segment . additionally , the precise determination of the level of condition through clinical examination , as well as the removal of its cause ( the compression on neural structures ) in the course of the surgical treatment , is a well - documented course of action . during the decompression procedure , if the intervertebral joint is retained with a part of inferior articular process , the vertebral arches and processes , together with the anterior wall of the spinal canal and posterior longitudinal ligament , the neurological structure can be decompressed without causing instability on the operated level . they evaluated short - term results of treatment of lumbar stenosis by 2 different methods of decompression : fenestration and laminectomy . they advised performing a surgery with minimal intervention because this makes the surgery less expensive . watanabe et al .   reported that they used the plif procedure to implant 31 patients ( 33 segments ) , in combination with segmental pedicle screws , interbody cages , and autogenous local bone graft , achieving excellent clinical outcomes , and in their opinion it was a rational and useful surgical option for treatment of lumbar foraminal stenosis . weiner et al . treated patients with severe stenotic changes by tlif ( transforaminal lumbar interbody fusion ) and found that this technically demanding procedure could be performed with relatively few complications and offered excellent rates of arthrodesis . a similar conclusion was reached in a register study of 9051 patients by sigmundsson et al . they concluded that patients with predominant back pain undergoing decompression and fusion were more satisfied with their treatment at 1-year follow - up and had better outcome in terms of health - related quality of life than patients who underwent decompression only . promising results combining advantages of both methods  minimal approach and fusion  were reported by perez - crues et al . , was reported the short- and long - term outcomes from a large cohort ( n=304 ) of patients undergoing minimally invasive transforaminal lumbar interbody fusion ( mitlif ) . similar to our findings , the above - mentioned authors stated that the vas scores decreased significantly ( from 7.0 preoperatively to 3.5 ) and the oswestry disability index scores declined from 43.1 preoperatively to 28.2 at mean 47-month follow - up . moreover , the long - term benefits observed in this study included a reduced rate of adjacent segment disease requiring reoperation , while providing high rates of fusion and a low rate of complications . the ideal and long - lasting surgical treatment of lumbar spinal stenosis with associated mild spinal deformity is still debated in the literature and reported results vary . found that spinal canal decompression improves the functioning of the patients , and reduces back pain and lower limb pain . conducted a retrospective cohort analysis of 90 consecutive patients ( mean age 70 years ) , with 5-year mean follow - up , treated for stenosis with associated deformity , using 3 different methods : interspinous process spacer ( isp ) device placement , laminectomy alone , or laminectomy and short - segment fusion . the authors stated that there was a significantly higher rate of same - level recurrence in the isp group ( 33.3% ) than the laminectomy ( 8.3% ) and laminectomy combined with fusion ( 0% ) groups . deyo et al . , in a retrospective cohort analysis including 99 084 patients who underwent surgery for spinal stenosis , used different methods : an the interspinous process spacer ( isp ) device placement alone , laminectomy and spacer , decompression alone , or decompression with fusion , and reported the revision rates at 2 years to be 16.7% for the isp , 8.5% for decompression alone , and 9.8% for lumbar fusion . . results of reoperation in decompression alone and in lumbar fusion were comparable at 2 years after surgery . we have obtained similar results , with 8.5% reoperations in the fusion group , and 13.04% in the decompression group , but our observation period was much longer . another way to evaluate the benefits of performed surgery is measuring the level of patient pain , functioning , and disability . in our study , at 10-year follow - up , the results were still beneficial , and observed disability was minimal to moderate . japanese authors in a prospective study evaluated 70 patients in whom laminectomy with or without arthrodesis was performed by vas scale . they found that the results of the surgery improved steadily for 6 months after the operation , and then remained stable for the next 5 years . in elderly patients , especially women , our results showed a decrease in pain level after surgery , from vas 8.57 in the plif group and 8.17 in the decompression group , to 4 and 4.17 after 1 year , and slight increase to 4.96 and 4.35 , respectively , after 10 years . an important measure of the value of surgery was also the percentage of patients who return to work ( rtw ) . nguyen et al . analyzed long - term ( 10-year ) results in 725 patients treated with arthrodesis compared to 725 controls who were randomly selected . they discovered that 26% of fusion cases had rtw , while 67% of nonsurgical controls had rtw . surgery was connected with a large percentage ( 27% ) of re - operation . in 36% of patients , there were complications and a large increase in using opioid drugs when compared to the control group not treated surgically . in this study , we did not analyze the rate of return to work , but most probably this problem is significant . a total of 75% of the patients operated on for lumbar spinal stenosis do not return to their preoperative work . difficulties in returning to work and decreased quality of life are associated with female sex , lower education , hard physical work , and low income . it is a process which enables the fastest possible patient recovery and helps to achieve optimal activity in a way that is safest for the patient [ 2224 ] . long - term results evaluated according to the odi , the rolland - morris disability questionnaire , and the vas showed that both methods gave significant reduction in patient disability , which was maintained during the next 10 years . the less invasive fenestration procedure was only a little less favorable than surgical treatment of stenosis by both plif with corundum implants and decompression .