a well - functioning permanent vascular access is crucial for the survival of patients on maintenance hemodialysis as it provides sufficient blood flow for dialysis . because adequate blood flow is provided by the arteriovenous fistula ( avf ) with the fewest complications , avf the national kidney foundation 's kidney disease outcomes quality initiative ( nkf - kdoqi ) is keeping in attempts to improve the utilization of the avf in patients who receive maintenance hemodialysis . it was reported by the united states renal data system ( usrds ) that hemodialysis access failure remains to be the most frequent cause of hospitalization . all kinds of complications , including stenosis , thrombosis , abnormal establishment of collateral branches circulation , and so on , may lead to a dysfunction of the avf or inadequate dialysis , which eventually has an impact on the quality of life of the patients or even makes the vascular access unusable . the buttonhole cannulation , also called the constant site cannulation , has been successfully used in home hemodialysis and dialysis centers to reduce bruising , prolonged bleeding , and aneurysm formation . we report the case of a 47-year - old male ( chinese ) , who was diagnosed with end - stage renal disease ( esrd ) . a mature avf on the left wrist was operated 5 years ago , and the wrist recovered its function 2 months after the operation . at the end of the fourth year of hemodialysis , the ultrasound dilution technique was applied for surveillance of the function of the fistula , showing a recirculation of zero ( transonic hd02 monitor ; ithaca , ny , usa ) and an access flow rate ( qa ) of 1,360 ml / min . the spkt / v was 1.28 , which indicated that the avf was functionally effective . two months later , the buttonhole cannulation technique was applied due to fistula punctuation difficulty with previous aneurysmal dilatation . after 10 times of buttonhole cannulation , the patient experienced gradual edema on the left forearm as well as insufficient blood flow of the fistula [ fig . 1 ] . the recirculation of the avf was 87% with a blood flow ( qb ) of 220 ml / min and a spkt / v of 0.75 , which indicated a dysfunction of the avf . this was further confirmed by a vascular ultrasound of the avf , revealing abnormal fistula between the mature cephalic vein and the radial vein [ fig . 2 ] where blood shunt existed , together with thrombus in the proximal cephalic vein and aneurysmal dilatation in the distal segment [ fig . 3 ] that developed 3 years ago . the site for punctuation was changed , and a reduction of recirculation to 25% with qb 240 ml / min could be confirmed 2 weeks later . the utilization of the new avf began 4 months after the operation and has been working well until now . a well - functioning avf is the key to long - term maintenance hemodialysis in patients with esrd . one of the major causes of dialysis inadequacy is the dysfunction of vascular access secondary to vascular access complications . despite the fact that the avf has the least complications and is the preferred method of dialysis access , every permanent access may lead to complications associated with low blood flow and recirculation , such as failure of maturation , venous stenosis , thrombosis , and so on . in our case , thrombus was found in the proximal cephalic vein with aneurysmal dilatation in the distal segment . emergency hospitalization for 15 days was necessary because of cardiopalmus , dizziness , and hyperkalemia . in fact , the most common causes of hospitalization associated with access complications in dialysis patients include insufficient blood flow , vascular access - related infections , limb ischemia , and aneurysms . in the case reported herein , the complication of abnormal fistula on the avf occurred during the shift from traditional cannulation ( rope - ladder cannulation ) to buttonhole cannulation . rope - ladder cannulation , which is characterized by the variation of the needling site , is considered the most frequently used technique in comparison with other kinds of cannulation . the purpose of buttonhole cannulation is to form a scar tissue tunnel track between skin and vascular access to allow a dull - tipped needle to access the avf following the same path during every dialysis session by means of repeated needle puncture at exactly the same site and angle . this technique may reduce the incidence of vascular access complications with the clinical manifestation of bruising , prolonged bleeding , and aneurysm formation . several studies have shown that buttonhole cannulation is a valuable technique with less hematoma , aneurysm formation , and cannulation pain than the rope - ladder cannulation technique and that is easy to self - cannulate , which is particularly relevant for home hemodialysis [ 5 , 6 , 7 ] . al - though growing evidence has shown the advantages of buttonhole cannulation , a generally accepted method of cannulating for the avf has not been defined yet . in theory , patients with buttonhole cannulation show fewer complications in the view of access , since buttonhole cannulation only needs one puncture site on the blood vessel wall and there is no regional injury of the elastic fiber on the blood vessel , thus reducing the incidence of aneurysm formation and vascular stenosis . on the one hand , the angle , direction and depth of cannulation must be identified before the formation of a buttonhole . however , even if the most skilled expert cannulators perform the procedure , slight or even invisible cannulation differences still exist between different operators or between several procedures performed by the same cannulator . on the other hand , in buttonhole cannulation , however , dry weight changes and variations in the patient 's fluid status , both intra- and extravascular , may lead to changes that render the cannulation more uncertain , illustrating the difficulty of punctuation . to make some progress in reducing the incidence of vascular access complications caused by buttonhole cannulation , ball   strongly recommended that the same expert should create the tunnels in order to maintain the same angle and depth to the greatest extent . one of them is to leave approximately 1/16 inch of the needles exposed when inserting them into the buttonhole tunnels to prevent the hub of the needles from touching the entrance sites , thus making it easy to punctuate , remove the scabs , clean the entrance site , and reduce the risk of injury and infection of the tunnel . the complications induced by buttonhole cannulation itself are sometimes difficult to be separated . unfortunately , in this case , recirculation monitoring was only applied 2 months before cannulation , so the exact time of abnormal fistula formation in this patient could not be known . in this rare case , edema on the left forearm and insufficient blood flow of the fistula revealed recirculation , abnormal fistula , and thrombus in the previous aneurysmal dilatation , which was confirmed by the transonic hd02 monitor and ultrasound . appropriate monitoring and surveillance for the detection of abnormalities concerning vascular access in dialysis patients is essential even under the best protection measures and the most skilled experts . the nkf - kdoqi work group recommends an organized monitoring or surveillance approach with regular assessment of clinical parameters of the vascular access . the detection of the access dysfunction contains three aspects : monitoring , surveillance , and diagnostic testing . monitoring is defined by the nkf - kdoqi as the evaluation of the vascular access by means of physical examination to detect physical signs that suggest the presence of dysfunction , which can be used as a monitoring tool to exclude low blood flow associated with impending vascular access failures . inspection ( look ) , palpation ( touch ) , and auscultation ( listen ) are three important components of monitoring , which can help clinical doctors detect initial events of vascular access . surveillance is an effective method to detect the presence of dysfunction by means of tests or even with special instruments . surveillance methods   include device - based methods such as sequential access flow , recirculation measurements ( recommended every month ) , sequential dynamic or static pressures , and so on . in the case described , ultrasound dilution , which is a practical , noninvasive and reliable indicator of vascular access , was used for function surveillance of the avf , which is reflected by access flow ( qa ) and recirculation . recirculation surveillance by ultrasound dilution thus not only indicates the existence of vascular stenosis but also other complex vascular complications . every 3 months , transonic hd02 monitor was scheduled for patients at our center , since it is not covered by insurance . for patients with a high risk of vascular access dysfunction as our case , such monitor sessions should take place every month . in the view of the dialysis adequacy and kt / v , on line urr based on uv absorbance may be a more sensitive method to find the inadequate dialysis in real time . however , no significant evidence has been found to prove prolonged access survival . although surveillance did not increase the likelihood of vascular access survival , it is critical to establish a team consisting of the patient , dialysis staff , vascular access coordinator , nephrologists , interventionalists , and vascular surgeon to take care of and improve the quality and outcomes of vascular access using monitor and surveillance . a well - functioning avf is the key to long - term maintenance hemodialysis in patient with esrd . however , one of the major causes of dialysis inadequacy is the dysfunction of vascular access resulting from vascular access complications . buttonhole cannulation compared to other cannulation methods is a technique that may lead to a reduction in many complications , but it can not entirely avoid all incidences of vascular access problems . therefore , before the formation of a buttonhole , the punctuation should be operated by a defined expert cannulator team to ensure that the identified angle , direction , and depth are maintained as well as possible and to pay attention to other details to minimize the incidence of complications as described above . a successful surveillance system should be established , including the participation of patients and medical staff from various departments based on the adequate monitoring , online kt / v monitor , and the surveillance of the vascular access with access blood flow and recirculation to identify a possible dysfunction of the avf . regular surveillance with the ultrasound dilation method before and during the process of construction of buttonhole cannulation is suggested to find a possible dysfunction of the avf so that intervention measures can be taken at the earliest convenience .