A strictdefinition for ” forgotten ” does not exist; however, many previous studiesconsider a variable period of greater than 3 to 6 months to constitute aforgotten stent 2. The causes of forgotten ureteral stents could beclassified as surgeon’s, patient’s, stent material and others factors; In abiochemical and optical analyses of stent encrustations by Robert et al.,they revealed that encrustations consisted mainly of calcium oxalate, calciumphosphate and ammonium magnesium phosphate 3,4.
Siliconecontaining stents tend to be more resistant to encrustation, followed bypolyurethane, silitek, percuflex and hydrogel coated polyurethane1.We use polyurethrane stents at our center. Poorcompliance from the patient side is the major concern, which leads to forgottenDJ stent in situ 5, and it is reflected in out study as well Okuda etal reported on 15 irremovable ureteral stents in Japanese patients. Themean indwelling times of these stents was 20 months 6.
In a study byRingel A et al, in total of 110 stented kidneys, they observed that the totalcomplication rate was up to 32.7% and in 8.2% of the cases, the stents had migrated7. In another study, Damiano R et al observed flank pain in 25.
3%,encrustations in 21.6%, irritative bladder symptoms in 18.8%, hematuria in18.1%, fever more than 104°F in 12.3% and stent migration in 9.5% of the patients8.
In our study, most common presenting complaints were LUTSfollowed by hematuria and flank pain. They also reported that longer durationof stent retention was associated with increased frequency of encrustations,infections, calculus formation and obstruction of the stented tract.The availableliterature shows that DJ stent had been missed for a maximum of 23 years 2;in our study the maximum duration was of 6 years.There isno pre-defined algorithm for the management of the forgotten DJ stents but itdepends on the site of encrustation, the size of the stone burden and thefunction of the affected kidney Management may often require multipleendourologic approaches and/or open surgeries.
Kane et al. in Senegalreported in a comparative study of 89 patients with upper urinary tract calculiwho underwent endourology intervention or open surgery. Less complication andearly discharge from hospital was observed in the endourology group 9.Lupu etal has described SWL as the noninvasive procedure of choice for calcifiedureteral stents. SWL successfully fragmented calcifications on the renal endand ureteral segment of the stent, but electrohydraulic lithotripsy wasnecessary to fragment calcification on the bladder end10. Forencrustations located at the upper coil and or stent body, ESWL and flexibleureteroscopy retrieval of the stent has been reported to be non-invasive andeffective first line therapy.
ESWL is however indicated mainly for localized,low volume encrustations 11,12. Flexible ureteroscopy with holmiumlaser lithotripsy is an alternative minimally invasive treatment option. Okeke etal.
13 and Papoola et al.14 eventually underwentsuccessful endoscopic retrieval of the stent material with no complications.In case of severe incrustations, management modalities are morecomplex.
Many investigators have employed ESWL, URS-Se, laser-lithotripsy,PCNL, chemolysis using various chemolytic agents administered via apercutaneous nephrostomy tube, and open surgery either alone or in combinationwith other procedures 15,16.Single procedure removal of encrusted stent has also been reported5, but it should be avoided for severely encrusted stents. In caseof long intraoperative time, over enthusiastic single-stage removal isdiscouraged, and it is better to stage the procedure 2.
Ecke and colleaguesproposed that distal part of the stone burden be removed first as it willfacilitate the placement of the ureteric access catheter and then PCNL could beused for the stone- covered proximal end of the stent 17.Tang VC etal studied the stent card system to track the retained DJ stent and haveproposed the computerized DJ stent registry and similarly Lynch M F et al intheir study showed the importance of electronic stent register and stentextraction reminder facility to avoid the DJ stent follow up loss and avoid themorbidity associated with it 18,19. McCahy et al. recommendedthat a computer record should be composed recording the patients that stent wasplaced in urology clinics and warning the urology physicians about the time ofremoval of stents 20. “Stents on strings” have been proposed whereone end of the stent is tied to a sting, which is externalized for easy removallater.
Prevention is the best form of treatment to avoid this complication.Oninteractive sessions, were found that the most common reason for the forgottenstent was lack of knowledge to the patient and the attendants for the same andit was seen in 13 patients. Of the rest 3 patients, two patients had forgottenthemselves and one was lost to follow up till the patient had recurrentcomplaints.