Urolithiasis DOI 10.1007/s00240-015-0786-0

ORIGINAL PAPER

Flexible ureteroscopic for upper urinary tract stone in patients with spinal cord

Abdulkadir Tepeler1 · Brian C. Sninsky1 · Stephen Y. Nakada1

Received: 12 January 2015 / Accepted: 12 May 2015 © Springer-Verlag Berlin Heidelberg 2015

Abstract The objective of this study is to present the (n: 1) were common abnormalities in 24-h outcomes of flexible ureteroscopic (URS) analysis. Ureteroscopic laser lithotripsy can be an for upper urinary tract stone disease in effective treatment modality for SCI patients with upper (SCI) patients performed by a single surgeon. A retrospec- urinary tract calculi. tive analysis was performed for SCI patients treated with flexible URS for proximal and stone disease Keywords Spinal cord injury · Urolithiasis · by a single surgeon between 2003 and 2013. Patient char- · Laser lithotripsy acteristics, operative outcomes, metabolic evaluation, and stone analyses were assessed in detail. A total of 27 URS procedures were performed for urolithiasis in 21 renal Introduction units of 19 patients. The mean age was 52.1 15.6 years ± (16–72) and mean BMI was 29.2 7.3 kg/m2 (20–45.7). Spinal cord injury (SCI) causes neurologic problems ± Etiology of SCI was trauma (n: 10), multiple sclerosis (n: including deterioration of sensorial, motor and autonomic 6), cerebrovascular accident (n: 1), or undetermined (n: 2). functions, leading to restricted physical activity, bladder The mean stone size was 15.9 8.6 (6–40) mm. In the and bowel dysfunction, and metabolic alterations. Previous ± 27 URS procedures, stones were located in the ureter (n: studies report that this patient group has an increased risk 5), the kidney (n: 14), and both areas (n: 8). Mean hospi- of urolithiasis compared to the general population [1–4]. talization time was 2.0 2.4 (0–10) days. Postoperative In the study with longest follow-up period, the percentage ± complications were observed in 6 cases (22.2 %). Three of SCI patients with renal calculi was reported to be 38 % major complications included urosepsis (n: 1) and res- [3]. of urolithiasis peaks approximately 6 months piratory failure (n: 2), that were observed postoperatively after onset of SCI [4, 5]. and required admission to the intensive care unit. The 2 Due to improvements in equipment and experience, minor complications were hypotension, fever and UTI, minimally invasive methods are now a reasonable choice of and required medical treatment. Fourteen (66.6 %) of the surgical treatment in SCI stone patients. However, the treat- 21 renal units were stone free. car- ment of urolithiasis in this group of patients still present bonate (n: 9) and (n: 5) were the primary stone challenges for even the most experienced endourologists. compositions detected. Hypocitraturia (n: 6), hypercalci- The main factors complicating treatment of urolithiasis in uria (n: 5), hypernaturia (n: 5), (n: 4), and SCI patients include (1) an increased risk of (UTI) and urosepsis related to neurogenic blad- der dysfunction, (2) patient positioning difficulties related * Abdulkadir Tepeler to contracture of the extremities, and (3) risks secondary [email protected] to accompanying co-morbidities. The literature contains a limited number of studies presenting the outcomes of ure- 1 Department of , University of Wisconsin School of Medicine and Public Health, 1685 Highland Avenue, 3rd teroscopy (URS) [6, 7] or percutaneous nephrolithotomy Floor, Madison, WI 53705, USA (PNL) [7–12] in this specific patient group.

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In this study, we present the outcomes of flexible URS stone burden were re-evaluated radiologically to determine monotherapy for upper urinary tract stone disease in SCI the need for additional treatment session. Patients with patients performed by single surgeon. residual stone fragments <3 mm were considered a surgical success. A 24 h urine analysis was collected at follow-up.

Materials and methods Results A retrospective analysis was performed for SCI patients treated with flexible URS for upper urinary tract stone dis- A total of 27 flexible URS procedures were performed ease by a single surgeon between 2003 and 2013. Patient for urolithiasis in 21 renal units of 19 patients. The mean characteristics (age, sex, BMI, etiological factors, level of age was 52.1 15.6 years (16–72), and mean BMI was ± injury, co-morbidities, bladder management method, uri- 29.2 7.3 kg/m2 (20–45.7). Etiology of SCI was trauma ± nary tract infection and urosepsis, and stone size and loca- (n: 10), multiple sclerosis (n: 6), cerebrovascular acci- tion), operative outcomes (hospitalization time, and rates of dent (n: 1), or undetermined (n: 2). Thirteen patients success, complications and additional treatment), and meta- were paraplegic, while the remaining six were quadri- bolic evaluation and stone analyses were assessed in detail. plegic. Co-morbidities accompanying SCI included dia- betes mellitus (n: 5), (n: 4), (n: 3), Pre-operative evaluation coronary artery disease (n: 1), hypotiroidi (n: 1), conges- tive heart failure (n: 1), short gut syndrome (n: 1), epi- Routine laboratory and radiological work-up was done for lepsy (n: 1), and depression (n: 1). While twelve of the all patients. Urine cultures were obtained prior to surgery, patients had a history of UTI, 4 cases had urosepsis and and those with positive urine cultures were treated with cul- 17 had urinary stone disease previously. The mean stone ture-specific agents. All patients were evaluated with com- size was 15.9 8.6 (6–40) mm. The longest stone size ± puted tomography to assess the stone size and location and was calculated as 4 cm in a patient with multiple stones grade of . Stone size was determined as the located in the upper ureter and kidney. In the 27 URS longest size or sum of the stone sizes. Patients with severe procedures, stones were located in the proximal ureter obstructive hydronephrosis were initially treated with the (n: 5), the kidney (n: 14), and both areas (n: 8). Repeated insertion of a ureteral J prior to the URS procedure. sessions of URS was performed in cases with stone re- growth (n: 1), persistent stone (n: 5), and recurrent new Operative technique stone (n: 2). Patient demographics are summarized in Table 1 and Table 2. All procedures were performed under general , in No intraoperative complications occurred during any consideration of patient factors and the anesthesiologist’s of the procedures. A ureteral J stent was placed at 24 of preference. Depending on the presence of lower extrem- 27 procedures. Mean hospitalization time was 2.0 2.4 ± ity contractures, the procedure was done with the patient (0–10) days. Postoperative complications were observed in either a supine or position. After detailed cys- in 6 cases (22.2 %). Hypotension (Clavien grade 1), fever toscopy and insertion of a guide-wire through the ureteral (Clavien grade 1), and UTI (Clavien grade 2) were minor orifice, a flexible ureteroscope was passed over the guide- complications requiring medical treatments. Urosepsis (n: wire up to the upper tract using fluoroscopic guidance. 1) (Clavien grade 4) and respiratory failure (n: 2) (Cla- Stone fragmentation was performed using a 200 or 270 µ vien grade 4) were observed postoperatively and required Ho:YAG laser fiber at 0.8 Hz/8 J. The stone fragments were admission to the intensive care unit. The success rate after left in situ for spontaneous passage. At the end of the pro- a single procedure was 57.1 %. After additional sessions of cedure, placement of a ureteral J stent was based on sur- URS (n: 6), 14 (66.6 %) of the 21 renal units were stone geon preference. free. The outcomes are summarized in Table 3. Information about stone analysis and/or metabolic eval- Postoperative follow-up uation was available in 14 of the patients. Calcium phos- phate carbonate (carbonate-) was the most common Postoperative complications were graded according to the (n: 9) stone composition detected. ammonium modified Clavien system [13]. Patients were routinely eval- phosphate (struvite) was detected in 5 cases. The main uated with imaging (US, KUB, and/or CT) to assess stone abnormalities detected in the 24-h urine analysis were clearance. Stone analysis and metabolic work-up were done hypocitraturia (n: 6), (n: 5), hypernaturia (n: during the postoperative period. Patients with a residual 5), hyperoxaluria (n: 4), and hyperuricosuria (n: 1).

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Table 1 Patient demographics Discussion Number of patients 19 SCI patients represent a unique group that is associated Number of procedure 27 with multiple co-morbidities, and increased risk of mor- Mean age (years) 52.1 15.66 (16–72) ± tality and postoperative complication rate [1–12, 14]. The Mean BMI (kg/m2) 29.2 7.3 (20–45.7) ± most serious urologic complications of SCI and neurogenic Male/Female 11/8 bladder dysfunction include the formation of vesicoureteral Etiology reflux and hydronephrosis, renal failure, urolithiasis, UTI, Traumatic SCI 10 bladder cancer, and sexual dysfunction [15]. In a large MS 6 American cohort, the incidence of renal stones after SCI C VA 1 was reported as 8/1000 cases per year [2]. The same study Others (unknown) 2 estimated that renal stone formation occurs in 7 % of SCI Disabilities cases within 10 years of the injury. UTI, urinary stasis, Paraplegia 13 chronic catheterization, , immobiliza- Quadriplegia 6 tion, and hypercalcemia are all regarded as predisposing Level of the lesion factors for stone formation [16, 17]. Stone disease can lead Cerebral 7 to the loss of renal function if left untreated, and for this Cervical 4 reason, aggressive treatment and close follow-up are rec- Thoracic 7 ommended in this specific group. Lumbosacral 2 The treatment of urolithiasis in SCI patients is com- Medical comorbidities 19 plicated because of the increased risk of UTI and urosep- mellitus 5 sis, abnormal body habitus, and contractures or metallic Obesity 4 implants which can prevent proper positioning for treat- Hypertension 3 ment. Although shockwave lithotripsy is the least invasive Coronary artery disease 1 method, the success rate is only 44–55 % [18, 19]. This is Hypotiroidi 1 associated with the aforementioned considerations, as well Congestive heart failure 1 as reduced clearance of stone fragments resulting from Short gut syndrome 1 decreased mobility of SCI patients, impaired peristalsis of Epilepsy 1 the collection system, and increased stone size. For these Depression 1 reasons, endoscopic treatment modalities are a good treat- ment option in this population. With advances in endourologic therapy, PNL has Table 2 Parameters related to urologic history and examination become a commonly used technique for the management of History of urinary tract infection 12/19 (63.1 %) kidney stones. As surgeons gain experience, it can be used for even the most challenging cases. The literature contains History of urosepsis 4/19 (21.0 %) limited references to SCI patients treated with PNL [7–12]. History of urolithiasis 17/19 (89.5 %) PNL is a proper treatment modality for patients with a Bladder management methods large stone burden and staghorn renal calculi, as commonly Suprapubic catheter: 2 found in SCI patients. The success rate for a single PNL Indwelling urethral catheter: 3 session is between 53.8 and 62 % [7–12]. However, addi- Intermittent catheterization: 6 tional PNL sessions are reported to increase the stone-free Condom catheter: 3 rate up to 96 % [8]. In a recently published study, the suc- Diaper 1 cess rate after a mean of 2 PNL sessions in patients with Both (intermittent catheterization condom 2 catheter) + an average of 31.3 mm renal stone burden was reported to Mean stone size (mm) 15.92 8.6 (6–40) be 88.5 % [9]. On the other hand, the complication rate of ± PNL is reported to be higher in SCI patients compared to Stone location in 27 procedures ambulatory patients, because of the increased comorbidi- Upper ureter 5 ties of SCI patients. The major complication rate reported Kidney 14 in the literature ranges from 7 to 20 % [8, 9, 11, 12]. Infec- Ureter and kidney 8 tious complications (urosepsis, perirenal abscess, and UTI),

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Table 3 Perioperative and postoperative outcomes are listed present study, 27 flexible URS procedures were performed in 21 renal units of 19 patients. The initial stone-free rate Hospitalization time (days) 2.0 2.44 (0–10) ± was 57.1 % and increased to 66.6 % with additional URS Complications 6/27 (22.2 %) (n: 6) sessions. Fever 1 Wolfe and associates reported complications in 29.9 % Hypotension 1 of the procedures in their study [6]. The most common UTI 1 complications were urosepsis (17.9 %), respiratory fail- Urosepsis 1 ure (4.5 %), and acute outlet obstruction (4.5 %). Clavien Respiratory failure 2 grade-5 (death) complication occurred in one patient due to Initial success 12/21 (57.1 %) urosepsis and respiratory failure. Chronic obstructive pul- Final success rate 14/21 (66.6 %) monary disease and incomplete motor SCI were found to be significantly related to increased complications. In the present study, complications were associated with only 6 respiratory arrest, pneumothorax, and bleeding are the (22.2 %) procedures. Two of these (urosepsis and respira- most common major complications reported [8, 9, 11, 12]. tory failure) required ICU admission. Preoperative urine Although PNL is considered the primary treatment option culture and appropriate treatment of UTI, bladder man- for large renal calculi, it has an increased complication risk. agement methods play an important role in prevention Therefore, URS should be considered as a less-invasive of urosepsis in this patient group. In this series, urosep- alternative therapy for non-bulky upper urinary tract stones sis occurred in a patient with positive urine culture. This in SCI patients. In the present study, the mean stone size patient was using only diapers for incontinence. was 15.9 8.6 mm, making URS the preferred treatment Limitations of the current study include its retrospec- ± modality. Although URS is generally recommended for tive nature, small sample size, lack of a comparison group non-bulky stones, in the presented series, multiple sessions with other treatment modalities (PNL or SWL), and lack of URS were applied in a patient with upper ureteral and of information about operation times. Despite these limita- kidney stones with the total size of 4 cm. tions, we believe that this study contributes to the literature As medical technology has improved, ureteroscopic for the selection of proper treatment modalities for urolithi- laser lithotripsy has become more popular for the treatment asis in SCI patients. of upper urinary tract calculi. Its minimally invasive nature and reduced risk of complications are the main advan- tages compared to PNL. The use of URS in SCI patients Conclusions is reported by two recently published studies [6, 7]. Welk et al. [7] evaluated 5121 patients who had experienced an SCI patients require dedicated multidisciplinary medical SCI in the previous 9 years and investigated surgical inter- care because of their accompanying comorbidities. Unfor- ventions for kidney stones. They reported 66 SCI cases tunately, treatment modalities for stone disease are associ- treated with 89 procedures, including PNL (n: 15), SWL ated with a higher complication and morbidity rate and a (n: 17), URS (n: 30), ureteral stent insertion (n: 14), and lower success rate compared to non-SCI patients. Uretero- percutaneous tube insertion (n: 13). The pri- scopic stone treatment was found to be an effective treat- mary limitations of this study were the lack of informa- ment modality for SCI patients with urinary tract calculi. tion about patient demographics, and absence of success and complication rates for each procedure. The authors Conflict of interest The authors declare that they have no conflict reported that 67 % of the URS cases required inpatient hos- of interest. pital admission after the procedure, with a mean hospital Disclosure statement No competing financial interests were stay of 5 days. The mean number of follow-up procedures declared. within 90 days of the primary URS was 2. In the second study, Wolfe et al. [6] evaluated 29 SCI patients treated with 67 URS sessions for urolithiasis over References a 15-year period. The mean URS sessions per patient were 2. The stones were located in the kidney, ureter, or multi- 1. Welk B, Fuller A, Razvi H, Denstedt J (2012) Renal stone dis- ple locations in 43 (64.2 %), 8 (12 %), and 16 (23.9 %) of ease in spinal-cord-injured patients. J Endourol 26(8):954–959 procedures, respectively. Stone-free status was achieved 2. Chen Y, DeVivo MJ, Roseman JM (2000) Current trend and risk factors for kidney stones in persons with spinal cord injury: a in 34.3 % of the cases. Failures were attributed to techni- longitudinal study. Spinal Cord 38(6):346–353 cal problems, such as inability of the ureteroscope to pass 3. Curhan GC (2007) Epidemiology of stone disease. Urol Clin through the ureteral orifice and access the stone. In the North Am 34(3):287–293

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