Renal stone disease in spinal-cord-injured patients

Renal stone disease is common among patients with spinal cord injury (SCI). They frequently have recurrent stones, staghorn calculi, and bilateral stone disease. The potential risk factors for stones in the SCI population are lesion level, bladder management strategy, specific metabolic changes, and frequent urinary tract infections. There has been a reduction in struvite stones among these patients, likely as a result of advances in their urologic care. The clinical presentation of stone disease in patients with SCI may involve frequent urinary infections or urosepsis, and at the time of presentation patients may need emergency renal drainage. The proportion of patients who have their stones treated with different modalities is largely unknown. Shockwave lithotripsy (SWL) is commonly used to manage stones in patients with SCI, and there have been reports of stone-free rates of 50% to 70%. The literature suggests that the morbidity associated with percutaneous nephrolithotomy in these patients is considerable. Ureteroscopy is a common modality used in the general population to treat patients with upper tract stone disease. Traditional limitations of this procedure in patients with SCI have likely been overcome with new flexible scopes; however, the medical literature has not specifically reported on its use among patients with SCI.     

Factors influencing bladder stone formation in patients with spinal cord injury

OBJECTIVE: Bladder stones that form in patients with spinal cord injury (SCI) can cause significant morbidity. This study sought to analyze factors associated with bladder stone formation to determine which patients might be at increased risk to develop bladder stones. METHODS: A review of 56 SCI patients treated for bladder calculi over a 10-year period at a single institution was performed. These patients were compared with a control population of general SCI patients known to be stone free. The factors compared were patient age, duration of injury, level of injury, completeness of injury, method of bladder management, and the presence of documented urinary tract infections with urease-producing organisms. RESULTS: All patients with stones were male and had a median age of 58.5 years. The median level of injury was C6, the median time since injury was 21 years, 66% had complete injuries, 68% managed their bladders with indwelling catheters or suprapubic tubes, and 83% had a history of infections with urease-producing organisms. When compared with the control group, patients forming bladder stones were older (P = 0.03), were more likely to have indwelling catheters (P < 0.0001), had a history of infections with urease-producing organisms (P = 0.04), and had complete injuries (P = 0.018). CONCLUSION: This information can be used to identify patients who have an increased risk of bladder stones and measures can be taken to reduce their incidence and morbidity.     

Proteus bacteriuria is associated with significant morbidity in spinal cord injury

STUDY DESIGN: Retrospective chart review. OBJECTIVES: We investigated the morbidity associated with Proteus bacteriuria in a spinal cord injured (SCI) population. SETTING: Michael E DeBakey Veterans Affairs Medical Center in Houston, Texas, USA. METHODS: We reviewed the medical records of all veterans with SCI who received care in our medical center during the past 3 years. Proteus bacteriuria was defined as the growth of Proteus species in any urine culture during the study period. Urinary stones were defined as either renal or bladder calculi. RESULTS: During the study period, 71 of the 501 subjects (14%) had Proteus and 90 (18%) had urinary stones. Twenty-seven percent of the subjects with Proteus had stones, and the association of Proteus with stones was significant (P<0.05). Proteus bacteriuria was likewise associated with complete injury, hospitalization, decubitus ulcers, and history of stones (P<0.001). Subjects using indwelling catheters, either transurethral or suprapubic, were significantly more likely to have Proteus, whereas subjects practising spontaneous voiding and clean intermittent catheterization were significantly less likely to have Proteus. In the 90 patients with stones, Proteus was associated with requiring treatment for stones and having multiple stones (P<0.01). Twenty-five of the 90 patients with stones (28%) required treatment, most often with lithotripsy, and 6 (7%) developed urosepsis. CONCLUSIONS: In persons with SCI, Proteus was found in subjects with a greater degree of impairment who were more likely to be hospitalized, to have decubiti, and to use indwelling catheters. Bacteriuria with Proteus predicted urologic complications in persons with SCI. STATEMENT OF ETHICS: All applicable institutional and governmental regulations concerning the ethical use of human volunteers were followed during the course of this research.     

Chronic suprapubic catheterization in the management of patients with spinal cord injuries: analysis of upper and lower urinary tract complications

OBJECTIVE

To assess whether chronic suprapubic catheterization (SPC) in patients with spinal cord injury (SCI) is associated with a higher incidence of significant urinary tract complications than in patients whose urinary tracts are managed by other methods.

PATIENTS AND METHODS

Our experience suggested that the incidence of complications in patients with SCI and SPC was acceptable and relatively low. Between 1988 and 2001, 1018 patients were admitted to our unit after SCI; 149 were managed by SPC and we retrospectively reviewed them, with a mean follow‐up of 6 years. There were no complications in 49% of patients. Most complications were minor (urinary tract infection 27%, bladder stones 22%) and were easily managed. Only 20 patients had upper tract complications. Nine patients had renal scarring and 14, all quadriplegic, had upper tract calculi. One patient developed well‐differentiated superficial transitional cell bladder cancer.

CONCLUSIONS

Patients with SCI often prefer SPC than other methods offered to them, because of quality‐of‐life issues. The incidence of significant complications might not be as high as previously reported, and with a commitment to careful follow‐up, SPC can be a safe option for carefully selected patients if adequate surveillance can be ensured.     

BLADDER LEAK POINT PRESSURE: THE MEASURE FOR SPHINCTEROTOMY SUCCESS IN SPINAL CORD INJURED PATIENTS WITH EXTERNAL DETRUSOR-SPHINCTER DYSSYNERGIA

Purpose

Transurethral resection of the external sphincter in patients with spinal cord injury and detrusor-external sphincter dyssynergia has high failure and reoperation rates. Retrospectively we examined elevated bladder leak point pressure after transurethral resection of the external sphincter as an indicator of failure.

Materials and Methods

A total of 55 spinal cord injury patients (mean age 50 years) underwent 1 or more sphincter resections, most recently a mean of 11 years ago. We reviewed the most recent urodynamic studies for bladder leak point pressure, bladder compliance and persisting external detrusor-sphincter dyssynergia. Each patient was assessed for the presence of an indwelling catheter, upper tract damage, stones, bacteriuria, autonomic dysreflexia and vesicoureteral reflux. The incidence of each of these urodynamic and clinical parameters among patients with bladder leak point pressure less than 40 cm. water was compared to the incidence among those with bladder leak point pressure greater than 40 cm. water.

Results

Patients with bladder leak point pressure greater than 40 cm. water had a significantly higher incidence of upper tract damage (p = 0.021) and persisting external detrusor-sphincter dyssynergia (p = 0.00008). The incidence of an indwelling catheter was no different between patients with bladder leak point pressure less than and greater than 40 cm. water.

Conclusions

Bladder leak point pressure greater than 40 cm. water is a valid indicator of failure of transurethral resection of the external sphincter since there is a significantly higher incidence of upper tract damage and persisting external detrusor-sphincter dyssynergia in these patients. Patients with favorable urodynamic parameters after transurethral resection of the external sphincter but with indwelling catheters were poorly selected for this procedure. Furthermore, those without an indwelling catheter after transurethral resection of the external sphincter may still have adverse urodynamic parameters and are at significant risk for upper tract damage.     

Factors Influencing Bladder Stone Formation in Patients With Spinal Cord Injury

Abstract

Objective: Bladder stones that form in patients with spinal cord injury (SCI) can cause significant morbidity. This study sought dto analyze factors associated withbladder stone formation to determine which patients might be at increased risk to developbladder stones.

Methods: A review of 56 SCI patients treated for bladder calculi over a 10-year period at a single institution was performed. These patients were compared with a control population of general SCI patients known tobe stone free. The factors compared were patient age, duration of injury, Ievei of injury, completeness of injury, method of bladder management, and the presence of documentedurinary tract infections with urease -producing organisms.

Results: All patients with stones were male and had a median age of 5 8.5years. The median Ievei of injury was C6, the median time since injury was 21 years, 66% had complete injuries, 68% managed their bladders with in dwelling cathetersor suprapubic tubes,and 83% had a history of infections with urease-producing organisms. When compared with the control group, patients forming bladder stones were older (P = 0 .03), were more likely to have in dwelling catheters (P < 0.0001 ), had a history of infections with urease-producing organisms (P = 0 .04), and had complete injuries(P= 0 .018).

Conclusion: This information can be used to identify patients who have anincreased risk of bladder stones and measures can betaken to reduce their incidence and morbidity.     

Changing composition of renal calculi in patients with neurogenic bladder

PURPOSE: Renal calculi are a significant source of morbidity for patients with neurogenic bladder. Calculi from patients with NB have traditionally been composed primarily of struvite and carbonate apatite secondary to chronic urea-splitting bacteriuria. In the current era there have been great improvements in the urological rehabilitation of patients with NB. We defined the composition of renal calculi in a contemporary cohort of patients with NB due to spinal cord injury or myelomeningocele who underwent percutaneous nephrolithotomy. MATERIALS AND METHODS: We performed a retrospective evaluation of all patients with NB due to SCI or MM who underwent PNL between January 2002 and January 2005. RESULTS: A total of 32 patients with NB (14 with SCI, 18 with MM) underwent PNL in this period. Stones were infectious in etiology in 37.5% (12 struvite/carbonate apatite) and metabolic in 62.5% (1 uric acid, 2 calcium oxalate monohydrate, 2 brushite, 6 hydroxyapatite, 9 mixed hydroxyapatite/calcium oxalate). All patients with struvite calculi were infected with urea-splitting bacteria on preoperative urine culture. CONCLUSIONS: Patients with neurogenic bladder are traditionally thought to harbor infection related calculi. These data demonstrate that many contemporary patients will be found to have calculi of a metabolic etiology. Although patients with NB still have renal calculi, advances in urological treatment may have affected the composition of their calculi, as metabolic stones are becoming more commonly identified. When metabolic components are identified, stone activity may be attenuated with appropriate metabolic evaluation, pharmacological therapies and dietary modifications.     

THE ROLE OF OXYBUTYNIN IN SPINAL CORD INJURED PATIENTS WITH INDWELLING CATHETERS

Purpose

The long-term benefits of oral oxybutynin in spinal cord injured patients with indwelling catheters is unknown. We reviewed our experience with this population of men and present the results of our analysis.

Materials and Methods

A total of 109 male spinal cord injured patients at the Houston Veterans Affairs Medical Center have been treated with chronic indwelling catheters (80 transurethral and 29 suprapubic). Thirty-eight patients (35%) were identified as using oxybutynin on a regular basis. These patients were compared to those not using oxybutynin with regard to urodynamic parameters and upper tract deterioration. Specifically examined were bladder compliance, bladder leak point pressure, vesicoureteral reflux, hydronephrosis, urolithiasis, febrile urinary tract infections and serum creatinine greater than 2 mg./dl.

Results

The mean duration of indwelling catheter use was 11.9 years (12.4 without oxybutynin and 10.9 on oral oxybutynin). Of the 31 patients with normal compliance (greater than 20 ml./cm. water), 24 (77%) were using oxybutynin (p = 0.001). Bladder leak point pressures were abnormal (greater than 35 cm. water) in 5 of 32 patients (16%) on oxybutynin versus 34 of 60 (57%) without it (p <0.001). Hydronephrosis was present in 15 of 66 patients (23%) without oxybutynin versus 1 of 36 (3%) with oxybutynin (p = 0.009). Febrile urinary tract infections occurred in 4 of 35 patients (11%) versus 17 of 62 patients (27%) with or without oxybutynin, respectively (p = 0.077). No significant differences were found between the 2 groups with regard to reflux, renal scars, stones or elevated serum creatinine.

Conclusions

It appears that regular use of oxybutynin may be beneficial in spinal cord injured patients who require chronic indwelling catheters for bladder management. Our analysis reveals that patients who take oxybutynin regularly have better bladder compliance, lower bladder leak point pressures and less hydronephrosis. Until a prospective, randomized trial reveals contradicting outcomes, empiric use of oxybutynin in all spinal cord injured patients requiring chronic indwelling catheters seems justified.     

Accuracy of predicting bladder stones based on catheter encrustation in individuals with spinal cord injury

BACKGROUND: Bladder calculi are the second most common urological complication in those with spinal cord injury (SCI). Detection and removal of bladder stones are important to prevent possible complications. OBJECTIVE: To determine the accuracy of bladder stone detection based on catheter encrustation in asymptomatic individuals with SCI. DESIGN: Prospective cohort study. METHODS: Cystoscopy findings in persons with SCI who were noted to have catheter encrustation at the time of catheter removal for their scheduled cystoscopy were used in this prospective study. Indwelling catheters were examined for encrustation at the time of removal as they were being prepared for cystoscopy. Cystoscopy was performed, and the presence or absence of bladder stones was noted. MAIN OUTCOME MEASURES: Presence or absence of bladder stones detected with cystoscopy in those with precystoscopy catheter encrustation. RESULTS: Forty-nine individuals with indwelling catheters were evaluated. Overall, 17/49 (35%) individuals in this study had bladder stones. Catheter encrustation was noted in 13 patients. Of these 13 patients, 11 also had bladder stones. In other words, a positive result for catheter encrustation had a positive result for bladder stones 85% of the time. Thirty-six individuals had no catheter encrustation. Of these, 6 (16%) were found to have bladder stones. CONCLUSIONS: Encrustation of a catheter is highly predictive of the presence of bladder stones. This suggests that cystoscopy should be scheduled in a person undergoing a catheter change if catheter encrustation is noted.     

Urinary tract complications in spinal cord injury patients

The characteristics of urinary tract complications in a series of 202 spinal cord injury patients are described. Repeated urinary infection was the most usual problem. Upper urinary tract changes were detected in 61 patients (30%). 56 patients (28%) underwent bladder outlet surgery for problems with voiding. Urinary diversion was done to 8 patients (4%), and 12 (6%) were treated with permanent indwelling catheter or self-catheterization. The high incidence of bladder stones (29%) and urethral complications (14%) was regarded as due to indwelling catheterization at the early stage post-injury. Despite the high urinary tract morbidity, only one patient has so far died of renal failure.     

Bladder stones following SCI in the Sprague-Dawley rat

OBJECTIVE: To develop a spinal cord injury (SCI) animal model for the study of bladder stones and compare this model with a non-SCI animal model. METHODS: Small pieces of catheters were implanted into the bladders of Sprague-Dawley rats as a nidus for bladder stone formation. Three weeks later, the rats underwent an SCI surgery (SCI transection or sham SCI). Control rats had SCI surgery, but no catheters were implanted into their bladders. MAIN OUTCOME MEASURES: Bladder stone number, weight, and composition were determined in two groups of SCI and sham SCI animals: Group A (recent spinal shock: 2 weeks post-SCI/sham SCI surgery) and Group B (out of spinal shock: 3 weeks to 3 months post-SCI/sham SCI surgery). A chi2 test was used to compare the incidence of bladder stones in SCI vs sham SCI animals. A Student t test was used to compare the weight of bladder stones in the 2 groups. RESULTS: Group A (recent spinal shock): Of the 20 SCI rats, 8 (40%) had stones. None of the sham SCI rats with implanted catheters (n = 5) had stones (0%). Group B (out of spinal shock): All 6 of the SCI rats with implanted catheters had stones (100%). Of the 10 sham SCI animals with implanted catheters, 3 (30%) had stones. Stones were more common in the SCI rats than in the sham SCI rats (chi2(1) = 4.9, P < 0.05). The mean weight of the bladder stones in SCI rats (42.2 +/- 16.3 mg) was greater than that in sham SCI rats (5.4 +/- 1.5 mg) (P < 0.01). Group C (controls: SCI surgery, but no catheter implanted): At 3 weeks post-SCI, control rats had no stones (n = 7); control rats at 3 months post-SCI also had no stones (n = 9). Stone composition in the 3 sham SCI animals was calcium apatite (90%) and calcium oxylate (10%). In the 14 SCI rats, 10 had struvite stones (100%), 1 had struvite (70%) and carbonate apatite (30%) stones, 1 had brushite (100)% stones, and 2 had carbonate apatite (> 90%) stones. CONCLUSION: Bladder stones occurred earlier and more frequently and attained a larger size in SCI rats with catheters compared with sham SCI rats with catheters. There were no stones in SCI rats without catheter implants, even at 3-month follow-up. The bladder stone composition in SCI rats was similar to that in humans with SCI. The Sprague-Dawley rat model appears to be an excellent animal model for the study of bladder stones following SCI.     

LONG-TERM OUTCOME OF INCONTINENT ILEOVESICOSTOMY MANAGEMENT OF SEVERE LOWER URINARY TRACT DYSFUNCTION

PURPOSE: We evaluated the extended 5-year followup outcome of incontinent ileovesicostomy. MATERIALS AND METHODS: We reviewed the charts of 25 men and 13 women with a mean age of 44.9 years who underwent incontinent ileovesicostomy, including the original 23 patients whom we reported on in 1993. Mean followup was 52 months. We compared the incidence of complications before and after ileovesicostomy as well as long-term urinary tract status. RESULTS: Before ileovesicostomy the incidence of serious complications associated with an indwelling catheter was significant, including poor bladder compliance in 50% of cases, urosepsis in 45%, hydronephrosis in 21%, renal struvite calculi in 18%, urethrocutaneous fistula in 18%, autonomic dysreflexia in 13% and bladder calculi in 2%. After conversion to ileovesicostomy our data show that 83 to 91% of this high risk population maintained a normal upper urinary tract and normal bladder storage compliance. CONCLUSIONS: Compared with preoperative status the incidence of postoperative complications was relatively low and they were readily corrected. Ileovesicostomy is an excellent long-term management solution for severe lower urinary tract dysfunction in patients who are unable to perform intermittent self-catheterization.     

Accuracy of bladder stone detection using abdominal x-ray after spinal cord injury

BACKGROUND: Bladder calculi are a common problem in those with spinal cord injury (SCI). Detection is important to prevent complications. OBJECTIVE: To determine the accuracy of bladder stone detection by abdominal x-rays. METHODS: X-ray reports from individuals with SCI with known bladder stones detected by cystoscopy were reviewed. MAIN OUTCOME MEASURES: X-ray reports noted the presence or absence of bladder stones. The stone variables evaluated were stone composition (crystallographic analysis), widest dimension of the largest stone (during cystoscopy), and the total volume (cm3) of the stone mass removed. RESULTS: Sixty-two consecutive x-ray reports from individuals with bladder stones were reviewed. The majority of stones were calcium phosphate (46.8%) or struvite (26.7%). Regarding stone composition, the detection by x-ray was 28.6% for struvite stones and 41.9% for calcium phosphate stones. Regarding diameter of largest stone, the detection by x-ray was 14% for stones < 0.5 cm, 0% for stones 0.5 cm to 0.9 cm, 33% for stones 1.0 cm to 1.49 cm, 33% for stones 1.5 cm to 1.9 cm, and 54% for stones > or = 2.0 cm. Regarding total volume of stones, the detection by x-ray was 0% for volumes < 0.2 cm3, 33% for volumes 0.2 cm3 to 0.39 cm3, 60% for volumes 0.40 cm3 to 0.59 cm3, 40% for volumes of 0.60 cm3 to 0.79 cm3, 0% for stones from 0.8 cm3 to 0.99 cm3, and 57% for volumes > or = 1.0 cm3. Overall, 13/62 (20.97%) of stones found during cystoscopy were detected by the x-ray. CONCLUSION: Abdominal x-ray is not a reliable method to detect bladder stones in individuals with SCI.     

Differences in bladder compliance with time and associations of bladder management with compliance in spinal cord injured patients

PURPOSE: Controversy continues on the optimal method of bladder management in spinal cord injured patients. We investigated the effects of bladder management on bladder compliance and changes in compliance with time. MATERIALS AND METHODS: We retrospectively reviewed the charts, and video urodynamic and upper tract radiographic studies of 316 patients with spinal cord injury. Patients were categorized according to interval since injury and bladder management method, including clean intermittent catheterization, spontaneous voiding and chronic Foley catheterization. Those with upper tract complications were compared with asymptomatic controls at the bladder compliance threshold values of 10.0, 12.5, 15.0 and 20.0 cc/cm. water. RESULTS: No significant differences were noted among bladder management method groups for followup, level, completeness or mechanism of injury. A bladder compliance threshold of 12.5 cc/cm. water was selected for the remaining comparisons based on the frequency of complications compared with asymptomatic controls. Patients using intermittent catheterization had a significantly higher incidence of normal compliance than the Foley management group for suprasacral, complete and incomplete injury (p<0.01). Normal bladder compliance was more common in patients with suprasacral than sacral and incomplete than complete spinal cord injury for each bladder management type. Logistic regression analysis of compliance versus bladder management and age of injury (interval since injury) revealed that intermittent catheterization and spontaneous voiding were associated more with normal compliance than Foley catheterization (RR = 9.2, 5.4 and 1.0, respectively). Combined data showed that each successively older age of injury cohort was at 23% greater risk for loss of normal compliance than the preceding cohort. Low compliance was statistically associated with vesicoureteral reflux, radiographic upper tract abnormality, pyelonephritis and upper tract stones (p<0.01, <0.01, 0.04 and <0.01, respectively). CONCLUSIONS: Clean intermittent catheterization protects bladder compliance in spinal cord injured patients regardless of the level or completeness of injury and helps to prevent low compliance with time. Also, in the population studied low compliance was associated with upper tract complications. Therefore, clean intermittent catheterization is the superior method for preserving bladder compliance and preventing the upper tract complications associated with low compliance.     

Bladder cancer in patients with spinal cord injury

OBJECTIVE: The incidence of bladder cancer in spinal cord injury (SCI) is 16 to 28 times higher than that in the general population. The objective of this study was to investigate the characteristics of bladder cancer that are unique to the SCI population. DESIGN: Retrospective review. METHODS: The charts of 16 patients diagnosed with bladder cancer from 1982 to 2001 were reviewed for type of cancer, exposure to risk factors, presenting symptoms, and survival time. RESULTS: The presenting manifestations were gross hematuria in 14 patients, papillary urethral growth in 1 patient, and acute obstructive renal failure in 1 patient. The diagnosis was made on initial cystoscopic evaluation in 16 patients; 3 patients required further evaluation. Eight of the 11 screening cytologies were suspicious for a malignancy prior to the diagnosis. Seven patients had transitional cell carcinoma, 6 patients had squamous cell carcinoma (SCCA), and 3 patients had both. The bladder wasmanaged with chronic indwelling catheter in 12 patients. Nine patients died of bladder cancer metastases and the remaining 3 patients died of other causes. Six patients survived 5 years or more; 4 were still alive at the completion of this study. CONCLUSION: Gross hematuria in individuals with SCI warrants aggressive assessment for bladder cancer. Chronic indwelling catheter, smoking, and renal and bladder stones are important risk factors for cancer. The incidence of SCCA in the SCI popullation is much higher than in the general population. Cystoscopic and cytologic evaluation in patients with advanced disease may fail to confirm the diagnosis in a high proportion of patients.     

Complications of the upper urinary tract in patients with spinal cord injury: a long-term follow-up study

The aim of this study was to establish hazard ratios for the risk of complications of the upper urinary tract in relation to bladder management methods in patients with spinal cord injury. A total of 179 male patients were eligible for this investigation which was followed-up on a yearly basis until 2003. The average age at which the lesion occurred was 25.2 years (range 18–57). The average duration of follow-up since SCI was 29.3 years (range 10–53). During follow-up, the incidence of vesicoureteral reflux (VUR) was 15.1%. A total of 61 (34.1%) and 44 (24.6%) patients were diagnosed with pyelonephritis and renal stones, respectively. There were no significant differences in these complications among groups. Upper tract deterioration (UTD) was observed in 58 patients (32.4%). The incidence of UTD in the urethral catheter group (51.7%) was higher than that in other groups (P=0.008). Using multivariate analysis, patients with VUR were shown to have a higher risk of pyelonephritis (odds ratio 2.78; 95% confidence interval 1.16–6.68), and UTD (odds ratio 22.10; 95% confidence interval 6.92–70.56). We also found that UTD was more common for patients with an indwelling urethral catheter than for patients using other methods. For other variables, no positive association was observed. In cases which cannot undergo intermittent catheterization, or when the bladder cannot empty spontaneously, a suprapubic catheter is better than a urethral catheter for reducing UTD in this population. These findings suggest that even at a late stage post injury, bladder management methods are still important.     

Bladder Stones Following Sci In The Sprague-Dawley Rat

Abstract

Objective: To develop a spinal cord injury (SCI) animal model for the study of bladder stones and compare this model with a non-SCI animal model.

Methods: Small pieces of catheters were implanted into the bladders of Sprague-Dawley rats as a nidus for bladder stone formation. Three weeks later, the rats underwent an SCI surgery (SCI transection or sham SCI). Control rats had SCI surgery, but no catheters were implanted into their bladders.

Main Outcome Measures: Bladder stone number, weight, and composition were determined in two groups of SCI and sham SCI animals: Group A (recent spinal shock: 2 weeks post-SCI/sham SCI surgery) and Group B(out of spinal shock: 3 weeks to 3 months post-SCI/sham SCI surgery). AX2 test was used to compare the incidence of bladder stones in SCI vs sham SCI animals. AStudent t test was used to compare the weight of bladder stones in the 2 groups.

Results: Group A(recent spinal shock): Of the 20 SCI rats, 8 (40%) had stones. None of the sham SCI rats with implanted catheters (n = 5) had stones (0%). Group B(out of spinal shock): All 6 of the SCI rats with implanted catheters had stones (100%). Of the 10 sham SCI animals with implanted catheters, 3 (30%) had stones. Stones were more common in the SCI rats than in the sham SCI rats (X²., = 4.9, P < 0.05). The mean weight of the bladder stones in SCI rats (42.2 ± 16.3 mg) was greater than that in sham SCI rats (5.4 ± 1.5 mg) (P < 0.01). Group C (controls: SCI surgery, but no catheter implanted): At 3 weeks post-SCI, control rats had no stones (n = 7); control rats at 3 months post-SCI also had no stones (n = 9). Stone composition in the 3 sham SCI animals was calcium apatite (90%) and calcium oxylate (10%). In the 14 SCI rats, 10 had struvite stones (1 00%), 1 had struvite (70%) and carbonate apatite (30%) stones, 1 had brushite (100)% stones, and 2 had carbonate apatite (>90%) stones.

Conclusion: Bladder stones occurred earlier and more frequently and attained a larger size in SCI rats with catheters compared with sham SCI rats with catheters. There were no stones in SCI rats without catheter implants, even at 3-month follow-up. The bladder stone composition in SCI rats was similar to that in humans with SCI. The Sprague-Dawley rat model appears to be an excellent animal model for the study of bladder stones following SCI.

J Spinal Cord Med. 2003;26:65-68     

Urinary calculi following traumatic spinal cord injury

OBJECTIVE: To investigate the time aspect of the development of renal and bladder calculi in individuals with traumatic spinal cord injury (SCI) and a possible relation between the development of calculi and the bladder-emptying method. MATERIAL AND METHODS: The study comprised a retrospective data collection from medical records and a questionnaire follow-up at least 10 years after the SCI. RESULTS: A total of 236 individuals with SCI (82% male, 18% female; 47% tetraplegic, 53% paraplegic) who were injured between 1956 and 1990 participated in the study and the response rate was 84.6%. The mean age at the time of follow-up was 50.5 years (range 28-84 years). The mean duration from the time of SCI was 24.1 years (range 10-45 years). During follow-up 47 participants (20%) had at least one episode of renal calculi and 32 (14%) had at least one episode of bladder calculi. The risk of first renal and bladder calculus was highest within the first 6 months post-injury. The cumulative proportion of calculi-free participants 45 years post-injury was 62% for renal calculi and 85% for bladder calculi. For participants who did not develop renal calculi within the first 2 years post-injury, the risk of having a renal calculus within the next 43 years was 34%. For bladder calculi the corresponding risk of having a bladder calculus within the next 43 years was 5%. No significant differences were found regarding the bladder-emptying method and either renal or bladder calculi, only a non-significant trend that more participants with bladder calculi used indwelling catheters. Participants with renal or bladder calculi were not statistically significantly different from the remainder of the study group regarding gender, para- or tetraplegia or Frankel classification. CONCLUSIONS: The risk of developing renal and bladder calculi was higher in the SCI population compared to the normal population. Bladder calculi primarily occur early post-injury and renal calculi appear both early post-injury and years later. Therefore, it is important to follow individuals with SCI regularly by means of urological investigations from the time of the injury until death.     

Urological situation five years after spinal cord injury.

OBJECTIVE: To evaluate bladder emptying methods and urinary tract problems five years after spinal cord injury (SCI). MATERIAL AND METHODS: Neurological level, method of bladder emptying and urological investigations were retrieved from the records for all 165 patients admitted to our Centre for Spinal Cord Injured with a traumatic SCI sustained from 1984 to 1988. RESULTS: A total of 77 patients with completed 5-year control were included in the final analyses. We found that 64% had suprasacral bladder dysfunction, while 23% had infrasacral bladder dysfunction. Plasma-creatinine was normal, both at the initial examination and the 5-year control. From the time in the SCI centre to the 5-year control a trend towards less intermittent catheterization and more use of abdominal pressure was observed. During the follow-up period nine patients (12%) experienced urinary calculi. Six bladder- stones were removed endoscopically. Five had kidney stones; three were left untreated, one was removed by extracorporeal shock wave lithotripsy and one by open surgery. Four patients (5%) had renograms with functional distribution outside the limits 40-60%. Three patients had bladder neck incision performed, one had a sacral anterior root stimulator implanted and one had a continent Kock reservoir. No sphincterotomies were performed. Fifty-one had received medicine to facilitate bladder emptying. Eighty-one percent had been treated for at least one urinary tract infection (UTI), 22% had 2-3 UTI/year, and 12% 4 or more UTI/year. Twelve percent had been on prophylactic low-dose antibiotics. CONCLUSION: The final outcome regarding urological complications is satisfactory even with our conservative handling of the SCI individuals.     

Risk Factors for Bladder Tumors in Spinal Cord Injury Patients

Purpose

We evaluated risk factors for the development of bladder tumors in spinal cord injury patients.

Materials and Methods

A retrospective review was done of all bladder tumors at 1 institution with matched controls for 7 years.

Results

We identified 17 malignant and 2 benign tumors. Indwelling bladder catheters and a history of bladder stones were statistically significant risk factors. Four patients with negative biopsies underwent repeat biopsy due to suspicious cytology and cancer was found.

Conclusions

An indwelling urinary catheter and a history of bladder stones are statistically significant risk factors. Cytology and biopsy are complementary in the evaluation of urothelial malignancy in this population. A high index of suspicion and thorough evaluation are needed in spinal cord injury patients.