Long-term effectiveness of sacral nerve stimulation for refractory urge incontinence

OBJECTIVES: To evaluate the long-term efficacy of sacral nerve stimulation for refractory urinary urge incontinence. STUDY DESIGN AND METHODS: Urge incontinent patients qualified for surgical implantation of a neurostimulator system after trial screening with percutaneous test stimulation. Surgical implantation of the InterStim System (Medtronic Inc., Minneapolis, Minn., USA) was performed in cases where a >50% reduction in incontinence symptoms was documented during the 3- to 7-day test stimulation period. The InterStim System consists of an implantable pulse generator, a transforamenally placed quadripolar lead, and an extension that connects these two devices for unilateral stimulation of the S3 or S4 sacral nerve. Efficacy for 96 implanted patients was based on urinary symptom changes as quantified in voiding diaries collected at baseline and annually after surgical implantation. RESULTS: As compared to baseline, the group of 96 implanted patients demonstrated significant reductions in urge incontinent symptoms at an average of 30.8+/-14.8 (range 12-60) months with respect to the number of urge incontinent episodes per day, severity of leaking, and the number of absorbent pads/diapers replaced per day due to incontinence (all p<0.0001, respectively). Gender, pretreatment variables, and age were not found to be relevant factors that affected these results. 11 of the 96 patients underwent device explant due to lack of efficacy, pain or bowel dysfunction. These data were conservatively included in the efficacy results. No permanent injuries associated with the devices or therapy were reported. CONCLUSION: Sacral nerve stimulation is an effective treatment for refractory urge incontinence with sustained long-term benefit through an average of 30.8 months.     

Sakrale Neuromodulation in der Urologie

Sacral nerve modulation (SNM) is an innovative, minimally invasive treatment that uses chronic low-level electrical stimulation of the sacral plexus to recruit residual physiological function of urinary bladder detrusor, pelvic floor muscles, and the anorectal continence structures. Classic indications for sacral neuromodulation in urology are refractory overactive bladder symptoms (urinary urgency ± incontinence) and chronic nonobstructive urinary retention. SNM also offers a therapeutic alternative in refractory chronic pelvic pain syndrome. The exact mechanism of action is still unknown, but it is assumed that electrical stimulation of the sacral nerves leads to neuromodulation as well as clinically beneficial effects in the pelvic floor, the sphincter complex, and the distal colorectum. SNM is a multistep procedure. In a test phase of so-called percutaneous or peripheral nerve evaluation (PNE), the effect of sacral neuromodulation is evaluated over days or weeks during which a bladder diary/pain protocol is kept. The predictive value of PNE is high, while morbidity and surgical trauma are low. The screening phase provided by PNE makes this technique unique and offers an ideal instrument for patient selection. After final implantation of the neurostimulator (InterStim II), the long-term success rate is over 60–90%. At our clinic, 42 patients underwent a PNE procedure between January 2009 and June 2010. Of these, 34 patients had a >50% success rate and had been implanted with the InterStim II device (80.9%). The success rates were 83% for overactive bladder and 89% for chronic retention (mean follow-up 7.8 months). In addition to the surgical procedure, the exact indication and postoperative care are important prerequisites of successful therapy. To date, no information on the number of implanted stimulators in Germany is available. This suggests the need for establishment of a national prospective registry. It would also be appropriate that the experts from the implantation centers form a working group.     

Sacral neuromodulation for the treatment of refractory interstitial cystitis: outcomes based on technique

Patients with refractory interstitial cystitis (IC) underwent testing with sacral nerve modulation via either a traditional percutaneous approach or a staged procedure. Implanted patients were followed with scaled questionnaires and voiding diaries. Twenty-six patients who had a permanent InterStim placed had a reduction in 24-h voids of 51%. More than two-thirds of patients reported a moderate or marked improvement in urinary frequency, urgency, pelvic pain, pelvic pressure, incontinence and overall quality of life. The test to implant rate of a traditional percutaneous procedure was 52%, compared to a staged procedure of 94%. Assessing sensory response at the time of implant reduced the reoperation rate from 43% to 0%. Ninety-six per cent stated they would undergo an implant again and recommend the therapy to a friend. We concluded that sacral nerve modulation can treat refractory IC symptoms. The response to therapy and the reoperation rate are dependent on the technique used to test and implant the device.Abbreviations IC Interstitial cystitis - TENS Transcutaneous electrical nerve stimulation Editorial Comment: The authors nicely describe a very difficult subset of patients with interstitial cystitis. The patients in this paper have failed six prior treatment modalities before undergoing sacral neural modulation. In this small series the response to therapy and reoperation rate was dependent on the technique used to test and implant the device. Sacral neuromodulation using the staged technique does show significant benefit in the treatment of refractory interstitial cystitis.     

Predictors of success for first stage neuromodulation: motor versus sensory response

PURPOSE: We investigated whether intraoperative motor or sensory response is more predictive of successful sacral neuromodulation using the InterStim system. MATERIALS AND METHODS: A total of 35 patients with medically refractory frequency, urgency and urge incontinence were enrolled in the study. All patients underwent lead placement for quadripolar test stimulation under local anesthesia with intravenous sedation. Confirmation of correct lead placement was by observation of known motor and sensory responses that result from third sacral nerve stimulation. Motor and sensory responses were documented intraoperatively. Patients had a 1-week trial of stimulation, and those who had greater than 50% improvement in symptoms had placement of the implantable pulse generator. Those without at least 50% improvement in their symptoms had the quadripolar lead removed. RESULTS: Of the 35 patients enrolled 21 had successful quadripolar test stimulation and went on to permanent implantable pulse generator placement. Of the patients who had successful quadripolar test stimulation 95% demonstrated positive intraoperative motor response whereas only 21.4% of patients with unsuccessful quadripolar test stimulation demonstrated positive motor response. If only a positive sensory response was elicited, patients had only a 4.7% chance of having a positive quadripolar test stimulation. CONCLUSIONS: A positive quadripolar test stimulation (greater than 50% improvement in symptoms) with InterStim sacral neuromodulation is more likely when intraoperative lead placement results in positive motor response vs only sensory response.     

Sacral nerve stimulation in the treatment of bowel dysfunction from imperforate anus: A case report

IntroductionBowel dysfunction (fecal incontinence and constipation) presents in over 50% of patients after treatment of congenital anal malformations. Sacral nerve stimulation (SNS) for the treatment of fecal incontinence improves function in the majority of patients. We present a case report of the treatment of bowel dysfunction with sacral nerve stimulation in a patient with a history of an imperforate anus.Presentation of caseA twenty year-old female with a history of imperforate anus at birth, repaired during infancy with anorectoplasty, presented with fecal incontinence and constipation. Since childhood, she had been suffering from intermittent constipation with worsening fecal incontinence in early adulthood. Examination revealed mild anal stenosis and mucosal prolapse. Endoanal ultrasound demonstrated intact internal and external sphincter with low resting and squeeze pressures on anal manometry. Flexible sigmoidoscopy was normal. The patient underwent permanent sacral nerve stimulation with a primary goal of improvement in continence and, secondarily, for the alleviation of intermittent chronic constipation.DiscussionAt 15 month follow-up, the patient had improvement in fecal incontinence (CCIS of 14 pre-SNS to 1 post-SNS), constipation (CCCS of 28 pre-SNS to 20 post-SNS), and quality of life (FIQOL improved in lifestyle (3.7), coping/behavior (3.4), self perception (3.9), and social embarrassment (4.5).ConclusionSacral nerve stimulation for the treatment of bowel dysfunction in adults secondary to imperforate anus can be performed safely and with good results.     

Sacral nerve stimulation in the elderly

Sacral neuromodulation has become a widely accepted form of therapy in the overall spectrum of treatment options for urinary urgency and frequency, urge urinary incontinence, and some forms of nonobstructive urinary retention. Voiding dysfunction is very common in geriatric patients, and urgency and urge urinary incontinence are among the most prevalent forms of urinary problems in this population. Despite the fact that many different treatment options are available for these conditions, successful treatment of voiding problems in the elderly is often quite challenging. This may be exacerbated by underlying comorbidities which preclude or limit the utility of some therapies including medications. Published literature on the use and clinical outcomes of sacral nerve stimulation in older adults was reviewed and summarized. Available clinical studies examining the use of sacral neuromodulation in geriatric patients are reviewed and placed in the context of the overall treatment of voiding dysfunction in the elderly population. Sacral neuromodulation may represent a viable, minimally invasive treatment option for some older adults.     

Sacral nerve stimulation in the elderly

Sacral neuromodulation has become a widely accepted form of therapy in the overall spectrum of treatment options for urinary urgency and frequency, urge urinary incontinence, and some forms of nonobstructive urinary retention. Voiding dysfunction is very common in geriatric patients, and urgency and urge urinary incontinence are among the most prevalent forms of urinary problems in this population. Despite the fact that many different treatment options are available for these conditions, successful treatment of voiding problems in the elderly is often quite challenging. This may be exacerbated by underlying comorbidities which preclude or limit the utility of some therapies including medications. Published literature on the use and clinical outcomes of sacral nerve stimulation in older adults was reviewed and summarized. Available clinical studies examining the use of sacral neuromodulation in geriatric patients are reviewed and placed in the context of the overall treatment of voiding dysfunction in the elderly population. Sacral neuromodulation may represent a viable, minimally invasive treatment option for some older adults.     

Sacral neuromodulation for constipation and fecal incontinence in children

Sacral neuromodulation has become an established treatment option for adults with fecal incontinence, but has only been applied to children with defecatory disorders over the past decade. Unlike in adults, the primary cause of fecal incontinence in children is poorly controlled constipation. There is growing evidence that sacral neuromodulation can be effective in the treatment of children with both constipation and fecal incontinence refractory to conventional treatment, and sacral nerve stimulation appears to be a promising treatment for a population of children with limited treatment options and debilitating symptoms. However, both experience with this treatment modality and the quality of evidence for its use remain limited. Given the relatively high complication rate associated with sacral nerve stimulation, further research is needed before more widespread acceptance of this treatment in the management of children with refractory constipation and fecal incontinence.     

Efficacy of sacral nerve stimulation for urinary retention: results 18 months after implantation

PURPOSE: We investigate the efficacy of sacral neurostimulation in patients with idiopathic urinary retention in a prospective, randomized multicenter trial. MATERIALS AND METHODS: A total of 177 patients with urinary retention refractory to standard therapy were enrolled in the study. Greater than 50% improvement in baseline voiding symptoms during a 3 to 7-day percutaneous test stimulation qualified a patient for surgical implantation of an InterStim parallel system. Of the patients who qualified for implantation 37 were randomly assigned to a treatment and 31 to a control group. Patients in the treatment group underwent early surgical implantation of the sacral nerve stimulation system, while implantation was delayed in the control group for 6 months. Followup evaluations, including voiding diary analysis and temporary deactivation of the stimulator at 6 months, were conducted at 1, 3, 6, 12 and 18 months after implantation in the treatment group, and after 3 and 6 months in the control group. RESULTS: Compared to the control group, patients implanted with the InterStim system had statistically and clinically significant reductions in the catheter volume per catheterization (p <0.0001). Of the patients treated with implants 69% eliminated catheterization at 6 months and an additional 14% had a 50% or greater reduction in catheter volume per catheterization. Therefore, successful results were achieved in 83% of the implant group with retention compared to 9% of the control group at 6 months. Temporary inactivation of sacral nerve stimulation therapy resulted in a significant increase in residual volumes (p <0.0001) but effectiveness of sacral nerve stimulation was sustained through 18 months after implant. CONCLUSIONS: Results of this prospective, randomized clinical study demonstrate that sacral nerve stimulation is effective for restoring voiding in patients with retention who are refractory to other forms of treatment.     

Investigation of dysfunctional voiding in children with urgency frequency syndrome and urinary incontinence

PURPOSES: Dysfunctional voiding may result in lower urinary tract symptoms (LUTS) in children and is associated with urinary tract infection and vesicoureteral reflux (VUR). This study analyzed the videourodynamic investigations in children with urgency frequency syndrome and/or urinary incontinence. METHODS: Forty children, 1-13 years old, with urgency frequency syndrome and/or incontinence were investigated to determine their LUTS or for the assessment of VUR. Videourodynamic study was performed in all patients and the results were analyzed with clinical characteristics and underlying pathophysiology. RESULTS: Dysfunctional voiding was present in 75.7% of the children with detrusor overactivity, in 73.3% of the children with VUR, in 63% of the children with urinary incontinence, in 77% of the children with episodic urinary tract infection, and in all of the children with diurnal enuresis. Compared to children without dysfunctional voiding, the voiding pressure was significantly higher in children with dysfunctional voiding (with VUR, 61.1 +/- 29.8 vs. 24.8 +/- 15.8 cm H(2)O, p = 0.004; without VUR, 53.4 +/- 24.1 vs. 24.8 +/- 15.8 cm H(2)O, p = 0.010). Biofeedback pelvic floor muscle training and treatment with antimuscarinic agent effectively decreased detrusor pressure, increased bladder capacity and maximum flow rate, and reduced the grade of VUR in 5 children who had post-treatment urodynamic studies. CONCLUSIONS: This study has shown that dysfunctional voiding is highly prevalent in children with symptoms of urgency frequency and incontinence. Biofeedback pelvic floor muscle training is effective in treatment of dysfunctional voiding in children.     

Results of sacral neuromodulation therapy for urinary voiding dysfunction: outcomes of a prospective, worldwide clinical study

PURPOSE: This 5-year, prospective, multicenter trial evaluated the long-term safety and efficacy of sacral neuromodulation in patients with refractory urge incontinence, urgency frequency and retention. MATERIALS AND METHODS: A total of 17 centers worldwide enrolled 163 patients (87% female). Following test stimulation 11 patients declined implantation and 152 underwent implantation using InterStim. Of those treated with implantation 96 (63.2%) had urge incontinence, 25 (16.4%) had urgency frequency and 31 (20.4%) had retention. Voiding diaries were collected annually for 5 years. Clinical success was defined as 50% or greater improvement from baseline in primary voiding diary variable(s). RESULTS: Data for all implanted cases were reported. For patients with urge incontinence mean leaking episodes per day decreased from 9.6 +/- 6.0 to 3.9 +/- 4.0 at 5 years. For patients with urgency frequency mean voids per day decreased from 19.3 +/- 7.0 to 14.8 +/- 7.6, and mean volume voided per void increased from 92.3 +/- 52.8 to 165.2 +/- 147.7 ml. For patients with retention the mean volume per catheterization decreased from 379.9 +/- 183.8 to 109.2 +/- 184.3 ml, and the mean number of catheterizations decreased from 5.3 +/- 2.8 to 1.9 +/- 2.8. All changes were statistically significant (p <0.001). No life threatening or irreversible adverse events occurred. In 102 patients 279 device or therapy related adverse events were observed. At 5 years after implantation 68% of patients with urge incontinence, 56% with urgency frequency and 71% with retention had successful outcomes. CONCLUSIONS: This long-term study demonstrates that InterStim therapy is safe and effective for restoring voiding in appropriately selected cases refractory to other forms of treatment.     

Sacral neuromodulation for lower urinary tract dysfunction

Objectives

To review the technique, indications, results and working mechanisms of sacral neuromodulation (SNM) for lower urinary tract dysfunction.

Methods

The available literature on SNM for lower urinary tract dysfunction was searched. Based on the information available in the literature and also based on personal experience, the urological indications, technique, mechanisms of action and results of SNM are presented and discussed.

Results

SNM for lower urinary tract dysfunction involves stimulation of the 3rd sacral nerve with an electrode implanted in the sacral foramen and connected to a pulse generator. The technique is accepted by the FDA since 1997. Currently, SNM for lower urinary tract dysfunction has been successfully used in about 26,000 patients with various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. The actual procedure of SNM consists of a minimal invasive technique and is effective in about 70% of the patients who have been implanted with a permanent system. Also, in pelvic pain, interesting results have been described. SNM modulates the micturition reflexes at different levels in the central nervous system.

Conclusions

Sacral neuromodulation is a safe and effective therapy for various forms of lower urinary tract dysfunction, including urgency, frequency and urgency incontinence as well as non-obstructive urinary retention. It should be the first choice after failure of maximal conservative therapy.     

Sacral neuromodulation in the treatment of urgency-frequency symptoms: a multicenter study on efficacy and safety

PURPOSE: Neuromodulation of sacral nerves has shown promising results in correcting voiding dysfunction. We report the results of a multicenter trial designed to assess the efficacy of sacral nerve neuromodulation in patients presenting with refractory urinary urgency-frequency. MATERIALS AND METHODS: A total of 51 patients from 12 centers underwent baseline assessment, including a detailed voiding diary, urodynamic evaluation and percutaneous test stimulation of the sacral nerves at S3 and/or S4. All patients enrolled in the study had undergone prior conventional treatment, such as pharmacotherapy, hydrodistention and surgical intervention, which failed. All patients demonstrated a satisfactory response to trial stimulation and were randomly divided into a stimulation group (25 patients) and a control group (26). A sacral nerve stimulation device was implanted after 6 months in the control group. Patients were followed at 1, 3 and 6 months, and at 6-month intervals for up to 2 years after implantation of a neuroprosthetic InterStim* system. dagger The study variables included the number of voids daily, volume voided per void and degree of urgency before void. RESULTS: Compared to the control group, 6-month voiding diary results demonstrated statistically significant improvements (p <0.0001) in the stimulation group with respect to the number voids daily (16.9 +/- 9.7 to 9.3 +/- 5.1), volume per void (118 +/- 74 to 226 +/- 124 ml.) and degree of urgency (rank 2.2 +/- 0.6 to 1.6 +/- 0.9). Patients in the control group showed no significant changes in voiding parameters at 6 months. Significant improvements in favor of the stimulation group were noted in various parameters with respect to water cystometry and quality of life (SF-36). At 6 months after implant, neurostimulators were turned off in the stimulation group and urinary symptoms returned to baseline values. After reactivation of stimulation sustained efficacy was documented at 12 and 24 months. CONCLUSIONS: Neuromodulation of the sacral nerves is an effective, safe therapy that successfully treats significant symptoms of refractory urgency-frequency.     

Bilateral caudal epidural neuromodulation for refractory urinary retention: a salvage procedure

PURPOSE: Sacral neuromodulation with InterStim is approved for idiopathic urinary retention with a success rate of approximately 69%. To our knowledge currently no alternatives exist for patients in whom S3 neuromodulation fails. We report a new technique and our experience with bilateral caudal epidural neuromodulation in patients in urinary retention in whom unilateral or bilateral S3 InterStim failed. MATERIALS AND METHODS: Eight patients with multifactorial urinary retention in whom S3 InterStim previously failed underwent retrograde placement of bilateral tined leads into the caudal epidural space for sacral nerve stimulation. Patients with a 50% or greater clinical response underwent stage 2 Synergy-Versitrel implantable pulse generator placement. Patients were evaluated with voiding diaries, the Urinary Distress Inventory Questionnaire short form, quality of life assessment, need for catheterization and post-void residual urine preoperatively, and 6 months after implantation. RESULTS: Five of the 8 patients experienced return of micturition and underwent placement of a permanent implantable pulse generator. At 6-month followup 4 of the 5 patients voided to completion. One patient improved more than 50% and now catheterizes once daily with a post-void residual urine of 200 cc. There was a significant decrease in obstructive symptoms on the Urinary Distress Inventory Questionnaire short form and improved overall quality of life. CONCLUSIONS: To our knowledge this is the first report of the use of bilateral caudal epidural neuromodulation for refractory urinary retention. This therapy can be successful in patients in whom prior InterStim therapy failed.     

Sacral neuromodulation after stabilization of L2-S1 vertebrae with metallic fixation devices: is it feasible?

Sacral neuromodulation is a surgical treatment for voiding difficulties. We report the case of a patient affected by overflow urinary incontinence and reduced bladder sensation subsequent to decompression and stabilization of L2-S1, showing that sacral nerve stimulation can be used in patients with sacral anatomy distortion and metallic fixation system. In these cases, implant is feasible with fluoroscopic guidance and little changes of standard implantation procedure.     

Sacral nerve stimulation for treatment of refractory urinary urge incontinence. Sacral Nerve Stimulation Study Group.

PURPOSE: A prospective, randomized study was performed to evaluate sacral nerve stimulation for the treatment of refractory urinary urge incontinence. MATERIALS AND METHODS: Primary outcome variables were obtained from voiding diaries. After baseline evaluation candidates who satisfied inclusion criteria were enrolled into the study. Test stimulation results determined eligibility for randomization into a stimulation (treatment) or delay (control) group. The stimulation group included 34 patients who underwent implantation and were followed for 6 months. The delay group comprised 42 patients who received standard medical therapy for 6 months and then were offered implantation. The stimulation group completed a therapy evaluation test (on versus off) after 6 months. RESULTS: At 6 months the number of daily incontinence episodes, severity of episodes and absorbent pads or diapers replaced daily due to incontinence were significantly reduced in the stimulation compared to the delay group (all p<0.0001). Of the 34 stimulation group patients 16 (47%) were completely dry and an additional 10 (29%) demonstrated a greater than 50% reduction in incontinence episodes 6 months after implantation. Efficacy appeared to be sustained for 18 months. During the therapy evaluation test the group returned to baseline levels of incontinence when stimulation was inactivated. Urodynamic testing confirmed that sacral nerve stimulation did not adversely affect voiding function. Complications included implantable pulse generator site pain in 15.9% of the patients, implant site pain in 19.1% and lead migration in 7.0%. Surgical revision was required in 32.5% of patients with implants to resolve a complication. There were no reports of permanent injury or nerve damage. CONCLUSIONS: Sacral nerve stimulation is safe and effective in treating refractory urinary urge incontinence.     

Sacral nerve neuromodulation in the treatment of patients with refractory motor urge incontinence: long-term results of a prospective longitudinal study

PURPOSE: Conservative treatment rarely results in a durable cure of patients with urge incontinence and bladder overactivity. Instrumental and surgical procedures often have significant side effects and less than optimal results. We developed a technique of sacral nerve neuromodulation using chronic unilateral electrical stimulation of the S3 sacral nerve to inhibit the micturition reflex to provide effective nondestructive alternative therapy for patients whose condition is refractory to conservative treatment. MATERIALS AND METHODS: Of 85 patients 45 who responded to a test with a temporary electrode underwent implantation of a permanent S3 sacral nerve electrode coupled to a pulse generator. Treatment results were evaluated by urodynamic studies and voiding/incontinence diaries documenting pad use, incontinence episodes, voiding frequency and voided volume. Partial success and cure were defined as 50% to 90% and more than 90% improvement, respectively, in pad use and/or incontinence episodes. RESULTS: Of 45 patients 18 (40%) were cured at an average followup of 47.1 months and 9 (20%) achieved partial success. Median number of pads used and median number of incontinence episodes daily had decreased from 5.4 to 1.2 (p = 0.0001) and 7.1 to 1.3 (p = 0.0001), respectively, 6 months after implantation. Subsequently these results remained almost constant for 5 years. Bladder overactivity disappeared in 19 of the 44 patients (43%). The repeat intervention rate was 37.7% and there was no permanent injury or nerve damage. CONCLUSIONS: Sacral nerve neuromodulation is safe, effective and durable in patients with urge incontinence refractory to conservative treatment.     

The role of neuromodulation in the management of urinary urge incontinence

OBJECTIVE: To examine the benefit-risk profile of neuromodulation in treating refractory urinary urge incontinence and other voiding disorders. PATIENTS AND METHODS: The outcome measures from all patients in pivotal clinical trials who had undergone sacral nerve stimulation were analysed retrospectively. RESULTS: Neuromodulation was effective in several clinical studies; the response is durable and the benefit-risk profile good. CONCLUSION: Sacral nerve stimulation is becoming the standard of care for refractory overactive bladder and retention problems. The potential benefit of neuromodulation should be included in female urology and gynaecology training programmes.     

Sacral neuromodulation in functional urinary retention: an effective way to restore voiding

OBJECTIVE: To determine the long-term efficacy and complications of sacral nerve stimulation as an alternative therapy for functional unobstructive urinary retention, often considered to be psychogenic and effectively treated by clean intermittent catheterization, but for which pelvic floor dysfunction has been recognized as a possible cause. PATIENTS AND METHODS: Twenty patients (17 women and three men, mean age 48 years) with idiopathic, unobstructive functional urinary retention and in whom other forms of therapy had failed, had a pulse generator implanted (Medtronic, Minneapolis, MN, USA) and a sacral nerve implant. Their mean duration of symptoms was 68 months; 13 patients had chronic pelvic and perineal pain associated with their obstructive voiding symptoms. All patients were managed with clean intermittent catheterization and pharmacological therapy (alpha-blockers) before the procedure. All patients had a percutaneous nerve evaluation before the permanent implant, which showed> 50% improvement in their symptoms. All patients were evaluated at 1, 6 12, 18 and 24 months, then yearly thereafter. The results were assessed both subjectively by patient's symptoms and objectively by checking the postvoid residual volume (PVR) and voided volume. RESULTS: Eighteen patients were able to void spontaneously with a mean increase in voided volume from 48 to 198 mL, and a significant decrease in PVR from 315 to 60 mL. Eighteen of the patients had a > or = 50% improvement in their symptoms and said they would recommend the therapy to a friend or relative. Complications occurred in six patients. CONCLUSION: Sacral nerve stimulation is an effective and durable new approach to functional urinary retention, with few associated complications. Test stimulation provides a valuable tool for selecting patients.