Percutaneous Nerve Evaluation Research Articles

Contrasting the Percutaneous Nerve Evaluation Versus Staged Implantation in Sacral Neuromodulation

Sacral neuromodulation is increasingly used for the treatment of voiding dysfunction, pelvic pain syndromes, and gastrointestinal disorders. While increased use of this technology has led to a greater understanding of its potential as well as its limitations, difficulty persists in identifying the patients that will benefit most. Either of two trial stimulation techniques is performed before placement of a permanent neuromodulator: the monopolar percutaneous nerve evaluation and the tined quadripolar staged trial. The preponderance of recent literature asserts the superior sensitivity of the staged trial over percutaneous nerve evaluation. However, the techniques offer disparate advantages, and other issues, such as cost-effectiveness, remain largely unexplored. The role of sacral neuromodulation will continue to expand as physicians and patients become increasingly aware of its therapeutic potential. Widespread adoption of this clinically superior technique will most rapidly help the greatest number of patients.

Predictors of the outcome of percutaneous nerve evaluation for faecal incontinence

The aim was to identify patient-related and operative factors that might predict the outcome of percutaneous nerve evaluation (PNE). Demographic data (age, sex, body mass index), primary cause of incontinence, number and type of incontinence episodes, results of endoanal ultrasonography and manometry, and operative factors from 244 patients who underwent PNE for faecal incontinence were reviewed. Each factor was assessed according to the outcome, and explored by univariable and multivariable analysis to identify predictors. Some 191 patients (78.3 per cent) had a successful PNE. A low amplitude of sensory threshold during PNE (odds ratio (OR) 0.69 (95 per cent confidence interval 0.59 to 0.81); P < 0.001) and lead placement anterior to the sacral cortex (OR 9.06 (4.70 to 17.45); P < 0.001) were positive predictive factors for successful outcome of PNE. Neither a defect nor an abnormality of either the external (OR 0.88 (0.39 to 1.97); P = 0.749) or internal (OR 0.62 (0.27 to 1.42); P = 0.255) anal sphincter was a negative predictive factor. Demographic variables, number of incontinence episodes and the motor response threshold did not predict outcome. No preoperative predictor of PNE outcome could be identified. Predictors were limited to operative lead placement and sensory response during PNE.

Six Years of Experience With Sacral Nerve Stimulation for Fecal Incontinence

Sacral nerve stimulation is one of many new surgical modalities for fecal incontinence. Short-term results from sacral nerve stimulation have been more encouraging than those from other modalities. The aim of this study was to report the outcome of percutaneous nerve evaluation tests and sacral nerve stimulation for the treatment of fecal incontinence from a single center covering a period of 6 years since the procedure was introduced. All of the candidates for a percutaneous nerve evaluation test and sacral nerve stimulation seen at our anal physiology unit between March 2001 and March 2007 were included in the study. A total of 177 patients with fecal incontinence (160 females), median age 59.5 (range, 27-88) years, underwent a percutaneous nerve evaluation test. Of these patients, 142 (80%) had a positive test, including 21 of 25 (84%) patients who required a repeat percutaneous nerve evaluation test. Because of a functional failure, 16 patients underwent a revision of the permanent electrode, 7 of whom (44%) were satisfied with the functional result after the revision. Of 126 patients, 15 (12%) have undergone an explantation, with an infection rate of only 1.6%. Overall, after a median follow-up of 24 (range, 3-72) months, the median Wexner incontinence score decreased from 16 (range, 6-20) to 10 (range, 0-20) (P < .0001). In the 10 patients who underwent at least 6 years of treatment, the effect was sustained, as the median Wexner incontinence score decreased from 20 (range, 12-20) to 7 (range, 2-11) (P < .0001). Sacral nerve stimulation is a simple, safe, and minimally invasive technique with low morbidity and excellent results, which appear to be maintained for the first 6 years after the procedure. For patients who underwent the treatment, median Wexner incontinence score decreased significantly after a median follow-up of 24 (range, 3-72) months. Twelve percent were explanted. The infection rate was 1.6%.

Sacral neuromodulation: Therapy evolution

Objectives:Sacral neuromodulation has gained increased worldwide acceptance as the standard of care in patients with refractory overactive bladder (OAB) and non-obstructive urinary retention (NOUR). This review will detail the evolution of the technology.Materials and Methods:The mechanism of action and advances in treatment, including tined lead, fluoroscopic imaging, and smaller implantable pulse generator (IPG) are reviewed. This discussion also explores expanding indications and future advances including interstitial cystitis, chronic pelvic pain, neurogenic bladder, fecal incontinence, constipation, and dysfunctional elimination syndrome in children.Results:Sacral neuromodulation (SNM) exerts its influence by modulation of sacral afferent inflow on storage and emptying reflexes. The tined lead allows for placement and stimulation to be performed in the outpatient setting under local anesthesia with mild sedation. Lead migration has been minimal and efficacy improved. The use of fluoroscopy has improved accuracy of lead placement and has led to renewed interest in bilateral percutaneous nerve evaluation (PNE). Bilateral PNE can be performed in the office setting under local anesthesia, making a trial of therapy less expensive and more attractive to patients. A smaller IPG has not only improved cosmesis, but decreased local discomfort and need for revision. The role for SNM continues to expand as clinical research identifies other applications for this therapy.Conclusions:Our understanding of SNM, as well as technological advances in therapy delivery, expands the pool of patients for which this form of therapy may prove beneficial. Less invasive instrumentation may even make this form of therapy appealing to patients without refractory symptoms.

Long-Term Outcomes of Urgency-Frequency Syndrome Due to Painful Bladder Syndrome Treated With Sacral Neuromodulation and Analysis of Failures

We present our long-term experience with sacral neuromodulation devices placed in patients with painful bladder syndrome to determine whether the benefit decreases over time. Between January 2000 and July 2004, 32 women and 7 men with interstitial cystitis/painful bladder syndrome in whom previous conventional therapy failed underwent sacral neuromodulation test stimulation. Before 2003 a percutaneous test lead was placed in the clinic setting. After 2003 a quadripolar permanent lead was placed in the operating room. Permanent generators were implanted if the patient had more than 50% relief from the presenting complaint, which was defined as urinary or pelvic pain, urgency, or urinary frequency. Long-term outcomes included battery depletion, device malfunction, infection or loss of benefit as well as any change in need for medications. Of 39 patients 22 went from test stimulation to permanent generator implantation. There were significant differences in short-term but not long-term outcomes between the 2 methods of test stimulation. Of 33 patients undergoing percutaneous nerve evaluation 13 (39.4%) met the criteria for permanent generator implantation, while 9 of 11 (81.8%) evaluated with the quadripolar lead met these criteria (p = 0.015). Long-term success between the groups was similar at 92.3% (12 of 13) vs 77.8% (7 of 9) (p = 0.329) during an average followup of 59.9 months. Eleven (50.0%) devices required explantation. Of 22 patients 3 (13.6%) lost benefit over time. These patients appear to respond best to permanent quadripolar lead placement but long-term results do not appear to be independently affected by the method of test stimulation. Loss of benefit over time is not common.

Factors Associated with Percutaneous Nerve Evaluation and Permanent Sacral Nerve Modulation Outcome in Patients with Fecal Incontinence

Sacral nerve modulation is an established treatment for fecal incontinence. Little is known about predictive factors for successful percutaneous nerve evaluation (or test stimulation) and permanent sacral nerve modulation outcome. The purpose of this retrospective study was to discover predictive factors associated with temporary and permanent stimulation. We analyzed data from test stimulations performed in patients with fecal incontinence from March 2000 until May 2007. Successful outcome was defined as >50% improvement of incontinence episodes in three weeks. Patients with a successful test stimulation were eligible for permanent sacral nerve modulation implantation. All patients who subsequently had permanent sacral nerve modulation were analyzed. Logistic regression was used to determine the predictive power of baseline demographics and diagnostic variables. Test stimulations were performed in 245 patients (226 females; mean age, 56.6 (standard deviation, 12.8) years). Our analysis showed that older age (P = 0.014), external anal sphincter defects (P = 0.005), and repeated procedures after initial failure (P = 0.001) were significantly related to failure. One hundred seventy-three patients (70.6%) were eligible for permanent sacral nerve modulation implantation. The analysis showed no significant predictive factors related to permanent sacral nerve modulation. Three predictive factors were negatively associated with the outcome of test stimulation: older age, repeated procedures, and a defect in the external anal sphincter. These factors may indicate lower chances of success for test stimulation but do not exclude patients from sacral nerve modulation treatment. Although assessed in a selected patient group, no factors were predictive of the outcome of permanent stimulation.

Sacral Neuromodulation for the Treatment of Chronic Functional Anorectal Pain: A Single Center Experience

Treatment of functional anorectal pain disorders remains a challenge. The purpose of this study is to describe a single center experience with sacral neuromodulation for the treatment of chronic functional anorectal pain. This is a retrospective study based on prospectively collected data of patients treated with sacral neuromodulation for functional anorectal pain from April 2005 to August 2008. Symptoms were analyzed using a visual analog scale pain score (0 to 10). A 7-point Likert scale was used to rate global perceived effect. All patients had a percutaneous nerve evaluation and subsequent test stimulation to assess sacral neuromodulation outcome prior to permanent implantation. Patients were eligible for permanent sacral neuromodulation in case of a pain score <3 during test stimulation and/or >50% decrease in the pain score compared to baseline. Nine patients (2 males) were included in this study. Mean age was 53.8 years (27.6 to 74.0). Four patients (1 male) had successful test stimulation and were eligible for permanent implantation. Median pain score decreased from 8.0 (6.0 to 9.0) to 1.0 (0 to 2.0). All patients experienced a lasting improvement during the follow-up till 24 months. Global perceived effect in successful patient was 1 (completely recovered) in one patient and 2 (much improved) in three patients. This study showed that sacral neuromodulation can be a successful treatment for functional anorectal pain not responding to other treatments. Improvement obtained during test stimulation is a good predictor (diagnostic) for sustained success of permanent sacral neuromodulation.

Can Sensory and/or Motor Reactions During Percutaneous Nerve Evaluation Predict Outcome of Sacral Nerve Modulation?

A major advantage of sacral nerve modulation in the treatment of fecal incontinence is the ability to determine the likely treatment outcome before implantation by means of a percutaneous nerve evaluation and a test stimulation period. This study evaluated the predictive value of both sensory and motor responses during percutaneous nerve evaluation for determining the outcome of subchronic test stimulation and permanent stimulation. All percutaneous nerve evaluation procedures performed between 2000 and 2007 were analyzed. Two hundred eight procedures (194 females; mean age, 56.7 years) were included in this study. Correct needle placement was confirmed by typical S-3 sensory and/or motor responses. The sensory and motor responses during the procedure were analyzed in relation to the outcomes of the test stimulation and permanent stimulation. In all, 72.6% of patients had a successful subchronic test stimulation. A total of 13.9% had no motor response. There was no significant difference in outcome between the group with only sensory responses and the group with both sensory and motor responses (P = 0.89; odds ratio, 1.01; 95% confidence interval, 0.42-2.43). Correlation with permanent implantation showed no significant difference between both groups in outcome (P = 0.53; odds ratio, 0.48; 95% confidence interval, 0.17-1.41). Positive motor responses during percutaneous nerve evaluation are highly predictive of a successful outcome of subchronic test stimulation and permanent sacral nerve modulation. Sensory responses also have the same predictive value. For this reason, percutaneous nerve evaluation preferably should be performed in awake patients under local anesthesia to avoid missing those who may benefit from permanent stimulation but who do not have a motor response during the procedure.

Detrusor Acontractility in Urinary Retention: Detrusor Contractility Test as Exclusion Criteria for Sacral Neurostimulation

Results of sacral neurostimulation in urinary retention are reported in the literature without distinction between the 2 functional disorders causing this condition, detrusor acontractility and functional outlet obstruction. We have suggested a stimulation test to differentiate irreversible bladder myopathy (or complete neurogenic lesion) from potential bladder contractility eligible for sacral neurostimulation. Direct electrostimulation of the sacral nerves was performed with the patient under general anesthesia. Urodynamic monitoring of bladder (detrusor contractility test) and bowel pressures were used. If no bladder contraction (negative detrusor contractility test) was recorded with positive somatic and bowel responses a irreversible bladder myopathy was supposed and the patient discharged home. If no bladder and no bowel contraction were recorded a complete neurogenic lesion was supposed and the patient was also discharged. Of 96 patients tested with the detrusor contractility test 72 (65%) had no bladder contraction and were excluded from sacral neurostimulation therapy. In this series 15 patients had already been tested with percutaneous nerve evaluation on each S3 nerve with negative results. In 18 cases no bladder and no bowel contraction was evoked (neurogenic lesion). In the remaining 54 cases (bowel but no bladder contraction) a bladder myopathy was supposed. In 24 patients the detrusor contractility test was positive and 12 of these underwent implantation with a permanent device for sacral neurostimulation. The detrusor contractility test can be considered a reliable tool to rule out detrusor acontractility due to irreversible bladder myopathy or complete neurogenic lesion from sacral neurostimulation.

Temporary Sacral Nerve Stimulation for Treatment of Irritable Bowel Syndrome: A Pilot Study

This study was designed to evaluate the effect of temporary sacral nerve stimulation in patients with diarrhea-predominant irritable bowel syndrome. Symptoms of diarrhea-predominant irritable bowel syndrome and disease-specific quality of life was evaluated in six patients before and during percutaneous sacral nerve evaluation test. Primary end points were differences between total irritable bowel syndrome symptom score and total quality of life score before and during stimulation. Secondary end points were differences between the variable domains. Percutaneous sacral nerve evaluation test was performed in five women and one man (median age, 33 (range, 26-54) years). The irritable bowel syndrome symptom score decreased from 48.9 to 28.3 (P = 0.004). Pain, bloating, and diarrhea were significantly reduced from 7.9, 13.5, and 17.3 to 4.4, 7.2, and 10.6, respectively (P = 0.02, P = 0.01, P = 0.03). The irritable bowel syndrome quality of life score decreased from 99.3 to 59.6 (P = 0.009). Daily activities, emotional distress, eating habits, and fatigue were significantly reduced from 26.9, 22.2, 15.2, and 23.2 to 16.9, 13.3, 8, and 14.4, respectively (P = 0.02, P = 0.02, P = 0.02, P = 0.007). Two weeks after cessation of stimulation, the patients had symptoms as before stimulation. Temporary sacral nerve stimulation provides a significant reduction in diarrhea-predominant irritable bowel symptoms and improves quality of life. Further studies with permanent implantation and double-blind crossover ON-and-OFF-stimulation to evaluate the impact of placebo effect are needed.

Sacral nerve stimulation for faecal incontinence alters colorectal transport

Sacral nerve stimulation reduces the frequency of defaecation in patients with faecal incontinence. The aim of this study was to examine the mechanism behind the reduced number of bowel movements in incontinent patients treated with sacral nerve stimulation. The study included 20 patients with faecal incontinence and a positive percutaneous nerve evaluation test: 19 women and one man, with a median age of 63 (range 28-78) years. Colorectal scintigraphy was performed to assess colorectal emptying at defaecation before and after implantation. Segmental colorectal transit times were determined using radio-opaque markers. The median frequency of defaecation per 3 weeks decreased from 56 (range 19-136) to 26 (range 12-78) (P < 0.002). At defaecation, antegrade transport from the ascending colon decreased from a median score of 8 (range 0-23) to 0 (range 0-11) per cent (P = 0.001), while retrograde transport from the descending colon increased from a median score of 0 (range 0-14) to 2 (range 0-30) per cent (P = 0.039). The median defaecation score was unchanged. There was a non-significant increase in median total gastrointestinal transit time from 2.5 (range 0.9-6.2) to 3.3 (range 0.8-6.2) days (P = 0.079). Sacral nerve stimulation reduces antegrade transport from the ascending colon and increases retrograde transport from the descending colon at defaecation. This may prolong colonic transit time and increase the storage capacity of the colon.

Indikationen und Ergebnisse der Sakralnervenstimulation bei Stuhlinkontinenz

Sacral nerve stimulation (SNS) is an effective and less invasive treatment of faecal incontinence (FI). Patient selection has evolved from strict criteria to a more liberal approach, since temporary testing reliably predicts the efficacy of permanent stimulation in FI of various aetiologies. From November 2005 until June 2007, we evaluated 20 consecutive patients (17 females, 3 males) with FI by percutaneous nerve evaluation (PNE), i. e., temporary stimulation. 13 patients proceeded to a permanent implantation of a pulse generator (3 bilateral generators). 11 patients with permanent stimulation were eligible for a minimum follow-up of 3 months. Median follow-up for this group was 10 (range 3-19) months. All patients provided bowel diaries, the disease-specific quality of life questionnaire of the American Society of Colon and Rectal Surgeons (ASCRS), and the Standard Short Form Health Survey Questionnaire (SF-36) at baseline, screening and at the follow-up. The aetiologies of the FI were pelvic floor insufficiency (n = 12), history of anterior resection (n = 3), history of surgery for disk prolaps (n = 2), sphincter disruption (n = 1), history of surgery for recto-vaginal fistula (n = 1), and idiopathic (n = 1). The mean number of incontinence episodes dropped from 9.9 to 1.3 during temporary testing (p = 0.02) and to 4.5 at last follow-up (p = 0.043). The quality of life assessment showed a significant improvement in the subscale embarrassment of the ASCRS (p = 0.043). There were 2 minor postoperative complications, and 1 medium-term failure of SNS treatment. SNS is a minimally invasive and effective treatment of FI. A pragmatic approach is justified due to the possibility of temporary testing and the low rate of complications.

Sacral nerve stimulation as an option for the treatment of faecal incontinence in patients suffering from cauda equina syndrome

Retrospective clinical study with 1-year follow-up. Treatment of faecal incontinence by permanent sacral nerve stimulation (SNS) in patients suffering from cauda equina syndrome (CES). Klosterneuburg, Austria. A flaccid paresis of the sphincter ani muscle and the pelvic floor combined with faecal incontinence can occur in patients suffering from CES as a result of a trauma in the region of the lumbar spine. If the incontinence cannot be managed by the use of laxatives or anal tampons, the patient is restricted in his/her quality of life. Thus, it was our aim to improve sphincter function and anal sensitivity to achieve voluntary rectal defaecation. The functional integrity of at least one sacral root (S2-S4) was determined through percutaneous nerve evaluation (PNE). Following this analysis, a period of external temporary SNS was performed to evaluate the functional effect. If there was a decrease in the number of episodes of faecal incontinence during this evaluation period, a neurostimulation device (InterStim; Medtronic) was implanted. A total of 11 patients suffering from flaccid paresis of the anal sphincter muscle and faecal incontinence caused by CES underwent PNE, which was successful in 8 patients. Two of these patients were eliminated from the procedure at the end of the temporary SNS period, one patient refused the permanent implantation. Therefore, five patients proceeded to permanent implantation, which led to an improved continence in all the cases. In the synopsis of the preoperative proctologic and neurological findings, successful electric stimulation of the sacral roots can be expected in incomplete CES. In the case of flaccid paresis of the anal sphincter muscles caused by an incomplete CES, permanent SNS offers a promising option for the treatment of faecal incontinence. .

Urodynamic evaluation of sacral neuromodulation for urge urinary incontinence

To evaluate the urodynamic data before and 6 months after implantation of sacral neuromodulation (SNM, an established treatment for voiding dysfunction, including refractory urge urinary incontinence, UI) and to assess the correlation between the urodynamic data and clinical efficacy in patients with UI. In all, 111 patients with a >50% reduction in UI symptoms during a percutaneous nerve evaluation test qualified for surgical implantation of SNM. Patients were categorized in two subgroups, i.e. those with UI with or without confirmed detrusor overactivity (DO) at baseline. At the 6-month follow-up all patients had a second urodynamic investigation, with the stimulator switched on. At baseline, there was urodynamically confirmed DO in 67 patients, while 44 showed no DO. A review of filling cystometry variables showed a statistically significant improvement in bladder volumes at first sensation of filling (FSF) and at maximum fill volume (MFV) before voiding for both UI subgroups, compared with baseline. In 51% of the patients with UI and DO at baseline, the DO resolved during the follow-up. However, those patients were no more clinically successful than those who still had DO (P = 0.73). At the 6-month follow-up, 55 of 84 implanted patients showed clinical benefit, having a >or=50% improvement in primary voiding diary variables. Patients with UI but no DO had a higher rate of clinical success (73%) than patients with UI and DO (61%), but the difference was not statistically significant. These urodynamic results show a statistically significant improvement in FSF and MFV in patients with UI with or with no DO after SNM. Although there was a urodynamic and clinical improvement in both groups, patients with UI but no DO are at least as successful as patients with UI and DO. Therefore in patients with UI, DO should not be a prerequisite selection criterion for using SNM.

Is a morphologically intact anal sphincter necessary for success with sacral nerve modulation in patients with faecal incontinence?

Sacral nerve modulation (SNM) for the treatment of faecal incontinence was originally performed in patients with an intact anal sphincter or after repair of a sphincter defect. There is evidence that SNM can be performed in patients with faecal incontinence and an anal sphincter defect. Two groups of patients were analysed retrospectively to determine whether SNM is as effective in patients with faecal incontinence associated with an anal sphincter defect as in those with a morphologically intact anal sphincter following anal repair (AR). Patients in group A had had an AR resulting in an intact anal sphincter ring. Group B included patients with a sphincter defect which was not primarily repaired. Both groups underwent SNM. All patients had undergone a test stimulation percutaneous nerve evaluation (PNE) followed by a subchronic test over 3 weeks. If the PNE was successful, a permanent SNM electrode was implanted. Follow-up visits for the successfully permanent implanted patients were scheduled at 1, 3, 6 and 12 months and annually thereafter. Group A consisted of 20 (19 women) patients. Eighteen (90%) had a positive subchronic test stimulation. Twelve patients had a successful SNM implant during middle-term follow-up. Group B consisted of 20 women. The size of the defect in the anal sphincter varied between 17% and 33% of the anal circumference. Fourteen (70%) had a positive subchronic test stimulation. Twelve patients had a successful SNM implant during middle-term follow-up. In both groups, the mean number of incontinence episodes decreased significantly with SNM (test vs baseline: P = 0.0001, P = 0.0002). There was no significant difference in resting and squeeze pressures during SNM in group A, but in group B squeeze pressure had increased significantly at 24 months. Comparison of patient characteristics and outcome between groups A and B revealed no statistical differences. A morphologically intact anal sphincter is not a prerequisite for success in the treatment of faecal incontinence with SNM. An anal sphincter defect of <33% of the circumference can be effectively treated primarily with SNM without repair.

Subcutaneous tunneling of the temporary testing electrode significantly improves the success rate of subchronic sacral nerve modulation (SNM)

Sacral nerve modulation (SNM) is an effective way to treat non-neurogenic dysfunctions of pelvic organs. For over 20 years, this technique has been used for the treatment of overactive bladder, urinary retention, pelvic pain and even more recently, fecal incontinence and constipation. The objective of the study is to improve the fixation of the temporary testing electrode (TTE) in order to obtain more reliable results in the testing phase which should lead to have a comparable success rate as the two-stage implant for a chronic implant. Twenty-eight patients (ratio of sex women:men = 3:1; with overactive bladder, urinary retention, pelvic pain syndrome and fecal incontinence) were evaluated by the modified temporary test electrode (TTE) placement. With the subcutaneous tunneling technique (mean time of evaluation 8.3 days), it is possible to perform percutaneous nerve evaluation (PNE) more effectively with an objective, reliable and less expensive outcome prior to the implantation of the implantable sacral nerve stimulator in almost 80% of the evaluated patients. Because the costs of therapy are not covered by health insurance in all countries, there is a need for an effective and inexpensive way to test and select patients appropriately. The tunneled TTE maintains its place for consistent amplitude during the entire test duration. The modification of placing the TTE produces repayable results. This technique can be performed on an outpatient basis to evaluate sacral nerve modulation as an early treatment option for non-dysfunctions of pelvic organs before they are forwarded to a specialized center for a chronic SNM implantation.

Five-Year Follow-up After Sacral Neuromodulation: Single Center Experience

Objective. We studied long-term clinical efficacy of sacral neuromodulation (SNM) therapy in patients with refractory urgency incontinence (UI), urgency/frequency (UF) and voiding difficulty (VD), together with urodynamic data at baseline and sixmonths postimplant. Materials and Methods. Twenty-two patients were implanted with a neurostimulator after a positive response to a percutaneous nerve evaluation test defined as a greater than 50% improvement in symptoms. Results. At five-year follow-up, the number of incontinent episodes and pad usage per day decreased significantly in 10 out of 15 UI patients. Two of five UF patients were successfully treated with SNM; the number of daily voids for all UF patients decreased from 25 to 19 and average voided volume increased from 98 to 212mL. One of the two VD patients was able to void to completion. Mean first sensation of filling at the six-month urodynamic investigation for the UI and UF patients increased from 78 to 241mL and 141 to 232mL, respectively, and the maximum bladder capacity increased from 292 to 352mL and 223 to 318mL, respectively. Five of 22 patients underwent device explant and one patient still has an inactive stimulator implanted. Conclusion. SNM is an effective treatment modality that offers sustained clinical benefit in the majority of patients with refractory UI, UF, and VD that do not respond to other, more conservative therapies.

Urethral Instability and Sacral Nerve Stimulation—A Better Parameter to Predict Efficacy?

Urodynamic parameters that predict the outcome of sacral nerve stimulation are difficult to define. We studied the predictive value of urethral instability and other urodynamic parameters on the efficacy of sacral nerve stimulation. Patients with refractory voiding disorders were implanted with a neurostimulator after responding with more than 50% improvement in main symptoms after percutaneous nerve evaluation. Filling cystometry was performed with 3 urethral sensors and 1 bladder sensor at baseline and 6 months after implantation. Urethral pressure variations more than 15 cm H(2)O were considered pathological and defined as urethral instability. Clinical efficacy was evaluated by voiding diary data and defined as successful when greater than 50% improvement was observed. A total of 19 female patients enrolled in the study. At baseline detrusor overactivity was observed in 9 patients, while 18 showed urethral instability. Sacral nerve stimulation therapy was successful in 13 patients (68%). The number of pads used per day and the severity of leakage decreased significantly. Of the 13 successfully treated patients 12 showed urethral instability at baseline. Detrusor overactivity was present in 4 successfully treated patients. Urethral instability disappeared in 7 of the 13 successfully treated patients and detrusor overactivity disappeared in only 1 of these patients. In this study urethral instability appeared to be a valuable urodynamic parameter for predicting the outcome of sacral nerve stimulation.

Quality of Life and Morbidity After Permanent Sacral Nerve Stimulation for Fecal Incontinence

Permanent sacral nerve stimulation (SNS) is a promising emerging treatment for fecal incontinence. However, there is little data on morbidity and quality of life (QOL) during long-term stimulation. Prospective trial to assess morbidity and QOL in patients treated with SNS. Median follow-up was 13 months (range, 1-42 months). University hospital providing primary, secondary, and tertiary care. Between December 2001 and July 2005, SNS was tested in 44 patients (30 women), with a median age of 65 years (range, 15-88 years). Percutaneous nerve evaluation and permanent insertion of an implantable pulse generator. Morbidity, stool diary, and Wexner Score for fecal incontinence; Hanley Score for urinary incontinence; and Gastrointestinal Quality of Life Index, the 36-item short form health survey, and the Royal London Hospital questionnaire for QOL. A permanent stimulator was implanted in 37 patients (84%). Eight patients (22%) experienced complications that required surgical intervention. (A successful restimulation was possible for 5 of those patients.) Adverse effects of SNS were remedied in 5 patients by reprogramming the stimulator. Wexner Scores decreased from a median of 16 points preoperatively (range, 6-20), to a median of 5 points postoperatively (range, 0-13; P<.001). The median number of involuntary stool losses and for urge defecations also decreased significantly. Significant improvement in QOL was found in both generic and incontinence-specific questionnaires (P<.05). The success rate of SNS was 77% (34 of 44 patients) and 92% (34 of 37) in patients with permanent implantation. The minimally invasive technique of SNS is safe and effective. Most adverse effects can be easily remedied. Our data demonstrate that SNS significantly improves patients' QOL, including their physical and psychological well-being.

Medium‐term experience of sacral neuromodulation by tined lead implantation

To describe patient selection for sacral neuromodulation, also known as Interstim therapy, and the results of tined-lead implantation in the medium term. In all, 49 patients, 39 with refractory overactive bladder symptoms and 10 with urinary retention, were implanted with the tined lead under local anaesthesia. The mean (sd) test period was 12.4 (5.8) days. Patients were implanted when they had a > or = 50% improvement in voiding diary variables during the test period. The mean follow-up for implanted patients was 15.5 (7.9) months. Changes in voiding variables were compared using a t-test. Ten patients had a one-stage and 39 a two-stage implant; of the latter group, 31 (80%) had a positive response and eight (21%) did not. In all, 31 patients were included in the follow-up. At the last follow-up, 28 (90%) patients had a >50% improvement in diary variables and three (10%) did not. In 21 patients with urgency symptoms the mean (sd) number of voids decreased from 11.7 (8.9)/day at baseline to 7.3 (3.4)/day (P = 0.1); the voided volume increased from 160.2 (70.7) mL to 231.1 (119.5) mL (P = 0.001); and the number of leakages decreased from 9.5 (8.7) to 3.3 (2.2)/day (P = 0.17). In the 10 patients with retention, the number of catheterizations decreased from 5.44 (1.6)/day with a volume of 297.6 (76.8) mL, to 1.2 (1.7)/day and 111.6 (158.1) mL; the mean number of voids increased from 3.7 (3.8)/day with a volume of 123.3 (141.7) mL, to 4.2 (2.4)/day and 248.3 (146.0)mL. There were no significant differences in the variables in the patients with retention. Seven patients had an adverse event. There was one incomplete electrode migration that was treated conservatively. This new minimally invasive approach gives positive results in the medium term. Two-stage testing with the tined lead seems more reliable than the classic percutaneous nerve evaluation. The lead anchoring method seems sufficient for fixing the electrode in the medium term.