Results of Sacral Neuromodulation Therapy for Urinary Voiding Dysfunction: Outcomes of a Prospective, Worldwide Clinical Study

Article Outline

• Abstract
• Materials and Methods
  • Patient Selection and Evaluation
  • Patient Disposition
  • Statistical Analysis
• Results
  • Efficacy for Urge Incontinence
  • Efficacy for Urgency Frequency
  • Efficacy for Urinary Retention
  • Safety
• Discussion
• Conclusions
• References
• Copyright

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.

Key Words: electric stimulation therapy, urination disorders, urinary bladder

Abbreviations and Acronyms: AE, adverse event, FDA, Food and Drug Administration, INS, implantable neurostimulator, PAS, post approval study, PNE, percutaneous nerve evaluation, SNM, sacral neuromodulation, UF, urgency frequency, UI, urge incontinence

During the last decade sacral neuromodulation, often referred to as sacral nerve stimulation or InterStim therapy, has proven to be an effective treatment modality for voiding dysfunctions that are refractory to conservative treatment, particularly UI, UF and idiopathic nonobstructive retention.¹, ², ³, ⁴, ⁵, ⁶, ⁷, ⁸, ⁹, ¹⁰, ¹¹ In Europe this therapy has also shown excellent clinical outcomes in treating fecal incontinence and idiopathic constipation but these indications are not approved in the United States. Many patients treated with SNM experience an immediate clinical benefit that is sustained during long-term followup. Several authors have published their results with SNM, reporting on various followup periods and success rates. As new techniques, devices, and components emerge, analysis of long-term data, particularly those gathered from the original patient groups enrolled in FDA approved studies, is important to advance our knowledge of SNM. This study, one of the earliest and largest prospective, multicenter clinical trials of SNM therapy, has concluded after 5 years of followup. We report here the long-term results.

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Materials and Methods 

This PAS was a prospective, nonrandomized, multicenter, followup study initiated after FDA approval of InterStim therapy. Most of the enrolled patients (129) were already implanted with InterStim system for treatment of UI, UF and nonobstructive urinary retention as part of the multicenter, randomized controlled study (MDT-103) and were consecutively crossed over to the long-term followup study. All 17 ethical committees approved the long-term PAS protocol and each patient signed informed consent before study participation. Of the 23 centers participating in the original randomized study (MDT-103) 6 declined to participate in the PAS and those patients were excluded from further followup.¹, ² No significant differences between patients from the declined and participating centers could be identified.

Patient Selection and Evaluation 

The PAS study enrolled a total of 163 patients. Demographic data for 1 patient were not available. The mean age was 44.7 ± 11.2 years with 21 males (13%) and 141 females (87%). By indication 103 patients (64%) had UI, 28 (17%) had UF and 31 (19%) had complete or incomplete urinary retention. A total of 129 patients crossed over from the MDT-103 study and 34 were enrolled under the new PAS protocol. Of those 34 patients, 23 were implanted with the InterStim system and 11 declined permanent implantation despite a positive response to test stimulation. The 5-year results for all 152 implanted cases are reported.

The PAS study used a patient followup protocol similar to the original MDT-103 study.¹², ¹³ Compared to the MDT-103 study, the PAS required annual followup visits, and used more advanced devices (eg test stimulation leads, implantable neurostimulators) and new techniques (eg neurostimulator implantation in the buttock). The majority of patients had the INS implanted in the abdomen (121) and only 31 patients who were enrolled later on, had the INS implanted in the buttock. The criteria for rating clinical success based on patient voiding diaries and methods for reporting and analyzing AEs remained unchanged. The required data at annual followup visits for all patients who underwent implantation included a voiding diary completed for a minimum of 3 days, and simple uroflow and quality of life questionnaires. The Short Form-36 and the Beck Depression Inventory were used. Detailed data were also collected on any concomitant treatment for the urological condition and on any therapy or patient related complications.

The voiding dysfunction indications (UI, UF and retention) were represented by unique primary voiding diary variables on which therapy outcome was measured. For patients with UI these diary variables include number of leaking episodes daily, number of heavy leaking episodes daily and number of pads used daily. For patients with UF the variables included number of voids daily, volume voided per void and degree of urgency experienced before void. For patients with retention the variables included catheterized volume per catheterization and number of catheterizations daily. InterStim therapy was considered successful if 50% or more improvement occurred in any of primary voiding diary variables compared with baseline. Safety data were reported for all implanted cases. Descriptive summaries were provided for device or therapy related AEs and also those requiring surgical intervention.

Patient Disposition 

In this long-term followup study patients were followed for up for 5 years. Due to the long followup period, some scheduled followup visits were missed and not all patients provided a voiding diary at each followup visit. Table 1 provides a breakdown of the followup elements by patient group (ie number of visits, diaries and explants) at each followup period.

Table 1. Breakdown of followup elements by postimplantation visit

	No. at Followup
	1-Yr	2-Yr	3-Yr	4-Yr	5-Yr
UI:
Visits	87	79	72	69	65
Diaries	71	65	61	57	54
Explants due to complication or lack of efficacy (cumulative)	1	2	3	4	8
Retention:
Visits	27	26	28	28	27
Diaries	27	24	26	19	22
Explants due to complication or lack of efficacy (cumulative)	0	0	0	1	1
UF:
Visits	24	19	16	16	13
Diaries	23	19	14	16	11
Explants due to complication or lack of efficacy (cumulative)	0	2	5	6	7

A total of 138 patients completed 1-year followup and 121 patients completed the 1-year voiding diary. At 5 years a total of 105 patients completed followup and 87 completed the voiding diary. There were 47 patients who did not have 5-year data, and 16 of them had the system explanted and withdrew due to lack of efficacy or complications. The last followup visit with diary data occurred on average at 49.3 months ± 15.9 (range 11 to 60) following implantation for the 145 patients with at least 1 followup diary past 12 months.

Statistical Analysis 

For each of the primary voiding diary parameters relevant for measurement of UI, UF and retention, statistical comparisons were made between baseline and postimplantation using a repeated measure analysis. A clinical success rate (ie percent of patients with 50% or more improvement in the voiding diary variable) at each visit was calculated for each primary voiding diary variable. Patients who exited the study due to an adverse event or lack of efficacy were considered unsuccessful and were assumed to return to their baseline. For patients who missed a study visit or failed to provide the voiding diary at a scheduled visit for other reasons, the last observation carried forward was used to impute missing data. A sensitivity analysis based on all implanted cases with valid followup and diary data were also performed to assess the robustness of the results.

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Results 

Efficacy for Urge Incontinence 

The average number of leaking episodes per day at baseline for patients with UI was 9.6 ± 6.0. This decreased to 4.7 ± 4.9 at 1-year followup and the reduction was maintained throughout followup with an average of 3.9 ± 4.0 at 5 years after implantation (part A of figure). The number of heavy leaks per day decreased from 2.6 ± 3.3 at baseline to 1.2 ± 2.7 at 1-year followup, and to 0.8 ± 1.7 at 5 years after implantation. Patients with urge incontinence also showed a decrease in the number of pads used per day from more than 5 at baseline to 1.8 at 5 years after implantation. A clinical success rate of 58% was observed in number of leaks per day, 68% in number of heavy leaks per day and 61% in number of pads used per day at 5-year followup (table 2).

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• Average voiding diary parameters during 5 years after implantation. A, patients with UI. B, patients with UF. C, patients with retention. Missing values were imputed using last observation carried forward. Except for degree of urgency, voiding parameter changes from baseline were statistically significant (p <0.001) from repeated measure analysis.

Table 2. Clinical success rates for 5 years after implantation by indication and visit

	1-Yr	2-Yr	3-Yr	4-Yr	5-Yr
% UI (No./total No.):
Leaks/day	51(49/96)	60(58/96)	59(57/96)	58(56/96)	58(56/96)
Heavy leaks/day	50(40/80)	61(48/79)	67(52/78)	68(53/78)	68(53/78)
Pads/day	51(45/88)	60(53/89)	54(48/89)	58(50/87)	61(53/87)
% UF (No./total No.):
Voids/day	40(10/25)	48(12/25)	52(13/25)	48(12/25)	40(10/25)
Vol/void	60(15/25)	68(17/25)	64(16/25)	56(14/25)	56(14/25)
Degree of urgency	68(17/25)	72(18/25)	68(17/25)	60(15/25)	56(14/25)
% Rentention (No./total No.):
Catheters/day	68(21/31)	65(20/31)	68(21/31)	68(21/31)	58(18/31)
Vol/catheter	68(21/31)	77(24/31)	77(24/31)	71(22/31)	71(21/31)

Denominator may vary over followup visits due to missing data.

Efficacy for Urgency Frequency 

The average number of voids per day decreased from 19.3 ± 7.0 at baseline to 13.0 ± 7.9 at 1-year followup for patients with UF. The reduction was maintained throughout followup with a slight increase to 14.8 ± 7.6 at 5 years after implantation (part B of figure). The average voided volume increased from 92.3 ± 52.8 ml at baseline to 169.9 ± 118.2 ml 1 year after implantation and effectiveness was maintained throughout the long-term followup period with an average of 165.2 ± 147.7 at 5 years after implantation. Patients with urgency/frequency reported a decrease in degree of urgency per day from 2.3 ± 0.6 at baseline to 1.9 ± 0.8 at 1-year followup and to 2.1 ± 0.7 at 5-year followup. A clinical success rate of 40% was observed in number of voids per day, and 56% in degree of urgency per day at 5 years after implantation for patients with UF, and 56% experienced a 50% or more increase in the average volume voided per void. Of the patients with a successful clinical outcome after 1 year implant 71% remained successful at 5-year followup (table 2).

Efficacy for Urinary Retention 

The average number of catheterizations per day decreased from 5.3 ± 2.8 at baseline to 1.9 ± 2.8, and 58% clinical success rate was observed at 5 years after implantation. The average catheterized volume per catheterization decreased from 379.9 ± 183.8 ml at baseline to 109.2 ± 184.3 ml, and clinical success rate of 71% was observed at 5 years after implantation (part C of figure, table 2).

Of those patients with an unsuccessful therapy outcome, the therapy failure period ranged from 6 to 60 months after implantation with a mean failure period of 24 months for all indications. To assess the robustness of reported results, sensitivity analysis was performed based on all evaluable patients with valid visits and diary data. Consistent results were obtained and, thus, not presented. The quality of life scores (Short Form-36 and Beck Depression Inventory) showed some improvement but this was not statistically significant. Interpretation of these data is limited because of the generic nature of the selected questionnaires which were the only methods available at the time the study was designed.

Safety 

The safety data were reported based on all implanted cases. There were 102 (67%) patients who had at least 1 device or therapy related adverse event. A total of 221 AEs were recorded and most (96%) were resolved by the time the data were analyzed. A total of 110 adverse events required surgery in 60 patients. There were 92 patients analyzed who underwent implantation and did not have adverse events requiring surgical intervention. Overall the system was explanted from 16 patients due to adverse event or lack of efficacy.

Of the adverse events in 102 patients 31 were device related (24 patients, 15.8%) and 240 were therapy related (97 patients, 63.8%) (table 3). Among the therapy related events the most frequently reported event was new pain or undesirable change in stimulation, which occurred 60 times in 41 patients (27.0% of all patients). Pain at PNE or the implant site related to the INS was the second most commonly reported event, occurring 40 times in 30 patients (19.7% of all patients). Of all device related adverse events, the most frequently reported were suspected device problems (5.3%) and suspected lead migration (3.3%) (table 3).

Table 3. Device or therapy related adverse events

	Device Related		Therapy Related
	No. Pts With AEs (%)	No. Cumulative AEs	No. Pts With AEs (%)	No. Cumulative AEs
New pain/undesirable change in stimulation	2 (1.3)	2	41 (27.0)	58
Pain at PNE or implant site — INS	1 (0.7)	1	29 (19.1)	39
Infection at PNE or implant site	0	0	12 (7.9)	14
Pain at PNE or implant site — lead	0	0	12 (7.9)	13
Sensation of electric shock	2 (1.3)	2	10 (6.6)	12
Undesirable change in voiding function	0	0	11 (7.2)	12
Lead migration	5 (3.3)	5	8 (5.3)	9
Technical problems during PNE/implant	0	0	8 (5.3)	8
Device problem	8 (5.3)	11	8 (5.3)	8
Other	7 (4.6)	10	44 (29.0)	67
Overall	24 (15.8)	31	97 (63.8)	240

Throughout the 5-year followup surgical intervention was required to resolve adverse events in 60 patients (110 events). Device exchange, which included replacement of a lead, extension or INS, was the most common intervention, resulting from 52 adverse events in 36 patients (23.7%). The types of surgical interventions performed are shown in table 4, including the percentage of patients who experienced an adverse event requiring those interventions. These figures include a group of patients who had an INS exchange because of battery depletion. A total of 60 (39.5%) patients experienced adverse event requiring surgical intervention with 36 (23.7%) requiring device exchange. Of the 152 patients treated with implantation 92 (60.5%) did not have an adverse event requiring surgical intervention.

Table 4. Device or therapy related adverse events requiring surgical intervention

	No. Pts With AEs (%)	No. Cumulative AEs
Device exchange	36 (23.7)	52
Reposition implantable pulse generator	12 (7.9)	16
Reposition lead + implantable pulse generator	10 (6.6)	14
Reposition lead	10 (6.6)	12
Permanent explant	9 (5.9)	10
Temporary explant	2 (1.3)	2
Other surgical intervention	2 (1.3)	2
Bilat implant	1 (0.7)	1
Surgical wound care	1 (0.7)	1
Any adverse event	60 (39.5)	110

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Discussion 

This long-term, prospective, multicenter, FDA regulated study represents the most comprehensive followup study of sacral neuromodulation therapy with the largest patient population to be analyzed or published to date. The efficacy data confirm sustained clinical benefit of sacral neuromodulation that has been shown in various patient populations reported in recent years.², ⁹, ¹⁰, ¹⁴ A drawback of such a long-term trial is that it cannot assess new therapeutic advancements that occur after the study begins, which may potentially affect patient selection, procedure techniques, devices used and overall patient outcomes. Another disadvantage of this study is the missing data due to patients not attending at scheduled visits or becoming lost to followup. Therefore, clinical implication from this study should be interpreted with caution although a sensitivity analysis was performed based on all evaluable data. Nonetheless, this long-term study demonstrates that approximately 70% of the treated patients continued to experience therapeutic benefit after 5 years of the treatment. The approximately 30% of the patients who did not benefit from the treatment between 6 and 24 months of followup is consistent with previously published literature.¹⁰

Many possible explanations exist for treatment failure, including potential placebo effect of test stimulation, insufficient test stimulation sensitivity before implantation and inadequate patient selection (eg severe disease state at study enrollment, presence of specific mental conditions and previous sociomedical history). For instance Weil et al, reporting on their long-term results in 36 patients, found a striking correlation between secondary loss of therapeutic effect and the presence of preexisting psychiatric disorders in the medical history.⁹ However, the effect of psychiatric disorders on the efficacy of neuromodulation has not been established.

An important finding in this study is the high correlation between 1 and 5-year success rates for treated patients. There were 84% of patients with UI, 71% with UF and 78% with urinary retention who were successfully treated at 1-year followup and continued to have a successful outcome at 5 years after implantation.

SNM has proved to be safe therapy that does not preclude any other treatment options. The midterm safety profile of SNM was established in the original MDT-103 study with 219 implanted cases.¹² No reports of any life threatening or irreversible adverse events have been made in this or any previous studies of neuromodulation for urinary conditions. Of the 271 reported adverse events 110 required surgery in 60 patients. The most common surgical interventions were device exchange or device repositioning, which are generally considered minor surgical procedures. Pain at PNE or implant site necessitating surgical intervention was the most common indication occurring in 11.8% of implanted cases throughout the course of the study. The second and third most common indications requiring surgical intervention were suspected lead migration and new pain or undesirable change in stimulation. As 12 of the 14 patients experiencing these adverse events had undergone implantation with an older Itrel II^® INS, which has been superseded by the new InterStim INS, the midterm and long-term number of device related surgical interventions is expected to decrease. INS exchange due to battery depletion will continue to occur on average every 8 years. (InterStim Therapy [package insert], Minneapolis, Minnesota: Medtronic, Inc. 1997, 1999.) However, this is a minor intervention performed on an outpatient basis with the patient under local anesthesia.

In 1999 the placement of the INS was changed from the abdomen to the buttock because buttock placement resulted in less pain and fewer infections postoperatively, which minimized the need for INS repositioning, and reduced operating time.¹⁵ Despite lack of randomized controlled trials on effect of buttock vs abdominal placement and its impact on the rate of surgical reoperation, clinical data seems to confirm a convincingly reduced rate of INS related complaints. Analysis of the occurrence of surgically corrected adverse events in both treatment groups in our study revealed that the reoperation rate due to pain at the INS site decreased in cases of buttock placement. The difference was not statistically significant due to the relatively small number of patients who were enrolled in the study with the buttock neurostimulator implant.

At 1-year followup 19.9% of the patients had adverse event resulting in surgical intervention, which increased to 42.1% by 5-year followup. Of 152 implanted cases 92 did not have an adverse event requiring surgical intervention. Although this is a relatively high number we emphasize that this was the first study in which SNM therapy was offered to quite severely affected patients and with a steep learning curve.

It should also be noted that patients who experienced loss of therapeutic effect often underwent revision surgery because it was believed at the time that new lead placement or switching to the contralateral side would restore benefit. Revision surgeries were performed and repeated on each patient when a technical problem occurred, the device had to be replaced, or when pain complaints indicated a problem. A later study demonstrated that loss of therapeutic effect often cannot be resolved with revision surgery.¹⁴

Patient selection and the SNM operating technique involved a steep learning curve. Some of the devices and surgical techniques used early in the study have been replaced by major advancements within the last 3 years. For example, the technique has become minimally invasive with use of a percutaneous tined lead placement with the patient under local anesthesia that allows patient participation to help determine sensory responses.

Reported adverse event rates from recent literature are between 11% and 22%. Specifically for surgical revision, the rates range from 7% to 18% with followup from 7 to 24 months.¹⁶, ¹⁷, ¹⁸ This clearly demonstrates a reduction in the adverse event rate with the new technology (minimally invasive technique and use of the tined lead and upper buttock INS placement).

Much has been learned at each center regarding the requirements for success, including the need for experienced personnel and appropriate hospital setup for optimal therapy delivery. These improvements are now being practiced in all centers providing SNM therapy.

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Conclusions 

This long-term study dramatically advanced overall knowledge of sacral neuromodulation therapy for urinary dysfunction. The results show that sacral neuromodulation safely and effectively provides long-term relief for appropriately selected patients with refractory UI, UF and urinary retention. SNM is a safe, reversible, minimally invasive method that may be an appropriate alternative to more invasive techniques for well selected patients. Although much has been learned, methods can still be optimized. Further research is warranted to elicit the mechanism of action, to improve patient selection and the sensitivity of percutaneous test stimulation, and to avoid adverse events after implantation.

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References 

1. Siegel SW. Management of voiding dysfunction with an implantable neuroprosthesis. Urol Clin North Am. 1992;19:163
   • View In Article
   • MEDLINE
2. Hassouna MM, Siegel SW, Nyeholt AA, Elhilali MM, van Kerrebroeck PE, Das AK, et al. Sacral neuromodulation in the treatment of urgency-frequency symptoms: a multicenter study on efficacy and safety. J Urol. 2000;163:1849
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (588 KB)
   • CrossRef
3. Dijkema HE, Weil EH, Mijs PT, Janknegt RA. Neuromodulation of sacral nerves for incontinence and voiding dysfunctions (Clinical results and complications). Eur Urol. 1993;24:72
   • View In Article
   • MEDLINE
4. Bosch JL, Groen J. Sacral (S3) segmental nerve stimulation as a treatment for urge incontinence in patients with detrusor instability: results of chronic electrical stimulation using an implantable neural prosthesis. J Urol. 1995;154:504
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (823 KB)
   • CrossRef
5. Hasan ST, Shanahan DA, Pridie AK, Neal DE. Surface localization of sacral foramina for neuromodulation of bladder function (An anatomical study). Eur Urol. 1996;29:90
   • View In Article
   • MEDLINE
6. Hasan ST, Robson WA, Pridie AK, Neal DE. Transcutaneous electrical nerve stimulation and temporary S3 neuromodulation in idiopathic detrusor instability. J Urol. 1996;155:2005
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (927 KB)
   • CrossRef
7. Shaker HS, Hassouna M. Sacral root neuromodulation in idiopathic nonobstructive chronic urinary retention. J Urol. 1998;159:1476
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (491 KB)
   • CrossRef
8. Shaker HS, Hassouna M. Sacral nerve root neuromodulation: an effective treatment for refractory urge incontinence. J Urol. 1998;159:1516
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (557 KB)
   • CrossRef
9. Weil EH, Ruiz-Cerda JL, Eerdmans PH, Janknegt RA, Van Kerrebroeck PE. Clinical results of sacral neuromodulation for chronic voiding dysfunction using unilateral sacral foramen electrodes. World J Urol. 1998;16:313
   • View In Article
   • MEDLINE
   • CrossRef
10. Bosch JL, Groen J. Sacral nerve neuromodulation in the treatment of patients with refractory motor urge incontinence: long-term results of a prospective longitudinal study. J Urol. 2000;163:1219
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (193 KB)
    • CrossRef
11. Koldewijn EL, Rosier PF, Meuleman EJ, Koster AM, Debruyne FM, van Kerrebroeck PE. Predictors of success with neuromodulation in lower urinary tract dysfunction: results of trial stimulation in 100 patients. J Urol. 1994;152:2071
    • View In Article
    • MEDLINE
12. Siegel SW, Catanzaro F, Dijkema HE, Elhilali MM, Fowler CJ, Gajewski JB, et al. Long-term results of a multicenter study on sacral nerve stimulation for treatment of urinary urge incontinence, urgency-frequency, and retention. Urology. 2000;56:87
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (132 KB)
    • CrossRef
13. Janknegt RA, Hassouna MM, Siegel SW, Schmidt RA, Gajewski JB, Rivas DA, et al. Long-term effectiveness of sacral nerve stimulation for refractory urge incontinence. Eur Urol. 2001;39:101
    • View In Article
    • MEDLINE
    • CrossRef
14. Everaert K, De Ridder D, Baert L, Oosterlinck W, Wyndaele JJ. Patient satisfaction and complications following sacral nerve stimulation for urinary retention, urge incontinence and perineal pain: a multicenter evaluation. Int Urogynecol J Pelvic Floor Dysfunct. 2000;11:231
    • View In Article
    • MEDLINE
    • CrossRef
15. Scheepens WA, Weil EH, van Koeveringe GA, Rohrmann D, Hedlund HE, Schurch B, et al. Buttock placement of the implantable pulse generator: a new implantation technique for sacral neuromodulation–a multicenter study. Eur Urol. 2001;40:434
    • View In Article
    • MEDLINE
    • CrossRef
16. Starkman JS, Wolter CE, Scarpero HM, Milam DF, Dmochowski RR. Management of refractory urinary urge incontinence following urogynecological surgery with sacral neuromodulation. Neurourol Urodyn. 2007;26:29
    • View In Article
    • MEDLINE
    • CrossRef
17. Van Voskuilen AC, Oerlemans DJ, Weil EH, van den Hombergh U, van Kerrebroeck PE. Medium-term experience of sacral neuromodulation by tined lead implantation. BJU Int. 2007;99:107
    • View In Article
    • MEDLINE
    • CrossRef
18. Kessler TM, Buchser E, Meyer S, Engeler DS, Al-Khodairy AW, Bersch U, et al. Sacral neuromodulation for refractory lower urinary tract dysfunction: results of a nationwide registry in Switzerland. Eur Urol. 2007;51:1357
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (236 KB)
    • CrossRef