Sacral root neuromodulation in the treatment of various voiding and storage problems

Current role of neuromodulation in bladder pain syndrome/interstitial cystitis

Neuromodulation is recommended by major international guidelines as a fourth-line treatment in bladder pain syndrome/interstitial cystitis (BPS/IC) patients after failure of behavioural, oral and intravesical pharmacological treatments, including hydrodistension. A non-systematic review of studies identified by electronic search of MEDLINE was performed with no time limitation. A narrative synthesis of the existing evidence regarding the results of sacral, tibial and pudendal nerve stimulation in the management of BPS/IC was developed. Neuromodulation in pelvic chronic pain disorders, including BPS/IC, is a useful tool for refractory patients to conventional treatments. Sacral neuromodulation may be effective in patients with BPS without Hunner's lesions, and the effect seems to be maintained in the mid- and long-term. Posterior tibial nerve stimulation can be offered to patients with BPS/IC in the context of a multidisciplinary approach. When pudendal neuralgia is suspected, selective pudendal nerve stimulation has a high response rate. The aetiology of the pain can influence the outcomes in the mid- and long-term of the different neuromodulation approaches, thus careful diagnosis is recommended.

Long-term Outcomes of Sacral Nerve Stimulation in Pelvic Floor Dysfunctions

Purpose

The aim of this study was to analyze the long-term outcomes of sacral nerve stimulation (SNS) in both idiopathic and neurogenic pelvic floor disorders in patients treated at a referral center.

Methods

This retrospective observational study analyzed the records of 106 patients tested at our department from December 1999 to January 2017. The efficacy variables evaluated were the Global Response Assessment (range, 0%–100%) and, according to the clinical indication, other specific variables such International Consultation on Incontinence QuestionnaireShort Form, number of catheterizations or pads/day, and the numerical pain scale. The safety variables analyzed were complications (pain, migration, infection), reinterventions and explants. Patients’ quality of life (QoL) and satisfaction with the procedure were evaluated through telephone interviews.

Results

The clinical indications were overactive bladder (OAB) (n=36), urinary retention (UR) (n=37), bladder pain syndrome/interstitial cystitis (BPS/IC) (n=19), fecal incontinence (FI) (n=8), and double incontinence (DI) (n=6). The implant rates according to the clinical indication were as follows: OAB, 55.6%; UR, 56.8%; BPS/IC, 63.15%; FI, 87.5%; and DI, 66.7%. Clinical and/or statistically significant improvements in all efficacy variables were observed. Loss of therapeutic effect at 75 months of follow-up was observed in 34% of patients. Device-related pain appeared in 25 patients (39%); in 20 patients, it was resolved by reprogramming and 5 patients required device removal. An overall improvement in QoL and high levels of satisfaction with the procedure were observed. More than 90% of patients would recommend SNS to a friend or relative.

Conclusions

SNS is a minimally invasive procedure that offers a real alternative to patients with refractory pelvic floor dysfunction. Its safety profile is very favorable and it provides a long-lasting improvement in symptoms and QoL.

A Cadaveric Study on the Efficacy of Surface Marking and Bony Landmarks Used in Sacral Neuromodulation

Background

Anatomical landmarks and surface markings have long been used in out-patient contexts for conducting percutaneous nerve evaluation procedures, but studies testing the reliability of these anatomical landmarks are scant. There have been reports where the procedure has failed. Could it be possible that the anatomical landmarks that are used are not reliable enough? To answer this question, we used this study to understand the reliability of these anatomical landmarks.

Methods

Twenty cadavers, 10 males and 10 females, were dissected in the sacral region; the landmarks were tested, and the angulation and curve made by the sacral 3 (S3) nerve were also studied.

Results

Sacral 3 was identified mainly at the four o’clock position on the right and at the eight o’clock position on the left side. The Sacral 3 foramen was found at a mean distance of 9.17 ± 0.23 cm from the tip of the coccyx. The mean distance of the lateral margin of S3 from the median sacral ridge was found to be 2.16 ± 0.07 cm.

Conclusion 

The landmark of 9 cm from the coccyx tip is a valid landmark for sacral neuromodulation (SNM) procedures. The tip of the lead should follow the curve of the nerve as close as possible at the four and eight o’clock positions on the right and left side, respectively. However, the length of the coccyx differs from person to person. The proximity of the adjacent foramina to each other and the variations in the emerging of the nerve are a few factors to be considered while performing SNM procedures. Further study with a larger sample is required in order to investigate the course of the nerve, and its relationship to response to SNM.

Long-term anodal block stimulation at sacral anterior roots promoted recovery of neurogenic bladder function in a rabbit model of complete spinal cord injury

A complete spinal cord injury model was established in experimental rabbits using the spinal cord clip compression method. Urodynamic examination was performed 2 weeks later to determine neurogenic bladder status. The rabbits were treated with anodal block stimulation at sacral anterior roots for 4 weeks. Electrical stimulation of sacral anterior roots improved urodynamic parameters of neurogenic bladder in rabbit models of complete spinal cord injury, effectively promoted urinary function, and relieved urinary retention. Immunohistochemistry results showed that a balance was achieved among expression of muscarinic receptor subunits M2, M3, ATP-gated ion channel P2X3 receptors, and β2-adrenergic receptor, and nerve growth factor expression decreased. These results suggested that long-term sacral anterior root stimulation of anodal block could be used to treat neurogenic bladder in a rabbit model of complete spinal cord injury.

Surface and boney landmarks for sacral neuromodulation: a cadaveric study

INTRODUCTION AND HYPOTHESIS

Standard external landmarks have been suggested as a guide for in-office percutaneous nerve evaluation (PNE), but validity of these landmarks has not been assessed. Our objective was to determine whether the standard 9 cm from the tip of the coccyx indicates the position of the S3 sacral foramen and whether other boney landmarks and measurements improved positioning.

METHODS

Measurements and distances between external boney landmarks were obtained in 22 embalmed cadavers. Spinal needles were placed 9 cm superior to the coccyx and 2 cm lateral to midline bilaterally. After dissection, internal measurements relating to sacral length, position of S3, and location of the needle in relation to S3 were recorded. Correlations among measured variables were assessed using descriptive statistics.

RESULTS

Mean distance from the tip of coccyx to S3 was 9.26 cm (±0.84), from S3 to midline 2.30 cm (±0.2); from needle to S3 1.25 cm, and needle placement was as likely to be placed above or below S3; and S2-S3 and S3-S4 interforamenal distance 1.48 cm (±0.30) and 1.48 cm (±0.24), respectively. Mean distance from S3 to sacroiliac joint (SIJ) was shorter than S2 to SIJ. All associations between external measurements and length from tip of coccyx to S3 were not significant.

CONCLUSION

A distance 9 cm from the tip of the coccyx is a reasonable starting landmark for in-office blind PNE. However, given the variability in coccyx length, caution should be taken; also, sensory-motor response is necessary to confirm proper placement.

Efficacy of sacral neuromodulation in treating chronic pain related to painful bladder syndrome/interstitial cystitis in adults

OBJECTIVE

The objective of this review is to evaluate the efficacy and safety of sacral neuromodulation in treating chronic pelvic pain related to Painful bladder syndrome/Interstitial-cystitis.

DESIGN

The databases searched were MEDLINE and EMBASE [1950- Nov 2011]. Additional searches were performed on the Cochrane Database of Systematic reviews (CDSR), Scopus, CINAHL, BIOSIS, The Cochrane controlled trials register, the science citation index, TRIP DATABASE.

RESULTS

Overall 70.8% or 170/244 patients were successful at the trial stage. The only randomized controlled trial reported a decrease in Visual analogue pain scores of 49% (7.9 to 4.0) for sacral nerve stimulation [SNS] and 29%(4.5 to 3.2) for pudendal nerve stimulation [PNS] at 6 months follow up. Nine observational studies reported a decrease in pain scores/decrease in pain medications at long term follow up following permanent sacral neuromodulation. One study showed an 80% improvement in Global response assessment score.

CONCLUSION

The results from the randomised controlled trial and case series/case reports demonstrate a reduction of pain symptoms of Painful bladder syndrome following sacral neuromodulation.

Urinary retention in women and sacral neuromodulation

The remit of this article is to provide an overview of urinary retention in women, taking into account the predisposing factors, aetiology, investigations and treatments. The information presented is based on a widespread search of the English literature using multiple library sites on the internet and on personal experience. Urinary retention occurs when there is impaired bladder emptying, resulting in a high post-void urinary residual. It is often associated with restricted voiding. The aetiology is manifold and thus the symptomatic patient may present to the urologist, gynaecologist, neurologist or physician. Once the problem is identified, and predisposing factors excluded (e.g. opiates), the patient has to be investigated fully. In the Department of Uro-Neurology at the National Hospital for Neurology and Neurosurgery in the UK, we advocate the use of urethral sphincter assessments, including urethral pressure studies, ultrasound volume assessment and electromyography. This article will take a detailed look at all aspects of assessing these patients. In those in whom diagnosis is reached, sacral neuromodulation (SNM) is the treatment of choice. As a modality, SNM has its supporters but also its detractors. Thus, it is essential that all patients are fully counselled before undergoing this surgery. Urinary retention in women is still poorly understood. This article serves to demystify the issues raised in having this condition, by looking closely at the currently known science. It is clear that some patients may be diagnosed with Fowler's syndrome and may thus be more treatable by SNM than others, but this still leaves a significant proportion of patients with no diagnosis and no satisfactory therapy. A great deal of work still needs to be done on the understanding of the pathogenesis, the provision of more distinct investigations and the development of better treatment modalities.

Sacral neuromodulation with implanted devices for urinary storage and voiding dysfunction in adults

BACKGROUND

The neural control of storage and voiding of urine is complex and dysfunction can be difficult to treat. One treatment for people with refractory symptoms is continuous electrical nerve stimulation of the sacral nerve roots using implanted electrodes and an implanted pulse generator.

OBJECTIVES

To determine the effects of implantable electrical stimulation devices in the treatment of urine storage and voiding problems.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Register (searched 10 February 2009), CENTRAL (The Cochrane Library 2008, Issue 1), MEDLINE (January 1980 to March 2008), EMBASE (January 1980 to March 2008), CINAHL (January 1982 to March 2008) and the reference lists of relevant articles.

SELECTION CRITERIA

Trials that tested implanted electronic stimulators connected to electrodes attached to the nerves and providing continuous electrical stimulation for neuromodulation.

DATA COLLECTION AND ANALYSIS

Both authors selected studies, assessed quality, and extracted data.

MAIN RESULTS

Eight reports of randomised studies that evaluated implants which provided continuous stimulation were included. It was unclear whether some reports included patients who also appeared in other reports, so no data were pooled. In spite of this, it seems clear that continuous stimulation offers benefits for carefully selected people with overactive bladder syndrome and for those with urinary retention but no structural obstruction.Many of the implants did not work and many required revision operations. Many questions remain about patient selection and the best way to use these devices.

AUTHORS' CONCLUSIONS

In spite of methodological problems, it would appear that some people benefit from implants which provide continuous nerve stimulation. More research is needed on the best way to improve patient selection, carry out the implant, and to find why so many fail. The effectiveness of implants should be tested against other interventions, particularly in people with an overactive bladder.

Spinal nerve root stimulation

Spinal nerve root stimulation is a recently developed form of neuromodulation used for the treatment of chronic pain conditions. Unlike spinal cord stimulation, in which electrical impulses are directed at the dorsal columns, spinal nerve root stimulation guides electrical current directly to one or more nerve roots. There are a variety of techniques by which this can be accomplished, yet no consistent terminology to describe these variations exists. In this review, the authors group the various techniques according to anatomical approach, define each category, describe and illustrate each of the techniques, review the available reports on their uses, and discuss the advantages and disadvantages of each one.

[Sacral root neuromodulation. Experience in our site: 1998-2003, concerning 18 definite neuromodulation implants]

OBJECTIVE

Sacral root neuromodulation is an effective technique for the treatment of Chronic Micturition Dysfunction (CMD) refractory to conventional therapy. New indications such as chronic pelvic pain and interstitial cystitis are currently making their way within the urologic setting. Several groups of gastric surgeons are now choosing this technique for the management of rectal diseases (constipation, sphincter dysfunction). This paper contributes our experience in the treatment of patients with CMD and the comparative results at one year from implant in all patients.

MATERIAL AND METHODS

From December 1998 through July 2003, 18 neuromodulation definite implants were performed. The main indication was CMD in 62.5% patients. Follow up of patients was done at one month and three months, and every six months thereafter. Follow up is conducted through a micturition diary and QoL questionnaire. Electrode implant in the first 16 patients was achieved by open surgery. The next 2 patients had the electrode placed by a percutaneous technique using the "Tined Lead" kit.

RESULTS

Results at one year after implant were compared in all patients. The total number of neuromodulation implants placed was 18, 14 (77.7%) of which were women and 4 (22.3%) men. Mean age was 52.56 years. Implant indication was CMD in 72.2% patients, mixed incontinence (urinary and faecal) in 22.1%, and interstitial cystic disease in 5.5%. Symptoms improvement at one year from implant, as determined by a micturition diary and QoL questionnaire was 76.4%. Clinical improvement was greater in patients with urgency symptoms than in patients with predominance of voiding symptoms.

Update on sacral neuromodulation: Indications and outcomes

Tanagho and Schmidt first introduced sacral nerve neuromodulation in 1981. Since then, it has become increasingly popular and the indications for this procedure are growing. The purpose of this article is to discuss the established indications for sacral nerve stimulation (SNS). The outcomes of the most recent studies and trials dealing with SNS are presented. An overview of the most recent techniques used for neuromodulation is detailed.

Modified techniques of S3 foramen localization and lead implantation in S3 neuromodulation

INTRODUCTION

We describe a reproducible and less invasive surgical approach to sacral neuromodulation (InterStim Therapy) in the treatment of voiding dysfunction. Twenty patients underwent modified lead implantation (mean operative time 45 minutes) without any difficulties or complications, with a mean follow-up of 8 months (range 1 to 14).Technical Considerations. The highlights of these modifications include (a) fluoroscopy to localize the S3 foramen; (b) paramedian incision; (c) use of a cutoff S3 finder needle and a 14-gauge Angiocath to direct permanent lead into the S3 foramen without dissection; (d) use of lateral fluoroscopy to determine the depth of the Angiocath insertion; and (e) anchoring the lead to the lumbodorsal fascia (superficial to the sacral periosteum) using a moveable lead anchor system. These modifications simplify and minimize the invasiveness of this therapy without compromising the efficacy.

CONCLUSIONS

Because of the simplicity of these modifications, we are currently using an implanted lead, rather than the temporary percutaneous lead, to assess patients' clinical response before implanting a pulse generator.

Sacral nerve stimulation in patients with chronic intractable pelvic pain

PURPOSE

Transforamenal sacral nerve stimulation with an implantable neuroprosthetic device has been shown to benefit patients with chronic voiding dysfunction. In this study we measured the effectiveness of sacral nerve stimulation in 10 patients with chronic intractable pelvic pain.

MATERIALS AND METHODS

After successful percutaneous trial stimulation, a neuroprosthetic sacral nerve stimulation device was surgically implanted in 10 patients with chronic intractable pelvic pain. Leads were placed in the S3 and S4 foramen in 8 and 2 cases, respectively. Patients were evaluated throughout the study using a patient pain assessment questionnaire on a scale of 0-absent to 5-excruciating pain. Pain was assessed at baseline, during test stimulation, and 1, 3 and 6 months after surgical lead implantation. An additional long-term assessment was done at a median followup of 19 months.

RESULTS

Of the 10 patients with the implant 9 had a decrease in the severity of the worst pain compared to baseline at a median followup of 19 months. The number of hours of pain decreased from 13.1 to 6.9 at the same followup interval. There was also an average decrease in the rate of pain from 9.7 at baseline to 4.4 on a scale of 10-always to 0-never having pain. At a median of 19 months 6 of 10 patients reported significant improvement in pelvic pain symptomology.

CONCLUSIONS

These data imply that transforamenal sacral nerve stimulation can have beneficial effects on the severity and frequency of chronic intractable pelvic pain. Future clinical studies are necessary to determine the long-term effectiveness of this therapy.

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.

Pharmacologic and potential biologic interventions to restore bladder function after spinal cord injury

Spinal cord injury disrupts voluntary control of voiding and the normal reflex pathways that coordinate bladder and urethral sphincter function. The present review addresses studies in animals and humans that have evaluated various therapeutic approaches for normalizing lower urinary tract function after spinal cord injury.