Early versus late treatment of voiding dysfunction with pelvic neuromodulation

Introduction:

Pelvic neuromodulation is an established method of treating voiding dysfunction. Little is known about the pathophysiology associated with voiding dysfunction. Reports have suggested that a delay in treating patients with sacral neuromodulation therapy can impact the success rate of this type of treatment in voiding dysfunction. We examined patient response to pelvic neuromodulation when it was applied early versus late in the postdiagnosis of voiding dysfunction.

Methods:

We conducted a retrospective study of 42 patients (38 women and 4 men) with voiding dysfunction who underwent surgery for implant with the Interstim (Medtronic, Minneapolis, Minn.). Prior to implantation, patients were required to pass a percutaneous nerve evaluation (PNE) over a 1-week period. Patients were observed for 20–48 months postimplantation. All patients recorded their voiding parameters at baseline, after screening and every 6 months thereafter. Twenty patients (in the early group) underwent implant surgery with the neurostimulator 2–4 weeks post-PNE, and 22 patients (the late group) had the device implanted 6–24 months post-PNE owing to local logistical circumstances.

Results:

In the early group, 16 of 20 patients (80%) maintained a good response. In the late group, 13 of 22 (59%) patients showed a good response. Groups were well matched in terms of age, duration of voiding dysfunction and incidence of comorbidity.

Conclusion:

Patients who were delayed more than 6 months in receiving the neurostimulator implant showed a worse response than did patients who had the device implanted soon after PNE. This indicates the possibility of disease progression, which may limit the response to sacral neuromodulation.Sacral neuromodulation (SNM), using permanent foramen S3 electrode, offers an alternative treatment for patients with conditions refractory to conventional measures. SNM has been approved by the US Food and Drug Administration for 3 indications: urge incontinence (UI), urge frequency (UF) and nonobstructive urinary retention. Several reports have been published regarding the efficacy of SNM in the treatment of UI, UF and nonobstructive urinary retention.^1–4SNM is considered a minimally invasive procedure, and when compared with the more drastic procedures to control intractable overactive bladder symptoms, SNM has fewer complications and has provided patients with more durable and consistent bladder control over time.The purpose of the current study is to determine whether a delay in SNM can affect the long-term outcome of treatment in patients with voiding dysfunction.     

The effect of sacral neuromodulation on pregnancy: a systematic review

Introduction and hypothesis

To evaluate the effects of sacral neuromodulation (SNM) on pregnancy and the impact of delivery on SNM function.

Methods

A systematic search was conducted through January 2016. We selected studies including women who had SNM and a subsequent pregnancy.

Results

Out of 2,316, eight studies were included, comprising 22 patients (26 pregnancies). SNM indications were Fowler’s syndrome in 11, urinary retention in 6, fecal incontinence in 1, fecal and urinary urgency in 1, overactive bladder in 1, intractable interstitial cystitis in 1, and myelodysplasia in 1. SNM stayed on in 8 pregnancies. In the remaining 18 pregnancies in which the device was deactivated, 7 had recurrent urinary tract infections, including 1 with pyelonephritis and 2 who requested reactivation owing to recurrent symptoms. Outcomes were reported in 25 pregnancies, 16 had Cesarean section (CS) and 9 had vaginal delivery, including 2 operative deliveries. Out of 25, two infants had pilonidal sinus and motor tic disorder (exhibited at the age of 2 years), both from the same mother. After delivery, SNM was functioning in 15 (60%), 4 required reprogramming, and 3 required replacement (1 had recurrence of fecal incontinence after her operative delivery with evidence of displaced leads and 1 patient reported decreased SNM effects after her two CS), and 3 decided to remove the device (2 out of 3 patients were free of symptoms after SNM deactivation and requested removal).

Conclusion

Within the current limited evidence, the decision regarding SNM activation or deactivation should be individualized. A registry for those patients is recommended.

     

Unilateral versus bilateral sacral neuromodulation in patients with chronic voiding dysfunction

PURPOSE: Bilateral sacral nerve neuromodulation has been proposed as a more effective treatment for chronic voiding dysfunction. However no comparison with the unilateral approach has been performed. We investigated the possible advantage of bilateral sacral neuromodulation. MATERIALS AND METHODS: In a prospective randomized crossover trial we investigated 33 patients who underwent bilateral implantation of a temporary test lead. Unilateral and bilateral test stimulation was continued for 4 to 6 days in all patients. Patients were randomly assigned to start with bilateral or unilateral stimulation. Between the stimulation episodes a 2-day washout interval was scheduled. Voiding diaries were completed at baseline and during the entire stimulation period. Sacral x-rays were taken to confirm lead positioning or possible migration after implantation and at the end of the test stimulation period. After 10 days the temporary leads were removed and voiding diaries were analyzed. RESULTS: After stimulation sacral x-ray revealed test lead migration in 8 patients, leaving 12 patients with urge incontinence and 13 with voiding difficulty and urinary retention available for review. A statistically significant improvement in voiding parameters was seen during the test stimulation period. However no statistically significant improvement was seen due to bilateral stimulation compared to unilateral stimulation. Two patients with urinary retention only started voiding to completion during bilateral stimulation. CONCLUSIONS: Bilateral is in general not superior to unilateral sacral neuromodulation. However, in some individuals bilateral stimulation may be more effective in relieving symptoms. Therefore, if unilateral percutaneous nerve evaluation fails, a bilateral test should be considered.     

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.     

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.     

Complications and troubleshooting of sacral neuromodulation therapy

As evident from the authors' series, the complications of sacral neuromodulation have changed with the introduction of the tined lead and the placement of the generator over the back. In the earlier series, most complications were related to pain at the generator site, which was rare in the authors' series. The posterior location of the generator seems to be better tolerated than the anterior location, which could explain the rare need for revisions for pain at the generator site. Lead migration was observed in 8.4% of the original sacral neuromodulation study group series. This was seen rarely in the authors' series in either stage-one or stage-two revisions. As part of the routine work-up of patients who present with decreased function after a successful period response in stage two, the authors obtain a lateral radiograph of the sacrum; the authors have made the diagnosis of lead migration rarely (1/130; 0.6%). Spinelli and colleagues reported on the use of the tined lead in 15 patients, and observed no lead migration during either the screening period (average 38.8 days) or during follow-up of IPG implantation cases (average 11 months). The total infection rate in the whole series was 18/180 (10%), which was slightly higher than that reported by the sacral neuromodulation study group (6.1%). Revision rates for stage one and stage two were 12.2% and 20%, respectively. The revision rate in the original study group was 33.3%. Thus, with advancing technology, new problems may arise, but the implanting physician should be aware of the ways to evaluate and manage these complications and appropriately troubleshoot patients with suboptimal responses.     

Lead migration after sacral neuromodulation: surgical revision in fascial versus tined anchoring systems

Introduction and hypothesis  

Our objective was to compare risk of surgical revision after sacral neuromodulator lead migration based on the type of anchoring system.     

Early sacral neuromodulation ameliorates urinary bladder function and structure in complete spinal cord injury minipigs

Aims

To determine the effects of early sacral neuromodulation (SNM) and pudendal neuromodulation (PNM) on lower urinary tract (LUT) function, minipigs with complete spinal cord injury (cSCI) were analyzed. SNM and PNM have been proposed as therapeutic approaches to improve bladder function, for example after cSCI. However, further evidence on efficacy is required before these methods can become clinical practice.

Methods

Eleven adults, female Göttingen minipigs with cSCI at vertebral level T11-T12 were included: SNM (n = 4), PNM (n = 4), and SCI control (SCIC: n = 3). Tissue from six healthy minipigs was used for structural comparisons. Stimulation was started 1 week after cSCI. Awake urodynamics was performed on a weekly basis. After 16 weeks follow-up, samples from the urinary bladder were taken for analyses.

Results

SNM improved bladder function with better capacities and lower detrusor pressures at voiding and avoided the emergence of detrusor sphincter dyssynergia (DSD). PNM and untreated SCI minipigs had less favorable outcomes with either DSD or constant urinary retention. Structural results revealed SCI-typical fibrotic alterations in all cSCI minipigs. However, SNM showed a better-balanced distribution of smooth muscle to connective tissue with a trend towards the reduced progression of bladder wall scarring.

Conclusion

Early SNM led to an avoidance of the emergence of DSD showing a more physiological bladder function during a 4 month follow-up period after cSCI. This study might pave the way for the clinical continuation of early SNM for the treatment of neurogenic LUT dysfunction after SCI.

     

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.     

Current opinion: complications and troubleshooting of sacral neuromodulation

The complications of sacral neuromodulation have been minimized as technology has improved. The main surgical complication remains to be surgical site infection. We review evidence-based suggestions and procedure-specific techniques that reduce the infection rate to less than 2%. In the past, surgical revision was reported as high as 40%. The current revision rate at Mayo Clinic Florida is 10%. The most common reason for surgical revision is either battery end-of-life or loss of effectiveness. We review the best practices of the procedure and a systematic approach to troubleshoot loss of effectiveness.