Non-invasive transcutaneous electrical stimulation in the treatment of overactive bladder

Slovak M, et al., Asian Journal of Urology (2015), 2, 92-101.
 Review provided by Cynthia Neville, PT, DPT, WCS for Pelvic Physiotherapy Journal Club May 4, 2016




Discussion of this article is open. Please post comments below.

 

 

Reason for choosing article: I strongly believe in NMES/TENS for pelvic floor rehab.

I use NMES on 80% of patients with PF dysfunctions, especially bladder control problems. I have had truly miraculous results with NMES on some patients (case report presented at CSM 2007). I met the author at ICS and was so excited that he was putting this info out to support clinical decision making.

·         Electrical stimulation (ES) has been used over several decades in the treatment of various lower urinary tract dysfunctions.

·         The S2-S4 nerve roots provide the principle motor supply to the bladder. Specifically the S3 root mainly innervates the detrusor muscle and is the main target of sacral neuromodulation.

·         Neuromodulation may be defined as affecting a nerve with stimulation or medication in order to directly impact the other nerves regulated by that nerve(?)

·         Posterior tibial nerve (PTN) is a mixed nerve containing L5-S3 fibers, originating again from the same spinal segments as the parasympathetic innervations to the bladder (S2-S4) is a well established sit for stimulation to the bladder

o   A commercial device (Urgent-PC, Uroplasty, Inc., Minnetonka, USA) uses PTNS over 12 sessions of the percutaneous posterior tibial nerve stimulation (PTNS), at weekly intervals. RCT showed significant improvement in overall OAB symptoms (60/110) compare to sham (23/110). It was shown that PTNS responders can continue to benefit from the therapy over 12 months.

Methods:

·         This review considers only non-invasive ES techniques, defined as “a procedure which does not involve introduction of an instrument into the body”; no needles, no intra-vaginal nor intra-anal electrodes; transcutaneous electrical nerve stimulation (TENS) was defined as a technique where the electrical stimuli are passed through the intact skin

·         Authors searched the electronic database PubMed from inception until December 2013. Search terms used were “urge incontinence”, “urgency”, “overactive bladder”, “urinary incontinence” or “detrusor instability” in combination with “electrical stimulation”, “TENS”, “transcutaneous electrical nerve stimulation”, “nerve stimulation”, “surface neuromodulation”, “non-invasive stimulation”, “trial” or “study”. In addition, we followed citations from the primary references to relevant articles which the database could not locate.

·         Exclusion criteria were: studies which were not in English; studies of fecal incontinence treatment; those involving children, those studying animal models; those involving percutaneous electrical stimulation, anal stimulation, vaginal/penile stimulation or implanted devices or those not primarily focused on storage symptoms. A flow diagram of the selection process is shown in Fig. 1.

·         The primary search identified 410 articles. Using the defined exclusion criteria authors reviewed in detail 16 articles; populations were widely heterogeneous

Sacral stimulation Electrode placement:

·         Peri-anal S2-S3 dermatomes 3 studies showed improvement = reduction in detrusor over activity, parameters varied: 12 h/day, 6 h/day,

·         Over sacral foramina , 2x/day x 15 min

Tibial Posterior Tibial Nerve Stimulation

·         Initially developed using the SANS (Stoller afferent nerve stimulator) 34 gauge needle electrode in SP6 acupuncture point and surface elect rode placed behind medial malellelus

·         Non-implanted electrodes are placed  the above medial malleolus and at medial aspect of calcaneus

·         Studies show promising results, 1 shows good acceptance of use of device at home

 

Suprapubic- study to reduce pain in PBS also showed decr urinary frequency, efficacy for use in OAB is unproven

Are the acute effects of stimulation of clinical significance? 

·         Researchers have tried to answer this by assessing the immediate effects of ES during a urodynamic study

·         A study on SCI patients receiving ES to thigh showed Increased maximum cystometry capacity MCC and decreased maximum detrusor pressure MDP, improved continence

·         A study on ES over S3 dermatome did not clearly demonstrated effects on MCC, but improved decrease in MDP

·         Studies in neurologic patients 50% improvement in MCC, other studies no sig difference

Which stimulation parameters?

·         The location of electrodes and range of stimulus parameters are likely to be critical factors in all forms of stimulation.

·         Relevant stimulus parameters include pulse width; pulse repetition frequency; burst length (if applicable) and stimulus intensity (preferably quoted as current as voltage stimulation coupled with uncertain electrode-tissue interface impedance leads to uncertainty as to delivered stimulus strength). The technical description of the stimuli used in some studies does not give all these details.

·         Stimulus intensity in question- below motor threshold? Above perception threshold? To anal wink?

Sham?

·         Sham ES is difficult to produce 2 to sensation

·         One method : Habituation as sham- tell the pt that they are getting used to stim then turn intensity to 0

·         One study did not tell participants that them may receive sham stim- ethical?

Conclusion: The current consensus is that the most promising site of stimulation is the S3 area of the spinal cord over the sacral region or over the posterior tibial nerve, but it is not clear which approach to stimulus delivery is the most effective. Little is known about the underlying mechanisms of action and which exact structures need to be stimulated.

Questions for discussion:

·         How often do you use TENS/NMES?

 

·         What parameters?

 

·         Do you issue units for home use?

 

·         What are barriers to using TENS?

 

·         What are best results?