Screening Tests for Evaluation of Potential Efficacy of Chronic Neurostimulation as a Therapy for Pelvic Floor Dysfunction
Publication Date: 2003-Oct-01
The IP.com Prior Art Database
Todd K. Whitehurst: INVENTOR [+5]
Methods for evaluating whether a patient with pelvic floor dysfunction(s) is suited to therapy via chronic neuromodulation (e.g., with a system control unit and lead(s)/catheter(s) or microstimulator(s)) are disclosed. Based on the results of these acute or subacute (i.e., less than or equal to 31 day) Screening Tests, patients may be accepted or rejected for chronic neuromodulation to treat pelvic floor dysfunction, such as urinary urgency, frequency, urge incontinence, stress incontinence, fecal incontinence, and pelvic pain.
Background and Summary
Pelvic floor dysfunction can be classified into several broad categories such as incontinence, sexual dysfunction, and pelvic pain. Incontinence can be further divided into urge incontinence, stress incontinence, urinary urgency frequency syndrome, fecal incontinence, overflow incontinence, to name a few. Sexual dysfunctions arising from pelvic floor problems include dyspareunia, erectile dysfunction, lack of orgasm or pain during orgasm. Pelvic pain syndromes may be the most complex of all including interstitial cystitis, vulvodynia, dyspareunia, coccygodynia, anismus, and chronic prostatitis, where one syndrome can cascade into several.
Though the etiology of these problems often times is clearly of neurologic origin (spinal cord injury, Parkinson’s disease, amyotrophic lateral sclerosis, multiple sclerosis, stroke, etc.), the root cause in many patients can remain unknown. Fortunately, traditional conservative treatments that include pelvic floor exercises, pelvic floor myofascial trigger point manual therapy, biofeedback, as well as pharmacological appear to be effective in the majority of cases. In cases where conservative treatments fail, patients are faced with few surgical options including bladder augmentation and sacral nerve neuromodulation. Both of these options are fraught with significant side effects.
Most patients are initially treated conservatively with bladder retraining, pelvic floor exercises and biofeedback. This regimen is often supplemented with drugs. However, about 40% of patients with these forms of lower urinary tract dysfunction do not experience acceptable relief with these forms of treatment, and thus remain a therapeutic problem.
A chronic implantable sacral nerve root neurostimulator is commercially available for the treatment of urge incontinence, which allows women with severe and/or medically refractory urge incontinence to gain significant control over their incontinence symptoms. This sacral nerve stimulation (SNS) system (Medtronic InterStim®) produces electrical pulses with a battery-operated generator that is implanted in the abdomen. A wire connected to it runs to the sacral nerves in the lower back.
The mechanism of action of neuromodulation for incontinence is still unclear, but it is hypothesized that the neurostimulation modulates reflex pathways involved in the filling and evacuation phase of the micturition cycle. Stimulation of large myelinated fibers of the sacral roots S3 and S4 decreases the spastic behavior of the pelvic floor and enhances the tone of the urethral sphincter. In many subjects, the primary voiding dysfunction appears to begin with unstable urethral activity, which activates the voiding reflexes, leading to detrusor instability and the associated urgency/frequency syndrome and incontinence. The inhibitory effect of the enhanced ur...