Perisphincteric injection of botulinum toxin type A. A treatment option for patients with chronic prostatic pain?

Chronic prostatic pain is still a diagnostic and therapeutic problem. The clinical observation that prostatic and pelvic pain is accompanied by motoric and sensoric disorders of the pelvic floor muscles led to the hypothesis that prostatic pain roots in a changed processing of afferent and efferent information with the central nervous system (CNS).

Neuro-urological work-up of 11 male patients with chronic prostatic pain was completed. This included a clinical evaluation of pelvic floor function, urodynamic investigation of bladder and urethra function and a cystoscopy to exclude morphological aberrations. A transurethral perisphincteric injection of 200 units botulinum toxin type A (BTX) was followed by a 2- to 4-week visit to evaluate their influence on the neuro-urological symptomatology.

All chronic prostatic pain patients suffered from a pathological pelvic floor tenderness, an inability of sufficient conscious pelvic floor control, a urethral hypersensitivity/hyperalgesia and a urethral muscle hyperactivity. Basic parameters of bladder function (capacity, sensitivity, compliance) were normal. The BTX injection was followed by a pelvic floor muscle weakening and a relief of prostatic pain and urethral hypersensitivity/hyperalgesia. A botulinum-related decrease of the functional urethral length, the urethral sphincter closure pressure, the postvoid residual volume and an increase of the peak and average uroflow were objectivated.

A weakening of the urethral sphincter muscle via blocking acetylcholine release by BTX injection is followed by pain relief and symptom improvement. It can therefore be concluded that a barrage of nociceptive information from the dysfunctional pelvic floor overflood the CNS and induce a changed CNS processing. Interrupting the efferent branch of the disturbed central circle is one opportunity to treat chronic prostatic pain.