Emil A. Tanagho

Neural Stimulation for Control of Voiding Dysfunction: A Preliminary Report in 22 Patients with Serious Neuropathic Voiding Disorders

Our experience with electrode implantation has demonstrated that the most successful combination to achieve continence and promote bladder evacuation is implantation on the ventral component of S3 or S4 and extensive dorsal rhizotomy with selective peripheral neurotomy. Of 22 patients with serious neuropathic voiding disorders treated during the last 6 years results were available for evaluation in 19 (2 were lost to followup and 1 was withdrawn from the protocol because of an infection at the receiver site). In 8 patients (42 per cent) complete success was achieved. These patients have regained reservoir function, are completely dry and void with electrical stimulation. The voiding is synchronous, with low voiding pressure and low residual urine volumes. Ten patients qualify as having partial success. They have regained reservoir function and are dry. One patient voids partially with stimulation, 5 depend on intermittent self-catheterization, 1 regained reservoir function and received an artificial sphincter, and 3 are catheter-dependent (these 3 all had been incontinent preoperatively despite continuous catheter drainage). The remaining patient entered the program long after a cerebrovascular accident and treatment has failed owing to poor selection. The stimulation parameters, once stabilized, did not need to be increased, and neither the surgical manipulation of the sacral roots nor the electrode implantation resulted in further neural loss in any patient.

Colpocystourethropexy: The Way we do it

In pure stress urinary incontinence the sphincteric mechanism is intact. Restoration of normal position and support to the vesicourethral segment usually re-establish normal sphincteric function. A suprapublic approach is used to gain adequate mobilization of the anteriorr vaginal wall and vesicourethral segment. Full thickness sutures applied in the anterior vaginal wall as far lateral from the urethra as possible are then tied to Coopers ligament. Forward and upward lifting of the vesicourethral segment is achieved but the urethra is free in a wide retropubic space. Normal position with limited mobility of the sphincteric segment is attained, yet compression or obstruction of the urethra and surgical trauma to the delicate sphincteric musculature are avoided. Adsorbable sutures are used. Permanent fixation is to be achieved by the postoperative fibrosis made possible after all retropubic fat has been cleared away. This technique has been uniformly successful in virginal cases and in the great majority of the least favorable cases, after repeated failures. Adequate mobilization proper placement of sutures and prevention of compression and surgical damage are the keys to longlasting successful repair.

Clinical Significance of Sacral and Pudendal Nerve Anatomy

The neuroanatomy and neurophysiology of the external urethral closure mechanisms still are under debate because the motor fibers that emanate from the sacral plexus and pudendal nerve to supply this segment have not been traced, nor has their functional interrelationship been established. Therefore, we dissected 3 male human cadavers (aged 31 to 69 years) by tracing the entire sacral plexus, particularly the pudendal nerve, from the cauda equina throughout the branching of the nerves to their final destination. The dissection demonstrated that the extrinsic urethral sphincter, formed by the rhabdosphincter around the membranous urethra as well as the levator ani muscle and pelvic floor (especially the transversus perinei muscle), is innervated by somatic nerve fibers that emanate primarily from sacral roots S2 and S3. In 5 patients with neurogenic lower urinary tract dysfunction electrostimulation of the sacral root and pudendal nerve markedly increased intraurethral closure pressures. Stimulation of the pudendal nerve or its transversus perinei branch alone resulted in an increase in intraurethral closure pressure to 60 to 70 cm. water--an increase similar to that produced by stimulation of the sacral root without neurotomy. By means of neurotomy and/or neural blockade with lidocaine we were able to differentiate between the contributions of each muscular element to the external sphincteric mechanism. Almost 70 per cent of the closure pressure of the external urethral sphincter is induced by stimulation of the S3 ventral root, while the other 30 per cent derives from S2 and S4 neuronal impulses.

Detailed anatomy of penile neurovascular structures: surgical significance.

In 10 formalin-preserved adult male cadavers, dissection of the penile veins, arteries and nerves revealed information of clinical importance. The main venous drainage of the corpora cavernosa is via the cavernous veins, with additional drainage through the circumflex, deep dorsal, and crural veins. The arterial supply of the cavernous bodies varied remarkably, and the incidence of an accessory internal pudendal artery was high. The cavernous nerves, previously believed to be microscopic structures, were in fact identifiable grossly, and we were able to follow them from the region of the hilum of the penis to the prostate. The nature of these nerves was then confirmed by serial histologic sectioning. This detailed knowledge of the venous drainage and arterial and nervous supply of the penis, as well as of the relationships among the cavernous structures in the hilum of the penis, can elucidate the cause of erectile dysfunction and provide a valuable guide for surgical correction of vasculogenic and neurogenic impotence.

Mechanisms of venous occlusion during canine penile erection: an anatomic demonstration

Hemodynamic studies have clearly demonstrated that intracorporeal injection of papaverine causes an increase of venous outflow resistance, and we therefore undertook a study of the venous drainage of the canine penis to delineate the anatomic changes in the venular structure during papaverine-induced erection. In 11 dogs, the corpora cavernosa were examined by corrosion casting in six and serial trichrome staining and histologic sectioning in five. Low-power scanning electron microscopy of the corrosion casts demonstrated the existence of a venular plexus interposed between the tunica albuginea and the sinusoidal spaces. After papaverine injection, this subalbugineal venular plexus is compressed between the dilated sinusoids from below and the tunica albuginea from above, such that venous drainage is effectively impeded. Examination of two cadaveric human penile corrosion casts by low-power scanning electron microscopy revealed evidence of a similar subalbugineal venular plexus draining into the emissary veins along the shaft of the penis. Based on the above, a model for the anatomic basis of venous occlusion during penile erection is outlined. Along with arteriolar and sinusoidal smooth-muscle relaxation, this can account for the three basic hemodynamic changes necessary for erection: increased arterial inflow, increased intracorporeal pressure, and increased venous outflow resistance.

Bladder pacemaker: Scientific basis and clinical future

Complete intermittent emptying of the denervated bladder is essential to maintain the integrity of the urinary tract. Intraspinal extradural segments of the sacral roots in the canine can be stimulated electrically to induce bladder emptying effectively, especially in conjunction with selective neurotomy to make the stimulus pure autonomic effect on the bladder wall itself. With varying parameters of stimulation, one also can induce sustained voluntary sphincter activity to maintain continence--which obviates the problem of skeletal muscle fatigue. Combination of the two--detrusor stimulation for emptying and sphincteric stimulation to achieve control--are the first steps toward utilization of an electronic bladder pacemaker in the presence of an intact reflex arc. Its use in humans will be possible in the near future.

IN VITRO FUNCTIONAL PROPERTIES OF THE RAT BLADDER REGENERATED BY THE BLADDER ACELLULAR MATRIX GRAFT

Abstract Purpose To assess the response of rat urinary bladder regenerated by the homologous bladder acellular matrix graft (BAMG) to in vitro electrical and pharmacologic stimuli. Materials and Methods In Sprague-Dawley rats, partial cystectomy (>50%) was performed, followed by BAMG augmentation cystoplasty. After 4 months, organ bath studies of tissue strips in 10 were used to compare the contractility of the BAMG regenerates and the corresponding host detrusor smooth muscle. Results The BAMG regenerates exhibited contractile activity to electrical field stimulation and a qualitatively identical pattern of response to muscarinic, purinergic, alpha- and beta-adrenergic drug administration and nitric oxide. At 4 months after surgery, the maximum forces of contraction of the BAMG regenerates to carbachol stimulation amounted to close to 80% of the host bladder response. With electrical field stimulation, they equaled 44% and 62% of the host bladder response after 2.5 and 4 months, respectively. Histological and immunohistochemical studies confirmed the presence of receptors for neurotransmitters that these functional in vitro studies implied. Conclusions The present study provides further evidence that augmentation cystoplasty with the BAMG leads to functional regeneration of the rat bladder detrusor smooth muscle.

Priapism: a refined approach to diagnosis and treatment.

The recent introduction of intracorporeal injections of papaverine and phentolamine for the diagnosis and treatment of impotence has resulted in an increased incidence of iatrogenic priapism. Based on our research into penile hemodynamics we propose a refined approach to all types of priapism. Intracorporeal blood gas and pressure monitoring should be used to differentiate ischemic (low flow) from nonischemic (high flow) types. Most cases of papaverine-induced or phentolamine-induced priapism will respond to aspiration alone or in combination with intracorporeal instillation of a diluted alpha-adrenergic agent. In spontaneous priapism alpha-adrenergic agents can be tried first if patients have only mild or no ischemia. In patients with severe ischemia stagnant blood should be evacuated and a shunt procedure should be performed to allow metabolic replenishment of tissue. Intracorporeal pressure monitoring will help to determine the size and number of shunts needed to re-establish corporeal circulation.

Interstitial cystitis : increased sympathetic innervation and related neuropeptide synthesis

To investigate the possibility of a neural deterioration of the bladder wall in interstitial cystitis, bladder tissue from 10 patients with interstitial cystitis was compared with that from 10 control subjects by means of immunohistochemistry. An enhanced innervation of the bladder in the submucosa and detrusor muscle was found to represent an increase of sympathetic but not cholinergic neurons. In interstitial cystitis the number of neurons positive for vasoactive intestinal polypeptide and neuropeptide Y was higher and carried a larger number of axonal varicosities, whereas the number of neurons positive for substance P and calcitonin-gene-related peptide was not significantly different in both groups. We conclude that interstitial cystitis is associated with increased sympathetic outflow into the bladder and altered metabolism of vasoactive intestinal polypeptide and neuropeptide Y. Since similar changes have been observed in other inflammatory diseases of a presumably autoimmune nature, such as rheumatoid arthritis, Crohns disease and colitis ulcerosa, the pathophysiology of interstitial cystitis may share common pathways with the latter. Experience in these diseases may facilitate a better understanding of the pathophysiology of interstitial cystitis and suggest new therapeutic concepts.

Functional Evaluation of Penile Veins by cavernosography in Papaverine-Induced Erection

Of 49 patients in whom cavernosography was performed after papaverine-induced erection 38 had abnormal venous leakage to various drainage systems (corpus spongiosum, cavernous vein or superficial and deep dorsal veins). Because the effect of papaverine on penile arteries, sinusoids and veins is similar to that caused by electrostimulation, we believe that this technique is better than other reported means of evaluating the functional status of the penile veins. However, we recommend that only patients with a normal arterial response but poor erection after papaverine injection be considered candidates for erection cavernosography, since they most likely will benefit.