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Neurologic Sequelae of Abdominoperineal Resection
Symposium on Urologic Surgery
Neurologic Sequelae of Abdominoperineal Resection Leonard D. Gaum, M.D., F.R.C.S. (C)*
Abdominoperineal resection as popularized by Miles 32 in 1908 is a standard treatment for rectal disease. A significant number of patients undergoing this operation will develop postoperative vesicourethral dysfunction. The reported rate of this complication has varied considerably from 7 to 68 per cent, 3 • 5 • 11· 15• 17• 18• 20 • 21 • 23 • 24 • 35• 40-42 with the average reported incidence around 30 per cent. Although angulation of the bladder neck and latent prostatic obstruction may contribute in part to postoperative urinary retention, urodynamic evaluation has revealed a neurologic injury as the main cause of the disturbance in micturition. 17• 18• 20 • 23 • 30• 35· 42 Failure to recognize the primary neurologic nature of the postoperative urinary difficulty may lead to these patients being subjected to unnecessary, repeated prostatectomy, which may not alleviate the problem of retention and may, in fact, lead to urinary incontinence. 15· 21 • 27• 29· 30 Similarly, autonomic nerve injury at the time of surgery can result in sexual dysfunction ranging from a partial disturbance of erection to complete impotence. The reported incidence of such disorders is about 20 per cent following abdominoperineal resection for benign disease and is much higher with malignant disease, 33 to 100 per cent. 3 • 9 • 15• 22 • 28 • 39• 42 · 43 • 46 This is a serious complication, particularly in younger patients. A clear understanding of the neuroanatomy and neurophysiology involved in micturition and sexual function can help the surgeon to minimize these distressing complications.
NEUROANATOMY AND NEUROPHYSIOLOGY Micturition Normal vesicourethral function requires intact sensory and motor neural pathways. The smooth musculature of the detrusor and urethra receives autonomic sympathetic and parasympathetic innervation, whereas the striated external urethral sphincter is provided with somatic innervation (Fig. 1). *Assistant Professor of Urology, Washington University School of Medicine, St. Louis, Missouri
Surgical Clinics of North America-Yo!. 62, No. 6, December 1982
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pudendal n. lnf. hypogastric plexus Figure 1.
This schematic drawing shows the pelvic autonomic nerves.
Sympathetic pathways are complex and involve the thoracolumbar outflow of the sympathetic trunk (Tl2-L3) to the superior hypogastric plexus, the hypogastric nerves, and the inferior hypogastric plexus. The superior hypogastric plexus is found inferior to the aortic bifurcation and overlies the fifth lumbar vertebra. It is composed of sympathetic preganglionic, postganglionic and visceral afferent nerve fibers. Below the sacral promontory, the superior hypogastric plexus forms paired hypogastric nerves containing sympathetic preganglionic and postganglionic fibers as well as visceral afferent fibers. The nerve lies between the peritoneum and endopelvic fascia and medial to the common iliac vessels and the ureter. On the left, the hypogastric nerve may course posterior to the superior hemorrhoidal vessels. The inferior hypogastric plexus-composed of preganglionic and postganglionic sympathetic fibers, preganglionic fibers of the sacral parasympathetic outflow, and visceral afferent fibers-is situated anterolateral to the rectal ampulla. In the female, it is lateral to the uterine cervix, which may offer some protection from a surgical injury. 35 These sympathetic nerve fibers ultimately end in ganglia located in the wall of the bladder neck and prostate, seminal vesicles, and the ampulla of the vas. The striated external urethral sphincter is innervated by the internal
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pudendal nerves arising from ventral sacral cord roots S2-S4. Innervation is also provided to the external anal sphincter and perineal skin, the labia and clitoris of the female, and the scrotum, penis, and ischiocavernosus and bulbocavernosus muscles of the male. On leaving the sacral foramina, the nerves pass through the sacrosciatic notch and reach the pelvic musculature by way of the ischiorectal fossa. Parasympathetic activity results in a detrusor contraction, whereas sympathetic activity results in tonic closure of the smooth musculature of the internal sphincter directly and indirectly depresses parasympathetic activity of the detrusor, thus facilitating urine storage. With micturition, there is a parasympathetic-induced contraction of the detrusor, a reflex decrease of sympathetic stimulation with resultant smooth muscle relaxation, 12• 13 and an inhibition of somatic activity of the striated pelvic floor musculature.
Sexual Function Male sexual function involves the coordinated processes of erection, emission, ejaculation, and detumescence and is dependent on an intact autonomic nervous system. A number of clinical observations support this fact. Ganglion-blocking agents such as guanethidine deplete norepinephrine at peripheral nerve endings, resulting in sympathetic neuronal blockade and loss of potency or ejaculation. 36 Erectile impotence is the presenting symptom in about 10 per cent of diabetic males, with isolated retrograde ejaculation occurring as a sequela of diabetic neuropathy. 1 In 1951 Whitelaw and Smithwick described the loss of ejaculation secondary to lumbar sympathectomy. 45 Further evidence is provided by reports of the loss of ejaculation and impotence after abdominoperineal procedures. 8• 9 Erection is a vascular phenomenon resulting from engorgement of the vascular spaces in the corpora cavernosa and the corpus spongiosum. Until recently, the most widely accepted explanation for penile erection was the polster theory of Conti. 10 According to this theory, there are physiologic valves or polsters located between the arterioles and the vascular spaces in the corpora. With the contraction of the smooth muscle of these valves, blood is shunted away from the vascular lacunae of the corpora into the veins, and the penis is flaccid. When the smooth muscle of the polsters relaxes, the vascular lacunae of the cavetnosus bodies distend and erection occurs. Whether active constriction of the deep efferent veins is necessary as well remains unclear. Recent evidence challenges the existence and function of polsters in the vascular mechanisms of erection. 6• 7 Histochemical studies have shown the presence of catecholamine nerve fibers in the corpus cavernosum and alpha and beta adrenergic receptors in the cavernous tissue. 14 The presence of vipergic nerves, a newly recognized class of autonomic nerves, and vasoactive polypeptides in the male genital tract suggests that the activity of the vipergic nerves may be important in the nervous control of male external genitalia. 33 There are two neural pathways involved (Fig. 2). With local tactile stimulation, reflexogenic erections occur and are mediated by afferent fibers in the pudendal nerves and efferent fibers in the S2-S4 parasympathetic outflow or nervi erigentes. Psychogenic erections occur via the thoracolumbar sympathetic outflow and the sacral parasympathetic fibers. The final common pathway for vasomotor control of
1078
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Psychic Stimulation Cortex
Tactile Stimulation Glans
Lumbar Center
Parasympathetic Sacral Outflow
Sympathetic lnhi bit ion
l""''"'" En"""'"""'
!
Penile Erection
Detumescence Figure 2.
Mechanisms of erection are shown.
the penile vasculature appears to be sympathetically mediated by short adrenergic neurons 14 • Emission is the first stage of ejaculation (Fig. 3). During emission the smooth musculature of the epididymis, vasa deferentia, seminal vesicles, and prostatic capsule contracts with delivery of sperm and glandular secretions into the posterior urethra. These events are' mediated primarily through the sympathetic nervous system. During ejaculation proper, there is antegrade transport of seminal fluid from the posterior urethra through the external urethral meatus. Sympathetic stimulation results in closure of the bladder neck, preventing retrograde ejaculation, while parasympathetic activity produces rhythmic contraction of the striated ischiocavernosus and Tactile Stimulation Glans
Psychic Stimulation Cortex
Orgasm
I
Lumbar Center
Sympathetic Motor (lj 2-L~ Smooth Muscle Contraction of Prostate, Seminal Vesicles ,Vas Deferens
1
Parasympathetic Motor ( S 2 - S4 ) Striated Muscle Contraction of Perineum
1
Bladder Neck Closure Seminal Emission Figure 3.
Projectile Ejaculation
Mechanisms of ejaculation are shown.
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bulbocavernosus muscles with compression of the bulbous urethra and expulsion of semen. This occurs at the time of orgasm. Following ejaculation, the arterial smooth musculature is constricted under sympathetic influence. Blood is expelled from the cavernous bodies and detumescence occurs.
AREAS OF MISADVENTURE AND SEQUELAE From Miles' original description of the operative procedure and observations in the operating room and anatomy laboratory, 2• 28 • 32• 44 • 46 the autonomic pathways are most likely to be interrupted at the sacral promontory or during their course about the rectum. The superior hypogastric plexus (sympathetic) is in close association with the pre-aortic lymphatics, and therl:)fore it is sometimes deliberately removed in the course of an en bloc pre-aortic node dissection for colon or rectal carcinoma. Isolated sympathetic nerve injury results in retrograde ejaculation or loss of seminal emission. Although retrograde ejaculation is potentially reversible with alpha-adrenergic agents, loss of seminal emission is not treatable. With hypogastric lymph node dissection or extensive dissection beyond the confines of the endopelvic fascia, the hypogastric nerve and inferior hypogastric plexus (sympathetic and parasympathetic) can be injured, with resulting erectile and detrusor dysfunction. Pudendal nerve injury (somatic) occurs in the presacral space and ischiorectal fossa and may affect ejaculation or urinary continence.
PREOPERATIVE EVALUATION Because of the high incidence of postoperative vesicourethral and sexual dysfunction, a preoperative urologic evaluation is desirable in most cases. A detailed history and physical examination will help to document the patient's voiding pattern, the force and caliber of the stream, pertinent past urologic history, and the size of the prostate. Although this aids the physician in anticipating postoperative voiding dysfunction, it is not predictive of those patients who are likely to develop postoperative complications requiring prostatectomy. 21 • 40 Reports vary as to the stage ofthe rectal malignant disease and subsequent vesicourethral dysfunction. Fowler18 found an increased incidence of denervation in those patients with invasive tumors, a finding at variance with that of Tank. 40 To minimize urologic complications, a preoperative intravenous urogram with voiding and postvoiding films is advised. 24• 40 This serves to define unrecognized congenital abnormalities, delineate obstruction or invasion of the ureters and bladder by the primary lesion, and provide information on evacuation efficiency as evidenced by residual urine on voiding and postvoiding films. The incidence of abnormal preoperative urograms was 30 per cent in some series; 4 • 24• 34 however, of these abnormalities, 25 per cent were anatomic variations and 75 per cent were nonsignificant urologic diseases.
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None of the postoperative urologic complications was related to the radiologic findings. The history or radiologic findings may indicate the need for endoscopic or urodynamic evaluation. Cystourethroscopy will define structural abnormalities, establish the presence or absence of outlet obstruction, and rule out extension of malignant disease. Urodynamic evaluation is helpful in determining unsuspected neurologic abnormalities and supplements an overall view of vesicourethral function.
URODYNAMIC FINDINGS Vesicourethral dysfunction after abdominoperineal resection should be evaluated urodynamically. Most series document cystometric findings of a parasympathetic nerve injury with resulting sensory and motor abnormalities of detrusor function. 17• 20• 23 • 31 • 35• 42 Although cystometry is useful for determining the presence or absence of a detrusor reflex, 26 it alone does not provide a complete picture of vesicourethral function. The dynamic interaction between the pathologic detrusor and the urethral sphincter mechanism must be determined in the patient with detrusor hypofunction in order to institute appropriate therapy. McGuire has shown that isolated or combined dysfunction of the smooth and striated muscles of the sphincter mechanism can occur after abdominoperineal resection. 30 This is significant when spontaneous voiding does not occur and prostatic hypertrophy is considered the cause of the dysfunction. Prostatectomy in the presence of sphincter dysfunction may not relieve the problem and may result in incontinence. U rodynamic evaluation with fluoroscopic control can most accurately define detrusor-urethral coordination and the level of urinary continence. In the presence of a detrusor contraction and relaxation of the striated external sphincter, persistent closure of the prostatic urethra is diagnostic of prostatic obstruction and prostatectomy is indicated. If continence occurs at the striated external sphincter and the proximal urethra is patulous, pudendal nerve function is intact and prostatectomy is not likely to be helpful. If continence is maintained at the neck of the bladder, the internal sphincter is intact, but the striated external sphincter may or may not be functional. Striated external sphincter activity can be assessed by fluoroscopy, electromyography, or urethral pressure profilometry. With impairment of striated muscle function, a prostatectomy will result in incontinence. With complete smooth and striated muscle dysfunction, the patient is totally incontinent in the upright position. When prostatic obstruction is not a consideration, detrusor areflexia may exist with coordinated sphincter activity. This condition has been successfully managed by cholinergic stimulation with bethanechol chloride. 26 With a nonrelaxing internal sphincter, bethanechol with phenoxybenzamine has been useful. 25 The striated external urethral sphincter in patients with neurogenically mediated detrusor areflexia may not relax appropriately with attempts at voiding. Intermittent catheterization can be employed, as external sphincterotomy can result in severe incontinence.
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SEXUAL DYSFUNCTION Although sexual dysfunction is common after abdominoperineal resection, the exact incidence is difficult to determine for several reasons. The age of the patient and the extent of disease are important factors. 3 • 22 • 39 • 46 Stahlgren found less alteration in sexual function in patients in the sexually active years who were operated upon for benign disease. 39 Aso reported that sexual disturbances were more common in patients over 60 years of age and in those undergoing more formidable surgical procedures. 3 However, patients having rectal excision for malignant disease are usually much older than those having proctocolectomy for benign conditions. With improvement in their general health, many chronically ill patients will have improved sexual function. In some patients, the presence of a stoma and appliance will adversely affect sexual function. Sexual potency involves the psychic desire for sexual intercourse together with normal erection, ejaculation, and orgasm. Of the four factors involved in this process, ejaculation and erection are most often affected and orgasm and desire the least. 3 • 9 If only retrograde ejaculation occurs, it is potentially reversible with alpha-adrenergic agents, but there is no treatment for loss of seminal emission and transport. Erectile dysfunction can be successfully treated with various penile prostheses. 16• 19 • 37• 38 This risk of sexual dysfunction and therapeutic modalities should be discussed with each patient preoperatively.
SUMMARY Abdominoperineal resection is a procedure with significant morbidity. Knowledge of the neuroanatomy can help the surgeon to avoid or minimize the sequelae of neural injury.
REFERENCES 1. Amelar, R.D.: Infertility in the male. In Lewis, D. D. (ed.): Practice of Surgery. Vol. 2, Urology. Hagerstown, Maryland, Harper and Row, 1971. 2. Ashley, F., and Anson, B.: The pelvic autonomic nerves in the male. Surg. Gynecol. Obstet., 82:598, 1946. 3. Aso, R., and Yasutomi, M.: Urinary and sexual disturbances following radical surgery for rectal cancer, and pudendal nerve block as a countermeasure for urinary disturbance. Amer. J. Proctol., 25:60, 1974. 4. Barbaric, Z. L., Wolfe, D. E., and Segal, A. J.: Urinary tract after abdominoperineal resection. Radiology, 128:345, 1978. 5. Bartizal, J,, and Slosberg, P. A.: Combined abdominoperineal resection. SuRG. CLJN. NORTH AM., 57:1253, 1977. 6. Benson, G. S.: Mechanisms of penile erection. Invest. Urol., 19:65, 1981. 7. Benson, G. S., McConnell, J. A., and Schmidt, W. A.: Penile "polsters:" Functional structures or atherosclerotic changes? J. Urol., 125:800, 1981. 8. Bernstein, W. C., and Bernstein, E. F.: Sexual dysfunction following radical surgery for cancer of the rectum. Dis. Col. Rectum, 9:328, 1966. 9. Bors, E., and Comarr, A. E.: Neurological disturbances of sexual function with special reference to 529 patients with spinal cord injury. Urol. Survey, 10:191, 1960. 10. Conti, G.: L' erection du penis humain et ses bases morphologico-vasculaires. Acta Anat. (Basel), 14:217, 1952.
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11. Cook, E. N., Ten Cate, H. W., and Potter, W. M.: Urinary retention following operations on the bowel. J. Urol., 89:255, 1963. 12. DeGroat, W. C.: Nervous control of the urinary bladder of the cat. Brain Res., 87:201, 1975. 13. DeGroat, W. C., and Theobald, R. J.: Reflex activation of sympathetic pathways to vesical smooth muscle and parasympathetic ganglia by electrical stimulation of vesical afferent. J. Physiol. (Lond.), 259:223, 1976. 14. Domer, F. R., Wessler, G., Brown, R. L., eta!.: Involvement of the sympathetic nervous system in the urinary bladder internal sphincter and in penile erection in the anesthetized cat. Invest. Urol., 15:404, 1978. 15. Eickenberg, H. U., Amin, M., Klompus, W., eta!.: Urologic complications following abdominoperineal resection. J. Urol., 115:180, 1976. 16. Finney, R. P.: New hinged silicone penile implant. J. Urol., 118:585, 1977. 17. Fowler, J. W.: Bladder function following abdominoperineal excision of the rectum for carcinoma. Brit. J. Surg., 60:574, 1973. 18. Fowler, J. W., Bremner, D. N., and Moffat, L. E. F.: The incidence and consequences of damage to the parasympathetic nerve supply to the bladder after abdominoperineal resection of the rectum for carcinoma. Brit. J. U rol., 50:95, 1978. 19. Furlow, W. L.: Surgical management of impotence using inflatable penile prosthesis. Experience with 36 patients. Mayo Clin. Proc., 51:325, 1976. 20. Gerstenberg, T. C., Nielson, M. L., Clausen, S., eta!.: Bladder function after abdominoperineal resection of the rectum for anorectal cancer. Ann. Surg., 191:81, 1980. 21. Glass, R. L., and Spratt, J. S.: Urinary complications after abdominoperineal resection of the rectum in men. Am. Surgeon, 34:238, 1968. 22. Goligher, J.: Surgery of the Anus, Rectum and Colon, 3rd ed. London, Bailliere Tindall, 1975. 23. Kontturi, M., Larmi, T. K. I., and Tuononen, S.: Bladder dysfunction and its manifestations following abdominoperineal extirpation of the rectum. Ann. Surg., 179:179, 1974. 24. Kramhoft, J., Kronberg, 0., Backer, 0. G., eta!.: Urologic complications after operations for anorectal cancer, with an evaluation of pre-operative intravenous pyelography. Dis. Col. Rectum, 18:118, 1975. 25. Krane, R. J., and Olsson, C. A.: Phenoxybenzamine in neurogenic bladder dysfunction. II. Clinical considerations. J. Urol., 110:653, 1973. 26. Lapides, J., Friend, C. R., Ajemian, E. P., eta!.: Denervation supersensitivity as a test for neurogenic bladder. Surg. Gynecol. Obstet., 114:241, 1962 27. Leadbetter, G. W., and Leadbetter, W. F.: A new approach to the problem of urinary retention following abdominoperineal resection for carcinoma of the rectum. Surg. Gynecol. Obstet., 107:333, 1958. 28. Lee, J. F., Maurer, V. M., and Block, G. E.: Anatomic relations of pelvic autonomic nerves to pelvic operations. Arch. Surg., 107:324, 1973. 29. McGuire, E. J.: Urodynamic evaluation after abdominal-perineal resection and lumbar intervertebral disk herniation. Urology, 6:63, 1975. 30. McGuire, E. J.: Neurovesical dysfunction after abdominoperineal resection. SURG. CLIN. NORTH AM., 60:1207, 1980. 31. Marshall, V. F., Pollack, R. S., and Miller, C.: Observations on urinary dysfunction after excision of the rectum. J. U rol., 55:409, 1946. 32. Miles, W. E.: A method of performing abdominoperineal excision for carcinoma of the rectum and of the terminal portion of the pelvic colon. Lancet, 2:1812, 1908. 33. Polak, J. M., Mina, S., Gu, J., eta!.: Vipergic nerves in the penis. Lancet, 2:217, 1981. 34. Prager, E., Swinton, N. W., Corman, M. L., eta!.: Intravenous pyelography in colorectal surgery. Dis Col. Rectum, 16:479, 1973. 35. Rankin, J. T.: Urological complications of rectal surgery. Brit. J. Urol., 41:655, 1969. 36. Schirger, A., and Gifford, R. W.: Guanethidine, a new antihypertensive agent: Experience in the treatment of 36 patients with severe hypertension. Proc. Mayo Clin., 37:100, 1962. 37. Scott, F. B., Bradley, W. E., and Timm, G.: Management of erectile impotence. Use of implantable inflatable prosthesis. Urology, 2:80, 1973. 38. Small, M. D., and Carrion, H. M.: A new penile prosthesis for treating impotence. Con temp. Surg., 7:29, 1975. I
I,
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39. Stahlgren, L. H., and Ferguson, L. K.: Influence on sexual function of abdominoperineal resection for ulcerative colitis. New Engl. J. Med., 259:873, 1958. 40. Tank, E. S., Ernst, C. B., Woolson, S. T., eta!.: Urinary tract complications of anorectal surgery. Am. J. Surg., 123:118, 1972. 41. Ward, J. N., and Nay, H. R.: Immediate and delayed urologic complications associated with abdominoperineal resection. Am. J. Surg., 123:642, 1972. 42. Watson, P. C., and Williams, D. I.: The urological complications of exicision of the rectum. Brit. J. Surg., 40:19, 1952. 43. Weinstein, M., and Roberts, M.: Sexual potency following surgery for rectal carcinoma: A following-up of 44 patients. Ann. Surg., 185:295, 1977. 44. Weiss, H. D.: The physiology of human penile erection. Ann. Intern. Med., 76:793, 1972. 45. Whitelaw, G. P., and Smithwick, R. H.: Some secondary effects of sympathectomy with particular reference to disturbance of sexual function. New Engl. J. Med., 245:121, 1951. 46. Yeager, E. S., and Van Heerden, J. A.: Sexual dysfunction following proctocolectomy and abdominoperineal resection. Ann. Surg., 191:169, 1980. Division of Urology Department of Surgery Washington University Medical Center 4960 Audubon Avenue St. Louis, Missouri 63110
Neurologic Sequelae of Abdominoperineal Resection Leonard D. Gaum, M.D., F.R.C.S. (C)*
Abdominoperineal resection as popularized by Miles 32 in 1908 is a standard treatment for rectal disease. A significant number of patients undergoing this operation will develop postoperative vesicourethral dysfunction. The reported rate of this complication has varied considerably from 7 to 68 per cent, 3 • 5 • 11· 15• 17• 18• 20 • 21 • 23 • 24 • 35• 40-42 with the average reported incidence around 30 per cent. Although angulation of the bladder neck and latent prostatic obstruction may contribute in part to postoperative urinary retention, urodynamic evaluation has revealed a neurologic injury as the main cause of the disturbance in micturition. 17• 18• 20 • 23 • 30• 35· 42 Failure to recognize the primary neurologic nature of the postoperative urinary difficulty may lead to these patients being subjected to unnecessary, repeated prostatectomy, which may not alleviate the problem of retention and may, in fact, lead to urinary incontinence. 15· 21 • 27• 29· 30 Similarly, autonomic nerve injury at the time of surgery can result in sexual dysfunction ranging from a partial disturbance of erection to complete impotence. The reported incidence of such disorders is about 20 per cent following abdominoperineal resection for benign disease and is much higher with malignant disease, 33 to 100 per cent. 3 • 9 • 15• 22 • 28 • 39• 42 · 43 • 46 This is a serious complication, particularly in younger patients. A clear understanding of the neuroanatomy and neurophysiology involved in micturition and sexual function can help the surgeon to minimize these distressing complications.
NEUROANATOMY AND NEUROPHYSIOLOGY Micturition Normal vesicourethral function requires intact sensory and motor neural pathways. The smooth musculature of the detrusor and urethra receives autonomic sympathetic and parasympathetic innervation, whereas the striated external urethral sphincter is provided with somatic innervation (Fig. 1). *Assistant Professor of Urology, Washington University School of Medicine, St. Louis, Missouri
Surgical Clinics of North America-Yo!. 62, No. 6, December 1982
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pudendal n. lnf. hypogastric plexus Figure 1.
This schematic drawing shows the pelvic autonomic nerves.
Sympathetic pathways are complex and involve the thoracolumbar outflow of the sympathetic trunk (Tl2-L3) to the superior hypogastric plexus, the hypogastric nerves, and the inferior hypogastric plexus. The superior hypogastric plexus is found inferior to the aortic bifurcation and overlies the fifth lumbar vertebra. It is composed of sympathetic preganglionic, postganglionic and visceral afferent nerve fibers. Below the sacral promontory, the superior hypogastric plexus forms paired hypogastric nerves containing sympathetic preganglionic and postganglionic fibers as well as visceral afferent fibers. The nerve lies between the peritoneum and endopelvic fascia and medial to the common iliac vessels and the ureter. On the left, the hypogastric nerve may course posterior to the superior hemorrhoidal vessels. The inferior hypogastric plexus-composed of preganglionic and postganglionic sympathetic fibers, preganglionic fibers of the sacral parasympathetic outflow, and visceral afferent fibers-is situated anterolateral to the rectal ampulla. In the female, it is lateral to the uterine cervix, which may offer some protection from a surgical injury. 35 These sympathetic nerve fibers ultimately end in ganglia located in the wall of the bladder neck and prostate, seminal vesicles, and the ampulla of the vas. The striated external urethral sphincter is innervated by the internal
NEUROLOGIC SEQUELAE OF ABDOMINOPERINEAL RESECTION
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pudendal nerves arising from ventral sacral cord roots S2-S4. Innervation is also provided to the external anal sphincter and perineal skin, the labia and clitoris of the female, and the scrotum, penis, and ischiocavernosus and bulbocavernosus muscles of the male. On leaving the sacral foramina, the nerves pass through the sacrosciatic notch and reach the pelvic musculature by way of the ischiorectal fossa. Parasympathetic activity results in a detrusor contraction, whereas sympathetic activity results in tonic closure of the smooth musculature of the internal sphincter directly and indirectly depresses parasympathetic activity of the detrusor, thus facilitating urine storage. With micturition, there is a parasympathetic-induced contraction of the detrusor, a reflex decrease of sympathetic stimulation with resultant smooth muscle relaxation, 12• 13 and an inhibition of somatic activity of the striated pelvic floor musculature.
Sexual Function Male sexual function involves the coordinated processes of erection, emission, ejaculation, and detumescence and is dependent on an intact autonomic nervous system. A number of clinical observations support this fact. Ganglion-blocking agents such as guanethidine deplete norepinephrine at peripheral nerve endings, resulting in sympathetic neuronal blockade and loss of potency or ejaculation. 36 Erectile impotence is the presenting symptom in about 10 per cent of diabetic males, with isolated retrograde ejaculation occurring as a sequela of diabetic neuropathy. 1 In 1951 Whitelaw and Smithwick described the loss of ejaculation secondary to lumbar sympathectomy. 45 Further evidence is provided by reports of the loss of ejaculation and impotence after abdominoperineal procedures. 8• 9 Erection is a vascular phenomenon resulting from engorgement of the vascular spaces in the corpora cavernosa and the corpus spongiosum. Until recently, the most widely accepted explanation for penile erection was the polster theory of Conti. 10 According to this theory, there are physiologic valves or polsters located between the arterioles and the vascular spaces in the corpora. With the contraction of the smooth muscle of these valves, blood is shunted away from the vascular lacunae of the corpora into the veins, and the penis is flaccid. When the smooth muscle of the polsters relaxes, the vascular lacunae of the cavetnosus bodies distend and erection occurs. Whether active constriction of the deep efferent veins is necessary as well remains unclear. Recent evidence challenges the existence and function of polsters in the vascular mechanisms of erection. 6• 7 Histochemical studies have shown the presence of catecholamine nerve fibers in the corpus cavernosum and alpha and beta adrenergic receptors in the cavernous tissue. 14 The presence of vipergic nerves, a newly recognized class of autonomic nerves, and vasoactive polypeptides in the male genital tract suggests that the activity of the vipergic nerves may be important in the nervous control of male external genitalia. 33 There are two neural pathways involved (Fig. 2). With local tactile stimulation, reflexogenic erections occur and are mediated by afferent fibers in the pudendal nerves and efferent fibers in the S2-S4 parasympathetic outflow or nervi erigentes. Psychogenic erections occur via the thoracolumbar sympathetic outflow and the sacral parasympathetic fibers. The final common pathway for vasomotor control of
1078
LEONARD
D.
GAUM
Psychic Stimulation Cortex
Tactile Stimulation Glans
Lumbar Center
Parasympathetic Sacral Outflow
Sympathetic lnhi bit ion
l""''"'" En"""'"""'
!
Penile Erection
Detumescence Figure 2.
Mechanisms of erection are shown.
the penile vasculature appears to be sympathetically mediated by short adrenergic neurons 14 • Emission is the first stage of ejaculation (Fig. 3). During emission the smooth musculature of the epididymis, vasa deferentia, seminal vesicles, and prostatic capsule contracts with delivery of sperm and glandular secretions into the posterior urethra. These events are' mediated primarily through the sympathetic nervous system. During ejaculation proper, there is antegrade transport of seminal fluid from the posterior urethra through the external urethral meatus. Sympathetic stimulation results in closure of the bladder neck, preventing retrograde ejaculation, while parasympathetic activity produces rhythmic contraction of the striated ischiocavernosus and Tactile Stimulation Glans
Psychic Stimulation Cortex
Orgasm
I
Lumbar Center
Sympathetic Motor (lj 2-L~ Smooth Muscle Contraction of Prostate, Seminal Vesicles ,Vas Deferens
1
Parasympathetic Motor ( S 2 - S4 ) Striated Muscle Contraction of Perineum
1
Bladder Neck Closure Seminal Emission Figure 3.
Projectile Ejaculation
Mechanisms of ejaculation are shown.
NEUROLOGIC SEQUELAE OF ABDOMINOPERINEAL RESECTION
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bulbocavernosus muscles with compression of the bulbous urethra and expulsion of semen. This occurs at the time of orgasm. Following ejaculation, the arterial smooth musculature is constricted under sympathetic influence. Blood is expelled from the cavernous bodies and detumescence occurs.
AREAS OF MISADVENTURE AND SEQUELAE From Miles' original description of the operative procedure and observations in the operating room and anatomy laboratory, 2• 28 • 32• 44 • 46 the autonomic pathways are most likely to be interrupted at the sacral promontory or during their course about the rectum. The superior hypogastric plexus (sympathetic) is in close association with the pre-aortic lymphatics, and therl:)fore it is sometimes deliberately removed in the course of an en bloc pre-aortic node dissection for colon or rectal carcinoma. Isolated sympathetic nerve injury results in retrograde ejaculation or loss of seminal emission. Although retrograde ejaculation is potentially reversible with alpha-adrenergic agents, loss of seminal emission is not treatable. With hypogastric lymph node dissection or extensive dissection beyond the confines of the endopelvic fascia, the hypogastric nerve and inferior hypogastric plexus (sympathetic and parasympathetic) can be injured, with resulting erectile and detrusor dysfunction. Pudendal nerve injury (somatic) occurs in the presacral space and ischiorectal fossa and may affect ejaculation or urinary continence.
PREOPERATIVE EVALUATION Because of the high incidence of postoperative vesicourethral and sexual dysfunction, a preoperative urologic evaluation is desirable in most cases. A detailed history and physical examination will help to document the patient's voiding pattern, the force and caliber of the stream, pertinent past urologic history, and the size of the prostate. Although this aids the physician in anticipating postoperative voiding dysfunction, it is not predictive of those patients who are likely to develop postoperative complications requiring prostatectomy. 21 • 40 Reports vary as to the stage ofthe rectal malignant disease and subsequent vesicourethral dysfunction. Fowler18 found an increased incidence of denervation in those patients with invasive tumors, a finding at variance with that of Tank. 40 To minimize urologic complications, a preoperative intravenous urogram with voiding and postvoiding films is advised. 24• 40 This serves to define unrecognized congenital abnormalities, delineate obstruction or invasion of the ureters and bladder by the primary lesion, and provide information on evacuation efficiency as evidenced by residual urine on voiding and postvoiding films. The incidence of abnormal preoperative urograms was 30 per cent in some series; 4 • 24• 34 however, of these abnormalities, 25 per cent were anatomic variations and 75 per cent were nonsignificant urologic diseases.
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None of the postoperative urologic complications was related to the radiologic findings. The history or radiologic findings may indicate the need for endoscopic or urodynamic evaluation. Cystourethroscopy will define structural abnormalities, establish the presence or absence of outlet obstruction, and rule out extension of malignant disease. Urodynamic evaluation is helpful in determining unsuspected neurologic abnormalities and supplements an overall view of vesicourethral function.
URODYNAMIC FINDINGS Vesicourethral dysfunction after abdominoperineal resection should be evaluated urodynamically. Most series document cystometric findings of a parasympathetic nerve injury with resulting sensory and motor abnormalities of detrusor function. 17• 20• 23 • 31 • 35• 42 Although cystometry is useful for determining the presence or absence of a detrusor reflex, 26 it alone does not provide a complete picture of vesicourethral function. The dynamic interaction between the pathologic detrusor and the urethral sphincter mechanism must be determined in the patient with detrusor hypofunction in order to institute appropriate therapy. McGuire has shown that isolated or combined dysfunction of the smooth and striated muscles of the sphincter mechanism can occur after abdominoperineal resection. 30 This is significant when spontaneous voiding does not occur and prostatic hypertrophy is considered the cause of the dysfunction. Prostatectomy in the presence of sphincter dysfunction may not relieve the problem and may result in incontinence. U rodynamic evaluation with fluoroscopic control can most accurately define detrusor-urethral coordination and the level of urinary continence. In the presence of a detrusor contraction and relaxation of the striated external sphincter, persistent closure of the prostatic urethra is diagnostic of prostatic obstruction and prostatectomy is indicated. If continence occurs at the striated external sphincter and the proximal urethra is patulous, pudendal nerve function is intact and prostatectomy is not likely to be helpful. If continence is maintained at the neck of the bladder, the internal sphincter is intact, but the striated external sphincter may or may not be functional. Striated external sphincter activity can be assessed by fluoroscopy, electromyography, or urethral pressure profilometry. With impairment of striated muscle function, a prostatectomy will result in incontinence. With complete smooth and striated muscle dysfunction, the patient is totally incontinent in the upright position. When prostatic obstruction is not a consideration, detrusor areflexia may exist with coordinated sphincter activity. This condition has been successfully managed by cholinergic stimulation with bethanechol chloride. 26 With a nonrelaxing internal sphincter, bethanechol with phenoxybenzamine has been useful. 25 The striated external urethral sphincter in patients with neurogenically mediated detrusor areflexia may not relax appropriately with attempts at voiding. Intermittent catheterization can be employed, as external sphincterotomy can result in severe incontinence.
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SEXUAL DYSFUNCTION Although sexual dysfunction is common after abdominoperineal resection, the exact incidence is difficult to determine for several reasons. The age of the patient and the extent of disease are important factors. 3 • 22 • 39 • 46 Stahlgren found less alteration in sexual function in patients in the sexually active years who were operated upon for benign disease. 39 Aso reported that sexual disturbances were more common in patients over 60 years of age and in those undergoing more formidable surgical procedures. 3 However, patients having rectal excision for malignant disease are usually much older than those having proctocolectomy for benign conditions. With improvement in their general health, many chronically ill patients will have improved sexual function. In some patients, the presence of a stoma and appliance will adversely affect sexual function. Sexual potency involves the psychic desire for sexual intercourse together with normal erection, ejaculation, and orgasm. Of the four factors involved in this process, ejaculation and erection are most often affected and orgasm and desire the least. 3 • 9 If only retrograde ejaculation occurs, it is potentially reversible with alpha-adrenergic agents, but there is no treatment for loss of seminal emission and transport. Erectile dysfunction can be successfully treated with various penile prostheses. 16• 19 • 37• 38 This risk of sexual dysfunction and therapeutic modalities should be discussed with each patient preoperatively.
SUMMARY Abdominoperineal resection is a procedure with significant morbidity. Knowledge of the neuroanatomy can help the surgeon to avoid or minimize the sequelae of neural injury.
REFERENCES 1. Amelar, R.D.: Infertility in the male. In Lewis, D. D. (ed.): Practice of Surgery. Vol. 2, Urology. Hagerstown, Maryland, Harper and Row, 1971. 2. Ashley, F., and Anson, B.: The pelvic autonomic nerves in the male. Surg. Gynecol. Obstet., 82:598, 1946. 3. Aso, R., and Yasutomi, M.: Urinary and sexual disturbances following radical surgery for rectal cancer, and pudendal nerve block as a countermeasure for urinary disturbance. Amer. J. Proctol., 25:60, 1974. 4. Barbaric, Z. L., Wolfe, D. E., and Segal, A. J.: Urinary tract after abdominoperineal resection. Radiology, 128:345, 1978. 5. Bartizal, J,, and Slosberg, P. A.: Combined abdominoperineal resection. SuRG. CLJN. NORTH AM., 57:1253, 1977. 6. Benson, G. S.: Mechanisms of penile erection. Invest. Urol., 19:65, 1981. 7. Benson, G. S., McConnell, J. A., and Schmidt, W. A.: Penile "polsters:" Functional structures or atherosclerotic changes? J. Urol., 125:800, 1981. 8. Bernstein, W. C., and Bernstein, E. F.: Sexual dysfunction following radical surgery for cancer of the rectum. Dis. Col. Rectum, 9:328, 1966. 9. Bors, E., and Comarr, A. E.: Neurological disturbances of sexual function with special reference to 529 patients with spinal cord injury. Urol. Survey, 10:191, 1960. 10. Conti, G.: L' erection du penis humain et ses bases morphologico-vasculaires. Acta Anat. (Basel), 14:217, 1952.
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11. Cook, E. N., Ten Cate, H. W., and Potter, W. M.: Urinary retention following operations on the bowel. J. Urol., 89:255, 1963. 12. DeGroat, W. C.: Nervous control of the urinary bladder of the cat. Brain Res., 87:201, 1975. 13. DeGroat, W. C., and Theobald, R. J.: Reflex activation of sympathetic pathways to vesical smooth muscle and parasympathetic ganglia by electrical stimulation of vesical afferent. J. Physiol. (Lond.), 259:223, 1976. 14. Domer, F. R., Wessler, G., Brown, R. L., eta!.: Involvement of the sympathetic nervous system in the urinary bladder internal sphincter and in penile erection in the anesthetized cat. Invest. Urol., 15:404, 1978. 15. Eickenberg, H. U., Amin, M., Klompus, W., eta!.: Urologic complications following abdominoperineal resection. J. Urol., 115:180, 1976. 16. Finney, R. P.: New hinged silicone penile implant. J. Urol., 118:585, 1977. 17. Fowler, J. W.: Bladder function following abdominoperineal excision of the rectum for carcinoma. Brit. J. Surg., 60:574, 1973. 18. Fowler, J. W., Bremner, D. N., and Moffat, L. E. F.: The incidence and consequences of damage to the parasympathetic nerve supply to the bladder after abdominoperineal resection of the rectum for carcinoma. Brit. J. U rol., 50:95, 1978. 19. Furlow, W. L.: Surgical management of impotence using inflatable penile prosthesis. Experience with 36 patients. Mayo Clin. Proc., 51:325, 1976. 20. Gerstenberg, T. C., Nielson, M. L., Clausen, S., eta!.: Bladder function after abdominoperineal resection of the rectum for anorectal cancer. Ann. Surg., 191:81, 1980. 21. Glass, R. L., and Spratt, J. S.: Urinary complications after abdominoperineal resection of the rectum in men. Am. Surgeon, 34:238, 1968. 22. Goligher, J.: Surgery of the Anus, Rectum and Colon, 3rd ed. London, Bailliere Tindall, 1975. 23. Kontturi, M., Larmi, T. K. I., and Tuononen, S.: Bladder dysfunction and its manifestations following abdominoperineal extirpation of the rectum. Ann. Surg., 179:179, 1974. 24. Kramhoft, J., Kronberg, 0., Backer, 0. G., eta!.: Urologic complications after operations for anorectal cancer, with an evaluation of pre-operative intravenous pyelography. Dis. Col. Rectum, 18:118, 1975. 25. Krane, R. J., and Olsson, C. A.: Phenoxybenzamine in neurogenic bladder dysfunction. II. Clinical considerations. J. Urol., 110:653, 1973. 26. Lapides, J., Friend, C. R., Ajemian, E. P., eta!.: Denervation supersensitivity as a test for neurogenic bladder. Surg. Gynecol. Obstet., 114:241, 1962 27. Leadbetter, G. W., and Leadbetter, W. F.: A new approach to the problem of urinary retention following abdominoperineal resection for carcinoma of the rectum. Surg. Gynecol. Obstet., 107:333, 1958. 28. Lee, J. F., Maurer, V. M., and Block, G. E.: Anatomic relations of pelvic autonomic nerves to pelvic operations. Arch. Surg., 107:324, 1973. 29. McGuire, E. J.: Urodynamic evaluation after abdominal-perineal resection and lumbar intervertebral disk herniation. Urology, 6:63, 1975. 30. McGuire, E. J.: Neurovesical dysfunction after abdominoperineal resection. SURG. CLIN. NORTH AM., 60:1207, 1980. 31. Marshall, V. F., Pollack, R. S., and Miller, C.: Observations on urinary dysfunction after excision of the rectum. J. U rol., 55:409, 1946. 32. Miles, W. E.: A method of performing abdominoperineal excision for carcinoma of the rectum and of the terminal portion of the pelvic colon. Lancet, 2:1812, 1908. 33. Polak, J. M., Mina, S., Gu, J., eta!.: Vipergic nerves in the penis. Lancet, 2:217, 1981. 34. Prager, E., Swinton, N. W., Corman, M. L., eta!.: Intravenous pyelography in colorectal surgery. Dis Col. Rectum, 16:479, 1973. 35. Rankin, J. T.: Urological complications of rectal surgery. Brit. J. Urol., 41:655, 1969. 36. Schirger, A., and Gifford, R. W.: Guanethidine, a new antihypertensive agent: Experience in the treatment of 36 patients with severe hypertension. Proc. Mayo Clin., 37:100, 1962. 37. Scott, F. B., Bradley, W. E., and Timm, G.: Management of erectile impotence. Use of implantable inflatable prosthesis. Urology, 2:80, 1973. 38. Small, M. D., and Carrion, H. M.: A new penile prosthesis for treating impotence. Con temp. Surg., 7:29, 1975. I
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39. Stahlgren, L. H., and Ferguson, L. K.: Influence on sexual function of abdominoperineal resection for ulcerative colitis. New Engl. J. Med., 259:873, 1958. 40. Tank, E. S., Ernst, C. B., Woolson, S. T., eta!.: Urinary tract complications of anorectal surgery. Am. J. Surg., 123:118, 1972. 41. Ward, J. N., and Nay, H. R.: Immediate and delayed urologic complications associated with abdominoperineal resection. Am. J. Surg., 123:642, 1972. 42. Watson, P. C., and Williams, D. I.: The urological complications of exicision of the rectum. Brit. J. Surg., 40:19, 1952. 43. Weinstein, M., and Roberts, M.: Sexual potency following surgery for rectal carcinoma: A following-up of 44 patients. Ann. Surg., 185:295, 1977. 44. Weiss, H. D.: The physiology of human penile erection. Ann. Intern. Med., 76:793, 1972. 45. Whitelaw, G. P., and Smithwick, R. H.: Some secondary effects of sympathectomy with particular reference to disturbance of sexual function. New Engl. J. Med., 245:121, 1951. 46. Yeager, E. S., and Van Heerden, J. A.: Sexual dysfunction following proctocolectomy and abdominoperineal resection. Ann. Surg., 191:169, 1980. Division of Urology Department of Surgery Washington University Medical Center 4960 Audubon Avenue St. Louis, Missouri 63110