SURGICAL ANATOMY OF THE SOMATIC TERMINAL INNERVATION TO THE ANAL AND URETHRAL SPHINCTERS: ROLE IN ANAL AND URETHRAL SURGERY

Uroflow stop test with electromyography: a novel index of urinary continence recovery after RARP

PURPOSE

Urinary incontinence (UI) is one of the most bothersome surgical side effects after robot-assisted radical prostatectomy (RARP). Alteration of both smooth and striate urethral sphincter occurs after RARP. Since the contraction of perineal muscles is involved in the complex mechanism of urinary continence, the uroflow stop test (UST) seems to predict early continence recovery after RARP. The UST was added of perineal surface electromyography (EMG) evaluation to evaluate the latency time (LT) between muscular contraction and the complete stop of urine flow. Our aim was to present UST-EMG as a new tool in the investigation of UI, implying pelvic floor integrity, and to evaluate whether an early return (≤ 3 months) to preoperative LT could be associated with early recovery of UC (≤ 3 months).

METHODS

After prospectively enrolling 137 patients who underwent RARP with a minimum follow-up of 6 months, we identified two groups: Group 1 (93 patients) with early (≤ 3 months) pre-surgical LT recovery and Group 2 (44 patients) with late > 3 months or not able to reach pre-surgical LT recovery.

RESULTS

Between the two groups, there were significant differences in terms of different surgical technique (nerve-sparing versus non-nerve-sparing) and pads use at 3 and 6 months after RARP (p < 0.05). No differences were recorded neither in postoperative maximum flow-rate, nor in postoperative symptoms score.

CONCLUSIONS

UST with EMG can be considered as a noninvasive, reproducible and easily performable tool. LT is applicable in the clinical evaluation to predict urinary continence recovery after RARP.

Anatomy and nerve supply of the pelvic floor

In order to guarantee urinary and fecal continence as well as correct pelvic statics, the perfect neuroanatomical integrity of the pelvic floor muscles is mandatory. As Dickinson stated: “There is no considerable muscle in the body whose form and function are more difficult to understand than those of the levator ani, and about which such nebulous impressions prevail”. Clinical implications of pelvic floor anatomy and nerve supply are evident: a denervation of this muscle group and the consequent muscle dysfunction could result in urinary and/or fecal incontinence, as well as pelvic organ prolapse.

Preservation of the neurovascular bundles is associated with improved time to continence after radical prostatectomy but not long-term continence rates: results of a systematic review and meta-analysis

CONTEXT

The aetiology of urinary incontinence following radical prostatectomy (RP) is incompletely understood. In particular, it is unclear whether there is a relationship between neurovascular bundle (NVB) sparing and post-RP urinary continence.

OBJECTIVE

To review systematically the association of NVB sparing in RP with postoperative urinary continence outcomes and synthesise the results in a meta-analysis.

EVIDENCE ACQUISITION

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. PubMed, Medline, and Cochrane Central Register of Controlled Trials were searched (December 2013), yielding 3413 unique records. A total of 27 longitudinal cohort studies were selected for inclusion. Studies were evaluated using a predefined criteria adapted from the Cochrane Tool to Assess Risk of Bias in Cohort Studies.

EVIDENCE SYNTHESIS

Data from 13 749 participants in 27 studies were synthesised in a meta-analysis. An assessment of the study methodology revealed a high risk of bias due to differences in baseline characteristics, outcome assessment, and the likely presence of unreported confounding factors such as meticulous apical dissection. Meta-analysis demonstrated that nerve sparing (NS) compared with non-nerve sparing (NNS) resulted in improved early urinary continence rates up to 6 mo postoperatively. Beyond this time, no significant difference was observed. This effect was seen most clearly for bilateral NS compared with NNS. A sensitivity analysis of prospective cohort studies revealed consistent results.

CONCLUSIONS

This analysis demonstrates an association between NS and improved urinary continence outcomes up to 6 mo postoperatively. NS in men with poor preoperative erectile function should be considered in the context of oncologic risk stratification because it may improve time to continence recovery. The underlying cause of the relationship between NS and continence is unknown. It may represent preservation of the intrapelvic somatic nerves supplying the rhabdosphincter or the influence of other confounding factors. Future research should be directed towards improving understanding of the anatomy of urinary continence and the pathophysiology of post-RP incontinence.

PATIENT SUMMARY

We found that avoiding damage to the nerves around the prostate improves urinary continence in the first 6 mo after surgery. After this time, there is no difference in continence between men who had these nerves removed and those who had them saved. This finding could be due to a true effect of saving these nerves or to a number of other factors affecting the research.

The Pudendal Nerve and Its Branches in Relation to Richter's Procedure

OBJECTIVE

Variations in the branching pattern of the pudendal nerve (PN) have been described in the literature. This study investigated these variations in order to comment on a safe area for the placement of a Richter's stitch.

METHODS

Richter's procedure was performed on nine unembalmed female cadavers and followed by dissection. PN dissections were done on another 20 embalmed female cadavers. Variations in the branching pattern of the PN were noted and the distance between the Richter's stitch placed and the PN/or the inferior rectal nerve (IRN) measured.

RESULTS

The IRN entered the gluteal region as a separate structure in 6/29 cases. The separate IRN was found to pass between 4.1 and 14.45 mm medial to the ischial spine in 18/29 cases. In one case, the Richter's stitch was found to pierce the IRN. The distance between the stitch and the PN and/or the IRN ranged from 0 to 17.8 mm.

CONCLUSIONS

To minimize the risk of nerve damage or entrapment, the Richter's stitch should be placed >20 mm from the ischial spine. This recommended area should be revised for different population groups, as variations might exist between groups.

Predicting risk of erectile dysfunction after pelvic fracture urethral injury in children

PURPOSE

We sought to determine the incidence of erectile dysfunction following pelvic fracture urethral injuries in children, and to identify the related causes and risk factors.

MATERIALS AND METHODS

All consecutive children who had undergone repair of a pelvic fracture urethral injury between 1980 and 2010 were invited to participate in the study. All responders were queried after a median of 13 years (range 3 to 28) following trauma to assess erectile function using the erectile function domain of the International Index of Erectile Function. Patients who had erectile dysfunction underwent penile duplex ultrasonography. Medical records and imaging studies were reviewed with a focus on 4 variables, ie pattern of pelvic fracture, pubic diastasis, prostatic displacement and urethral gap length. Univariate and multivariate analyses were used to identify parameters predictive of erectile dysfunction at puberty.

RESULTS

A total of 60 patients participated in the study, of whom 28 (47%) had erectile dysfunction. On univariate analysis all 4 parameters were significant predictors of erectile dysfunction, while on multivariate analysis only 2 parameters remained strong and independent predictors, namely urethral gap length 2.5 cm or greater and prostatic displacement in a lateral direction. Duplex ultrasound revealed the cause of erectile dysfunction as arteriogenic in 19 patients (76%), arteriovenogenic in 2 (8%) and likely neurogenic in 4 (16%).

CONCLUSIONS

For every 2 children sustaining a pelvic fracture urethral injury 1 will exhibit erectile dysfunction at puberty. The risk of erectile dysfunction is appreciably increased in the presence of a long urethral gap and/or lateral prostatic displacement. The cause of erectile dysfunction is most commonly primarily arteriogenic and less commonly neurogenic.

Novel uroflow stop test at time of catheter removal is a strong predictor of early urinary continence recovery following robotic-assisted radical prostatectomy: a pilot study

AIM

To study whether the ability to completely stop urinary flow during voiding at time of catheter removal, measured objectively using uroflowmetry, can predict early recovery of urine continence following robotic-assisted radical prostatectomy (RARP).

MATERIALS AND METHODS

In this pilot study, 108 patients with a minimum of 2 years follow-up, operated by a single surgeon (AEH) were subjected to an uroflowmetry at the time of urethral catheter removal following RARP. Normal Saline (150 ml) was instilled intravesically prior to catheter removal and patients were instructed to attempt to stop urine flow during voiding in uroflowmeter. Two groups were studied, group one with positive Stop Test (n = 80) and group two with negative Stop Test (n = 28). Covariates included age, BMI, IPSS score, PSA, tumor stage, prostate volume, nerve sparing status, and estimated blood loss.

RESULTS

Basic characteristics were not statistically different between both groups. Early continence recovery was significantly higher in group one. Pad-free continence rates in group one and two at 1, 3, 6, 12, 18, and 24 months were 62% vs. 7% (P < 0.001), 85% vs. 28% (P < 0.001), 93% vs. 67% (P 0.001), 93% vs. 82% (P 0.079), 97% vs. 82% (P 0.006), and 97% vs. 85% (P 0.023), respectively. Uroflow Stop Test was the only independent predictor of early urine continence recovery on univariate and multivariate regression analysis [OR 2.87 (95%CI 1.34-4.38, P = < 0.001)].

CONCLUSION

Novel use of uroflowmetry at time of urethral catheter removal is a simple, non-invasive study with independent ability to predict early continence recovery following RARP.

Anatomic variations of the pelvic floor nerves adjacent to the sacrospinous ligament: a female cadaver study

Our objective was to document variations in the topography of pelvic floor nerves (PFN) and describe a nerve-free zone adjacent to the sacrospinous ligament (SSL). Pelvic floor dissections were performed on 15 female cadavers. The course of the PFN was described in relation to the ischial spine (IS) and the SSL. The pudendal nerve (PN) passed medial to the IS and posterior to the SSL at a mean distance of 0.6 cm (SD = +/-0.4) in 80% of cadavers. In 40% of cadavers, an inferior rectal nerve (IRN) variant pierced the SSL at a distance of 1.9 cm (SD = +/-0.7) medial to the IS. The levator ani nerve (LAN), coursed over the superior surface of the SSL-coccygeus muscle complex at a mean distance of 2.5 cm (SD = +/-0.7) medial to the IS. Anatomic variations were found which challenge the classic description of PFN. A nerve-free zone is situated in the medial third of the SSL.

Innervation of the levator ani muscles: description of the nerve branches to the pubococcygeus, iliococcygeus, and puborectalis muscles

We described the innervation of the levator ani muscles (LAM) in human female cadavers. Detailed pelvic dissections of the pubococcygeus (PCM), iliococcygeus (ICM), and puborectalis muscles (PRM) were performed on 17 formaldehyde-fixed cadavers. The pudendal nerve and the sacral nerves entering the pelvis were traced thoroughly, and nerve branches innervating the LAM were documented. Histological analysis of nerve branches entering the LAM confirmed myelinated nerve tissue. LAM were innervated by the pudendal nerve branches, perineal nerve, and inferior rectal nerve (IRN) in 15 (88.2%) and 6 (35.3%) cadavers, respectively, and by the direct sacral nerves S3 and/or S4 in 12 cadavers (70.6%). A variant IRN, independent of the pudendal nerve, was found to innervate the LAM in seven (41.2%) cadavers. The PCM and the PRM were both primarily innervated by the pudendal nerve branches in 13 cadavers (76.5%) each. The ICM was primarily innervated by the direct sacral nerves S3 and/or S4 in 11 cadavers (64.7%).

Pelvic Autonomic Nerve Mapping Around the Prostate by Intraoperative Electrical Stimulation With Simultaneous Measurement of Intracavernous and Intraurethral Pressure

PURPOSE

In previous studies we noted that the neurovascular bundle was not identical to the bundle of the cavernous nerve fibers. In this study we sought to prove these anatomical findings electrophysiologically and map the autonomic nerve fibers by intraoperative simultaneous measurement of intracavernous pressure and intraurethral pressure.

MATERIALS AND METHODS

Between January 2004 and May 2005 electrical stimulation was performed in 27 open pelvic surgeries, including 26 radical retropubic prostatectomies and 1 radical cystectomy, using an original bipolar electrode before prostate removal. Nerve stimulation was performed at the base of the so-called neurovascular bundle (point A) and the rectal wall about 1 cm posterolateral, apart from the neurovascular bundle (point B). Intracavernous pressure and intraurethral pressure were measured simultaneously.

RESULTS

The mean +/- SD increase in intracavernous pressure was 9.8 +/- 6.3 cm H2O at point A and 13.5 +/- 7.3 cm H2O at point B. Intracavernous pressure at point B was significantly higher than at point A (p = 0.0240). The mean increase in intraurethral pressure was 17.0 +/- 9.4 cm H2O at point A and 11.2 +/- 8.1 cm H2O at point B. Intraurethral pressure at point A was significantly higher than at point B (p = 0.0353).

CONCLUSIONS

The course of the cavernous nerves did not always agree with the surgically identified neurovascular bundle. The distribution of cavernous nerves was wider than our image of the neurovascular bundle and it existed on the rectal wall posterolateral, apart from the neurovascular bundle rather than the neurovascular bundle itself. The surgically identified neurovascular bundle contained the nerve fibers contributing to urinary continence.

Pudendal nerve branch injury during radical perineal prostatectomy

We report the first case of direct surgical injury to a pudendal nerve branch during radical perineal prostatectomy. A 65-year-old patient presented with typical symptoms of a pudendal nerve lesion after radical perineal prostatectomy. As the patient did not respond to conservative treatment, surgical exploration and exeresis of the injured sensory branch of the pudendal nerve was necessary, resulting in pain improvement. Urologic surgeons should be aware of the typical symptoms after iatrogenic injury to the pudendal nerve or its branches. Early diagnosis and neurosurgical intervention are important to obtain a more favorable outcome.

Fascicular anatomy and surgical access of the human pudendal nerve

The ability to access selectively distal nerve branches at the level of the compound pudendal nerve (PN) would allow control of multiple neural pathways and genitourinary functions at a single location. Nerve cuff electrodes can selectively stimulate individual fascicles; however the PN fascicular anatomy is unknown. The fascicular representation of distal branches was identified and traced proximally to create fascicle maps of 12 compound PNs in seven cadavers. Distal nerves were represented as groups of individual fascicles in the PN. Fascicle maps were consistent between specimens and along the PN within specimens. PN branch free length was 26+/-7.7 mm. PN cross-sections were relatively flat with major and minor diameters of 4.3+/-0.90 and 1.7+/-0.45 mm, respectively. Placing a nerve cuff on the PN is anatomically and surgically feasible. The PN fascicular anatomy, branch free length, and cross-section geometry are conducive to selective stimulation of distal nerves with a single nerve cuff electrode.

Innervation of the Female Human Urethral Sphincter: 3D Reconstruction of Immunohistochemical Studies in the Fetus

OBJECTIVES

The precise location, origin and nature of nerve fibers innervating the urethral sphincter have not been clearly established. Classical anatomical studies based on cadaver dissections have provided conflicting results concerning the location of pudendal and autonomic nerve fibers. This study was designed to identify nerve fibers innervating the urethral sphincter and to provide a three-dimensional representation of their tissue relations in the female human fetus.

MATERIALS AND METHODS

Histology and immunohistochemistry (Masson's Trichromic, Luxol Fast Blue, Protein S 100 immunostaining and smooth fiber actin immunostaining) were performed on the external urethral sphincter of ten female fetuses with a crown-rump length of 112 to 340mm. Three-dimensional reconstructions of the urethral structure and innervation were obtained from serial sections using Surf Driver 3.5.3 software (David Moody and Scott Lozanoff).

RESULTS

Three-dimensional reconstructions of the same sections with different stains demonstrated the precise structure of the muscle layers (smooth and striated muscle fibers) and nerve fibers (myelinated and unmyelinated) and their relations with the urethra and vaginal wall. The proximal third consisted of a circular smooth muscle sphincter, the middle third consisted of two circular layers of smooth and striated muscle fibers and the distal third consisted of a circular layer of smooth muscle fibers surrounded by an omega-shaped layer of striated muscle fibers. In the proximal third of the urethral sphincter, myelinated fibers were identified running with unmyelinated fibers from the pelvic plexus. These fibers were closely related to the lateral and anterior aspects of the vagina. Unmyelinated fibers entered the smooth muscle part of the sphincter at 4 o'clock and at 8 o'clock. Most myelinated fibers entered the sphincter at 3 o'clock and at 9 o'clock.

CONCLUSION

Histological and immunohistochemical three-dimensional reconstruction of the anatomical structures of the urethral sphincter provides a better understanding of the origin and nature of the Innervation participating in urinary continence. It provides a very informative view of the three-dimensional arrangement of sphincter muscle layers.

Pudendal nerve decompression in perineology: a case series

BACKGROUND

Perineodynia (vulvodynia, perineal pain, proctalgia), anal and urinary incontinence are the main symptoms of the pudendal canal syndrome (PCS) or entrapment of the pudendal nerve. The first aim of this study was to evaluate the effect of bilateral pudendal nerve decompression (PND) on the symptoms of the PCS, on three clinical signs (abnormal sensibility, painful Alcock's canal, painful "skin rolling test") and on two neurophysiological tests: electromyography (EMG) and pudendal nerve terminal motor latencies (PNTML). The second aim was to study the clinical value of the aforementioned clinical signs in the diagnosis of PCS.

METHODS

In this retrospective analysis, the studied sample comprised 74 female patients who underwent a bilateral PND between 1995 and 2002. To accomplish the first aim, the patients sample was compared before and at least one year after surgery by means of descriptive statistics and hypothesis testing. The second aim was achieved by means of a statistical comparison between the patient's group before the operation and a control group of 82 women without any of the following signs: prolapse, anal incontinence, perineodynia, dyschesia and history of pelvi-perineal surgery.

RESULTS

When bilateral PND was the only procedure done to treat the symptoms, the cure rates of perineodynia, anal incontinence and urinary incontinence were 8/14, 4/5 and 3/5, respectively. The frequency of the three clinical signs was significantly reduced. There was a significant reduction of anal and perineal PNTML and a significant increase of anal richness on EMG. The Odd Ratio of the three clinical signs in the diagnosis of PCS was 16,97 (95% CI = 4,68 - 61,51).

CONCLUSION

This study suggests that bilateral PND can treat perineodynia, anal and urinary incontinence. The three clinical signs of PCS seem to be efficient to suspect this diagnosis. There is a need for further studies to confirm these preliminary results.

NEUROANATOMY OF THE HUMAN FEMALE LOWER UROGENITAL TRACT

PURPOSE

The neuroanatomy of the female lower urogenital tract remains controversial. We defined the topographical anatomy and differential immunohistochemical characteristics of the dorsal nerve of the clitoris, the cavernous nerve and the nerves innervating the female urethral sphincter complex.

MATERIALS AND METHODS

A total of 16 normal female human pelvic specimens at 14 to 34 weeks of gestation were studied by immunohistochemical techniques. Serial sections were stained with antibodies raised against the neuronal markers S-100 and neuronal nitric oxide synthase (nNOS), vesicular acetylcholine transporter, calcitonin gene-related peptide and substance P. The serial sections were computer reconstructed into 3-dimensional images.

RESULTS

Under the pubic arch at the hilum of the clitoral bodies the branches of the cavernous nerves joined the clitoral dorsal nerve to transform its immunoreactivity to nNOS positive. The cavernous nerves originated from the vaginal nervous plexus occupying the 2 and 10 o'clock positions on the anterolateral vagina and they traveled at the 5 and 7 o'clock positions along the urethra. The urethral sphincter complex was innervated by nNOS immunoreactive and nonimmunoreactive nerve fibers arising from the vaginal nervous plexus and pudendal nerve, respectively.

CONCLUSIONS

The dorsal nerve of the clitoris receives nNOS positive branches from the cavernous nerve as a possible redundant mechanism for clitoral erectile function. The urethral sphincter complex has dual innervation, which pierces into the urethral sphincter complex at different locations. The study of the neuroanatomy of the female lower urogenital tract is germane to the strategic design of female reconstructive surgery.

Innervation of the female levator ani muscles

OBJECTIVE

The objective of this study was to characterize the innervation of the human female levator ani muscles.

STUDY DESIGN

Detailed dissections of the peripheral innervation of the iliococcygeal, pubococcygeal, puborectal, and coccygeal muscles were performed in 12 fresh-frozen female cadavers (aged, 32-100 years) with the use of transabdominal, gluteal, and perineal approaches. Both the pudendal nerve and the sacral nerve roots that enter the pelvis from the cephalic side were followed from their origin at the sacral foramina to their termination. Pelvic floor innervation was described with reference to fixed bony landmarks, particularly the coccyx, the ischial spine and the inferior pubis. Photographs were taken, and nerve biopsies were performed to confirm the gross findings histologically. Biopsy specimens were stained with Masson's trichrome.

RESULTS

In each dissection, a nerve originated from the S3 to S5 foramina (S4 alone, 30%; from S3 and S4, 40%; from S4 and S5, 30%), crossed the superior surface of the coccygeal muscle (3.0 +/- 1.4 cm medial to the ischial spine [range, 1.0-4.2 cm]), traveled on the superior surface of the iliococcygeal muscle innervating it at its approximate midpoint, and continued on to innervate both the pubococcygeal and puborectal muscles at their approximate midpoint. The pudendal nerve originated from the S2 to S4 foramina, exited the pelvis through the greater sciatic foramen, traversed Alcock's canal, and branched to innervate the external anal sphincter, the external urethral sphincter, the perineal musculature, the clitoris, and the skin. Despite specific attempts to locate pudendal branches to the levator ani, none could be demonstrated. Nerve biopsy specimens that were obtained at gross dissection were confirmed histologically.

CONCLUSION

Gross dissections suggest that the female levator ani muscle is not innervated by the pudendal nerve but rather by innervation that originates the sacral nerve roots (S3-S5) that travels on the superior surface of the pelvic floor (levator ani nerve). Because definitive studies (eg, nerve transection or neurotracer studies) cannot be performed in humans, further studies that will use appropriate animal models are necessary to confirm and extend our findings.

Individual variations in aging of the male urethral rhabdosphincter in Japanese

Although the degenerative changes with aging of the male urethral rhabdosphincter (URS) have been investigated, its individual morphological variations are still unclear. To provide an anatomical basis for clinical evaluation of the individual URS function in the aged, we investigated the structural differences in the URS of 25 elderly Japanese men using semiserial sections stained immunohistochemically and by hematoxylin-eosin. Before removal of the histological specimens, we dissected the ischioanal fossa and labeled several structures by carbon particles to allow proper orientation during the histological observations. In addition, macroscopic slices (10 mm thickness) made from five other male pelves were examined and, when necessary, followed by routine histological procedure to confirm the gross observations. An extended circular URS (over (1/2) circumferential configuration) was found in 15/25 cadavers, but showed very limited height (proximal-distal length) and thickness. A more restricted URS, including even a thin, arc-like pattern, was observed in the remaining cadavers. The attachment of the URS to the smooth muscle layer was loose and usually clearly separated. Continuation between the URS and deep transverse perineal muscle was sometimes observed. The thick fascia of the levetor ani, with high content of smooth muscles, usually provided the lateral or dorsal insertions of the URS. Our results in elderly Japanese subjects suggest that the sphincteric action is weak or incomplete. We suggest that the elderly URS maintains continence by retracting the urethra backward and upward with the aid of the levator sling, rather than the real sphincteric action expected in younger men.

Rectal inhibition by inferior rectal nerve stimulation in dogs: recognition of a new reflex--the 'voluntary anorectal inhibition reflex'

OBJECTIVE

The effect of inferior rectal nerve (IRN) stimulation on the rectum was studied, postulating that nerve stimulation might inhibit rectal contractility and could thus be used in the management of defecation disorders.

METHOD

The IRN was exposed through a para-anal incision in 12 dogs (18.2 +/- 3.3 SD kg, seven male, five female) and a cuff-type electrode was applied to the nerve. A balloon introduced into the rectum was filled with saline in increments of 5 ml. The rectal and rectal neck (anal canal) pressures, and the electromyographic (EMG) activity of the external anal sphincter (EAS) and Internal anal sphincter (IAS) were recorded until the balloon was expelled to the exterior. The test was repeated until the expulsion volume was reached, and the IRN was stimulated (pulse width 200 mu/s, charge density 2 to 6 microCi/cm2 per phase). The test was performed again following individual anaesthetization of the EAS and the IAS.

RESULTS

At a mean rectal distending volume of 38.3 +/- 2.3 ml, the rectal pressure increased (P < 0.01), rectal neck pressure declined (P < 0.01), the EAS and IAS EMGs disappeared, and the balloon was expelled. IRN stimulation at a distending volume of 38.3 +/- 2.3 ml increased the EMG activity of the EAS, whereas the rectal pressure and IAS EMG did not change (P > 0.05) and the balloon was not expelled. With IRN stimulation at the distending volume of 38.3 +/- 2.3 ml while the EAS was anaesthetized, the rectal pressure increased (P < 0.01), rectal neck pressure diminished, IAS EMG activity disappeared, and the balloon was expelled. Upon repetition of IRN stimulation during anaesthetization of the IAS, the rectal pressure remained high and the balloon was not expelled.

CONCLUSION

It is suggested that the EAS produces continence by a twofold action. The EAS prevents IAS relaxation on rectal contraction, with a resulting rectal relaxation. A reflex relationship is postulated to exist between failure of the IAS to relax and rectal relaxation. We call this reflex relationship 'voluntary anorectal inhibition reflex'. Secondly, the EAS mechanically compresses the rectal neck. It seems that contraction of the EAS, which is a striated muscle, mechanically occludes the rectal neck for a few seconds--enough for the rectum to relax in a reflex manner as an effect of the voluntary anorectal inhibition reflex.

Neuronal innervation of urethral and anal sphincters: surgical anatomy and clinical implications

The present review describes the neuronal innervation of the external urethral and anal sphincters. A knowledge of this innervation helps in understanding the clinical symptoms of urinary and anorectal pathology, and in choosing the appropriate technique of nerve localization or block. An ability to locate the pudendal nerve, on the basis of surgically documented anatomy, has important diagnostic and therapeutic advantages. It can be used to study the integrity of pelvic floor muscles, in biofeedback training, nerve blocks, pudendal canal decompression, chronic stimulation trials to treat urinary or faecal incontinence, and in nerve conduction studies or evoked potential recordings. Furthermore, the superficial location of the sphincteric innervation in the perineum and ischiorectal fossa renders the nerve branches susceptible to injury during operative correction of urinary or faecal incontinence. Supported by a knowledge of anatomy, we can make firm recommendations on which to base safe surgical techniques that avoid damage to urethral and anal sphincteric innervation.

Evaluation of male sexual function after pelvic trauma by the International Index of Erectile Function

OBJECTIVES

To assess the multifaceted male sexual function after pelvic ring fracture.

METHODS

A cross-sectional study of male sexual function after pelvic ring fractures was conducted, using the International Index of Erectile Function (IIEF). The department of traumatology database was scanned (June 1996 to April 1999) for 30 to 70-year-old male patients with pelvic fracture. Seventy-six consecutive, literate patients were then contacted by mail. IIEF domain scores were calculated for all responders. Cappelleri's method for identification and grading of erectile dysfunction was applied for patients sexually active within the past 4 weeks. Student's t test was used to compare the domain scorings of patients with those of the control population used for the IIEF psychometric validation. Relationships between IIEF results and patient characteristics were sought by Spearman's rank correlation coefficient for quantitative variables and Student's t test for classes.

RESULTS

Forty-six patients answered (60.1% response rate). Thirty-seven patients had experienced sexual intercourse in the past 4 weeks during which 11 patients (29.7%) had exhibited various degrees of impaired erection. As a whole, compared with the published controls a significant decrease in overall satisfaction (P <0.05) was demonstrated. Pubic diastasis was further related to impaired erectile function and overall satisfaction; we suggest that cavernosal nerves might be damaged at the time of diastasis.

CONCLUSIONS

This study evidenced the impairment of sexual overall satisfaction after pelvic trauma and the specific decrease in erectile function and erection firmness and confidence associated with pubic diastasis. The IIEF questionnaire might be considered at the time of rehabilitation to identify those patients that could benefit from supportive treatments.