External anal sphincter repair using the overlapping technique in patients with anal incontinence and concomitant pudendal nerve damage

BACKGROUND: No single surgical technique has so far emerged as the optimal approach to treat defects of the anal sphincter in patients with postpartum fecal incontinence. Our approach is to repair the external sphincter using the overlapping technique to optimize morphological and clinical outcome. The results were correlated with preoperatively determined pudendal nerve function. METHODS: Thirty-five patients were followed up for three years after repair of the external anal sphincter. The patients had grade 2 (n = 29) or grade 3 (n = 6) fecal incontinence. Nineteen (54 %) patients had a concomitant defect of the internal anal sphincter and 28 (80 %) had abnormal pelvic floor EMG findings. Before surgery, all patients underwent conservative treatment with biofeedback and electrostimulation. The muscle ends were overlapped with Vicryl 4-0 sutures. A standardized protocol was used for the perioperative management in all patients. RESULTS: Of the 35 patients who underwent overlapping repair of the external anal sphincter, 32 (91 %) had a satisfactory result at 3-year follow-up based on sonomorphological criteria. These 32 patients were continent for solid and liquid stools. Six of the 35 patients (17 %) continued to have flatus incontinence. Two (6 %) patients were improved and one patient (3 %) had unchanged incontinence. Pudendal nerve damage had no effect on the outcome of surgery. CONCLUSIONS: Our findings at 3-year follow-up show good results for the overlapping repair of the external anal sphincter in terms of morphology and clinical symptoms. This outcome depends on an adequate preoperative pelvic floor conditioning, optimal perioperative management, and use of a standardized operative technique. Surgical repair of the morphological defect is recommended even in patients with pudendal nerve damage.     

Restoration of external urethral sphincter function after pudendal nerve end-to-end anastomosis in the male rabbit

PURPOSE: In this study we rehabilitated external urethral sphincter function by pudendal nerve end-to-end anastomosis after experimental pudendal nerve axotomy in male rabbits. MATERIALS AND METHODS: A total of 17 animals were included in this study, including group 1-a control group of 5 (29.4%), group 2-6 (35.3%) and group 3-6 (35.3%). Animals from group 2 underwent bilateral axotomy and group 3 underwent pudendal nerve end-to-end anastomosis. In all groups we performed urodynamic investigations prior to axotomy, after axotomy or anastomosis, and 14, 42 and 90 days after axotomy or nerve anastomosis. RESULTS: In untreated group 1 control sphincter pressure was 28.5 cm H2O. In group 2 average urethral sphincter pressure was 5.6 cm H2O 14 days after axotomy with only a slight increase to 11.05 cm H2O by day 90. In group 3 external urethral pressure increased to 8.26 cm H2O after 14 days and to 21.32 cm H2O by postoperative day 90. CONCLUSIONS: External urethral sphincter deficiency after bilateral pudendal nerve axotomy demonstrates the primacy of the pudendal nerve in the innervation of the external urethral sphincter. We were able to rehabilitate external urethral sphincter function by performing pudendal nerve end-to-end anastomosis.     

External urethral sphincter activity in a rat model of pudendal nerve injury

AIMS: Pudendal nerve injury in the rat has been a useful animal model for studying stress urinary incontinence (SUI). However, the effect of pudendal nerve injury on activity of the external urethral sphincter (EUS) is relatively unexplored. The aims of this study were to examine voiding and the EUS electromyogram (EMG) in a durable SUI model in rats with bilateral or unilateral pudendal nerve transections. In addition, the effects of denervation on urethral anatomy were investigated. METHODS: A leak point pressure (LPP) test was first used to demonstrate that pudendal nerve transection induced SUI. Cystometry exhibited changes in voiding function and EUS-EMG measurements provided a quantitative evaluation of EUS activity during voiding. The morphological changes in sections through the mid-urethra were assessed with hematoxylin and eosin (H&E) staining. RESULTS: A significant decrease in average LPP was detected in rats 6 weeks after bilateral pudendal nerve transection (BPNT). Abnormal urodynamic measurements including a decrease in contraction amplitude and voided volume as well as an increase in contraction duration, and residual volume all indicated inefficient voiding. In addition EUS-EMG silent periods were reduced and the frequency of EUS-EMG bursting during voiding was increased. Atrophy of striated muscle in the EUS was also detected in rats with pudendal nerve transection(s). CONCLUSIONS: Our results indicate that pudendal nerve transection in rats decreases urethral outlet resistance and causes striated muscle atrophy in the EUS, EUS-EMG abnormalities and inefficient voiding. The results demonstrate that BPNT is a durable model for SUI.     

End-to-side anastomosis of the vein: a technical innovation

A new technique for easier end-to-side anastomosis of veins is presented. By applying a few traction sutures to the edge of the venotomy and tenting the venous wall, thereby keeping the venotomy open, end-to-side anastomosis of the vein can be easily performed.     

Topographic anatomy of a new posterior approach to the pudendal nerve for stimulation

OBJECTIVES: To describe a new approach to the pudendal nerve from a dorsal direction in terms of topographic anatomy and to discuss pudendal nerve neurophysiology in light of the rationale behind pudendal nerve stimulation to treat lower urinary tract disorders. MATERIALS AND METHODS: Cadavers of four women aged 78-87 yr were studied. After placing the cadavers in prone position with a 40 degrees -60 degrees flexion of the hips and determining anatomic landmarks, a 20-G insulated needle was inserted close to the pudendal nerve. Then the topographic relationships of the puncture with the pudendal canal were explored by dissection. RESULTS: The mean points of insertion of the needle were 14 cm inside the great trochanter, 9 cm above the ischiatic tuberosity, and 6 cm outside the gluteal fold. If the needle was inserted 6.5 cm under the previous with an orifice of 60 degrees and this route was followed, the needle could have a contact area with the pudendal nerve larger, leading to a greater stimulation efficacy with less stimulation intensities. The rectum was so far away that a rectal injury with the needle seemed unlikely. No vascular structure was at the contact of the nerve. CONCLUSIONS: The described new puncture technique to reach the pudendal nerve provides easy and safe accessibility of the nerve for stimulation. In light of our increasing understanding of the rationale behind neuromodulative stimulation, the pudendal nerve could be a promising target for continuous lower urinary tract neuromodulation by implant.     

Anal acoustic reflectometry: a new technique for assessing anal sphincter function

Objective Anal acoustic reflectometry (AAR) is a new technique that offers an assessment of anal sphincter function by the measurement of additional parameters not available with conventional manometry. The aim of this study is to describe the technique, methodology and initial pilot study results. Method Wideband sounds (100 Hz to 16 kHz) are transmitted into a thin polyurethane bag placed within the anal canal. Calculation of cross‐sectional area from reflected sound waves, over a range of pressures (0–200 cm H₂O) during inflation/deflation of the bag, results in five physiological parameters of anal canal function. Five patients [three continent (two female) and two incontinent (both female)] were assessed with AAR and anal manometry. Results Anal acoustic reflectometry parameters were reduced in incontinent when compared with continent patients. Resting Opening Pressures (cmH₂O) were 27 and 16 in patients with faecal incontinence (FI) vs 44 and 72 in continent patients; Resting Opening Elastance (cmH₂O/mm²) was 0.88 and 1.08 in FI patients vs 1.65 and 1.34 in continent patients. The Resting Opening Pressure of a similarly aged continent male (55 cmH₂O) was greater than three of the females. During assessment of voluntary contraction (one FI female vs one continent female), Squeeze Opening Pressure (cmH₂O) was 31 vs 100 and Elastance (cmH₂O/mm²) 0.61 vs 2.07. Conclusion Anal acoustic reflectometry appears to be promising technique. Further work is in place to clarify whether it will be useful in clinical assessment of incontinent patients.     

Experiences with an artificial sphincter to establish anal continence in dogs

An implantable device for establishing urinary continence has been developed and has received FDA approval (AS 800, American Medical Systems, Inc.). The authors have applied this device to the control of anal continence in dogs. Fifteen mongrel dogs underwent either anal sphincter disruption (7) or abdominal-perineal resection (8). Such animals have bowel movements almost hourly. In each case, the device was implanted at the time of surgery. In dogs with working cuffs and disabled or absent sphincters, continence was maintained in seven out of 15 animals for periods of 4-8 hours. After cuff activation, intraluminal cuff pressures of 50-70 cm of water achieved continence for a period of 8 hours. In animals sacrificed from 1 to 12 months after implantation, the device was found to be well tolerated by the body with minimal fibrosis of the mucosa or muscularis of the bowel. Complications observed in the same four out of 15 animals during the study period were infection, device extrusion, and device malfunction. Infection resolved with local wound care and antibiotics (3/4) and the device was successfully replaced in two out of four instances of extrusion. With cuffs of proper size and pressure, this appliance may be effective in the control of human anal incontinence via the establishment of continent perineal colostomies following an abdominal-perineal resection.     

End-to-side nerve grafting of the tibial nerve to bridge a neuroma-in-continuity

Standard treatment for a neuroma-in-continuity with partial retained function is neurolysis with or without grafting. The present study tests the outcome of a novel partial nerve lesion bypassed with an end-to-side bridge graft, intended to increase the number of axons crossing the defect while not disturbing intact axons. An 8-mm portion of tibial nerve was resected in 20 rats. Three weeks later, half had the defect repaired with an end-to-side bridge allograft and perineurial windows; controls had only neurolysis. Recovery was evaluated using walking-track analysis, allodynia testing, muscle weight ratios, and histology at 8 weeks. No significant differences in motor or sensory functional recovery were noted between the two groups. Histology showed good axonal regeneration through the defect in all specimens. The experimental group also had regenerated axons in the bridge graft, but their maturity was less advanced, presumably due to delays in regeneration.     

A new minimally invasive technique for pudendal nerve stimulation1

Aim Pudendal nerve stimulation (PNS), which is an alternative to sacral nerve stimulation, requires neurophysiological confirmation of correct siting of the electrode. We describe a modification of the existing technique where placement is assisted by guidance to the ischial spine by a finger introduced per anum. Method Cadaveric dissection was carried out to confirm the accuracy of this new approach. The surface marking of the ischial spine is marked. A stimulating needle electrode inserted through a skin incision at this point, is advanced towards the ischial spine using a finger introduced per anum as a guide. Once effective stimulation of the pudendal nerve is confirmed by observed and palpated contraction of the anal musculature, a permanent stimulating electrode is inserted and the position confirmed by radiological screening. Results Using cadaveric studies, the correct surface markings for needle placement were confirmed. This technique was then applied successfully for in vivo insertion of the needle electrode in 20 patients with bowel dysfunction, with only one lead displacement occurring over a mean follow‐up period of 12 months. Conclusion Finger‐guided assistance of PNS electrode insertion is simple and reproducible without requiring neurophysiological confirmation of nerve stimulation to ensure correct lead location.     

桡神经-正中神经端侧吻合在桡神经长段缺损修复中的应用

交通、工矿事故等严重创伤和神经源性肿瘤切除等造成的桡神经缺损,由于缺乏有效的治疗手段多造成患肢功能障碍.令人可喜的是,相关基础研究表明,神经端侧吻合后正常的神经可发出侧支长入到损伤神经断端,并沿髓鞘生长重新恢复其传导功能,从而促进受损神经的功能恢复.此结果为端侧吻合修复周围神经缺损提供了理论支持.近年来的相关临床应用报道亦逐渐增多.自1999年1月至2007年12月之间,我们采用正中神经-桡神经端侧吻合修复桡神经长段缺损19例,现就疗效进行评价和分析.     

Long-term outcomes of a neo-anus with a pudendal nerve anastomosis contemporaneously reconstructed with an abdominoperineal excision of the rectum

BACKGROUND: Pudendal nerve innervation can transform a neo-sphincter into an original anal sphincter-like muscle in animal studies. The results led us to clinical trials of a neo-anus with a pudendal nerve anastomosis (NAPNA). No long-term results in a series have been reported. METHODS: From 1995 to 2003, a neo-anus was reconstructed by using an inferior portion of the gluteus maximum muscle with a pudendal nerve anastomosis contemporaneously with an abdominoperineal excision of the rectum (APER) in 19 patients (17 men, 2 women; median age, 62.0 years; range, 46-73) with low-lying malignancy. The long-term (<2 years) clinical results were evaluated. RESULTS: The neo-sphincter began contracting (n = 15) at 6.6 +/- 1.8 months after surgery; then the ileostomy was closed (n = 14) at 9.1 +/- 2.6 months. The long-term results were studied in 10 patients (40.9 +/- 14.1 months after ileostomy closure). All patients (100%) defecated at 4.8 +/- 2.6 times/day without irrigation. Pads were used every day in 9 patients (90%). The Cleveland Clinic Florida incontinence score was 12.2 +/- 3.3 points. No patients lost their occupation. Eight patients (80%) answered that their life with a NAPNA was better than with an ileostomy. The average World Health Organization Quality of Life-BREF in patients with NAPNAs was significantly better than that in those patients who underwent conventional APERs in our hospital (n = 27, 66.4 +/- 0.8 years old) ( P = .0402). Four patients (40%) experiencing the need to defecate got significantly better continence score (mean +/- SD). CONCLUSIONS: The sensitivity to recognize the need to defecate may be a key to success in NAPNAs. A NAPNA can be a practical option for selected patients wishing to avoid a stoma after an APER.     

Incompetence of the anal sphincter

The indications for and the results of treatment of 18 patients with sphincter ani incompetence are discussed. Sixteen patients had II and III degree incompetence. Fifteen patients were treated by operation, the late-term results were studied in 12, good functional results were achieved in 10 patients. Timely recognition of the disease and referring the patients to a proctologist facilitates the improvement of the results of treatment.     

Response of external urethral sphincter to high frequency biphasic electrical stimulation of pudendal nerve

PURPOSE: We optimized the axonal blocking effect of high frequency, biphasic stimulation on neurally evoked contractions of the external urethral sphincter (EUS) and further investigated the repeatability of the blocking effect during relatively long periods to evaluate any acute nerve damage. MATERIALS AND METHODS: Two stainless steel electrodes were positioned 5 to 10 mm apart on the decentralized pudendal nerve in alpha-chloralose anesthetized cats. The distal electrode was first tested at different frequencies (1 to 10 kHz) to search for the effective blocking frequency. At a fixed frequency (4, 6, 8 or 10 kHz) different stimulation intensities were then tested to evaluate their blocking effect. Sine waveform or biphasic pulses of a fixed pulse width were also tested. Finally, the proximal electrode was stimulated at 40 Hz for more than 40 minutes and during the same period the distal electrode (6 to 10 kHz) was repeatedly activated for 1-minute intervals in an attempt to block the EUS contraction induced by the proximal electrode. RESULTS: High frequency, biphasic stimulation (6 to 10 kHz) with a pulse width dependent on frequency is optimal to block EUS contractions compared with sine waveform or biphasic pulses of a fixed pulse width. Acute nerve damage caused by blocking stimulation was not observed on neurally evoked urethral pressure. CONCLUSIONS: Reversible block of EUS contractions by high frequency, biphasic stimulation of pudendal nerves is a potential method for suppressing detrusor-sphincter dyssynergia and improving voiding in spinal cord injured patients.     

Study of the anal sphincter in children

In dynamic study of the distal colon in children, the functional and electrophysiological methods of diagnosis developed and introduced by the authors: determination of anal reflex, electrosensitivity of the anal canal, musculocutaneous electrosensitivity, state of the genital nerve and its branches were used. The new methods of investigation permit to determine by the objective indices of the strength of the current and changes in pressure in the anal canal a state of the "sacral reflex arch" and neuromuscular apparatus of the external anal sphincter. In patients with constipation, a decrease in electrosensitivity and attenuation of reflex interconnection between the rectum and anal canal were noted.