End-to-side pudendal nerve anastomosis for the creation of a new reinforcing anal sphincter in dogs

Modified Urethral Graciloplasty Cross-Innervated by the Pudendal Nerve for Postprostatectomy Urinary Incontinence: Cadaveric Simulation Surgery and a Clinical Case Report

An artificial sphincter implanted in the bulbous urethra to treat severe postprostatectomy urinary incontinence is effective, but embedding-associated complications can occur. We assessed the feasibility, efficacy, and safety of urethral graciloplasty cross-innervated by the pudendal nerve. A simulation surgery on three male fresh cadavers was performed. Both ends of the gracilis muscle were isolated only on its vascular pedicle with proximal end of the obturator nerve severed and transferred to the perineum. We examined whether the gracilis muscle could be wrapped around the bulbous urethra and whether the obturator nerve was long enough to suture with the pudendal nerve. In addition, surgery was performed on a 71-year-old male patient with severe urinary incontinence. The postoperative 12-month outcomes were assessed using a 24-hour pad test and urodynamic study. In all cadaveric simulations, the gracilis muscles could be wrapped around the bulbous urethra in a γ-loop configuration. The length of the obturator nerve was sufficient for neurorrhaphy with the pudendal nerve. In the clinical case, the postoperative course was uneventful. The mean maximum urethral closure pressure and functional profile length increased from 40.7 to 70 cm H 2 O and from 40.1 to 45.3 mm, respectively. Although urinary incontinence was not completely cured, the patient was able to maintain urinary continence at night. Urethral graciloplasty cross-innervated by the pudendal nerve is effective in raising the urethral pressure and reducing urinary incontinence.

Comparison of static and dynamic symmetry between masseter-innervated and dual-innervated free multivector serratus anterior muscle transfer for complete facial paralysis

PURPOSE

In this study, facial symmetry was compared between the masseter-innervated and dual-innervated free multivector serratus anterior muscle transfer (FMSAMT) methods.

METHODS

Eighteen patients with unilateral complete facial paralysis underwent facial reanimation surgery between April 2006 and July 2019. The masseter-innervated FMSAMT group (Group M, n = 8) underwent end-to-end coaptation with the ipsilateral masseter nerve in one stage. The dual-innervated FMSAMT group (Group D, n = 10) underwent end-to-end coaptation with the masseter nerve and end-to-side coaptation with the contralateral facial nerve via cross-face nerve graft. They were further divided into the one-stage (Group D1, n = 5) and two-stage (Group D2, n = 5) subgroups. The durations of periods until the first visible muscle contraction with clenching, first spontaneous smile, and the completion of resting tone were evaluated. The possibility of a spontaneous smile and symmetry of the midline and horizontal deviation at rest and during voluntary smiling were compared between each group.

RESULTS

Groups M and D differed significantly in the possibility of a spontaneous smile and improvement rate of midline deviation and horizontal deviation at rest (p < 0.001, p < 0.001, and p = 0.001, respectively) but not in the improvement rate of midline and horizontal deviation during voluntary smiling. The duration of the period until the completion of resting tone was significantly shorter in Group D1 than in Group D2 (p = 0.048); however, the possibility of a spontaneous smile and the improvement rate of midline and horizontal deviation were not significantly different.

CONCLUSIONS

Dual-innervated FMSAMT was effective in guaranteeing a symmetrical resting tone, voluntary smiling, and reproducing a spontaneous smile.

Application of Bifurcated Semitendinosus Muscle Transposition for Treatment of Fecal Incontinence in Two Dogs

A 4-year-old mixed breed dog and a 19-year-old English cocker spaniel dog were evaluated for fecal incontinence. The second dog's fecal incontinence was associated with the anal mass. In both dogs, reconstruction of the external anal sphincter was required to gain fecal continence. Especially in the dog with an anal mass, the whole musculature involved in fecal continence was removed with the affected anorectum. Conventional surgical treatments for fecal incontinence have limitations in terms of muscle flap length and complexity of the surgical procedure. A modified surgical technique using the semitendinosus muscle was devised in the present study to overcome these limitations. The distal part of the semitendinosus muscle was bifurcated to make two muscle bundles, used to completely encircle the anorectum. These muscle bundles were sutured to the surrounding rectal muscle and the pelvic diaphragm to simulate the function of the external anal sphincter. Three months after surgery, both dogs showed significantly improved fecal continence without severe complications, such as infection, dehiscence, or lameness of the limb where the semitendinosus muscle was harvested. The outcomes of the two dogs supported the acceptability of the bifurcated muscle flap for anal sphincter augmentation. In addition, this report showed the possibility of more diverse applications of semitendinosus muscle in dogs.

Reconstruction of the Urethral Sphincter with Dynamic Graciloplasty in a Male Rabbit Model

INTRODUCTION

The use of artificial urinary sphincters can improve urinary incontinence after radical prostatectomies; however, complications can arise. We hypothesized that dynamic graciloplasty improves urethral sphincter reconstruction.

MATERIALS AND METHODS

Models of urethral sphincter muscle reconstruction were developed in 5 adult rabbits by wrapping the gracilis muscle flap around the urethra. Intra-urethral pressure was measured in each of the models before reconstruction (control), after reconstruction, and after electrical stimulation of the flap in reconstructed models (stimulated models).

RESULTS

The mean maximum urethral closure pressure was significantly greater in the reconstruction model (69.7 (66.5-115.8) mm Hg) than in the control model (39.2 (33.7-49.6) mm Hg). The mean integral of the urethral pressure and urethral length was also significantly greater in the reconstruction model than in the control model. Furthermore, sphincter tightening was enhanced by the electrical stimulation of the flap.

CONCLUSIONS

Our results support our hypothesis that the functional reconstruction of urethral sphincters using muscle flaps is promising for the treatment of urinary incontinence.

Use of a spiral rectal diaphragm technique to control anal sphincter incontinence in a cat

CASE DESCRIPTION

A 10-year-old castrated male domestic shorthair cat was examined for a mass involving the right anal sac region.

CLINICAL FINDINGS

The mass was diagnosed as a fibrosarcoma, and resulted in progressive tenesmus, requiring repeated resection.

TREATMENT AND OUTCOME

Surgical removal of the fibrosarcoma was performed on 4 occasions, including complete resection of the anal sphincter muscles and portions of the rectum. A perineal urethrostomy was required during the third surgical procedure secondary to tumor invasion of the preputial tissues. To reduce involuntary loss of feces, the remaining rectal wall was rotated approximately 225° prior to surgical closure during the second, third, and fourth surgical procedures. This procedure created a natural spiral diaphragm within the rectal lumen. The elastic spiral barrier reduced inadvertent fecal loss and facilitated fecal distention of the terminal portion of the colon, allowing the patient to anticipate the impending passage of feces and to use the litter tray on a daily basis.

CLINICAL RELEVANCE

With complete loss of the terminal portion of the rectum and anal sphincter muscles, spiraling the rectum created a deformable threshold barrier to reduce excessive loss of stool secondary to fecal incontinence. On the basis of the positive outcome in this patient, this novel technique may be a useful option to consider for the treatment of cats with loss of anal sphincter function.

End-to-side nerve repair: review of the literature and clinical indications

End-to-side (ETS) nerve repair, in which the distal stump of a transected nerve is coapted to the side of an uninjured donor nerve, has been suggested as a technique for repair of peripheral nerve injuries where the proximal nerve stump is unavailable or a significant nerve gap exists. Full review of the ETS literature suggests that sensory recovery after ETS repair results in some, but not robust, regeneration. Sensory axons will sprout without deliberate injury. However, motor axons only regenerate after deliberate nerve injury. Experimental and clinical experience with ETS neurorrhaphy has rendered mixed results. Continued research into ETS nerve repair is warranted. ETS techniques should not yet replace safer and more reliable techniques of nerve repair except when some, but not good, sensory recovery is appropriate and a deliberate injury to the donor motor nerve is made.

Motor neuron regeneration through end-to-side repairs is a function of donor nerve axotomy

BACKGROUND

Over the past decade, a growing body of literature has emerged supporting the use of end-to-side (terminolateral) neurorrhaphy for the treatment of selected peripheral nerve injuries. It remains unclear, however, whether injury to the donor nerve is necessary to achieve significant regeneration through such repairs.

METHODS

End-to-side repair was studied in a rodent model in which the terminal limb of a transected peroneal nerve was sutured to the lateral aspect of the tibial nerve. Twenty-eight Lewis rats were randomized to four groups of seven animals each corresponding to incrementally greater donor nerve injuries as follows: group 1, conventional end-to-side neurorrhaphy; group 2, end-to-side neurorrhaphy with proximal crush injury; group 3, end-to-side neurorrhaphy with neurotomy; and group 4, end-to-end repair of transected peroneal nerve (positive control).

RESULTS

At 12 weeks, retrograde labeling of cell bodies of the ventral horn demonstrated significant differences between experimental groups, with mean counts in group 4 (1237 +/- 171) > group 3 (522 +/- 204) > group 2 (210 +/- 132) > or = group 1 (126 +/- 146). This association between nerve injury and motor neuron counts was closely mirrored in quantitative assessments of peripheral nerve regeneration and normalized wet muscle masses.

CONCLUSIONS

These data support the hypothesis that donor nerve injury is a prerequisite for significant motor neuronal regeneration across end-to-side repairs. Motor neuron regeneration through end-to-side repairs is optimized by deliberate transection of donor nerve axons.

Anatomic bases of graciloplasty using end-to-side nerve pudendal anastomosis

The objective of this study was to evaluate the possibilities of reinnervation of the gracilis muscle, transposed around the anus, by the pudendal nerve using an end-to-side nerve anastomosis. This study was carried out in 14 cases (7 adult human cadavers bilaterally). The gracilis muscle and its vascular-nervous bundle have been dissected and the nerve innervating the gracilis muscle has been cut at its origin. The gracilis muscle, accompanied by its nerve, has then been transposed around the anus. The pudendal nerve has been dissected from its extrapelvic part. The reinnervation using an end-to-side nerve anastomosis has been considered as feasible when the proximal ending of the nerve of the gracilis was put into a tension-free contact with the extrapelvic part of the pudendal nerve. The extrapelvic part of the pudendal nerve has a common trunk in 12 cases. The width of the extrapelvic part of the pudendal nerve was 2.6+/-0.7 mm, range 1-3.5. The width of the proximal endings of the nerve innervating the gracilis muscle was 2.3+/-0.5 mm, range 2-3. The reinnervation of the gracilis muscle by the pudendal nerve has been possible in 14 cases. An average supplementary length of 17.4+/-15.4 mm was available (range 5-52). These results suggest an eventual practical aspect of this technique for the reconstruction of a functional sphincter using the gracilis muscle transposed around the anus.

Fecal incontinence: an up-to-date critical overview of surgical treatment options

BACKGROUND

Surgery is the last resort for patients suffering from severe fecal incontinence. The armamentarium of surgical options for this condition has increased impressively during the last decade. Nevertheless, this fact seems to make neither patients nor surgeons feel more comfortable. Treatment of fecal incontinence still remains a challenge to modern medicine due to many specific sides of this problem.

AIMS

This article gives an up-to-date overview of existing operative treatment options.

METHODS

An unbiased review of relevant literature was performed to assess the role of all methods of surgical treatment for fecal incontinence available nowadays.

RESULTS

Recent studies have shown poor late results after primary sphincter repair and low predictive value for most preoperative diagnostic tests. New surgical options such as artificial devices and electrically stimulated muscle transpositions are doomed by low success rates and unacceptably frequent complications. That is why current attention has focused on non- or minimally invasive therapies such as sacral nerve stimulation and temperature-controlled radio-frequency energy delivery to the anal canal. However, all these innovative techniques remain experimental till enough high-evidence data are gathered for their objective evaluation.

CONCLUSION

Careful and detailed preoperative assessment to exactly determine the etiology of incontinence and individual approach remain the cornerstones of surgical treatment of fecal incontinence nowadays.

[Reconstruction of the anus by the gracilis muscle reinnervated by the pudendal nerve. A preliminary anatomical study]

The aim of this study is to evaluate the possibilities of reinnervation of the gracilis muscle, transposed around the anus, by the pudendal nerve with an end-to-side nerve anastomosis.

METHODS

This study was carried out in 10 cases. The gracilis muscle and its vascular-nervous pedicle have been dissected. The nerve of the gracilis muscle has been cut at its origin. The gracilis muscle was transposed around the anus. The nerve of the gracilis muscle was transposed in the gluteal area. The pudendal nerve has been dissected from its extra-pelvic part. The reinnervation with an end-to-side nerve anastomosis has been considered as feasible when the proximal ending of the nerve of the gracilis was put into a tension free contact with the extra-pelvic part of the pudendal nerve.

RESULTS

The reinnervation of the gracilis muscle by the pudendal nerve has been possible in all cases. The extra-pelvic part of the pudendal nerve has a common trunk in 8 cases. The width of the extra-pelvic part of the pudendal nerve was 2.8 +/- 0.8 mm (1-3.5). The width of the proximal endings of the nerve innervating the gracilis muscle was 2.5 +/- 0.5 mm (2-3). After transposition of the nerve of the gracilis muscle in the gluteal area an average supplementary length of 20.9 +/- 16.8 mm was available (range 5-52).

CONCLUSIONS

These results suggest that a reconstruction of the anal sphincter with a gracilis muscle transposed around the anus and reinnervated by the pudendal nerve with end-to-side nerve anastomosis is possible.

Semitendinosus muscle transfer flap for external anal sphincter incompetence in a dog

A 5-year-old sexually intact female Yorkshire Terrier was referred with a history of fecal incontinence of at least 2 years and chronic intermittent colitis. The external anal sphincter to the left of the anus was intact; the external anal sphincter was not detectable to the right of the anus. To repair the defect, the semitendinosus muscle was isolated and severed 2 cm proximal to its insertion on the tibia. Care was taken to preserve the integrity of the vasculature and nerve supply in the proximal third of the muscle body. The body of the muscle was passed around the ventral and right aspects of the rectum; the cut end was secured with simple interrupted sutures dorsal to the levator ani and coccygeus muscles to simulate the external anal sphincter. After surgery, the dog could defecate normally. Absence of a portion of the external anal sphincter may be congenital or the result of anorectal trauma, rectal prolapse, severe perineal disease, or surgical resection. The use of a semitendinosus muscle flap for treatment of fecal incontinence secondary to sphincter incompetence in dogs may be a viable alternative to euthanasia.