Manual stimulation of the whisker pad after hypoglossal-facial anastomosis (HFA) using a Y-tube conduit does not improve recovery of whisking function.

Facial nerve injury is a common clinical trauma involving long-term functional deficits with facial asymmetry leading to associated psychological issues and social hardship. We have recently shown that repair by hypoglossal-facial or facial-facial nerve surgical end-to-end anastomosis and suture [hypoglossal-facial anastomosis (HFA) or facial-facial anastomosis (FFA)] results in collateral axonal branching, polyinnervation of neuromuscular junctions (NMJs) and poor function. We have also shown that another HFA repair procedure using an isogenic Y-tube (HFA + Y-tube) and involving a 10-mm gap reduces collateral axonal branching, but fails to reduce polyinnervation. Furthermore, we have previously demonstrated that manual stimulation (MS) of facial muscles after FFA or HFA reduces polyinnervation of NMJs and improves functional recovery. Here, we examined whether HFA + Y-tube and MS of the vibrissal muscles reduce polyinnervation and restore function. Isogenic Y-tubes were created using abdominal aortas. The proximal hypoglossal nerve was inserted into the long arm and sutured to its wall. The distal zygomatic and buccal facial nerve branches were inserted into the two short arms and likewise sutured to their walls. Manual stimulation involved gentle stroking of the vibrissal muscles by hand mimicking normal whisker movement. We evaluated vibrissal motor performance using video-based motion analysis, degree of collateral axonal branching using double retrograde labeling and the quality of NMJ reinnervation in target musculature using immunohistochemistry. MS after HFA + Y-tube reduced neither collateral branching, nor NMJ polyinnervation. Accordingly, it did not improve recovery of function. We conclude that application of MS after hypoglossal-facial nerve repair using an isogenic Y-tube is contraindicated: it does not lead to functional recovery but, rather, worsens it.

Hypoglossal-facial anastomosis (HFA) over a 10 mm gap bridged by a Y-tube-conduit enhances neurite regrowth and reduces collateral axonal branching at the lesion site.

PURPOSE: The outcome of severe peripheral nerve injuries requiring surgical repair (transection and suture) is usually poor. Recent work suggests that direct suture of nerves increases collagen production and provides unfavourable conditions for a proper axonal regrowth. We tested whether entubulation of the hypoglossal nerve into a Y-tube conduit connecting it with the zygomatic and buccal facial nerve branches would improve axonal pathfinding at the lesion site, quality of muscle reinnervation and recovery of vibrissal whisking. METHODS: For hypoglossal-facial anastomosis (HFA) over a Y-tube (HFA-Y-tube) the proximal stump of the hypoglossal nerve was entubulated and sutured into the long arm of a Y-tube (isogeneic abdominal aorta with its bifurcation). The zygomatic and buccal facial branches were entubulated and sutured to the short arms of the Y-tube. Restoration of vibrissal motor performance, degree of collateral axonal branching at the lesion site and quality of neuro-muscular junction (NMJ) reinnervation were compared to animals receiving HFA-Coaptation (no entubulation) after 4 months. RESULTS: HFA-Y-tube reduced collateral axonal branching. However it failed to reduce the proportion of polyinnervated NMJ and did not improve functional outcome when compared to HFA-Coaptation. CONCLUSION: Elimination of compression by tightly opposed nerve fragments improved axonal pathfinding. However, biometric analysis of vibrissae movements did not show positive effects suggesting that polyneuronal reinnervation - rather than collateral branching - may be the critical limiting factor. Since polyinnervation of muscle fibers is activity-dependent and can be manipulated, the present findings raise hopes that clinically feasible and effective therapies after HFA could be soon designed and tested.

Effect of FK506 administration after obturator nerve injury: a functional and ultrastructural study.

The frequency of obturator nerve damage due to pelvic diseases, fractures or gynecologic procedures is uncertain. In the present study, we investigated the effect of FK506, a potent macrolide antibiotic and immunosuppresant, on obturator nerve recovery at morphological and functional levels. Forty female Wistar rats were randomly divided into four groups (control, sham, FK506-treated, vehicle-treated). In half of animals (FK506-treated and vehicle-treated) an obturator nerve crush (30 seconds clamp) was created. In FK506-treated group FK506 administration (1 mg/kg/day, subcutaneously) was performed on each postoperative day. All the rats were functionally evaluated by pinch and adduction tests preoperatively and postoperatively at one, two, three and four weeks after nerve injury. On the 28th postoperative day obturator nerve samples were collected and analyzed qualitatively by light and electron microscopy. FK506 treatment resulted in dramatic improvement in nerve function and in the ultrastructure of nerve fibers suggesting its therapeutic potential in traumatic obturator nerve injury.

Angiolipoma located inside the obturator canal and supplied by the umbilical artery.

During dissection of the retropubic region of a 55-year-old female cadaver, we encountered an angiolipoma located inside the obturator canal which was connected to the wall of the urinary bladder by a fibrous cord. The angiolipoma was supplied by a branch originating from the umbilical artery. Microscopically the benign soft tissue tumor was characterized by lobules of mature adipocytes and densely distributed networks of small and larger blood vessels, thus resembling typical histological features of an angiolipoma. Both the uncommon location of the angiolipoma and the abnormal branch of the umbilical artery entering the obturator canal should be taken into account during surgical procedures in this region, such as for orthopedic pelvic procedures, hernia repair or bladder/urethra-related interventions (e.g. transobturator tape, tension-free vaginal tape, colposuspension).