A comparison of glue and a tube as an anastomotic agent to repair the divided buccal branch of the rat facial nerve

The best anastomotic agent to join nerve ends is controversial. This paper describes a controlled trial between a collagen tube wrap and a tissue glue to anastomose the rat facial nerve. There was no difference in the results using photographic, histological and electrophysiological techniques.     

Inhibition of motor nerve regeneration in a rabbit facial nerve model

OBJECTIVES/HYPOTHESIS: We hypothesized that intramuscular injection of vincristine into the upper lip selectively prevents reinnervation of the target muscle (quadratus labii superioris) after facial nerve transection. STUDY DESIGN: Prospective controlled experiment. METHODS: Transection injuries with primary neurorrhaphy were performed just proximal to the buccal and zygomatic branches of both facial nerves in 20 rabbits. The left (experimental) quadratus labii superioris muscle was injected with 200 microg vincristine 72 hours after injury; the right (control) side was injected with saline. Functional, electrophysiological and histological studies were performed 6 weeks after surgery. RESULTS: After 6 weeks, the control side had a mean axon count (distal buccal branch) of 1160, conduction velocity of 50.4 m/s, reduction of compound action potential amplitude of 44%, and functional index of 1.67 units. The experimental side had a mean axon count of 265, conduction velocity of 16.5 m/s, reduction of compound action potential amplitude of 88%, and a functional index of 0.176 units. All parameters were significantly reduced by vincristine blockade (P <.05). The zygomatic division (not exposed to vincristine) displayed a trend toward increased axon counts, but this was not statistically significant (P =.131). CONCLUSIONS: These results demonstrate that reinnervation of a selected muscle can be prevented by injection of vincristine. Enhanced reinnervation of adjacent muscle groups may also occur. Thus, nerve blockade by vincristine may be useful for the prevention of synkinesis.     

Cellular telephone use and risk of intratemporal facial nerve tumor

OBJECTIVES/HYPOTHESIS: Microwave radiation exposure from cellular telephone use has been implicated in the development of intracranial tumors. The intratemporal facial nerve (IFN) is exposed to higher levels of cellular telephone radiation than intracranial tissues. The purpose of the study was to determine whether cellular telephone use is associated with an increased risk of IFN tumors. STUDY DESIGN: Case-control using a structured telephone survey at an academic, tertiary-care referral center. METHODS: Patients with IFN tumors (n = 18) were case-matched with patients treated for acoustic neuroma (n = 51), rhinosinusitis (n = 72), and dysphonia or gastroesophageal reflux disease (n = 69). Risk of facial nerve tumorigenesis was compared by extent of cellular telephone use and other risk factors. RESULTS: The odds ratio of developing an IFN tumor was 0.6 (95% CI, 0.2-1.9) with any handheld cellular telephone use and 0.4 (95% CI, 0.1-2.1) with regular cellular telephone use. No factors were associated with an increased risk for IFN tumor development. CONCLUSIONS: Regular cellular telephone use does not appear to be associated with a higher risk of IFN tumor development. The short duration of widespread cellular telephone use precludes definite exclusion as a risk for IFN tumor development.     

Functional assessments of the rodent facial nerve: a synkinesis model

Objectives/Hypothesis: Rodent whisker movement has been used as a tool, after facial nerve manipulation, to quantify functional recovery. We have recently established a method to study functional correlates of aberrant regeneration of the facial nerve. Our objective was to establish normative parameters for both spontaneous and induced whisking and blinking behavior in a large group of normal rats. Study Design: Prospective animal study. Methods: Eighty animals underwent quantitative facial movement testing to measure simultaneous vibrissal movement and ocular closure for each side independently. Right and left C‐1 whisker positions were continuously recorded for 5‐minute sessions, and changes in infrared detection corresponding to eye closure were continuously recorded. Whisking and blinking were elicited by delivery of olfactory stimuli (10 s scented airflows) and corneal air puffs. Whisks were counted and analyzed, and eye closures were counted. Results: Whisking amplitude, velocity, and acceleration were consistent with literature values. Air puff delivery elicited an ipsilateral blink 99% of the time, a contralateral blink 18% of the time, and changes in or initiation of bilateral whisking 70% of the time. Olfactory stimulus delivery prompted a change in whisking behavior 83% of the time, and eye closure 20% of the time. Conclusions: This study establishes normative data for assessing cranial nerve VII‐controlled facial movement in four separate facial regions. We demonstrate the capability and tendency of animals to move their orbicularis oculi muscles independently of and simultaneously with their midfacial muscles. This model provides an excellent tool for the study of aberrant regeneration after facial nerve injury in the rodent.     

严重面瘫晚期面神经减压(或移植)术后的疗效观察

目的：探讨严重面瘫晚期手术后的效果。方法：对２８例严重面神经麻痹患者实行面神经减压或移植术。结果：２８例经随访０．５￣２年,完全恢复１４例（５０％）,大部分及部分恢复１２例（４２例）,未恢复２例（７．１％）。结论：严重面神经麻痹的患者,经保守治疗无效时若能及早施行神经减压或移植术是可达到良好效果的。     

The impact of malignant disease on facial nerve function after parotidectomy

OBJECTIVES/HYPOTHESIS: Studies of immediate postoperative facial nerve function following parotidectomy focus on benign disease. The purpose of the study was to compare facial nerve function with regard to benign or malignant disease in patients undergoing superficial parotidectomy. STUDY DESIGN: Retrospective cohort study of consecutive patients undergoing parotidectomy between 1995 to 2002. METHODS: House-Brackmann (HB) grade was recorded or assigned at the first postoperative visit. For patients with HB grade of III or greater, final resolution of facial nerve function was recorded. A chi2 analysis for independence was conducted between patients with HB grade of II or less and those with HB grade of III or greater and final pathological finding (benign vs. malignant disease). Mean and median times to resolution were determined for patients with HB grade of III or greater. Times to resolution for benign and malignant disease for those with HB grade of III or greater were compared (Kaplan-Meier method). RESULTS: Sixty-seven patients with benign disease and 52 with malignant disease were included. Ninety-four percent of patients with benign disease had HB grade of II or less at first postoperative visit (mean period, 11.6 d) compared with 76.9% of patients with malignant disease (mean period, 12.4 d). A chi2 analysis found this difference significant (chi2 = 7.36, P =.0067). Time to resolution for HB grade of III or greater was 253.8 days (+/-168.2 d) with median time of 229.5 days for benign disease and 182.4 days (+/-134.6 d) with median time of 138 days for malignant disease. Kaplan-Meier comparison found no significant differences in time to final resolution (P =.83). Three patients in the group with malignant disease had unresolved dysfunction (one patient for >2 y). CONCLUSIONS: Patients with benign disease have a greater chance of having HB grade of II or less immediately following surgery; however, whether the disease is benign or malignant, long-term final facial nerve function is the same.     

Chondromyxoid fibroma of the mastoid facial nerve canal mimicking a facial nerve schwannoma

Chondromyxoid fibroma of the skull base is a rare entity. Involvement of the temporal bone is particularly rare. We present an unusual case of progressive facial nerve paralysis with imaging and clinical findings most suggestive of a facial nerve schwannoma. The lesion was tubular in appearance, expanded the mastoid facial nerve canal, protruded out of the stylomastoid foramen, and enhanced homogeneously. The only unusual imaging feature was minor calcification within the tumor. Surgery revealed an irregular, cystic lesion. Pathology diagnosed a chondromyxoid fibroma involving the mastoid portion of the facial nerve canal, destroying the facial nerve. Laryngoscope, 2009     

Evaluation of the effect of methylprednisolone and N-acetylcystein on anastomotic degeneration and regeneraton of the facial nerve

Objectives

This study was aimed to determine the effects of methylprednisolone and N-acetylcystein on nerve healing in facial nerve anastomosis.

Methods

Thirty rabbits were randomly divided into 3 groups: Group I: control group received no medication; Group II: 50 mg/kg/day N-acetylcystein administered group; Group III, 1 mg/kg/day Methylprednisolone administered group. All rabbits underwent the same standard surgical procedure. A 1 mm segment was resected from the facial nerve and the free ends were anastomosed. The drugs were administered for two months twice a day. At the end of the second month, the anastomosed regions were dissected and examined under electron and light microscopy.

Results

Best nerve regeneration was observed in the N-acetylcystein and the control groups, respectively, whereas the weakest regeneration was determined in the methylprednisolone group. In the N-acetylcystein group, due to Schwann cell and glial cell proliferation, the increased regeneration rate was significantly higher compared to that of the methylprednisolone group. In the methylprednisolone group, no significant regeneration was observed despite the presence of degenerative signs of significant axonal withdrawal and an increase in the number of myelin debris.

Conclusion

In the present study, we demonstrated that methylprednisolone had no beneficial effect in nerve regeneration after facial nerve anastomosis. It further caused increased degeneration. On the contrary, N-acetylcystein administration significantly increased the extent of regeneration, whereas it decreased the extent of degeneration compared to the control and the methylprednisolone groups.     

Fluorescent retrograde axonal tracing of the facial nerve

OBJECTIVE: The objective of this study was to investigate retrograde fluorescent axonal labeling of motor nerves as an aid to surgical dissection in otolaryngology-head and neck surgery. METHODS: Cholera toxin B subunit conjugated to a fluorescent dye was injected into the facial musculature of New Zealand white rabbits. At variable time points after injection, the facial nerves were harvested and analyzed for fluorescence in the peripheral axon. RESULTS: All injected animals demonstrated axonal fluorescence. No animal demonstrated facial weakness. Fluorescence was detected a maximum of 20 mm from the distal end of the nerve. Time periods greater than 48 hours did not substantially increase transport distance. CONCLUSIONS: Cholera toxin B subunit fluorescent conjugates, when administered intramuscularly, reliably label the distal portion of the facial nerve. In vivo labeling of a motor nerve may have significant potential for identifying a nerve in surgery. This work represents a preliminary investigation into the adaptation of in vivo fluorescence techniques as an aid to surgical dissection. Further research to refine this technique should be supported.     

Evaluation of the systemic use of riluzole in post-traumatic facial nerve regeneration: experimental study in rabbits

Conclusions. Riluzole promoted increase and/or preservation of axon density in the animals treated with this drug as compared to the control group; it did not increase the mean diameter of facial nerve fibres as compared to the non-treated group; and it did not provide a better functional motor recovery than in the control group. Objective. Traumatic peripheral facial paralysis is a frequent affection. In incomplete nerve injuries, systemic drugs acting on regeneration may decrease the patient's period of morbidity. This study aimed to determine the effect of the drug riluzole on regeneration of the facial nerve of rabbits submitted to post-traumatic facial paralysis. Materials and methods. Eighteen rabbits were submitted to compression of the facial nerve and divided into control (A) and treated (B) groups. The animals were sacrificed 4 weeks after the injury and their nerves were studied regarding density of myelinated axons and measure of external axon diameters. Results. Partial functional recovery was observed within 2 weeks and complete recovery 5 weeks after injury. Mean neural density was 12 679.7 axons/mm² (SD±237.5) in group A, and 19 073.8 axons/mm² (SD±3549.9) in group B. Group A presented less than two-thirds the density of group B. There was no statistical difference in axon diameters between the studied groups.     

A morphological comparison of interposed freeze-thawed skeletal muscle autografts and interposed nerve autografts in the repair of the rat facial nerve

Freeze-thawed co-axially aligned skeletal muscle autografts provide new concept in peripheral nerve repair, and are being investigated in the repair of mixed motor/sensory nerves. These grafts provide an orientated matrix of large basement membrane tubes through which regenerating axons can migrate and reinnervate the distal nerve. Using the buccal branch of the rat facial nerve as a model, we compared five freeze-thawed muscle autografts with five interposed nerve autografts. Some 300 days after grafting, the morphology of the distal nerve was evaluated. When the two groups were assessed morphometrically, it was found that nerve grafts showed a small but significant improvement over muscle grafts in respect of indices of the fibre maturation.     

HRCT指导下人工耳蜗植入术面神经垂直段定位及保护

人工耳蜗植入手术最常用的是经乳突-面隐窝进路术式[1]。其关键步骤是打开位于面神经垂直段外侧的面隐窝,以充分暴露后鼓室,找到蜗窗。传统的术中面神经垂直段定位可根据砧骨所指示的方向至二腹肌嵴确定大致走形,但文献报道及临床手术中发现面神经变异情况并非罕见,常见的解剖变异有骨管裂缺、分支变异、行程异常等[2]。     

The efficacy of corticosteroids in postparotidectomy facial nerve paresis

OBJECTIVE: To determine whether the administration of perioperative corticosteroids is effective in ameliorating facial nerve paresis after parotidectomy. STUDY DESIGN: Prospective, randomized, double-blinded, placebo-controlled clinical trial at a university medical center. METHODS: Patients scheduled for parotidectomy and who met inclusion criteria were invited to enroll in the protocol. They were stratified according to the anticipated surgery (superficial or total parotidectomy) and then received one of two doses of dexamethasone (0.51 or 1.41 mg/kg divided into three doses) or placebo solution immediately preoperatively and then every 8 hours for 16 hours postoperatively. The facial nerve was graded for proportion (percentage) of function at each of the four major regions (frontal, orbital, midface and upper lip, and lower lip). The early postoperative function and rate of return of function were compared among the treatment groups. RESULTS: Forty-nine patients were enrolled and evaluated (18 in the control group, 16 receiving low-dose dexamethasone, and 15 receiving high-dose dexamethasone). No therapeutic advantage of dexamethasone treatment could be appreciated with respect to the degree of early postoperative nerve function (81.3% for control patients vs. 69.5% for dexamethasone-treated patients [ =.239]). Similarly, the median time to recovery of complete facial nerve function was 60 days in the control group and was 150 days in the dexamethasone-treated patients. CONCLUSIONS: Dexamethasone administration in patients undergoing parotidectomy is not justified. Despite the relatively modest risk profile of dexamethasone, we were unable to demonstrate any benefit in patients who were treated with either low-dose or high-dose steroids compared with placebo-treated patients in a randomized, controlled trial.     

Re-innervation of facial nerve territory using a composite hypoglossal nerve — muscle autograft — facial nerve bridge. An experimental model in sheep

The hypoglossal nerve has been used both entirely and in part to repair the facial nerve. Using the partial technique it may be difficult to obtain sufficient length and a free interposed graft is then required to extend the hypoglossal element. In six sheep the facial nerve was excised between its emergence from the stylomastoid foramen and its bifurcation in the parotid gland. The hypoglossal nerve was exposed and split longitudinally producing a limb which was reflected towards the distal stump of the facial nerve. This left a gap of 4-5 cm which was bridged with a freeze-thawed coaxially aligned skeletal muscle autograft. The sheep were examined at 8 months. Laser doppler blood-flow studies showed the blood-flow distal to the graft to be about 25% of that at an equivalent site on the normal side. Peak nerve conduction velocities were also reduced on the repaired side but stimulation of the proximal hypoglossal nerve was nevertheless capable of causing adequate contraction of both facial and tongue muscles. Histological comparison of the repaired facial nerves with equivalent sites on the normal side showed a reduction in mean axon and fibre diameters with normal myelin sheath thickness for the regenerated axon sizes. All of these features are to be expected in a regenerated nerve and are consistent with a good level of recovery of function.     

面神经畸形的影像表现

目的 介绍面神经畸形的影像学表现.方法 (1)采用螺旋CT进行颞骨多平面重组扫描,在轴位、冠状位、面神经层面进行观察,对面神经在中耳乳突的走行进行分析.(2)术中采用面神经监护仪确认畸形的面神经.结果 术前CT扫描可以事先观测到面神经的畸形,主要表现为无面神经骨管、面神经悬挂在中耳腔、面神经覆盖卵圆窗等.结论 术前...     

不同病因的周围性面神经麻痹外科治疗分析

目的:探讨不同病因的周围性面神经麻痹患者外科治疗的相关问题。方法:面神经麻痹患者37例,病因包括:贝尔面瘫5例,颞骨骨折20例,中耳乳突炎4例,内耳道面神经肿瘤3例,颅脑颌面手术损伤5例,针对不同病因采取相应外科治疗方式。结果:H-B分级Ⅰ～Ⅱ级恢复率:贝尔面瘫80%,颞骨骨折80%,中耳乳突炎100%;内耳道面神经肿瘤术后1例由Ⅳ级改善至Ⅲ级,2例术后无明显变化;颅脑颌面手术损伤行面-舌吻合者4例由Ⅴ级改善至Ⅲ级3例,Ⅳ级1例,行瘢痕切除+面神经探查减压术者1例由Ⅴ级改善至Ⅳ级。结论:针对不同病因导致的面神经麻痹,选择合适的手术治疗方法,可以取得良好效果。     

手术入路的选择在面神经保护中的作用

头皮冠状和耳屏切口因其切口位置隐蔽、面部不留瘢痕、术野显露充分,已成为颌面外科治疗面中部骨折、眶上缘骨折、眶外侧缘骨折、颧骨颧弓骨折的常用方法。2006—03—2012—06期间我院采用头皮冠状和耳屏切口进路结合微型钛板坚强内固定治疗68例颌面部骨折患者,现就如何防止该术式的常见并发症——面神经损伤的方法探讨如下。