Electroneurography during facial nerve expansion

With the use of tissue-expansion techniques, it is possible to elongate the facial nerve without impairing its function. The rate of expansion is limited by ischemic events imposed by stretching of the nerve and by anatomic characteristics of the nerve segment. In this study, we used various electroneurography techniques to determine the first sign of facial dysfunction during expansion. The main objective of the study was to ascertain test-retest variability of electroneurography techniques. Facial nerves were expanded in 16 cats with the use of a tissue expander secured more deeply to the main trunk. We conducted electroneurography measurements with the use of surface electrodes, temporary needle electrodes, and permanently implanted electrodes. Technique-dependent variations encountered with the surface electrodes made this method unreliable. Using implanted electrodes, we noted gradual worsening of the compound-action potential amplitude with increasing expansion. During acute expansion, reduction in compound-action potential amplitude was correlated with clinically observed deterioration of facial-nerve function. In this study, electroneurography with implanted electrodes was found to be the most reliable predictor of the rate of successful facial nerve expansion. (Otolaryngol Head Neck Surg 1998;119:603-8.)     

Acoustic tumors: preoperative measurement and correlation with postoperative facial nerve function

The cases of 67 patients consecutively operated on for acoustic tumors are reported. Preoperative records consist of tumor size and the position of the fourth ventricle on computerized tomography (CT) scans. An analysis is made of the immediate postoperative and current function of the facial nerves. There is a statistically significant relationship between the number of weak or paralyzed seventh nerves and displacement of the fourth ventricle (P less than .05). It is now possible to accurately measure acoustic tumors on preoperative CT scans. The position of the fourth ventricle can also be clearly seen. The current standard of diagnosis and management of acoustic tumors should include a cursor measurement of tumor size on CT scan and a notation of the position of the fourth ventricle. Adoption of this method of reporting will permit meaningful evaluation of treatment for acoustic tumors. This analysis illustrates the importance of accurate measurements in reporting and evaluating surgical results.     

High resolution CT scan of temporal bone fractures: association of facial nerve paralysis with temporal bone fractures

This radiologic study analyzed high resolution computed tomographic (CT) scans of 22 patients with temporal bone fractures. There were 19 males and three females. Fifteen of 22 had clinical evidence of facial nerve injury ranging from mild paresis to complete paralysis. The high resolution CT scan analysis identified a characteristic fracture of the temporal bone in every patient with facial nerve injury. A high percentage of these fractures (68%) could be classified as mixed and did not fall into a longitudinal or transverse fracture category. The characteristic fracture extends from the petrotympanic fissure at the glenoid fossa to the anterior inferior aspect of the medial bony external auditory canal. It resumes at the superior aspect of the external auditory canal (scutum) extending laterally along the external canal wall. If the vector force of the fracture is projected medially, it will cross the facial nerve in its horizontal portion. Often, the evaluation of trauma patients with routine CT scans for central nervous system (CNS) (brain) evaluation is inadequate for evaluation of temporal bone fractures. A high resolution CT scan should be performed when clinical criteria warrant its use. It is recognized that the incidence of facial nerve injury may be higher in this select population.     

颞骨内面神经水平段的显微解剖

目的 研究颞骨内面神经水平段及其毗邻结构的显微解剖,为临床应用提供解剖学资料. 方法 通过模拟l临床经乳突入路的手术方法,分层解剖20个成人湿头颅标本(40侧颞骨),显露并观测颞骨内面神经水平段及其毗邻结构. 结果 面神经水平段的长度为[(8.85±1.01)(7.10～11.25)]mm、直径为[(1.88±0.65)(1.55～1.90)]mm;FN水平段与垂直段的夹角(向前)为[(115.5±6.89)(109.5～128.6)°;面神经水平段与鼓室天盖的夹角(向后)为[(28.5±3.66)(25.8～31.5)°;匙突至面神经水平段的垂直距离为[(1.89±0.58)(0.90～3.05)]mm;镫骨头至面神经水平段(垂直距离)为[(2.30±0.85)(1.97～3.11)]mm;锥曲段顶点到砧骨短脚尖的距离为[(2.55±0.21)(2.10～2.90)]mm;锥曲段顶点至外半规管隆突距离为[(2.86±0.31)(2.23～3.56)]mm;未发现面神经水平段有分支的或者移位的情况.面神经水平段的远段位于水平半归管隆突的前内侧.有2侧(2/40)水平段的远段位于外半规管隆突外侧0.89 mm和1.02 mm,占5%. 结论 膝状神经节、匙突、镫骨、鼓室天盖、水平半规管、砧骨是手术中确定FN水平段的重要标志.颞骨内面神经水平段与其毗邻结构的空间位置关系复杂,手术操作必须熟悉面神经水平段上述定位标志,以免损伤面神经.     

A reliable radiologic landmark for the facial nerve in axial temporal bone computed tomography scans.

OBJECTIVE: We sought to test the reliability of a radiologic marker in identifying the vertical portion of the facial nerve in axial computed tomography (CT) temporal bone scans. STUDY DESIGN AND SETTING: At a tertiary care academic center, we used, with a random sample of 25 CT scans, a marker (the "B-line") to identify the facial nerve. The variations in distance from this marker to the facial nerve were measured. RESULTS: This marker, which consists of a tangent line extrapolated from the posterior border of the basal turn of the cochlea, fell within 1 mm of the facial nerve on average. The average distance from the midpoint of the posterior border of the basal turn of the cochlea to the facial nerve was 11 +/- 1 mm. CONCLUSION: This is a very reliable marker for the vertical portion of the facial nerve. SIGNIFICANCE: This marker can be used to rapidly find the facial nerve, even in diseased or postsurgical temporal bones.     

Quantitative morphology of facial nerve based on three-dimensional reconstruction of temporal bone.

OBJECTIVE: To investigate an effective method of quantitative analysis of the facial nerve and its adjacent structures on the basis of three-dimensional (3D) CT image reconstruction of the temporal bone. METHODS: The inner structures of the temporal bone from CT images of 34 healthy adults were reconstructed. Precise measurement of the facial nerve and its adjacent structures were accomplished by using Able Software 3D-DOCTOR. RESULTS: 3D images of temporal bone structures, including facial nerve, tympanic annulus, cochleariform process, cochlea, semicircular canals, jugular fossa, and carotid artery, were reconstructed. Quantitative data of the facial nerve and its adjacent structures were analyzed, especially the detailed spatial relationships between the facial nerve and the surface of the mastoid process or tympanomastoid fissure. CONCLUSION: 3D reconstruction of CT images clearly displayed the detailed structures of the temporal bone. Quantitative data of the facial nerve and its adjacent structures are very useful for temporal bone surgery.     

Primary facial nerve tumors within the skull

In a series of 527 cerebellopontine angle tumors, there were 416 cases of acoustic nerve tumors and 14 cases of primary tumor of the facial nerve in the petrous bone or intracranial cavity. Six additional patients were presumed to have facial tumors, although they were not operated on. Of the 14 verified facial nerve tumors, all but two were neurinomas and 11 had important intracranial extensions into the middle and/or the posterior fossa. In most of these 14 cases, surgical removal was performed via the translabyrinthine route, which is advantageous in that it displays the characteristic relationship of the tumor to the facial nerve, and facilitates nerve repair. The clinical and radiological features of these facial nerve lesions are discussed and also the indications for surgical treatment which, as the unoperated cases illustrate, is not always necessary.     

Reconstruction strategy for temporal bone and lateral facial defects

Large or recurrent tumors of the auricular and parotid areas sometimes require resections involving the temporal bone and adjacent structures, including the facial nerve, the auditory apparatus, ascending ramus of the mandible, and the temporomandibular joint. At times, these resections can include the skull and even the underlying dura. Although these massive resections can provide good palliation and sometimes cure for these advanced patients, incumbent on the strategy for this treatment is a reliable one-stage technique for repair of the resultant defect. We have found the use of free-tissue transfer and the pectoralis muscle flap to be useful in the reconstruction of these defects. The pectoralis muscle flap is used when the defect is at or inferior to the external auditory meatus. More cephalad lesions require free-tissue transfer; for small surface area defects, the free scapular flap has been found to be useful, whereas for larger surface area defects, the free latissimus muscle flap with overlying skin graft has been used with good success. This paper is a report of our experience with this strategy in 14 patients. Our results are discussed and 3 patients are presented.     

Prediction of facial nerve function after surgery for cerebellopontine angle tumors: use of a facial nerve stimulator and monitor

A series of 18 patients undergoing surgery for cerebellopontine angle tumors is reported. Patients were grouped according to size of tumor (0 to 2.5 cm, 11 cases; more than 2.5 cm, 7 cases). In all, the facial nerve was identified and conductance assessed by monitoring the facial electromyographic response to facial nerve stimulation. Postoperative facial nerve function was graded clinically after 3 months according to the House scale. Tumor removal was complete in all cases. In patients with tumors up to 2.5 cm the facial nerve was intact to visual inspection at the end of the procedure in all but one, where partial division was evident. In this group intraoperative facial nerve stimulation indicated electrical integrity in 8 of the 11 cases, all of which regained good facial nerve function postoperatively (House grades I and II). Nerve conduction was lost during the operation in the remaining three patients with small tumors; two subsequently developed a moderately severe (grade IV) dysfunction and the third, a total paralysis (grade VI). In the large (more than 2.5 cm) tumor group the facial nerve was anatomically intact in five of the seven cases, partially divided in one, and completely sectioned in the remaining case. Facial nerve stimulation indicated functional integrity in three patients, two of whom developed moderate (grade III) and the third a severe (grade V) dysfunction. In the other four cases nerve function could not be detected at operation; three of these developed a moderate facial nerve dysfunction (grade III/IV) and the final case a complete paralysis (grade VI). Intraoperative facial nerve monitoring appeared to predict eventual facial function accurately in the small tumor group, but did not predict facial nerve recovery reliably following surgery for larger tumors.     

Endosonography in preoperative assessment of rectal tumors

Together with digital examination and rectoscopy, the endorectal ultrasound is of great value in the preoperative diagnostics of rectal carcinoma. In 90% of these patients it is possible to determine the depth of infiltration preoperatively. At the same time assessment of lymph node involvement can be made with a sensitivity and specificity of 78%. Thus, endorectal ultrasound gives decisive criteria for the therapeutic plan. Furthermore, endorectal ultrasound represents a fitting instrument for the postoperative follow-up of patients with anterior resection of the rectum. Intramural as well as extrarectal sited recurrences of the tumor can be detected. Whether endosonography will have an influence on the prognosis of rectal carcinoma, remains to be seen.     

面神经分支在颞区的显微解剖学研究

目的 明确面神经在颞区的分布层次和范围，指导面部年轻化手术的操作入路。方法 12具(24侧)成人尸头标本，于5倍光学显微镜下行颞区的解剖观察。结果 颞区包含面神经的颞支和颧支：由面神经的上支分出，出腮腺上缘，颞支发出3～8个分支、颧支2～4个分支，行于颞浅筋膜深面。颞支越过颧弓至颞区，分布于额肌、眼轮匝肌、皱眉肌和耳周围肌等组织，主导其运动；颧支由腮腺上缘向前上方越过颧弓至外眦，支配眼轮匝肌和颧肌的运动；两支之间以及与眼神经的眶上神经和泪腺神经之间．都有交通支。结论 面神经的颞支和颧支分布在颞浅筋膜的深面和颞深筋膜的浅层之间的组织内，支配额部、眼周和耳部的表情肌运动；面部年轻化手术在分离颞区时．应避免在此层进行。     

Hypoglossal-facial nerve anastomosis for facial nerve palsy following surgery for cerebellopontine angle tumors.

Hypoglossal-facial nerve anastomosis is one of the procedures frequently performed to restore function after facial palsy secondary to surgery for removal of cerebellopontine angle tumors. The published results of hypoglossal-facial nerve anastomosis have been variable, and there are still questions about the indications, timing, and surgical techniques for this procedure. The goals of the present retrospective analysis of 22 cases of hypoglossal-facial nerve anastomosis were to assess the extent of the functional recovery and to analyze the factors affecting this recovery. The 22 cases of complete facial palsy were gleaned from a series of 245 cases of cerebellopontine angle tumors treated surgically by one of the authors. Twenty patients had an acoustic neuroma (average size 3.5 cm), one patient had a petrous meningioma, and one patient had a facial neuroma. The average age of the patients was 47.3 years (range 19 to 69 years). The average interval from tumor surgery to hypoglossal-facial nerve anastomosis was 6.4 months (range 12 days to 17 months), and the average follow-up period after the procedure was 65 months. The results were graded as good, fair, poor, or failure according to a new method of classifying facial nerve function after hypoglossal-facial nerve anastomosis. The results were good in 14 cases (63.6%), fair in three (13.6%), and poor in four (18.2%); one (4.5%) was a failure. Good and fair results occurred with higher frequency in younger patients who were operated on within shorter intervals, although these relationships were not statistically significant. There were no surgical complications. Good or fair results were achieved in 17 (77.3%) of the 22 cases, and thus hypoglossal-facial nerve anastomosis is considered an effective procedure for most patients with facial palsy after surgery for cerebellopontine angle tumors.