Intratemporal Grafting of the Facial Nerve following Lateral Skull Base Tumor Resection.

Intratemporal skull base tumors may invade the facial nerve in the horizontal (tympanic) or descending (vertical) segments, while parotid malignancies typically infiltrate the facial nerve at the stylomastoid foramen. This article will describe our results following intratemporal facial nerve grafting in 44 patients. Methods: This was a retrospective analysis of 44 patients requiring intratemporal facial nerve repair following lateral skull base tumor resection at our tertiary care, academic medical center. Results: Tumor histology included 17 parotid cancers, 13 temporal bone malignancies, 9 glomus tumors, 3 facial neuromas, and 2 endolymphatic sac tumors. The greater auricular nerve was used in 25 patients and the sural nerve was used in 19 cases. Forty patients were available for facial function assessment at 2 years. Using the House-Brackmann (H-B) recovery scale, the breakdown of patients by facial function was as follows: Grade I, 0 patients; Grade II, 4 patients; Grade III, 29 patients; Grade IV, 4 patients; Grade V, 3 patients; and Grade VI, 0 patients. Conclusions: Facial paralysis may occur from intrinsic or external lateral skull base invasion of the facial nerve. Intratemporal interposition grafting resulted in favorable facial function (H-B II or III) in 33 of the 40 (82.5%) patients at the 2-year assessment.     

Traumatic intratemporal facial nerve injury: management rationale for preservation of function

A retrospective review of 29 cases of intratemporal facial nerve injuries included 18 temporal bone fractures, 7 gunshot wounds, and 4 iatrogenic complications. Surgical exploration confirmed involvement of the fallopian canal in the perigeniculate region in 14 longitudinal and 3 transverse or mixed fractures of the petrous pyramid. Gunshot and iatrogenic injuries usually occurred within the tympanic and vertical segments of the facial canal and at the stylomastoid foramen. When hearing is salvageable, the middle fossa approach provides the best access to the perigeniculate region of the facial nerve. In the presence of severe sensorineural hearing loss, the transmastoid-translabyrinthine approach is the most appropriate for total facial nerve exploration. Grade I to III results can be anticipated in timely decompression of lesions caused by edema or intraneural hemorrhage. Undetectable at the time of surgery, stretch and compression injuries with disruption of the endoneural tubules often lead to suboptimal results. Moderate-to-severe dysfunction (Grade IV), with slight weakness and synkinesis, is the outcome to be expected from the use of interpositional grafts.     

Intraparotid facial nerve schwannoma: diagnosis and management.

OBJECTIVE: Facial nerve schwannomas are rare neoplasms that present a challenge in diagnosis and management. We sought to gain insight into the clinical presentation and its implications in management. STUDY DESIGN AND SETTING: A group of patients diagnosed with schwannoma was reviewed, with focus on tumor arising in the intraparotid region of the facial nerve. The patient population consisted of 3722 patients evaluated retrospectively over 38 years at the Shadyside Facial Paralysis Center, a tertiary referral center. From this population, 29 patients (18 women and 11 men) with the diagnosis of schwannoma were selected for review. RESULTS: Twenty-nine patients had facial nerve schwannoma. The average age at diagnosis was 44 years (range, 7 to 78 years). Eight patients had intraparotid involvement, with 5 having a palpable mass in the parotid. The duration of symptoms averaged 8.4 years overall, with intraparotid involvement averaging 10.9 years. The 8 intraparotid schwannomas had a mean House-Brackmann grade of 1.5/6 at initial presentation. Postoperative facial nerve function was only 4.4/6 for resected intraparotid schwannomas. CONCLUSIONS: Intraparotid facial nerve schwannomas are slow growing tumors, which are usually asymptomatic but can be painful. Schwannoma should be suspected if the facial nerve cannot be found intraoperatively or if the tumor is intimately associated with the facial nerve. In cases where schwannoma is suspected, biopsy is recommended, while complete resection is postponed to obtain imaging studies to evaluate the extent of disease and to discuss possible outcomes with the patient. SIGNIFICANCE: This article provides guidance for the appropriate management of intraparotid facial nerve schwannoma.     

Retrograde degeneration of the facial nerve after acute traction on parotid gland: an experimental investigation.

The parotid gland of the cat underwent traction for 2 hours (group A) or until the facial nerve was broken (group B). The cats survived postoperatively for 1 day, 2 weeks, 1 month, and 3 months, respectively. Each cat underwent an electroneurography session before they were killed. The facial nerve was harvested and underwent histologic examination. The present study demonstrated that, in group A, the degree of facial nerve degeneration indicated with evoked electroneurography was 100% at 1 day and 2 weeks and 85% and 35%, respectively, at 1 and 3 months after damage. In group B, no electric response was recorded, epineurium of extratemporal segment was broken. This study also showed that the pronounced alteration of the facial nerve following acute traction on the parotid gland was retrograde degeneration; it involved up to its internal acoustic meatus segment. Furthermore, pronounced damage was noted in its stylomastoid foramen and extratemporal segment.     

CT和MRI术前评估颞骨段面神经鞘瘤

目的探讨CT及MR检查术前评估颞骨段面神经鞘瘤的应用价值。方法回顾性分析9例经手术病理证实的颞骨段面神经鞘瘤的患者临床资料,9例患者均接受MR平扫及增强扫描,其中3例同时接受CT平扫及增强扫描。结果 9例面神经鞘瘤患者6例位于左侧,3例位于右侧,病变单独累及迷路段2例,鼓室段1例,乳突段1例;累及迷路段+鼓室段3例,鼓室段+乳突段2例。1例肿瘤与面神经可见分界,余8例均未见明显分界,2例可见乳突及外耳道软组织肿块。CT主要表现为面神经走形区边缘规则或不规则的软组织肿块,伴不同程度不规则或虫蚀状骨质破坏及面神经管增粗,部分可见骨质硬化;MRI表现为T1WI呈等信号,T2WI呈等或稍高信号的肿块影,增强扫描呈明显均匀或不均匀强化。结论 CT及MRI相互结合可准确地显示颞骨段面神经鞘瘤的位置和形态及周围情况,可作为面神经鞘瘤术前评估的首要检查方法。     

Intratemporal facial nerve hemangiomas

Facial nerve hemangiomas are benign vascular tumors that arise within the temporal bone and have a histologic appearance similar to both cavernous hemangiomas and vascular malformations. In contrast to facial nerve schwannomas, these are extraneural tumors that cause symptoms by compression and tend to produce deficits when very small in size. We report our experience at the House Ear Clinic with 34 patients having these nonglomus intratemporal vascular tumors. Hemangiomas arising in the internal auditory canal tend to produce a progressive sensorineural hearing loss and are demonstrated with magnetic resonance imaging (MRI), whereas those at the geniculate ganglion are usually first seen with facial nerve symptoms and may require high-resolution computerized tomography (CT) for detection. Facial electromyography is helpful in establishing the diagnosis. Because of their extraneural nature, early diagnosis can permit removal of the tumor with preservation of facial nerves in some patients.     

Surgical outcomes of lateral approach for jugular foramen schwannoma: postoperative facial nerve and lower cranial nerve functions

The lateral surgical approach to jugular foramen schwannomas (JFS) may result in complications such as temporary facial nerve palsy (FNP) and hearing loss due to the complicated anatomical location. Ten patients with JFS surgically treated by variable methods of lateral approach were retrospectively reviewed with emphasis on surgical methods, postoperative FNP, and lower cranial nerve status. Gross total removal of the tumors was achieved in eight patients. Facial nerves were rerouted at the first genu (1G) in six patients and at the second genu in four patients. FNP of House–Brackmann (HB) grade III or worse developed immediately postoperatively in six patients regardless of the extent of rerouting. The FNP of HB grade III persisted for more than a year in one patient managed with rerouting at 1G. Among the lower cranial nerves, the vagus nerve was most frequently paralyzed preoperatively and lower cranial nerve palsies were newly developed in two patients. The methods of the surgical approach to JFS can be modified depending on the size and location of tumors to reduce injury of the facial nerve and loss of hearing. Careful manipulation and caution are also required for short facial nerve rerouting as well as for long rerouting to avoid immediately postoperative FNP.     

Facial Nerve Schwannoma of the Cerebellopontine Angle: A Diagnostic Challenge

Facial nerve schwannomas are rare lesions that may involve any segment of the facial nerve. Because of their rarity and the lack of a consistent clinical and radiological pattern, facial nerve schwannomas located at the cerebellopontine angle (CPA) and internal auditory canal (IAC) represent a diagnostic and therapeutic challenge for clinicians. In this report, a case of a CPA/IAC facial nerve schwannoma is presented. Contemporary diagnosis and management of this rare lesion are analyzed.     

颈静脉孔及其周围区域肿瘤的显微手术治疗

目的 探讨颈静脉孔及其周围区域肿瘤的显微手术方法 和手术效果. 方法 对11例颈静脉孔区肿瘤行显微手术治疗,采用枕下乙状窦后进路2例,经颈静脉孔进路2例,颞下窝进路4例,乳突-颈联合进路3例. 结果 11例中全切除9例,次全切除2例;病理为神经鞘膜瘤4例,副神经节瘤4例,脑膜瘤1例,黏液软骨肉瘤1例,低分化鳞癌1例.术后并发脑脊液漏1例,经保守治疗痊愈,后组脑神经障碍加重2例,无手术死亡病例,术后随访8个月以上,术后听力较术前改善1例,不变6例,下降4例;9例术前无面瘫的患者,术后3例出现Ⅱ～Ⅲ级(House-Braekmann分级)面瘫,半年后恢复,2例术前有面瘫患者,术后1例改善,1例不变. 结论 根据肿瘤的性质、位置、大小、面神经功能、听力情况和后组脑神经功能,采用合适的手术进路和显微外科技术,能够充分显露肿瘤,较好地切除肿瘤,减少并发症.     

Intracanalicular and intratemporal facial nerve schwannomas

Facial nerve schwannomas can mimic acoustic neuromas. We report herein two cases: a purely intracanalicular and an intratemporal facial nerve tumor extending into the internal auditory canal and the cerebellopontine angle. These tumors have to be suspected in patient with small-size tumors presenting with facial paralysis. We advocate translabyrinthine or middle fossa approach to facilitate nerve anastomosis. The establishment of the correct properative diagnosis is difficult, but the patient must be warned about the impossibility of preserving the facial nerve in these tumors.     

Large facial nerve schwannomas without facial palsy: case reports and review of the literature

Although approximately 30% of facial nerve schwannoma cases present with no facial palsy, a large facial nerve schwannoma extending to the middle and posterior cranial fossa quite rarely presents without facial palsy. The authors encountered two patients with large facial nerve schwannoma who presented with only hearing impairment and no facial palsy. The first patient was a 64-year-old woman who presented with right auditory impairment without facial palsy. MR images demonstrated a dumbbell-shaped tumor in the cerebellopontine angle. Another patient, a 40-year-old woman, also presented with vertigo and right tinnitus without facial palsy. MR images demonstrated a huge tumor expanding into both the posterior cranial fossa and middle cranial fossa. In both cases, intraoperative findings confirmed that the tumors had grown from the facial nerve. Facial nerve schwannoma can be easily diagnosed if detailed neurological evaluations and appropriate neuroimagings are conducted. However, in spite of such huge tumoral size and expanding pattern, the facial nerve function was relatively preserved. Anatomical features of the facial schwannoma are discussed. A tumor extending to the middle and posterior cranial fossa should remind neurosurgeons to consider facial nerve schwannomas even in the absence of facial palsy.     

Intracanalicular and Intratemporal Facial Nerve Schwannomas

Facial nerve schwannomas can mimic acoustic neuromas. We report herein two cases: a purely intracanalicular and an intratemporal facial nerve tumor extending into the internal auditory canal and the cerebellopontine angle. These tumors have to be suspected in patient with small-size tumors presenting with facial paralysis. We advocate translabyrinthine or middle fossa approach to facilitate nerve anastomosis. The establishment of the correct properative diagnosis is difficult, but the patient must be warned about the impossibility of preserving the facial nerve in these tumors.     

Recovery of low-frequency sensorineural hearing loss following resection of a greater superficial petrosal nerve schwannoma. Case report

Facial nerve schwannomas can occur anywhere from the internal auditory canal to the parotid gland. Schwannomas arising from the greater superficial petrosal nerve are exceedingly rare. The authors report the case of a 63-year-old woman who presented with a selective low-frequency hearing loss of 3 weeks' duration. Neurological examination demonstrated a House-Brackmann Grade II facial paresis and asymmetrical hearing loss on the left side. Audiometric evaluation showed a significant loss of low-frequency hearing with a speech reception threshold (SRT) of 30 dB and a speech discrimination score (SDS) of 88% on the left side. Magnetic resonance imaging revealed a 2.4-cm enhancing left middle fossa mass. Near-complete resection was performed via a left temporal craniotomy. The tumor was located in the Glasscock triangle and had invaded the petrous bone overlying the cochlea. A very small piece of the tumor over the cochlea was left in order to preserve hearing. A postoperative audiogram showed significant improvement in the patient's hearing, with an SRT of 20 dB and an SDS of 100%. The histological findings were consistent with schwannoma. The patient experienced postoperative improvement of hearing function despite cochlear involvement, which has previously been reported as an unfavorable factor for postoperative hearing outcome in facial nerve schwannomas.     

Outcomes of Direct Facial-to-Hypoglossal Neurorrhaphy with Parotid Release

Lesions of the temporal bone and cerebellopontine angle and their management can result in facial nerve paralysis. When the nerve deficit is not amenable to primary end-to-end repair or interpositional grafting, nerve transposition can be used to accomplish the goals of restoring facial tone, symmetry, and voluntary movement. The most widely used nerve transposition is the hypoglossal-facial nerve anastamosis, of which there are several technical variations. Previously we described a technique of single end-to-side anastamosis using intratemporal facial nerve mobilization and parotid release. This study further characterizes the results of this technique with a larger patient cohort and longer-term follow-up. The design of this study is a retrospective chart review and the setting is an academic tertiary care referral center. Twenty-one patients with facial nerve paralysis from proximal nerve injury at the cerebellopontine angle underwent facial-hypoglossal neurorraphy with parotid release. Outcomes were assessed using the Repaired Facial Nerve Recovery Scale, questionnaires, and patient photographs. Of the 21 patients, 18 were successfully reinnervated to a score of a B or C on the recovery scale, which equates to good oral and ocular sphincter closure with minimal mass movement. The mean duration of paralysis between injury and repair was 12.1 months (range 0 to 36 months) with a mean follow-up of 55 months. There were no cases of hemiglossal atrophy, paralysis, or subjective dysfunction. Direct facial-hypoglossal neurorrhaphy with parotid release achieved a functional reinnervation and good clinical outcome in the majority of patients, with minimal lingual morbidity. This technique is a viable option for facial reanimation and should be strongly considered as a surgical option for the paralyzed face.     

A case of facial nerve neurinoma originated from the cerebellopontine angle portion

Facial nerve neurinomas are relatively rare and most of them appear at the vertical portion of the facial nerve. Facial nerve neurinoma originated from the cerebellopontine (c-p) angle portion is less frequently reported. A 51-year-old woman was admitted to our hospital complaining of severe headache and nausea. She had had dizziness and unsteady gait for the previous two weeks. She did not complain of hearing disturbance, but otological examination revealed sensorineural deafness. She had no facial palsy. Skull x-ray showed no erosion of the internal auditory canal. Plain CT-scan revealed a large, unenhanced, low-density mass in the right c-p angle cistern. At the time of the operation, this tumor originated from the right facial nerve. Histological diagnosis of this tumor was schwannoma. After the operation, right facial nerve palsy appeared but hardness of hearing was no worse than previously. This tumor seemed to be facial nerve neurinoma in the c-p angle cistern. To the present, 121 facial nerve neurinomas have been reported in the previous literature. Facial nerve neurinomas in the c-p angle cistern, however, have only been reported in 5 cases. The most frequent symptom of facial nerve neurinoma in the temporal bone is facial nerve palsy, but that of facial nerve neurinoma in the c-p angle cistern is hearing loss, as in an acoustic neurinoma. Preoperative diagnosis of facial neurinoma in the c-p angle cistern using neurological symptoms alone is difficult. Furthermore, differential diagnosis from acoustic neurinoma in the c-p angle cistern using only skull x-rays and CT-scanning is also difficult.(ABSTRACT TRUNCATED AT 250 WORDS)     

Radiosurgery as primary management for meningiomas extending into the internal auditory canal

Stereotactic radiosurgery is increasingly utilized as primary management for patients with skull base meningiomas. This study reviews the results of stereotactic radiosurgery for patients with meningiomas extending into the internal auditory canal (IAC) to determine the risk of facial weakness or hearing loss. From 1990 to 2002, 16 patients had radiosurgery for meningiomas extending into the IAC. The median patient age was 63 years. Ten patients had symptoms of vestibulocochlear nerve dysfunction before radiosurgery. The median tumor volume was 5.1 cm3; the median tumor extension into the IAC was 7 mm (range, 3-12). The median tumor margin dose was 15 Gy. The median follow-up was 36 months. Ten meningiomas (63%) decreased in size, and 6 tumors were unchanged. No patient developed facial weakness. One patient (6%) had worsened facial sensation. Three of 14 patients (21%) with either normal hearing clinically (n = 5) or documented Gardner-Robertson class 1-2 before radiosurgery (n = 9) had decreased hearing after radiosurgery. The 1-, 2- and 5-year actuarial incidences of hearing preservation were 93, 84 and 42%, respectively. Three patients (19%) had improved hearing after radiosurgery. One patient with class 2 hearing improved to class 1; 2 patients with no speech discrimination before radiosurgery (class 5) improved to a class 3 status following the procedure. The risk of facial weakness or hearing loss is low after radiosurgery for patients with meningiomas extending into the IAC. Radiosurgery is an excellent alternative to surgical excision for meningiomas in this location, especially if a subtotal resection is likely or a hearing-sacrificing operation such as a translabyrinthine approach is contemplated.     

Is the middle fossa approach the treatment of choice for intracanalicular vestibular schwannoma?

OBJECTIVES: To compare the 2 surgical techniques most commonly used during vestibular schwannoma (VS) surgery, i.e., the middle fossa (MF) and the retrosigmoid-transmeatal (RS-TM) routes, when hearing preservation is attempted. STUDY DESIGN: A longitudinal study of a series of consecutive patients operated on with the 2 techniques by the same surgeon was conducted. Selection criteria included tumor confined to the internal auditory canal (IAC) with a length ranging from 4 to 12 mm and hearing class A or B. Patients were alternately assigned to 1 of the 2 groups regardless of auditory class and distance of the tumor from the IAC fundus. Thirty-five subjects were operated on with the RS-TM technique and 35 via the MF route. RESULTS: No significant differences in auditory and facial nerve function results between the 2 techniques were observed. The RS-TM approach, however, showed better facial nerve results at discharge. VS size, IAC enlargement, and, particularly, the distance from the IAC fundus were found to influence the postoperative results more than the type of approach itself. CONCLUSIONS: The MF approach has been described as being the better technique for VS surgery in terms of auditory results. However, this claim lacks statistical substantiation because no prospective studies are to be found in the literature. The present longitudinal investigation shows that the MF approach does not afford any particular advantages over the RS-TM route in terms of auditory results in intracanalicular VS, with the exception of tumors reaching the IAC fundus.     

带耳大神经的胸锁乳突肌肌瓣在腮腺癌手术修复中的应用

目的探讨腮腺深叶癌根治手术切除后,面部凹陷畸形及面神经缺损进行功能性修复的新方法,并评价临床疗效。方法对12例腮腺深叶癌侵袭周围骨质的患者,采取开放面神经管,将癌瘤、腮腺、受累面神经及周围骨质(包括乳突、茎乳孔、茎突及下颌升支后缘)扩大切除,利用面神经管内段正常的神经干断端与胸锁乳突肌肌瓣相连的耳大神经进行吻合,同时利用胸锁乳突肌肌瓣填充凹陷畸形。结果开放面神经管利用耳大神经胸锁乳突肌肌瓣功能性修复的方法,9例腮腺区凹陷畸形明显恢复常态,2例因肿瘤复发再次手术切除留有明显凹陷畸形,1例因局部感染,组织液化,肌肉萎缩,出现凹陷。面神经功能完全恢复,恢复时间最短为12周,最长20周,平均163周。同时提高了肿瘤的局部控制率。结论开放面神经管腮腺癌根治术,用耳大神经-胸锁乳突肌肌瓣即时修复,既达到了面部凹陷畸形的整复,又实现了面神经的功能性修复,同时减少肿瘤的局部复发,符合功能外科修复的发展要求,是一种临床应用效果比较理想的方法。     

Correlation between auditory function and internal auditory canal pressure in patients with vestibular schwannomas

OBJECT: Hearing loss is the most common presenting symptom in patients who harbor a vestibular schwannoma (VS). Although mechanical injury to the cochlear nerve and vascular compromise of the auditory apparatus have been proposed, the exact mechanism of this hearing loss remains unclear. To test whether pressure on the cochlear nerve from tumor growth in the internal auditory canal (IAC) is responsible for this clinical finding, the authors prospectively evaluated intracanalicular pressure (ICaP) in patients with VS and correlated this with preoperative brainstem response. METHODS: In 40 consecutive patients undergoing a retrosigmoid-transmeatal approach for tumor excision, ICaP was measured by inserting a pressure microsensor into the IAC before any tumor manipulation. Pressure recordings were correlated with tumor size and preoperative auditory evoked potential (AEP) recordings. The ICaP, which varied widely among patients (range 0-45 mm Hg), was significantly elevated in most patients (median 16 mm Hg). Although these pressure measurements directly correlated to the extension of tumor into the IAC (p = 0.001), they did not correlate to total tumor size (p = 0.2). In 20 patients in whom baseline AEP recordings were available, the ICaP directly correlated to wave V latency (p = 0.0001), suggesting that pressure from tumor growth in the IAC may be responsible for hearing loss in these patients. CONCLUSIONS: Tumor growth into the IAC results in elevation of ICaP and may play a role in hearing loss in patients with VS. The relevance of these findings to the surgical treatment of these tumors is discussed.