Intracranial repair of interrupted facial nerve in course of operation for acoustic neurinoma by microsurgical technique

Facial Nerve Injury and Repair: A Practical Review for Cutaneous Surgery

BACKGROUND

The facial nerve and its branches are at risk of injury during dermatologic surgery. Few publications in the dermatologic literature discuss facial nerve injury and management.

OBJECTIVE

To review facial nerve injury and management, including static and dynamic repair techniques, and to review outcomes in facial nerve reconstruction.

METHODS

Two detailed literature reviews were performed using PubMed. First, articles reporting facial nerve injury and/or management in the dermatologic literature were identified. In addition, articles pertaining to outcomes in facial nerve reconstruction with a minimum of 20 patients were included.

RESULTS

Fifty-three articles reporting outcomes in facial nerve reconstruction were identified and consist of retrospective reviews and case series. Most patients achieve improvement in facial symmetry and movement with nerve repair.

CONCLUSION

Timing of facial nerve repair is an important consideration in management of facial nerve injury, with earlier repairs achieving better outcomes. Facial nerve repair does not result in normal facial movement, and improvements may require a year or more to be realized. Many options exist for facial nerve reconstruction, and patients with long-standing facial nerve injuries may still benefit from treatment.

Management of 1000 vestibular schwannomas (acoustic neuromas): the facial nerve--preservation and restitution of function

OBJECTIVE

Although the rate of reported facial nerve preservation after surgery for vestibular schwannomas continuously increases, facial nerve paresis or paralysis is a frequent postsurgical sequelae of major concern. The major goal of this study was to define criteria for the right indication, timing, and type of therapy for patients with palsies despite anatomic nerve continuity and those with loss of anatomic continuity.

METHODS

One thousand vestibular schwannomas were surgically treated at the Department of Neurosurgery at Nordstadt Hospital from 1978 to 1993. Of 979 cases of complete removal and 21 cases of deliberately partial removal, the facial nerve was anatomically preserved in 929 cases (93%). The rate of preservation is increasing, as is evidenced in the most recent cases, and preservation is supported by special electrophysiological monitoring. The facial nerve was anatomically severed in 60 cases (6%). It was anatomically lost in previous operations that were performed elsewhere in 11 cases (1%). In case of nerve discontinuity (42 cases), immediate nerve reconstruction by one of three available intracranial procedures (within the cerebellopontine angle, intracranial-intratemporal, intracranial-extracranial) was performed in the same surgical setting. In case of loss of the proximal facial nerve stump at the brain stem, early reanimation by combination with the hypoglossal nerve was achieved in most patients within weeks after tumor surgery. In a few patients with anatomic nerve continuity but absence of reinnervation for 10 to 12 months, a hypoglossal-facial combination was applied. All the patients with partial or with complete palsies were treated in a special follow-up program of regular controls and of modulation of physiotherapeutic treatment every 3 to 6 months.

RESULTS

In intracranial nerve reconstruction at the cerebellopontine angle, 61 to 70% of patients regained complete eye closure and an overall result equivalent to House-Brackmann Grade 3. Hypoglossal-facial reanimation led to Grade 3 in 79%. The duration between the onset of paralysis and the reconstructive procedure is decisive for the quality of the outcome. These data are discussed in view of other treatment options and certain parameters influencing outcome.

CONCLUSIONS

This management contains three major principles as follows: 1) preservation of facial nerve continuity in function by the aid of intraoperative monitoring, 2) early nerve reconstruction in case of lost continuity, and 3) scheduled follow-up program for all patients with incomplete or complete palsies.

Management of vestibular schwannomas (acoustic neuromas): auditory and facial nerve function after resection of 120 vestibular schwannomas in patients with neurofibromatosis 2

OBJECTIVE

Vestibular schwannomas (VSs) affect young patients with Neurofibromatosis 2 (NF-2) and cause very serious problems for hearing, facial expression, and brain stem function. Our objective was to determine a therapy concept for the right timing and indication of neurosurgical therapy.

METHODS

In 1000 consecutive VS resections, 120 tumors in 82 patients with NF-2 were surgically treated by the same surgeon (MS) at the Department of Neurosurgery at Nordstadt Hospital from 1978 to 1993. The mean age of the patients was 27.5 years. Sixty tumors were surgically treated in 41 male patients, and 60 tumors were surgically treated in 41 female patients. Bilateral tumor resection was performed in 38 patients (76 operations, after previous partial surgery in 15 cases elsewhere), and unilateral operations were performed in 44 patients, 5 of whom had undergone ipsi- or contralateral surgery that was performed elsewhere. The operative and clinical findings are evaluated and compared with the data of patients without NF-2.

RESULTS

In 105 cases, complete tumor resections were achieved. In 15 cases, deliberate subtotal resections were performed. These were for brain stem decompression in 4 cases and for hearing preservation in the last hearing ear in 11 cases, with successful preservation in 8 of the 11. Pre- and postoperative hearing rates were higher in male than in female patients (70% in male versus 65% in female patients before surgery and 40.5 versus 31%, respectively, after surgery). Hearing was preserved in 29 of 81 ears (36%). The rate of preservation was 24% in cases of large tumors and 57% in cases of small tumors (<30 mm). Twenty-one of 82 patients (26%) were bilaterally deaf before surgery. Twenty-five patients had uni- or bilateral hearing after surgery (i.e., 41 % of those with preoperative hearing or 30.5% of the whole group). Anatomic facial nerve preservation was achieved in 85%. The facial nerve was reconstructed intracranially at the cerebellopontine angle by sural grafting in 17 cases and by hypoglossal-facial reanimation in 5. Two deaths occurred 1 and 3 months postsurgically as a result of malignant tumor growth with brain stem dysfunction and respiratory problems. In summary, for patients with NF-2, the presentation ages are lower, tumor progression is faster, the chances of anatomic and functional nerve preservation are lower, the chances of good outcomes are best when surgery is performed early and when there is good preoperative hearing function, and the danger of sudden hearing loss is higher. The chances and danger often differ from side to side among individual patients.

CONCLUSION

The indication and the timing of tumor resections are in some respects different from normal VS handling and are dependent on the tumor extension and related necessity of brain stem decompression and on the auditory function. As an optimal goal, completeness of resection with functional cochlear nerve preservation is formulated, and as an acceptable compromise, subtotal microsurgical resection with functional cochlear nerve preservation in the last hearing ear is suggested.

Intracranial nerve repair: a review of experimental and clinical studies

With recent developments in neurosurgery and related disciplines, more aggressive approaches are being made for various lesions of the skull base, and, as a consequence, cranial nerves are more frequently damaged, which causes significant morbidity. The authors review experimental and clinical studies involving surgical repair of severed cranial nerves and provide evidence that some degree of functional regeneration occurs. Functional recovery after repair is mainly dependent on the preoperative function of the muscle-nerve unit and the morphological organization of the nerve; the more complex the organization, the lesser the degree of functional recovery. The beneficial effect of surgical repair on postoperative morbidity is outlined together with suggestions for future research.

Repair of the facial nerve in the cerebellopontine angle using freeze-thawed skeletal muscle autografts. An experimental surgical study in the sheep

Six adult blackface sheep underwent repair of the transected facial nerve in the cerebellopontine angle using short freeze-thawed muscle autografts. A typical facial palsy was observed on the side of the intervention immediately after operation. The sheep were allowed to recover for one year by which time clinical observation showed a complete recovery of the facial palsy in 5 sheep and a partial recovery in the remaining sheep. Under general anaesthesia function of the repaired VIIth nerve and the normal contralateral facial nerve were assessed using electrophysiological stimulating and recording techniques. These studies showed restoration of facial nerve continuity to have taken place with functional reinnervation of target facial muscles. Electrophysiological indices of nerve function were consistent with those expected after repair of any peripheral nerve. Morphometric study of the nerves after their removal showed structural changes which though quantitatively different from those of normal nerve were consistent with those seen in other sites and studies where nerves have been repaired. This technique is discussed as a possible treatment for facial nerves whose continuity is disrupted during the removal of cerebellopontine angle tumours.

Recovery of the sutured facial nerve after removal of acoustic neuroma in patients with neurofibromatosis-2

The authors compared the long-term recovery of sutured facial nerves after the removal of 8 neurofibromatosis-2 (NF2)-associated and 22 non-NF2 acoustic neuromas. The patients were from a series of 270 patients operated on for an acoustic neuroma between 1979 and 1989. The assessment was done with a modified House and Brackmann scale from video recordings. At least some facial movement or tone was achieved (Grade 5 or better) in all but three patients, but in none was the recovery excellent. The facial function, judged by the overall appearance in movement, recovered less in patients with NF2 (P = 0.048); a moderately good recovery (Grade 3 or better) was seen in one patient of eight with NF2, as compared with 13 of 22 with non-NF2. In conclusion, if the tumor cannot be peeled off easily from the facial nerve in patients with NF2, leaving a fragment of tumor behind is preferable to cutting and suturing the facial nerve.

Repair of facial nerve after removal of cerebellopontine angle tumors: a comparative study

The results of repair of 18 facial nerves were examined by means of a modified House-Brackmann grading system. Six were repaired by end-to-end anastomosis and 12 by nerve graft. The reliability of the simplified House-Brackmann grading system was also assessed, using the kappa statistic to analyze the agreement between pairs of observers who examined the function of 40 nerves in 37 patients. Facial nerves studied had been either preserved, repaired or grafted, or divided and treated by faciohypoglossal nerve anastomosis. One nerve was not treated. The grading system proved to be somewhat unreliable, with complete agreement between observers in only 25% of cases. Facial nerve repair produced a fair return of function in just under two-thirds of the cases. The ability of an examiner ignorant of the patient's history to assess from the end result how the nerve had been managed was also estimated. Observers showed little ability to decide correctly on the previous treatment of the nerve when the patient showed moderate dysfunction postoperatively. The implications of these findings for grading systems and for management of the facial nerve in acoustic nerve tumor surgery are discussed.