Severe cranial nerve involvement in a patient with monoclonal anti-MAG/SGPG IgM antibody and localized hard palate amyloidosis

We report a patient with severe cranial polyneuropathy as well as sensory limb neuropathy. Biclonal serum IgM-kappa/IgM-lambda gammopathy was found and serum anti-myelin-associated glycoprotein (MAG)/sulfoglucuronyl paragloboside (SGPG) IgM antibody was also detected. Immunofluorescence analysis of a sural nerve biopsy specimen revealed binding of IgM and lambda-light chain on myelin sheaths. No amyloid deposition was detected in biopsied tissues except for the hard palate, suggesting that the amyloidosis was of the localized type and had no relation to the pathogenesis of cranial neuropathy. Our observations indicate that the anti-MAG/SGPG IgM antibody may be responsible for this patient's cranial polyneuropathy, which is a rare manifestation in anti-MAG/SGPG-associated neuropathy.

April 2002: 35-year-old healthy man with enlarging right parotid mass

The April 2002 Case of the Month (COM). 35-year-old healthy man developed a mass in the right parotid gland. A superifical parotidectomy was performed for a 4.5 x 1.5 x 1.5 cm mass involving the intraparotid facial nerve. Grossly the tumor was multinodular, smooth and yellow with normal surrounding salivary gland. Microscopically, the tumor showed expanding nodules composed of proliferating fibroblasts, Schwann cells, and perineural-like cells in a myxoid stroma. Normal peripheral nerve twigs were identified in the periphery of the tumor. There was no increased mitotic activity, cellularity or nuclear pleomorphism. S-100 immunohistochemical stain was positive. The tumor was diagnosed as a solitary plexiform neurofibroma. Plexiform neurofibromas in this area have been described in children with von Recklinghausen's disease or neurofibromatosis 1 (NF 1). Plexiform neurofibromas typically involve deep seated nerve trunks and is considered pathognomonic for NF 1. This unusual case represents a solitary variant of plexiform neurofibroma presenting as a parotid mass in an adult patient without a personal stigmata or family history of NF 1.

Bilateral conjugacy of movement initiation is retained at the eye but not at the mouth following long-term unilateral facial nerve palsy

Voluntary eyelid closure and smiling were studied in 11 normal subjects and 11 patients with long-term unilateral facial nerve palsy (FNP). The conjugacy of eyelid movements shown previously for blinks was maintained for voluntary eye closures in normal subjects, with movement onset being synchronous in both eyes. Bilateral onset synchrony of the sides of the mouth was also observed in smiling movements in normal subjects. In FNP patients, initiation of movement of the paretic and non-paretic eyelids was also synchronous, but markedly delayed relative to normal (by 136 ms = 32%). The initiation of bilateral movements at the mouth was similarly delayed, but in contrast to the eyes, it was not synchronous. Central neural processing in the FNP subjects was normal, however, since unilateral movements at the mouth were not delayed. The delays therefore point to considerable additional information processing needed for initiating bilateral facial movements after FNP. The maintenance of bilateral onset synchrony in eyelid closure and its loss in smiling following FNP is an important difference in the neural control of these facial regions. Bilateral conjugacy of eyelid movements is probably crucial for coordinating visual input and was achieved apparently without conscious effort on the part of the patients. Bilateral conjugacy of movements at the sides of the mouth may be less critical for normal function, although patients would very much like to achieve it in order to improve the appearance of their smile. Since the everyday frequency of eyelid movements is considerably greater than that of smiling, it is possible that the preserved eyelid conjugacy in these patients with long-term FNP is merely a product of greater experience. However, if synchrony of movement onset is found to be preserved in patients with acute FNP, then it would suggest that eyelid conjugacy has a privileged status in the neural organisation of the face.

Proximal conduction abnormality of the facial nerve in Miller Fisher syndrome: a study using transcranial magnetic stimulation

OBJECTIVE

To investigate facial nerve conduction, including its proximal segment, in Miller Fisher syndrome.

METHODS

Three patients underwent facial nerve conduction studies comprising stylomastoid electrical stimulation and transcranial magnetic stimulation at the entrance of the facial canal within the skull and of the cortical representation area. All 3 patients presented with acute bilateral complete ophthalmoplegia, areflexia, mild ataxia and varying other symptoms. One of the patients had bilateral facial palsy; the other two had normal facial innervation.

RESULTS

Findings suggestive of demyelination of the proximal segment of the facial nerve were observed in each of the 3 patients with Miller Fisher syndrome. The patient with bilateral facial palsy had absent responses to canalicular stimulation on both sides, while the other two showed increased temporal dispersion and prolonged latency in the proximal nerve segments.

CONCLUSIONS

Our findings suggest that the primary pathology of facial nerve lesion in Miller Fisher syndrome is demyelination and that it is localized to the proximal nerve segment. This is in line with the known vulnerability of proximal nerve segments (spinal roots) in other dysimmune demyelinating polyneuropathies.

SIGNIFICANCE

Facial nerve conduction study with magnetic stimulation can localize and detect even subclinical facial nerve dysfunction in patients with Miller Fisher syndrome. The technique may contribute to the diagnosis of this disease, where electrophysiologic findings are scanty.

Oral medicine -- update for the dental practitioner. Disorders of orofacial sensation and movement

This series provides an overview of current thinking in the more relevant areas of oral medicine for primary care practitioners, written by the authors while they were holding the Presidencies of the European Association for Oral Medicine and the British Society for Oral Medicine, respectively. A book containing additional material will be published. The series gives the detail necessary to assist the primary dental clinical team caring for patients with oral complaints that may be seen in general dental practice. Space precludes inclusion of illustrations of uncommon or rare disorders, or discussion of disorders affecting the hard tissues. Approaching the subject mainly by the symptomatic approach -- as it largely relates to the presenting complaint -- was considered to be a more helpful approach for GDPs rather than taking a diagnostic category approach. The clinical aspects of the relevant disorders are discussed, including a brief overview of the aetiology, detail on the clinical features and how the diagnosis is made. Guidance on management and when to refer is also provided, along with relevant websites which offer further detail.

Microvascular decompression for primary hemifacial spasm. Importance of intraoperative neurophysiological monitoring

There is considerable evidence that primary Hemi-Facial Spasm (HFS) is in almost all cases related to a vascular compression of the facial nerve at its Root Exit Zone (REZ) from brainstem, and that Micro-Vascular Decompression (MVD) constitutes its curative treatment. Clinical as well as electrophysiological features plead for mechanisms of the disease in structural lesions at the neural fibers (putatively: focal demyelination at origin of ephapses) and functional changes in the nuclear cells (hyperactivity of the facial nucleus). Lateral Spread Responses (LSRs) elicited by stimulation of the facial nerve branches testify of these electrophysiological perturbations. Monitoring LSRs during surgery is feasible; however the practical value of their intraoperative disappearance as control-test of an effective decompression remains controversial.MVD allows cure of the disease in most cases. Because the VIIIth nerve is at risk during surgery, intraoperative monitoring of Brainstem Auditory Evoked Potentials (BEAPs) is of value to reduce occurrence of hearing loss. Increase in latency of Peak V and decrease in amplitude of Peak I are warning-signals of an excessive stretching of the the cochlear nerve and impairment of the cochlear vascular supply, respectively.

Abnormal muscle response monitoring during microvascular decompression for hemifacial spasm

BACKGROUND

Several studies have investigated the relation between intraoperative abnormal muscle response (AMR) findings and postoperative results in patients undergoing microvascular decompression (MVD) for hemifacial spasm (HFS). However, there is some debate over the reliability of AMR as an indicator of postoperative outcome. We investigated whether AMR findings obtained during MVD reflect postoperative outcome in patients with HFS.

METHOD

Subjects were 60 HFS patients who underwent AMR monitoring during MVD. AMR recordings were obtained from the mentalis muscle by electrical stimulation of the temporal branch of the facial nerve and from the orbicularis oculi muscles by stimulation of the marginal mandibular branch. Surgical outcome was compared with AMR findings at the completion of MVD. Mean follow-up was 61 months.

FINDINGS

HFS resolved completely in 50 patients in whom AMR disappeared intraoperatively and in 5 patients in whom the AMR amplitude was decreased at the end of MVD. Four patients showed HFS at the final follow-up examination despite cessation or decrease of AMR during surgery. In 1 patient, preoperative AMR waveforms persisted throughout MVD, but the postoperative outcome was excellent.

CONCLUSIONS

Our findings suggest that intraoperative cessation or decreased amplitude of AMR at the end of surgery indicates a high likelihood of postoperative relief of HFS. We believe that intraoperative AMR monitoring is useful in MVD surgery for HFS.

Hemifacial spasm due to a tentorial paramedian meningioma: a case report

Hemifacial spasm (HFS) is a movement disorder characterised by involuntary paroxysmal facial movements that usually involve the orbicularis oculi and then spread to the other facial muscles. A microvascular compression and demyelination of the seventh nerve at its exit from the brain stem is considered to be the main aetiology of HFS. In addition to rare idiopathic (cryptogenetic) cases, others causes of HFS exist: tumours or vascular malformations have been described, of both the ipsilateral and contralateral cerebellopontine angle (CPA). However, space-occupying lesions in locations other than CPA are usually not thought to be responsible for HFS. Here we describe the case of a 45-year-old woman suffering from HFS, who dramatically improved after surgical removal of a tentorial paramedian meningioma.

Excitability of facial nucleus and related brain-stem reflexes in hemifacial spasm, post-facial palsy synkinesis and facial myokymia

OBJECTIVE

To compare the electrophysiological excitability characteristics of the facial nucleus and related structures in hemifacial spasm (HFS), post-facial palsy synkinesis (PFPS) and facial myokymia (FM).

METHODS

Facial F-waves, blink reflex recoveries and magnetically elicited silent periods (SP) were prospectively studied in 17 HFS, 17 PFPS, 8 FM cases and in 13 controls. Earlier unpublished observations on abnormal impulse transmission in 36 HFS and 29 PFPS cases were also included.

RESULTS

Enhanced F-waves were recorded on the symptomatic side in PFPS and HFS cases with a tendency to be more pronounced in PFPS. HFS and PFPS groups both showed an earlier blink reflex recovery, more prominent in PFPS patients, when stimulated and/or recorded on the symptomatic side. Unelicitable SPs were encountered after 24/39 stimulations in 5 patients with PFPS and rarely in HFS cases. Duration of elicitable SPs did not change remarkably. FM group had similar characteristics as normal controls in the 3 electrophysiological tests. Latencies of the lateral and synkinetic spread responses were significantly prolonged in the earlier PFPS group as compared to HFS. In two-point stimulation, both groups showed a greater latency shift in late responses, again more pronounced in PFPS.

CONCLUSIONS

PFPS and HFS cases had similar enhanced excitability patterns at the facial nucleus and related brain-stem structures, more marked on the symptomatic side and more obvious in the PFPS group. Findings elicited in the FM group were thought to be caused by asynchronous hyperactivity of facial motoneurons.

SIGNIFICANCE

In this comparative electrophysiological study, similar excitability patterns were found in HFS and PFPS groups, albeit with different intensities.

[Diagnostics of diseases and the function of the facial nerve]

The facial nerve has a complicated course from the brainstem to the periphery. It not only contains motor, but also secretory, sensory, and sensitive fibres. Thus, the functional measure of symptoms can be multi-faceted. The nerve is not directly accessible over an extensive distance because of its long course through the temporal bone. Therefore, diagnostics of nerve function and the differential diagnostics of its diseases could be a great challenge for the otolaryngologist. In this review, the most important methods for clinical examination, electrodiagnostics, and modern imaging techniques are critically surveyed. In addition, the significance of facial nerve monitoring for surgery in the cerebello-pontine angle, parotid surgery, and ear surgery is presented.

Pregnancy, patent foramen ovale and stroke: a case of pseudoperipheral facial palsy

The pathogenetic role of patent foramen ovale (PFO) in embolic stroke and its prognostic and therapeutic implications have not yet been clearly defined. Nonetheless, recent availability of non-invasive diagnostic techniques, such as the transcranial Doppler (TCD), has increased the frequency with which this anomaly is diagnosed. Here we present the case of a young woman affected by post-partum peripheral facial palsy: further exams disclosed not only its truncal-ischaemic origin, but also, significantly, the presence of PFO, as well as of anticardiolipin antibodies (acL). Given the increased embolic risk in labouring women, this study highlights the importance of searching for PFO in case of a stroke during pregnancy.

Contralateral botulinum injections improve drinking ability and facial symmetry in patients with facial paralysis

PURPOSE

To report two patients who experienced improved drinking ability as well as facial appearance with contralateral injection of botulinum toxin.

DESIGN

Retrospective case reports.

METHODS

Two patients were treated with botulinum toxin contralateral to the VIIth nerve palsy to improve drinking ability as well as facial asymmetry.

RESULTS

Botulinum toxin injections improved facial asymmetry as well as drinking ability in two patients with facial nerve palsies.

CONCLUSIONS

Contralateral botulinum toxin injections improved drinking ability in two patients with facial nerve palsy.

Surgical treatment of temporal bone chondroblastoma

BACKGROUND

Temporal bone chondroblastoma is a rare primary bone tumor that affects the floor of the middle cranial fossa. This tumor is known to have high recurrence rate after curettage, and wide resection is therefore recommended. However, the literature provides little information regarding long-term results after wide resection of temporal bone chondroblastoma.

METHODS

Four cases of surgically treated temporal bone chondroblastoma underwent long-term follow-up.

RESULTS

Four patients, 3 males and 1 female, with mean age of 34, were surgically treated at the neurosurgery department of Keio University Hospital. Two patients were treated for recurrent tumor and the other two for new disease. In all cases the tumor mainly involved the mandibular fossa with variable degree of infiltration into tympanic and petrous parts. The tumor was totally removed via zygomatic approach in all patients. In 3 patients, the mandibular condyle was removed to expose the tumor. These patients had temporary malocclusion and restricted motion postoperatively, which resolved within 3 to 12 months with conservative treatment. All patients have no recurrence to date with a mean follow-up period of 9 years.

CONCLUSION

Temporal bone chondroblastoma was removed totally with skull base surgical technique and no recurrence has occurred for 6 to 13 years postoperatively. We found that removal of the mandibular head does not cause permanent problems of mastication in patients with normal dentures.

Meningiomas of the cerebellopontine angle with extension into the internal auditory canal

OBJECT

Only some meningiomas of the cerebellopontine angle (CPA) extend into the internal auditory canal (IAC) or arise from its dural lining. The authors investigated cases of CPA tumors in which the meningioma was inserted in the dura mater in or at the ICA or infiltrated a cranial nerve.

METHODS

The authors reviewed patient charts including surgical and clinical records, intraoperative recordings of auditory evoked potentials, records of postoperative auditory examinations, and imaging studies. In a series of 421 patients harboring CPA meningiomas, 72 patients in whom there was dural involvement of the IAC were investigated. Total tumor resection was achieved in 86.1%. In 34 patients, opening of the IAC was required for total tumor removal; this procedure did not influence the patient functional outcome. Among patients with secondary involvement of the IAC, anatomical preservation of the facial and cochlear nerves was obtained in 94%, whereas among patients in whom the lesion arose from the dura in or at the IAC these values were 80 and 75%, respectively. Functional preservation of the seventh and eighth cranial nerves in cases of tumor extension within the IAC was 86 and 77%, respectively, whereas in cases in which the IAC was involved it was only 60%. In four of five patients in whom the tumor had its origin in the dura mater within the IAC, the seventh or eighth cranial nerve had to be sacrificed to achieve tumor removal because of the lesion's infiltrative behavior. Facial nerve reconstruction by sural grafting was performed in the same operative procedure.

CONCLUSIONS

Meningiomas of the CPA involving the IAC require special surgical management. Dural involvement of the IAC requires opening by using a diamond drill, a procedure that does not influence cranial nerve outcome. The increased rate of cranial nerve morbidity is attributed to the infiltrative behavior of these meningiomas. If affected nerve segments have to be sacrificed, immediate reconstruction enables satisfactory long-term results.

Specific pathophysiological functions of JNK isoforms in the brain

We have investigated the effect of JNK1 ko, JNK2 ko, JNK3 ko, JNK2+3 ko and c-JunAA mutation on neuronal survival in adult transgenic mice following ischemia, 6-hydroxydopamine induced neurotoxicity, axon transection and kainic acid induced excitotoxicity. Deletion of JNK isoforms indicated the compartment-specific expression of JNK isoforms with 46-kDa JNK1 as the main phosphorylated JNK isoform. Permanent occlusion of the MCA significantly enlarged the infarct area in JNK1 ko, which showed an increased expression of JNK3 in the penumbra. Survival of dopaminergic neurons in the substantia nigra compacta (SNC) following intrastriatal injection of 6-hydroxydopamine was transiently improved in JNK3 ko and c-JunAA mice after 7 days, but not 60 days. Following transection of the medial forebrain bundle, however, JNK3 ko conferred persisting neuroprotection of axotomised SNC neurons. None of the JNK ko and c-JunAA mutation affected the survival of facial motoneurons following peripheral axotomy when investigated after 90 days. Finally, we determined the impact of JNK ko on the survival of animals and the degeneration of hippocampal neurons following kainic acid. JNK3 ko mice were substantially resistant against and survived kainic acid-induced seizures. JNK3 ko and JNK1 ko showed a nonsignificant tendency for decreased or increased death of hippocampal neurons, respectively. Surprisingly, the deletion of a single JNK isoform did not attenuate the immunocytochemical signal of phosphorylated c-Jun irrespective on the experimental set-up. This comprehensive study provides novel insights into the context-dependent physiological and pathological functions of JNK isoforms.

A non-NF2 case of schwannomas of vestibular and trigeminal nerves with different genetic alterations of NF2 gene: case report

BACKGROUND

We report a patient with 2 separate schwannomas, a vestibular schwannoma and a trigeminal schwannoma, that were attached to each other and appeared to be a single tumor on imaging studies.

CASE DESCRIPTION

The patient, without any family history of neurofibromatosis, presented with a progressive hearing loss and mild left facial nerve palsy. Magnetic resonance imaging showed a snowman-like tumor in the left cerebellopontine angle. Surgical exposure revealed that the tumor consisted of 2 "kissing" schwannomas, a trigeminal and vestibular schwannoma. Molecular genetic analysis detected a 1-base pair deletion at exon 10 of the neurofibromatosis type 2 (NF2) gene in the trigeminal schwannoma, but not in the acoustic schwannoma. However, loss of heterozygosity at chromosome 22q (D22S282 and D22S929) was detected in both tumors, losing the same allele.

CONCLUSION

Multiple schwannomas in non-NF2 patients are extremely rare, and possible causes include simple coincidence or germline genetic alteration of adjacent gene on chromosome 22q, similar to the cause recently suggested in familial schwannomatosis. Although not always possible, molecular genetic examination may help to understand the underlying mechanism and would be warranted in such cases.

[Facial nerve tumours]

INTRODUCTION

Tumours originating in the facial nerve are extremely rare and their therapeutic approach requires the aid of specialists from a number of disciplines.

AIMS

Our aim was to analyse the cases treated in our centre over a five-year period.

PATIENTS AND METHODS

All the subjects submitted to surgical interventions to treat facial nerve tumours between January 1992 and December 1996 were evaluated retrospectively. Data recorded from all patients included age, sex, side affected, time prior to diagnosis, presenting symptom and symptoms observed at the time of diagnosis, previous history of disorders affecting the facial nerve and associated neurological symptoms. We also noted the location of the lesion, the surgical technique used, pathology findings, post-operative complications, length of post-operative stay in hospital, facial sequelae and surgical repair procedures used on the facial nerves involved in the intervention.

RESULTS

Six cases, with a mean age of 29 years (range: 16-46 years), were treated. Three of the patients were males (50%). Symptoms of the disease included facial palsy (4), neurosensory hypoacusis (1) and tinnitus (1). All six individuals (100%) had alterations affecting facial functioning in the course of the disease. The pathological diagnosis was schwannoma in four cases and hemangioma in the other two. Neural grafts were carried out in three patients and some kind of deficit was observed at the end of the follow-up in all the cases.

CONCLUSIONS

Facial nerve tumours are very infrequent. An early diagnosis is needed to diminish the facial sequelae following surgery performed to treat this clinical entity.

Waveform reliability with different recording electrode placement in facial electroneuronography

Electroneuronography (ENoG) has become a useful test for estimating the degree of facial nerve degeneration and predicting the prognosis in patients with facial nerve palsy. Test results may be influenced by several factors, including the electrode positions, skin resistance, stimulus magnitude, and possible artifacts. Regarding recording electrode positions, different groups have used two different locations, the nasolabial fold and nasal ala. The authors compared the waveforms recorded from these two locations in ENoG recordings to obtain the optimal waveform. Twenty healthy volunteers and 25 patients with unilateral facial nerve palsy were included in this study. Recordings were carried out with the recording electrode placed on the nasolabial fold, followed by placement on the nasal ala after 10 minutes. The following parameters were assessed: (1) the supramaximal threshold, (2) amplitude and shape of the waveform, (3) interside difference, and (4) test-retest variability. There was no significant difference in the amplitude of the waveform, interside difference, and test-retest variability between the two groups. However, when the electrode was placed on the nasal ala, the threshold was significantly lower, an ideal biphasic configuration was present in almost all cases (97.5 per cent) of normal volunteers and it was easier to identify the waveform. Placement of the recording electrode on the nasal ala would be the preferred method.

Prevalence of hemifacial spasm in Oslo, Norway

All patients seeking medical or surgical treatment for hemifacial spasm (HFS) in Oslo, Norway were identified in a service-based prevalence study. Only four hospital departments offered services for Oslo citizens with HFS. Fifty patients with HFS were treated. The total prevalence was 9.8 per 100,000. The prevalence increased with age to 39.7 among those older than 70 years. The use of antihypertensive drugs was significantly more common in HFS patients (36%) than in Oslo's general population.

Delayed Facial Nerve Paresis Following Acoustic Neuroma Resection and Postoperative Vasoactive Treatment

OBJECT

Delayed facial nerve paresis is a well known clinical phenomenon following acoustic neuroma surgery, typically occurring early during the postoperative course. The clinical course of the delayed facial nerve paresis and intraoperative electromyographic (EMG) signals were evaluated in a subgroup of patients who underwent vasoactive treatment for preservation of hearing and developed secondary deterioration after termination of treatment.

METHODS

Between 1990 and 2001 seven patients were identified who received vasoactive treatment for preservation of hearing and developed a delayed facial nerve paresis after termination of medication. Intraoperative facial nerve EMG activity was analyzed in six patients.

RESULTS

All patients developed a delayed facial nerve paresis between 2-5 days following termination of a 10 day treatment consisting of HES and nimodipine. Medication was re-initiated and the facial nerve paresis improved in all patients. In two patients intraoperative EMG signals revealed "A-trains" waveform patterns, which are highly suggestive for an immediate postoperative facial nerve paresis, whereas in four patients no pathognomonic EMG patterns could be recorded.

CONCLUSIONS

The delayed onset of a facial paresis following termination of vasoactive treatment points to a disturbed microcirculation of the nerve as the main pathophysiological feature. Two groups could be identified on the basis of intraoperative EMG activity. In one group with presence of "A-trains" medication apparently masked the onset of an immediate postoperative facial nerve deficit. Four patients without "A-trains" did not develop a typical delayed facial nerve paresis during vasoactive treatment, but thereafter. The time lag between termination of treatment and onset of a delayed palsy points to a protective effect due to improved microcirculation.

Analysis of taste disturbance before and after surgery in patients with vestibular schwannoma

OBJECT

The frequency, nature, and history of subjective taste disturbance before and after vestibular schwannoma (VS) surgery was investigated.

METHODS

Personal interviews were conducted in 108 patients with unilateral VS. Abnormalities in taste perception, either a significant reduction or a change in character, were experienced by 31 patients (28.7%) before surgery and by 37 (34.3%) after tumor removal. Preoperative taste disturbance worsened after surgery in five (16.1%) of the 31 patients, remained unchanged in eight (25.8%), improved in two (6.5%), and became normal in 16 (51.6%). Taste disturbance occurred postoperatively in 22 (28.6%) of 77 patients who had experienced no preoperative taste disturbance. The mean onset of the abnormality after resection was 1.1 +/- 1.7 months. Postoperative taste disturbance resolved in 24 of the 37 patients (64.9%) within 1 year after onset.

CONCLUSIONS

Subjective taste disturbance was common before and after VS removal, and the natural history of this condition was very variable in the pre- and postoperative periods. All patients who undergo surgery for VS should receive appropriate counseling about the likelihood and course of postoperative complications, including dysfunction of the sensory component of the facial nerve.

Motor conduction studies for prognostic assessment of obstetrical plexopathy

Early prognostic assessment of obstetrical brachial plexopathies (OBP) would facilitate rational selection of infants for brachial plexus surgery. We performed bilateral motor nerve conduction studies (MNCS) of axillary, musculocutaneous, radial, median, and ulnar nerves in 33 babies (age 10-60 days) with OBP in order to compare the amplitude of compound muscle action potentials (CMAPs). All babies were followed up until 6 months of age and the outcome was classified according to muscle strength and arm function. A CMAP amplitude reduction of more than 90%, compared to the unaffected side, predicted severe weakness of the corresponding root level (p < 0.01). Our results indicate that MNCS are a useful tool for very early prognostic assessment of OBP.

Facial Nerve Tumors

OBJECTIVE

To evaluate the surgical results in primary facial nerve (FN) tumors.

STUDY DESIGN

Retrospective case review.

SETTING

Private neuro-otological and skull-base tertiary referral center.

PATIENTS

Twenty eight consecutive patients affected by primary FN tumors that underwent surgery between December 1990 and February 2001.

INTERVENTIONS

The lesions were removed through a variety of surgical approaches, depending on tumor location and extension, as well as preoperative hearing. In one case, partial removal was performed.

MAIN OUTCOME MEASURES

Preoperative and postoperative FN function; preoperative and postoperative hearing level; and postoperative complications.

RESULTS

Based on histologic examination, tumors were distributed as follows: 18 schwannomas, six hemangiomas, two meningiomas, and two neurofibromas. Tumor location varied, with lesions distributed along the entire length of the nerve. Facial dysfunction was the most frequently recorded symptom, followed by hearing loss. Only five patients presented a preoperative grade 1 facial function. In the remaining patients of the group, the facial deficit lasted from 2 to 120 months, with a mean of 31.2 months. Anatomic integrity of the nerve was preserved in 4 cases; all others required a nerve interruption followed by reconstruction using a sural nerve graft. The complications recorded were: one cerebrospinal fluid leak, one postoperative retraction pocket, and one external auditory canal wall resorption requiring a surgical revision. Preoperative hearing remained unchanged in 8 out of the 15 patients in whom a hearing preservation procedure was attempted. In 25 cases, a follow-up of equal to or longer than 1 year was available, with the FN functions: two grade 1, eight grade 3, nine grade 4, three grade 5, and three grade 6. Patients with a preoperative deficit lasting more than 1 year demonstrated the worst recovery.

CONCLUSIONS

Primary FN tumors are rare lesions that include different histologic types. FN deficit represents the most common symptom, but it is not present in all cases. A conservative strategy is often adopted in presence of a normal preoperative facial function. When surgical management is selected, the decision on surgical approach to use depends on tumor size and location, as well as on preoperative hearing. FN integrity may be spared in rare occasions, but more frequently nerve reconstruction is required. Final facial function recovery is mainly dependent on the preoperative presence of FN deficit and its duration.