Stereotactic radiosurgery for hypoglossal schwannoma

Hypoglossal schwannomas (HS) are extremely rare neoplasms. Surgical resection has historically been the treatment of choice but carries a significant risk of postoperative neurological deficits and mortality. Stereotactic radiosurgery (SRS) is a minimally invasive approach that may afford long-term tumour growth. However, literature to determine the safety and effectiveness of SRS in the treatment of HS is scarce. We report on a patient who presented with progressive headache and dysphagia as well as tongue deviation to the left, due to a space-occupying lesion, consistent on brain MRI with a left HS. Primary SRS using a prescription dose of 12 Gy in a single fraction was used to treat the tumour without complications. By last follow-up, the tumour regressed, and the patient's symptoms improved. Our case shows that radiosurgery can be safe and effective for the management of HS.

Single-stage total resection of giant dumbbell-shaped hypoglossal schwannoma: a case report

Extensive large dumbbell-shaped hypoglossal schwannoma is extremely rare, and total resection is nearly impossible. We present a case of a 61-year-old male with a giant-size hypoglossal schwannoma with moderate tongue atrophy. The tumor extended from the enlarged hypoglossal canal to the brainstem intradurally and the high cervical region extradurally. Through the extreme lateral infrajugular transcondylar (ELITE) skull base approach, the tumor was totally removed in a single-stage operation. Single-stage total resection is feasible by an experienced skull base team utilizing transcondylar skull base techniques and high cervical dissection.

Hypoglossal nerve tumor: A rare primary extracranial meningioma of the neck

We report a case of primary extracranial meningioma arising from the hypoglossal nerve in a 54-year-old man who presented with a 9-month history of hoarseness and progressive dysphagia. He had also noticed that his tongue was deviated to the left and, as a result, he was having difficulty pronouncing words. Examination revealed fasciculation and muscle wasting on the left side of the tongue. Other cranial nerve functions were normal. Contrast-enhanced computed tomography detected a heterogeneous mass that had arisen above the bifurcation of the left common carotid artery and had extended to near the skull base. Transcervical excision of the tumor was performed, and histopathology identified it as a meningioma of the hypoglossal nerve. The patient recovered uneventfully, and he was without recurrence at more than 2 years of follow-up. A primary extracranial meningioma is extremely rare, and its presentation may be subtle. A thorough investigation is necessary to avoid fatal compressive symptoms.

Surgical treatment of dumbbell-shaped hypoglossal schwannoma via a pure endoscopic transoral approach

BACKGROUND

Dumbbell-shaped hypoglossal schwannomas with intradural and extradural extension are extremely rare, and complete removal of these tumors is very difficult. This report describes such lesions in three patients that were completely removed via a purely endoscopic transoral approach.

METHOD

Three patients with intradural and extradural growth hypoglossal schwannomas (three women, aged 16, 42 and 43 years) were treated by direct surgery via a purely endoscopic transoral approach to the posterior fossa.

RESULTS

In this series, radical resections of the dumbbell-shaped hypoglossal schwannomas were achieved in all three patients via a purely endoscopic transoral approach without creating additional cranial nerve deficits but temporary left vagus palsy in one case and a temporary left hypoglossal palsy in one case. The postoperative vagus and hypoglossal palsy had recovered in 3 months after surgery. No patient experienced complications such as postoperative cerebrospinal fluid leak, meningitis and cerebrovascular evidence. At the time of this review, the preoperative lingual motor function and muscular bulk had recovered but hemiatrophy of the tongue was still detectable. The preoperative vagus palsy had recovered by the 10th day after surgery. The hearing loss and facial palsy before surgery had completely recovered in 3 months postoperatively. No patient in our series has experienced a recurrence for the follow-up period (3-11 months).

CONCLUSIONS

Dumbbell-shaped hypoglossal schwannomas tend to cause lower cranial nerve deficits, facial paralysis and hearing loss. With appropriate preoperative evaluation and careful planning of the perioperative period, complete tumor resection can be achieved via the purely endoscopic transoral approach. The endoscopic transoral approach is an effectice choice for management of dumbbell-shaped hypoglossal schwannomas.

Giant craniocervical junction schwannoma involving the hypoglossal nerve: case report

The authors present the case of a dumbbell-shaped schwannoma of the upper cervical spine involving the ventral rami of C-2 sensory root and rising through the foramen magnum up to the pontobulbar junction. The 27-year-old male patient complaining of hoarseness, imbalance and experiencing cervical pain and cervical muscle contractions for 2 months was admitted to the hospital. The cervical T1 and T2- weighted magnetic resonance (MR) images revealed the presence of a slightly hyperintense left C1-2 intra-extradural lesion which had eroded the clivus and odontoid process and enlarged the intervertebral foramen and was rising up to ponto-bulbar junction. A posterior approach was used to perform a suboccipital craniectomy and C1- 2 laminectomy, including opening of the dura mater and gross-total removal of the lesion. The cerebrospinal MR image of the patient obtained at the early post-operative period revealed total removal of the lesion. The patient had hypoglossal nerve palsy and mild hemiparesis on the left side which had regressed almost totally at the 3-month follow-up. The far-lateral approach with the patient in the sitting position is very important and facilitates the total removal of the schwannoma. Simple suboccipital craniectomy provided enough exposure for total removal in this case.

A case of unilateral hypoglossus nerve palsy associated with chordoma in the region of clivus

We had a rare case of 50-year-old woman with a unilateral hypoglossus nerve palsy as a sign of clival chordoma. A computed tomography (CT) scan of the skull base showed bone destruction at the anterior part of the foramen magnum and CT scan of the neck reveals asymmetrical area at the base of the tongue. Magnetic resonance imaging showed a mass at the skull base in the region of the clivus with bone destruction in the middle and right side of the clivus. The tumor was biopsied through transnasal biopsy from the region of the clivus using a navigation system and microscopical surgical technique. Postoperatively, the patient received radiotherapy. Surgery is the most effective treatment of chordomas. An endoscopic approach provides easy, rapid and direct access to the clivus. A postoperative radiation therapy is recommended. A carbon ion radiotherapy is an effective treatment for chordomas of the skull base with minimal side effects. Close interdisciplinary collaboration between ORL, neuroradiology, pathology and oncology is desirable for effective therapy.

Hypoglossal schwannoma-successful reinnervation and functional recovery of the tongue following tumour removal and nerve grafting

OBJECTIVE

Hypoglossal nerve schwannomas are rare tumours that usually cause ipsilateral hypoglossal palsy. This report describes such lesions in two patients and suggests nerve grafting as part of the treatment regimen.

METHOD

Two patients with intra- and extra-dural hypoglossal schwannomas respectively were treated by direct surgery via a postero-lateral approach to the posterior fossa, hypoglossal canal and carotid sheath. Following tumour removal, sural nerve grafting was used to reconstruct the nerves. Unexpectedly, muscle bulk and motor function returned within 6 months in both patients.

CONCLUSION

Nerve grafting was highly successful in achieving functional recovery following surgery for hypoglossal nerve schwannomas.

Suture of transected nerve suppresses expression of BH3-only protein Noxa in nerve-transected motor neurons of C57BL/6J mouse

Disrupted peripheral nerves are typically sutured as spontaneous recovery does not always occur. However, the molecular mechanisms involved in nerve regeneration following end-to-end nerve suture are obscure. Here, we investigated effects of end-to-end nerve suture after peripheral nerve transection on motor neurons, using the C57BL/6J mouse hypoglossal nerve injury model. In this animal model, 60-80% of injured motor neurons gradually progress to neuronal death, while the remaining injured neurons survive and regenerate. Mice were divided into the Cut and Suture groups. In the Cut group, the right hypoglossal nerve was transected. In the Suture group, the right hypoglossal nerve was transected and then was repaired using end-to-end nerve suture. We assessed differences between the Cut and Suture groups by analyzing the neuronal survival rate by thionine staining and the nerve terminal regeneration rate by vesicular acetylcholine transporter (VAChT) immunohistochemistry, which is a marker for cholinergic presynaptic terminal. We found that 82.9% of motor neurons survived in the Suture group, whereas only 39.2% of motor neurons did in the Cut group 56 days after surgery. At that time point, 86% of presynaptic terminals compared to controls were regenerated in the Suture group, and 21% were regenerated in the Cut group. These results demonstrate that peripheral nerve suture prevented death of nerve-transected motor neurons and promoted nerve regeneration. We also examined expression profiles of major survival and death signal-associated genes in hypoglossal nuclei using in situ hybridization and real-time polymerase chain reaction (PCR). Although most of the survival- and death-associated genes were regulated in a similar manner in both groups, expression of BH3-only protein Noxa mRNA was significantly lower in the Suture than in the Cut group. A significant suppression of Noxa expression by the Suture may be a major reason why nerve suture induces survival and regeneration of nerve-injured motor neurons.

"Triple cross" of the hypoglossal nerve and its microsurgical impact to entrapment disorders

OBJECTIVE

Cadaveric dissections were performed to review the intracranial and extracranial course of the hypoglossal nerve. The neurological significance of a newly defined "triple cross" of the hypoglossal nerve is discussed.

MATERIALS AND METHODS

10 cadaveric heads (left and right; 20 sides) were dissected using microsurgical techniques.

RESULTS

In the cisternal segment of hypoglossal nerve, the diameter of the rostral trunk amounted to 155-680 microm (mean 435 microm), and the caudal trunk to 210-820 microm (mean 482 microm). The roots formed three trunks in 20% of the hypoglossal nerves and two trunks in the rest. As a first cross, the anterior medullary segment of the vertebral artery crossed the hypoglossal nerve roots in 14 of 20 sides (70%). As a rare variation, the vertebral artery extended medial to the nerve (25%) or between its roots (5%). The second cross was found between the descendens hypoglossus and the occipital artery (75%), sternocleidomastoid artery and vein complex (15%) and external carotid artery (10%). The third cross was shown in the submandibular triangle between the lingual hypoglossus and its drainage vein; vena committans nervus hypoglossus.

CONCLUSION

Throughout its way, the hypoglossal nerve passes over vascular structures in three crossing points which may serve as a probable cause of hypoglossal nerve entrapment disorders.

The midline suboccipital subtonsillar approach to the hypoglossal canal: surgical anatomy and clinical application

Primary lesions of the hypoglossal canal, such as hypoglossal schwannomas, are rare. No consensus exists with regard to the surgical approach of choice for treatment of these lesions. Usually, lateral transcondylar approaches have been used. The authors describe the surgical anatomy of the midline subtonsillar approach to the hypoglossal canal. This approach includes a midline suboccipital craniotomy, dorsal opening of the foramen magnum and elevation of ipsilateral cerebellar tonsil to expose the hypoglossal nerve and its canal. The midline subtonsillar approach permits a straight primary intradural view to the hypoglossal canal. There is no necessity of condylar resections. The surgical anatomy of the subtonsillar approach is described and illustrated by an example of a case.

[Neurilemmoma of the head and neck--report of 3 cases]

BACKGROUND

Neurilemmoma are benign tumors of the nerve-sheath, also known as schwannoma. Beside intracranial manifestation, neurilemmoma are found at other peripheral nerves of the head and neck.

CASE REPORT

We present three cases of patients with seldom manifestation of neurilemmoma of the supraglottis, the retropharyngeal space and a neurilemmoma of the hypoglossal nerve. The histological examination showed two types of Antoni-A-neurilemmoma, whereas one tumor was found with mixed type A and B-neurilemmoma.

CONCLUSION

Although extracranial neurilemmoma of retropharygeal space, neck or supraglottic larynx are rare tumors, neurilemmoma should be involved in differential diagnosis of tumors in these areas. The therapy of choice consists of complete surgical removal and histological examination.

Das „ancient schwannoma“

"Ancient schwannomas" of the mouth floor are rare, benign neoplasms derived from the nerve sheath of peripheral nerves. They show many degenerative changes such as necrosis and vascular thrombosis. Ancient schwannomas show histopathological features, such as degenerative changes and atypical nuclei, and may easily be confused with malignant neoplasms. B-scan sonography for the mouth floor and MRT imaging may be helpful in differential diagnosis. Here, we report on a patient with ancient schwannoma of the floor of the mouth.

Usefulness of transcervical approach for surgical treatment of hypoglossal schwannoma with paraspinal extension: case report

BACKGROUND

Usefulness of transcervical approach to hypoglossal schwannoma with paraspinal extension is described herein.

CASE DESCRIPTION

A 54-year-old woman presented with gradually worsening left hypoglossal nerve palsy. The findings were of a tumor lying in the left hypoglossal canal and paraspinal region and were consistent with hypoglossal schwannoma. Subtotal intracapsular removal of the tumor was performed via transcervical approach. The symptoms improved, and no additional symptoms were noted.

CONCLUSION

The transcervical approach and intracapsular removal of the tumor under electrophysiological monitoring provided for successful minimally invasive surgery in this case of hypoglossal schwannoma.

Extracranial internal carotid artery aneurysm presenting as symptomatic hypoglossal and glossopharyngeal nerve paralysis

Aneurysms of the extracranial portion of the internal carotid artery are rare, particularly in young patients. They usually develop following trauma, or secondary to infection involving the parapharyngeal space that extends to the vessel wall. This is a case of an internal carotid artery aneurysm presenting acutely following chiropractic neck manipulation with hypoglossal and glossopharyngeal nerve palsy. The imaging findings and subsequent operative management are described.

Endoscope-assisted microsurgical resection of an intraneural ganglion cyst of the hypoglossal nerve

✓ An unusual case of an intraneural ganglion cyst of the hypoglossal nerve is presented. Only one case of this rare clinical entity has been reported previously. A 51-year-old woman presented with a 6-month history of left-sided hypoglossal nerve palsy. Magnetic resonance imaging revealed a cystic lesion related to the hypoglossal canal. There was no enhancement of the lesion after administration of Gd. A high-resolution computerized tomography scan of the skull base demonstrated an enlargement of the hypoglossal canal.

To access the lesion, a far-lateral endoscope-assisted microsurgical approach was used. An intraneural ganglion lesion invading the hypoglossal nerve was found and resected. A histopathological examination confirmed that the lesion was an intraneural ganglion cyst. The occurrence of an intraneural ganglion cyst at the hypoglossal nerve is very rare. This case exemplifies an atypical location of a synovial cyst with cranial nerve involvement.

Current management of head and neck schwannomas

PURPOSE OF REVIEW

The purpose of this review is to discuss the contemporary management of head and neck schwannomas by reviewing the literature and presenting the authors' experience.

RECENT FINDINGS

Molecular studies are attempting to link genetic factors to the development of nerve sheath tumors. Many studies emphasize the importance of preserving the nerve of origin, but structural preservation may not necessarily lead to the preservation of its functional integrity. The importance of neural reconstruction and postoperative rehabilitation is also emphasized.

SUMMARY

Head and neck schwannomas are uncommon tumors that may affect any peripheral, cranial, or autonomic nerve. This explains their variation in terms of location, clinical presentation, and outcome after surgical resection. History, physical examination, fine needle aspiration, and magnetic resonance imaging are used as diagnostic modalities. Cure entails a complete resection, all attempts being made to preserve the nerve of origin. Otherwise, immediate reconstruction and postoperative rehabilitation should be undertaken in the context of a multidisciplinary management team.

Navigated dorsolateral suboccipital transcondylar (NADOSTA) approach for treatment of hypoglossal schwannoma

Hypoglossal schwannoma is a rare skull base neoplasm, which lies in the midst of extremely complex anatomical structures. We report a 39-year-old man who presented with a history of right glossal hemiatrophy, dysesthesia and weakness of the left extremities. These symptoms were caused by a unilateral hypoglossal schwannoma located at the cranial base. This lesion was exposed through a dorsolateral suboccipital transcondylar approach, which was navigated with the frameless stereotaxy (NADOSTA). We also describe the epidemiology, symptomatology and the diagnosis of hypoglossal schwannoma as well as literature review of the operative approach. By introducing this minimally invasive dorsal surgical approach with neuronavigation in treating hypoglossal schwannoma, we believe that safe exposure and complete tumor resection can be achieved with minimal rate of morbidity.

[Hypoglossal neurilemmoma: current experience in diagnosis and treatment]

OBJECTIVE

To improve the diagnosis and treatment of hypoglossal neurilemmoma (HGN).

METHODS

The data of 10 patients with HGN were retrospectively reviewed, 5 of 10 patients (early group) had been reported previously. A comparison of treatment strategy between early and latter group was made.

RESULTS

Typical hemiatrophy of the tongue presented in all 10 patients, hypoglossal canal could be showed in the bone window of CT, which, however, might not confirm the existence of tumor if it is very small. MRI was the optical choice for diagnosis. Among the early 5 cases with HGN which were all of dumbbell type, the intracranial part and the extracranial part of the tumor in 2 cases were removed by stages, 3 cases were operated via the far-lateral approach, of which 1 was via trans-condylar approach and 2 were via trans-supracondylar approach; the 5 tumors were removed subtotally except 1 totally; CSF leakage and intra-cranial infection after operation occurred in 1 case; the rating of Karnofsky Prognosis Scale was good in 4 cases and dead in 1 case. However, among the latter 5 cases, 4 cases including 2 of dumbbell type, 1 of intra-cranial type and 1 of intracanal type were operated via the modified far-lateral approach, of which 1 was via trans-condylar approach and 3 were via trans-supracondylar approach; and the tumor of extracranial type in the last case was resected twice via transcervical approach, being removed subtotally in the first operation followed by total removal with the aid of neuronavigation and neuroendoscopy in the second operation when it failed to react to the treatment of gamma knife; the 5 tumors were removed totally except 1 subtotally.; all postoperative courses were uneventful.; follow up was performed successfully in 4 cases, the rating of Karnofsky Prognosis Scale was excellent in 3 cases and fair in 1 case. The outcomes of the latter 5 cases resected via modified approach were better than those of the early 5 cases.

CONCLUSION

HGN is extremely rare and it is difficult to treat it. To achieve a good operative outcome, it is very important to design the approach individually based on its location and size and operate mini-invasively and resect tumor totally as possible as can in the primary stage.

[Postauricular tran-supracondylar approach removed jugular foramen and hypoglossal canal tumors]

OBJECTIVE

Discuss the surgical treatment of jugular foramen and hypoglossal canal tumor, and choice of the best surgical approach.

METHODS

32 patients with jugular foramen and hypoglossal canal tumor were operated through the postauricular tran-supracondylar approach, 13 neurinoma, 7 glomus jugular tumors, 4 meningioma, 3 chordoma. 23 were total removed, with a subtotal of 9.

RESULTS

21 patients were followed up, mean 2.5 years. 18 patients work normally, 7 of them were hoarseness, 2 of other 3 patients lived by themselves, 1 of existed obstruct of limbs.

CONCLUSIONS

Postauricular tran-supracondylar approach exposes satisfactory for the dumbbell-shape tumors of intra-or extra cranial. It has high rate of total removal and low rate of complications. It is the best approach of treatment in jugular foramen and hypoglossal canal tumors. The outcome is good.

Bilateral hypoglossal schwannoma: a radiologic diagnosis

A 53-year-old woman presented with a complaint of a sore throat. Examination showed a left-sided atrophy of the tongue. Upon protrusion, the tongue deviated to the left, suggestive of a unilateral hypoglossal nerve palsy. Computed tomography revealed enlarged hypoglossal canals. Magnetic resonance imaging (MRI) demonstrated bilateral hypoglossal canal masses, with enhancement following gadolinium administration. Magnetic resonance angiography and MRI with fat suppression revealed nonvascular masses in both hypoglossal canals. Radiological diagnosis of bilateral hypoglossal nerve schwannoma was made and the patient was scheduled for MRI monitoring with six-month intervals. The size of the masses and the clinical manifestations remained unchanged during a two-year follow-up period.

Fibrous dysplasia of the clivus

OBJECTIVE

Fibrous dysplasia is a developmental skeletal disorder that may lead to distortion, expansion, and weakening of the bone. Craniofacial involvement by this entity is well recognized and is known to cause neurovascular impingement and cosmetic deformity; fibrous dysplasia of the clivus, however, is unrecognized and seldom reported. Differentiating this entity from more aggressive disease processes affecting the clivus is central for the proper management of lesions in this area. We have studied fibrous dysplasia of the clivus with the goal of depicting its manifestations, outlining its management, and heightening awareness of this disease entity.

METHODS

We retrospectively reviewed our database and identified patients with the diagnosis of fibrous dysplasia of the clivus. The demographic data, the clinical and radiological findings, and the management of these patients were reviewed.

RESULTS

Eight patients who had experienced fibrous dysplasia of the clivus were identified. They either were asymptomatic (four patients) or presented with headache (four patients). Of the patients who presented with headache, one also had XIIth cranial nerve paralysis and another had dysphagia. The radiological findings for this entity were consistent, with typical findings of hypointensity on T1- and T2-weighted magnetic resonance imaging studies and ground-glass appearance on computed tomographic scans. Four of the patients in our series had pathological confirmation. Treatment was determined by the patient's symptoms.

CONCLUSION

Fibrous dysplasia should be considered in the differential diagnosis of lesions affecting the clivus. Its clinical and radiological presentations permit the establishment of the diagnosis. Its management is usually conservative, unless the patient presents with nerve compression or extensive symptomatic involvement of the condyle.

Dumbbell-shaped hypoglossal schwannoma. A case report

Dumbbell-shaped neuromas of the 12th cranial nerve extending intra- and extracranially are extremely rare. The present paper reports on a 32-year-old patient who presented with hypoglossal nerve palsy and a two-year history of headache. MRI showed inhomogeneous contrast agent enhancement in a tumor that was partly cystic, partly solid, in the cerebellopontine cistern. The tumor, with its main lesion mass located in the parapharyngeal space, extended along the canal of the hypoglossal nerve. The tumor was excised by two-stage suboccipital osteoclastic craniotomy and later through a cervical approach. Pathohistology showed a grade I schwannoma and the patient was discharged symptom-free without any further therapy.

Rare localization of paraganglioma in head and neck

In this paper, we describe the clinical course of a 61-year-old female patient with paraganglioma in the head and neck region. Computed tomographic scan (CT), magnetic resonance imaging (MRI), ultrasound scan (US) and arteriogram findings initially led us to suspect that this tumor originated in the vagal nerve. In particular, a color Doppler US enabled an easy diagnosis of hypervascular tumor. We removed this surgically, but the tumor was easy to peel from the vagal nerve and carotid bifurcation. The distal side of the tumor was under the digastric muscle and running into the hypoglossal nerve. The intraoperative findings were highly suggestive of localization at the hypoglossal nerve, although Xth and XIIth cranial nerve palsies have remained.

Stereotactic radiosurgery: the preferred management for patients with nonvestibular schwannomas?

PURPOSE

To review patient outcomes after radiosurgery of nonvestibular schwannomas.

MATERIALS AND METHODS

From April 1992 to February 2000, 23 patients had radiosurgery at our center for nonvestibular schwannomas. Affected cranial nerves included the trochlear (n = 1), trigeminal (n = 10), jugular foramen region (n = 10), and hypoglossal (n = 2). Nine patients had undergone one or more prior tumor resections. One patient had a malignant schwannoma; 2 patients had neurofibromatosis. The median prescription isodose volume was 8.9 cc (range, 0.2 to 17.6 cc). The median tumor margin dose was 18 Gy (range, 12 to 20 Gy); the median maximum dose was 36 Gy (range, 24 to 40 Gy). The median follow-up after radiosurgery was 43 months (range, 12 to 111 months).

RESULTS

Twenty-two of 23 tumors (96%) were either smaller (n = 12) or unchanged in size (n = 10) after radiosurgery. One patient with a malignant schwannoma had tumor progression outside the irradiated volume despite having both radiosurgery and fractionated radiation therapy (50.4 Gy); he died 4 years later. Morbidity related to radiosurgery occurred in 4 patients (17%). Three of 10 patients with trigeminal schwannomas suffered new or worsened trigeminal dysfunction after radiosurgery. One patient with a hypoglossal schwannoma had eustachian tube dysfunction after radiosurgery. No patient with a lower cranial nerve schwannoma developed any hearing loss, facial weakness, or swallowing difficulty after radiosurgery.

CONCLUSIONS

Although the reported number of patients having radiosurgery for nonvestibular schwannomas is limited, the high tumor control rates demonstrated after vestibular schwannoma radiosurgery should apply to these rare tumors. Compared to historical controls treated with surgical resection, radiosurgery appears to have less treatment-associated morbidity for nonvestibular schwannomas, especially for schwannomas involving the lower cranial nerves.

Hypoglossal schwannoma in the submandibular space

Most schwannomas of the hypoglossal nerve originate from the intracranial portion, but they may extend extracranially. Solitary and extracranial schwannomas are extremely rare. We report a case of submandibular hypoglossal schwannoma along with its clinical course and management.

[How I treat ... facial paralysis by hypoglosso-facial anastomosis]

Thirteen patients underwent a hypoglosso- or a spino-facial nerve anastomosis between 1990 and 1996. Facial palsy was the result of surgery in 12 cases and of radiosurgery in 1 case. The mean interval between facial palsy and anastomosis was 12 months. Facial nerve function is determined on the basis of clinical examination according to the classification of House-Brackmann and our own evaluation. According to House, 10 patients are classified grade III and 3 grade IV. Our evaluation defines in 10 grade III, 7 good results and 3 fair results. As far as the good results are concerned, the mean interval between palsy and anastomosis is short (< 3 months). The permanent eating and swallowing dysfunctions are consecutive to multiple cranial nerve deficits. The post-paralysis hemifacial spasm is facilitated by prolongated electric stimulations.

[Diagnosis and treatment of hypoglossal neurinoma]

OBJECTIVE

To investigate the symptoms, diagnosis, operative approaches and prognosis of hypoglossal neurinoma.

METHODS

The clinical symptoms, radiological features, prevalence, operative approaches and prognosis of 9 cases of hypoglossal neurinoma were analyzed.

RESULTS

Cases of neurinoma of the hypoglossal nerve accounted for 1.9% of the cases of skull base neoplasm in the same period. Most of the tumor was in the shape of dumbbell, involving both intracranial and extracranial segments of the nerve. In a few cases, the tumor mainly involved the intracranial segment of hypoglossal nerve. All the cases were operated on, of which 7 through extreme-far-lateral approach, 1 through extreme-far-lateral approach combined with cervical approach, and one through the midline approach. Total resection was achieved in all cases. Follow up was performed in 7 cases, among which 5 cases returned to their work, 1 resumed the ability of self-care, and one still required care of others.

CONCLUSION

As the hypoglossal canal is next to the jugular foramen and foramen magnum, preoperative diagnosis of the hypoglossal neurinoma is difficult. The most common initial symptom is atrophy of tongue muscle. Radical resection is the best choice of treatment. The extrem-far-lateral approach is the best approach for operation. The prognosis is inspiring after operation.

[Neurinoma of the cervical hypoglossal nerve. A clinical case and review of the literature]

Neurilemmomas are relatively rare tumors derived from Schwann cells that may occur at any part of the body. Many are encapsulated and they are more frequently encountered in adults. A neurilemmoma of the hypoglossal cervical nerve, an unusual site, is reported. Submaxillary angioma was initially suspected.

Hypoglossal neurinoma--two case reports

Two patients presented with hypoglossal neurinoma extending both intra- and extracranially. A 63-year-old male presented with right trigeminal neuralgia and hypoglossal nerve paresis. The intracranial part of the tumor was removed totally via a suboccipital craniectomy. Over-coagulation of the venous collaterals, particularly the emissary veins, resulted in dural venous sinus thrombosis and cerebellar infarction. Unfortunately this patient died. A 48-year-old male presented with pareses of the VII, IX, X, XI, and XII cranial nerves and cerebellar sign. The tumor extended both extra- and intracranially, and was completely removed by opening the hypoglossal canal and the jugular foramen without over-coagulation of the venous collaterals. Preservation of the venous collaterals is very important for the prevention of postoperative venous complications.