Intradural microsurgery and extradural gamma knife surgery for hypoglossal schwannoma: case report and review of the literature

Stereotactic radiosurgery for the treatment of hypoglossal schwannoma: a multi-institutional retrospective study

BACKGROUND

Surgical removal has been performed as the first line treatment for symptomatic or enlarging hypoglossal schwannomas (HS). Stereotactic radiosurgery (SRS) offers a minimally invasive approach that may afford long-term tumor control for patients with HS particularly those who refuse or are unfit for surgery. This study evaluates outcomes after SRS performed for both newly diagnosed and residual tumors after incomplete resection.

METHODS

This retrospective, multi-institutional study involved patients treated with adjuvant or primary SRS for HS. The study end-points included local tumor response, clinical outcomes, and procedure-related complications. All the patients had Gamma Knife SRS.

RESULTS

The cohort included 12 patients (five females), median age at SRS 49.5 years (range, 37-76)]. The median tumor target volume was 5.9 cm³ (range, 0.7-27.23). At median imaging follow-up of 37 months (range, 6-153), tumor control was achieved in 11 patients. Tumor enlargement that was managed with surgical resection was noted at the 6-month follow-up in one patient. At median clinical follow-up of 30.5 months (range, 6-157), stability, or improvement of all pre-SRS signs and symptoms was noted in nine patients. Two patients experienced worsening of at least one pre-existing symptoms or sign. New-onset trapezius weakness was noted in one patient and tongue atrophy in two patients.

CONCLUSION

Single-fraction SRS appears to be a safe and effective upfront and adjuvant treatment option for HS. SRS may be recommended as an alternative to surgery for patients presenting with HS or as an adjuvant treatment following subtotal resection and at HS recurrence.

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.

Dumbbell-shaped solid-cystic hypoglossal schwannoma: An unusual case report

Hypoglossal Schwannomas are extremely rare benign slow-growing neoplasms, which originate from the 12th cranial nerve. To date, and to the best of our knowledge, only 40 cases of dumbbell-shaped Hypoglossal Swchannomas have been published in the world literature. We report our experience with a 66 years old male patient, who was diagnosed with a solido-cystic lesion at the right cerebello-pontine angle arising from XIIth cranial nerve. He was treated with surgery via midline suboccipital approach which led to sub-total removal of the tumor and improvement of the symptoms within 3 months. This case highlights the importance of an accurate suspicion diagnosis of hypoglossal schwannoma as well as the treatment options including surgery and radiosurgery.

Hypoglossal schwannomas: A systematic review of the literature

BACKGROUND

Schwannomas of the hypoglossal nerve are rare and account for a very small percentage of non-vestibular schwannomas.

OBJECTIVES

In this systematic review of the literature, we examined the epidemiology, symptomatology, management, and outcomes of patients with hypoglossal schwannomas.

METHODS

The electronic database Pubmed was searched for all reports of hypoglossal schwannomas with descriptions of symptoms, management, and outcome characteristics. Data was extracted from each study and compiled in a spreadsheet. Continuous variables were reported as means and medians. Categorical variables were reported as proportions. Additional analysis was not done due to inconsistent reporting of outcomes and small sample sizes.

RESULTS

A total of 59 studies (94 total individual cases) were included. 64% of patients were female with mean age of 44.6 years. The majority were intracranial/extracranial (50%). The most common symptoms were tongue deviation or speech disturbance (38%) and headaches (33%). Hypoglossal nerve dysfunction was present in 80% of patients. Surgical excision was performed in 93%, with a 15% complication rate. Evidence of residual mass after surgery was noted in 29%. Permanent hypoglossal nerve deficits occurred in 67%. Recurrence of tumor burden was reported in 6 studies, with median time to recurrence of 16.5 months.

CONCLUSION

Current evidence suggests overall favorable outcomes with surgical resection of hypoglossal schwannomas, with a large percentage of patients experiencing mild and usually well-tolerated neurologic deficit. Limitations of this study include the use of retrospective data taken from case reports/series with highly selected patients, selective reporting, and absence of control groups.

Partial skull base tumour resection in combination with radiosurgery: an escape procedure or a reasonable solution of treatment?

Despite advancement in microsurgical techniques for skull base tumour surgery, approaches of this kind still represent a significant challenge for neurosurgeons due to the size of the tumour and its interference and proximity to important neural and vascular structures. After incomplete resection, gamma knife radiosurgery is becoming an alternative or adjunctive treatment option. In this article, some examples of our experience in combined treatment of the skull base tumours with surgical procedure and gamma knife therapy for the remaining tumour tissue are presented.

Using a modified far-lateral approach to remove hypoglossal neurilemmomas: notes on technique

OBJECT

In this paper the authors describe a modified far-lateral transcondylar approach to remove hypoglossal neurilemmomas (HGNs).

METHODS

Between September 2008 and June 2011, 11 consecutive patients with HGNs underwent tumor removal via a modified far-lateral transcondylar approach. The average age at presentation, tumor characteristics, cranial nerve (CN) deficits, and outcomes were assessed. The modified far-lateral transcondylar approach comprises several important steps. The first step is to remove the limited posterior aspect of the condylar facet to open the hypoglossal canal. The second step is to expose the posterior arch and the transverse process of C-1. A fat layer covers the venous plexus of the vertebral artery, and careful dissection along this surface of the fat layer is important to protect the vertebral artery from damage. The neck muscles are dissected caudally to expose the extracranial component of the tumor, which is located in front of the transverse process of C-1.

RESULTS

Eleven cases of HGNs were treated during the study period. The mean patient age was 47.4 ± 8.9 years (range 31-59 years); there were 3 men and 8 women. The mean follow-up period was 14.1 ± 9 months. All patients presented with hypoglossal nerve deficits; other commonly observed deficits included glossopharyngeal and vestibular/cochlear nerve deficits. Gross-total resection of the tumor was achieved in 10 patients. A subtotal resection of the tumor was achieved in the remaining patient. Two patients had transient postoperative facial nerve palsies, 1 patient developed a new CN XI palsy postoperatively, and 5 patients experienced transient hoarseness and difficulty swallowing. Two patients required a tracheotomy because they demonstrated dysfunction of the caudal CNs and subsequently developed postoperative pneumonia. Postoperatively, 5 patients required the temporary placement of a nasogastric feeding tube. There were no surgery-related deaths in this series.

CONCLUSIONS

The modified far-lateral transcondylar approach is an effective treatment for HGNs, yielding a high total tumor removal rate with an acceptable rate of morbidity.

Microsurgical management of hypoglossal schwannomas over 3 decades: a modified grading scale to guide surgical approach

BACKGROUND

Schwannomas originating from the hypoglossal nerve are extremely rare. Microsurgical resection with the goal for cure has traditionally been associated with a high risk of postoperative deficits.

OBJECTIVE

To summarize our clinical experience using tailored cranial base approaches for these formidable lesions.

METHODS

The clinical records of 13 patients were retrospectively reviewed. In addition, all reported patients in the literature were reviewed. The extreme lateral infrajugular transcondylar-transtubercular exposure approach was used in all of our patients. Based on our experience and literature analysis, we propose the following modified grading scale to facilitate surgical planning: type A, intradural tumors; type B, dumbbell-shaped tumors; type C, extracranial tumors; and type D, peripheral tumors.

RESULTS

All 13 patients underwent total, near-total, or subtotal tumor resection. Eight patients were men, 5 were women (mean age, 41.7 years). Sural nerve graft reconstruction for the hypoglossal nerve was performed in 4 patients. Three of the 4 patients in whom nerve reconstruction was performed regained satisfactory movement of their tongue. In the review of the literature, the mean patient age was 45.8 years. Patients presented with tongue atrophy (91.6%), headache (60.9%), and dysphagia (31.8%). The tumors were categorized as type A in 31.7% of these patients, type B in 38.6%, type C in 6.2%, and type D in 23.4%.

CONCLUSION

The extreme lateral infrajugular transcondylar-transtubercular exposure approach, which is a modification of the extreme lateral suboccipital approach, provides sufficient exposure for most intracranial dumbbell-shaped hypoglossal schwannomas. Hypoglossal nerve reconstruction using a sural nerve graft improves tongue atrophy and movement for patients with resected nerves.

Endoscopic endonasal clipping of a ruptured vertebral-posterior inferior cerebellar artery aneurysm: technical case report

BACKGROUND AND IMPORTANCE

Aneurysms arising from the vertebral and posterior inferior cerebellar artery complex account for only 0.5 to 3% of all aneurysms. Surgery for these aneurysms is technically challenging because of the deep location and intimate relation with the medulla and lower cranial nerves. The authors report the case of a patient with a right vertebral-posterior inferior cerebellar artery complex (VA-PICA) aneurysm that was successfully clipped via an extended endoscopic endonasal transclival approach.

CLINICAL PRESENTATION

A 74-year-old woman with the sudden onset of severe headache, nausea, and vomiting was admitted to our hospital. A computed tomography (CT) of the brain revealed diffuse subarachnoid hemorrhage associated with intraventricular hemorrhage and incipient hydrocephalus. Cerebral angiography revealed a 1.2-mm aneurysm arising at the origin of the right PICA. The aneurysm was considered unsuitable for selective coil embolization, so neck clipping was performed. With the use of an extended endoscopic endonasal transclival approach, the aneurysm was accurately reached endoscopically and successfully clipped from the parent artery. The patient was discharged neurologically intact.

CONCLUSION

To the best of the authors' knowledge, this is the first report of a successfully treated VA-PICA ruptured aneurysm using a pure endoscopic endonasal transclival approach. Endoscopic surgery may be added to the armamentarium of procedures for the treatment of posterior circulation aneurysms.

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.