Surgical outcome in smaller symptomatic vestibular schwannomas. Is there a role for surgery?

BACKGROUND: Currently, there is no consensus in the initial management of small vestibular schwannomas (VSs). They are routinely watched and/or referred for radiosurgical treatment, although surgical removal is also an option. We hereby evaluate clinical outcomes of patients who have undergone surgical removal of smaller symptomatic VSs. METHODS: Patients with vestibular schwannomas (grade T1-T3b according to Hannover classification) were reviewed. Patients with symptomatic tumors who underwent surgery were evaluated. Their preoperative hearing status was based on the guideline of the committee on hearing and equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) foundation. Their postoperative facial nerve function, hearing status, vestibular symptoms, and degree of tumor resection were assessed. RESULTS: Thirty patients were selected for surgery via a retrosigmoid approach based on their age, symptoms, and their own decision-making after discussion of management options. Most patients presented with hearing loss. Seventeen patients had useful hearing preoperatively. Among them, 10 patients (59%) preserved useful hearing (class A or B) postoperatively. MRI at 1-year follow-up confirmed complete resection in 26/29 patients. Also, 29 patients (97%) had HB grade I-II, and 1 patient had HB III at 1-year follow-up. Except for 1 patient with CSF leak, 1 patient with delayed facial nerve palsy, and 2 patients with asymptomatic sigmoid sinus occlusion, there were no other new morbidities. CONCLUSION: Although both observation and radiosurgery are valid options in the management of smaller size vestibular schwannomas, surgical treatment seems to offer a high rate of facial nerve preservation, a reasonable rate of hearing sparing, and a high total resection rate. Clinicians should consider surgical treatment as a valid option in the initial management of symptomatic small vestibular schwannomas in younger patients.

Intradural Extramedullary Cavernous Malformation of the Spinal Cord with Hemorrhagic Transformation and Rapid Expansion.

Intradural extramedullary cavernous malformations in the spinal cord are rarely occurring vascular lesions. Mostly they are clinically silent unless the hemorrhagic transformation causes subarachnoid hemorrhage or neurologic deficits. We report the case of a 51-year-old man who developed a headache and weakness of the lower limb. Spinal cord magnetic resonance imaging revealed that the cause of his symptoms was a spinal intradural and extramedullary cavernous malformation with hemorrhagic transformation causing subarachnoid hemorrhage and compression of the thoracic spinal cord. Surgical decompression of the spinal cord followed by the resection of the lesion resulted in significant neurological improvement. Early diagnosis and early surgical extirpation of the lesion should be done to prevent recurrent hemorrhagic transformation and development of neurological symptoms.

Retrosigmoid transhorizontal fissure approach to lateral pontine cavernous malformation: comparison to transpetrosal presigmoid retrolabyrinthine approach.

OBJECTIVE: The retrosigmoid (RS) approach is a classic route used to access deep-seated brainstem cavernous malformation (CM). The angle of access is limited, so alternatives such as the transpetrosal presigmoid retrolabyrinthine (TPPR) approach have been used to overcome this limitation. Here, the authors evaluated a modification to the RS approach, horizontal fissure dissection by using the RS transhorizontal (RSTH) approach. METHODS: Relevant clinical parameters were evaluated in 9 patients who underwent resection of lateral pontine CM. Cadaveric dissection was performed to compare the TPPR approach and the RSTH approach. RESULTS: Five patients underwent the TPPR approach, and 4 underwent the RSTH approach. Dissection of the horizontal fissure allowed for access to the infratrigeminal safe entry zone, with a direct trajectory to the middle cerebellar peduncle similar to that used in TPPR exposure. Operative time was longer in the TPPR group. All patients had a modified Rankin Scale score ≤ 2 at the last follow-up. Cadaveric dissection confirmed increased anteroposterior working angle and middle cerebellar peduncle exposure with the addition of horizontal fissure dissection. CONCLUSIONS: The RSTH approach leads to a direct lateral path to lateral pontine CM, with similar efficacy and shorter operative time compared with more extensive skull base exposure. The RSTH approach could be considered a valid alternative for resection of selected pontine CM.

Technical Note: Extreme Lateral Supracerebellar Approach for Resection of Superior Cerebellar Peduncle Arteriovenous Malformations.

BACKGROUND: The surgical approaches to the region of the cerebello-mesencephalic sulcus and superior cerebellar peduncle (SCP) remain a neurosurgical challenge. OBJECTIVE: To present the use of the extreme lateral supracerebellar infratentorial (SC-IT) approach to treat arteriovenous malformations (AVMs) of the SCP, which is a different entity compared to brainstem AVMs. METHODS: We treated 4 patients with SCP AVMs in the last 5 yr at our institution. The mean age was 49.7 yr. The average nidus size was 2.12 cm. Of those, 3 patients presented with hemorrhage and 1 with headache and tinnitus. Extreme lateral SC-IT approach was used in all cases. RESULTS: Complete resection was achieved in all cases as verified with postoperative angiogram. In 1 case, intraoperative rupture with intraventricular hemorrhage was encountered, and the patient required temporary external ventricular drainage. There was no permanent complication or neurological deficit. The modified Rankin Scale (at discharge or follow-up) was less than 2 in all cases. CONCLUSION: The AVMs located primarily in the SCP are distinct compared to brainstem AVMs, and their management should be different. Extreme lateral SC-IT approach should be considered as a viable alternative surgical approach for resection of these AVMs, and excellent surgical results can be achieved.

Surgical Trapping of a Large Complex Middle Cerebral Artery Aneurysm With Double-Barrel Bypass: 3-Dimensional Operative Video.

Large middle cerebral artery (MCA) bifurcation aneurysms are known vascular lesions that are usually symptomatic but often difficult to treat (whether with open or endovascular techniques), especially when the M2 branches originate from the aneurysm dome.1-7 The challenge lies in securing the aneurysm while fully maintaining the flow in the vessels arising from the dome. Standard microsurgical clipping or endovascular techniques are not feasible in perfectly treating these aneurysms. Revascularization of the MCA branches with bypass and trapping of the aneurysm is often necessary. Here, we present a case of a large complex partially thrombosed right MCA bifurcation aneurysm with both the superior and the inferior divisions arising from the dome. The patient initially presented with a right MCA stroke and left hemiparesis. Using radial artery as an interposition graft, 2 bypasses-internal maxillary artery to the inferior division and superficial temporal artery to the superior division-were performed. The aneurysm was trapped and decompressed by placing clips at the M1 terminus and the M2 origins. Intraoperative angiography and postoperative NOVA (VasSol Inc.) magnetic resonance angiography (MRA) confirmed patency and excellent flow in the bypass grafts. The patient's postoperative course was uncomplicated, and at 2-mo follow-up, had significant improvement of her hemiparesis. The patient provided informed consent for the procedure.

Surgical Resection of a Complex Spetzler-Martin Grade IV Medial Sylvian Arteriovenous Malformation: 3-Dimensional Operative Video.

Sylvian arteriovenous malformations (AVMs) are challenging lesions for surgical management. They are classified according to the Sugita classification based on the location of the nidus in the sylvian fissure: pure, lateral, medial, and deep. Resection of these lesions are fraught with risks, as it requires extensive arachnoid dissection in the sylvian fissure in close proximity to surrounding eloquent tissue, and the presence of en passage arteries can resemble feeding arteries. In this video illustration, the authors describe a complex, Spetzler-Martin Grade IV right sylvian AVM and its surgical resection. By Sugita classification, this was a medial sylvian AVM, with an associated flow related middle cerebral artery (MCA) bifurcation aneurysm. Informed consent was obtained from the patient prior to the procedures. The AVM was embolized preoperatively, and surgical resection was carried out via a pterional approach. The detail of the AVM resection is described in the video clip. Postoperative digital subtraction angiography showed complete excision of the lesion, and the patient was discharged to home on postoperative day 6 without any neurological deficit. In 1-yr follow-up angiogram, beside complete obliteration of the AVM, the flow-related MCA bifurcation aneurysm as well as the M1 and M2 vessels have decreased in size and are much less prominent in comparison to the pretreatment angiography.

Near Total Versus Gross Total Resection of Large Vestibular Schwannomas: Facial Nerve Outcome.

BACKGROUND: Large vestibular schwannomas (VSs) with brainstem compression are generally reserved for surgical resection. Surgical aggressiveness must be balanced with morbidity from cranial nerve injury. The purpose of the present investigation is to evaluate the clinical presentation, management modality, and patient outcomes following near total resection (NTR) vs gross total resection (GTR) of large VSs. OBJECTIVE: To assess facial nerve outcome differences between GTR and NTR patient cohorts. METHODS: Between January 2010 and March 2018, a retrospective chart review was completed to capture patients continuously who had VSs with Hannover grades T4a and T4b. NTR was decided upon intraoperatively. Primary data points were collected, including preoperative symptoms, tumor size, extent of resection, and postoperative neurological outcome. RESULTS: A total of 37 patients underwent surgery for treatment of large and giant (grade 4a and 4b) VSs. Facial nerve integrity was preserved in 36 patients (97%) at the completion of surgery. A total of 27 patients underwent complete resection, and 10 had near total (>95%) resection. Among patients with GTR, 78% (21/27) had House-Brackmann (HB) grade I-II facial nerve function at follow-up, whereas 100% (10/10) of the group with NTR had HB grade I-II facial nerve function. Risk of meningitis, cerebrospinal fluid leak, and sinus thromboses were not statistically different between the 2 groups. There was no stroke, brainstem injury, or death. The mean follow-up was 36 mo. CONCLUSION: NTR seems to offer a benefit in terms of facial nerve functional outcome compared to GTR in surgical management of large VSs without significant risk of recurrence.