Although the translabyrinthine approach was described by Panse in 1904 and first used to resect a cerebellopontine angle tumor by Quix in 1912, it was not until House published 47 resections with no mortalities in 1964 that the approach was truly popularized 1).
Since that time it has been well described in the literature as a useful approach for resection of vestibular schwannomas in cases where hearing preservation is not a concern. Additionally Morrison and King have described a modified use of this approach in combination with a transtentorial component for the resection of vestibular schwannomas and other lesions of the cerebellopontine angle and proximate anatomy 2).
Surgical series of translabyrinthine resections often include cerebellopontine angle meningiomas of the as well as the internal acoustic meatus, schwannomas of the facial and trigeminal nerves, and cholesteatomas, neurinomas, and chordomas – illustrating the multiple uses of this approach 3).
With the help of an endoscope, Sun et al exposed the internal auditory canal and cerebellopontine through a translabyrinthine approach and the inferior colliculus through a keyhole subtemporal approach. This double approach can be combined to expose the internal auditory canal and cerebellopontine angle and inferior colliculus satisfactorily in the same surgical setting. This combined approach can avoid retraction of the cerebellum and reduce serious adverse events and complications 4).
A study included 6 patients with internal auditory canal cavernous hemangioma. All patients presented with sensorineural hearing loss and tinnitus, and 2 also suffered from vertigo. Five patients reported a history of hemifacial spasm or facial palsy: 3 had progressive facial weakness, 1 had a hemispasm, and 1 had a history of recovery from sudden facial paresis. All patients underwent CT and MRI to rule out intracanalicular vestibular schwannomas and facial nerve neuromas. Five patients had their tumors surgically removed, while 1 patient, who did not have facial problems, was followed up with a wait-and-scan approach.
All patients had a presurgical diagnosis of cavernous hemangioma of the IAC, which was confirmed pathologically in the 5 patients who underwent surgical removal of the tumor. The translabyrinthine approach was used to remove the tumor in 4 patients, while the middle cranial fossa approach was used in the 1 patient who still had functional hearing. Tumors adhered to cranial nerves VII and/or VIII and were difficult to dissect from nerve sheaths during surgeries. Complete hearing loss occurred in all 5 patients. In 3 patients, the facial nerve could not be separated from the tumor, and primary end-to-end anastomosis was performed. Intact facial nerve preservation was achieved in 2 patients. Patients were followed up for at least 1 year after treatment, and MRI showed no evidence of tumor regrowth. All patients experienced some level of recovery in facial nerve function.
Cavernous hemangioma of the IAC can be diagnosed preoperatively through analysis of clinical features and neuroimaging. Early surgical intervention may preserve the functional integrity of the facial nerve and provide a better outcome after nerve reconstruction. However, preservation of functional hearing may not be achieved, even with the retrosigmoid or middle cranial fossa approaches. The translabyrinthine approach seems to be the most appropriate approach overall, as the facial nerve can be easily located and reconstructed 5).
A total of 417 patients with 420 tumors were analyzed, 209 female (50.1%) and 208 male (49.9%). Mean age at diagnosis was 49.8±13.2 years. The majority of the tumors were resected through a translabyrinthine approach (80.2%). Total tumor removal was achieved in 411 tumors (98.3%), and anatomic preservation of facial nerve in 404 (96.2%). Definitive facial nerve outcome was House-Brackmann grade I and II in 69.9%, and was significantly better in tumors under 20mm. Surgical complications included cerebrospinal fluid leakage in 3 patients (0.7%) and retroauricular subcutaneous collection in 16 (3.8%), 5 cases of meningitis (1.2%), 4 patients with intracraneal bleeding (0.9%), and death in 3 patients (0.7%).
Surgery is the treatment of choice for vestibular schwannoma in the majority of patients. In our experience, the complication rate is very low and tumor size is the main factor influencing postoperative facial nerve function 6).
52 patients (2004-2013), outcomes included extent of resection, postoperative hearing, and facial nerve function. Extent of resection defined as gross total, near total, or subtotal were 7 (39%), 3 (17%), and 8 (44%) in 18 patients after retrosigmoid approaches, respectively, and 10 (29.5%), 9 (26.5%), and 15 (44%) for 34 patients after translabyrinthine approaches, respectively.
Hearing was preserved in 1 (20%) of 5 gross total, 0 of 2 near-total, and 1 (33%) of 3 subtotal resections. Good long-term facial nerve function (House-Brackmann grades of I and II) was achieved in 16 of 17 gross total (94%), 11 of 12 near-total (92%), and 21 of 23 subtotal (91%) resections. Long-term tumor control was 100% for gross total, 92% for near-total, and 83% for subtotal resections. Postoperative radiation therapy was delivered to 9 subtotal resection patients and 1 near-total resection patient. Follow-up averaged 33 months.
The findings support facial nerve preservation surgery in becoming the new standard for acoustic neuroma treatment. Maximizing resection and close postoperative radiographic follow-up enable early identification of tumors that will progress to radiosurgical treatment. This sequential approach can lead to combined optimal facial nerve function and effective tumor control rates 7).
A retrospective study of 1865 patients who underwent VS excision through the enlarged translabyrinthine approach between 1987 and 2009. Mean age was 50.39 years. Mean tumor size was 1.8 cm. Median follow-up was 5.7 years.
Total removal was achieved in 92.33% of cases; 143 patients had incomplete resection with evidence of regrowth in 8. In the 1742 previously untreated patients, anatomic preservation of facial nerve was achieved in 1661 cases (95.35%), and House-Brackmann grade I or II was reached in 1047 patients (59.87%). Facial nerve outcome was significantly better in tumors ≤ 20 mm. Surgical complications included cerebrospinal fluid leakage in 0.85%, meningitis in 0.10%, intracranial bleeding in 0.80%, non–VII/VIII cranial nerve palsy in 0.96%, cerebellar ataxia in 0.69%, and death in 0.10%. The technical modifications that evolved with increasing experience are described.
The enlarged translabyrinthine approach is a safe and effective approach for the removal of VS. The complication rate is very low and tumor size is still the main factor influencing postoperative facial nerve function with a cutoff point at around 20 mm 8).
123 patients who underwent translabyrinthine removal of a large vestibular schwannoma (>4 cm in the cerebellopontine angle, stage IV). All surgical and medical complications and facial function were reviewed, with a 1-year follow-up.
Mortality during the first year was 0.8% (one case of infarct of the anterior inferior cerebellar artery, fatal after 8 months). In all, 4.9% of patients underwent a second surgery (for delayed hemorrhage or cerebrospinal fluid leak) during the first months after removal of a large vestibular schwannoma; 3.2% of patients experienced definitive neurologic complications (one death, one cerebellar disturbance, and two cases of 10th cranial nerve palsy) 9).
Tong MC, Lam JM, Hu BH, Sanna M. [Clinical experience in 36 cases of using of the extended translabyrinthine technique for the treatment of large acoustic neuromas]. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2005 Sep;40(9):705-7. Chinese. PubMed PMID: 16335411 10)