Objectives: To evaluate the use of the retrolabyrinthine approach (RLA) combined with endoscopy with particular reference to preservation of cranial nerve function and completeness of excision in surgery of epidermoid cysts.
Methods: A retrospective study was performed on a series of 8 consecutive patients of whom 7 have undergone surgery. Main outcome measures Measures include audiological and neurological status preoperatively and postoperatively, size of the lesion, the surgical approach, completeness of excision, and operative morbidity.
Results: The tumors were all large, ranging from 2 x 3 cm to 6 x 6 cm. Presenting symptoms were headache (75%), dysequilibrium (62%), trigeminal nerve palsy (38%), abducens nerve palsy (25%), and, rarely, auditory symptoms. Seven patients underwent surgery, 5 by the RLA, 1 by a translabyrinthine approach (TLA), and 1 by a transcochlear approach. Complete excision was achieved in 5 of the 7 patients. A transtentorial approach was combined in 2 cases (1 RLA, 1 TLA). Endoscopy was used in 3 cases. It allowed a complete tumor excision. One case of keratinous meningitis was observed. Trigeminal nerve function returned to normal in all patients. Postoperative facial nerve function was grade I in 5 cases and grade III in 2 cases. Hearing was preserved in 3 cases as class A, 1 case as class B. In the 2 cases presenting with abducens nerve palsy preoperative symptoms were initially aggravated before returning to normal function by 1 year postoperatively. The RLA with endoscopy allowed less invasive surgery and preservation of hearing in 4 of the 5 cases where it was attempted. Tumor control appeared better than with the suboccipital approach. Mortality and postoperative morbidity also appear reduced.
Conclusion: RLA combined with endoscopy should be considered as the standard approach for excision of epidermoid cysts. Extension of this approach into a TLA or transcochlear approach will depend on preoperative difficulties and preoperative hearing.