Endoscope-Assisted Cochlear Implantation

OBJECTIVES: Our aim was to present our endoscope-assisted cochlear implantation (CI) technique, in which the middle ear landmarks were identified through the facial recess exposure by using an endoscopic view without elevating the tympanic annulus. The secondary goal was to assess whether the situation of difficult surgical exposure could be predicted by evaluating preoperative axial computed tomography (CT) examinations. METHODS: CT examinations and surgical outcomes of endoscope-assisted CI surgeries were analyzed. RESULTS: A total of 179 CI operations performed in 27 adults (15.1%) and 152 children (84.9%) were retrospectively evaluated. It was found that in 14 cases (7.8%), endoscopic examination contributed substantially in identifying the round window (RW) membrane correctly. Endoscopic identification of the RW through the posterior tympanotomy enabled us to perform a straightforward surgery in all these cases, without the need for switching to a bony cochleostomy or alternative surgical techniques. The difficulty in the surgical exposure was predicted preoperatively by examining the axial CT scans in six of the 14 cases (42.8%) for which endoscopic assistance was necessary in order to identify the RW correctly. CONCLUSION: The main benefit of endoscope-assisted CI is the improved visibility leading to a panoramic view of the RW region. The implementation of transfacial recess endoscopic examination into the conventional CI technique is helpful to avoid problems during surgical orientation. However, the difficulty in the surgical exposure of the RW cannot be reliably predicted by the subjective evaluation of preoperative CT scans and more studies are needed to obtain reliable criteria.

The Effect of Insulin Like Growth Factor-1 on Recovery of Facial Nerve Crush Injury

OBJECTIVES: The aim of this study is to investigate the efficacy of locally applied insulin-like growth factor 1 (IGF-1) on the recovery of facial nerve functions after crush injury in a rabbit model. METHODS: The rabbits were randomly assigned into three groups. Group 1 consisted of the rabbits with crush injury alone; group 2, the animals applied saline solution onto the crushed facial nerve and group 3, IGF-1 implemented to the nerve in the same manner. Facial nerve injury was first electrophysiologically studied on 10th and 42nd days of the procedure. The damage to the facial nerves was then investigated histopathologically, after sacrification of the animals. RESULTS: In the electrophysiological study, compound muscle action potential amplitudes of the crushed nerves in the second group were decreased. In pathological specimens of the first and second groups, the orders of axons were distorted; demyelination and proliferation of Schwann cells were observed. However, in IGF-1 treated group axonal order and myelin were preserved, and Schwann cell proliferation was close to normal (P < 0.05). CONCLUSION: Local application of IGF-1 in a slow releasing gel was found efficacious in the recovery of the facial nerve crush injury in rabbits. IGF-1 was considered worthy of being tried in clinical studies in facial nerve injury cases.