Usefulness of the Blink Reflex Study as a Preoperative Evaluation in the Orbitozygomatic Complex Fracture

PURPOSE: As the evaluation of the preoperative sensibility in the orbitozygomatic complex fracture, used by most surgeons, depends on the patient's subjective judgements, it is difficult to make generalization and to use it as an objective evaluation method. We used the blink reflex study to objectively evaluate injury to the infraorbital nerve. METHODS: From December 2008 to November 2009, a total of 16 patients underwent the patient's subjective report on sensory symptoms and the blink reflex study preoperatively. Among patients having orbitozygomatic complex fracture of type III or more according to Henderson's classification and simultaneously suspected as being injured along the infraorbital nerve pathway, patients who had difficulty in checking preoperative sensibility and said 'normal sensibility' were selected as candidates. RESULTS: Fifteen patients showed abnormal R1 on the fracture side. These results suggested that most of patients had injury to the infraorbital nerve. CONCLUSION: Contrary to the existing tests, the blink reflex study is a useful diagnostic tool in reflecting injury to the infraorbital nerve objectively.

A Study on Synkinetic Behavior in Hemifacial Spasm Using Blink Reflex Methodology

BACKGROUND AND PURPOSE: Hemifacial spasm is clinically characterized by involuntary co-contraction of unilateral facial muscles innervated by facial nerve and presence of synkinetic response between facial muscles innervated by different branches of facial nerve is considered as the electrophysiological hallmark of this disease. We performed this study in order to analyse and thereby to approach the pathogenesis of these synkinetic responses in detail. METHODS: Blink reflex test was applied to the 21 patients with hemifacial spasm. With some modification of conventional blink reflex methodology, synkinetic responses between orbicularis oculi and orbicularis oris muscles were recorded on both affected and unaffected sides. RESULTS: Among 21 patients, 10( 47.6% ) showed synkinetic responses both on affected and unaffected side, 8( 38.1% ) only on affected side, and 3( 14.3% ) did not show any evidence of synkinesis on either side. CONCLUSION: These findings could be considered as additional supportive evidence that the facial neuronal hyperexcitability is working in hemifacial spasm as synkinesis on unaffected side cannot be explained solely by peripheral mechanism. Further research on change of synkinetic behavior after microvascular decompression surgery seems to be needed.

Facial Nerve Conduction Study in Cured Leprosy Patients

Leprosy is an infectious disease caused by Mycobacterium leprae and characterized by dermal and peripheral nerve lesions. The facial nerve is also frequently involved in leprosy. There are a few electrophysiologic studies on the facial nerve involvement in leprosy patients, but there is no electrophysiologic study on the facial nerve involvement in cured leprosy patitents. So we performed facial nerve conduction study and Blink reflex study in 19 cured leprosy patients who have been managed with Dapsone for a long time. Facial motor latencies were prolonged in 11 patients(57.9%).: 10 of 15 patients in lepromatous type; 1 of 4 patients in tuberculoid type. Prolonged latencies were shown in temporal branch, zygomatic branch, buccal branch, and mandibular branch in 9(47.4%), 6(31.6%), 5(26.3%), and 3(15.8%), respectively. Blink reflex study suggests combined facial nerve and trigeminal nerve lesion in 2 patients.