Introduction: Despite the different pathophysiological mechanisms underlying Bell's palsy, in assessing severe traumatic facial paralysis, many surgeons rely on electrophysiological criteria to determine whether facial nerve exploration is warranted. To assess the value of preoperative electroneurography (ENoG) and the time of surgery, we analyzed data from three tertiary medical centers.
Materials and methods: The records of 517 patients with a degenerative ratio (DR) greater than 80% on ENoG were collected, and two groups were defined: group A (90% DR ≤ ENoG) and group B (80% DR ≤ ENoG < 90% DR). The difference in effectiveness of surgery versus conservative treatment was analyzed based on the postoperative outcome determined by the House-Brackmann grading system. The independent-samples t test was used to compare surgery with conservative treatment for each day of surgical exploration.
Result: In groups A and B, the average recovery time from facial paralysis was better in patients who had undergone surgical exploration than in those who had been treated conservatively. In group A, the difference was significant only for patients who underwent surgery within 8 days. In group B, a significant difference was found for patients who underwent surgery within 16 days but also for surgery performed 20 and 30 days after the onset of facial paralysis.
Discussion: In the surgical treatment of facial paralysis, the criteria for trauma patients should be distinguished from those of patients with Bell's palsy. In traumatic facial paralysis, some axons are more vulnerable to external collapse, and the degree of Wallerian degeneration of the peripheral nervous system will vary depending on the type of injury. The results of this study will help to identify those patients with traumatic facial paralysis who should be treated surgically and when they should be treated.
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