Akademik Veri Yönetim Sistemi
Türk Otolarengoloji Arşivi, cilt.57, ss.2, 2019 (Hakemli Dergi)
Objective: Damage of the facial nerve (FN) is a common outcome after a trauma and resulting functional problems have an adverse effect on the quality of life. Despite the various surgical techniques, it is difficult to completely correct the condition and additional treatment methods are needed to enhance recovery. This study aimed to investigate the efficacy of platelet-rich fibrin prepared in titanium tube (T-PRF) as an agent enhancing healing in full-thickness cut wounds of the facial nerve.
Methods: Twenty-seven New Zealand rabbits were used in the study. The rabbits were divided into three experimental groups, the Sham group (Group 1), the Suture group (Group 2), and the Suture + T-PRF group (Group 3), and the study was performed on the right facial nerves of rabbits. The number of subjects in the three groups were determined as 7-10-10 respectively; however, two subjects from each of Groups 1 and 2 died during the study and the experiment was completed with 5, 8 and 10 subjects. In the Sham group, the facial nerve trunk was dissected from the surrounding tissues and the skin was closed without further surgical intervention. In the Suture group, a full-thickness incision was made on the facial nerve trunk and the nerve endings were anastomosed with suture. In the Suture + T-PRF group, a full-thickness incision was made on the facial nerve trunk. After the nerve endings were anastomosed with suture, the T-PRF membrane was wrapped around the damaged area. Following the operation all subjects were weekly monitored for corneal reflex, vibrissae movement and lowered ear. Bilateral facial electromyography (fEMG) was performed before the operation and in the 1st, 3rd, 5th, 7th and 10th weeks after the operation, and tissues were harvested for histopathologic examination in the 10th week. Intra- and inter-group comparisons were performed.
Results: In functional evaluation, the results of the Sham group were consistently found significantly better than those of the Suture and Suture + T-PRF groups. Although improvement was seen in the corneal reflex of the Suture and Suture + T-PRF groups compared to the initial postoperative weeks, no significant differences were observed between the two groups in terms of corneal reflex in weekly follow-ups. In the Suture + T-PRF group, noticeable vibrissae movement was observed in the eighth week, one week earlier than the Suture group. While lowered ears recovered in the seventh week in the Suture group, this recovery was observed two weeks earlier, in the fifth week in the Suture + T-PRF group. In electrophysiologic evaluation, compound muscle action potential (CMAP) maximum amplitude levels and CMAP amplitude levels triggered by supra threshold stimuli were found significantly low in the Suture and Suture + T - PRF groups after the injury, however, recovered over time. In the Suture + T-PRF group, CMAP maximum amplitude levels were significantly lower compared both to their own preoperative levels and to those of the Sham group in all weeks. Nerve conduction rates did not significantly differ among the groups in the weeks before and after the injury. The nerve stimulation threshold required to trigger CMAP significantly increased after the surgery in the Suture + T-PRF group compared to their preoperative control levels. In the Suture + T-PRF group these levels regressed two weeks earlier than those of the Suture group, reaching levels comparable to the preoperative levels in the fifth week. In histopathologic examination, the Sham group had significantly better results than the two other groups. While less edema and vacuolization were observed in the Suture + T-PRF group compared to the Suture group, the difference was not statistically significant. Myelin sheath thickness did not significantly differ between these two groups.
Conclusion: In our study, T-PRF application partially accelerated functional recovery, but did not contribute to nerve conduction rates, CMAP maximum amplitude levels and CMAP amplitude levels triggered by supra threshold stimuli. It was observed, however, that it contributed to an earlier recovery in the supra threshold stimuli levels required to trigger CMAP. It was seen to tend to reduce edema and vacuolization, and no contribution to myelin sheath thickness. Further, longer-term follow-up studies should be carried out to better assess the effects of T-PRF on nerve rehabilitation.