Clinical And Experimental Study Of Surgical Treatment On Facial Nerve Injury

Objective:Facial nerve trauma commonly develops during oral and maxillofacial surgery which may severely and adversely affect daily life and social contact.We aimed to retrospectively evaluate the outcomes of peripheral facial nerve paralysis caused by various conditions and treated by surgery,focus on the challenging damage situations,propose and confirm the therapeutic effect about new treatment managements.Methods:Part One:We retrospectively analyzed 42 cases of intraparotid facial nerve schwannoma(IFNS)patients and 26 patients who had received facial nerve reconstructive surgery whose injury factor was IFNS,their clinical manifestations and facial nerve function prognosis were recorded and analyzed.Part Two:We retrospectively analyzed 383 patients who received facial nerve reconstructive surgery,their clinical manifestation and facial nerve function prognosis were recorded and analyzed.Part Three:Masseteric-facial nerve transfer was applied on 20 patients whose proximal end of facial nerve was untraceable,their clinical manifestation,facial nerve function,symmetry and donor site complications were recorded and analyzed.Part Four:We conducted an animal experiment to study the effect of low-level laser therapy(LLLT)on end-to-side neurorrhaphy at rat peripheral nerve injuries repairing model.Results:Part One:IFNS mostly presented a hard-textured mass with limited mobility.Facial nerve outcomes differed significantly based on different surgical methods used and tumor involvement.Part Two:Facial paralysis caused by trauma,and nerve branch injury were more common,accompanying the primary reconstruction of facial nerve,they were predictive of favorable treatment outcomes.Part Three:Masseteric-facial nerve transfer was effectively and improved facial reanimation,post-surgery facial symmetry had limited difference in comparison with normal people,with limited donor site complications.Part Four:End-to-side neurorrhaphy was effective on nerve regeneration,but results in LLLT group had no significant difference in comparison with none-LLLT group.Conclusions:Part One:Preoperative diagnosis of IFNS remains confusing.A hard-textured tumor with limited mobility mass in the parotid gland should prompt the diagnosis of a schwannoma.FNAC is likely to be the most promising examination technique for diagnosis.Facial nerve preservation should always be essential,and stripping surgery or intracapsular enucleation could be the preferred surgical methods of choice.Part Two:Facial nerve injury caused by trauma was more likely,cases of interference in facial expression could be limited,so did the injury to branches.Nerve anastomosis was prioritized if tension-free suture was possible.Maintaining the integrity of the nerve,and shortening the duration of mimetic muscular denervation were crucial.Part Three:Masseteric-facial nerve transfer was effectively and efficiently improved facial reanimation and facial symmetry,with limited donor site complications.Part Four:Under the conditions of this experiment,end-to-side neurorrhaphy was effective on nerve regeneration,but LLLT couldn't improve its nerve fiber regrowth rate.Surgical treatment is still with significance on managing facial nerve injury,combining with experience and new method,ideal treatment algorithm could be provided.