Predictors of Trigeminal Nerve Neurosensory Deficit Following Alloplastic Temporomandibular Joint Replacement

Abstract

The purpose of this study was to identify factors associated with trigeminal nerve injury following alloplastic temporomandibular joint (TMJ) replacement. The sample included subjects who underwent alloplastic TMJ replacement surgery from 2010 through 2019 at the University of Texas Health Science Center at San Antonio. Operative interventions consisted of TMJ reconstruction with patient-fitted total joint replacement (TMJ TJR) either with or without orthognathic surgery. Eligible subjects included those who were evaluated for a neurosensory deficit at longest follow-up with a follow-up time of at least 6 months. The primary outcome variable was a neurosensory deficit (NSD) (i.e., trigeminal nerve sensory deficit, yes or no) defined as a score of greater than 0 on a Likert scale from 0-4 (0 = no deficit, 4 = complete deficit). Outcome variables were categorized as demographic, anatomic, and operative. Descriptive and bivariate statistics were used to identify associations between the predictor and outcome variables. P < .05 was considered statistically significant. A total of 346 joints were replaced within the defined temporal period. Of those, 176 met the necessary criteria to be included in the sample. Twenty-three subjects had unilateral TMJ TJR while 75 had bilateral replacement. Of the 98 subjects, 28 (29%) had a maxillary osteotomy in addition to the TMJ TJR. The mean age at the time of the operation was 38 + 18 years (min: 16, max: 79), and the majority of the subjects were female (n = 92, 94%). At the immediate follow-up appointment, 50 (51%) NSDs were reported, 16 of those fully recovered by the time of the longest follow-up (mean: 23 months). The maxillary division (V2) was involved in 21% (n = 7) of cases, the mandibular division (V3) in 44% (n = 15) of cases, and both divisions were involved in 35% of cases (n = 12). Specifically, the lower lip was the region most often affected. The prevalence of an NSD was significantly greater in subjects who underwent TJR with concomitant orthognathic surgery (n = 28, P = .036) compared to TJR alone (n = 70). Additionally, subjects with the diagnosis of degenerative joint disease (51%) had a statistically significant higher risk of trigeminal nerve deficits compared with all other diagnoses (P = .049). Age and gender were not statically correlated with prevalence of an NSD. Many patients undergoing alloplastic TMJ replacement who report a trigeminal nerve injury completely recover by the time of longest follow-up. A persistent NSD is associated with temporomandibular joint pathology and the extent of the operative procedure performed.