Taste perception after lingual nerve repair

Purpose: This retrospective study evaluates patients' perception of taste a fter lingual nerve injury and repair. It is hypothesized that return of tas te is a distinct neurophysiologic phenomenon related to specialized taste p hysiology and it does not correlate with specific, objective sensory return . Patients and Methods: During 1995 to 1996, 30 patients underwent microsurgi cal repair of lingual nerve injuries. Of these, 22 patients met the inclusi on criteria for this study. Chart review documented the date and cause of i njury, sensory examination, injury classification, procedures, operative fi ndings, and postoperative sensory examination. A telephone questionnaire ad dressed whole mouth taste perception with normal daily eating. The question s asked were: 1) Was your sense of taste changed or abnormal after your ner ve injury? and 2) Did your sense of taste recover after nerve repair:, Results: All patients had a postinjury, prerepair sensory deficit on levels A, B, and C testing: neurotmesis (n = 14); and axonotmesis (n = 8). The me an time from injury to repair was 16 weeks (range, 3 to 41 weeks). Operativ e findings confirmed 12 Sunderland Class TV (partial transection) injuries and 10 Class V (complete transection) injuries. All patients had primary mi crosurgical repair without a nerve graft or entubulization. Postoperatively , 18 patients showed marked improvement in sensory testing at levels A, B a nd C, and 4 patients showed no significant change. A telephone interview re garding whole mouth taste perception indicated that 20 of 22 patients perce ived changed, abnormal taste postinjury and pre-repair. Two patients report ed normal taste perception. Postrepair, only 7 of 20 patients reported an i ncrease or return of taste perception to a more normal level. The mean foll ow-up time was 80 weeks. Conclusion: Most patients (20 of 22) with lingual nerve injuries in this st udy perceived whole mouth taste as abnormal. After nerve repair, although 8 2% (18 of 22) of patients had improvement in somatosensory function, whole mouth taste was perceived as improved by only 35% (7 of 20). It is proposed that the perception of whole mouth taste may not be related to the ability to perceive multiple sensory modalities, but rather to special sensory (ta ste) modality perception. Also, central changes may occur in the special se nsory fibers that impact on the brainstem nucleus for taste (nucleus solita rius) and therefore the patient's perception of taste.