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.