With only one exception, the patients with cleft lip and palate in the present study did not have normal sensation on the upper lip. For many patients the area of altered sensation was mild and restricted to the tissues traumatized during primary and secondary revision surgeries. However, for about half of the patients, it extended to the contralateral, noncleft side of the upper lip or onto the philtrum. In adults, injury and reconstructive surgery of the lips often result in a loss of sensation, which is frequently accompanied by impaired labial motor function (Stranc and Fogel, 1984
; Stranc et al., 1987
). Similar neurosensory sequelae of reconstructive surgery of the lips in children seem plausible, barring the possibility of a more complete or perfect regeneration of injured nerves in younger patients. Additionally, scar-associated alterations in tissue compliance might affect how, and which, skin receptors respond to tactile stimuli. Because of the loss of innervation, changes in tissue compliance, or both, one would predict altered sensation in cleft scars, although this has not been reported in the literature or studied previously to the authors’ knowledge. In the present study, the presence of scarring might explain why some patients described the wooden stimulus as “more scratchy” over the repaired tissues and why one patient reported that his face did not feel normal during smiling.
The findings of this study are in contrast to those of previous studies that reported no alterations in sensory function (Posnick et al., 1994a
; Uchiyama et al., 1998
; Akal et al., 2000
). Three possibilities might explain the failure to detect impairment in lip sensation. First, sensory function was evaluated at fixed skin sites only in the previous studies. Given that individual patients exhibit uniquely different repaired and scarred tissues, the specific sites tested might not have included the patients’ areas of altered sensory function.
A second plausible reason that previous studies found no sensory alterations is that only objective neurosensory testing procedures were employed (Essick, 1992
). During these conventional procedures, patients are asked to respond when, or if, they feel contact with the skin, vibration, two points of contact, warmth, pain, etc. (Essick, 1992
; Posnick et al., 1994b
; Uchiyama et al., 1998
). Their responses are accepted as accurate reflections of their sensations. These methods are preferred for measuring the absolute and differential sensitivities of sensory processing, but they are largely insensitive to how stimuli feel qualitatively on the skin (Essick, 1992
; Essick et al., 1999
). With the return of normal touch, temperature, and pain sensibilities after reconstructive lip surgery, stimuli do not always feel the same on affected skin as on the adjacent normal skin (Takahashi and Kato, 1966
). This additional insight can be obtained only by asking the patients to compare and describe the sensations evoked by the same stimuli on suspect and unaffected skin sites.
It would be informative to compare the subjective evaluations afforded by the procedures described in this article with the outcome of conventional neurosensory testing at fixed skin sites. It is possible that the patients in this study would appear to have normal sensory function based on objective testing. This issue will be addressed at the end of the longitudinal study at which time two-point discrimination and thermal threshold data will be available.
A third factor limiting the identification of sensory alteration in patients with cleft lip is their altered perception of normal sensation. That is, unless questioned carefully, patients might not recognize as abnormal those sensations they have had since infancy, particularly as sensation in the upper lip is likely to be secondary to esthetic and functional concerns. That this is the case was suggested by the findings of this study. At the beginning of the testing session, only 3 of the 16 patients responded affirmatively when questioned as to alterations in sensation. However, 15 of the 16 patients noted altered sensation in response to the stroking movements of the applicator stick during the mapping exercise. It is noteworthy that two of the three patients who initially reported alterations in sensation were girls aged 16 and 21 years. It might be that these patients had acquired better introspection skills and awareness of facial sensation from the application of facial cosmetics.
The altered sensations (both losses in sensation and hypersensitivities) reflect abnormalities in sensory information from the upper lip or in the central neural processing of that information (Essick, 1992
; Essick et al., 2002
). Sensory information from the face serves a role in proprioception, as well as in perception, and affects, for example, the manner in which speech movements are achieved (Putnam and Ringel, 1972
; Edin and Johansson, 1995
; Trulsson and Essick, 1997
; Tremblay et al., 2003
). Altered patterns of sensory information because of loss of receptors or changes in skin compliance are predicted to have a negative impact on the motor control of the face, even in cases for which speech appears normal. Such abnormalities in children with cleft lip have been demonstrated and include altered electromyographic responses evoked in the facial musculature by mechanical taps applied to the lips (D’Antonio et al., 1994
). To what extent these abnormalities contribute to clinically observable dysfunction in facial movements is unclear (Trotman et al., 2000
The relationship between altered sensation and clinically observable dysfunction is likely very complex. Of the two subjects who exhibited the most pronounced sensory alteration, one exhibited severe speech impairment (mapped area shown in ), and one exhibited near normal speech (mapped area shown in ). Interestingly, the latter subject reported that she had worked hard to learn to speak clearly. Sensory retraining, both through professional therapy and self-teaching, is a means by which young patients can learn to utilize altered patterns of sensory inputs from their lips and in doing so, minimize the presentation of functional impairment. In this regard, no disabling motor deficits were identified in the present study that could be attributed largely to loss in sensory function (Stranc and Fogel, 1984
; Essick, 1998
; Posnick and Grossman, 2000
). One such deficit, drooling, is often observed in adults after orthognathic and lip surgeries. The adults may have greater sensory impairment than young patients with cleft lip or have less capacity for sensory retraining.
Collection of the data in the present study required the cooperation, concentration, and active participation of young subjects in a clinical environment. As such, the data were necessarily biased by the cognitive skills of the individual patients and their selection and use of words to describe the impairments. The mapping data were also biased by the precise manner in which the two examiners applied tactile stimuli to the face. The consistency across subjects, however, makes evident that the major finding of this study, that altered sensation often exists in the cleft lip, cannot be attributed to these biases.
In conclusion, many patients with cleft lip and palate have areas of altered sensation on the upper lip. This is observed clinically on careful questioning of patients about the “feelings” in their lips and face. Within the scarred areas, the altered sensation can be evoked by light, brushing contact with the fingertip or the ends of a cotton-tip applicator stick. Although loss in sensation is more likely, some patients may report increased sensations of scratchiness, tingle, or tickle.