Beware the Alar Base Optical Illusion in Assessment of Unilateral Cleft Lip Nasal Deformity

Abstract

Sir: Dr. Mulliken has once again illustrated his vast experience and expertise in a simple yet elegant study.1 Incorrectly diagnosing a lateralized cleft alar base position can lead to medial repositioning during secondary revision, thereby worsening an existing deformity. The study by Mulliken et al. demonstrates how commonly the mistake is made and provides a simple maneuver to avoid this pitfall. The article will no doubt have an important impact on cleft care. What we find interesting is the etiology of the “optical illusion.” While aberrations of form may prompt innate human perceptions that result in an “illusion,” it is also possible that bias from surgical dogma may be at play. Our literature commonly attributes the unilateral cleft lip nasal deformity to lateral displacement of the cleft alar base and considers medial repositioning as a key component of reconstruction.2–4 As such, the medical professionals who served as raters in this study may have attributed less favorable form to “undercorrection” of the cleft alar base, resulting in more frequent ratings that the alar base was too wide. We have recently analyzed three-dimensional images of infants with unrepaired cleft lip and found that, if a vertical midway through the intercanthal line is used as reference, the medial-lateral position of the cleft alar base is normal relative to control (infants without cleft) and the cleft alar base is much closer to midline than the noncleft alar base (Fig. 1).5 After repair, medial movement of the noncleft alar base and anterior movement of the cleft alar base produced nasal base positions that matched those of normal controls. Given those findings, the current dogma is wrong: the unilateral cleft lip nasal deformity does not occur because of lateral displacement of the cleft alar base. Rather, it is the columella and noncleft alar base that are displaced laterally. Therefore, the cleft alar base should not be moved medially, otherwise the distance from alare to midline would be too narrow and the underlying etiology of the nasal tip derangement would remain (Fig. 2).Fig. 1.: Current dogma dictates that the cleft alar base is laterally displaced and needs to move medial to correct the unilateral cleft lip nasal deformity. If focused on the lower nose, the collapse and resulting deformity of the cleft alar dome captures our attention, leading us to perceive that the cleft side is displaced laterally, relative to the rest of the more normal-appearing nose. Based on three-dimensional image analysis and photographs that use medial canthi to define the facial midline, it is actually the noncleft alar base and columella that are displaced laterally. The cleft alar base is retropositioned but similar in medial-lateral position relative to that of control subjects without clefts. In order to improve symmetry, the noncleft alar base needs to move medial, the columella needs to be centralized, and the cleft alar base needs to move anteriorly.Fig. 2.: The uncorrected or inadequately corrected nasal base becomes apparent when using the full face as reference. The noncleft alar base is lateral, the columella is off midline, and cleft alar base is posterior (and not lateral). While the distance from the cleft alare to subnasale (al-sn) may be wider than the noncleft side, the distance from cleft alar base to midline is less than that on the noncleft side. Medial repositioning of the cleft alar base should be avoided, as it would make the deformity worse.It would be interesting to see if the results of Mulliken et al.’s study would be reproduced with raters who are naive to existing surgical dogma. Repetition of the study utilizing a layperson rating group or crowdsourced rating system could be utilized to this end. If the same outcome is not reproduced, the phenomenon that the authors describe may be more of a bias from erroneous surgical dogma rather than a true optical illusion (i.e., an innate misperception influenced by visual cues). Regardless of optical illusion or bias, accurate assessment of alar base position is critical. The maneuver that Dr. Mulliken’s group describes and objective analysis of three-dimensional stereophotogrammetry are valuable in avoiding a cleft alar base that is too medial. Once an alar base has been placed too medially, it is very difficult to reverse. “The eye sees what the mind knows,” and by uncovering our misperceptions, we may improve the care that we provide. PATIENT CONSENT Parents or guardians provided written consent for use of the patient’s image. DISCLOSURE The authors have no financial interest to declare in relation to the content of this communication. No funding support was received for this work. Chad A. Purnell, M.D.Russell E. Ettinger, M.D.Raymond W. Tse, M.D.Division of Craniofacial and Plastic SurgerySeattle Children’s HospitalDivision of Plastic SurgeryUniversity of WashingtonSeattle, Wash.