The Smile Index: Part 2. A Simple, Prognostic Severity Scale for Unilateral Cleft Lip

Plast Reconstr Surg. 2019 Apr;143(4):790e-797e. doi: 10.1097/PRS.0000000000005432.


Background: There is no universally accepted classification system for unilateral cleft lip that objectively quantifies the spectrum of disease, making it difficult to evaluate postoperative outcomes in the context of preoperative severity.

Methods: Anthropometric measurements and photographs were prospectively collected from unilateral cleft lip patients in Morocco, Bolivia, Vietnam, and Madagascar. Columellar angle, cleft width, nostril widths, vertical lip heights, and horizontal vermillion lengths were measured preoperatively and postoperatively. "Unacceptable" postoperative outcomes were defined as those with a cleft-side/non-cleft-side vertical lip height discrepancy greater than 3 mm, based on previous sociologic and cleft outcome studies.

Results: Of the 147 patients studied, 22 had unacceptable outcomes. Univariate logistic and multivariate logistic stepwise models showed that among preoperative characteristics, cleft width ratio (preoperative cleft width divided by commissure width) was the most significant predictor for unacceptable outcomes, controlling for surgeon experience. Cleft width ratio was normally distributed. Two severity categories were created based on iterative data and regression analysis: "severe" (cleft width ratio >0.5) and "not-severe" (cleft width ratio <0.5). Severe patients had a higher likelihood of unacceptable outcomes versus not-severe patients (OR, 2.9; 95 percent CI, 1.1 to 7.7; p = 0.029; 27 percent versus 11 percent). The probability of having unacceptable outcomes for severe individuals was higher versus not-severe individuals (positive predictive value, 73 percent versus 89 percent).

Conclusions: Preoperative cleft width ratio greater than 0.5 is associated with having an unacceptable surgical outcome. The authors propose a simple, objective, and clinically reproducible scale to unify the language of unilateral cleft lip severity, as a step toward improving algorithms of care, directing surgical technique, guiding patient/family discussions, and optimizing patient outcomes.

Clinical question/level of evidence: Risk, III.

MeSH terms

  • Cleft Lip / physiopathology
  • Cleft Lip / surgery*
  • Female
  • Humans
  • Male
  • Postoperative Care
  • Preoperative Care
  • Prognosis
  • Severity of Illness Index*
  • Smiling*