Analysis of Our Treatment Protocol for Microform Cleft Lip

Microform cleft lip refers to a mild form of incomplete cleft lip. Since Brown’s report on this in 1964, there have been many reports on its diagnostic criteria and treatments. However, despite its history of more than half a century, there is still no consensus as to how far the lesion should be cut and how it should be left uncut in the operation for microform cleft lip. The usual surgical procedure in cases where reconstruction of Cupid’s bow becomes necessary is the Rotation and Advancement Method （R-A Method）. In our technique, the orbicularis oris muscle is dissected only when significant changes in the position of the muscle layer are required. However, at our hospital in the past 20 years, there was no case of full-thickness dissection of any orbicularis oris muscle. We assessed 10 cases in the past 20 years diagnosed as microform cleft lip according to Iwanami et al.’s diagnostic criteria. The cleft types of these cases were subdivided using Onizuka’s classification and Yuzuriha et al.’s classification. We analyzed the procedure of primary surgery, the presence or absence of secondary surgery, procedure of secondary surgery, and current symptoms. Postoperative results through facial photographs of the patients at their final visits were evaluated using Thomson’s evaluation criteria, with the following results. By Onizuka’s classification, there were 2 cases of Second Grade Second, and the remaining 8 cases were Second Grade Third. By Yuzuriha et al.’s classification, there were 3 cases of Minor-Form, 4 cases of Microform, and 3 cases of Mini-Microform. Incisions extending from the nostril floor to the entire length of the lips were performed in 7 cases, including 5 cases by the R-A Method. The remaining 3 patients underwent only partial incision without whole lip skin incision. In all cases, the deep muscularis was continuous and this continuity was preserved. Reconstruction of the orbicularis oris muscle was performed in 6 cases with dehiscence and thinning of the superficial muscularis, regardless of the extent of the incision. In the long-term follow-up, secondary surgery was performed in 4 cases, 6 times in total. Using Thomson’s assessment, all cases showed significant improvement post-operatively. Based on these results, it is our opinion that continuous muscularis does not require dissection of the full thickness of the orbicularis oris muscle. Furthermore, this surgical technique is considered less invasive.