Extended Mohler Unilateral Cleft Lip Repair

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Extended Mohler Unilateral Cleft Lip Repair

Roberto L. Flores, Court B. Cutting

KEY POINTS

The apex of the Mohler back-cut should be placed on the columella at least 1.5 to 2 mm superior to the base of the nose. Novice surgeons often underestimate the vertical height of this critical mark. The columellar scar is nearly imperceptible; therefore concern should be limited regarding the effect of this incision on columellar appearance.

The L-flap should be based on the lateral nasal wall and not the alveolus, as originally described by Millard. An alveolar-based L-flap will create a nasolabial fistula.

The addition of a Noordhoff triangular flap of vermilion will help to prevent notching and to restore fullness to the medial lip vermilion.

The best time to close the floor of the nose is during cleft lip repair; therefore this should be attempted in every case.

Presurgical orthopedics in the form of nasoalveolar molding and other techniques provides assistance in making cleft lip repair more predictable and reliable.

Tension-free transposition of all soft tissue elements should be confirmed before closure. If tension is present at the time of closure, the deformity will relapse.

Primary cleft rhinoplasty is critical to aesthetic and functional results; however, excessive dissection should be prevented, because it may be prohibitive to predictable rhinoplasty in the future.

In 1987, Lester Mohler, a plastic surgeon in private practice in Columbus, Ohio, described a variation of Ralph Millard’s rotation-advancement reconstruction of the unilateral cleft lip in which the back-cut was relocated from the upper lip to the columella. A C-flap, rather than a lateral lip, was used to fill the skin defect created by the downward rotation of the Cupid’s bow, and the resulting scars ran exactly along the subunit borders of the upper lip. The extended Mohler repair, a modification of the classic Mohler reconstruction, can be successfully applied to any unilateral cleft lip deformity, regardless of severity or use of presurgical orthopedics. This modification has led to more widespread acceptance of Mohler’s surgery, which remains one of the most common techniques used for unilateral cleft lip repair. This chapter also describes our preferred methods of primary rhinoplasty, vermilion reconstruction, L-flap modification, and other techniques, because they complement the extended Mohler repair and help to optimize surgical outcomes.

HISTORY

The principles of the Millard rotation-advancement technique are described elsewhere in this text; however, a brief review of the Millard reconstruction is necessary to understand the evolution and advantages of the extended Mohler repair.

The principle of the rotation-advancement repair was founded on the realization that the Cupid’s bow is preserved in patients with unilateral cleft lip deformities.1,2 Therefore, Millard reasoned, the downward rotation of the medial lip element as a near-total unit could be accomplished by an upper lip incision along the lower two thirds of the philtral line on the cleft side, adding a back-cut at the superior aspect of the lip, beneath the columella. The Cupid’s bow, philtral dimple, and most of the philtral column were preserved by this procedure. The medial lip element was elongated by the downward rotation of the medial lip composite, and the defect created by this downward rotation was filled by medial advancement of the lateral lip element. Millard’s rotation-advancement principle was a distinct advantage over the Tennison-Randall method, which violated the philtral dimple with a triangular scar.3,4

Millard’s rotation-advancement repair revolutionized unilateral cleft lip reconstruction; however, the limitations of this technique led to further modifications in an effort to improve surgical outcomes. The design of Millard’s medial lip incision violates the aesthetic subunit borders in the superior third of the lip by curving the rotation scar medially, toward the nasal floor on the unaffected side. This asymmetry is more apparent in children with wide clefts, who often require a significant downward rotation of the Cupid’s bow. Another limitation is the use of the lateral lip element to fill defects created by the downward rotation of the Cupid’s bow. As a result, medial transposition of the alar base is determined by the defect of the medial lip element rather than by the degree of displacement of the alar base. In cases of a severe deformity, associated with a foreshortened upper lip, a significant amount of medialization of the lateral lip element is required, sometimes resulting in the creation of a micronostril, a nasal deformity that lacks a reliable means of reconstruction. In attempts to separate the alar base transposition from the lateral lip transposition, incisions have been extended around the alar base along the alar-facial groove; unfortunately, scars in this area heal rather poorly.

In Mohler’s variation of the Millard repair (Fig. 44-1), Millard’s classic markings are followed; however, the back-cut is placed onto the columella instead of across the upper lip.57 The resulting scar follows the entire line of the philtral column, with the addition of a small horizontal scar at the base of the nose. This final scar pattern respects the subunit principle of the upper lip. In Mohler’s original design, the back-cut extends only to the middle of the philtral dimple; this rather small back-cut provides a limited degree of downward rotation of the Cupid’s bow. Millard accurately criticized Mohler’s original description of his columellar back-cut as being inadequate for use in complete clefts and likely useful only in incomplete clefts.8 To apply the full potential of the columellar back-cut, the apex of the Mohler incision was extended to just beyond the midline of the columella. The back-cut was then brought down to the opposite philtral column, but no farther6,7 (Figs. 44-2 and 44-3). This modification of the original design allows for full downward rotation of the Cupid’s bow in any unilateral cleft lip patient, regardless of severity.

In Mohler’s repair, the C-flap, rather than the lateral lip element, is used to fill the defect created by the downward rotation of the Cupid’s bow. Because the defect created by the downward rotation of the Cupid’s bow remains entirely within the columella, the C-flap is predominantly used for columellar elongation, rather than the addition of tissue to the upper lip. Because the lateral lip element is not used to fill the defect created by the downward rotation of the Cupid’s bow, less medial advancement of the lateral lip element is generally required, decreasing the risk of creating a micronostril. Moreover, no differential degree of advancement occurs between the lateral lip element (to fill the downward rotation of the Cupid’s bow) and the alar base (to create an aesthetic and balanced nostril). Therefore separating the lateral lip from the ala with an unaesthetic perialar incision is unnecessary. A short, near horizontal incision at the alar base is all that is needed.

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Fig. 44-2 Markings of the extended Mohler repair modified from Mohler’s original design. The apex of the back-cut is drawn 2 mm up on the columella and approximately four sevenths across the columella toward the noncleft side. The base of the back-cut extends to but not beyond the philtral column on the noncleft side. The incision down from the apex of the back-cut extends to just outside the Cupid’s bow point as a nearly straight line. The C-flap is wider than Mohler’s original design. A Noordhoff vermilion flap has been added to the design. Note that the nostril floor has not been used to lengthen the vertical height of the lateral lip element and that a perialar incision is not used.

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Fig. 44-3 Digital rendering of the extended Mohler repair. The C-flap is used to fill the defect created by downward rotation of the Cupid’s bow. As a result, the lateral lip element is advanced to the philtral line on the cleft side but not farther. This prevents the creation of a micronostril by overmedialization of the lateral lip element skin. Inclusion of the nasal floor skin on the lateral lip flap is not necessary, nor is making an incision around the alar base. The resulting scars respect the subunit borders of the upper lip.

Millard did appreciate the use of the C-flap to elongate the columella and to fill the defect created by the downward rotation of the Cupid’s bow. Millard’s evolution of the C-flap demonstrated a transition in the use of the C-flap from reconstructing the nasal floor to partially filling the defect created by the downward rotation of the Cupid’s bow (Fig. 44-4). This occurred during the development of his primary rhinoplasty technique, in which the C-flap was used to elongate the columella and elevate the depressed crural footplate on the cleft side, the latter aided by a hemimembranous septum incision.2,9 However, Millard’s C-flap was never used to fully fill the defect created by the downward rotation of the Cupid’s bow, and the signature advancement of the lateral lip element remained as part of the rotation-advancement reconstruction.

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Fig. 44-4 Final closure of the Millard repair. The C-flap is used to reconstruct the columella and nasal floor, but the lateral lip element is still used to fill the defect created by the downward rotation of the Cupid’s bow. Advancing the tip of the lateral lip flap to the opposite philtral column violates the subunit borders of the upper lip. The tiny white roll flap from the lateral lip has been inserted into a small back-cut made for it on the white roll of the medial lip element.

RECONSTRUCTIVE PRINCIPLES

The extended Mohler technique can be applied and modified to any complete unilateral cleft lip deformity regardless of severity or use of presurgical orthopedics. Several authors have stressed, however, that presurgical orthopedics such as nasoalveolar molding (NAM) can make cleft lip repair, as well as primary rhinoplasty, more predictable.1012 The final scars of the extended Mohler repair fall along the philtral line and base of the nose, preserving the subunit borders of the upper lip. The vertical scar on the columella is virtually imperceptible and is rarely noticed by patients or their families.

In circumstances in which the alar base is significantly displaced in the lateral, posterior, and inferior position, a piriform aperture incision can aid in anatomic relocation of the alar base. The L-flap has a critical role in filling the mucosal defect created by the piriform aperture incision. Reconstruction of the intranasal lining prevents secondary contracture of the nasal mucosa and relapse of the alar base deformity. In Millard’s original description, the L-flap is based on the superior alveolus, creating a nasolabial fistula at the completion of the surgery.2 To prevent formation of this fistula, the inferior incision line of the L-flap is extended beyond the alveolus and into the base of the lateral nasal wall.7,13 The L-flap can then be dissected free from the alveolus and all intraoral attachments, basing its blood supply from the mucosa of the lateral nasal wall. This modification prevents oronasal fistula formation and aids in gingivoperiosteoplasty and future alveolar bone grafting (Fig. 44-5).

The markings on the lateral lip element skin vary from Millard’s original design. Rather than following the border of the vermilion with the upper lip skin, the incision transects the white roll in a perpendicular fashion just medial to the tattoo point, then quickly turns to meet the junction of the superior limit of the white lip with the vermilion. This modification prevents peaking of the white roll, a deformity that was addressed by Millard in his white roll flap.2,9 In addition, the lateral lip skin is vertically elongated by the soft curve of the lateral lip element incision. Critics note that the vertical dimension of the upper lip is elongated at the price of upper lip width; however, studies have confirmed that the foreshortened horizontal dimension of the upper lip corrects over time.14,15

May 11, 2019 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Extended Mohler Unilateral Cleft Lip Repair
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