Medial and Lateral Crural Overlay Techniques

Medial and Lateral Crural Overlay Techniques

Hossam M.T. Foda


Adjusting the projection and rotation of the nasal tip is considered one of the most challenging maneuvers in rhinoplasty. The nasal tip projection refers to the posterior-anterior extension of the tip from the vertical facial plane. Tip rotation is defined as movement of the tip along an arc, with its radius maintained from the facial plane. Techniques modifying the alar cartilage can result in predictable changes in the degree of projection and rotation; these changes can be maintained only in the presence of an adequate amount of tip support.

Important mechanisms that provide support and maintain the degree of projection and rotation include the ligamentous attachment of the medial crural footplates to the caudal septal cartilage, the fibrous attachment between the upper and lower lateral cartilages, and the interdomal ligament that spans over the anterior septal angle. However, the major support of the nasal tip is derived from the alar cartilages themselves, namely, from the length and strength of the medial and lateral crura.

Techniques for repositioning the nasal tip can be divided into two categories: those that modify the existing alar cartilages and those that augment the nasal lobule with grafts or implants.

In cases where the alar cartilages are overdeveloped with long medial and lateral crura, adequate tip repositioning is practically impossible without decreasing the size of the alar cartilages.

In the 1930s, Joseph and Safian first described shortening of the medial and lateral crura to deproject the nasal tip. Since then, many refinements of shortening the lateral crura were described to preserve vestibular skin and to suture or overlap the divided segments. Later, Lipsett pioneered medial crural shortening in 1959; since then, many refinements of the procedure have been described. In the current chapter, I will present my experience in shortening the medial and lateral crura using the medial crural overlay (MCO) and lateral crural overlay (LCO) techniques.

Both the tripod concept described by Anderson in 1969 and its recent modernization into the M-arch model by Adamson are very helpful in comprehending the effects that alar cartilage-modifying techniques have on the degree of tip projection and rotation. The tripod concept depicts the alar cartilages as a tripod, with two upper legs formed by the lateral crura on each side and one lower leg formed by the conjoined medial crura. Applying the tripod analogy, the LCO, carried out alone (Fig. 20.1, top), will shorten the upper legs of the tripod which will move the tip backward and upward, thus decreasing projection, increasing rotation, and shortening the nose. MCO, carried out alone (Fig. 20.1, bottom), will shorten the lower leg of the tripod that will move the tip backward and downward, resulting in a decrease in projection, inferior rotation, and increase nasal length. Combining LCO with MCO (Fig. 20.1, center) will result in additional deprojection without altering the degree of rotation.

Furthermore, an equal amount of shortening of the M-arch may produce variable yet predictable changes in projection and rotation, depending on where the arch is shortened. For example, shortening the medial crura causes deprojection and counterrotation, whereas shortening the lateral crus causes deprojection and rotation. Shortening the intermediate crus can cause a variable degree of deprojection and rotation depending on where
the vertical division and overlap is performed. If done near the angle, at the junction of the medial and intermediate crus, there is more deprojection and less rotation. If done closer to the apex of the alar arch, there is more rotation and less deprojection.

FIGURE 20.1 Schematic illustration of the effects of shortening lateral and medial crura on the degree of tip projection and rotation. Top: LCO decreased projection and resulted in superior rotation. Bottom: MCO decreased projection and resulted in inferior rotation. Center: The combination of LCO and MCO resulted in deprojection with no change in rotation.


A general review of the medical history is performed in relation to neurologic, cardiovascular, pulmonary, autoimmune, and overall physical fitness. Review of medications, anticoagulation therapy, tobacco and substance abuse is discussed as well. Prior to any rhinoplasty, one should exclude patients with a history of emotional problems or nervous breakdowns. A good history of nasal problems is mandatory stressing previous nasal
trauma or nasal surgery and the detailed nature of these surgeries by reviewing all available operative data and analyzing the patient’s photos before and after each of the previous surgeries. Finally, a complete detailed history of the patient’s nasal complaint, both aesthetic and functional, is performed.


The vital part in planning for a rhinoplasty is to fully understand the patient’s desires and objectives; this is greatly helped by performing computer imaging as the surgeon can monitor the patient’s reaction to the modifications in the degree of tip projection and rotation. On evaluating the degree of tip projection, it is important to exclude factors that may cause an illusion of overprojection, such as a deep nasofrontal angle, marked dorsal saddling, receding chin, or short upper lip. Once true overprojection is determined, the next step is to detect if its overprojection is due to overdeveloped alar cartilages (primary), septal cartilage (secondary), or a combination of both. When the septal cartilage is the main cause for the overprojection, the deformity is referred to as “tension nose” (Fig. 20.2) and is characterized by a high anterior septal angle and overdeveloped caudal septum and/or anterior nasal spine. Correction of the “tension nose” requires elimination of the pedestal effect of the overdeveloped septum on the normal alar cartilages which can now fall backward to a less projected position. This can be achieved through volume reduction of septal cartilage and rarely the anterior nasal spine. In cases of primary overprojection, where the main cause of overprojection is the overdeveloped alar cartilages with long medial and lateral crura (Fig. 20.3), adequate deprojection is only possible through shortening the crural length by MCO, LCO, or both. The choice depends largely upon whether rotation is adequate or will need to be increased or decreased. The droopy, inferiorly rotated tip which occurs in approximately 75% of my rhinoplasty patients is a much more common finding than the superiorly rotated tip. The pathogenesis of the droopy tip may be divided into two groups. The first group has “abnormal” alar cartilages with excessively long lateral crura, vertically malpositioned lateral crura with high abutment to the pyriform aperture, or short, weak medial crura. The second group has “normal” alar cartilages which are displaced inferiorly by the effect of extrinsic forces. These forces may be pushing from above, as in cases with long upper lateral cartilages, high anterior septal angle, and overdeveloped caudal septum, or forces pulling from below, as in cases with thick heavy nasal skin, overactive depressor septi nasi muscle, or by the effect of gravity on cases with weakened tip support as a result of aging or previous operations. The first step in the management of the droopy tip is to eliminate any

extrinsic forces pushing the tip downwards, thus allowing the alar cartilages the freedom to move upward, during the healing phase, and to rest in a more cephalic orientation. This is possible through such maneuvers as excision of overdeveloped scrolls of upper lateral cartilages, cephalic trim of lateral crura, lowering the anterior septal angle, or weakening of the depressor septi muscle. These maneuvers may be sufficient in cases with mild degrees of droopy tip. However, cases with more advanced degrees of droopy tip can only be corrected by alar cartilage-modifying techniques aiming at shortening the lateral crura as in LCO.

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Oct 7, 2018 | Posted by in OTOLARYNGOLOGY | Comments Off on Medial and Lateral Crural Overlay Techniques

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