Nasal Sculpting: Calculated and Predictable Tip Elevation With Cephalic Trim

Anatomy

A complete presentation of all the nasal elements is beyond the scope of this article. We focus primarily on the tip structures as they relate to tip position and rotation.

The medial, middle, and lateral crura and accessory cartilages make up the LLC and form scaffolding for the nasal tip. Fibrous attachments connect these elements to each other, the piriform aperture, and to the upper lateral cartilages. These fibrous attachments in conjunction with the lower and upper lateral cartilages, piriform aperture, and caudal septum form the basis for tip position.^2,3 In addition to the skin and bony structures, the nasalis muscles and the depressor septi nasi muscles can also contribute to tip animation and position.⁴ The size and shape of the LLC may also produce nasal tip asymmetries.⁵ The strength and attachments of the LLC also have been shown to impact the position of the nasal tip.^6-8 Alterations in these elements will adjust the position of the tip.

The “tripod concept” simplifies these anatomical elements. The nasal tip can be described as a tripod of 3 cartilaginous legs. With the patient upright, the tripod is formed with 1 inferior leg and 2 superior legs; the lower leg is formed by the medial crura, and the lateral crural complexes form the upper legs with attachments to the piriform aperture (Fig 2).^2,6,7,9-12 As a result, adjusting the length of any of these structures will alter the position of the tip.

Figure 2. Illustration of the cephalic trim technique altering tip position. Reprinted from Gunter and Hackney.2

Facial metrics

Preoperative planning in rhinoplasty is essential for optimizing outcomes. The surgeon needs to assess all the facial elements when planning rhinoplasty. The goal of rhinoplasty is to create harmony with all the elements of the face.¹³ Several measurements have been developed using anatomical landmarks to identify ideal facial aesthetics. Some suggest that the face can be divided into 3 equal portions, with the distance from nasion to nasal base equaling the distance from hairline to nasion and nasal base to gonion.¹⁰ The Frankfort plane is a line that passes through the inferior borders of the orbital rim (orbitale) and the upper margin of the auditory meatus (porion) and is used to determine the NLA. Several studies describe the ideal NLA as 95° to 100° in men and 100° to 110° in women^9,14-19 In addition, some have advocated slight variations in these parameters for patients of varying ethnic backgrounds.^15,16,20-24 Aesthetic ideals have also been established for the position of nasion and the nasal radix.^25-27

Most surgeons use the NLA as a parameter for measuring and adjusting tip position. However, other metrics such as the columellar facial angle and the nostril axis have also been used for quantifying tip rotation.^14-16,28 Care must be taken to not confuse the columellar-labial angle with the NLA. The columellar-labial angle is the angle between the columella and the upper lip. Using this angle can lead to a false sense of the true tip position in cases where there is a pronounced caudal septum or nasal spine.⁹

Techniques for rotation

The rhinoplasty surgeon faces tremendous variation not only in patient anatomy but also in desired patient outcomes. Not all patients require or desire the same amount of tip rotation. In addition, not all patients possess the adequate anatomical elements to employ solely one technique to alter tip position. After analyzing the entire nose and face and understanding the patient's wishes, the rhinoplasty surgeon can then employ the appropriate technique(s) to adjust the nasal tip.

Basic strategies focus on removing impediments to movement and rotation and stabilizing the cartilages once in the desired position.⁹ Some techniques used to correct the nasal tip include cephalic alar trim, suture reshaping and repositioning of the cartilages, vertical transection of the medial and lateral crura, resection of the caudal septum, insertion of tip grafts and struts, and insertion of alar strut and spreader grafts.² Previous studies have outlined algorithmic approaches to delineating techniques to alter and define the nasal tip.²⁹ The rhinoplasty surgeon typically selects from one or a combination of these techniques to achieve an aesthetically pleasing outcome.

Our study focuses on essentially one strategy to elevate the nasal tip—cephalic alar trim. While many techniques exist and are commonly used in combinations, we elected to observe how much the nasal tip would rotate purely by cephalic alar trim. As is the case for any surgical therapy, preoperative planning is essential to good outcomes. The observations from this study can help determine preoperatively whether other strategies need to be employed to achieve the desired result.

In performing the fresh tissue dissections, we used the closed cartilage delivery technique whereby marginal and intercartilagenous incisions are made to deliver the lateral cartilages. While the criticism of this technique has been that it distorts the cartilages, it does, however, allow for direct exposure and precision of resection.^2,14 The open technique provides the best exposure to all the nasal elements; however, it potentially disrupts them as well.³⁰ In addition, it has been suggested and demonstrated in previous anatomic studies that open techniques may result in a decreased nasal tip projection.³¹ As we intended to determine the effects of the change in one element, we adopted a technique that would best isolate manipulations to the alar cartilages.

Our aims were to determine the degree to which cephalic alar trim affects tip rotation. The clinical endpoint to this would be to aid surgeons in predicting how much the tip of the nose will elevate with a specific cartilage resection and thereby help plan their operation.

This type of cadaveric study has some intrinsic drawbacks. Although we used fresh cadavers from the University of Louisville Fresh Tissue Lab, the skin and soft tissues lack the elasticity and wound-healing capabilities of live tissue. These properties are inherent to rhinoplasty and likely to affect tip position. It was for this reason that we also employed a closed technique and did not close the incisions so as to disrupt as few elements as possible. In addition, it does not seem possible that such a study could be undertaken with live patients. While similar techniques are employed in the ethnic nose job, the degree to which the angles will change may be different with different ethnicities. Similarly, the cleft nose may respond differently. These drawbacks have been described in previous anatomical studies pertaining to rhinoplasty.³¹ (However, these results are not inconsistent with the practical experience of the senior authors, Wilhelmi and Florman.)