An updated diced cartilage fascia technique for dorsal augmentation in rhinoplasty

The aim of this paper is to discuss an updated technique for dorsal augmentation during rhinoplasty using diced cartilage wrapped in fascia. The usage of diced cartilage has been variously described in the literature with consistently satisfactory results. Herein, we present our experience with patients undergoing dorsal augmentation during rhinoplasty using an updated method of diced cartilage wrapped in fascia. Diced cartilage fascia techniques have become the technique of choice for dorsal augmentation for an ever-increasing number of rhinoplasty surgeons. The term is broadly descriptive and there remains a wide-range of ways to execute. Updating and enhancing the technique with greater attention to precision, and creating an aesthetically optimal and predictable result, may result in even improved outcomes for future patients.


INTRODUCTION
In the practice of medicine, the concept of the "gold standard" refers to the best available test or treatment under reasonable conditions. Given the relative lack of purely objective experimentation and testing in rhinoplasty, no such criterion standard yet exists for dorsal augmentation. In the ongoing pursuit of the optimal technique for augmenting the dorsum during primary and revision rhinoplasty, surgeons have continuously sought to increase precision, safety, and permanence.
While many contemporary surgeons favor autologous grafts in an onlay configuration for mild to moderate amounts of dorsal augmentations [2,10,20] , cases demanding a larger volume of graft materials have prompted surgeons to explore alloplastic (silicone, Goretex, etc.) and homoplastic (irradiated costal cartilage) options in addition to autologous options given the ease of obtaining grafts, and the absence of any donor site morbidity [2][3][4][5] . However, a primary downside of these grafts has proven to be the relatively high risk of complications compared to autologous graft techniques, driving other surgeons to pursue this avenue more intently.
The use of diced cartilage in dorsal augmentation has been periodically documented in the Englishlanguage literature as early as 1943 by Peer, in 1951 by Cottle, and in 1968 by Burian, though it did not gain wide-spread acceptance at the time [21][22][23] . Guerrerosantos revisited this concept in the 1990s [8] , refining the technique by wrapping fragmented cartilage in fascia, while Erol brought a larger audience with his description of wrapping diced cartilage in Surgicel in 2000 [24] , then Daniel subsequently brought a renewed interested in wrapping diced cartilage in fascia [6,7] . Modifications of the concept of using diced cartilage as the building block for dorsal augmentation have been variously described, primarily adding assorted tissue adhesives to ease shaping of the graft, altering the material wrapping the cartilage, or foregoing an encasement altogether [9,[25][26][27][28][29][30] . The manifold existing descriptions in the literature notwithstanding, a systematic approach refining the surgical technique to achieve greater precision and consistency using diced cartilage with fascia has not been previously delineated.
Diced cartilage with fascia represents a potentially ideal graft for dorsal augmentation as it makes use of the lower complication rates associated with autologous grafts, while also providing a graft that has the ability to recreate dorsal aesthetic lines in a natural and predictable manner. The usage of diced cartilage has been variously described in the literature, with consistently satisfactory results reported. Herein, we present our experience, with patients undergoing dorsal augmentation during rhinoplasty, using an updated method of diced cartilage wrapped in fascia.

SURGICAL TECHNIQUE
Proper surgical planning and preparation for dorsal augmentation begins with the consultation and preoperative visit, wherein the nasal anatomy should be thoroughly assessed, and the aesthetic goals of surgery defined, with particular attention directed at the dorsum, established with the patient.
The primary consideration with regards to the pre-operative nasal anatomy is the shape and integrity of the platform created by the confluence of the upper lateral cartilages along the dorsal septum. The presence of significant contour irregularities such as a dorsal hump or inverted-V deformities, indicate the need for proper preparation and modification of the dorsum to support a diced cartilage wrapped in fascia (DCF) graft. Physical exam findings in conjunction with the patient's aesthetic desires dictate the most appropriate source of graft material.
Computer-imaging is also a beneficial communication tool between surgeon and patient as it allows a focused discussion of the patient's anticipated results with the realities and limitations of surgery, as well as the types and degrees of potential changes. This provides the surgeon an opportunity to more accurately gauge the desired shape of the nose and dorsum with regards to nasofrontal angle, radix height, dorsal height, length, and supratip break, which become important considerations in shaping the DCF.
Pre-operatively, the patient is marked in the upright position. The anticipated nasal starting point, dorsal convexity -if present, desired supratip break, and the midline of the face should be marked, as well as the inframammary/infrapectoral crease and xiphoid in the case of costal cartilage harvest.
Cartilage may be harvested from the septum, ears, or rib, depending on the volume requirements of the dorsal augmentation. The physical characteristics of the cartilage sources do vary, with softer cartilage allowing for finer dicing and greater pliability once placed within fascia. Dicing of the cartilage to < 0.5 mm pieces is recommended to minimize the risk of contour irregularities, as shown in Figure 1.
While fascia may be obtained from multiple sources, deep temporalis fascia is the thinnest of commonly used options, and produces minimal donor site morbidity. Once healed, the diced cartilage within the DCF provides the lasting volume, while the fascia simply acts as a temporary vehicle to place and shape the cartilage. For this reason, thinner fascia is preferable for more precise titration of graft size and shape. Care should be taken during fascia harvest to ensure adequate surface area (> 5 cm × 3.5 cm) and that all extraneous fat and muscle is meticulously removed to create the thinnest and most uniform layer of tissue, as shown in Figures 2 and 3.
Once the deep temporalis fascia has been thinned, it is sutured longitudinally into a cylindrical shape with a running-locking 5-0 vicryl to avoid any escape of diced cartilage from the construct. The width of the cylinder is determined by the desired width as well as height of the patient's bridge, generally in a range between 3.2-3.5 cm of fascia diameter. One end of the fascia is then closed and filled with an estimated volume of diced cartilage, then placed along the nasal dorsum.
The DCF will contract and dehydrate when healed, so every effort is made to remove fluid from the DCF prior to making measurements for its final dimensions. The cephalic end of the DCF is placed at the previously marked nasal starting point, and the supratip break marked caudally. The fascia is then closed    A needle is used to create fenestrations throughout the DCF, to allow for free effusion of any remaining fluid within the construct, and to promote quicker fibrous and vascular ingrowth into the graft [ Figure 6]. Corset sutures are placed to taper the graft from a cylindrical shape to a more parabolic shape, consistent with the appearance of the desired dorsal aesthetic lines [ Figure 7]. These corset sutures may be used to great effect to finely calibrate the proportions and dimensions of the graft.
When the final shape has been achieved, the DCF may be placed again along the dorsum of the nose to evaluate the size and shape one final time prior to placement. Deficiency or excess volume and height may be adjusted by making a small incision along the DCF and removing or adding diced cartilage as deemed necessary.
The DCF is secured along its cephalic and caudal ends, and its body shaped by casting. A percutaneous suture is placed through the marked starting point, and secured to the cephalic end of DCF. In cases of excessively wide skin dissection and a resultant large dorsal pocket -such as in removal of a previous implant or graft, multiple percutaneous sutures may be placed to allow for more secure fixation. Along the caudal aspect of the construct, the fascia is secured to the supratip and over the tip complex. The nasal skin envelope may then be re-draped and the shape of the dorsum evaluated.  Casting is the last step and is critical for a successful result. The shape and position of the mid-portion of the graft relies heavily on precise molding and contouring of the cast to shape the coagulum of diced cartilage within the DCF. For this reason, casting with a thermoplastic splint is recommended to allow for precise shaping. Once the ideal shape has been obtained, ice-cold water is poured liberally on the cast to lock in the final shape. The cast and percutaneous sutures are removed 1 week post-operatively. Case examples of primary and revision rhinoplasties using the updated dice cartilage technique are demonstrated in Figures  8-10, respectively. The dorsum will initially be much wider and taller, but the majority of the swelling will resolve in 3-6 months with the final results in 1-2 years.

DISCUSSION
Given the contemporary focus of minimizing complications and creating a life-long result, many rhinoplasty surgeons have shifted towards exclusively using autologous grafts during dorsal augmentation. Diced cartilage fascia techniques have proven attractive for a number of reasons, including their relative pliability, wide availability of materials needed for the construct, and the perceived forgiving nature with regards to contour irregularities.
Diced cartilage fascia techniques for dorsal augmentation in rhinoplasty and revision rhinoplasty have been variously utilized and described for over half a century. Despite producing satisfactory results in many cases, it has received criticism at times for creating a "sausage-like" appearance or an otherwise unnatural look to the dorsum. Also despite its perception as forgiving, it does have a somewhat large inter-surgeon variance with regards to aesthetic outcomes. The term is broadly descriptive, and there remains a wide-range of ways to execute it.
Contour irregularities remain the most common reason for surgeon and patient dissatisfaction after dorsal augmentation using diced cartilage with fascia. Sub-optimal contours may manifest in the form of convexities and concavities, over or under augmentation, deviation, asymmetries, and unnatural dorsal aesthetic lines. Occasionally, natural variations in nasal skin envelope thickness and sebaceous qualities between the dorsum, supratip, tip, infratip and columella, as well as scarring from previous surgeries, may result in a less than ideal appearance to the nasal starting point, radix, dorsum, supratip break, nasal tip, infratip lobule, and columella. Conservative management of minor contour irregularities with nasal exercises (especially within the first month following surgery), and directed injections of kenalog and 5-fluorouracil, will successfully address many of the irregularities observed in the early post-operative period. Persistent contour irregularities beyond post-operative edema involving coalesced diced cartilage will infrequently warrant revision surgery to address.
This updated diced cartilage fascia technique seeks to eliminate variance and enhance precision to create more predictable and consistently beautiful results. Placing greater emphasis on precision and a more algorithmic approach to constructing the DCF graft may result in even improved outcomes for future patients.