Учебники / Rhinoplasty Dissection Manual Toriumi 1999
.pdfBy using a two-prong retractor, evert the caudal margin of the nostril in which an inter cartilaginous incision was made and, by applying pressure with the middle finger of the nondominant hand, define the caudal margin of the lower lateral cartilage. Pressing cepha lad on the nasal dome will cause the caudal margin to appear laterally. Remember that the non-hair-bearing area is a guide to the caudal margin of the lateral crus. Furthermore, pal pation of the cartilage edge with the handle of the scalpel can be helpful before cutting. By using the two-prong retractor to obtain proper exposure, make the marginal incision just caudal to the caudal edge of the lower lateral cartilage (Fig. 5). Great care must be taken as the lateral incision nears the midline. Make sure that the incision follows the cartilage edge and does not take a "short-cut" along the alar rim, which can damage the facet area. Great care must be taken not to cut across a narrow dome or intermediate crus (1,2).
Delivery of lower lateral cartilages
At this stage, an intercartilaginous incision and marginal incision on one side and a transcartilaginous incision on the other side have been made. Reinsert the two-prong re tractor into the nostril with the intercartilaginous and marginal incisions and present the caudal margin of the lower lateral cartilage with the aid of pressure from the third finger of the nondominant hand.
Use a slightly curved, fine-pointed dissecting scissors to lift and dissect the soft tissues from the surface of the lower lateral cartilage (Fig. 6). Perform this dissection by inserting scissors into the marginal incision laterally and then separate the perichondrium of the lower lateral from the overlying external skin and soft tissue with a spreading motion. If this is difficult, caudal traction on the vestibular skin underlying the lower lateral cartilage, with a fine two-prong hook, will facilitate this maneuver (Fig. 7) by pulling the lateral crus into the vestibule and thus opening up the potential dissecting plane. Avoid damaging the overlying muscle and nasal vasculature (1,2).
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Figure 5. Marginal incision. The nondominant hand is critical to obtain proper exposure.
Figure 6. Dissect the soft tissues from the superficial surface of the lower lateral car
Do not work too far laterally. The latera l one fourth of the lower lateral cartilage be avo ided by the surgeon in near ly all cases.
Place the hook end of a Nievert retracto r through the inter carti laginou s incision an the now-free later al cr us down , like a visor. until it appears outside of the vestibule. be held in this position by the Nievert or by another suitable instrument (Fig . 8).
Examine the lower latera l cartil ages for unique anatomic feat ures and asymmetrie
Figure 7. Caudal traction on the vestibular skin underlying the lower lateral cartilage fine two-prong hook pulls the lateral crus into the vestibule and opens the potential di ing plane.
Figure 8. Delivery of lateral crus of lower lateral cartilage.
THE EXTERNAL (OPEN) RHINOPLASTY APPROACH
Background
The external rhinoplasty approach to the nose provides ma ximal exposure of the lower lateral cartilages, upper lateral cartilages (Ul.Cs) , middl e nasal vault, and bon y nasal vault. These supportive structures can be manipulated in a precise and sym metric fashion . The in creased exp osure facilitates accurate suture placement and fixation of cartilage grafts. The external rhinoplasty approach also facilitates diagnostic capability and is a tremendous aid in teaching rhinoplasty (3-10) (Appendix K).
The incisions used in this app roach include a transcolumellar incision connected to bi lateral marginal incisions. The actu al configuration of the tran scolumellar inci sion is not as critical as the placement of the inci sion . The incision should be made at the level of the mid columella where the caudal margins of the medial crura lie close to the skin and can sup port the incision to help prevent a depressed scar. An inverted-V incision , or some other broken -line incision, is used to break up the scar and lengthen it to minimize scar contrac ture. The surgical dissection must be performed in the proper areolar tissue planes to min imize tissue damage and scarring, maintain hemostasis, and maximize redraping of the skin/soft-tissue envelope. Dissection in proper tissue planes will help preserve vascular structures of the flap , ensure flap viability, and minimize bleeding, postoperative edema, and scarring ( I I) .
NASAL DISSECTION: EXTERNAL (OPEN) RHINOPLASTY APPROACH
Marking the Transcolumellar Incision
Begin the dissection by outlining the transcolumellar incision used in the external rhino plasty approach with a marking pen . Mark an inverted-V transcolumellar inci sion at the level of the midcolumella (Fig. 9). The midcolumellar incision should be marked midway between the top of the nostril and the base of the columella, where the caudal margin of the medial crura lie just beneath the skin, to provide support for the incision. The midcolumel lar incision will be connected to bilateral marginal inci sion s, which are placed ju st caudal to the caud al margin of the lateral crura (Fig . 10). The marginal incision should not be made along the rim of the nostril (rim inci sion). The marginal incision may be marked with a marking pen as well.
Beginning laterally, make a light incision throug h vestibu lar skin 1 to 2 mm cauda l to the caudal margin of the late ral crura . Follow the caudal margin of the lateral crura as the inci sion is extended medi ally . (The dissector has already mad e the marginal incision on one side; here simpl y make a marginal incision on the other side .)
Define the Columellar Flap
By using angled Con verse scissors, or another suitable dissecti ng scisso rs, elevate the thin vestib ular skin of the flap that covers the medial crura. Insert the scissors beneath the col umellar extension of the marg inal incision and dissect med ially in the correct plane of dis section, below the musculoaponeurotic layer (Fig. 13). The scissors should then pass super ficia l to the caudal margin of the ipsilateral and then contralateral medial crus (Fig . 14). Guide the scissors through the oppos ing colume llar extension of the marg inal incision (Fig . 15). During this dissection, take special care to avoid dama ging the flap or the caud al margin of the medial crura . Use the scissors to spread the tissues in the plane of dissection (Fig. 16). If not positioned properly, the dissector may cut through the cauda l margin of the media l crura. To avoid this, the dissector must remain caudal to the medial crura and dissects very carefully.
Flap Elevation
Use the Con verse scissors to compl ete the midcolumellar incis ion without beve ling the incisio n or damaging the medial crura (Fig. 17). Take specia l care to avoi d beveling this in cisio n. Use a narrow do uble-prong hook to retract the flap. Th e paired columellar arte ries may be see n, and typic ally must be cauterized with bipolar cautery .
Figure 13. To elevate the thin vestibular skin of the flap that covers the medial crura, insert the scissors beneath the columellar extension of the marginal incision and dissect medially in the correct plane of dissection , below the musculoaponeurotic layer. If one meets resis tance, they can alternate dissection to the contralateral side of the columella.
