A histologic analysis of three-dimensional versus two-dimensional tissue expansion in the porcine model.

OBJECTIVE: Recently, a two-dimensional Silastic Dacron stretching skin device has been developed for scalp reduction surgery. Attached subgaleally, this device stretches skin over time, while avoiding the visible volumetric distention that is typical of three-dimensional tissue expanders. Unlike three-dimensional expanders, the histological changes observed with a two-dimensional stretching device have not been described in the literature. The present study compares the histological effects of two-dimensional and three-dimensional skin tissue expansion in the porcine model. STUDY DESIGN: A university Institutional Review Board-approved study in which 16 domestic piglets were used. The 16 piglets were divided evenly into four cohorts as follows: 1, 1-week control cohort; 2, 1-week experimental cohort; 3, 4-week control cohort; and 4, 4-week experimental cohort. METHODS: Tissue expanders (three-dimensional) and Dacron Silastic tissue stretchers (two-dimensional) were surgically inserted into the lateral skin of 16 domestic pigs. Animals were killed at either 1 or 4 weeks based on group assignment. Light microscopic ocular micrometry and stereological point counting were used to determine the depth of the epidermis, dermis, and subdermal adipose tissue layer; width of the panniculus muscle; diameter of sweat gland follicles; percentage ratio of dermal collagen, blood vessels, and tissue space; and epidermal mitotic index in 100 specimens. One-way ANOVA was used to evaluate statistical differences. RESULTS: Both tissue expanders yielded increased values compared with control subjects, with respect to epidermal, dermal, and fat widths and blood vessel counts, whereas adnexal structures in the panniculus muscle width were unaltered. CONCLUSIONS: Although statistically the two types of expansion produced histologically similar changes, the degree of change varied according to the type of expander that was used and the duration of tissue expansion. Most notably, three-dimensional expansion produced more tissue gain per unit area expanded at both the 1-week and the 4-week time intervals, and early (1-week) two-dimensional tissue expansion stimulated a greater angiogenic response than three-dimensional expansion. These findings will assist the surgeon in understanding the physical changes that occur with these two forms of tissue expansion, as well as the potential clinical advantages and shortcomings of each method.

An evaluation of fibrin tissue adhesive concentration and application thickness on skin graft survival.

OBJECTIVES: To examine the effects of fibrinogen concentration and application thickness of fibrin tissue adhesive on skin graft survival. STUDY DESIGN: Prospective controlled study. METHODS: Ten domestic pigs were included in the study. A 20 x 5-cm area of skin was harvested bilaterally along the flanks of the animals using a Padgett dermatome. The harvested grafts were trimmed into four 4 x 4-cm squares. Donor sites were treated according to group assignment and the non-meshed grafts were placed on the side opposite their initial orientation and secured with staples. Both single- and multiple-donor human fibrin tissue adhesive preparations, with low and high average fibrinogen concentrations of 30 mg/mL and 60 mg/ mL, were used. Adhesive preparations were applied in either a thin layer (0.015 mL/cm2) or a thick layer (0.06 mL/cm2) using a spray applicator. A constant thrombin concentration of 10 U/mL was used in the study. No adhesive was used in the control group and grafts were stabilized with staples. No topical dressings were applied to any of the treatment sites. Animals were sacrificed 4 weeks after graft application. RESULTS: Based on statistical analysis, thickness of adhesive application had a significant effect on skin graft survival. Percent mean graft survival in the control and thin application groups was found to be 92% and 97.8% respectively; the mean survival rate in the thick application group was 63.1%. Fibrinogen concentration, when evaluated independently within the thin and thick application groups, was found to have no significant effect on graft survival. CONCLUSION: Independent of fibrinogen concentration, a thin layer of fibrin tissue adhesive, when applied between two opposing surfaces, does not interfere with and may support the healing process, whereas a thick layer of adhesive inhibits skin graft healing.

Modulation of mechanical properties in multiple-component tissue adhesives.

In vitro, ex vivo, and in vivo studies were performed to investigate the effect of mixing upon the mechanical properties of a two-component tissue adhesive. The hypothesis investigated was that a more complete mixing of the two components would yield an increase in the mechanical performance of the adhesive. This in turn would be demonstrated by improved outcomes in models of clinical sealant application. In vitro stereological analysis of tissue adhesive mixed and delivered by several different applicators demonstrated variation in the amount of mixing provided by each type of delivery system. Ex vivo tensile adhesive strength showed that there was a correlation between the amount of mixing and bonding strength; that is, more thorough mixing demonstrated higher adhesive strength. No significant difference was seen, however, between the different applicator types and impact on in vivo dermal incisional closure strength. There was a correlation, though, in amount of mixing and in vivo hemostasis. In a rabbit spleen incision model, a more thoroughly mixed sealant corresponded with a decrease in time to obtain complete hemostasis, as well as less sealant used. The effects of mixing on tissue-adhesive mechanical performance were influenced somewhat by the amount of mixing provided by the applicator. This effect, however, was dependent upon the sealant formulation and the type of in vivo application.

Mandibular reconstruction using bone morphogenetic protein 2: long-term follow-up in a canine model.

OBJECTIVE: To determine the degree of bone resorption and stability of 3-cm, full-thickness canine mandibular defects reconstructed with recombinant human bone morphogenetic protein 2 (rhBMP-2) and a bioerodible particle carrier followed for 30 months after reconstruction. STUDY DESIGN: Nine dogs, divided into three groups, underwent reconstruction of surgically created 3-cm, full-thickness defects of the body of the mandible. METHODS: Mandibular reconstruction was performed via a combined intraoral and extraoral approach. Using standard plating techniques, a unilateral full-thickness, 3-cm defect was created in the body of the mandible. After stabilizing the defects with titanium reconstruction plates, test implants composed of rhBMP-2 and poly(lactide-co-glycolide) bioerodible particles were placed in the mandibular defects of six animals. Reconstruction plates were removed from test animals at 10 weeks. Three short-term test animals were sacrificed 3 months after reconstruction. Three long-term test animals were sacrificed 30 months after reconstruction to determine the degree of resorption and long-term stability of the rhBMP-2-induced bone. Control implants (carrier without rhBMP-2) were used in three animals and were sacrificed at 3 months. At 9 months, long-term animals were advanced to a solid diet. Masticatory function and body weight were monitored periodically to assess diet tolerance. Roentgenographic photodensitometry was performed on serial dental roentgenograms of the reconstructed segments to determine bone density and the degree of bone resorption over 30 months. After sacrifice, reconstructed segments were harvested and embedded in plastic for histological analysis and histomorphometry to determine the percentage of the defect replaced by mineralized bone (area density) and degree of resorption from 3 to 30 months after reconstruction. The main outcome measures were bone density and bone height determined from serial roentgenograms and percentage of the reconstructed segment replaced by mineralized bone (area density) determined from histomorphometry. RESULTS: Control animals without rhBMP-2 showed no evidence of bone formation across the defect. Histological examination revealed good bone formation in two of three of the short-term test animals with a mean area density of 41.0%. The long-term test animals treated with rhBMP-2 demonstrated good bone formation that was comparable to that of normal host bone by 3 months. The roentgenographic photodensity measurements stabilized at 5 months without evidence of persistent bone resorption. The height of the reconstructed segment (rhBMP-2-induced bone) initially decreased, then stabilized by 11 months after reconstruction with no indication of resorption or failure. Histological examination of the long-term test animals revealed good bone formation across the mandibular defects. However, there were localized areas of thinning of the cortical bone as compared with the short-term test animals sacrificed at 3 months. Histological examination verified the loss of height of the bone in the reconstructed segments. The area density (mean) of the long-term test animals was 56.5%. Despite the decrease in height of the induced bone, there was an increase in area density of the bone over time. CONCLUSIONS: This study demonstrated that rhBMP-2 in a bioerodible particle carrier induced new host bone formation across critical-size mandibular defects. The newly formed bone successfully integrated with existing host bone creating a stable union capable of withstanding the forces of masticatory function in a canine. There was some evidence of early bone resorption (thinning of the cortical bone and decrease in height) in the rhBMP-2-induced bone. The rhBMP-2-induced bone stabilized by 11 months after reconstruction and no further resorption was noted. The percentage of area of the defect replaced by rhBMP-2-induced bone (area density) increased over 30 months. (ABSTRACT TRUNCATED)

Powered instrumentation for rhinoplasty and septoplasty.

Advances in surgical instrumentation are generally intended to allow the performance of a surgical maneuver more efficiently and accurately. Powered instrumentation may allow improved precision and ease in certain aspects of rhinoplasty and septoplasty. Through improved precision, tissue trauma can be minimized.

Grafts amd implants in rhinoplasty and nasal reconstruction.

The quest for nasal symmetry and balance with the face often mandates the need for implantable materials to sculpt and rebuild the nasal skeleton and the overlying tissues. A suitable implant must be biocompatible, strong, and elastic. Implant materials that may be used in the nose can be divided into four groups: autografts, homografts, xenografts, and alloplasts. Each type of implant is reviewed and discussed in the context of rhinoplasty and nasal reconstruction.

Model for evaluating the effect of growth factors on the larynx.

Growth factors are proteins that help regulate the inflammatory response and wound healing in tissues. After laryngotracheal surgery, proper wound healing is important in maintaining the reconstructed airway. The application of growth factor to the respiratory mucosa of the larynx and its effect on wound healing within the airway have not been studied. This study was designed to establish a model for the evaluation of wound healing after the application of growth factor to composite respiratory mucosa and cartilage surfaces at the time of laryngotracheoplasty. Forty rabbits underwent anterior cricoid cartilage split with or without the use of a cartilage graft. Platelet-derived growth factor or a placebo substance was applied to the wound at the time of surgery. This study offers a model for studying wound healing in the airway that is reproducible with limited morbidity.

The effects of resorbable plates on rabbit ear cartilage.

BACKGROUND: When performing septorhinoplasty, deviated segments of septal cartilage can be straightened using cartilage or bone as splinting grafts. In some cases, autologous material is not available without an additional surgical procedure to harvest cartilage or bone. It is possible that resorbable plates can be used to splint and straighten deviated cartilage. Experience using bioresorbable rigid fixation devices on cartilage has been limited. OBJECTIVE: To examine early histopathologic changes of rabbit ear cartilage and adjacent soft tissue following implantation with bioresorbable plates. DESIGN: Nonrandomized, placebo-controlled trial. SUBJECTS: Twelve adult New Zealand white rabbits. MATERIALS AND METHODS: Ten adult New Zealand white rabbits (20 ears) underwent stenting of intact ear cartilage with LactoSorb plates (Lorenz, Jacksonville, Fla). Rabbits were killed 28 days after implantation, and the soft tissue, plates, and cartilage were harvested and prepared for histological examination. As controls, 2 rabbits (4 ears) underwent dissection and closure without stenting. RESULTS: Six rabbits experienced superficial skin breakdown on the ventral surface of the ear caused by excessive wound tension of the implant. The cartilage-plate interface and the surrounding soft tissues stenting the dorsal side of the ear remained free of inflammation or necrosis for all animals. Simple elevation of the perichondrium revealed no differences in the appearance of the cartilage between the control and test rabbits. CONCLUSIONS: Resorbable plates have no deleterious effects on cartilage during the first month of implantation. While short-term studies have documented the safety and efficacy of using bioresorbable plates, further studies are recommended.

Use of octyl-2-cyanoacrylate for skin closure in facial plastic surgery.

Octyl-2-cyanoacrylate is a long carbon chain cyanoacrylate derivative that is stronger and more pliable than its shorter chain derivatives. One hundred and eleven patients underwent elective surgical procedures by the same surgeon using either octyl-2-cyanoacrylate or sutures for skin closure at the University of Illinois at Chicago. Most patients underwent excision of benign skin lesions with a mean wound size of 112 mm3. Patients were randomized into either control (vertical mattress suture closure) or test groups (closure with octyl-2-cyanoacrylate). Surgical judgment was used to determine which wounds in each group required application of subcutaneous sutures to relieve tension and aid in skin edge eversion. Generally, full-thickness (through dermis) wounds larger than 1 cm3 required the use of subcutaneous sutures. The time required to close the epidermis with suture (mean, 3 minutes and 47 seconds) was about four times that of octyl-2-cyanoacrylate (mean, 55 seconds). Wounds were evaluated at 5 to 7 days for infection, wound dehiscence, or tissue reaction, and at 90 days using the modified Hollander wound evaluation scale. At 1 year, photographs of the wounds were evaluated by two facial plastic surgeons that graded the cosmetic outcome using a previously validated visual analog scale. There were no instances of wound dehiscence, hematoma, or infection in either group. Results of wound evaluation at 90 days determined by the modified Hollander scal revealed equivalent cosmetic results in both groups. Results of the visual analog scale ratings showed scores of 21.7 +/- 16.3 for the 49 patients treated with octyl-2-cyanoacrylate and 29.2 +/- 17.7 for the 51 control patients treated with sutures. The lower visual analog scale score represented a superior cosmetic outcome at 1 year with the octyl-2-cyanoacrylate as compared with sutures. This difference is statistically significant at p = 0.03. Additionally, patient satisfaction was very high in the group treated with octyl-2-cyanoacrylate.

The effect of recombinant human bone morphogenetic protein-2 on the integration of porous hydroxyapatite implants with bone.

To determine if recombinant human bone morphogenetic protein-2 (rhBMP-2) can be adsorbed onto porous ceramic hydroxyapatite (HA) and promote the integration of HA to host bone, 54 subperiosteal pockets were created on the skulls of 19 adult Pasteurella-free white rabbits. Fourteen HA implants were saturated with saline and placed in subperiosteal pockets (control), 22 HA implants were saturated with saline and placed into subperiosteal pockets after burring 1-2 mm of calvarium to expose bleeding cancellous bone, and 18 HA implants were saturated with rhBMP-2 and placed into subperiosteal pockets. The animals were sacrificed at 1 month with examination to determine implant mobility. Histology was used to determine the amount of bone growth into the implant. Of the 14 control sites, 10 implants were found to be freely mobile, five demonstrated host bone resorption, and only one exhibited bone growth into the implant. Of the 22 burred sites, eight were freely mobile and 10 demonstrated bone growth into the implant (p = 0.04). Of the 18 rhBMP-2 sites, only two were freely mobile, none demonstrated host bone resorption, and 16 exhibited bone growth into the implant (p = 0.00002). This study supports the use of porous ceramic HA as a biocompatible, osteoconductive implant material for use in craniomaxillofacial augmentation and reconstruction. It also provides evidence that rhBMP-2 enhances osseointegration, thereby fixing the implant in position against the host-bone interface. In the clinical setting, osseous fixation of the implant should aid in preventing displacement, minimizing host bone resorption, and decreasing the incidence of extrusion.

Interstitial Nd:YAG photocoagulation for vascular malformations and hemangiomas in childhood.

BACKGROUND: Vascular malformations and cavernous hemangiomas are common in childhood. Although cavernous hemangiomas may resolve spontaneously, aggressive intervention is required when their growth could damage vital adjacent structures, such as the orbit, nose, or tongue. OBJECTIVE: To evaluate the efficacy of interstitial Nd:YAG photocoagulation as an adjunct to intralesional and systemic corticosteroids for treatment of hemangiomas and vascular malformations that had failed to respond to other therapies. DESIGN: Prospective, nonrandomized trial. SETTING: Two referral practices of facial plastic and reconstructive surgery in tertiary care, academic medical centers. PATIENTS: Ten consecutive pediatric patients with either hemangioma or vascular malformation of the head and neck. INTERVENTION: Laser photocoagulation with an interstitial technique. The Nd:YAG fiber was introduced into the lesion via a 14-gauge angiocatheter needle, and the laser fiber was advanced as coagulation proceeded within the tissue. MAIN OUTCOME MEASURES: Decrease in the area of the target lesion, amount of energy applied, and number of treatments required to achieve reduction in size. RESULTS: Long-term follow-up demonstrated regression of the lesion in all 10 patients with good cosmetic results. The range of reduction in size was 20% to 98%. No reexpansion of the lesions was noted after a mean follow-up of 13 months. CONCLUSIONS: Interstitial photocoagulation of hemangiomas and vascular malformations is an effective treatment for carefully selected patients. When properly applied, this technique can achieve reduction in the size of these lesions without compromising cosmesis.

Peripheral nerve regeneration: comparison of laminin and acidic fibroblast growth factor.

PURPOSE: In an effort to show the differences between neurotrophic factors, laminin and acidic fibroblast growth factor (aFGF) were compared in terms of their abilities to regenerate axons in vivo over an extended distance. MATERIALS AND METHODS: The sciatic nerve was transected in 15 Sprague-Dawley rats. A 15-mm Silastic tube (Dow Corning, Midland, MI) was placed between the ends of the cut nerve and filled with either laminin, aFGF, or buffer applied to collagen sponges. RESULTS: Ten weeks postimplantation, mean axon counts showed that both laminin (2432) and aFGF (1612) produced significantly higher numbers of axons than controls (1009) (P < .05) and that laminin showed significantly more nerve regeneration than aFGF (P < .05). CONCLUSION: These results indicate that laminin and aFGF enhance peripheral nerve regeneration across a large gap, presumably through their neurotrophic effects and mitogenic properties on supporting cells. Furthermore, it is concluded that the transient nature of aFGF's effect on the regenerative environment limits its effectiveness at regenerating axons over a prolonged period of time.

The effect of platelet-derived growth factor on tracheal wound healing.

In order to evaluate a new method for the direct application of a polypeptide growth factor to injured tracheal epithelium and to determine the effect of topical platelet-derived growth factor (PDGF) on tracheal wound healing, a controlled animal study was designed using six adult beagle dogs. Four 2x1 cm mucosal defects were created in the tracheal lumen of each dog for a total of 24 experimental sites. Twelve wounds were treated with PDGF in a collagen-fibrin composite tissue adhesive (CTA) carrier. Eight sites received CTA alone and four were left untreated. Healing was assessed by endoscopic exam on post-operative days 4, 7, 10, 14, 17 and 21. The animals were sacrificed on day 21 and the tracheas were harvested for histological examination of the experimental sites and adjacent unwounded trachea. By 21 days, complete healing of all sites was observed endoscopically. Wounds treated with CTA or PDGF-CTA healed at a faster rate than control sites. The PDGF-CTA treated wounds demonstrated excessive granulation tissue formation. Histological examination demonstrated a higher percentage of wound coverage with ciliated epithelium most similar to normal trachea in the PDGF treated wounds. CTA is effective as a carrier for the direct delivery of a growth factor to injured tracheal epithelium. The application of CTA or PDGF-CTA results in a more rapid rate of tracheal wound healing as compared with control wounds. PDGF-CTA led to increased acute local inflammatory changes but was associated with a structurally more normal respiratory epithelium after healing. Physiological studies are necessary to determine the functional significance of these findings.

Fibrin tissue adhesive in otolaryngology-head and neck surgery.

In otolaryngology-head and neck surgery, fibrin tissue adhesive (FTA) is primarily used for fixation of tissues, for attaining hemostasis, or for drug delivery. It can be used for positioning implants or ossicles in the middle ear or as a sealant in closure of cerebrospinal fluid leaks. FTA is an excellent hemostatic agent and can be used for controlling capillary bleeding along the cut surface of muscle or in a previously operated site. As a delivery system, FTA can be used to administer antibiotics, chemotherapeutic agents, or growth factors. New technology is providing safer homologous products, stronger autologous products with higher fibrinogen levels, and better applicators.

Use of alar batten grafts for correction of nasal valve collapse.

OBJECTIVE: To determine the efficacy of alar batten grafts for the correction of internal and external nasal valve collapse. DESIGN: In this retrospective study, a questionnaire was used to ask patients to rate their nasal breathing before and after application of alar batten grafts. SETTING: Private practice and academic tertiary referral medical center. PATIENTS: The questionnaire was given to 63 patients who underwent application of alar batten grafts between 1980 and 1995. Forty-six patients (73%) responded and were included in the study. INTERVENTION: Alar batten grafts were applied into a precise pocket via a limited endonasal incision or via the external rhinoplasty approach. The grafts consisted of curved septal cartilage or auricular cartilage and were applied to the site of maximal lateral nasal wall collapse. The convex surface of the cartilage was oriented laterally to allow maximal lateralization of the collapsed portion of the lateral nasal wall. In most cases, alar batten grafts were applied caudal to the existing lateral crura and extended from the lateral one third of the lateral crura to the piriform aperture. OUTCOME MEASURES: The degree of nasal airway obstruction was determined by subjective scoring on a scale from 1 (no obstruction) to 5 (complete obstruction) before and after surgery. The patency of the internal airway was also assessed on physical examination. RESULTS: The results of the study revealed that all but 1 of the 46 patients experienced an improvement in their nasal airway obstruction. The mean improvement in nasal airway obstruction was 2.5 on a scale of 5. Patients that had the least improvement had intranasal scarring in the region of the internal nasal valve, loss of vestibular skin, or excessive narrowing at the piriform aperture. Physical examination revealed a significant increase in the size of the aperture at the internal or external nasal valve after the application of the alar batten grafts. There was minimal postoperative fullness in the supraalar region, where the alar batten grafts were applied. With time, this fullness decreased, leaving little evidence of the graft and an overall improvement in the aesthetic result. CONCLUSIONS: Alar batten grafts are effective for long-term correction of internal and external nasal valve collapse that is not complicated by intranasal scarring in the region of the nasal valve, loss of vestibular skin, or excessive narrowing at the piriform aperture.

Powered instrumentation for dorsal reduction.

We describe the use of powered instrumentation for precise modification of the bony nasal dorsum. Specific modifications were made to design a drill specifically for the bony nasal dorsum. This drill has a protective sheath that covers all but the active part of the drill, protecting the skin-soft tissue envelope, and it also has suction at the resection site. In some cases an osteotome is used to reduce the hump and the drill is used to achieve additional reduction and to smooth the exposed edges under direct vision. In other cases the entire bony hump is reduced using the drill. The nasal dorsum drill offers a precise alternative to the rasp. The precision of the drill is highlighted in cases in which limited reduction is needed, as in cases of a single or several spicules requiring reduction and smoothing after osteotomy, or a single 4 mm raised area requiring limited reduction. The design of rasps makes it difficult to work on these focal areas without unnecessarily rasping surrounding areas, whereas the drill may be used to reduce the entire hump, to smooth the edges after osteotomy, or in a more precise and limited fashion when indicated. The drill may be less traumatic to the skin-soft tissue envelope because it does not rely on the potentially bruising back and forth motion typical of rasping. The nasal dorsum drill may decrease the incidence of bony dorsal irregularities after rhinoplasty.

Fibroblast growth factor-induced motor end plate regeneration in atrophic muscle.

OBJECTIVE: To determine whether fibroblast growth factor 1 implanted with viable nerve into atrophic muscle will stimulate formation of functional, acetylcholine producing motor end plates. DESIGN: Twelve male Lewis rats underwent predenervation of the hamstring muscle 8 weeks before implantation of the nerve at a site distant from the original motor end plate. Six animals underwent implantation of the tagged nerve ending into atrophic muscle with 50 microgram of fibroblast growth factor 1 in a fibrin adhesive carrier (group 1). Three animals underwent implantation with nerve, fibrin adhesive, and no fibroblast growth factor 1 (group 2); and three animals underwent implantation with fibroblast growth factor 1 and fibrin adhesive with no nerve (group 3). Animals were killed 9 weeks after implantation and nerve and muscle specimens were harvested. MAIN OUTCOME MEASURES: Histoenzymologic methods for acetylcholinesterase and silver impregnation of nerve fibers were performed 9 weeks after fibroblast growth factor 1-fibrin adhesive implantation. Variables included the number of motor end plates per highpower field and motor end plate length. RESULTS: Robust axonal sprouting and formation of multiple motor end plates were found arborized in serial fashion equidistant around the implanted nerve ending. Rare extrasynaptic staining occurred. End plate lengths were significantly shorter in the fibroblast growth factor 1-treated muscles (group 1) than in the specimens without fibroblast growth factor 1 (group 2) (31.2 vs 58.5 micron; P>001, paired t test). The arborization of motor end plates, rare extrasynaptic staining, and shorter end plate lengths seen in group 1 were all consistent with mature motor end plates. Controls (group 3) displayed limited motor end plate formation and extensive extrasynaptic staining typical of denervation. CONCLUSION: This study presents encouraging evidence that fibroblast growth factor 1 with fibrin adhesive carrier can facilitate the reinnervation of atrophied muscle by enhancing the formation or revitalization of motor end plates. Future studies will address muscle function and use of different carrier materials.

Vascular anatomy of the nose and the external rhinoplasty approach.

OBJECTIVE: To characterize the venous, lymphatic, and arterial blood supply of the nose and determine the effect of the external rhinoplasty approach on this vasculature. We hypothesized that dissection in the areolar tissue plane below the musculoaponeurotic layer of the nose will preserve the nasal vasculature and minimize postoperative nasal tip edema. DESIGN: The study included preoperative and postoperative clinical evaluation, cadaver dissection, and histologic examination. In the clinical section, lymphoscintigraphy was performed before and after rhinoplasty using the endonasal (transnostril) or external (open) approach. Additionally, nasal tip edema was subjectively quantified at specified interval after surgery. In the cadaver dissection section, 15 fresh cadavers were dissected to identify the venous and arterial vasculature. In the histology section, fresh nasal tissue was examined by light microscopy to verify the anatomy of arteries, veins, and lymphatic vessels. SETTING: Subjects for the clinical section of the study were volunteers undergoing primary rhinoplasty surgery at the University of Illinois College of Medicine at Chicago. PATIENTS: Lymphoscintigraphy was performed on nine patients who underwent rhinoplasty surgery. Seven of these patients underwent postoperative lymphoscintigraphy. INTERVENTIONS: The rhinoplasty procedures included three different methods of exposure of the nasal structures. Two patients underwent an endonasal (transnostril) nondelivery approach using a transcartilaginous incision. Five patients underwent the external approach with three receiving dissection in the areolar tissue plane below the musculoaponeurotic layer (preserving major nasal vasculature) and two undergoing dissection above the musculoaponeurotic layer (disrupting nasal vasculature). MAIN OUTCOME MEASURES: In the clinical section of the study, the outcome measures were tracer flow as seen on lymphoscintigraphy and tip edema scores subjectively quantitated on a scale from 1 (none) to 4 (maximal). RESULTS: Clinical Section: Lymphoscintigraphy revealed flow of tracer along the lateral aspect of the nose (cephalic to lateral crura) to the preparotid lymph nodes. Postoperative scans revealed preservation of flow of tracer with the endonasal (transnostril) approach and the external approach with submusculoaponeurotic areolar tissue plane dissection. There was loss of normal flow of tracer with the external approach using dissection that disrupted the musculoaponeurotic layer with supratip debulking. The nasal tip edema scores for the transnostril and external approach using areolar plane dissection were significantly lower than the external approach with disruption of the musculoaponeurotic layer. Cadaver Dissection Section: Other than the lateral nasal veins, the major arteries, veins, and lymphatic vessels ran superficial to the musculoaponeurotic layer of the nose. The lateral and dorsal nasal and the columellar arteries comprise an alar arcade that provides the major blood supply to the flap elevated in the external rhinoplasty approach. Histologic Section: Light microscopy of plastic resin sections verified the lymphoscintigraphic and cadaver dissection findings. The lymphatic vessels were located primarily in the reticular dermis above the muscle layer. CONCLUSIONS: The major arterial, venous, and lymphatic vasculature courses in or above the musculoaponeurotic layer of the nose. In the external rhinoplasty approach, dissection in the areolar tissue plane below the musculoaponeurotic layer will minimize tip edema and protect against skin necrosis by preserving the major vascular supply to the nasal tip.