Kun Hwang

Impact of nicotine on bone healing.

A limited number of experimental animal studies and in vitro data confirm that nicotine impairs bone healing, diminishes osteoblast function, causes autogenous bone graft morbidity, and decreases graft biomechanical properties. Therefore, our long-term goal is to develop an effective therapy to reverse the adverse impact of nicotine from tobacco products. However, before accomplishing this goal, we had to develop an animal model. Our hypotheses were nicotine administration preceding and following autogenous bone grafting adversely affected autograft incorporation and depressed donor site healing in a characterized animal wound model. Hypothesis testing was accomplished in bilateral, 4-mm diameter parietal bone defects prepared in 60 Long-Evans rats (male, 35-day-old). A 4-mm diameter disk of donor bone was removed from the left parietal bone and placed in the contralateral defect. The donor site served as a spontaneously healing bone wound. The rats were partitioned equally among three doses of nicotine administered orally in the drinking water (12.5, 25, and 50 mg/L). For each dose, the duration and sequence of nicotine treatment followed four courses, including no nicotine and designated combinations of nicotine administration and abatement prior to and following osseous surgery. Experimental sites were recovered on 14 and 28 days postsurgery, responses quantitated, and data analyzed by analysis of variance and post hoc statistics (p < or = 0.05). We developed a convenient and effective osseous model, and the results validated our hypothesis that nicotine negatively impacts on bone healing.

Analysis of orbital bone fractures: a 12-year study of 391 patients.

This retrospective study evaluates 391 patients with orbital bone fractures from a variety of accidents that were treated at the department of Plastic and Reconstructive Surgery, Inha University Hospital, Incheon, South Korea, between February 1996 and April 2008. The medical records of these patients were reviewed and analyzed to determine the clinical characteristics and treatment of the orbital bone fractures.The following results were obtained. The mean age of the patients was 31.1 years, and the age range was 4 to 78 years. The most common age group was the third decade of life (32.5%). There was a significant male predominance in all age groups, with a ratio of 4.43:1. The most common etiology was violent (assault) or nonviolent traumatic injury (57.5%) followed by traffic accidents (15.6%) and sports injuries (10.7%).The most common isolated orbital bone fracture site was the orbital floor (26.9%). The largest group of complex fractures included the inferior region of the orbital floor and zygomaticomaxilla (18.9%). Open reduction was performed in 63.2% of the cases, and the most common fracture reconstruction material was MEDPOR (56.4%) followed by a resorbable sheet (41.1%). The postoperative complication rate was 17.9%, and there were no statistically significant differences among the reconstruction materials with regard to complications. During follow-up, diplopia, hypoesthesia, and enophthalmos occurred as complications; however, there was no significant difference between porous polyethylene sheet (MEDPOR) and resorbable sheet groups.Long-term epidemiological data regarding the natural history of orbital bone fractures are important for the evaluation of existing preventative measures and for the development of new methods of injury prevention and treatment.

Analysis of Nasal Bone Fractures; A Six-year Study of 503 Patients

The aim of this study is to classify the nasal bone fractures based on computed tomography (CT) analysis and patterns of the nasal bone fractures, and review 503 cases treated between 1998-2004 at the Department of Plastic Surgery, Inha University Hospital, Incheon, South Korea. The age, sex, etiology, associated injuries, pattern of fractures and treatments were reviewed and a radiographic study was analyzed. Plain simple radiographs of lateral and Waters view of the nasal bones combined with computed tomography scans were done. Nasal bone fractures were classified into six types: Type I) Simple without displacement; Type II) Simple with displacement/without telescoping; IIA; Unilateral; IIAs) Unilateral with septal fracture; IIB) Bilateral; IIBs) Bilateral with septal fracture; Type III) Comminuted with telescoping or depression. Diagnosis of nasal bone fractures were made positively by plain x-ray films in 82% of cases, negative finding was 9.5% and 8.5% of cases were suspicious of the fractures. Reliability of the plain film radiographs of the nasal bone fracture was 82% in this study. In the most of the fractured nasal bones (93%) the closed reduction was done, open reduction in 4% and no surgical intervention in 3%. Nasal reduction was carried out in average 6.5 days post the injury. The patterns of the nasal bones fractures classified by CT findings were type IIA (182 cases, 36%), IIBs (105 cases, 21%), IIB (90 cases, 18%), IIAs (66 cases, 13%), I (39 cases, 8%) and III (21 cases, 4.3%). We think the CT is necessary for diagnosing nasal bone fracture because the reliability of the plain film was only 82%.

Surgical anatomy of the orbit of Korean adults.

When operating in and around the orbit, the key to a successful result is precise anatomical localization. However, there is no precise study about the localization of vital orbital structures from reliable periorbital bony anatomy of the Korean adult. This study was constructed to give pertinent anatomical measurements to which the plastic and maxillofacial surgeon may refer. The 82 orbits obtained from 41 skulls of adult Koreans were measured with Vernier calipers and Marshac calipers. Superiorly, the supraorbital fissure was 40.0 +/- 2.5 mm from the supraorbital notch. Medially, the posterior ethmoidal foramen was 31.7 +/- 3.0 mm from the anterior lacrimal crest. Inferiorly, the infraorbital fissure where the infraorbital groove started was 26.4 +/- 2.6 mm from the infraorbital foramen. Laterally, the supraorbital fissure was 34.3 +/- 2.7 mm from the frontozygomatic suture. These distances are suggested as appropriate safe distances from each periorbital bony landmark. Dissection beyond that distance should be done with great caution.

Analysis of facial bone fractures: An 11-year study of 2,094 patients

Purpose: The medical records of these patients were reviewed and analysed to determine the clinical characteristics and treatment of facial bone fractures. Patients and Methods: This is a retrospective study of 2,094 patients with facial bone fractures from various accidents that were treated at the Inha University Hospital from 1996 to 2007. Results: The most common age group was the third decade of life (29%). Males were more common than females (3.98:1). The most common aetiology was violent assault or nonviolent traumatic injury (49.4%). The most common isolated fracture site was the nasal bone (37.7%), followed by the mandible (30%), orbital bones (7.6%), zygoma (5.7%), maxilla (1.3%) and the frontal bone (0.3%). The largest group with complex fractures included the inferior region of the orbital floor and zygomaticomaxilla (14%). Closed reduction was performed in 46.3% of the cases while 39.7% of the cases required open reduction. For open reductions, the most commonly used soft-tissue approach was the intraoral approach (32.3%). The complication rate was 6.4% and the most common complication was hypoesthesia (68.4%) followed by diplopia (25.6%). Conclusion: Long-term collection of epidemiological data regarding facial fractures and concomitant injuries is important for the evaluation of existing preventive measures and useful in the development of new methods of injury prevention and treatment.

correction of Sunken and/or Multiply Folded Upper Eyelid by Fascia-fat Graft

&NA; Sunken and/or multiply folded upper eyelid is one of the common, troublesome complications that can occur after Oriental blepharoplasty. In addition to orbital volume depletion, the traumatic surgical procedure of excessive fat removal might result in a varying degree of adhesion and injury to the orbital septum. Adhesiotomy followed by a restoration of volume is generally believed to be the logical way to correct such deformity. To restore volume and prevent re‐adhesion, local tissues of the upper eyelid, free‐fat graft, and dermis‐fat graft have been used. However, local tissues are usually insufficient because of previous surgery, and the survival rate of grafted fat is often unpredictable. Moreover, the heaviness of the dermis‐fat composite makes it a less than satisfactory choice. The authors value the use of free fascia‐fat composite grafts for the treatment of such disfigurements. The fasciafat composite is expected to have a better survival rate than free fat alone and to be lighter than a dermis‐fat composite. In addition, the fascia‐fat composite is abundant throughout the body and provides anatomical structure more similar to that of the repair site, namely, the damaged orbital septum and fat. The authors prefer the mons pubis, preauricular, and temporal areas for the donor site depending on the status of the damage. They treated 13 patients with sunken and/or multiply folded upper eyelids by fascia‐fat composite grafts and obtained satisfactory results. (Plast. Reconstr. Surg. 107: 15, 2001.)

Location and nature of retro-orbicularis oculus fat and suborbicularis oculi fat.

The aim of this study is to elucidate the anatomic location and histologic nature of the retro-orbicularis oculus fat (ROOF) and suborbicularis oculi fat (SOOF) around the orbital area. Seventeen hemifaces of 12 Korean adult cadavers were used. ROOF and SOOF were observed in all specimens. ROOF was located in a supraorbital area within a range of between a medial +41 and a lateral −39 degrees to a vertical midpupillary line. The shape is crescent and almost symmetric when folded in half. The horizontal length of ROOF was approximately two thirds of a transverse orbital dimension. The height was approximately one third of a vertical orbital dimension. SOOF was located in the inferolateral side of the orbit within a range between a medial +15 and a lateral −89 degrees to a vertical midpupillary line. The SOOF looks like a hockey stick head. The SOOF is divided into two parts, horizontal and vertical. The length of the SOOF horizontal part is almost equal to a transverse orbital dimension (a). The height of the SOOF vertical part was approximately three fourths (b × 3/4) of the vertical orbital dimension (b), and the width of vertical part was one fourth (a/4) of a transverse orbital dimension (a). Most of the SOOF vertical part was outside the lateral orbital rim, and the horizontal part was below the infraorbital rim. Histologically, ROOF and SOOF were situated deep to the orbicularis oculi muscle and superficial to the orbital septum and periosteum. ROOF and SOOF consisted more of fibrofatty tissue than the pure fatty nature of orbital fat. The findings in this study might be conducive to the practice of blepharoplasty and midface lift.

Anatomy of pectoral fascia in relation to subfascial mammary augmentation

The aim of this study is to elucidate the anatomic details of the pectoral fascia in relation to subfascial breast augmentation. Thirty-two breasts of Korean cadavers were dissected and studied grossly and microscopically. The superficial pectoral fascia (SPF) was easily undermined and separated with an Agris-Dingman dissector. A gentle pushing force by the dissector could stretch the SPF and extend the subfascial pocket further at the lateral border of pectoralis major muscle (PM). The dissector head stayed inside the pocket, not perforating through the fascia. Near the inferior border of PM at the level of the sixth intercostal space, the dissection was hard to advance down beyond rectus abdominis muscle (RA). Yet a continuous vigorous dissection led into the subcutaneous layer of the abdominal wall over RA. The SPF is thick and continues to superficial axillary fascia at the lateral end of the muscle. At the inferior border of the PM (sixth intercostal space), however, the pectoral fascia became thin and feeble. The subfascial implants should be placed under the SPF, laterally beyond the lateral border of PM and inferiorly under the glandular tissue of the breast below the sixth intercostal space.

Pseudomelanoma after laser therapy.

An 18-year-old man had a melanocytic nevus on the chin that had been treated with three different lasers at a private clinic for 2.5 years. This lesion was excised and sent to a pathologist. The initial histological diagnosis was reported as compound nevus coexistent with changes suspicious of malignant melanoma. The reevaluation of histology together with the clinical information that the lesion had been pretreated with laser resulted in a revised diagnosis of pseudomelanoma. It is important to be aware of this benign pseudomelanoma, which can arise as a complication of laser therapy, to avoid subjecting patients to unnecessary surgical procedures or other forms of adjuvant treatment.

Innervation of the lower eyelid in relation to blepharoplasty and midface lift: clinical observation and cadaveric study.

Ectropion or scleral show resulting from weakness of the lower eyelids is not uncommon after lower blepharoplasty or midface lift via blepharoplasty incision. Denervation of the pretarsal orbicularis oculi muscle (OOM) attributes to such complications. The authors analyzed 102 patients who underwent midface lift via lower blepharoplasty incision for the past 3 years and investigated the motor nerve innervation of the lower OOM in 20 cadavers. They encountered two cases of ectropion attributed to the denervation of the pretarsal OOM: one with dry-eye syndrome and scleral show, and the other with a “polar bear-like appearance” (i.e., outer eversion of the lower eyelid). All pretarsal and preseptal OOMs were innervated by five to seven terminal twigs of the zygomatic branches of the facial nerve that approached the muscle at a right angle. The medial portion of the lower OOM was innervated by one to two terminal twigs of the buccal branch, and the middle portion was innervated with two to three twigs of the zygomatic branch. The lateral portion was supplied by the uppermost zygomatic branch, which split into two to four twigs. The mean horizontal distance between the lateral canthus and the zygomatic branch was 2.31 ± 0.29 cm (range, 1.7–2.7 cm) and the vertical distance was 1.20 ± 0.20 cm (range, 0.8–1.5 cm). The critical zone was a circle with 0.5-cm radius, and its center was located 2.5 cm inferolaterally (30 deg) from the lateral canthus. It is very important to understand the motor nerve innervation of the lower eyelid and the “critical zone” to avoid postoperative ectropion or weakness of the lower eyelid resulting from paralysis of the pretarsal or preseptal OOM.