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Dive into the research topics where David M. Kahn is active.

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Featured researches published by David M. Kahn.


Plastic and Reconstructive Surgery | 2011

Aging of the Facial Skeleton: Aesthetic Implications and Rejuvenation Strategies

Robert B. Shaw; Evan B. Katzel; Peter F. Koltz; Michael J. Yaremchuk; John A. Girotto; David M. Kahn; Howard N. Langstein

Background: Facial aging is a dynamic process involving the aging of soft-tissue and bony structures. In this study, the authors demonstrate how the facial skeleton changes with age in both male and female subjects and what impact these structural changes may have on overall facial aesthetics. Methods: Facial bone computed tomographic scans were obtained from 60 female and 60 male Caucasian subjects. Twenty male and 20 female subjects were placed in three age categories (20 to 40 years, 41 to 64 years, and 65 years and older). Each computed tomographic scan underwent three-dimensional reconstruction with volume rendering. Edentulous patients were excluded. The following measurements were obtained: upper face (orbital aperture area, orbital aperture width, and curvilinear analysis of the superior and inferior orbital rims), midface (glabellar angle, pyriform angle, maxillary angle, and pyriform aperture area), and lower face (bigonial width, ramus breadth, ramus height, mandibular body height, mandibular body length, and mandibular angle). Results: The orbital aperture width and orbital aperture area increased significantly with age for both sexes. There was a significant increase in orbital aperture size (increase in height of the superomedial and inferolateral orbital rim) in both sexes. The glabellar and maxillary angles decreased significantly with age for both sexes, whereas the pyriform aperture area significantly increased for both sexes with age. Mandibular length and height both decreased significantly for each sex. The mandibular angle significantly increased with age for both sexes. Conclusions: These results suggest that the skeletal morphology of the face changes with age. This change in skeletal morphology may contribute to the appearance of the aging face.


Aesthetic Surgery Journal | 2008

Aging of the bony orbit: a three-dimensional computed tomographic study.

David M. Kahn; Robert B. Shaw

BACKGROUND Facial aging is a dynamic process involving the aging of soft tissue and bony structures. The shape, size, and volume of the bony orbit have all been shown to change with increasing age. OBJECTIVE In this study, we demonstrate how specific bony aspects of the orbit change with age in both male and female subjects and what impact this may have on the techniques used in facial cosmetic surgery. METHODS Facial bone computed tomography (CT) scans were obtained from 60 white subjects (30 female, 30 male). Our study population consisted of 10 male and 10 female subjects in each of 3 age categories. Each CT scan underwent three-dimensional (3-D) reconstruction with volume rendering. Orbital aperture width was measured as a line drawn from the posterior lacrimal crest to the frontozygomatic suture. This line was then used as the x-axis from which the distance to the superior and inferior orbital rim at nine equal increments (labeled 10 to 90) was obtained. The orbital aperture area was also measured on each 3-D model. The Student t test was used to identify any trends between age groups. RESULTS The orbital aperture width and area in both our male and female subjects showed a significant increase with increasing age. There was a significant increase in height of the superior orbital rim medially in both genders, suggesting that the superior orbital rim receded with age in this region. The inferior orbital rim receded significantly laterally in our female population, while our male subjects had a recession of the entire inferior orbital rim. CONCLUSIONS These results suggest that the bony elements of the orbit change dramatically with age, and this, coupled with soft tissue changes, can lead to the appearance of the aged eye and orbit.


Plastic and Reconstructive Surgery | 2010

Aging of the mandible and its aesthetic implications.

Robert B. Shaw; Evan B. Katzel; Peter F. Koltz; David M. Kahn; John A. Girotto; Howard N. Langstein

Background: Facial aging is a dynamic process involving the aging of soft-tissue and bony structures. In this study, the authors demonstrate how specific bony aspects of the mandible change with age in both genders and what impact these structural changes may have on overall facial aesthetics. Methods: Facial bone three-dimensional computed tomographic scans were obtained from 120 Caucasian subjects (60 women and 60 men). Our study population consisted of 20 male and 20 female subjects in each of three age categories (20 to 40, 41 to 64, and ≥65 years). Edentulous patients were excluded. The following measurements were obtained: bigonial width, ramus breadth, ramus height, mandibular body height, mandibular body length, and mandibular angle. The data were analyzed with one-way analysis of variance and two-tailed t tests, with results considered significant at a value of p < 0.05. Results: There was no significant change with regard to bigonial width or ramus breadth across age groups for either gender. Ramus height, mandibular body height, and mandibular body length decreased significantly with age for both genders, whereas the mandibular angle increased significantly for both genders with increasing age. Conclusions: These results suggest that the bony elements of the mandible change significantly with age for both genders and that these changes, coupled with soft-tissue changes, lead to the appearance of the aged lower third of the face.


Facial Plastic Surgery | 2010

Overview of Current Thoughts on Facial Volume and Aging

David M. Kahn; Robert B. Shaw

Facial aging is a dynamic process involving the aging of soft tissue and bony structures. Much is known in regards to how the face loses volume as the soft tissue structures age. Epidermal thinning and the decrease in collagen cause skin to lose its elasticity. Loss of fat, coupled with gravity and muscle pull, leads to wrinkling and the formation of dynamic lines. The aging process has also been shown to affect the facial bones. Multiple studies suggest that the bony aging of the orbit and midface is a process primarily of contraction and morphologic change. This loss of bony volume and projection may contribute to the aged appearance. In this review, we will demonstrate how specific soft tissue and bony aspects of the face change with age in both genders and what impact these structural changes may have on overall facial aesthetics.


Journal of Craniofacial Surgery | 2007

Infant mandibular distraction with an internal curvilinear device.

Jason Miller; David M. Kahn; H. Peter Lorenz; Stephen A. Schendel

Mandibular distraction has proven to be a valuable tool for lengthening the hypoplastic mandible and relieving airway obstruction in infants. Numerous devices have been developed to achieve the desired mandibular lengthening. Complications including poor vector control, need to mold regenerate, facial scarring, external pin loosening, and bulky hardware have been associated with previous devices. In an attempt to circumvent some of these problems, the senior author developed an internal curvilinear device (Osteomed Corporation, Dallas, TX), which is applicable to the infant mandible. The aim of this paper is to describe the use of this distractor as well as its indications and outcomes. Twelve micrognathic infants (ages range from 9 days to 8 months) who underwent mandibular distraction between March 2005-May 2006 at Lucile Packard Childrens Hospital were included in the study. Preoperative workup included an evaluation by a multidisciplinary team including a pediatric otolaryngologist, neonatal intensivist, pediatric pulmonologist, occupational therapist, and craniofacial surgeon. Pre and postoperative maxillomandibular discrepancy, sleep study, feeding evaluation, and three-dimensional computerized tomography scans were compared. All patients tolerated the distraction process well to completion without postoperative complication, except for one patient who had temporary facial nerve weakness, which resolved in 2 months. All patients with obstructive apnea had the obstructive component improved. The last six patients had pre and postoperative polysomnograms to document the improvement. Two patients with neurologic impairment had persistent central apnea. One nonsyndromic patient with inability to feed and feeding-related airway obstruction was taking complete oral feeds 2 weeks after distraction. Mandibular distraction with an internal curvilinear device is effective at relieving airway obstruction in micrognathic infants, while avoiding some previously reported complications.


Plastic and Reconstructive Surgery | 2009

Periorbital skeletal augmentation to improve blepharoplasty and midfacial results.

Michael J. Yaremchuk; David M. Kahn

Background: Narrow palpebral fissures, short lower lids, and full cheeks are hallmarks of youthful periorbita. The presence of these features is predicated on a convex upper midface skeleton. Faces whose midface skeletons are flat or concave do not manifest these youthful attributes, tend to age prematurely, and are prone to lower lid malposition after blepharoplasty. Methods: Augmentation of the infraorbital rim with alloplastic implants can provide convexity to the deficient upper midface skeleton. Suspension of the cheek soft tissues (subperiosteal midface lift) on this now supportive framework narrows the palpebral fissure, shortens the lower lid, and gives fullness to the cheek. The addition of lateral canthopexy to skeletal augmentation and subperiosteal midface lift can restore lower lid position when previous blepharoplasty has resulted in lower lid malposition in patients with deficient midface skeletons. Results: This concept has been utilized in 87 patients (65 female, 22 male) over the last 7 years. Of these 87 patients, four patients (5 percent) required revision surgery to correct implant malposition or prominence. Three patients (3 percent) required implant removal to treat infection. Implants were later replaced in two of these three patients. Conclusions: Augmentation of the infraorbital rim with alloplastic implants provides convexity to the upper midface skeleton. Together with lower lid and midface soft-tissue suspension, it creates or restores youthful periorbital aesthetics.


Plastic and Reconstructive Surgery | 2007

Broad nasal bone reduction: an algorithm for osteotomies.

Ronald P. Gruber; Te Ning Chang; David M. Kahn; Patrick K. Sullivan

Background: A persistent problem with nasal bone osteotomies is inadequate reduction of the width of the nasal dorsum. In addition, an algorithm as to which osteotomy to use has not been fully explored. Methods: Nine cadavers received a medial oblique osteotomy (15 to 30 degrees off midline) following a humpectomy in six. On one side, the osteotomy was performed on the medial side of the apex of the open roof. On the contralateral side, it was performed on the lateral side of the apex. The osteotome was then pried posteriorly. The resultant hemidorsal widths were compared. Clinically, 53 patients were classified into the following: type I, broad nasal base (lateral osteotomy only); type II, broad nasal base and broad dorsum (lateral and medial oblique osteotomy); and type III, broad dorsum only (medial oblique osteotomy only). Results: The reduction in hemidorsal width was greatest when the osteotome was placed on the lateral side of the apex (t test, p < 0.008). The improved width reduction was attributable to the slippage of the lateral nasal bone under the dorsal hood of the nasal bone. A lateral osteotomy did not have to be performed to reduce the dorsal width alone. After 15 to 32 months, nasal bone width was satisfactory in all but three cases, one of which required a revision. Conclusions: Reduction of the nasal dorsal width is facilitated by a medial oblique osteotomy alone if it is placed at the lateral aspect of the apex of the open roof. A classification of broad nasal bones is given that emphasizes the distinction between dorsal width and nasal base width and suggests which osteotomy to use.


Journal of Oral and Maxillofacial Surgery | 2008

Internal Maxillary Distraction With a New Bimalar Device

David M. Kahn; J.A. Broujerdi; Stephen A. Schendel

PURPOSE Distraction osteogenesis of the Le Fort I segment is advocated for patients who require significant advancement of the maxilla or who have a soft tissue envelope compromised by scar tissue. We present a technique for maxillary distraction using an interconnecting intraoral device anchored to the malar prominences above the osteotomy and either the maxilla and/or the dentition below the level of the osteotomy. MATERIALS AND METHODS Ten patients with nonsyndromic cleft lip and palate, mean age of 18, underwent Le Fort I maxillary distraction osteogenesis for management of maxillary hypoplasia. A Le Fort I osteotomy is performed and a Spectrum Intraoral Midface Multi-Vector Distractor (OsteoMed, Addison, TX) is placed leaving a 1 mm to 2 mm distraction gap. After a 2 to 4 day latency period, distraction begins at a rate of 1 mm a day. Once the desired occlusion is achieved the device is left in place for a minimum of 2 months for consolidation. RESULTS Preoperative Sella-Nasion-A point measurements from lateral cephalograms averaged 74 degrees (range, 70-76 degrees). Postoperative Sella-Nasion-A point averaged 81 degrees (range, 75-89 degrees). Preoperative overjet averaged -7.4 mm (range, -3 to -13 mm). Postoperative overjet averaged 2.6 mm (range, 1-3 mm). Average distraction was 9 mm (range, 6-16 mm). The average vertical movement was 7.2 mm in an inferior direction (range, 0-15 mm). The results remained stable at a follow-up of 30 months. CONCLUSIONS We report on distraction of the Le Fort I segment using an internal device. The device design allows the forces of distraction to be shared across a larger surface area delivering a uniform and reliable vector of distraction with increased stability.


Aesthetic Surgery Journal | 2004

Asian-American Rhinoplasty

Ronald P. Gruber; Anna Kuang; David M. Kahn

BACKGROUND Although a number of studies have discussed rhinoplasty of the Asian nose, few have focused specifically on the Asian-American nose, which incorporates characteristics from various Asian nationalities and/or ethnic groups. OBJECTIVE The authors propose a classification system for aesthetic correction of the Asian-American nose and outline surgical techniques with general application to this patient population. METHODS Patients were classified into 3 categories based on morphologic characteristics, as follows: type I (vertical deficiency), type II (vertical deficiency and broad nasal width), and type III (type I or II with glabella deficiency). The treatment protocol included cartilaginous augmentation of the tip, columella, and dorsum for type I patients, using the ear as a donor site. Type II patients underwent similar augmentation and also reduction of the tip and nasal bone, and in some cases reduction of the nasal base. Type III patients received the same treatment as type I or II cases, but in addition required glabella augmentation with hydroxylapatite. RESULTS Representative case studies and results are illustrated for each of the 3 types of patients. CONCLUSIONS A successful approach to Asian-American rhinoplasty should be based on preservation of the patients ethnicity and achievement of facial balance while refining individual facial features. Augmentation of vertical deficiencies is essential to an aesthetic outcome, while glabella correction can be crucial to the overall result in type III patients.


Aesthetic Surgery Journal | 2012

Facial bone density: effects of aging and impact on facial rejuvenation.

Robert B. Shaw; Evan B. Katzel; Peter F. Koltz; David M. Kahn; Edward J. Puzas; Howard N. Langstein

BACKGROUND Facial bone aging has recently been described as primarily resulting from volume loss and morphologic changes to the orbit, midface, and mandible. OBJECTIVE The authors demonstrate how the facial skeleton bone mineral density (BMD) changes with age in both men and women and compare these changes to those of the axial skeleton. They also explore the aesthetic implications of such changes in bone density. METHODS Dual-energy X-ray absorptiometry (DXA) scans of the facial bones and lumbar spine were obtained from 60 white subjects, 30 women and 30 men. There were 10 men and 10 women in each of 3 age categories: young (20-40 years), middle (41-60 years), and old (61+ years). The following measurements were obtained: lumbar spine BMD (average BMD of L1-L4 vertebrae), maxilla BMD (the average BMD of the right and left maxilla), and mandible BMD (the average BMD of the right and left mandibular ramus). RESULTS The lumbar spine BMD decreased significantly for both sexes between the middle and old age groups. There was a significant decrease in the maxilla and mandible BMD for both sexes between the young and middle age groups. CONCLUSIONS Our results suggest that the BMD of the face changes with age, similar to the axial skeleton. This change in BMD may contribute to the appearance of the aging face and potentially affect facial rejuvenation procedures.

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Robert B. Shaw

University of Rochester Medical Center

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Howard N. Langstein

University of Texas MD Anderson Cancer Center

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Peter F. Koltz

University of Rochester Medical Center

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