Biomedical subjects

Sherrell J Aston

Publications and source records attributed to Sherrell J Aston.

4 recordsLinked to original sources

PubMed2005

Designing a virtual reality model for aesthetic surgery.

BACKGROUND: Aesthetic surgery deals in large part with the manipulation of soft-tissue structures that are not amenable to visualization by standard technologies. As a result, accurate three-dimensional depictions of relevant surgical anatomy have yet to be developed. This study presents a method for the creation of detailed virtual reality models of anatomy relevant to aesthetic surgery. METHODS: Two-dimensional histologic sections of a cadaver from the National Library of Medicine's Visible Human Project were imported into Alias's Maya, a computer modeling and animation software package. These two-dimensional data were then "stacked" as a series of vertical planes. Relevant anatomy was outlined in cross-section on each two-dimensional section, and the resulting outlines were used to generate three-dimensional representations of the structures in Maya. RESULTS: A detailed and accurate three-dimensional model of the soft tissues germane to aesthetic surgery was created. This model is optimized for use in surgical animation and can be modified for use in surgical simulators currently being developed. CONCLUSIONS: A model of facial anatomy viewable from any angle in three-dimensional space was developed. The model has applications in medical education and, with future work, could play a role in surgical planning. This study emphasizes the role of three-dimensionalization of the soft tissues of the face in the evolution of aesthetic surgery.

Computer Simulation↗

PubMed2005

Applications of virtual reality in aesthetic surgery.

BACKGROUND: Virtual reality has a long history in plastic and reconstructive surgery, with uses ranging from anatomical demonstration to craniofacial surgical planning. The purpose of this article is to add to the literature a computer graphics-based resource for aesthetic surgery. METHODS: Deformation tools, virtual cameras, and other components of Alias's Maya 4.0 were used to perform virtual surgical procedures on a detailed model of superficial facial anatomy. This three-dimensional model of superficial facial anatomy, derived from the National Library of Medicine's Visible Human Project, was also "aged" in Maya at key depths of anatomical dissection. Adobe's After Effects 5.5 was used for animation postproduction work for all animations. RESULTS: Three-dimensional computer animations were developed to illustrate techniques in aesthetic surgery. Another animation was created that simulates facial aging at various levels of anatomical dissection. CONCLUSIONS: Computer modeling and animation have the potential to play an important role in education, surgical planning, development, and other aspects of aesthetic surgery.

Computer Simulation↗

PubMed2005

An anatomical comparison of transpalpebral, endoscopic, and coronal approaches to demonstrate exposure and extent of brow depressor muscle resection.

BACKGROUND: Approaches for exposure of the muscles of brow depression include transpalpebral, endoscopically assisted, and open coronal techniques. The purpose of this anatomical study was to compare the capacity for visualization and amount of brow depressor muscle resection with each technique. METHODS: The corrugator supercilii, depressor supercilii, medial orbicularis oculi, and procerus muscles were studied by gross anatomical dissection carried out on 24 sides of 12 cadaver heads. First, all visible corrugator and depressor supercilii muscles were resected by means of an upper blepharoplasty incision. Subsequently, a subgaleal endoscopic approach was used to evaluate the extent of resection performed and remove the remaining muscle after transpalpebral corrugator resection. This was followed by coronal exposure to assess the anatomical location and extent of muscle resection accomplished by the two previously mentioned techniques. RESULTS: In all dissections, endoscopy demonstrated that up to one-third of the lateral aspect of the transverse heads of the corrugator supercilii remained following transpalpebral resection. Oblique corrugator head resections were complete, without significant residual muscle following transpalpebral corrugator resection. The procerus muscle was able to be blindly transected by means of the transpalpebral incision but exposed and ablated in all 12 specimens using endoscopy. Coronal exposure demonstrated that no significant amount of corrugator, depressor supercilii, or procerus muscle remained in any of the 12 heads following endoscopically assisted exposure and resection. The medial head of the orbital portion of the orbicularis oculi was visualized and accessible regardless of the technique used. CONCLUSIONS: In 24 anatomical dissections, transpalpebral corrugator resection failed to remove up to one-third of the transverse head of the corrugator muscle. Removal of the brow depressor muscles was accomplished with the endoscopic approach, as confirmed by coronal exposure.

Dissection↗

PubMedDate not supplied

Current methods for brow fixation: are they safe?

BACKGROUND: No single technique for fixation of the scalp after forehead-lift is universally accepted. Complications such as alopecia, loss of elevation, implant palpability, paresthesia, and dural injury are possible with the variety of techniques used currently. This anatomic study was designed to evaluate the thickness of the calvarium at selected points used in brow fixation. The depth of cranial penetration necessary for currently used techniques is measured and compared. METHODS: In a study of 14 fresh adult cadavers, calvarial thickness was measured at selected points (A-F) used in various brow-lifting procedures. This was accomplished by drilling holes in selected points and using a depth gauge to measure thickness. Immediately adjacent to selected points, the cranium is prepared for brow fixation using the following techniques: cortical tunnels, 2.0-mm screw fixation (10, 12, and 14 mm), the Mitek 2.0-mm Quickanchor screw, and the Endotine 3.5 Forehead Device. The depths required for adequate fixation and the potential for cranial penetration through the inner table with all the standard techniques are compared. RESULTS: Depth analysis by mean values showed that sites posterior to the coronal suture (points C-F) were thickest. Depth analysis of sites stratified by gender showed that mean values for the thickness of female skulls were greater than those for males. A review of fixation methods found that cortical tunnels at 45 degrees angles never penetrated the inner table in any of the 14 skulls. Mitek screws never penetrated the inner table, and one Endotine post penetrated the inner table on the left side of one cadaver skull. After placement of 10-, 12-, and 14-mm miniscrews at each of the sites, it was found that three penetrated the inner table. The penetrations all were at far lateral sites, posterior to the coronal suture. CONCLUSION: Variation in skull thickness exists among cadaver specimens at different sites on the skull. In this study, thickness increased medially and posteriorly. Women tended to have thicker skulls than men, and age was not a major variable. This is consistent with findings in previous work. Given the unpublished reports of inner table penetration, with cerebrospinal fluid leak after invasive brow fixation, it behooves the surgeon to keep in mind the anatomy of the calvarium and its nuances.

Aged↗