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Biomedical subjects

D A Sherris

Publications and source records attributed to D A Sherris.

30 records · Page 2Linked to original sources
PubMed1995

Management of scar contractures, hypertrophic scars, and keloids.

Aberrant fibrous tissue formation after surgery or trauma still presents a challenge to surgeons. Current research hopes to identify the characteristics of the population of fibroblasts that lead to hypertrophic or keloid scar formation. Surgical procedures and laser therapy followed by intralesional steroid treatments still are the foundation of treatment; but new modalities are being applied. The pathogenesis and management of hypertrophic scars, keloids, and scar contractures are discussed in this article.

Cicatrix↗
PubMed1993

The human auricular chondrocyte. Responses to growth factors.

The first human auricular (elastic cartilage) chondrocyte cell culture model is presented. These chondrocytes, harvested from fresh human cadaver auricular cartilage, are easily grown in culture. They produce type II collagen and abundant alkaline phosphatase. Like growth plate chondrocytes, human auricular chondrocytes respond mitogenically to both transforming growth factor-beta and basic fibroblast growth factor by increasing proliferation twofold. The growth factors exert a synergistic effect on thymidine uptake in this model, with maximal stimulation occurring at the dose combination of basic fibroblast growth factor, 10 ng/mL, and transforming growth factor-beta, 3 ng/mL. Human nasal septal (hyaline cartilage) chondrocytes do not increase proliferation in response to these two growth factors. Human auricular chondrocytes also increase matrix production in response to transforming growth factor-beta, as indicated by increased proteoglycan production and increased collagen synthesis. The increased matrix production combined with increased proliferative rate elicited with transforming growth factor-beta and basic fibroblast growth factor indicates that human elastic cartilage chondrocytes harvested from the external ear are better suited for in vitro cartilage implant growth than human hyaline cartilage chondrocytes. Further biochemical and molecular biological characterization of the human auricular chondrocyte cell culture model is currently under way. Additional work is also under way to generate multilayer culture growth on absorbable frameworks, in the pursuit of the long-term goal of in vitro production of autogenous cartilage implants.

Alkaline Phosphatase↗
PubMed1993

Skin excision revision rhinoplasty.

A technique of skin excision revision rhinoplasty is described for application in patients undergoing rhinoplasty. This group of patients includes those with soft-tissue polly beak deformities and a variety of other difficult post-rhinoplasty deformities. Horizontal nasal dorsal skin excision affects tip elevation and eliminates supratip fullness, while vertical midline nasal dorsal skin excision enhances tip definition, decreases dorsal height, and eliminates supratip fullness. We describe several patients who underwent either horizontal or vertical nasal dorsal skin excision for a variety of cosmetic deformities following conventional closed and open rhinoplasty. The techniques presented herein are meant to be added to the list of techniques available to the revision rhinoplasty surgeon rather than to replace existing techniques.

Adult↗
PubMedDate not supplied

Resorption beneath silastic mandibular implants. Effects of placement and pressure.

OBJECTIVE: To evaluate the extent to which silicone rubber mandibular implant (Silastic; Dow Corning, Midland, Mich) pressure and placement (supraperiosteal or subperiosteal) affect underlying mandibular resorption. DESIGN: A randomized, controlled animal trial. SUBJECTS: Ten mixed-breed adult hounds. INTERVENTIONS: Each animal's mandible was implanted with 6 Silastic blocks, 3 inserted supraperiosteally and 3 subperiosteally. Within each grouping of 3 implants, pressure was varied from "minimum" to "moderate" to "maximum" by compressing the implant with titanium miniplates. After 4 months, the animals were killed and their mandibles sectioned for microscopic examination. RESULTS: Mandibular resorption occurred in varying degrees beneath all implants by the end of the study period. The extent of resorption was consistent with retrospective studies in humans. No statistically significant difference was found between supraperiosteal or subperiosteal placement of the implants. However, higher-pressure implants tended to produce less resorption than lower-pressure implants. CONCLUSIONS: While some bone resorption seems inevitable with Silastic mandibular implants, these results would seem to suggest that the placement of implants above or below the periosteum need not be a concern for the surgeon attempting to minimize this consequence. On the other hand, increased pressure may actually decrease resorption, contrary to current assumptions.

Animals↗
PubMedDate not supplied

Quantitative study of nasal tip support and the effect of reconstructive rhinoplasty.

OBJECTIVES: To develop a method to quantify nasal tissue resilience, to establish the normal range for persons without nasal obstruction, and to measure the changes in tissue resilience resulting from standard open rhinoplastic techniques. METHODS: A new device is described that determines nasal tissue resilience. Measurements on the nasal tip were obtained in triplicate at 5 distinct anatomical sites. Normal values (N = 60) were stratified for both sexes into 3 different age groups. Preoperative and postoperative measurements were also obtained in 6 patients who underwent open rhinoplasty for airway obstruction. One patient who underwent intranasal valve repair was included for comparison. All operative patients underwent preoperative and postoperative rhinomanometric measurements. RESULTS: Across all age and sex groups the anterior septal angle is the firmest area of the nasal tip. The mean tissue resilience over the interdomal area and the midcolumella is significantly greater in men than in women. The resilience of the interdomal area exhibits an age effect, with decreasing stiffness over time. The postoperative changes seen correlate well with the placement of structural grafts during rhinoplasty. CONCLUSIONS: Nasal tip support can be quantified. Normative values have been established, which allow one to identify areas of inadequate tip support in persons with nasal obstruction. Alterations in tip support resulting from surgical intervention can be quantified. Open rhinoplasty techniques are an excellent tool to restore deficiencies in nasal tip support.

Adult↗
PubMedDate not supplied

Caudal and dorsal septal reconstruction: an algorithm for graft choices.

The objective of this study is to present an algorithm for choosing graft materials for the reconstruction of severe caudal and/or dorsal septal cartilage abnormalities and to examine the long-term results obtained with these techniques. Retrospective review of 21 consecutive cases of caudal and/or dorsal septal reconstruction via the external approach using the algorithms is presented. The techniques used are carefully described. Patient survey at least 1 year after the initial procedure, rhinologic examination before and after the procedure, and photographic analysis of preoperative and postoperative views are presented. The graft choice algorithm presented helps the surgeon to consider appropriate graft choice alternatives before surgery.

Algorithms↗
PubMedDate not supplied

The versatile autogenous rib graft in septorhinoplasty.

In the graft depleted revision rhinoplasty patient and the patient with major tissue needs, alternatives to septal and conchal cartilage grafts are needed. The costal cartilage graft and rib bone/costal cartilage combination graft are excellent alternatives. In this study 14 patients received 40 grafts from 20 autogenous ribs harvested during septorhinoplasty. Materials were harvested for use as septal replacement grafts, cantilevered grafts, dorsal onlay grafts, columellar struts, and tip grafts. Patient followup was 6 to 31 months, and no evidence of graft resorption or warpage was evident during that period. Complications of harvest were minimal, and harvest techniques are detailed.

Bone Transplantation↗
PubMedDate not supplied

CSF rhinorrhea: 95 consecutive surgical cases with long term follow-up at the Mayo Clinic.

A persistent cerebrospinal fluid (CSF) leak is potentially lethal, and surgical treatment is often required. CSF leak repair is an infrequently performed procedure, and only limited information is available on the long term success of the surgical techniques that are used. This retrospective chart review includes 95 patients who underwent various types of repair surgery for CSF rhinorrhea at the Mayo Clinic. The purpose of this study was to extract factors such as the choice of sealing material, etiology, location of defect(s), surgical approach, and previous procedures, and to analyze their association with the long term success and failure of surgical repair. The mean time interval in this study between unsuccessful surgery and recurrence was 50.8 months, and the mean follow-up 109 months. Among the various approaches, defects repaired endonasally had the lowest recurrence rate. Local nasal mucosa advancement flaps failed more frequently (83.3% failure) than other types of graft material (p = 0.023). These failures took place in a delayed fashion (mean interval until failure: 80 months). Local osteo-mucoperiosteal or chondro-mucoperichondrial flaps (22.2% recurrence rate) and free graft material (15.6% recurrence rate) had the best outcome. The use of fibrin glue to fixate free grafts did not improve the result in this series. Transcranial procedures were associated with a higher complication rate than extracranial procedures (12.9% versus 3.2%). Overall, successful repair was achieved in 91.6% of the patients. We discourage the use of mucosa advancement flaps and advocate free grafts or pedicled osteomucoperiosteal or chondro-mucoperichondrial flaps as sealing material of choice in the majority of cases. The occurrence of delayed failure has to be considered when evaluating reports of CSF rhinorrhea after surgical repair.

Adolescent↗