PubMed Health⌕ Search

Biomedical subjects

R J Koch

Publications and source records attributed to R J Koch.

At least 19 recordsLinked to original sources

Laser skin resurfacing.

Laser skin resurfacing has become an important component of rejuvenation surgery. The two wavelengths in common use are: pulsed carbon dioxide and erbium:yttrium aluminum garnet. The principles and techniques of using these lasers for resurfacing and the practice of combining these wavelengths in sequence are described.

Dermatologic Surgical Procedures↗

Microdermabrasion.

Microdermabrasion is a new skin resurfacing modality rapidly gaining popularity among the aesthetic surgery patient population. It produces a superficial wound to the skin, comparable with alpha hydroxy acid treatment clinically and histologically. Advantages include fast results, no anesthetic requirement, safety, and rapid recovery time. Equipment costs and training requirements are modest. Microdermabrasion will likely earn an important place in the skin resurfacing armamentarium.

Dermabrasion↗

Midfacial osteomyelitis in a chronic cocaine abuser: a case report.

We describe the case of a 56-year-old man who was admitted for treatment of a progressive destruction of his hard palate, septum, nasal cartilage, and soft palate that had been caused by chronic cocaine inhalation. Biopsy of the bony septum revealed acute osteomyelitis and an extensive overgrowth of bacteria and Actinomyces-like organisms. There was no evidence of granuloma or neoplasm. The patient received intravenous ampicillin/sulbactam for 6 weeks, followed by lifetime oral amoxicillin. When there was no further evidence that destruction was progressing, the patient underwent nasal reconstruction with a cranial bone graft. The surgery was completed with no complications. To our knowledge, this is the first reported case of midfacial osteomyelitis associated with chronic cocaine abuse. The severity of this patient's complications, coupled with the success of his reconstructive surgery, makes this case particularly interesting. We believe that it is important for physicians to understand that septal perforation in a cocaine abuser should not be underestimated because it could result in a secondary bone infection. Nasoseptal destruction secondary to intranasal cocaine abuse is a result of cocaine's vasoconstrictive properties, and a decrease in the oxygen tension of intranasal tissue can facilitate the growth of anaerobic pathogens.

Administration, Intranasal↗

Growth of tissue-engineered human nasoseptal cartilage in simulated microgravity.

OBJECTIVE: To evaluate the feasibility of in vitro fabrication of tissue-engineered cartilage from human nasoseptal chondrocytes for autologous reconstruction. DESIGN: Hyaline cartilage was reconstituted from chondrocyte-polyglycolic acid scaffolding constructs in a 3-dimensional mammalian cell culture cascade. This included monolayer cellular amplification, cell seeding in the spinner flask, and tissue growth in simulated microgravity. RESULTS: The quality of the fabricated cartilage analogue was found to depend on the initial cell density, duration of incubation, and bioreactor type. Dynamic seeding was nearly completed within the first 10 hours of inoculation regardless of the cell source (cryogenically preserved vs fresh chondrocytes) or presence of serum. A duration of incubation in excess of 4 weeks was required for complete matrix biosynthesis at low seeding densities in the spinner flasks. Seeding densities greater than 2.3x10(6) chondrocytes per scaffold were required for early hyaline cartilage formation as well as longer-time mature matrix regeneration. In addition, maintaining the structural integrity of the unreinforced scaffold, which is necessary for continued mature matrix regeneration, was achievable through postseeding tissue growth in simulated microgravity. CONCLUSION: Once combined with polyglycolic acid scaffolds in the bioreactor cascades that allow efficient seeding and quiescent tissue growth, human septal chondrocytes become a valuable source of reproducible ex vivo cartilage regeneration in the laboratory.

Chondrocytes↗

In vivo model of histologic changes after treatment with the superpulsed CO(2) laser, erbium:YAG laser, and blended lasers: a 4- to 6-month prospective histologic and clinical study.

BACKGROUND AND OBJECTIVE: To compare the in vivo histologic effects of the pulsed carbon dioxide (CO(2)) and erbium:ytrium aluminum garnet (Er:YAG) lasers and to assess the effects of combining CO(2) and Er:YAG laser modalities during a single treatment session. We previously reported 10 patients treated with four laser regimens: CO(2) alone, CO(2)/Er:YAG, Er:YAG alone, Er:YAG/CO(2) with time points at 1 hour and 7 days between laser treatment and histologic analysis. This study found that the optimal treatment consisted of limited CO(2) laser passes followed by Er:YAG. This treatment produced less collagen injury, less thermal necrosis, and more robust epithelial and dermal fibrous tissue regeneration in the acute phase of healing. The present study examines the histologic changes resulting from the host healing response to laser treatment on long-term follow-up of 4-6 months. STUDY DESIGN/MATERIALS AND METHODS: The Stanford University Committee on Human Subjects in Medical Research approved this study. Nine patients with actinic damage and indications for rhytidectomy volunteered for this interventional study in which each patient served as both experimental and control. The right preauricular area was treated at five sites with the following: (1) CO(2), (2) CO(2) followed by Er:YAG, (3) Er:YAG, (4) blended CO(2)/Er:YAG (Derma-Ktrade mark), (5) phenol. Each was subjected to full-face or sub-unit treatment. Each patient was followed up initially daily then weekly for healing of the full-face laser and for differences in healing of the five treatment areas. Five patients were selected for histologic evaluation. At 4-6 months, these patients underwent rhytidectomy with immediate removal of laser-treated skin, which was evaluated histologically by the study dermatopathologist, who was blinded to the treatment at each site. RESULTS: CO(2) laser treatment produced the greatest thickness of neocollagen (0.27 mm; P < 0.05), the highest neocollagen density (P < 0.05), the greatest decrease in elastosis (27%), but took the longest time for healing and resolution of erythema and inflammation (up to 6 months). Er:YAG used alone produced the least collagen density, with the thinnest band of neocollagen (0.08 mm), but the most rapid resolution of erythema and inflammation (within 10 days). Combined CO(2)/Er:YAG treatments, including Derma-Ktrade mark and CO(2) followed by Er:YAG produced histologic changes that were intermediate, as well as recovery that was intermediate (resolution of erythema within 1 month); the development of neocollagen was greater in CO(2)-containing modalities than Er:YAG used alone by a statistically significant margin (P = 0.001). These histologic findings were corroborated by clinical correlation by examination of the five treatment spots in nine patients and in full-face treatments in 100 patients. CONCLUSION: Collagenesis is greatest with CO(2) and least with Er:YAG. Elastosis decreased to the greatest degree with CO(2), least with erbium, and to an intermediate extent with blended CO(2)/Er:YAG regimens (sequential and Derma-K). These changes from control are statistically significant with all regimens (P < 0.05). Blended CO(2)/Er:YAG treatments provide an optimal combination of the benefits of CO(2) but with lesser erythema and healing delay. Clinical and histologic findings change over time for different treatments. Thus, long-term histology is critical for predicting results of treatment.

Algorithms↗

Review of closed dressings after laser resurfacing.

BACKGROUND: Laser skin resurfacing has become an accepted technique for the treatment of facial rhytides and associated solar skin damage. Achieving a successful result is directly related to proper postoperative wound care during the reepithelialization process. There are open and closed approaches to the treatment of the post-laser resurfacing patient with distinct advantages and disadvantages. OBJECTIVE: To review the most commonly used closed dressings after facial laser skin resurfacing and compare their advantages and disadvantages. To compare clinical findings with a group of patients treated exclusively with an open technique. METHODS: Review of composite foams, polymer film, polymer mesh, and hydrogel products and prospective observations of clinical outcomes of patients treated with each dressing category after facial laser skin resurfacing. We perform a retrospective chart review of a group of patients treated exclusively with an open technique comparing crust formation, comfort, and pruritus with the prospective group of patients treated with closed dressings. RESULTS: The closed dressings available today each have unique structural configurations and adhesive properties intended to maintain an occlusive wound environment. Patient acceptance of these dressings was favorable, with improved comfort compared to the open dressing group. Complications of bacterial infections and contact dermatitis were not observed when closed dressings were used with a protocol for dressing changes performed at 48 hours. Rates of reepithelialization did not vary according to dressing category. Crust formation and postoperative pruritus occurred less frequently when closed occlusive dressings were worn by patients. CONCLUSIONS: When used properly, these dressings improve patient comfort, simplify their postoperative wound care, and do not increase the risk of infection or contact dermatitis. Overall satisfaction was highest with perforated mesh and polymer dressings for full-face wounds.

Adult↗

The effect of superpulsed carbon dioxide laser energy on keloid and normal dermal fibroblast secretion of growth factors: a serum-free study.

An in vitro model was used to determine the effect of superpulsed CO2 laser energy on normal dermal and keloid-producing fibroblast proliferation and release of growth factors. Growth factors assayed included basic fibroblast growth factor (bFGF) and transforming growth factor beta1 (TGF-beta1). bFGF is mitogenic, inhibits collagen production, and stabilizes cellular phenotype. TGF-beta1 stimulates growth and collagen secretion and is thought to be integral to keloid formation. Growth in a serum-free medium allowed measurement of these growth factors without confounding variables. Keloid and normal dermal fibroblasts cell lines were established from facial skin samples using standard explant techniques. Samples consisted of three separate keloid and three separate normal dermal fibroblast cell lines. Cells were used at passage 4 to seed 24-well trays at a concentration of 6 x 10(4) cells per milliliter in serum-free medium. At 48 hours, 18.8 percent of each cell well was exposed to a fluence of 2.4, 4.7, and 7.3 J/cm2 using the superpulsed CO2 laser. Cell viability and counts were established at four time points: 0 (time of superpulsed CO2 laser treatment), 24, 72, and 120 hours. Supernatants were collected and assessed for bFGF and TGF-beta1 using a sandwich enzyme immunoassay. All cell lines demonstrated logarithmic growth through 120 hours (conclusion of experiment), with a statistically significant shorter population doubling time for keloid fibroblasts (p < 0.05). Use of the superpulsed CO2 laser shortened population doubling times relative to that of controls; the differences were statistically significant in keloid dermal fibroblasts when fluences of 2.4 and 4.7 J/cm2 were used (p < 0.05 and 0.01, respectively). bFGF was present in greater levels in normal dermal fibroblasts than in keloid dermal fibroblasts. Application of superpulsed CO2 demonstrated a trend toward increased bFGF secretion in both fibroblast types; the increase was significant in the keloid group at 4.7J/cm2. A consistent trend in suppression of TGF-beta1 was seen in both groups exposed to superpulsed CO2, with the maximal effect occurring at 4.7 J/cm2. Serum-free culture sustains logarithmic cell growth and allows growth factor measurement without confounding variables from serum-containing media. Superpulsed CO2 enhances fibroblast replication and seems to stimulate bFGF secretion and to inhibit TGF-beta1 secretion. Given the function of these growth factors, the application of superpulsed CO2 may support normalized wound healing. These findings may explain the beneficial effects of laser resurfacing on a cellular level and support the use of superpulsed CO2 in the management of keloid scar tissue.

Cell Division↗

Histologic analysis of the thermal effect on epidermal and dermal structures following treatment with the superpulsed CO2 laser and the erbium: YAG laser: an in vivo study.

BACKGROUND AND OBJECTIVE: To compare the in vivo histologic effects of the carbon dioxide (CO2) and erbium:yttrium aluminum garnet (Er:YAG) lasers. To ascertain the effects of combining CO2 and Er:YAG laser modalities during a single treatment session. STUDY DESIGN/MATERIALS AND METHODS: Ten patients underwent laser treatment to four left preauricular sites 7 days prior to rhytidectomy as follows: CO2 alone, CO2/Er:YAG, Er:YAG alone, and Er:YAG/CO2. The right preauricular area was identically treated 1 hour prior to rhytidectomy. Laser treated skin was excised during rhytidectomy and was evaluated histopathologically in a blinded manner. RESULTS: After 7 days, all groups were reepithelialized and showed equal neo-collagen formation. After 7 days, CO2/Er:YAG and Er:YAG alone had the least collagen injury and thickest epidermis and papillary dermis of all groups. Specimens lased 1 hour prior to excision showed the least collagen injury and thermal necrosis when treated with CO2/Er:YAG and Er:YAG alone. Four passes with CO2 removed 250 microm of tissue, while eight passes with the Er:YAG removed 160 microm of tissue. CONCLUSIONS: Limiting CO2 laser passes and ending with Er:YAG produces less collagen injury, less thermal necrosis, and more robust epithelial and dermal fibrous tissue regeneration. CO2 followed by Er:YAG has similar thermal necrosis and collagen injury as Er:YAG alone, presumably due to Er:YAG removal of CO2 induced thermal injury.

Dermis↗

Medicolegal aspects of imaging and Internet communications.

Many facial plastic surgeons have set up their own personal World Wide Web (WWW) pages with an electronic mail link to communicate with and educate prospective patients. The possible dilemma is in that these services are provided without actually meeting patients face to face. Also, despite the growing popularity of computer imaging systems, it is not clear whether the medical and legal advantages of using such a system outweigh the disadvantages. The purpose of this article is to evaluate these aspects and to provide some protective guidelines. An examination of possible causes of actions arising from computer imaging suggests that surgeons who follow a few simple guidelines, and who use computer imaging responsibly and cautiously, minimize their legal liability. Issues surrounding Internet discussion groups, posted medical advice, intellectual property, and the use of an electronic mail link are also discussed.

Humans↗

Laser resurfacing of the periorbital region.

Laser skin resurfacing of the periorbital region can be performed as an isolated procedure, as part of a full-face resurfacing, or as an adjunct to procedures such as transconjunctival blepharoplasty. The two wavelengths in common use are pulsed carbon dioxide and erbium: yttrium aluminum garnet. The principles and techniques of using these lasers for periorbital resurfacing, as well as the practice of combining these wavelengths in sequence, are described. In addition, pre- and postprocedure measures are discussed.

Blepharoplasty↗

Controversies in the management of inferior turbinate hypertrophy: a comprehensive review.

Nasal obstruction must frequently be addressed during functional rhinoplasty. Even after a properly performed septorhinoplasty correcting septal deflection and/or nasal valve collapse, nasal obstruction may persist due to turbinate hypertrophy. Turbinates have many important functions, including warming and humidification of inspired air, and numerous factors can contribute to pathologic enlargement. Management of inferior turbinate hypertrophy has been actively debated for more than a century. The primary goal of therapy is to maximize the nasal airway for as extended a period as possible while minimizing complications of therapy, such as nasal drying and hemorrhage. This review describes the various medical and surgical therapeutic modalities widely used today, with emphasis placed on surgical management of the inferior turbinates. Advantages, disadvantages, complications, and controversies of each form of treatment are reviewed and discussed. A staged protocol of increasingly invasive interventions is proposed.

Humans↗

Prevention and correction of temporal hair loss in rhytidectomy.

Routine incisions in the temporal area for rhytidectomy often remove hair-bearing skin anterior to the ear. This results in a cosmetic deformity, making the surgical intervention clearly visible. This is especially problematic for revision rhytidectomy or for patients with naturally high hairlines. This article describes a systematic approach to the temporal hairline and introduces a novel, hair-bearing, transposition flap that corrects iatrogenic loss of the preauricular tuft of hair.

Hair↗

Basic fibroblast growth factor and insulinlike growth factor I support the growth of human septal chondrocytes in a serum-free environment.

OBJECTIVE: To determine if insulinlike growth factor I (IGF-I) and basic fibroblast growth factor (bFGF), individually or in combination, support the growth and viability of human septal chondrocytes in a serum-free medium (SFM) and a serum-enhanced culture medium. DESIGN: Chondrocytes were recovered from enzymatically digested human septal cartilage and were plated for monolayer culture in a newly developed medium. The medium included Dulbecco modified Eagle medium mixed 1:1 with Ham F12 medium and a supplement of known amounts of 2 growth factors-bFGF (100 ng/mL) and IGF-I (100 ng/mL)-used in combination and separately. RESULTS: The combination of IGF-I and bFGF enhanced chondrocyte growth and maintained a high degree of viability in SFM and 10% fetal calf serum. After an initial lag, the SFM, augmented with both growth factors, produced a comparable number of viable cells (4.25+/-0.31 x 10(4)) to that of the medium with 10% fetal calf serum (4.64+/-0.35 x 10(4)) by the seventh day of the experiment. Combined with the 2 growth factors, 10% fetal calf serum provided the greatest proliferation by the end of the experiment. However, the overall mean cell counts for the IGF-I- and bFGF-enhanced SFM were not statistically different. CONCLUSIONS: The combination of IGF-I and bFGF in a serum-free and a serum-supplemented environment supports the growth and viability of human septal chondrocytes in short-term culture. In an SFM, the results obtained approximate those produced in a medium enhanced with 10% fetal calf serum.

Cell Culture Techniques↗

Closed dressings after laser skin resurfacing.

OBJECTIVE: To evaluate the safety, efficacy, and patient acceptance of closed dressings after full facial resurfacing with the carbon dioxide laser. DESIGN: Prospective cohort of men and women undergoing full facial carbon dioxide laser resurfacing. SETTING: Ambulatory surgical center at a university hospital. PATIENTS: Forty consecutive patients randomized to 1 of 4 dressing groups. INTERVENTIONS: All patients underwent full facial resurfacing with a carbon dioxide laser system. One of 5 closed dressings (single- or 3-layer composite foam, plastic mesh, hydrogel, or polymer film) was placed immediately after the procedure. Closed dressings were changed on postoperative day 2 and removed on postoperative day 4. OUTCOME MEASURES: Objective postoperative criteria of erythema, scarring, reepithelialization, and surface irregularities were recorded and photodocumented. Comparisons were made among the closed dressing groups as well as with a group of historical control subjects treated with open dressings. The ease of application, office time for preparation and application, and cost of the individual dressings were collected. Patient characteristics of overall acceptance, comfort, and ease of maintenance were recorded with a visual analog scale. RESULTS: There were no complications of scarring, surface irregularities, or contact dermatitis from the application or maintenance of the closed dressings. There were no significant differences in the number of days of postoperative erythema or in the rate of facial reepithelialization among the groups. Most patients preferred not to continue with the closed dressings past 2 days. Positive features from the use of closed dressings included reduction in crust formation, decreased pruritus, decreased erythema, and decreased postoperative pain, compared with historical controls. Negative features included time in preparation and application of the dressings. Costs ranged from $9.79 to $50 per dressing change. CONCLUSIONS: Closed dressings are safe and offer benefits noted during the first 4 postoperative days. Patients can be expected to maintain a closed dressing for at least 24 hours but no longer than 4 days. The positive features of closed dressings and patient acceptance outweigh the cost and office time involved with their application and maintenance.

Adult↗