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Biomedical subjects

Samuel M Lam

Publications and source records attributed to Samuel M Lam.

27 records · Page 2Linked to original sources
PubMedDate not supplied

A systematic histologic analysis of nonablative laser therapy in a porcine model using the pulsed dye laser.

BACKGROUND: To our knowledge, no systematic analysis of nonablative laser therapy has been performed. OBJECTIVE: To alter the parameters (fluence, spot size, pulse duration, and use of cooling spray) for the pulsed dye laser to determine the precise settings that would yield the most favorable dermal remodeling in a porcine model. METHODS: Research was conducted in an animal laboratory at Albany Medical College. An anesthetized Yucatan miniature pig was subjected to a pulsed dye laser at various parameters. After 10 weeks, the laser-treated areas were harvested and processed for blinded, randomized, histologic evaluation. Negative (nontreated skin) and positive (ablative carbon dioxide laser-treated skin) controls were compared with the nonablative pulsed dye laser-treated areas. MAIN OUTCOME MEASURES: Quantitative assessment of collagen band width and cells per high-power field and qualitative assessment of epidermal and dermal changes. RESULTS: A significant difference (P<.001) in collagen band width was evident when nonablative laser-treated skin and carbon dioxide ablative laser-treated skin specimens were compared with untreated skin specimens, but no significant (P =.18) difference existed between the nonablative and ablative modalities. Similarly, cellular hypertrophy, as measured by high-power field, corroborated the previous findings. Furthermore, a higher fluence, a larger spot size, and a longer pulse duration proved statistically significant for increased collagen band width (P =.01, P<.001, and P<.001, respectively), and a larger spot size and a longer pulse duration exhibited significance for cells per high-power field (P =.02 and P =.009, respectively), with a trend toward significance for higher fluence (P =.09). Overall, the dermis was considerably thicker for nonablative and ablative laser-treated areas compared with untreated skin, but this could not be quantified because the depth exceeded the punch biopsy instrument. The epidermis remained unchanged. CONCLUSIONS: The nonablative pulsed dye laser has demonstrated favorable histologic evidence of dermal remodeling, and its effects were similar to histologic changes seen with the carbon dioxide ablative laser, both of which were statistically significant compared with untreated skin, as seen in this preliminary animal model.

Animals↗
PubMedDate not supplied

A psychological profile of children with hemangiomas and their families.

OBJECTIVE: To assess the psychosocial impact of hemangiomas and their treatment on children with the disease and their families. DESIGN: Thirty-nine children who were treated for hemangiomas were examined by a questionnaire that addressed the emotional attitudes of the parent and child toward the disease and the related treatment. SETTING: Two private ambulatory surgery centers (in Latham and Charleston). RESULTS: Overall, the survey found a negative effect on the child's family, with considerable fear caused in part by adverse public commentary or attitudes--which was ameliorated by education from the primary care provider and specialist. However, the family's perception was that the child was not deeply affected by his or her condition and that treatment (laser, intralesional corticosteroids, oral corticosteroids, surgery, or a combination) did not change the child's emotional response to the disease. However, most parents observed that their child was too young to appreciate his or her malady. CONCLUSION: Given earlier intervention for children with late-involuting hemangiomas and the advent of more effective therapies, our survey did not seem to indicate that the children experienced significant emotional trauma from their condition; nevertheless, their families experienced appreciable emotional and psychological distress.

Adult↗
PubMedDate not supplied

Management of an arteriovenous malformation.

Arteriovenous malformations represent a unique challenge to the facial plastic and reconstructive surgeon. Unlike other vascular anomalies, such as hemangiomas or capillary vascular malformations (or port-wine stains), true arteriovenous malformations are rare aberrations in vascular morphogenesis. Their rarity and high propensity toward bleeding and recurrence combined with the potential for life-threatening rupture may make the occasional surgeon who dares to resect these lesions rightfully less than intrepid in his endeavor.

Arteriovenous Malformations↗
PubMedDate not supplied

Midfacial rejuvenation via a minimal-incision brow-lift approach: critical evaluation of a 5-year experience.

OBJECTIVE: To evaluate the surgical technique, cosmetic results, and complications of patients who underwent a midface-lift via a minimal-incision brow-lift performed by the senior author (E.F.W.). SETTING: Private, ambulatory surgical center. DESIGN: A retrospective review of 325 midface-lifts performed over a 5-year period by a single surgeon. Patients A total of 325 consecutive patients who underwent a midface-lift, with or without concurrent rhytidectomy and other adjunctive procedures, and who completed 3 months of follow-up were reviewed for perioperative complications. One hundred patients who had complete photographic and chart records and who had a minimum of 6 months of follow-up were randomly selected for photographic rating and chart review. Of the patients who had a minimum of 1 year of follow-up, 50 were randomly selected to determine if midfacial elevation led to any evidence of lateral-canthal distortion. MAIN OUTCOME MEASURES: Midfacial elevation was assessed in 3 facial zones by 3 independent evaluators. Zone I represents the malar-infraorbital complex; zone II, the nasolabial sulcus; and zone III, the jawline. The zones were rated on a scale from 0 to 2 (0, no improvement; 1, mild improvement; and 2, marked improvement). Change in the lateral-canthal position was measured in the vertical and horizontal axis for each eye. All complications were recorded. RESULTS: The 3 independent evaluators correlated well in their scores (kappa = 0.643) and found that most patients showed the best improvements in zone I, with 70% of patients showing marked improvement (P<.001). Moderate improvement was noted in zone III (marked improvement, 30%; mild improvement, 50%; and no improvement, 20%). Little or no improvement was noted in zone II (marked improvement, 4%; mild improvement, 60%; and no improvement, 36%). Patients who underwent a rhytidectomy along with a midface-lift showed better elevation in zone III. However, patients who underwent a brow/midface-lift alone also showed favorable improvement along the jawline (zone III). Although the postoperative lateral-canthal position revealed statistically significant vertical elevation of the lateral canthus on the right side, this finding did not correlate with any perceived clinical significance by the reviewer or patient (P<.01). Temporary morbidity included 2 subperiosteal abscesses and 3 frontal and 1 buccal facial nerve neuropraxias that resolved by 6 months. Permanent complications included 1 case of unilateral cranial nerve V2 paresthesia. Five patients had alopecia requiring scar revision. Many of these complications, including subperiosteal abscess and alopecia, have subsequently been avoided by minor technique modifications. CONCLUSION: The technique of midface-lift via transbrow approach is a safe, reliable method of midfacial rejuvenation and avoids the unnatural lateral-canthal distortion previously described in the literature.

Adult↗