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Biomedical subjects

Richard Simman

Publications and source records attributed to Richard Simman.

8 recordsLinked to original sources
PubMed2005

Skull base tumors: a comprehensive review of transfacial swing osteotomy approaches.

Numerous techniques have been proposed for the resection of skull base tumors, each one unique with regard to the region exposed and degree of technical complexity. This study describes the use of transfacial swing osteotomies in accessing lesions located at various levels of the cranial base. Eight patients who underwent transfacial swings for exposure and resection of cranial base lesions between 1996 and 2002 were studied. The mandible was the choice when wide exposure of nasopharyngeal and midline skull base tumors was necessary, especially when they involved the infratemporal fossa. The midfacial swing osteotomy was an option when access to the entire clivus was necessary. An orbital swing approach was used to access large orbital tumors lying inferior to the optic nerve and posterior to the globe, a region that is often difficult to visualize. Gross total tumor excision was possible in all patients. Six patients achieved disease control and two had recurrences. The complications of cerebrospinal fluid leak, infection, hematoma, or cranial nerve damage did not occur. After surgery, some patients experienced temporary symptoms caused by local swelling. The aesthetic result was considered good. Transfacial swing osteotomies provide a wide exposure to tumors that occur in the central skull base area. Excellent knowledge of the detailed anatomy of this region is paramount to the success of this surgery. The team concept is essential; it is built around the craniofacial surgeon and an experienced skull base neurosurgeon.

Adult↗
PubMed2005

Improved survival of ischemic random skin flaps through the use of bone marrow nonhematopoietic stem cells and angiogenic growth factors.

Surgical skin flaps are frequently used in plastic and reconstructive surgery to repair acquired or congenital defects. Necrosis is a common complication associated with these flaps postoperatively as a result of inadequate blood supply. Stem cells are precursor cells with the potential to differentiate into more specialized cells. Angiogenic factors act to direct cellular differentiation and organization to form new vascular elements. Our theory was that the combination of angiogenic growth factors with stem cells derived from the subject preoperatively would augment neovascularization, thereby increasing blood supply to the flap, which may ultimately improve flap survival. In phase I, 40 Lewis rats were randomized into 4 groups of 10. Random dorsal skin flaps were elevated and treated at the same time. The first group was injected with only medium, the second with stem cells, the third with stem cells and angiogenic factors, and the fourth with angiogenic growth factors. Millimetric measurements of flap viability at 7 and 14 days did not show any statistically significant differences between the studied groups. In phase II, 24 rats were also randomized into 4 groups of 6, but this time were treated 1 week before flap elevation. The viability measurements showed an increased rate of viability in the group in which stem cells and the angiogenic factors were administered simultaneously (84.5% +/- 3.2%) as compared with the unmodified control group (62.6% +/- 7.3%) or to the groups in which only precursor cells (60.4% +/- 7.9%) or angiogenic factors (62.3%+/- 10.1%). Increased blood supply brought by these manipulations is believed translated to increased tissue flap survival. Punch biopsies showed that "green fluorescent protein"-labeled precursor cells was noted to form luminal structures in the treated flaps. The vascular cast of all flaps was filled with Mercox plastic resin. After euthanasia, the soft tissues of the harvested flaps were dissolved and the remaining vascular cast was weighted. The weight-based ratio of the vascular composition was determined. The flaps injected with both stem cells and angiogenic factors showed higher values. We conclude that the administration of bone marrow stem cells with angiogenic factors 1 week before flap creation improves the survival of ischemic random skin flaps.

Angiopoietin-1↗
PubMed2005

Dermatofibrosarcoma protuberans of the face: surgical management.

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive, rarely metastatic, spindle cell tumor. It is most commonly found on the trunk and rarely on the head and neck. Recurrence has been found to be more common in the head and neck region, which may be attributable to delayed patient presentation or a reluctance for wide excision in that region. The authors report a rare case of DFSP presenting as a large mass of the face. Surgical treatment required aggressive local resection of the tumor, including the underlying maxillary antrum. The soft tissue was cleared by Mohs technique. More than one procedure was required to obtain clear bone margins. Adjuvant radiation therapy was used to gain local control. Reconstruction was performed using a cheek advancement flap, as well as a forehead flap and split-thickness graft to the donor site.

Dermatofibrosarcoma↗
PubMed2004

Medial plantar arch pinch grafts are an effective technique to resurface palmar and plantar wounds.

Resurfacing the glabrous skin covering the human plantar and palmar surfaces constitutes a challenge to the plastic surgeon. Ideally, when this skin is lost, it should be replaced by the same type of tissue to provide strength, texture, and color match. This paper describes our experience with 9 palmar and plantar wounds which were successfully resurfaced with pinch grafts harvested from the non-weight-bearing area at the medial plantar arch of the foot. The patients were allowed to ambulate after surgery with partial or full weight-bearing as tolerated, the donor sites healed in 7 to 9 days without complication, and pinch grafts took 100%. The grafted wounds were completely covered with 1 application once the grafts reached confluence. Not only was pain eliminated, but the patients also were able to ambulate and use their hands with minimal reservation 2 weeks after surgery. Fourteen-month follow-up examination showed reliable and durable results, with perfect tissue match and no contracture. This technique is easy to perform in the office under local anesthesia. It is safe and well tolerated by the patient.

Adult↗
PubMed2003

Effect of mitomycin C on keloid fibroblasts: an in vitro study.

Keloids are the result of aberrant wound healing of human skin after dermal injury. Therapeutic options include excision followed by radiation therapy, steroid injection, and compression with silicone sheets among others. Local invasion and recurrence after excision has provoked interest in treating keloids as neoplasms. The purpose of this study was to determine the effect of mitomycin C (MMC) on keloid fibroblasts. Keloid fibroblasts obtained from five different patients were exposed to MMC. A control group of normal and keloid cells was treated with phosphate buffered saline only. Contrast microscopy showed a decrease of fibroblast density during the 3 weeks after exposure for normal and keloid fibroblasts relative to untreated fibroblasts. This was confirmed by total cell counts ( = 0.1) and measurement of DNA synthesis. By the third week, there was a recovery in DNA synthesis and increased cell count for some of the treated fibroblasts. We concluded that at an appropriate concentration, MMC shows proliferation of keloid fibroblasts in vitro for a period of 3 weeks. This agent may be considered in clinical trials after surgical excision of keloids.

Cell Division↗
PubMed2002

Prefabricated buccal mucosa-lined flap in an animal model that could be used for vaginal reconstruction.

Congenital vaginal aplasia, gynecological tumor excision, and male-to-female sex surgery are three clinical conditions in which the plastic surgeon is involved in vaginal reconstruction. Skin-lined or skin-grafted local flaps are currently used, but for many reasons, keratinized skin is not the ideal lining for such a moist cavity because it leads to dryness, desiccation, maceration of the skin, and even hair growth in the cavity. The purpose of this study was to create a subcutaneous cavity lined with mucosa in an area with a predictable blood supply. The abdominal area supplied by the deep circumflex iliac vessels was chosen. Six minipigs were used. Strips of tongue buccal mucosa formed the lining; if additional tissue was required, it was taken from the mucosal aspect of the cheek. The mucosa was expanded by using multiple stab incisions. The mucosa was sutured onto the fascia supplied by the deep circumflex iliac vessels, and the skin incision was closed over a silicone sheet to prevent adhesion to the underlying mucosa. This was left for 1 week to allow the mucosa to take. The prefabricated fascial flap was rolled over a silicone stent and was closed longitudinally to form a cylindrical shape. The flap was placed in a subcutaneous pocket in the right inguinal area. The caudal end was left open and was sutured to the surrounding skin. The silicone stent was used to keep the cavity patent and to prevent adhesions in the early stage of the healing process. Regular digital examination was performed to assess patency and contour; endoscopy allowed assessment of mucosa viability. This method of producing a mucosa-lined flap may provide a solution to the difficult problem of vaginal reconstruction.

Animals↗