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Biomedical subjects

S R Baker

Publications and source records attributed to S R Baker.

At least 109 records · Page 6Linked to original sources
PubMed1990

Regional flaps in facial reconstruction.

Soft-tissue defects of the head and neck that are too extensive to be reconstructed with local flaps without excessive impairment of either form or function usually require repair by some type of regional flap. Selection of a specific regional flap depends on the type of defect, i.e., its size and location, and on the intrinsic properties of the regional flap. Single pedicle peninsular or island axial pattern flaps are usually selected because of their improved blood supply compared with random flaps. For most skin defects of the face and neck requiring reconstruction with a regional flap, a medially based deltopectoral flap is usually preferable to musculocutaneous flaps because it is less bulky and produces less donor-site functional impairments. Likewise, for large defects of the upper or lower lip, a deltopectoral flap in most instances is the regional flap of choice for reconstruction. Nasal defects that require regional flaps for repair are reconstructed with various types of forehead flaps. The median flap remains the most useful because the donor site can be closed primarily, leaving a thin midline scar that is camouflaged relatively easily. For nasal defects that require a longer flap that can be provided by a median flap, the oblique forehead flap provides additional length sufficient to reach the base of the columella. Larger defects of the oral cavity and oral pharynx usually require regional or microsurgical flaps for reconstruction of soft-tissue deficits. In addition, mandibular reconstruction may be necessary. The pectoralis major musculocutaneous flap is the author's preferred choice of a regional flap for reconstruction of such defects. The flap readily reaches the oral cavity and oral pharynx and the muscle provides good coverage of the carotid artery when neck dissection has been accomplished. A great advantage of the flap is the ability to achieve reconstruction in one stage without the need for a controlled salivary fistula. Although the deltopectoral flap is the author's preferred regional flap for reconstruction of major defects of the hypopharynx, the pectoralis major musculocutaneous flap is the regional flap of choice when patients are severely malnourished or cachetic. Both flaps provide a source of nonirradiated skin and provide sufficient tissue for total reconstruction of the hypopharynx and cervical esophagus. Both methods of reconstruction, however, have a relatively high rate of stenosis of the distal anastomoses.

Face↗
PubMed1989

Characterization of human laryngeal primary and metastatic squamous cell carcinoma cell lines UM-SCC-17A and UM-SCC-17B.

The squamous cell carcinoma (SCC) cell lines UM-SCC-17A and -17B were derived, respectively, from the primary laryngeal cancer and a metastatic neck tumor of a patient who failed to respond to radiation therapy but achieved long-term remission after surgery. The karyotypes of both cell lines and a subline of 17A were pseudodiploid and stable in multiple in vitro passages. Several karyotypic abnormalities were common to all three cell lines and therefore represent mutations present in the tumor before the divergence of the metastatic and subline populations whereas those rearrangements observed only in one cell are more likely to be secondary. The shared mutations include: duplication of the short and proximal long arm of chromosome 2, isochromosome 3q, duplication 7, inversion 8, duplication of the distal long arm of 18, and monosomy 21 or ring 21. Each line had different rearrangements involving chromosome 7 that resulted in three copies of most of the short arm being present in both cell lines, except for high passages of 17B, in which one structurally normal 7 was replaced by a dicentric isochromosome, dic(7)(q11.22), resulting in four copies of 7p. The dic(7) may represent an in vitro mutation. An isochromosome 13q was noted in both the stemline and subline of UM-SCC-17A but not in UM-SCC-17B. A del(11p) and an iso(21q) were present only in the 17A subline. The cell lines expressed the membrane antigen phenotype characteristic of squamous cancers although the UM-SCC-17A subline differed with respect to three markers. Of these, the A9 and blood group antigen changes are thought to be associated with progression. The subline, which carried the del(11)(p13-p15.1), also failed to express the E7 antigen mapped to the band 11p13. It is possible that the two apparently normal 11s in this subline carry a point mutation or microscopically undetected deletion involving the E7 antigen locus.

Antigens, Neoplasm↗
PubMed1989

Incidence of serum antibody reactivity to autologous head and neck cancer cell lines and augmentation of antibody reactivity following acid dissociation and ultrafiltration.

Serum antibody reactivity to squamous cell carcinoma of the head and neck (SCCHN) was evaluated in 41 autologous serum-tumor cell line combinations using the protein A hemadsorption assay. Autologous antibody reactivity (median titer of 1:4) was detected in sera from 24 of the patients tested. In 10 cases autologous antibody reactivity could be detected only in undiluted serum precluding further analysis. Analysis of higher titer sera from one patient revealed antibodies that define an antigen expressed on autologous tumor cells cultured from both the primary tumor (UM-SCC-17A) and from a metastasis (UM-SCC-17B). Absorption analysis showed that this antigen was also expressed on 6 of 10 allogeneic SCCHN cell lines but not on autologous fibroblasts or on allogeneic melanoma cell lines. Due to the low titer of autologous antibody reactivity in most sera, we sought to determine if dissociation of immune complexes through acidification and ultrafiltration of serum might enhance detectable antibody reactivity as has been done in previous studies in melanoma. Twelve serum samples from eight patients were subjected to acid dissociation and ultrafiltration (AD-U). Only six of the untreated sera had detectable antibody reactivity against the autologous SCCHN cell line whereas following AD-U all 12 sera had enhanced IgG reactivity against autologous SCCHN. Specificity analysis of one serum sample after dissociation revealed that the antibody detected an antigen common to SCCHN cell lines as well as melanoma, glioma, renal, and colon carcinoma cell lines. Circulating immune complexes may provide a reservoir of antibody with potential diagnostic and therapeutic applications.

Antibodies, Neoplasm↗
PubMed1989

Free scapular osteocutaneous flap for mandibular reconstruction.

Seventeen patients, 4 of whom had osteoradionecrosis, underwent mandibular reconstruction with a revascularized scapular osteocutaneous flap. The mean length of revascularized scapular bone used was 10.4 cm. Nine of the 17 flaps healed uneventfully; however, previously irradiated patients had a higher incidence of postoperative complications. There was only 1 flap failure. We found the free revascularized scapular osteocutaneous flap to be reliable and ideal for the reconstruction of large composite defects of the oral cavity.

Adult↗
PubMed1989

Cancer of the oral cavity and Mohs surgery.

Malignant tumors of the oral cavity make up approximately 4% of all cancers occurring in men and 2% in women. In spite of this relatively small incidence, the functional and cosmetic disabilities resulting from this disease produce a profound impact on those stricken. Although the oral cavity is one of the most accessible areas to inspection and palpation, most patients developing oral cavity cancer present with advanced disease. Regional metastases are present in approximately 30% of these patients. A number of therapeutic modalities are available for management of cancer of the oral cavity. The most important include surgical excision, radiation therapy, chemotherapy, or a combination of two or more of these modalities. Surgery and radiotherapy are equally successful in controlling smaller tumors, but advanced tumors are best treated with a combination of surgery and irradiation with or without the addition of chemotherapy. Although combined therapy continues to become more common, it has had little impact on survival rates. Most patients dying of oral cavity cancer die of local regional disease. It is this group of patients that will benefit from newer surgical approaches that can provide an opportunity to increase control of local disease. We believe that an interdisciplinary approach combining the skills of the head and neck oncologic surgeon and the Mohs surgeon may provide a more effective method of controlling oral cancer, while at the same time lessening the functional and cosmetic deformities that frequently result following surgical treatment of this disease. Complete microscopic analysis of all surgical margins (as opposed to random analysis of isolated margins) theoretically should ensure better local control of cancers involving the oral cavity.

Female↗
PubMed1988

Osteocutaneous free scapular flap for one-stage mandibular reconstruction.

Developments in microvascular surgery have overcome much of the problem of inadequate vascularity encountered by more conventional methods of mandibular reconstruction. The advantage of the osteocutaneous scapular flap compared with earlier described revascularized bone grafts or composite flaps is its greater versatility in reconstruction of soft-tissue defects of the oral cavity concomitant with mandibular reconstruction. This is primarily related to the independent vascular pedicles of the cutaneous and osseous portions of the flap. This flap is our preferred method of reconstructing mandibular defects.

Adult↗
PubMed1988

Use of arterialization of the venous system in reattachment of the avulsed auricle.

We attempted to demonstrate that the totally amputated rabbit auricle could survive on nutrient flow provided through arterialization of the venous system. It has been demonstrated by Mundy and Panje that a free flap placed on a large recipient bed and receiving nutrients through retrograde venous flow will survive as frequently as one in which a conventional microvascular anastomosis has been performed. Our groups examined (1) conventional microvascular anastomosis of the amputated appendage to establish survival and demonstrate proficiency with the technique; (2) survival when only venous egress is maintained; and (3) effectiveness of establishing nutrient flow through arterialization of the venous system. Nutrient flow in the first group was through the arterial system. In the second group no nutrient flow was established, but the venous system remained intact. In the last group, nutrient flow existed through retrograde venous profusion. Survival within the groups that underwent reestablishment of nutrient flow through a conventional reanastomosis or through arterialization of the venous system was not significantly different. There were no surviving segments if nutrient flow was not reestablished, but venous channels remained intact. It was shown that nutrient flow to a free-standing appendage can be established through retrograde venous profusion, and that maintenance of venous drainage alone is not sufficient for survival when a limited base exists. We suggest that arterialization of the venous system is a viable means of reestablishing nutrient flow to the amputated auricle.

Amputation, Surgical↗
PubMed1988

Radiologic evaluation of pancreatic ascites.

Two cases of pancreatic ascites are presented in which preoperative endoscopic retrograde pancreatography (ERP) precisely identified the exact location of the leakage of pancreatic juice into the peritoneal cavity. Computed tomography was not helpful in either case. Endoscopic retrograde pancreatography is the most valuable imaging examination to confirm the diagnosis of pancreatic ascites and to direct surgical management.

Aged↗
PubMed1988

Utilizing angiogenic agents to expedite the neovascularization process in skin flaps.

The revascularization of a skin flap after flap transposition is an important step in flap survival. This study investigates the efficacy of certain angiogenic agents to expedite the neovascularization process and to increase the viability of skin flaps. Eighty-four island skin flaps were designed on the auricles of 42 New Zealand White rabbits to achieve 90% necrosis over a 7-day period. Thirty-six flaps were treated with Endothelial Cell Growth Supplement (ECGS) or Endothelial Cell Growth Factor (ECGF) at several concentrations topically or immersed in Gelfoam. The remaining flaps were used as normal saline controls. Flap viability and peripheral neovascularization were documented by polar planimetry, angiography, and histological analysis. The flap viability of the ECGS-Gelfoam -treated flaps was 100% greater than their normal saline-Gelfoam controls (p = .021). Flap angiograms demonstrated increased vascular ingrowth among the treated flaps compared to the controls. This study suggests that angiogenic agents can expedite flap neovascularization and have the potential to increase flap viability.

Administration, Topical↗
PubMed1988

Surgical treatment of pharyngoesophageal spasm.

The clinical course of 17 laryngectomees with pharyngoesophageal spasm who underwent pharyngeal myotomy was studied to determine clinical response and complications. The influence of speech therapy on the development of volitional control of pharyngoesophageal spasm, tracheoesophageal speech fluency, and the efficacy and complications of surgical treatment for pharyngoesophageal spasm were assessed. Volitional control of tracheoesophageal speech was never achieved. Ninety-four percent of the patients (16/17) were successfully rehabilitated following surgical therapy. The complications following pharyngeal myotomy were acceptable.

Esophageal Spasm, Diffuse↗
PubMed1988

Transfacial resection of intracranial tumor.

Tumors of the skull base with intracranial and extracranial components pose special access problems. Traditional craniotomy and extensive external incisions produce morbidity that can be avoided in properly selected cases. Current surgical techniques extend previously described operations to allow good visualization and safe resection through the face for certain intracranial tumors. Meticulous attention to surgical techniques and wide exposure for complete tumor visualization are essential to ensure the safety of these procedures.

Adolescent↗
PubMed1987

Intra-arterial chemotherapy for head and neck cancer. An update on the totally implantable infusion pump.

Intra-arterial chemotherapy for the treatment of localized malignant neoplasms in the head and neck is an appealing approach for several reasons. Perhaps the most important is the possibility of obtaining a regional advantage such that an increased drug concentration is delivered systemically. The patient may, therefore, be spared systemic toxicity. We report our accumulated experience using a totally implantable infusion pump in 37 patients. A total of 42 pumps were implanted: 28 single-catheter pumps and 14 dual-catheter pumps. Radionuclide imaging demonstrated total perfusion of the tumor in all patients. A combination of cisplatin (50 to 100 mg/m2) and floxuridine (0.01 to 0.045 mg/kg/d) was used to treat 26 patients. For these heavily pretreated patients, we observed a 43% complete and partial response rate in the subgroup of patients with squamous cell carcinoma. These results are comparable with those reported for these drugs administered systemically and for other drug combinations tested in the treatment of recurrence disease.

Adolescent↗
PubMed1987

High-dose cisplatin in advanced head and neck cancer.

In 22 patients with advanced squamous cell carcinoma of the head and neck we evaluated the efficacy and toxicity of 200 mg/m2 cisplatin administered in 3% NaCl with vigorous hydration. Six patients had previously untreated stage IV disease and 16 patients had recurrent disease, including eight with prior chemotherapy including low-dose cisplatin and carboplatin. Cisplatin was administered as a brief infusion, either 40 mg/m2/day X 5 or 50 mg/m2/day X4, every 28 days. Objective responses were observed in 16 of 22 (73%) patients, including 5 of 6 (83%) previously untreated patients and 11 of 16 (69%) patients with recurrent disease. This included two complete responses, one confirmed pathologically. Fifty-seven courses of drug were administered and toxicity was monitored with serial creatinine clearance determinations, audiograms, and sensorimotor exams. Neuropathy and ototoxicity were dose-limiting and led to the stopping of treatment in 12 of the 16 responders after one to four courses (median three courses). Only two responding patients continued treatment until disease progression occurred at 3 and 4 months after achieving maximum response. Acute, transient nephrotoxicity occurred in four patients; two were retreated. Moderate myelosuppression occurred in all patients but was not treatment-limiting. For most patients the maximally tolerated number of courses was three. The median survival time was 33.5 weeks for recurrent disease patients, 108 weeks for newly diagnosed patients. This regimen is not recommended for the palliation of recurrent disease. However, the very high response rate suggests that high-dose cisplatin may have a useful role in induction or adjuvant chemotherapy regimens.

Adult↗