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Biomedical subjects

G A Sisson

Publications and source records attributed to G A Sisson.

At least 19 recordsLinked to original sources
PubMed1992

The pectoralis major myofascial flap for intraoral and pharyngeal reconstruction.

The pectoralis myocutaneous flap has been widely used for reconstruction of oral cavity and pharyngeal defects. However, it has several disadvantages, such as chest distortion, hair growth at the reconstructed site, and excessive bulk, all of which can be avoided by the use of the pectoralis myofascial flap. Oral cavities and pharyngeal defects, ranging in size from 4 to 9 cm in largest' dimension, in 26 patients were reconstructed with the pectoralis myofascial flap. All but three defects were successfully reconstructed. The surface of the flap was covered by squamous epithelium in 1 month. The flap remained healthy during and after radiotherapy. The pectoralis myofascial flap is ideal for soft-tissue coverage of small- to medium-size oral cavity and pharyngeal defects. Its major advantages over the pectoralis myocutaneous flap are decreased bulk and improved cosmesis.

Female↗
PubMed1992

Experimental hydroxyapatite cement cranioplasty.

Hydroxyapatite cement is a calcium phosphate-based material that when mixed with water forms a dense paste that sets within 15 minutes and isothermically converts in vivo to a microporous hydroxyapatite implant. This cement was used to reconstruct bilateral 2.5-cm-diameter full-thickness critical-sized parietal skull defects in six cats. One side was reconstructed with 100 percent hydroxyapatite cement, and the other with a mixture of 50 percent hydroxyapatite cement and 50 percent ground autogenous bone by weight. These animals were sacrificed at 6 and 12 months after implantation. Positive and negative controls also were prepared. The anatomic contour of the soft tissue overlying all hydroxyapatite cement implants was well maintained, there were no wound infections or structural failures, and the implants were well tolerated histologically. None of the negative (unreconstructed) control defects was completely filled with repair bone, and all positive (methyl methacrylate) controls demonstrated foreign-body giant-cell formation and fibrous encapsulation of the implants. Examination of decalcified and undecalcified sections revealed progressive but variable replacement of the cement by new bone and soft tissue without a change in the shape or volume of the hydroxyapatite cement-reconstructed areas. New bone comprised 77.3 and 64.7 percent of the tissue replacing the hydroxyapatite cement and hydroxyapatite cement-bone implants, respectively. Replacement of the hydroxyapatite cement implants by new bone is postulated to occur by a combination of osteoconduction and implant resorption. These results indicate that further experimental research leading to the possible application of hydroxyapatite cement for full-thickness calvarial defect reconstruction in humans is warranted.

Animals↗
PubMed1991

Hydroxyapatite cement. I. Basic chemistry and histologic properties.

Hydroxyapatite cement is a unique calcium phosphate preparation that can be shaped intraoperatively and sets in vivo to an implant composed of microporous hydroxyapatite. The histologic response to this cement was evaluated by implanting disks made of this material within the heads of nine cats. Three sets of 12 hydroxyapatite cement disks were produced containing 0%, 10%, and 20% macropores by volume, respectively. The disks were implanted subcutaneously, intramuscularly, above the periosteum of the skull, and directly onto the surface of the calvarium. Each macropore percentage was represented in each tissue plane, and animals were killed up to 9 months postoperatively. There were no toxic reactions, implants extruded, or wound infections. Histologic examination of the implant-soft-tissue interfaces revealed a transient inflammatory response without foreign body reaction. The disks were resorbed over time in direct proportion to their macropore content (surface areas) in all groups except for those disks placed directly onto the surface of the calvarium below the periosteum. In this group, numerous foci of bone formed at the skull-implant interface, with variable replacement of the deep surface of these implants by bone. Implant replacement by bone is postulated to occur through a combination of implant resorption coupled with osteoconduction. Based on these properties, hydroxyapatite cement may prove useful when applied to the reconstruction of non-stress-bearing skeletal tissue.

Animals↗
PubMed1991

Hydroxyapatite cement. II. Obliteration and reconstruction of the cat frontal sinus.

Frontal sinus obliteration and reconstruction can be performed with autogenous grafts or synthetic implants, each of which has significant limitations. Hydroxyapatite cement, which can be shaped intraoperatively and sets to a microporous hydroxyapatite implant, was applied to this problem. Nine cats had the anterior table of their frontal sinus unilaterally removed and the sinus cavity stripped of its mucosa. Hydroxyapatite cement was used to obliterate the cavity and reconstruct the overlying anterior table defect. The unoperated side served as the control, and the animals were sacrificed up to 18 months postoperatively. There were no adverse reactions, infections, mucoceles, or implant extrusions. The normal anatomic contour of the forehead region overlying the hydroxyapatite cement implants was maintained in all animals. Histologic examination of undecalcified whole sinus sections revealed progressive replacement of the implants with woven bone without a loss of volume. Replacement of the hydroxyapatite cement by woven bone is postulated to occur through a combination of implant resorption coupled with osteoconduction. The use of hydroxyapatite cement proved successful for the reconstruction and obliteration of cat frontal sinuses, and may be appropriate for the same application in humans.

Animals↗
PubMed1990

Segmental mandibular regeneration by distraction osteogenesis. An experimental study.

We report the use of distraction osteogenesis for segmental mandibular regeneration. This technique has been used in thousands of patients in the Soviet Union to regenerate as much as 30 cm of tubular bone in the extremities. However, we are unaware of previous experimental or clinical reports of segmental mandibular regeneration by distraction osteogenesis. In a canine model, 2.5-cm segmental mandibular defects were filled with regenerate bone in 25 days at a rate of 1.0 mm/d using bifocal distraction osteogenesis. The diameters of the regenerate segments were comparable with preexisting mandible, and all animals resumed normal oromandibular function following regeneration. The regenerate bone was evaluated radiographically, angiographically, and histologically. In the control group without distraction osteogenesis, the segmental defects failed to fill with regenerate bone. The theoretical basis for distraction osteogenesis, a detailed description of the technique, and a review of previous studies on experimental mandibular lengthening are presented.

Animals↗
PubMed1990

Intraoperative radiation of canine carotid artery, internal jugular vein, and vagus nerve. Therapeutic applications in the management of advanced head and neck cancers.

As a step in the application of intraoperative radiotherapy (IORT) for treating advanced head and neck cancers, preliminary information was obtained on the radiation tolerance of the canine common carotid artery, internal jugular vein, and vagus nerve to a single, high-dose electron beam. Both sides of the neck of eight mongrel dogs were operated on to expose an 8-cm segment of common carotid artery, internal jugular vein, and vagus nerve. One side of the neck was irradiated, using escalating doses of 2500, 3500, 4500, and 5500 cGy. The contralateral side of the neck served as the unirradiated control. At 3 and 6 months after IORT, one dog at each dose level was killed. None of the dogs developed carotid bleeding at any time after IORT. Light microscopic investigations using hematoxylin-eosin staining on the common carotid artery and internal jugular vein showed no consistent changes that suggested radiation damage; however, the Masson trichrome stain and hydroxyproline concentration of irradiated common carotid artery indicated an increase in the collagen content of the tunica media. Marked changes in the irradiated vagus nerve were seen, indicating severe demyelination and loss of nerve fibers, which appeared to be radiation-dose dependent. Four patients with advanced recurrent head and neck cancer were treated with surgical resection and IORT without any acute or subacute complications. The role of IORT as a supplement to surgery, external beam irradiation, and chemotherapy in selected patients with advanced head and neck cancer needs further exploration.

Animals↗
PubMed1990

Endoscopic laser arytenoidectomy revisited.

Arytenoidectomy is currently the most reliable method of treating patients with bilateral vocal cord paralysis. Although both endoscopic and external approaches have been described, the endoscopic laser technique is more desirable because it requires no incision and allows for the immediate assessment of airway size. Eleven patients with bilateral vocal cord paralysis treated by endoscopic laser arytenoidectomy were presented in 1984. At that time, 10 of the 11 patients had been successfully decannulated. Follow-up on that group of patients revealed that 7 of the 10 successfully treated patients remain decannulated with a good airway, although 2 of these patients required a revision procedure to excise a granuloma. One patient failed at 15 months and has failed two subsequent revision operations, and 2 patients have been lost to follow-up. Since 1984, 17 additional patients with bilateral vocal cord paralysis have been treated by the authors using the same endoscopic laser arytenoidectomy technique; all have been successfully managed, with a minimum follow-up of 3 years. The technique of this operation will be reviewed. This study demonstrates the clinical usefulness of endoscopic laser arytenoidectomy in the treatment of bilateral vocal cord paralysis.

Arytenoid Cartilage↗
PubMed1990

Primary extracranial meningiomas of the head and neck.

Extracranial meningiomas comprise approximately 2% of all meningiomas. Primary extracranial meningiomas are even less common. This report details our experience with these unusual tumors from 1972 to 1989. The diagnosis, surgical management, and significant histopathologic features are discussed. The correlation of primary extracranial meningiomas with neurofibromatosis type II and a treatment algorithm are presented.

Adolescent↗
PubMed1989

Hayes Martin Lecture. Do things really change?

The author presents the historical backdrop of the advent of the American Society of Head and Neck Surgery and the Society of Head and Neck Surgeons and their paths that began wide apart and which, over the years, have become closer, even intertwining with the formation of the Joint Council for Approval of Advanced Training in Head and Neck Oncologic Surgery in 1974. The future of head and neck oncology and the role the two societies can play are also commented on.

General Surgery↗
PubMed1989

Paranasal sinus malignancy: a comprehensive update.

A retrospective analysis of 60 cases of paranasal sinus cancer in patients admitted between 1970 and 1985 was undertaken. Forty-six tumors originated in the maxillary sinus, and 14 originated in the ethmoid sinuses. Computed tomography, magnetic resonance imaging, and endoscopic sinus examination aided in early diagnosis of sinus cancer. Computed tomography aided in staging tumors; Caldwell-Luc alone was inadequate for staging tumors invading deeper sites such as the orbits or pterygoid muscle. There were 15 early (T1 or T2) and 31 advanced (T3 or T4) maxillary sinus cancers. Multimodality therapy incorporated radiation, surgery, and chemotherapy. The 5-year survival rate was 49%. We prefer preoperative radiotherapy for advanced lesions and postoperative radiotherapy for early lesions. The use of preoperative radiation therapy has increased our globe salvage rate. All but one of the patients who developed recurrent disease showed recurrence at the primary site prior to developing regional or distant metastasis. Radiation therapy, combined with aggressive surgical management to remove all tumor, provided the best survival rates in advanced lesions.

Adult↗
PubMed1989

1989 Ogura memorial lecture: mediastinal dissection.

The mediastinal dissection was introduced in 1962 to manage an otherwise uniformly fatal problem in head and neck oncology: stomal recurrence of laryngeal, squamous cell cancer. The morbidity and mortality rates continued to be high and the survival rates low, but they were an improvement over those of other treatment plans. Since then, refinements of the ablative techniques and major advances in the reconstructive techniques have significantly decreased morbidity and mortality rates. The most recent data indicate a 45% survival rate at 42 months. It is evident that early diagnosis and staging of stomal recurrences will yield successful results. Because the mediastinal dissection operation is now safe, it should be applied more liberally in head and neck oncology situations such as subglottic extension of laryngeal cancer, advanced thyroid cancers, cervical esophageal and tracheal cancers, and all head and neck tumors with low-nodal disease.

Carcinoma, Squamous Cell↗
PubMed1989

Difficult decisions in endoscopic sinus surgery.

Sinus disease, like many other problems in otolaryngology, may run the gamut of being either easily correctable with a clear-cut treatment or completely resistant to any form of treatment. Fortunately, many patients have problems somewhere between these two extremes. Clearly there is no one correct approach for treatment of many problems. Two, three, or even four approaches may be equally effective in some cases. In other cases, one approach may be successful in the hands of one surgeon whereas another approach is more appropriate for a different surgeon. This article presents nine cases that do not have clear-cut solutions. In some, the consultants clearly disagreed, whereas in others there was some uniformity in treatment plans. This flexibility in surgery in general and specifically with a technique that is relatively new is what makes it so exciting and so promising for continued success in treating sinus disease.

Adult↗
PubMed1988

The prevention of carotid artery rupture with isobutyl-2-cyanoacrylate.

Carotid artery exposure and rupture is one of the most feared complications of head and neck surgery. The ideal method for preventing rupture of an exposed artery should be easy to perform, safe, effective and should spare local and regional flaps for later use in reconstruction. Isobutyl-2-cyanoacrylate (Bucrylate) is a commercially available compound that appears to meet these criteria. Test animals were divided into two groups. The carotid arteries of 12 dogs (group A) were exteriorized bilaterally and coated with Bucrylate unilaterally. Group B (four dogs) underwent the same procedure except that the vessels were bilaterally coated. Wounds were dressed twice daily with moist-to-dry gauze. No antibiotics were given. Nine of the 12 unprotected arteries in group A ruptured within 2 weeks, and one unprotected artery ruptured on postoperative day (POD) 29. Two dogs healed over both vessels. In group B, three dogs ruptured their arteries within 2 weeks. One dog healed over both vessels. Gross and histologic examination of the arteries showed a striking difference between coated and uncoated vessels. We believe that Bucrylate and cyanoacrylate adhesives hold promise in the clinical protection of exposed carotid arteries.

Animals↗
PubMed1987

Mortality and morbidity of gastric 'pull-up' for replacement of the pharyngoesophagus.

Forty-two patients have undergone gastric interposition to replace the pharyngoesophagus; 39 patients had primary or recurrent malignant tumors of the hypopharynx, cervical esophagus, postcrioid area, or tracheal stoma, while three patients had benign disease. The operation consisted of resection of the local neck disease, along with a transhiatal esophagectomy and gastric "pull-up" for restoration of gastrointestinal tract continuity. Eight hospitalized patients died, for a mortality rate of 19%, of which six patients died of complications from local sepsis. The more common nonfatal complications were related to the neck wound, the anastomosis, and the stomach. The complication rate per patient, excluding postoperative deaths, was 40%. The average length of stay was 44 days for the patients with nonfatal complications and 23 days for those without complications. The success rate of the operation with relief of the patients' presenting symptoms was 81%.

Adult↗
PubMed1986

Chin reconstruction with pectoralis myocutaneous flap.

Chin reconstruction after radical surgery for carcinoma of the oral cavity is a complex and controversial problem. We have developed a simple, single-stage, primary procedure for chin reconstruction. It is easily mastered and is based on a simple modification of the pectoralis major myocutaneous flap. Our experience includes seven cases, including two with total chin reconstructions. The number and type of complication is low and consistent with the magnitude of the surgical procedure. This operation provides acceptable aesthetic and functional results to patients undergoing partial or total resection of the chin.

Aged↗