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Biomedical subjects

P J Donald

Publications and source records attributed to P J Donald.

At least 19 recordsLinked to original sources
PubMed1992

Screwdriver aspiration. A complication of dental implant placement.

Endosseous implants are part of the prosthodontic rehabilitation of patients who have undergone radical tumor resection in the oral and maxillofacial area. Several complications arising from the use of these implants have been reported. Intraoperative aspiration of a screwdriver as a rare and life-threatening complication is presented. It was followed by a chain of further complications including pneumothorax, late laryngeal obstruction requiring tracheotomy, and pleural effusion requiring drainage. To prevent similar complications, we recommend general anesthesia when placing dental implants in patients who have previously undergone extended radical tumor surgery of the oral cavity.

Aged↗
PubMed1991

Monoclonal antibody-porphyrin conjugate for head and neck cancer: the possible magic bullet.

Although photodynamic therapy in the treatment of large head and neck cancers showed some initial promise, the results in the final analysis have been somewhat disappointing. Lack of specificity and nonhomogeneous uptake of the porphyrin by the tumor are only some of the problems. The conjugation of a monoclonal antibody (UCD/AB 6.01) with hematoporphyrin derivative that preferentially binds to tumor cells offers promise as a therapeutic agent that will not only improve specificity, but vastly enhances tumor cell kill when exposed to light in its photodynamic range. The application of the monoclonal antibody-hematoporphyrin conjugate (AB:HPD) to A-431 squamous cell carcinoma cells in vitro, followed by exposure to light in the 630 nm range, increases the kill ratio by a factor of 10(5) times. The active tumor cell binding site on the cell surface has been found to be on the microvilli, a site at which a 52 kDa protein that is very similar to keratin 8 is found. The clearance of the conjugate from nude mice who have grown an A-431 tumor shows a retention of AB:HPD of approximately 15% and less than 1% in skin and internal organs when measured at 48 hours. Direct application of AB:HPD to fresh pathology specimens containing human squamous cell carcinomas shows binding exclusively limited to the tumor.

Animals↗
PubMed1991

Radical surgery for nasal cavity and paranasal sinus tumors.

Radical surgery for sinonasal neoplasms in combination with radiation therapy has vastly improved the outlook for these tumors. Magnetic resonance imaging (MRI) combined with high resolution computerized tomography (CT) scanning and recognition of symptoms suggestive of extensive disease has allowed more accurate determination of surgical margins. Long-term follow-up is still needed to define the limits of radical surgery necessary to treat very extensive tumors.

Humans↗
PubMed1990

The pressure exerted by mucoceles in the frontal sinus. An experimental study in the cat.

The pathophysiologic process that results in bone erosion from frontal sinus mucoceles has long been a mystery. Traditionally, bone erosion has been attributed to pressure. However, no scientific evidence has yet been presented to support this hypothesis. To answer this question, seven cats had a mucocele created in one frontal sinus, with the other sinus left as a control. A manometer was inserted into each frontal sinus. Pressure readings were taken over a 7-month period. Pressures on the mucocele side were higher than on the control side and were sufficient to erode bone. Bone was thicker on the mucocele side than on the control side. This study established that mucoceles exert sufficient pressure to erode bone, and that such erosion may be part of a two-stage process.

Animals↗
PubMed1990

Use of the levator scapulae muscle flap in head and neck reconstruction.

There are numerous techniques available for reconstruction of defects following composite resection of oral cavity and oropharyngeal tumors. No single technique is applicable in all situations. The levator scapulae muscle flap is well known for its application in carotid protection. Little attention is paid to its usefulness in other aspects of head and neck reconstruction. We have been using the levator scapulae muscle flap for a variety of reconstructive problems. The flap is useful for buttressing intraoral suture lines, closing intraoral defects, and providing soft tissue to fill in dead spaces and bulk out lateral and anterior oral defects. The levator flap was found to be easy to elevate, safe, and reliable with a minimum of wound complications. A review of 18 patients, representative case studies, and a discussion of surgical technique and relevant anatomy and blood supply is presented.

Aged↗
PubMed1990

Sphenoidal and cavernous sinus resection for tumor.

Malignant neoplasms as well as those with an aggressive locally invasive character involving the sphenoid sinus have been considered heretofore to be inoperable and incurable. Because of fear of entering the cavernous sinus, the proximity of the internal carotid artery laterally and the optic chiasm superiorly as well as the middle fossa contents, these patients were relegated to palliative regimens of irradiation and chemotherapy. As methods have been developed of managing hemorrhage from the cavernous sinus, exposure and control or bypass of the internal carotid artery and combined subcranial and intracranial resection, the frontiers of surgery in the sphenoid sinus have been advanced. We have resected eight patients with tumors involving the sphenoid sinus in whom the walls of the sinus were exenterated, portions of the cavernous sinus removed, the internal carotid artery skeletonized, anterior and middle fossa dura resected, and in a few the temporal lobe was excised. Follow-up ranges from six years to 10 months. There have been no perioperative deaths; one patient succumbed to general inanition with locally recurrent tumor at four months; the rest are all alive and well without evidence of tumor, with the exception of one patient. This patient has a local recurrence anteriorly from an inadequate margin due to a technical error, but there is no recurrence in the sphenoid sinus, the cavernous sinus or the middle cranial fossa.

Cavernous Sinus↗
PubMed1989

Craniofacial surgical resection: new frontier in advanced head and neck cancer.

Craniofacial surgery has revolutionized the management of extensive malignancies and histologically benign but locally invasive tumours which encroach upon or directly invade the undersurface of the brain case. Approaches have been devised for tumours that involve the anterior middle and posterior fossae. Teamwork between head and neck and neurological surgeons is essential. Comprehensive pre-operative evaluation, especially the adequacy of cross-fill of the cerebral circulation via the contralateral arterial system through the circle of Willis, must be done. Management of the internal carotid artery and cavernous sinus presents the most difficult surgical problems during the resection. During the closure, separation of the intracranial dissection from the paranasal sinuses and epipharynx by the use of flaps and grafts is essential to prevent cerebrospinal fluid leakage, cerebral support, and isolation of the carotid and dura from upper respiratory tract organisms. Well-planned and executed craniofacial surgery can be done with acceptable morbidity and mortality rates and reasonable survival rates.

Adenocarcinoma↗
PubMed1988

Frontal sinus fractures: a review of 72 cases.

A retrospective review is presented of 72 patients who sustained frontal sinus fractures (FSF) and were subsequently treated by the department of otolaryngology/head and neck surgery between the years of 1974 and 1986. Eighty-four percent of FSF occurred in males and 71% were a result of motor vehicle accidents. Only 24% remained conscious at the time of trauma, and in only one third of the cases was there no other fracture. Seventy-six percent of FSF involved both the anterior and posterior walls--a figure that possibly reflects the referral patterns to a hospital that is a major regional trauma center. Patients were treated with a variety of procedures including cranialization (42%), osteoplastic flap and fat obliteration (30%), open reduction and internal fixation of the anterior wall (20%), osteoplastic flap and sinus ablation (6%), and intersinus septectomy (1%). Some difficulty was encountered in documenting sustained follow-up, which ranged from 2 months to 9 years, and averaged 22 months. Nine percent of patients died in the post-trauma period. Minor complications were relatively common, but major complications occurred in only 10% of patients. Four patients (6%) suffered meningitis (although the portal of infection was not necessarily through the frontal sinus); one patient (1%) suffered severe pain over the sinus and forehead for at least 12 months after surgery; and a mucocele developed in four patients (6%).

Adolescent↗
PubMed1988

Rhinoplastic implications of maxillary osteotomy.

Maxillary osteotomies are done to correct discrepancies in structural facial harmony. The deformities involve retrusion or protrusion, as well as pathological shortening and elongation of the maxilla. Surgical orthopedics of the maxilla move the nose in part, or in whole, in relationship to the rest of the face. Corrective rhinoplasty is sometimes necessary to correct esthetic discrepancies thus produced, as well as other deformities that may be the usual concomitant of the syndrome addressed by the facial surgery. Le Fort I osteotomies produce more marked changes than pyramidal or Le Fort III type osteotomies, specifically as the tip relates to the dorsum. Segmental osteotomies done to correct discrepancies in vertical height of the maxilla produce specific alterations in the tip-lip relationship.

Acrocephalosyndactylia↗
PubMed1986

Typhus-induced facial necrosis.

A patient with open wounds on his hands developed a severe case of typhus following exposure to a wild rabbit. Typhus resulted in extensive necrosis of the mid-face, including the nasal alae, pinna, and lips. The patient also sustained extensive extremity necrosis. A brief review of the epidemiology, pathophysiology, and treatment of this cause of facial necrosis is presented, as well as a discussion of dopamine gangrene. While this uncommon entity probably played a large part in the necrosis of this patient's extremities, these peripheral lesions are also compatible with typhus.

Adult↗
PubMed1986

Marijuana smoking--possible cause of head and neck carcinoma in young patients.

Six cases of advanced head and neck cancer in young patients, who were regular marijuana users, are presented. Numerous carcinogens, as well as respiratory irritants, are found in marijuana smoke. The active euphoria-producing agent, delta-9 tetrahydrocanabinol, has been implicated in altered DNA, RNA, and protein synthesis and consequent chromosomal aberrations.

Adult↗