Biomedical subjects

D E Mattox

Publications and source records attributed to D E Mattox.

At least 19 recordsLinked to original sources

PubMed1992

Complications and early outcome of anterior craniofacial resection.

OBJECTIVE: To evaluate the complications of anterior craniofacial resection and correlate their impact with tumor control status. DESIGN: We conducted a retrospective review of 32 consecutive, operable patients' records seen over a 6-year period, requiring 35 procedures. SETTING: Academic tertiary referral medical center. PARTICIPANTS: Twenty-six patients (81%) had malignant lesions (esthesioneuroblastoma, squamous cell carcinoma, and a group of miscellaneous malignant tumors). Six patients had various benign neoplasms. INTERVENTION: The surgical approach involved bifrontal craniotomy coupled with lateral rhinotomy in 19 cases (61%), facial degloving in 10 cases (32%), a total rhinectomy in one case, and endoscopic sinusectomy without facial incision in two cases. OUTCOME MEASURE: Clinically noted complications and oncologic outcome. RESULTS: There was one avoidable perioperative death indirectly associated with the patient's procedure. Nine patients suffered significant intracranial neurological complications such as tension pneumocephalus and delayed epidural abscess. All of these complications were managed successfully. Of patients with malignant tumors, 13 (52%) are alive with no evidence of disease and one is alive with recurrence after a mean follow-up period of 28.9 months. The 10 patients who succumbed to disease had a mean postoperative survival of 22.9 months. CONCLUSIONS: In contrast to the perspective of only a decade ago, we conclude that craniofacial resection is a relatively safe, versatile, and effective procedure for surgical management of tumors involving the anterior skull base.

Adult↗

PubMed1992

The utility of magnetic resonance imaging in the diagnosis of intranasal meningoencephaloceles.

We present three patients in whom the diagnosis of intranasal meningoencephalocele was made by magnetic resonance imaging. The initial clinical evaluation and computed tomographic examinations of these patients failed to distinguish between chronic inflammation and intranasal meningoencephalocele. Although both computed tomography and magnetic resonance imaging are used to distinguish between normal, inflammatory, and neoplastic tissue in the nasal cavity and paranasal sinuses, limitations do exist and these are the focus of our communication. A clear understanding of the efficacy of these radiographic modalities will enhance surgical planning and can preclude severe complications.

Encephalocele↗

PubMed1991

Sutureless vascular anastomosis with biocompatible heat-shrink tubing.

We have tested a new method of vascular repair using biocompatible, low-temperature, heat-shrinkable tubing on canine carotid arteries. All of 16 canine carotid arteries were patent immediately after the anastomosis. None of the anastomoses leaked after the clamps were released. Average time from severing the vessel to releasing the clamps was 12 minutes. At 2 weeks, nine of 12 vessels were patent; the three failures were attributed to infection of a seroma that occurred in all of the dogs' necks. Histologic evaluation of the uninfected cases showed no inflammatory exudate around the prosthesis. Macroscopic and electron microscopic examination confirmed healing of the endothelium across the anastomoses. Sutureless vascular anastomosis with biocompatible heat-shrink tubing is a potential new modality for the acute repair of severed vessels.

Anastomosis, Surgical↗

PubMed1991

The effects of polyamines and polyamine inhibitors on rat sciatic and facial nerve regeneration.

The effects of exogenous polyamines and polyamine biosynthetic pathway inhibitors on regenerating nerves were examined in adult male rats following nerve transection and surgical repair. Several studies have demonstrated the efficacy of exogenous polyamines in promoting the functional recovery of peripheral nerves following crush or freeze injuries in the rat. In order to simulate clinical peripheral nerve surgery, we studied these effects after complete nerve transection and evaluated regeneration by counting axons. There was no statistical difference in axon number with and without polyamines and in the presence of inhibitors and inhibitors with end product addition. Our study suggests that the difference in recovery seen in previous studies is not mediated by a change in axon number.

Animals↗

PubMed1991

The effects of DFMO on polyamine metabolism in the inner ear.

Difluoromethylornithine (DFMO) is a novel antineoplastic agent that was associated with an unexpected hearing loss in Phase II clinical trials. DFMO interferes with polyamine synthesis by inhibition of the enzyme ornithine decarboxylase (ODC). The objective of the current study was to establish a methodology to determine the effect of DFMO on polyamine levels and ODC activity in the cochlea. Guinea pigs received DFMO in their drinking water and were tested for auditory brainstem response threshold shifts. The organ of Corti, the lateral wall, and the acoustic nerve were assayed for both ODC activity and polyamine levels. In DFMO treated animals there was an inhibition of ODC activity in cochlear tissues as well as in intestinal mucosa. In addition, a significant depletion of cochlear polyamines was observed in the treatment animals. This study suggests that systemically administered DFMO inhibits ODC activity and interferes with polyamine synthesis in the cochlea.

Animals↗

PubMed1991

Central nervous system changes associated with noise-induced hearing loss: an electron microscopic and freeze-fracture study of the chick nucleus magnocellularis.

This investigation assessed the effects of noise-induced hearing loss on the avian nucleus magnocellularis, the homologue of the mammalian cochlear nucleus. Fifteen-day-old chicks were exposed to high-intensity broad-band noise (132 dBA) for 24 to 72 hours. Hearing loss was documented with auditory brain-stem response recordings and scanning electron microscopy of the basilar papilla. Nucleus magnocellularis was assessed with thin-section electron microscopy and freeze-fracture techniques. Freeze-fracture preparations of noise-exposed animals showed a decrease in synaptic vesicle fusion sites at the synaptic active zone, a decrease in re-uptake of presynaptic membrane by coated vesicles, and a shift of the preferential fracture plane at the synapse from the presynaptic membrane to the post-synaptic membrane. These findings support the hypothesis that the effects of noise are not limited to the auditory periphery, but that transneuronal changes extend into the auditory central nervous system.

Animals↗

PubMed1991

Repair of peripheral nerves of unequal diameters.

Four techniques for anastomosis were investigated for the anastomosis of a large proximal segment to a smaller distal segment of rat peripheral nerve with a size disparity of approximately 3 to 1. The techniques were perineural sutures (group I), KTP laser annealing (group II), collagen tubes with a 5-mm gap between the nerve segments (group III), and collagen tubes without a gap between the nerve ends (group IV). At 6 weeks there were no gross nerve distractions in groups I or IV. There were two failures in group II and three in group III. The percentage of fibers that crossed intact anastomoses were: group I, 89%; group II, 75%; group III, 115%; group IV, 125% (P less than .05 for the collagen tube repairs). Our results indicate that the suture technique is still the most reliable method of nerve repair. However, collagen tubes were effective in increasing the percentage of axons crossing the anastomosis.

Anastomosis, Surgical↗

PubMed1991

Management of the facial nerve in skull base surgery.

The facial nerve presents a significant obstacle to adequate surgical exposure of lesions involving the skull base. The evolution of various surgical approaches to the jugular foramen, petrous apex, and lateral facial approaches to the skull base aimed at preserving the seventh cranial nerve are reviewed. Methods and techniques in management of the intratemporal and extratemporal facial nerve are discussed.

Facial Nerve↗

PubMed1991

Experimental nerve regeneration. A review.

The aim of peripheral nerve repair is to restore motor and sensory function, which requires more than just 10-0 sutures and a good microscope. The past decade has seen an explosion in the understanding of how nerves grow, and this information is being used to develop better treatments for nerve injuries. In the future, treatment will not be limited to the operating room, because postoperative adjuvant therapies will become increasingly more important in the management of nerve repairs. At the same time, advancement in manufacturing techniques, a better understanding of biomaterials, and the use of the laser will replace the time-honored techniques of surgical repair in many clinical settings.

Animals↗

PubMed1990

Southwest Oncology Group study of mitoxantrone for treatment of patients with advanced adenoid cystic carcinoma of the head and neck.

Eighteen patients are evaluable for response in a Phase II trial of Mitoxantrone for advanced adenoid cystic carcinoma of the head and neck. One patient had a complete response; there were no partial responses. Twelve patients had stable disease for 3 or more months. There was no significant anti-tumor activity of Mitoxantrone in the group of patients with adenoid cystic carcinoma, all of whom were previously heavily treated with surgery, chemotherapy and/or radiation therapy.

Adult↗

PubMed1990

Cochlear damage and increased threshold in alpha-difluoromethylornithine (DFMO) treated guinea pigs.

Alpha-difluoromethylornithine (DFMO) inhibits polyamine synthesis and is used as an antineoplastic and antiparasitic drug. In early human trials DFMO unexpectedly caused a sensorineural hearing loss. In the current study DFMO was administered to guinea pigs to investigate its effects on organ of Corti histology and on auditory thresholds. Histologic examination revealed that DFMO caused greatest damage in the hook and first turn. Damage in the second and third turns was minimal. Animals treated for 12 weeks with DFMO differed significantly (P less than 0.05) from controls in the hook and first turn in that: 1) DFMO caused a loss of hair cells in all rows. Loss of inner hair cells was greater than that of outer hair cells. 2) The remaining outer hair cells were shorter and contained a greater number of Hensen bodies. 3) The Deiters' cell bodies were longer and this increased length was associated with the decreased length of the corresponding outer hair cells. Brainstem audiometry showed that DFMO produced a hearing loss and the magnitude of this loss increased over twelve weeks of DFMO administration.

Aminoglycosides↗

PubMed1990

Endoscopic management of cerebrospinal fluid leaks and cephaloceles.

The excellent visualization and atraumatic surgical techniques of endoscopic sinus surgery have been applied to the management of five cerebrospinal fluid leaks and two nasal cephaloceles. In all cases, the exact site of the lesion was identified. Four cerebrospinal fluid leaks were grafted with a free or pedicled septal mucosal graft. The fifth cerebrospinal fluid leak came from a narrow sphenoethmoid recess and stopped after the mucosa was abraded. The two cephaloceles were reduced intranasally and covered with bone and mucosal grafts. Not all cases seen in the same time period were treated endoscopically; two additional cerebrospinal fluid leaks were treated with conventional techniques because of severe nasal inflammatory disease and intracranial complications. The technique and indications for endoscopic management of cerebrospinal fluid leaks and cephaloceles are discussed.

Adult↗

PubMed1990

Uncommon tumors of the skull base and uncommon approaches to them.

The recognition of a number of uncommon tumors of the skull base is now relatively simple because of three-dimensional computed tomography and magnetic resonance imaging with enhancement. The radiographic classification of these tumors is reviewed, and their treatment is discussed. Although the basic approach to these tumors is the same--radical surgery with decompression of neural and vascular structures--the authors present various operative techniques for gaining access to and removing these tumors. They also examine the role of radiotherapy in supplementing surgical treatment.

Craniotomy↗

PubMed1990

Tumors of the skull base.

Recognition of the many benign and malignant tumors that occur in the skull base is now simple, given three-dimensional CT scanning and MRI with enhancement. Recent developments in surgical technique have allowed these tumors to be approached, but only in the past two to three years has radical surgery been possible.

Chondroma↗

PubMed1989

High-dose cisplatin for locally advanced or metastatic head and neck cancer. A phase II pilot study.

High-dose cisplatin (40 mg/m2 every day X5) was administered to 14 patients (11 men, three women) with locally advanced or metastatic head and neck cancer not curable by surgery or refractory to previous chemotherapy and/or radiation therapy. All 14 patients were evaluable for toxicity; one patient was inevaluable for response due to early death. A total of 24 courses of therapy were administered. The dose-limiting toxicity was myelosuppression with 73% of patients experiencing Grade III or IV neutropenia. Grade II or above thrombocytopenia occurred in 30% of the patients. Renal and neurologic toxicity was minimal. Two patients experienced laryngeal edema from vigorous hydration with one of them requiring a tracheostomy for respiratory compromise. Partial responses were seen in six patients (46%). Two of the six patients had received previous treatment with standard dose cisplatin. Two patients achieved long-term responses (54+, 44+ months, respectively). Both of these patients were previously untreated, inoperable (T4N3M0, T3N1M0), and subsequently received radiation therapy after two cycles of chemotherapy. Median duration of response in the remaining responders was 3 months (range, 3-10 months). High-dose cisplatin may benefit selected patients with inoperable, advanced head and neck tumors. However, further randomized trials need to be conducted before firm conclusions can be established.

Adult↗

PubMed1989

An animal model of hearing loss from alpha-difluoromethylornithine.

alpha-Difluoromethylornithine is a new antineoplastic and antiparasitic drug that inhibits the synthesis of polyamines. It causes a sensorineural hearing loss in humans. We have established an animal model for alpha-difluoromethylornithine-induced hearing loss. The time course for onset and recovery of the hearing loss in animals was similar to that seen in humans. Electrophysiologic and histologic data suggest that the anatomic site of alpha-difluoromethylornithine-induced hearing loss is the organ of Corti. Unlike other drugs with ototoxic effects, the specific enzymatic site of action of alpha-difluoromethylornithine is known, making it a potentially important tool in auditory research.

Animals↗

PubMed1989

Effects of fibrin glue on rat facial nerve regeneration.

Studies of nerve repair comparing fibrin glue with suture techniques have produced mixed results. To test the effect of fibrin glue on nerve regeneration without the confounding variables of distraction and/or movement of the anastomosis, nerve repairs were performed with and without fibrin glue on the intratemporal facial nerve of the rat. The location of the nerve transection was the same for control and experimental nerves, but on the experimental side the nerve was repaired with fibrin glue and on the control side of the nerve was reapproximated in the fallopian canal, without glue or sutures. Axon counts distal to the repair revealed no statistically significant difference between the two methods of repair. This result suggests that mechanical obstruction by the fibrin glue between the nerve ends has a negligible effect on nerve regeneration.

Animals↗

PubMed1989

Endoscopic sinus surgery for mucoceles: a viable alternative.

Functional endoscopic surgery affords the potential for dramatically reducing operative morbidity of surgery for paranasal sinus mucoceles by offering a minimally invasive approach under local anesthesia. Following surgery, direct endoscopic visualization of the area enables accurate follow-up. Unlike sinus obliteration, the ability to accurately image the sinus by CT is also preserved. This paper presents our preliminary experience with 18 mucoceles in which endoscopic sinus surgery was attempted. Five patients had preoperative proptosis and diplopia, three had Pott's puffy tumor and five had erosion of the posterior table of the frontal sinus. Fifteen patients were satisfactorily treated endoscopically, two lesions could not be satisfactorily approached and required external surgery, and one patient had persistent disease. No disease recurrence has been noted to date with endoscopic follow-up of up to 42 months.

Adolescent↗