PubMed Health⌕ Search

Biomedical subjects

V G Lawson

Publications and source records attributed to V G Lawson.

At least 19 recordsLinked to original sources
PubMed1990

Trans oral approach to the nasopharynx and clivus using the Le Fort I osteotomy with midpalatal split.

The Le Fort I level osteotomy is a procedure well known to oral and maxillofacial surgeons, who routinely use it to correct midfacial skeletal deformities and alter the dental occlusion. This osteotomy can also be used as a maxillotomy for access to more superiorly and posteriorly situated structures. The downfracture technique provides the surgeon with a safe approach that allows visualization of the maxillary sinuses, nasal cavity, nasopharynx, base of the skull and upper cervical spine. This approach can also be combined with a midline lip split, mandibulotomy and glossotomy to give access to retropharyngeal structures. By modifying the combined Le Fort I and transmandibular approach utilizing a midline split of the hard and soft palate, the access to the clivus can be improved considerably. The clinical applications of these combined procedures in the treatment of basilar invagination and tumors of the nasopharynx are discussed.

Adolescent↗
PubMed1988

Comparison of glottic areas measured by acoustic reflections vs. computerized tomography.

We compared measurements of glottic area obtained by acoustic reflection technique with anatomically equivalent area measured from computerized tomographic (CT) scans of the neck in 11 subjects with glottic pathology. Both measurements were performed in the supine position during tidal breathing at functional residual capacity. We found excellent agreement in glottic areas obtained by both methods: the mean (+/- SD) values were 1.8 +/- 0.8 cm2 for the acoustic method and 1.7 +/- 0.9 cm2 for the CT method. Linear regression analysis revealed the following relationship between the area measured by acoustic technique (AAC) and that measured by CT (ACT): AAC = 0.81.ACT + 0.36. There was a significant correlation between the two measurements of glottic area (r = 0.95, P less than 0.0001). We conclude that the acoustic reflection technique may be used reliably in clinical and physiological studies concerned with glottic geometry.

Acoustics↗
PubMed1987

Airway area by acoustic response measurements and computerized tomography.

In order to determine more precisely the accuracy with which the acoustic reflection technique (ART) can infer airway area during spontaneous breathing, we compared acoustic measurements of airway area with equivalent areas measured from computerized tomographic (CT) scans of the neck and chest in 7 patients (mean age, 54 yr; range, 33 to 69 yr) with a history of upper airway abnormalities. At the time of the study, all patients were clinically stable and had no recurrent nerve palsy. Measurements of airway area by ART and CT were performed in the supine posture while patients breathed quietly at FRC. We found that there was considerable intersubject variability in area-distance functions determined by acoustic reflections. None of the subjects had a flat tracheal plateau. Once the acoustic and CT data were aligned, we compared cross-sectional areas at various distances from the glottis. Comparison points were separated by 1 cm, and as many as 13 different CT sections were used in some subjects. Mean values for all data points (n = 83) were 2.45 +/- SD = 0.69 cm2 and 2.56 +/- SD = 0.82 cm2 for the acoustic and CT methods, respectively, Z = 0.93; p greater than 0.05. Linear regression analysis revealed a correlation coefficient (r) of 0.92; p less than 0.0001. On the basis of these findings, we conclude that the acoustic reflection technique may be used reliably for clinical and physiologic studies of the upper airways in humans.

Acoustics↗
PubMed1986

Pectoralis major muscle flap with amnion in oral cavity reconstruction.

The pectoralis major myocutaneous flap provides an excellent method for reconstruction of oral cavity defects. This flap has been used since 1978. However, the flap is not without problems. The major problem that has been seen is necrosis of the cutaneous and subcutaneous aspects of the flap. However, in all such instances the muscular portion of the flap survived. This complication was found to occur more commonly in the elderly, diabetics, patients with peripheral vascular disease and patients with excessive adipose or breast tissue superimposed between the cutaneous and muscular components of the flap. In this study the technique of oral cavity reconstruction in the high risk patient group has been modified to avoid using the skin component of the pectoralis major myocutaneous flap. Instead, pectoralis major muscle covered with amnion is used for reconstructive purposes with rapid healing and with very satisfactory functional and cosmetic results.

Amnion↗
PubMed1986

Effect of CO2 concentrations on acoustic inferences of airway area.

To determine the effect of gas composition on the accuracy of measurements of airway area and distance using an acoustic reflection technique, we employed glass-tube models to simulate pharyngeal (Phar-model), laryngeal (Lar-model), and tracheal (Trach-model) regions of upper and central airways. We made repeated measurements of area-distance functions using gas mixtures containing 0, 2, 4, 6, 8, and 10% CO2, 80% He, and balance O2. The actual area of the model was calculated from the roentgenographic data and compared favorably with an area measured by acoustic reflections using a gas mixture containing 0% CO2. With the different gas mixtures, calculated area was overestimated only at the highest levels of CO2, with Phar-model area increasing from (mean +/- SD) 4.66 +/- 0.03 cm2 measured with 0% CO2 to 4.93 +/- 0.05 cm2 (P less than 0.05) measured with CO2 concentration of 10%. To assess the effect of CO2 concentration on measurements of distance, we isolated two discrete points located in the Phar-model and Lar-model regions. When measurements were performed using 10% CO2 mixture, Phar-model point was shifted by 1.02 +/- 0.03 cm and Lar-model point was shifted by 2.16 +/- 0.09 cm away from the microphone compared with their axial position determined, using 0% CO2 mixture (P less than 0.05). Differences in area-distance calculations at the higher levels of CO2 did not exceed the within-run variability of the technique (10 +/- 4%). We conclude that CO2 absorbers are not required during measurements of airway area by acoustic reflections, provided CO2 concentration does not exceed 10%.

Acoustics↗
PubMed1986

Fishing for foreign bodies.

A guide to the radiological detection of fish bones for the sporting physician is presented. By radiologically examining fish bones superimposed on the neck, it was found that most bones are detectable, thus lending support to the use of plain neck films in screening for impacted fish bones.

Animals↗
PubMed1985

Oral cavity reconstruction using pectoralis major muscle and amnion.

The pectoralis major myocutaneous flap has become the mainstay of major oral cavity reconstruction. The flap provides excellent soft-tissue bulk and cavity or surface lining for major defects. There is a high rate of primary take. However, the flap has some deficiencies. A group of patients were identified that are likely to have less than ideal results with the pectoralis major myocutaneous flap technique. In these cases, the flap has been modified and amnion has been added. Initial results indicate enhancement of reconstruction with the modified technique.

Aged↗
PubMed1984

Reconstruction of the pinna using pre-auricular flaps.

The pre-auricular skin reservoir provides an excellent source of full thickness skin for reconstruction of defects of the pinna. Pre-auricular flaps may be based superiorly or inferiorly. The skin texture and color match is ideal for pinna reconstruction.

Carcinoma, Squamous Cell↗
PubMed1983

The management of airway involvement in thyroid tumors.

I have reviewed 100 consecutive cases of surgically managed thyroid disease. Of those, 35% had evidence of airway involvement. The airway involvement can be classified in the following fashion: compression alone, displacement with compression, displacement without compression, infiltration of the airway with or without compression or displacement, and neurogenic dysfunction of the airway. Definitive management of these cases involved resection of the thyroid gland with decompression of the airway in compressive and/or displacement disease, and en bloc composite resection of the thyroid and involved airway in infiltrative disease. In all cases, with the exception of those involving anaplastic carcinoma, restoration of normal airway function and control of disease was possible.

Airway Obstruction↗
PubMed1983

Repair of facial defects with advancement-rotation flaps.

The advancement-rotation facial flap is very useful for repair of middle one-third facial defects of moderate size, resulting from deep resection of neoplastic disease. Flaps containing skin and subcutaneous tissue, or flaps containing skin, subcutaneous tissue, and neuromuscular bundles are employed. An extensive facial release is necessary in order to develop flaps to close large defects in the order of 5 cm. This is a superior, one-stage method for repair of large defects, particularly in elderly patients. The technique can produce excellent cosmetic and functional results.

Aged↗
PubMed1982

Wegener's granulomatosis and the respiratory system.

Wegener's granulomatosis is a disease characterized by necrotizing vasculitis of the upper and lower respiratory tracts, necrotizing glomerulonephritis, and varying degrees of disseminated small vessel vasculitis. Patients can present to an otolaryngologist head and neck surgeon with ear, nose, throat, lung, orbit, salivary gland, or cutaneous lesions. The disease is variable in its presentation and progression. Tissue biopsies may be non-diagnostic even in the presence of active disease. Although the disease was rapidly fatal as recently at 1970, it can now be effectively treated. This paper reviews the diagnosis and management of Wegener's granulomatosis at a major university hospital between 1965 and 1979. during this period there was a significant evolution of treatment methods.

Adult↗
PubMed1979

Management of advanced and recurrent facial carcinoma.

I report five cases of advanced and recurrent facial carcinoma to illustrate the extent to which such disease can develop and yet be compatible with life. Radical treatment approaches are used so as to maximize the chances for tumor ablation and survival as well as for restoration of function and cosmetics.

Aged↗
PubMed1979

Unusual parapharyngeal lesions.

Six cases of unusual parapharyngeal lesions are presented in detail along with discussions of the anatomy, pathology, clinical aspects, and treatment methods of lesions in the parapharyngeal space. Newer techniques of CT scanning and selective embolization are discussed as they apply to management of such lesions. A plasmalymphocytic tumor with amyloidosis is described. The authors believe that such a lesion has not been reported previously in the parapharyngeal space.

Adenoma, Pleomorphic↗
PubMed1979

Thyroid carcinoma presenting as a tracheal tumor. Case report and literature review with reflections on pathogenesis.

Ectopic thyroid tissue within the submucosa of the trachea is a rare cause of upper airway obstruction. Most case reports in the literature record examples of intratracheal goiter with only occasional reports of neoplasms arising from such thyroid rests. This report describes a young female patient with a malignant tumor, thought to be primary in the trachea, treated first by radiotherapy and eventually successfully surgically excised. The surgical resection required total thyroidectomy with partial laryngectomy and major tracheal resection, and provided an excellent functional result. The clinical history, laboratory findings and histologic sections strongly suggest that this tumor arose within the tracheal submucosa from ectopic thyroid tissue. In a series of 250 serially sectioned larynges, such ectopic thyroid tissue has been identified in only two patients.

Adenocarcinoma↗
PubMed1978

Management of the twisted nose.

This presentation discusses the development, pathophysiology, and method of management of the twisted nose. The surgical logistics of staging, open and closed approach, anesthetic method, and reconstructive planning are considered in detail.

Humans↗
PubMed1978

Carcinoma of the lip--a case presentation.

An unusually advanced case of squamous cell carcinoma of the lip is presented. Case management involved the use of a radiosensitizing agent, radiotherapy, surgical resection, and reconstruction. Two years later the patient is free of disease.

Carcinoma, Squamous Cell↗