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Biomedical subjects

G Lawson

Publications and source records attributed to G Lawson.

At least 55 records · Page 3Linked to original sources
PubMed1996

Subtotal carbon dioxide laser arytenoidectomy by endoscopic approach for treatment of bilateral cord immobility in adduction.

Subtotal carbon dioxide (CO2) laser arytenoidectomy for endoscopic treatment of bilateral immobility of the vocal folds in adduction is a variant of total arytenoidectomy. The principal modification involves preservation of a thin posterior shell providing good postoperative fixation of the arytenoid region. The risk of aspiration is thus averted and collapse of arytenoid mucosa into the larynx during inspiration is prevented. The risk of synechia with the posterior commissure is avoided. The CO2 laser is operated at a working distance of 400 mm with a continuous 7-W beam in superpulse mode. Operation time is thus reduced to approximately half an hour and the risk of postoperative edema is reduced. Tracheotomy is not necessary. Forty-one patients, including 16 men and 25 women, were treated by this technique between 1985 and 1994. Their mean age was 55 +/- 17 years, ranging from 11 to 83 years. Follow-up ranged from 1 month to 111 months (9 years 3 months), with a mean of 56 +/- 29 months (4 years 8 months). The mean peak forced expiratory flow-peak inspiratory flow ratio (normal = 1), which permits a measurement of respiratory quality, is improved from 3.7 +/- 1.4 preoperatively to 1.6 +/- 0.5 postoperatively (p<.001). Postoperative voice measurements show a mean vocal intensity of 61 +/- 3 dB hearing level, a mean maximum phonation time of 8 +/- 4 seconds, and a mean phonation quotient of 397 +/- 150 mL/s. As for vocal quality, 38% of the patients now have a near-normal voice according to our high-resolution frequency analysis, and all of the patients retained satisfactory voice quality.

Adult↗
PubMed1995

Treatment of vocal fold immobility by glutaraldehyde-cross-linked collagen injection: long-term results.

Fifty-three cases of unilateral vocal fold immobility treated by glutaraldehyde-cross-linked (GAX) collagen over a 6-year period with a mean follow-up of 4.5 years were reviewed for assessment of the immediate and long-term effects on phonation. The mean amount injected was 1.47 mL. No long-term local or systemic reaction to the collagen was seen. The median preoperative maximum phonation time (MPT) was 7.5 seconds, the median immediate postoperative MPT 12 seconds, and the median long-term postoperative MPT 11 seconds. The median preoperative phonatory quotient (PQ) was 564 mL/s. The median immediate postoperative PQ was 320 mL/s, whereas the median long-term postoperative PQ was 385 mL/s. The quantitative improvement in the voice as measured by the PQ was thus 67% for the short range and 49% for the long range. The decline in the results over time was 20.3%. Vocal frequency analysis showed that the fundamental frequency and harmonics returned and were maintained in the long term for more than 80% of the patients with the help of speech therapy. This relative stability is explained by the findings of previous histological work. The fact that collagen, unlike Teflon, does not cause an inflammatory reaction and the partial maintenance of the improvement achieved, which is to be compared with the instability of the effects produced by resorbable substances, make it the "least objectionable" injectable for the treatment of unilateral glottic fold immobility. One must overcompensate 20% to 30%, given the results of the long-term stability studies.

Collagen↗
PubMed1995

CO2 laser and Gianturco stent for endoscopic treatment of tracheal stenosis.

The self-expandable Gianturco stent was used in eleven cases of tracheal stenosis treated from September 92 to July 94. The stent is placed through a 9 mm outside diameter bronchoscope under optical control after cross-section and dilation of the stenosis with the CO2 laser according to the Shapshay technique. The follow-up varies from 3 to 22 months with a mean of 12 +/- 6 months. Pulmonary function tests (PFTs) show a mean improvement of the PEF (peak expiratory flow). Complications have been corrected in three patients with a second endoscopic procedure: the first case for malposition, the second for granuloma at the superior end of the prosthesis, and the third for the development of a mucous membrane webbing between the two loops of the stent. Owing to the lack of long-term follow-up, we reserve this technique for the treatment of severe tracheal stenosis with cartilage impairment in patients contraindicated when external reconstructive surgery is contraindicated.

Aged↗
PubMed1995

[Granular cell tumor localized in the glottis in children. Apropos of a case].

We report the first case of adult granular cell tumor form localized in the glottis in a 8 year-old girl. The first symptom was a chronic dysphonia. Examination with rigid optic demonstrated an irregular yellow hypertrophic lesion in the posterior third of the left vocal fold. The lesion was removed by CO2 laser micro-spot under general anesthesia. There has been no recurrence after 15 months of follow-up and the postoperative voice quality is satisfactory regarded both objectively as subjectively. Granular cell tumors are rare. The histogenesis is still badly known. Enzymological and electron microscopy studies seem to indicate a nervous origin (Schwann cells). Treatment is surgical. Wide local excision is the general rule for limited lesions with easy access. When bigger lesions are present in more vital structures such as trachea or oesophagus, surgery has to be more cautious.

Child↗
PubMed1994

Treatment of lingual tonsillitis by transoral CO2 laser endoscopy.

The authors report on their clinical experiences concerning 100 cases of chronic lingual tonsillitis. The surgical treatment employed was endoscopic vaporization of affected tissues with the CO2 laser. Prior to surgical intervention, predisposing conditions such as allergy, rhinosinusitis, and gastroesophageal reflux were identified and treated. The surgical technique consisted of progressive vaporization of the lymphoid tissue at the base of the tongue until the lingual fascia was reached. A slightly defocused (700 mm) continuous 10-15 W laser beam was used at a working distance of 400 mm. Following surgery, no dyspnea was observed secondary to epiglottic edema and only one patient required postoperative hemostasis. Symptoms related to tonsil or tongue inflammation were eliminated or alleviated in 87 patients, remained unchanged in 12 patients and were worse in 1 patient.

Chronic Disease↗
PubMed1993

[Recurrent respiratory distress and idiopathic subglottic stenosis: what treatment?].

BACKGROUND: Idiopathic subglottic stenosis is a rare cause of acute respiratory distress, that is difficult to treat (corticosteroids, tracheotomy). CASE REPORT: A nine-year-old boy presented with acute respiratory distress due to tracheal stenosis. The symptoms recurred after the endotracheal inflammatory membranes had been removed with forceps, despite 6-months of degressive corticotherapy. Absence of other causes of tracheal stenosis and biopsies led to diagnosis of idiopathic subglottic stenosis. The patient was treated by CO2 laser followed by degressive corticotherapy. The respiratory distress recurred within 3 months of discontinuing corticosteroids, requiring two further CO2 laser treatments. The patient became corticodependent. CONCLUSIONS: CO2 laser is an effective, wise alternative treatment of acute respiratory distress due to idiopathic subglottic stenosis that can be repeated if necessary.

Acute Disease↗
PubMed1992

Carcinoma of the larynx. Surgery: general aspects.

A necessary and adequate selection of operations capable of meeting all the indications involved by partial surgery, is required. We suggest such a selection inspired on that of 1983. Partial laryngectomies for glottic carcinoma: CO2-laser endoscopic cordectomy, fronto-lateral partial laryngectomy (LEROUX-ROBERT), hemiglottectomy (GUERRIER), anterior partial laryngectomy with epiglottoplasty (TUCKER), subtotal laryngectomy with cricohyoidoepiglottopexy (MAJER-PIQUET). Partial laryngectomies for supraglottic carcinoma: horizontal supraglottic laryngectomy (anterior approach), CO2-laser endoscopic epiglottectomy, lateral supraglottic pharyngo-laryngectomy (ALONSO), subtotal laryngectomy with cricohyoidopexy (LABAYLE). Total laryngectomy As from the early eighties onwards, the great progress in vocal rehabilitation following laryngectomy has certainly been the development of phonatory prosthesis.

Humans↗
PubMed1991

[Tumors of the submaxillary gland].

The tumors of the submaxillary gland are rare. The authors are reviewing 23 cases gathered from three Departments over ten years. The tumors of the submaxillary gland are malignant in as many as 50% of all cases! When the lesion is benign, pleiomorphic adenoma is the most frequent possibility. The authors emphasize the necessity of early and complete surgical treatment, requiring at least total submaxillectomy in case of benign tumor. Cervical mode dissection will be considered if the tumor is malignant.

Adenoma, Pleomorphic↗
PubMed1990

Pseudointimal thrombogenicity changes in small arterial grafts.

Prosthetic grafts are rapidly covered by blood proteins after implantation. Cellular ingrowth and accumulation of interstitial proteins such as collagen complete the development of graft pseudointima. To investigate the effect of these changes on graft platelet reactivity, indium 111-labeled platelet accumulation on two grafts of differing porosity and thrombogenicity (polytetrafluoroethylene [PTFE] and Dacron) was measured 1, 7, and 21 days after graft implantation in canine carotid arteries. Pseudointima structure, weight, and collagen content were also determined at each measurement interval. In addition, platelet accumulation on carotid autografts and dissected carotid arteries was determined for comparison. Platelet accumulation on all grafts and arteries diminished significantly (p less than 0.05) between 1 and 7 days. Platelet accumulation on autografts and dissected arteries decreased further between 7 and 21 days and approached baseline. In contrast, platelet accumulation on Dacron grafts increased significantly (p less than 0.05) between 7 and 21 days to levels above those measured at 1 day, whereas platelet accumulation in PTFE grafts increased minimally and remained significantly below 1-day levels. A thick pseudointima that contained significant amounts of collagen developed in Dacron grafts during this time period, and a thin, incomplete pseudointima containing minimal collagen covered PTFE grafts. These differences in pseudointimal platelet reactivity and composition were associated with decreased patency of Dacron grafts (78%) compared to PTFE grafts (89%).

Animals↗
PubMed1990

Repair of coronal and subcoronal hypospadias: an 8-year retrospective study.

Twenty-three patients undergoing treatment for coronal and subcoronal hypospadias over an 8-year period were reviewed. A ventral skin tube inlay graft was used in all cases, and a comparison made between Nesbitt's button hole technique and three other procedures used for ventral skin cover. The button hole procedure was associated with fewer fistulae and provided acceptable cosmesis.

Humans↗
PubMed1988

[Human African trypanosomiasis in the north of Benin. A preliminary serologic survey].

Atacora Province has been for a long time a focus of human trypanosomiasis in the People's Republic of Benin. If the prevalence has appreciably decreased in the 1960s on account of the experienced methods of tracking down and a sustained supervision, it is easy to establish and to fear today the waking and even the extension of the historic focus formerly called "Foyer Atacora". Since 1974, new patients in second period of the infection are tracked down each year; they particularly come from the localities of Tanguieta and Materi. This suggests that sleeping sickness still persists in the North Country; that is the reason why it appears interesting to evaluate the present state of African human trypanosomiasis in this region of Benin; this appraisal has been tried from a clinic and serologic survey during May 1986 in the the population of four localities of this province: N'Dahonta, Porga Forêt, Porga Village and Dassari.

Adolescent↗