Cancer Advisory Board.

The article "Reagan seeks expansion of Soviet ties" by R. Jeffrey Smith (News and Comment, 13 July, p. 145) erroneously stated that the U.S. Senate had passed a resolution calling for a U.S.-Soviet summit "without preconditions or assurances of success." Shortly before midnight on 19 June, the resolution was amended to call for a summit at "the earliest practical time following thorough preparation." It was approved in this form.

Laser surgery in otolaryngology: interaction of CO2 laser and soft tissue.

The sequence of histological change induced by CO2 laser irradiation was discussed in terms of two factors: the physiomechanical factor and the physiochemical factor. At sufficiently high heat energy levels, the immediate findings are characterized by crater formation resulting from rapid vaporization of the water and ejection of the solid component. In the immediate vicinity of the crater edge, the maximum tissue temperature rise is 65 degrees C above the 32 degrees C ambient tissue temperature and it decreases to the primary tissue temperature within a distance of 2 mm. The healing process of CO2 laser induced lesions proceeds with minimal delay. The lymphatic and vascular channels are occluded in the marginal area of coagulation resulting in a marked hemostatic effect. This sealing effect increases the margin of safety in preventing possible dissemination of tumor cells. By selecting the appropriate power, time, and focus cone angle, precise destruction of preselected areas of tissue can be achieved with an extraordinary hemostatic effect without damaging the underlying tissue. These advantages are especially helpful in function-preserving surgery.

Laryngeal carcinoma: transoral treatment utilizing the CO2 laser.

The CO2 laser has been found to be a useful adjunct in our efforts to treat laryngeal carcinoma. Utilized endoscopically, it has been of help in establishing the proper staging, in diagnosing recurrence after radiation therapy, in reestablishing airways blocked with tumor, in debulking tumor mass prior to radiation and/or chemotherapy, and as a primary mode of excisional therapy, all accomplished with minimal morbidity. Most patients may return home the first postoperative day, eating, with serviceable voice, and requiring no tracheotomy or analgesics, all of which provide a significant cost benefit.

The anatomic limitations of CO2 laser cordectomy.

The anatomical limitations of CO2 laser cordectomy in an experimental setting with maximal exposure are presented. The major limitation is the thyroid cartilage. This is reached in the area of anterior commissure tendon by removal of only 2 to 3 mm of soft tissue. Most posteriorly in the larynx, the distance to the thyroid cartilage becomes progressively greater, being 5.3 mm at mid-cord and 9.0 mm at the anterior end of the vocal process of the arytenoid. The inferior limitation is the cricothyroid membrane. Anteriorly this is avoided by not extending laser excision more inferiorly than 5 mm's. Posterolaterally, the limitation is the para-arytenoid musculature. Excisional biopsy or staging with the laser must be within the framework of these limitations.

Transoral management of localized carcinoma of the oral cavity using the CO2 laser.

Since 1972 we have been cautiously exploring the use of CO2 laser in the management of carefully selected cases of localized carcinoma of the oral cavity. At the present time our experience is based on the treatment of 57 patients with cancer of the oral cavity. The CO2 laser has been found to be an indispensable tool in the transoral management of T1 carcinomas, multiple superficial carcinoma, extensive leukoplakia and verrucous carcinoma. The laser allows precise excision of the lesion and involved mucosa and provides and excellent specimen for histologic verification of the margins. The morbidity of laser excision is minimal, so that a tracheotomy is not needed and patients can almost always be discharged on the following day. (Follow-up data on those patients at risk for 30 months indicate excellent control rates).

Management of choanal atresia with the carbon dioxide laser.

Congenital choanal atresia frequently demands immediate recognition in the newborn, and provision of a nasal airway as soon as possible. A variety of techniques are available to correct this problem, but none is entirely satisfactory. Transpalatal procedures are associated with significant morbidity in the newborn, and transnasal microsurgical procedures are less predictable when a thick bony plate is present in the choanal obstruction. Transnasal resection with the CO2 laser has been carried out in seven patients (ten sides), whose ages ranged from 16 hours to 14 years. From this early experience, it appears that the procedure is entirely feasible and convenient. It seems to have significant advantages over conventional microsurgical techniques. Eight out of ten choanae have remained patent for four months or more. A lumen keeper is needed during the immediate postoperative period for at least two to three weeks. The procedure is associated with minimal morbidity.

Minimally Invasive Direct Access Surgical Technology - MIDAST(TM).

The minimally invasive direct access surgical technology (MIDAST) has grown out of previous experience applied in otolaryngology and endoscopic microsurgery. From the time of Ambroise Pare and for centuries surgeons have made large incisions to gain adequate access for manipulation with large, straight, bulky instruments and achieved adequate illumination by the sun and later by artificial lighting.

Minimal and direct access aortoiliac reconstructive surgery.

Despite improvements in surgical practice and postoperative care, the large transperitoneal approaches used in elective aortic reconstructive surgery are still associated with a relatively high perioperative morbidity and mortality rate, even in patients who are good risks for undergoing aortic surgery.,,2This perioperative morbidity is partly caused by major surgical trauma.

Minimal access ureterolithotomy.

A new minimally invasive ureterolithotomy is herein described which utilizes a 3 cm long skin incision. Surgery is performed with the aid of a newly developed bivalve retractor endoscope (Jakoscope) which provides excellent illumination with built-in double fiberoptic light cables and high intensity light source. The new surgical technique can be utilized in the rare cases of ureteral stone when other standard modalities may not work or when the patient demands definitive rapid treatment, and cannot be followed postoperatively.

Retractorscopic nephrectomy: initial report.

The authors describe a newly developed minimal access method for nephrectomy. The mini approach-a 5 cm skin incision-can be performed with a special retractorscope, which is an open lumen "scope" with fiberoptic light system.

The effects of ultra-violet laser radiation on cancer.

A group of mice implanted with squamous cell carcinoma (CA1025) and melanoma (B16) were irradiated with a cw krypton laser using 3374A (total dosage 346 j/cm2, and 660 j/cm2), and 3507A (total dosage 367 j/cm2), and a pulse N2 laser 3371a (total dosage 471 j/cm2, 660 j/cm2, and 165 j/cm2). In all groups, tumorous mice were used as controls. Regression of tumors was observed at wavelengths of 3374A and 3371A (total dosage 471 j/cm2 and 660 j/cm2). No regression was observed at 3507A. The regression in some cases was very impressive. The preliminary work on N2 laser irradiation of basal cell carcinoma (in human beings) and of BEL 7404 liver carcinoma cells in vitro and irradiation of one patient with an N2 laser performed in China will also be reported.