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Biomedical subjects

R H Ossoff

Publications and source records attributed to R H Ossoff.

At least 19 recordsLinked to original sources

An investigation of the potential for laser nerve welding.

Suture repair of a severed peripheral nerve is cumbersome, presents a focus for infection and neuroma formation, and does not always produce adequate stump alignment. An alternative form of repair is laser nerve welding, which is attractive because it does not introduce foreign material into the anastomotic site, it forms a circumferential seal, and it can be performed in difficult-to-reach areas. Laser repair has not been widely accepted both because the effect of laser irradiation on intact nerves is not well documented, and the anastomotic strength of the weld has been inferior to suture repair. In the first part of the present study, rat sciatic nerves were exposed and irradiated with increasing intensities from a Sharplan CO2 and KTP laser to document nerve damage as recorded by decreases in the peak compound action potential. A new technique of laser repair (S-Q weld) was then developed that involved harvesting subcutaneous tissue from the adjacent dermis, wrapping it around the two opposed nerve stumps, and lasering it to the epineurium to effect a weld. The strength of the S-Q weld (6.1 grams) was considerably greater than that produced by laser welding alone. The third phase of the study compared regeneration at 2 months in severed rat sciatic nerves repaired by either microsuture or S-Q weld. Analysis of the compound action potential values indicated that the number of regenerating fibers after laser repair was greater than that after suture repair, although a significant difference could not be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials

Recurrent laryngeal nerve avulsion for treatment of spastic dysphonia.

Treatment of spastic dysphonia by recurrent laryngeal nerve section has resulted in reproducibly good results in the early postoperative period in most patients. However, critical long-term follow-up has shown a high recurrence rate of adductor spasms by the third year after initial nerve section. A patient who developed recurring adductor spasms 1 year after nerve section was reexplored, with identification of neural regrowth into the distal segment of the recurrent laryngeal nerve. The technique of neural avulsion removing the distal nerve up to its insertion into the laryngeal muscles is described. Neural regrowth, which is just one of the possible mechanisms for recurrence of spastic dysphonia, should be prevented by this surgical modification. Twelve patients who have undergone neural avulsion primarily for spastic dysphonia are being followed up without recurrence of symptoms thus far. Although these results appear promising, this short follow-up that averages 1.5 years must be extended to firmly support these concepts.

Female

Neonatal and pediatric microsubglottiscope set.

A microsubglottiscope for infants and children has been developed for microlaryngeal surgery in the glottic and subglottic regions of the larynx. The universal handle allows selection of several sizes of blades to be used according to the patient's anatomic limitations. The tips of these blades have been designed specifically to give exposure to the subglottis and upper trachea under microscopic magnification. A needle adapter for jet ventilation has been included. The authors have used this instrument in young infants and children for diagnosis and for laser resection of subglottic stenosis, hemangioma, and suprastomal granuloma, and have found the exposure to be superior to that obtained with conventional microlaryngoscopes.

Child

Microsubglottoscopy: an expansion of operative microlaryngoscopy.

The development of the adult subglottiscope has facilitated expansion of the indications for operative microlaryngoscopy to include surgery in the subglottic region of the larynx, as well as in the upper cervical trachea. A set of microlaryngeal instruments with an elongated shaft has been developed to support the use of the subglottiscope in the adult patient population. During the 18-month period from January 1, 1988, through June 30, 1989, sixteen adult patients with subglottic or upper cervical tracheal pathology were operated on a total of twenty-three times, using the adult subglottiscope to facilitate exposure and treatment. The patients' pathologic conditions included subglottic stenosis, subglottic granuloma, subglottic extension of laryngeal hemangioma and papilloma, and suprastomal granuloma. Two selected cases are presented to highlight indications for the use of this instrument. We have found the exposure of these subglottic and upper cervical tracheal lesions, using the binocular, microlaryngeal approach facilitated by the adult subglottiscope, to be improved over that obtained with existing microlaryngoscopes or conventional tracheoscopes.

Adult

Advanced microspot microslad for the CO2 laser.

New advances in instrumentation have facilitated the development of a second generation carbon dioxide (CO2) laser microspot micromanipulator. The 710 Acuspot has unique advantages over the previous generation of microspots. The compact design is easier to handle and has attachment points for sterile draping. The unit produces a spot size of 250 microns at a 400-mm focal length and 160 microns at 250 mm; the maximum de-focus is 3.2 mm at all focal lengths. An innovative dichroic mirror allows use of the laser unit's own HeNe laser as the aiming beam, eliminating possible aiming error introduced with a virtual image-aiming system. The dichroic mirror also allows better light transmission, resulting in a brighter field of view. As with first generation microspots, the laser beam path is coincident with the microscope optical path, eliminating parallax; this feature has been especially advantageous in pediatric and otologic cases. Having used this unit for 6 months on more than 50 patients, we now consider the use of a microspot to be our delivery system of choice for most microlaryngeal laser surgical applications.

Adult

Soft-tissue complications of laser surgery for recurrent respiratory papillomatosis.

Twenty-two patients with recurrent respiratory papillomatosis underwent 105 carbon dioxide (CO2) laser microlaryngoscopic and tracheobronchoscopic operations from July 1986 through February 1990. All soft-tissue complications, whether intraoperative or delayed secondary to laser surgery, were retrospectively analyzed. The intraoperative laser-related soft-tissue complication rate was zero. Two of the 22 patients acquired slight unilateral true vocal cord scar tissue and 1 patient developed a small posterior laryngeal web. The delayed soft-tissue complication rate was 13.6%, which compares favorably with published reports of 28.7% and 45%. This low complication rate has resulted from the selection of appropriate CO2 laser emission parameters and the use of the microspot micromanipulator, which help minimize lateral and/or deep thermal damage at the site of laser impact.

Adult

Surgery for benign lesions of the glottis.

This article examines benign lesions of the glottis and adjacent structures commonly encountered in clinical practice. The goals of management are to understand the cause and the characteristics of these lesions and to provide the most conservative management possible. Nonsurgical management is selected, if possible, with surgical intervention reserved for refractory conditions. Traditional cold steel operative techniques as well as carbon dioxide laser techniques are discussed in this article.

Cysts

Endoscopic laser arytenoidectomy revisited.

Arytenoidectomy is currently the most reliable method of treating patients with bilateral vocal cord paralysis. Although both endoscopic and external approaches have been described, the endoscopic laser technique is more desirable because it requires no incision and allows for the immediate assessment of airway size. Eleven patients with bilateral vocal cord paralysis treated by endoscopic laser arytenoidectomy were presented in 1984. At that time, 10 of the 11 patients had been successfully decannulated. Follow-up on that group of patients revealed that 7 of the 10 successfully treated patients remain decannulated with a good airway, although 2 of these patients required a revision procedure to excise a granuloma. One patient failed at 15 months and has failed two subsequent revision operations, and 2 patients have been lost to follow-up. Since 1984, 17 additional patients with bilateral vocal cord paralysis have been treated by the authors using the same endoscopic laser arytenoidectomy technique; all have been successfully managed, with a minimum follow-up of 3 years. The technique of this operation will be reviewed. This study demonstrates the clinical usefulness of endoscopic laser arytenoidectomy in the treatment of bilateral vocal cord paralysis.

Arytenoid Cartilage

Laser application in the tracheobronchial tree.

The use of lasers has greatly expanded our ability to treat diseases of the tracheobronchial tree. We must be aware of the advantages and disadvantages of each particular wavelength. In addition, the specific safety precautions for each laser wavelength must be followed closely.

Bronchial Diseases

Recent advances in thyroid imaging.

Thyroid imaging has evolved from early radionuclide rectilinear thyroid scanning to the recently developed technique of single photon emission computed tomography. At the same time, x-ray fluorescent scanning, ultrasound, computed tomography, magnetic resonance imaging, and positron emission tomography have improved identification of the thyroid gland. The appropriate use and relative roles of these imaging modalities in the investigation of patients with thyroid disease are discussed.

Diagnostic Imaging

Evaluation and treatment of complications of thyroid and parathyroid surgery.

The major complications of thyroid and parathyroid surgery include hemorrhage, respiratory obstruction, hyperthyroid storm, hypoparathyroidism, and laryngeal nerve injury. In this article, the incidence, diagnosis, and treatment of various complications are reviewed, with emphasis on hypoparathyroidism and vocal cord paralysis, either bilateral or unilateral. Thyroplastic phonosurgery and carbon dioxide laser arytenoidectomy, two recent surgical additions to the rehabilitation of vocal cord paralysis, are described in depth.

Aluminum Hydroxide

Laryngotracheal reconstruction with composite nasal septal cartilage grafts.

The composite nasal septal graft has been used successfully by us to reconstruct patients with high tracheal and laryngotracheal stenosis. We have treated ten patients and have been able to decannulate seven of these patients. When these ten cases are added to the six original cases presented in an earlier report (1981), certain conclusions can be drawn. The success or failure of these procedures, which is judged by the ability to decannulate the patient, appears to be related to the extent of the initial injury. We discuss the indications for the composite nasal septal graft and the use of additional treatment, including stents, steroid injections, dilatations, and flaps. In conclusion, the addition of these ten cases to the original six cases of composite nasal septal grafts now provides the opportunity to review indications and contraindications for the use of this graft in the management of advanced laryngotracheal stenosis.

Adult

The use of magnetic resonance imaging with high-resolution CT in the evaluation of facial paralysis.

Magnetic resonance imaging (MRI) has been widely used in the evaluation of suspected acoustic neuroma, but has not received the same attention with respect to facial paralysis. High-resolution computed tomography (HRCT) has been the radiologic test of choice to evaluate the facial nerve. The necessary HRCT projections, slices, and enhancement techniques to visualize each segment have been outlined. We have developed a radiologic protocol that uses MRI in conjunction with HRCT, applying the strengths of each to evaluate the facial nerve. We have evaluated 15 patients and have found that MRI is the better study to evaluate the brain stem/cerebellopontine angle segment of the facial nerve and better evaluates bone-soft tissue interfaces. HRCT is better in the evaluation of the intratemporal segment of the facial nerve and the assessment of the anatomic perspectives of a lesion within the temporal bone. The results are discussed and case reports illustrate the efficacy of this approach.

Adolescent

Laser lingual tonsillectomy.

Diseases of the lingual tonsils are generally overlooked in both clinical practice and medical literature. Infections of the lingual tonsils are usually treated medically, although in patients with symptomatic chronic inflammation or hyperplasia of the lingual tonsils, surgical intervention may be indicated. Eighty-two patients with benign inflammatory problems of the lingual tonsils, who were not improved by medical management, underwent laser lingual tonsillectomy at four different medical centers, between 1984 and 1987. The procedure was tolerated well by all of the patients, with no significant operative complications. Short- and long-term results were satisfactory. Laser surgery is an effective method for the treatment of benign hyperplastic and inflammatory diseases of the lingual tonsils.

Adolescent

Laser safety in otolaryngology--head and neck surgery: anesthetic and educational considerations for laryngeal surgery.

Two investigations concerning anesthetic and educational considerations for laser safety in microlaryngeal carbon dioxide laser surgery have been performed. The first study demonstrated that attendance at a "hands-on" laser surgery course that stressed safety precautions was associated with a reduced rate of laser-related complications in the selected group of otolaryngologists who participated in the course, when compared to another selected group of otolaryngologists who were members of a senior otolaryngology society, and surveyed solely on the basis of their society membership. The second series of studies compared the incendiary characteristics of three endotracheal tubes in various mixtures of oxygen, diluted with either helium or nitrogen. It was determined that the polyvinyl chloride tube should not be used for laser surgery, even when wrapped with reflective, metallic tape. The safest anesthetic gas mixture was found to be 30% oxygen in helium; the addition of 2% halothane did not have an adverse effect, as had been previously reported. Both the Xomed Laser-Shield and Rusch red rubber endotracheal tubes were found to be safe, when used with the laser in the pulsed mode in an atmosphere of 100% oxygen. When the laser was used in the continuous mode, both tubes ignited in an atmosphere of 30% oxygen in helium. These findings challenged the previously reported levels of safety associated with the use of an unwrapped Xomed tube. Based on the results of this investigation, it has been concluded that both the Rusch red rubber tube and the Xomed Laser-Shield tube should be wrapped with reflective, metallic tape, when used for cases of microlaryngeal surgery with the carbon dioxide laser.

Anesthesia

The advantages of laser treatment of tumors of the larynx.

The carbon dioxide (CO2) laser is safe and efficacious when used in conjunction with endoscopic excision of selected premalignant and malignant tumors of the larynx. Cure rates parallel those obtained with traditional surgical instruments. Advantages of laser excision of early glottic carcinomas include greater accuracy in establishing the true extent of the disease, minimal morbidity, and cost effectiveness.

Endoscopy