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Biomedical subjects

R H Ossoff

Publications and source records attributed to R H Ossoff.

At least 55 records · Page 3Linked to original sources
PubMed1994

Bacteria identification of otitis media with fluorescence spectroscopy.

We have investigated the fluorescence profiles of four common pathogens: S. pneumoniae, S. aureus, M. catarrhalis, and H. influenzae. The steady-state auto fluorescence spectra of bacteria are measured as a function of the incident light from 200 to 700 nm. The spectra for each bacterium are combined into a fluorescence profile or fluorescence finger print. Each bacterium produces a unique in vitro fluorescence profile when measured in a saline suspension. The profiles are reproducible. Suspensions of a bacterial strain, where the identification is not known, can be correctly matched to a small library of previously measured fluorescence profiles using a linear least-squares fitting algorithm. In addition, we have measured the fluorescence and absorption spectrum of the tympanic membrane removed from a chinchilla. The optical properties of the tympanic membrane and the least-squares identification process form precept for a non-invasive, fluorescence based bacterial diagnosis technique to be used in otitis media.

Algorithms↗
PubMed1994

Clinical applications of lasers in otolaryngology--head and neck surgery.

The use of lasers in otolaryngology--head and neck surgery is described from the invention of the laser in 1960, through the current uses of the laser, and concludes with a summary for the future directions of laser surgery. The various lasers, including the argon, the KTP, and the carbon dioxide lasers used in otolaryngology, are briefly described. The applications of lasers in the larynx, sinuses, and the ear are separately covered, as well as pediatric otolaryngology. In addition to a brief description of the procedure, the complications and limitations are given. Anesthetic considerations are also covered.

Head and Neck Neoplasms↗
PubMed1994

Evaluation and treatment of the unilateral paralyzed vocal fold.

The evaluation and treatment of patients with unilateral vocal fold paralysis have evolved as improvements in objective measurements of phonatory function and new modalities for treatment have developed. A thorough history, physical examination, subjective voice evaluation, objective voice analysis, and electromyography are used to make a diagnosis, determine the cause, and plan treatment. The goal of treatment of the patient with a unilateral vocal fold paralysis is to restore normal phonatory function without aspiration. Multiple modalities have developed to allow for restoration of nearly normal phonatory function, and these include voice therapy alone or in combination with injection medialization, laryngoplastic phonosurgery, or laryngeal reinnervation. Otolaryngologists should be familiar with the incidence, cause, evaluation, and state-of-the-art treatment of unilateral vocal fold paralysis of optimize patient care and avoid suboptimal results often seen with antiquated or inappropriate treatment.

Humans↗
PubMed1994

Noninvasive optical diagnosis of bacteria causing otitis media.

Currently, the identification of the bacteria responsible for acute otitis media requires a painful invasive procedure: tympanocentesis. To develop a rapid and noninvasive technique for bacterial diagnosis, the fluorescence profiles of four common pathogens and the optical characteristics of the tympanic membrane have been investigated. Each bacterium produces a unique in vitro fluorescence profile when measured in a saline suspension. Also, spectrally resolved transmission measurements from the chinchilla tympanic membrane demonstrate an optical window that will transmit sufficient light for in vivo measurement of the fluorescence profiles. Thus, we have established the precept for a fluorescence-based bacterial diagnosis technique to be used in otitis media. This paper presents the theory, optical data, and a discussion of the device engineering involved in the technique.

Animals↗
PubMed1994

Computer-assisted surgical techniques using the Vanderbilt Free Electron Laser.

The Vanderbilt Free Electron Laser (FEL) is capable of lasing between 2.0 and 8.0 microns with a high peak intensity pulsed structure. The FEL is used to investigate potential applications in otolaryngology. Charring of temporal bones and thermal stress patterns in Plexiglas indicate thermal buildup at 20 and 10 Hz repetition rates of the laser. Also, transient temperature changes measured with thermocouples in a gelatin model reveal that significant heat production occurs at these laser repetition rates. To utilize the fastest laser repetition rates and maintain minimal lateral thermal damage, a computer-controlled scanning system was devised. The authors have also used the computer control with the carbon dioxide laser and experienced improved ablation.

Animals↗
PubMed1994

Computer-assisted surgical techniques: a vision for the future of otolaryngology-head and neck surgery.

Our specialty relies increasingly on technologic advancements and increased knowledge of pathophysiology at the cellular and molecular level; these trends will continue. The consequences in the laryngologic, otologic, and rhinologic surgery are presented. Envision the surgeon positioned at a computer workstation to perform surgery. Following endoscopy and the placement of the microlaryngoscope, the only contact he or she will have with the patient is through robotic "hands" on the end of thin rods. These hands thread through the laryngoscope and hold tissue without any tremor. Multiple-wavelength lasers are available, each tuned to optimally incise particular tissue types. The laser beam will be delivered under computer control with active feed-back systems involving ultrasonic imaging, infrared thermography, and photoacoustic monitoring. Similar visions are presented in otology and rhinology with microinstrumentation and virtual reality.

Acoustics↗
PubMed1993

Carbon dioxide laser serial microtrapdoor flap excision of subglottic stenosis.

The recent development of microspot micromanipulators for the carbon dioxide laser with 250-microns spot sizes has greatly facilitated the extension of endolaryngeal procedures to children and neonates. It is possible to accurately develop microtrapdoor flaps within the limited exposures in the pediatric subglottis. We have used serial microtrapdoor flaps in the excision of subglottic scar tissue in eight children. In five children, the stenosis was improved with relief of stridor. In three children, the flaps were used as an adjunct to laryngotracheoplasty. The surgical techniques of this procedure are detailed in this report.

Child↗
PubMed1993

Sub ablation effects of the KTP laser on wound healing.

The KTP laser (wavelength 532 nm) was used in a sub ablative format to determine the effect of low energy density irradiation on the normal healing by primary intention of scalpel skin incisions in rats. Two longitudinal lased strips were created by a 1 cm diameter defocused beam on the shaved, cleaned dorsal epidermis of 32 Sprague-Dawley rates; one strip was produced with a 2.0 W beam (54 J, or 18 J/cm2 total dose), and the other with a 3.5 W beam (94.5 J or 31.5 J/cm2, total dose). Scalpel incisions were made longitudinally within the irradiated zones, using contra lateral scalpel incisions on unirradiated skin as controls. Tensiometric analysis of wound strength was performed at 3, 7, 14, and 23 days following surgery. The data from fresh tissue tensiometry indicate that KTP laser irradiation of skin incisions results in a lower tensile strength for the wound at 7 and 14 days. The decrease in tensile strength is proportional to the total energy density of the exposure. At day 3 and 23, the tensile strength of the wound was independent of the sub ablative laser exposure. The results are in general agreement with studies of the healing process of laser incisions and may help us to understand the details of the healing process from laser incisions.

Animals↗
PubMed1993

Difficulties in endoscopic removal of Teflon granulomas of the vocal fold.

The difficulties in treating granulomas resulting from Teflon injection into the vocal fold are underreported in the literature. We have reviewed our experience with nine patients undergoing 27 procedures for Teflon granuloma. Two patients required tracheotomy before undergoing endoscopic granuloma removal because of airway compromise, and a third required urgent tracheotomy following endoscopy. One of the patients requiring elective tracheotomy had a granuloma that extended across the midline to the contralateral arytenoid, causing its fixation. Arytenoidectomy was required for decannulation in this patient. In all but one patient the granuloma nearly completely replaced the thyroarytenoid muscle. This extensive involvement often precludes the adequate excision of the granuloma in a single procedure; however, the microflap technique allows mucosal preservation to facilitate future procedures. In some cases the granuloma destroys large amounts of mucosa, and a microflap cannot be elevated and saved. The difficulties of excision are related to the near-total replacement of the thyroarytenoid muscle by granuloma. This paper will help the otolaryngologist--head and neck surgeon understand this destructive process and the resulting difficulties in surgical rehabilitation.

Adult↗
PubMed1993

Silastic medialization and arytenoid adduction: the Vanderbilt experience. A review of 116 phonosurgical procedures.

From April 1987 to April 1992, 116 phonosurgical procedures were performed to treat glottal incompetence. The initial numbers of these surgical procedures included the following: 29 primary Silastic medializations, 3 primary Silastic medializations with arytenoid adduction, 53 secondary Silastic medializations, 4 secondary Silastic medializations with arytenoid adduction, and 11 bilateral Silastic medializations. These procedures are useful in treating unilateral true vocal cord paralysis, scarring, bowing, or paresis, as well as bilateral true vocal cord bowing. Of the initial 100 patients, 16 later underwent a revision with either a larger implant's being placed or an arytenoid adduction. Primary Silastic medialization is the placement of an implant under general anesthesia in the same surgical setting in which laryngeal innervation is sacrificed. Secondary Silastic medialization is the placement of an implant under local anesthesia for a preexistent vocal cord malfunction. In either case, overall voice results for unilateral paralysis are very good. Primary Silastic medialization significantly decreases the postoperative rehabilitation period in skull base patients because of the immediate postoperative glottal competence and decreased use of perioperative tracheotomy. Bilateral implants yielded good results in 6 patients with presbylaryngis, but 6 other patients with bowing from other causes experienced only moderate improvement in speech quality. There were no implant extrusions; however, 1 implant was removed secondary to a persistent laryngocutaneous fistula in a patient who had previously undergone laryngeal irradiation. This was the only complication in this series.

Adult↗
PubMed1993

A new endotracheal tube for carbon dioxide and KTP laser surgery of the aerodigestive tract.

We have tested the fire-resistance of a new endotracheal tube designed for use in laser surgery of the upper aerodigestive tract. This Teflon/metallic-wrapped silicone tube seems capable of withstanding occasional, accidental pulsed laser impact at power settings used clinically (1 to 10 watts) without fire. On rare occasions when continuous mode is used, the tube seems capable of withstanding at least several seconds of continuous irradiation at clinical power settings without igniting. When used with other recommended safety procedures, this tube should minimize the risk of endotracheal tube fire from accidental laser impact.

Digestive System Diseases↗
PubMed1992

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗