Ensemble machine learning classification of daily living abilities among older people with HIV.

Background: clinically relevant methods to identify individuals at risk for impaired daily living abilities secondary to neurocognitive impairment (ADLs) remain elusive. This is especially true for complex clinical conditions such as HIV-Associated Neurocognitive Disorders (HAND). The aim of this study was to identify novel and modifiable factors that have potential to improve diagnostic accuracy of ADL risk, with the long-term goal of guiding future interventions to minimize ADL disruption.

Preservation of auditory brainstem response thresholds after cochleostomy and titanium microactuator implantation in the lateral wall of cat scala tympani.

Hypothesis: The safety of implanting a titanium microactuator into the lateral wall of cat scala tympani was assessed by comparing preoperative and postoperative auditory brainstem response (ABR) thresholds for 1 to 3 months.

Background: The safety of directly stimulating cochlear perilymph with an implantable hearing system requires maintaining preoperative hearing levels. This cat study is an essential step in the development of the next generation of fully implantable hearing devices for humans.

Revision stapedectomy.

During the past decade, the evolution of surgical techniques and philosophy for revision surgery after stapedectomy has accelerated. Lasers, new surgical techniques, and new prostheses now permit the precise identification and reliable correction of the conductive problem, while reducing the risk of postoperative sensorineural hearing loss that plagued nonlaser revision techniques.

Causes of conductive hearing loss after stapedectomy or stapedotomy: a prospective study of 279 consecutive surgical revisions.

Objective: To analyze the causes for residual or recurrent conductive hearing loss following stapedectomy or stapedotomy and then propose surgical techniques to avoid these complications.

Study Design: Prospective study of 279 consecutive stapedectomy or stapedotomy revisions performed by the author.

Setting: Tertiary referral center.

Carbon dioxide lasers for otosclerosis.

Over the past eight years, the senior author (SGL) has sought the ideal microsurgical laser for otosclerosis surgery. This quest required learning the principles of laser physics and of the interactions of light with matter. Rather simple thermocouple experiments were performed in the laboratories of the Midwest Ear Foundation (MEF) to confirm some of what was predicted from these principles.

Lasers for otosclerosis--which one if any and why.

Laboratory stapedotomy and stapedectomy revisions were performed in human temporal bones while pyroelectric wave energy analyzers and ultrasensitive thermocouples measured energy absorption at the stapes footplate and in the vestibule. Analysis of these data shows that the visible lasers (argon and KTP-532) possess ideal optical properties and precision for otosclerosis surgery but conversely have less than ideal tissue characteristics. The CO2 laser possesses ideal tissue characteristics.

CO2 laser for otosclerosis: safe energy parameters.

Safe energy parameters for each Sharplan CO2 laser model (734, 1040, 1100A) were established in the laboratory. Ultrasensitive pyroelectric detectors analyzed the precise energy package delivered to the operative field with each of these power setting. Subsequently, 0.

CO2 laser stapedotomy.

This clinical study was preceded by two laboratory experiments. The first experiment compared temperature changes in the vestibule while vaporizing a 0.6-mm stapedotomy with Argon, KTP-532, and CO2 lasers.

Lasers for otosclerosis: CO2 vs. Argon and KTP-532.

The concept of using laser energy to perform stapedotomy and stapedectomy revision is an attractive one. Precision of vaporizing a perfectly round 0.6- to 0.

Homograft (allograft) tympanoplasty update.

If homograft tympanoplasty is to be of value, specific instances in which homograft tympanic membrane, malleus, and incus (TMMI) provide significant hearing and anatomical advantages over standard techniques should be identified. This author has performed 305 homograft tympanoplasties limited to the reconstruction of the severely damaged middle ear. Indications include: previous failure with standard tympanoplasty techniques; high risk of anatomic or hearing failure with standard techniques (total perforation with absent malleus, slag burns); reconstruction of radical mastoidectomy; congenital aural atresia.

Reconstruction of hearing when malleus is absent: TORP vs. homograft TMMI.

To study the most appropriate ossicular reconstruction of patients with an absent malleus, a comparison was made utilizing a homograft tympanic membrane with attached malleus and shaped incus (TMMI) columella and the alternative use of underlay fascia tympanoplasty with a cartilage covered TORP. Forty-six patients were reconstructed with a homograft TMMI and 38 with cartilage covered TORP and underlay fascia technique; 4.5 years postoperatively, 84% of those patients reconstructed with a homograft TMMI maintained an average A/B gap of 25 dB or better.

Homograft tympanoplasty in perspective. A long-term clinical-histologic study of formalin-fixed tympanic membranes used for the reconstruction of 125 severely damaged middle ears.

This seven and a half year clinical-histologic study evaluates the effectiveness of buffered, formaldehyde-fixed homograft tympanic membranes for reconstructing the severely damaged middle ear in 125 consecutive patients. Indications for use of homograft tympanoplasty were limited to those cases in which standard tympanoplasty had already failed to produce a satisfactory hearing or anatomic result (i.e.

Complications of homograft tympanoplasty.

The use of a homograft tympanic membrane with an attached malleus has provided an excellent alternative for reconstructing the severely damaged middle ear. I have limited homograft tympanoplasty to four specific indications: previous failure of standard tympanoplasty techniques, high risk of failure (total perforation, absent malleus, slag burns), reconstruction of radical mastoidectomy, and congenital aural atresia. Homograft tympanoplasty has provided a 94 per cent incidence of anatomic success in these severely damaged middle ears.

Does the Silastic Eustachian Tube prosthesis improve eustachian tube function?

This clinical study attempts to evaluate the effectiveness of Eustachian tube function in 30 ears, 11-29 months after insertion of the Silastic Eustachian tube prosthesis (SETP). Indications for the SETP were limited to persistent Eustachian tube dysfunction. Preoperatively, 13 patients had intact tympanic membranes with persistent serous otitis media.

Why not the eighth nerve? Neurovascular compression--probable cause for pulsatile tinnitus.

Carotid arteriograms on three patients with unilateral pulsatile tinnitus demonstrated an ipsilateral atypical trigeminal artery extending from the cavernous portion of the internal carotid artery to form the posterior inferior cerebellar artery. Illustrations and a dissection of a human fetus with a similar finding show this artery crossing the cochlear nerve near its insertion in the pons. Evidence is presented suggesting that neurovascular compression of the eighth nerve is the source of pulsatile tinnitus in these patients.

Hemilaryngectomy for T3 (fixed cord) epidermoid carcinoma of larynx.

This clinicopathologic study was undertaken to determine whether true vocal cord fixation produced by epidermoid carcinoma is an absolute contra-indication to treatment by hemilaryngectomy. In a consecutive series of 114 hemilaryngectomies performed at McMillan Hospital (1960-1967) for previously untreated epidermoid carcinoma, 18 patients had fixation of the involved true vocal cord. Each hemilaryngectomy specimen (serial step sections in the longitudinal plane) was re-examined to ascertain the cause of vocal cord fixation; the adequacy of margin; and the presence of blood vessel, nerve sheath and cartilage invasion.

The significance of positive margins in hemilaryngectomy specimens.

This clinicopathologic study was undertaken to determine the meaning of surgical margins "involved" with carcinoma. The fate of hemilaryngectomy patients whose specimens had this finding was comparared with that of patients who had "uninvolved" margins. A consecutive series of 111 hemilaryngectomies performed for previously untreated invasive epidermoid carcinoma was analyzed.