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Biomedical subjects

C A O'Connor

Publications and source records attributed to C A O'Connor.

17 recordsLinked to original sources
PubMed1996

Intraoperative auditory monitoring in acoustic neuroma surgery.

Intraoperative auditory monitoring is a useful adjunct that is currently evolving. Near-field monitoring techniques such as electrocochleography and direct eighth nerve compound action potential are being used more frequently. The use of these two techniques is compared in 26 patients undergoing hearing preservation acoustic neuroma resection. Overall, 9 (35%) of the 26 patients had their hearing preserved. Three (23%) of the 13 with electrocochleography monitoring and 6 (46%) of the 13 with direct compound action potential monitoring had hearing preserved after surgery. Although there was a suggestion of improved results with direct compound action potential monitoring, the results were not statistically different. It was noted that lack of electrical response at the completion of the procedure (regardless of monitoring technique) was correlated with poor postoperative hearing, whereas the presence of a waveform at termination in no way predicted satisfactory postoperative hearing. The two techniques and their advantages and disadvantages are discussed.

Action Potentials↗
PubMed1995

Conservative management of patients with small acoustic tumors.

Of 432 patients referred for treatment of their cerebellopontine angle tumors, 53 with acoustic neuromas were managed initially without intervention but with adequate follow-up. Mean presenting tumor size in this subgroup of patients was 0.98 cm (range, 0.2 to 3.0 cm), and average growth rate was 0.16 cm per year. Twenty-one patients demonstrated tumor growth with a mean follow-up interval of 1.9 years. Of these 21 patients, 14 underwent microsurgical excision, 4 received radiation, 2 continued to be observed and 1 was lost to follow-up. The remaining 32 (60%) had no demonstrable growth with a mean follow-up of 2.13 years. Of these patients, 29 continue to be followed and 3 were lost to follow-up. Of the information evaluated, the only statistically significant relationship is with larger tumor size in elderly patients--most likely reflecting the propensity to opt for conservative treatment in elderly patients. Tumor growth rate was unrelated to presenting tumor size or patient age, which suggests that conservative treatment may be appropriate in selected patients.

Adult↗
PubMed1993

Multichannel cochlear implantation in the rehabilitation of post-traumatic sensorineural hearing loss.

Although there is a 17% to 56% incidence of sensorineural hearing loss following head injury, to our knowledge cochlear implants have not been used in treatment of this problem in patients with cognitive deficits and aphasia. We report our experience with multichannel cochlear implantation in one such patient. The patient is a 26-year-old man with bitemporal lobe damage and T-11 paraplegia. The clinical profile showed emotional lability, perseveration of thought, impulsivity, good visuospatial orientation, and adequate use of oral and written language in conveying basic needs. Audiologic evaluation showed profound sensorineural hearing loss. Middle latency responses suggested intact thalamocortical pathways. The patient was provided with a multichannel cochlear implant with improvement in his speech recognition and functional skills. We conclude that the cochlear implant should be considered in patients with traumatic sensorineural hearing loss with relatively intact cognitive skills.

Adult↗
PubMed1993

Recent advances in surgery of the temporal bone and skull base.

Remarkable advances have been made in the field of neuro-otologic and skull base surgery within the past decade. Each component of the "disease model"--prevention, diagnosis, therapy, and rehabilitation--is undergoing rapid progress. The purpose of this paper is to highlight only a few of these achievements. Each topic chosen has witnessed recent advancement in one aspect of the disease model. Neurofibromatosis (prevention) has been subjected to chromosomal mapping, allowing for genetic counseling. Intraoperative facial nerve monitoring (diagnosis) has allowed improved anatomic and functional preservation of this nerve during surgery. Embolization of glomus tumors (therapy) has rendered these difficult lesions more surgically manageable, and cochlear implantation (rehabilitation) has allowed the profoundly deaf to play a more active role in society. Each of these topics is briefly discussed as it relates to the temporal bone surgeon.

Cochlear Implants↗
PubMed1992

Hemophilus influenza infection of an implantable insulin-pump pocket.

OBJECTIVE: To increase awareness of adverse events associated with the use of implantable insulin pumps. RESEARCH DESIGN AND METHODS: A descriptive case report of a pump implant infection. RESULTS: This is a case report of one implanted insulin pump-pocket infection among a series of 15 patients. After exposure to a child with a respiratory infection on PID 30, V.L.C. (the patient) developed a fulminant pump-pocket infection. H. influenza was recovered from it. Despite aggressive antibiotic therapy, the infection could not be controlled. Insulin delivery ceased, and the pump was explanted. The pump-pocket infection rapidly resolved with pump removal, permitting later reimplantation. CONCLUSIONS: We have adopted the American Heart Association indications and antimicrobial prophylaxis regimens recommended for prevention of endocarditis in patients with prosthetic values for patients with implanted insulin pumps.

Adult↗
PubMed1990

Computed tomography: how accurate a predictor for cochlear implantation?

Cochlear implantation is an accepted medical treatment for profound bilateral postlinguistically acquired hearing loss. Because cochlear implants are still in the process of development, a detailed evaluation of the results of implantation is essential. However, the capability of predetermining the auditory benefit of a cochlear implant is limited and depends upon a number of factors. This report focuses upon the ability of computed tomography (CT) to predict surgical success and audiological results of multichannel cochlear implantation. It also addresses how the disease state might affect the functional benefit of the implant. After undergoing routine clinical and audiological evaluations, 28 cochlear implant candidates underwent CT scans in order to evaluate cochlear patency prior to surgery. Subsequently, 24 patients were implanted with either a single-or 22-channel device. Surgical findings were noted and postoperative audiological assessments of sound detection and speech discrimination were made. The CT risk factors that diminish the likelihood of a successful cochlear implant result are discussed based upon a retrospective comparison of preoperative CT results, surgical findings, and postsurgical audiological evaluations of the 14 patients who received a 22-channel implant. Analysis of the predictive capability of CT will allow clinicians to use that procedure more effectively in the presurgical assessment of cochlear implant candidates.

Adult↗
PubMed1989

Age considerations in acoustic neuroma surgery: the horns of a dilemma.

Experience has shown that early removal of acoustic tumors results in less morbidity because the rate of surgical complications increases with tumor size. Nevertheless, acoustic tumors are benign and grow slowly--facts that support conservatism in elderly patients. We managed 21 patients with acoustic tumors over the age of 65. Eleven patients underwent immediate surgical excision. Ten patients were monitored clinically and with serial magnetic resonance imaging (MRI) or computed tomographic (CT) scans. To date, two of these patients have required surgical excision because of continued tumor growth. Our experience managing these patients both surgically and with "watchful waiting" is the subject of this report.

Adolescent↗
PubMed1987

Brain herniation and space-occupying lesions eroding the tegmen tympani.

Technological advances in neuroradiology and the development of skull base surgery in neurotology have improved diagnosis and management of lesions eroding the tegmen tympani. The diagnosis of brain hernia is to be suspected in patients with a history of complicated chronic ear surgery and a slowly developing pulsatile mass with CSF leak. Patients are best evaluated in the upright position, with an otomicroscope and by magnetic resonance imaging (MRI). Over 6 years, our group has treated seven patients with eight space-occupying lesions eroding the tegmen. Five of the lesions were repaired with a temporalis muscle flap, 2 with fascia and bone, and 1 with Marlex. A review of new technology in the diagnosis of brain hernia and a modification of previous techniques is given.

Adolescent↗
PubMed1986

Upper gastrointestinal bleeding: predictors of outcome.

We reviewed the records of 115 patients treated for upper gastrointestinal (UGI) bleeding on a general surgical and trauma service from January 1981 to June 1984. Clinical variables were analyzed with regard to three outcome criteria: mortality rate, blood transfusion requirements, and need for operation. Endoscopy was performed in all patients, usually within 24 hours of detection of bleeding. Thirty-six patients required greater than or equal to 5 U of blood, 27 patients required an operation for bleeding, and 26 patients (23%) died in the hospital. In 19 patients, death was attributed to the patient's underlying disease; in seven patients, death was due to bleeding or operation. Significant predictors of death were: age greater than or equal to 60 years old (p less than or equal to 0.02), disease in three organ systems (p less than 0.05), 5 U transfusion requirement (p less than 0.001), operation for bleeding necessary (p less than 0.03), lung/liver disease (p less than 0.03), and recent stress of major operation, trauma, or sepsis. Mortality rates were highest for bleeding varices (36%) and lowest for duodenal ulcers (7.7%) and gastric ulcers (15.8%). Endoscopy accurately determined the cause of UGI bleeding in most patients. The data suggest that the unchanging mortality rate for UGI bleeding is largely due to underlying disease or injury for which the success of current treatment is limited.

Adult↗
PubMed1984

Comparison of recurrence rates of calculi of the bladder in patients with indwelling catheters following vesicolithotomy, litholapaxy and electrohydraulic lithotripsy.

This retrospective review is the first to compare recurrence rates of calculi of the bladder following each of the three common methods. In 39 patients with bladder calculi and indwelling catheters, the recurrence rate of calculi of the bladder within two years was significantly greater following litholapaxy (44.1 per cent) or EHL (50.0 per cent) than vesicolithotomy (7.4 per cent). The average stone-free interval was shorter after litholapaxy (18.4 months) or EHL (13.8 months) than vesicolithotomy (70.8 months).

Adolescent↗
PubMed1982

A clinicopathologic correlation of mammographic parenchymal patterns and associated risk factors for human mammary carcinoma.

The five-year screening experience for 10,131 asymptomatic women evaluated at the Louisville Breast Cancer Detection Demonstration Project (LBCDDP) disclosed 144 breast carcinomas in 1,209 patients (12%) aged 35 to 74 years in whom 904 biopsies and 305 aspirations were performed. This study included 44,711 high-quality xeromammograms (XM) prospectively classified by the modified Wolfe mammographic parenchymal patterns into low-risk (N(1), P(1)) versus high-risk (P(2), DY) groups, with expansion of the P(2) cohort into three additional categories. Using BMDP computer-program analysis, each XM pattern was collated with 21 nonneoplastic and 18 malignant pathologic variables and commonly associated risk factors. A separate analysis of epithelial proliferative and nonproliferative fibrocystic disease of the breast (FCDB) was performed. The histopathology for each biopsy, with distinction of FCDB and neoplasms, was analyzed with regard to the statistical probability of influencing the XM pattern. An average of 1.05 biopsies per patient were performed in women with findings suggestive of carcinoma at clinical and/or XM examinations. An equal distribution of the N(1), P(1), and P(2) DYXM patterns was observed in the 10,131 screenees. Of 8.5% of the screened population having biopsies, 623 were observed to have nonproliferative FCDB and 137, proliferative FCDB. For women 50 years of age or younger, these pathologic variables were seen more frequently in the P(2) DY patterns (p < 0.001), whereas no difference in XM pattern distribution was observed for the screenee 50 years of age or older for proliferative FCDB (p = 0.65). Sixteen percent of the biopsied/aspirated lesions were carcinomas, yielding a biopsy/cancer ratio of 6.25:1. These in situ and invasive neoplasms were more commonly (p < 0.04) observed in 55% of the P(2) (P(2f), P(2n), P(2c)) categories, while 64% of all cancers appeared more frequently in the P(2) DY subgroup (p <0.001), compared with this pattern in the screened population. An equal distribution frequency of the XM classification existed for screenees 50 years of age or older with cancer (p = 0.50), while screenees 35-49 years of age were more often observed to have the high-risk P(2), DY patterns (p <0.001). Analysis of 1,759 histologic characteristics in biopsies of 863 patients with FCDB revealed ductal and lobular hyperplastic lesions, sclerosing adenosis, or epithelial cyst(s) to be the major constituents of 64-69% of the high-risk P(2) (P(2f), P(2n), P(2c)) image (p < 0.001). These data suggest that XM parenchymal patterns observed in asymptomatic screenees incompletely correlate with known pathologic variables and risk factors. Additionally, benefit for recognition of these preinvasive proliferative pathologic factors and carcinomas appears restricted to the younger screenee. The clinical integration of these risk factors with XM patterns may allow preselection of patients deserving of frequent follow-up for breast cancer; however, these data do not support the contention that Wolfe XM patterns are predictors for screening strategies or that they decisively enhance patient management.

Adult↗