Biomedical subjects

John L Dornhoffer

Publications and source records attributed to John L Dornhoffer.

15 recordsLinked to original sources

PubMed2006

Retrograde mastoidectomy.

The retrograde mastoidectomy technique with canal wall reconstruction is described as a primary treatment for modality for cholesteatoma. This synthesis of canal wall up (CWU) and canal wall down (CWD) techniques involves removal of a portion of the canal wall for exposure and extirpation of the cholesteatoma, followed by reestablishment of the canal wall and ossicular chain during reconstruction. This technique is possible as a single stage in over 90% of cases, including children, with recurrence rates similar to CWD surgery, but with anatomic preservation similar to CWU. Recurrent disease occurred in 16% of cases reviewed in a longer term (8 year) follow-up study. Tobacco use was associated with a higher long-term complication rate.

Cholesteatoma, Middle Ear↗

PubMed2006

Cartilage tympanoplasty.

This chapter describes two techniques for cartilage reconstruction of the tympanic membrane: the perichondrium/cartilage island flap, which uses tragal cartilage, and the palisade technique, which uses cartilage from the tragus or cymba. The perichondrium/cartilage island flap is preferred for management of the atelectatic ear and the high-risk perforation. The palisade technique is preferred in cases of cholesteatoma and when ossicular reconstruction is needed in the malleus-present situation. Descriptions of the modifications that should be taken in response to specific surgical indications are also provided and include the high-risk perforation, the ear requiring ossiculoplasty, the atelectatic ear, cholesteatoma, and pervasive Eustachian tube dysfunction.

Cartilage↗

PubMed2006

Repetitive transcranial magnetic stimulation for tinnitus: a case study.

OBJECTIVES/HYPOTHESIS: Correlate subjective improvements in tinnitus severity with restoration of cortical symmetry and sustained attention after neuronavigated low-frequency, repetitive transcranial magnetic stimulation (rTMS). STUDY DESIGN: Case study. METHODS: Positron emission tomography and computed tomography imaging (PET-CT) guided rTMS was performed on a 43-year-old white male with more than a 30 year history of bilateral tinnitus. rTMS was administered to the area of increased cortical activation visualized on PET-CT at a rate of 1 Hz for 30 minutes (1,800 pulses/session) for each of 5 consecutive days, with optimization applied on day 5 using single pulses of TMS to temporarily alter tinnitus perception. Subjective tinnitus severity was rated before and after rTMS using the tinnitus severity index with analogue scale. Attention and vigilance were assessed before and after therapy using the psychomotor vigilance task (PVT), a simple reaction time test that is sensitive to thalamocortical contributions to sustained attention. Posttherapy PET-CT was used to evaluate any change in asymmetric cortical activation. RESULTS: The most marked reduction in tinnitus severity occurred after rTMS optimization; this persisted up to 4 weeks after rTMS. PVT testing showed the patient exhibited a statistically significant improvement in mean slowest 10% reaction times after rTMS (P = .004). PET-CT imaging 2 days after the cessation of rTMS showed no changes in cortical blood flow or metabolic asymmetries. CONCLUSIONS: Low-frequency rTMS applied to the primary auditory cortex can reduce tinnitus severity, with rTMS optimization yielding the most favorable results. Beneficial changes occurring in the patient's slowest reaction times suggest that attentional deficits associated with tinnitus may also respond to low-frequency rTMS.

Adult↗

PubMed2005

Contact dermatitis to silicone after cochlear implantation.

Complications, although rare, do occur with cochlear implantation. We present a 2-year old with persistent erythema and pruritus over the implantation site with serous discharge from the implanted ear. Patch testing revealed contact dermatitis to silicone LSR-30 encasing the Nuclear Contour-24 device. Hypersensitivity was also noted to silicone LSR-30 in the Med-el device but not to silicone LSR-70 in the Advance Bionics device. Device explantation resulted in complete resolution of symptoms. The patient was then successfully reimplanted with the Advance Bionics device. Erythema and irritation at the implantation site, without leukocytosis, should prompt evaluation for silicone contact dermatitis.

Biocompatible Materials↗

PubMed2004

The use of demineralized bone matrix for mastoid cavity obliteration.

OBJECTIVE: To evaluate the use of demineralized bone matrix as a graft material for mastoid cavity obliteration in the treatment and prevention of problematic mastoid cavities. STUDY DESIGN: The study is a retrospective review of patients identified using a computerized otology database. SETTING: Tertiary care referral center. PATIENTS: Patients were included in this study if they underwent mastoid obliteration using demineralized bone matrix. INTERVENTION: Mastoid obliteration was performed for revision of a problematic mastoid cavity (n = 8) or primarily after canal wall down mastoidectomy for recurrent cholesteatoma (n = 3). MAIN OUTCOME MEASURES: Data were collected to evaluate the ability to achieve a dry ear canal. Postoperative healing time and hearing results were also assessed. RESULTS: A dry ear canal was achieved in all patients with a follow-up of 6 to 20 months (average, 14.5 mo). Eight patients (73%) had a well-healed, dry ear canal by their first postoperative visit (9 wk). One patient required 12.5 weeks to heal. Two patients (18%) had more prolonged granulation at the ear canal incision, which resolved in 17 and 28 weeks, respectively. The average preoperative pure-tone average air-bone gap was 47 +/- 14.9 dB (mean +/- SD), compared with postoperative values of 27.6 +/- 12.8 dB (p = 0.0033; paired t test). This represents an average pure-tone average air-bone gap closure of 20 dB. CONCLUSION: The use of demineralized bone matrix as a graft extender in mastoid obliteration allowed creation of a dry, smooth-contoured canal in all patients studied. A significant improvement in hearing was also obtained. Demineralized bone matrix is an acceptable graft alternative for mastoid obliteration.

Adolescent↗

PubMed2004

Retrograde mastoidectomy with canal wall reconstruction: a follow-up report.

OBJECTIVE: To evaluate long-term results of retrograde mastoidectomy with canal wall reconstruction as a single-stage technique for cholesteatoma removal. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Forty-six patients, representing 50 ears (20 pediatric and 30 adult), who had undergone surgery for cholesteatoma removal with said technique and had an average follow-up of 7.8 years. INTERVENTIONS: Temporary removal of the upper canal wall, in association with a retrograde-type mastoidectomy, for full exposure and extirpation of the disease, followed by reconstruction of the canal defect using cymba cartilage. MAIN OUTCOME MEASURES: Preoperative and short- and long-term postoperative audiogram, obtained as four-frequency pure-tone average air-bone gap. Complications, including presence of recurrent or residual cholesteatoma, need for tube insertion, perforation, and poor hearing requiring revision surgery, were also reported and correlated with the patient's tobacco use. RESULTS: The average preoperative, short-term postoperative, and long-term postoperative pure-tone average air-bone gap was 25.6+/-11.2 dB, 11.0+/-5.7 dB, and 12.4+/-6.4 dB, respectively. There were significant differences between the pre- and postoperative values (p < 0.5), but there was no significant difference between short- and long-term hearing results. Recurrent cholesteatomas were seen in eight ears (16%); pressure-equalizing tube insertion was performed postoperatively in nine ears (18%); a perforation was seen in one ear (2%); and two ears (4%) had poor hearing results requiring second-look surgery. The long-term complication rate of smokers was 79% (15 of 19), compared with 16% (5 of 31) for nonsmokers. CONCLUSION: This single-stage technique for cholesteatoma removal and canal wall reconstruction showed acceptable long-term results, but tobacco use was associated with a higher long-term complication rate.

Adolescent↗

PubMed2004

Success of cartilage grafting in revision tympanoplasty without mastoidectomy.

OBJECTIVE: Candidates for revision tympanoplasty have experienced at least one failed attempt at repair of the tympanic membrane and are, therefore, at higher risk for subsequent repair failure. The adjunctive use of mastoidectomy with tympanoplasty in those patients with noncholesteatomatous chronic otitis media is often used to decrease the risk for subsequent failure. However, at this institution, where we use cartilage tympanoplasty, mastoidectomy is rarely performed in the absence of cholesteatoma. Our objective was to assess outcomes in patients undergoing revision tympanoplasty without mastoidectomy using cartilage grafting. STUDY DESIGN: We conducted a retrospective case review. SETTING: Tertiary referral center. PATIENTS: A total of 95 patients (42 female, 53 male; 5-81 yr of age) with a recurrent perforation who were treated surgically with cartilage tympanoplasty without mastoidectomy were included in the chart review. Patients must have undergone at least one previous tympanoplasty without mastoidectomy and had to have complete audiologic and chart follow up. INTERVENTIONS: An underlay tympanoplasty technique using either a tragal cartilage-perichondrium island graft or palisaded concha cymba cartilage was used. Ossiculoplasty was performed as needed. MAIN OUTCOME MEASURE: Main outcome measures were incidence of reperforation of the grafted tympanic membrane, hearing result, and prevalence of other complications. RESULTS: Successful closure without reperforation was obtained in 90 of 95 patients (94.7%). Average postoperative pure-tone average air-bone gap was 12.2 +/-7.3 dB compared with 24.6+/-13.8 dB preoperatively (p <0.001). CONCLUSIONS: Revision tympanoplasty with cartilage provided equivalent results to tympanoplasty with mastoidectomy. Thus, mastoidectomy may not be necessary in revision tympanoplasty in the absence of cholesteatoma if the repair is made with cartilage.

Adolescent↗

PubMed2002

Natriuretic peptide receptors in the human endolymphatic sac.

OBJECTIVE: To examine human endolymphatic sac (ELS) tissue for atrial natriuretic peptide (ANP) receptor subtypes A, B, and C. DESIGN: Pilot study. METHODS: Immunohistochemical analysis of human ELS tissue specimens. The ANP receptors were characterized using the peroxidase/antiperoxidase method and polyclonal antibodies directed against each receptor subtype. The identity of the stain regarding receptor subclass was masked from the observer. Human kidney tissue known to contain all 3 receptor subtypes was used as a control. Presence of the receptor subclasses was confirmed using reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. SUBJECTS: Samples of ELS tissue were obtained at autopsy from 3 fresh cadaver specimens (6 ears) and as surgical specimens from 3 patients (1 for immunohistochemical analysis and 2 for RT-PCR) undergoing acoustic neuroma resection using the translabyrinthine approach. RESULTS: The ANP type B receptors demonstrated moderate to strong reactivity in all 7 specimens, and mild to moderate staining to the ANP type C receptor was also noted. No appreciable reactivity to the ANP type A receptor was detected using immunohistochemical techniques. All 3 receptor subclasses were detected using RT-PCR. CONCLUSIONS: The ANP receptors are found within the human ELS, with a predominance of ANP type B based on the intensity of staining. The ANPs may be involved in fluid homeostasis in the inner ear. Based on these findings, C-type natriuretic peptide may be a more effective peptide within the human ELS for fluid regulation because its binding affinity is virtually exclusive for the ANP type B receptor.

Endolymphatic Sac↗

PubMed2002

Cancer of the external auditory canal and temporal bone.

Malignant neoplasms involving the temporal bone are a relatively rare and often misdiagnosed disease. Staging of temporal bone cancer has proven difficult because of the small number of patients with this condition, the various histopathologic and histologic findings reported, and a lack of randomized trials. Of the various staging systems that have been proposed, the Pittsburgh classification appears to be the most widely accepted. A retrospective study of 31 patients with temporal bone malignancy at the University of Arkansas for Medical Sciences has led us to propose a modification of the Pittsburgh classification for early-stage lesions. This modification places more emphasis on the site of disease in the canal and less on the size of the primary tumor or degree of bony invasion. This review discusses this staging system, the management of these tumors in a multidisciplinary team approach, reconstructive options, and auditory rehabilitation.

Clinical Trials as Topic↗

PubMed2002

Tympanoplasty results in patients with cleft palate: an age- and procedure-matched comparison of preliminary results with patients without cleft palate.

OBJECTIVE: Because of continued eustachian tube abnormalities, the presence of a cleft palate repair has been thought to be associated with poor outcomes after tympanoplastic surgery. However, little published data exist regarding the results of major otologic surgery in patients with cleft palate. The objective of this study was to review our results of otologic surgery in these patients and compare results with those of age- and procedure-matched controls. METHODS: Our otologic database was used to identify patients with a repaired cleft palate who underwent otologic surgery between March 1994 and December 1999. Two control patients were identified for each cleft palate patient. Results of hearing, graft take, and need for postoperative pressure-equalizing tubes were compared. RESULTS: No significant difference existed between patients with a repaired cleft palate and control patients with regard to postoperative air-bone gap (P = 0.6805), graft survival rate (P = 1.00), and need for postoperative intubation (P = 0.457). CONCLUSION: Results in patients with cleft palate appear to be similar to those in patients without cleft palate.

Adolescent↗

PubMed2002

Hearing results with a hydroxylapatite/titanium bell partial ossicular replacement prosthesis.

OBJECTIVES/HYPOTHESIS: To study the preliminary hearing results in patients receiving a hybrid hydroxylapatite/titanium bell partial ossicular replacement prosthesis (PORP) and compare these with a cohort of patients receiving a HAPEX PORP. We hypothesized that the design of the hybrid PORP would enhance its acoustic properties. In particular, the titanium bell, which allows the prosthesis to be freestanding, would obviate the need for Gelfoam, preventing fibrosis. STUDY DESIGN: A retrospective study was made of two cohorts of patients. METHODS: A computerized otologic database was used to identify all patients implanted with either PORP. The four-frequency (500, 1000, 2000, and 3000 Hz) pure-tone average air-bone gap (PTA-ABG) and ABG values for individual frequencies were compared using the Student test. RESULTS: The PTA-ABG for the titanium bell prosthesis was 9.8 +/- 5.7 dB, compared with 13.2 +/- 8.3 dB for the HAPEX PORP, which was statistically significant ( P<.05). The average ABG values at 500 and 1000 Hz were also statistically significantly improved with the titanium bell PORP ( P<.05). CONCLUSIONS: The titanium bell PORP showed improved postoperative results for the PTA-ABG and at 500 Hz and 1000 Hz. The prosthesis is freestanding and may provide better coupling with the capitulum, factors which may lead to improved hearing results in the lower frequencies.

Adolescent↗

PubMed2002

Bioactive glass ceramic particles as an alternative for mastoid obliteration: results in an animal model.

HYPOTHESIS: This study was conducted to evaluate the use of the bioactive glass ceramic particulate NovaBone Bioglass as a graft material for mastoid cavity obliteration in an animal model. BACKGROUND: Canal wall down procedures in otologic surgery may result in a problematic mastoid cavity. Mastoid cavity obliteration can potentially prevent or correct this problem. Many techniques and implant materials have been used for mastoid obliteration, but no single graft material has proved to be ideal. METHODS: Mongolian gerbils received tympanic bulla obliteration using the NovaBone Bioglass particulate. Nine weeks after implantation, the animals were killed, and histologic sections were prepared. Histologic evaluation was performed to evaluate new bone formation within the implant. RESULTS: Wound healing occurred without complication. Mature trabecular bone was observed throughout the entire thickness of the implant material. Extensive neovascularity was observed within the graft material. There was no histologic evidence of inflammatory reaction or short-term resorption. CONCLUSIONS: The extensive new bone formation obtained with bioactive glass ceramic particles in this study makes this material a potential alternative resource as a graft material for mastoid obliteration.

Animals↗

PubMed2002

Atrial natriuretic peptide receptor upregulation in the rat inner ear.

The purpose of this study was to further examine whether fluid homeostasis in the endolymphatic system could be regulated by a locally effective paracrine system involving atrial natriuretic peptides (ANPs) and their receptors. We assessed the biologic activity of the 3 ANP receptors (ANP-A, ANP-B, ANP-C) in the rat inner ear by measuring receptor upregulation after inner ear administration of ANPs. After appropriate anesthesia, female Lewis rats were injected with ANP via the round window. The animals were sacrificed 24 hours later, and RNA was isolated for reverse transcription-polymerase chain reaction (RT-PCR). Electrophoresis of RT-PCR products showed the presence of all 3 ANP receptor genes in both injected and control animals. Gene expression was significantly higher 24 hours after injection. These findings demonstrate that ANP receptors in the inner ear can be upregulated after injection of ANPs.

Animals↗

PubMedDate not supplied

Effects of drug countermeasures for space motion sickness on working memory in humans.

Space motion sickness (SMS) is a problem during the first 72 h of space flight and during transitions from different gravity environments. There currently are no effective drug countermeasures for SMS that also accommodate the retention of optimal cognitive function. This creates a dilemma for astronauts because cognitive skills are particularly important during gravity transitions (e.g., take-off and landing). To quantify the cognitive side effects of potential drug countermeasures, an automated delayed matching-to-sample (DMTS) procedure was used to assess visual working memory before and after drug countermeasures (meclizine 25 mg, scopolamine 0.4 mg, promethazine 25 mg, or lorazepam 1 mg, given orally approximately 45 min prior to testing) and/or the induction of SMS by vestibular stimulation in a rotary chair (spinning). Sixty-seven normal healthy volunteers (mean age, in years, 26.6+/-4.8 S.D.; 24 females and 43 males) each participated in two test sessions, one 'off' drug and one 'on' drug. Spinning by itself significantly decreased task accuracy (Acc) and choice response speed, especially at longer recall delays. Meclizine alone had no effect on Acc or speed with or without spinning. Scopolamine alone decreased Acc, and with spinning, slowed speed. Promethazine alone had no adverse effect, but combined with spinning, decreased Acc and speed. Lorazepam alone decreased speed, and with spinning, decreased Acc. The data suggest that, at clinically useful doses, the rank order of the drugs with the best cognitive profiles is meclizine>scopolamine>promethazine>lorazepam.

Adult↗

PubMedDate not supplied

Effects of rotation on the sleep state-dependent midlatency auditory evoked P50 potential in the human.

Sopite syndrome, characterized by loss of initiative, sensitivity to normally innocuous sensory stimuli, and impaired concentration amounting to a sensory gating deficit, is commonly associated with Space Motion Sickness (SMS). The amplitude of the P50 potential is a measure of level of arousal, and a paired-stimulus paradigm can be used to measure sensory gating. We used the rotary chair to elicit the sensory mismatch that occurs with SMS by overstimulating the vestibular apparatus. The effects of rotation on the manifestation of the P50 midlatency auditory evoked response were then assessed as a measure of arousal and distractibility. Results showed that rotation-induced motion sickness produced no change in the level of arousal but did produce a significant deficit in sensory gating, indicating that some of the attentional and cognitive deficits observed with SMS may be due to distractibility induced by decreased habituation to repetitive stimuli.

Adult↗