The effects of posteroventral pallidotomy on balance function in patients with Parkinson's disease.

Parkinson's disease is a chronic, progressive neurodegenerative disorder resulting from dopaminergic cell loss in the pars compacta of the substantia nigra. Conventional treatment of Parkinson's disease consists of pharmacological replacement of dopamine. A treatment alternative, posteroventral pallidotomy (PVP), has been used for medically intractable stages of the disease. The purpose of this study was to evaluate the effects of PVP on balance function, as measured by dynamic posturography, in patients with medically intractable Parkinson's disease. Five subjects were studied within 2 days prior to and within 6 months following PVP. Pretreatment abnormalities were found in vestibular, visual, and somatosensory processing in balance function. Posteroventral pallidotomy resulted in improvement in vestibular compensation of posture in some patients, which may be at least partially due to an improvement in latencies to respond to changes in stance. Dynamic posturography is an effective tool in the evaluation of balance and posture in patients with advanced Parkinson's disease.

Hearing improvement after middle fossa resection of vestibular schwannoma.

OBJECTIVE: The preoperative, intraoperative, and postoperative variables of patients experiencing hearing improvement after middle fossa resection of vestibular schwannomas were evaluated as potential prognostic indicators. STUDY DESIGN: Retrospective case review with new objective postoperative data collected on patients with documented hearing improvement. SETTING: California Ear Institute at Stanford and Stanford University Hospital, a tertiary referral center. PATIENTS: The patient group consisted of 30 consecutive patients undergoing middle fossa approach to vestibular schwannoma between October 24, 1994, and November 11, 1998. INTERVENTION: Hearing preservation surgery via the middle cranial fossa approach was performed on all patients. MAIN OUTCOME MEASURES: Pure-tone averages (PTAs) and speech discrimination scores (SDS) were used to document hearing preoperatively and postoperatively. Preoperative electrophysiologic studies of auditory brainstem response, electronystagmography, electrical neuronography, transient evoked otoacoustic emissions, and distortion product otoacoustic emissions were evaluated. Intraoperative continuous nerve action potential and auditory brainstem response tracings were reviewed. Postoperative auditory brainstem response and transient evoked otoacoustic emissions were obtained when possible on patients whose hearing improved. Statistical analysis was completed using Student's t test and chi-square test. RESULTS: Seventeen (57%) of 30 patients with tumors ranging from 2 to 31 mm maintained hearing postoperatively. Among patients with hearing preservation, 7 (41% or 23% of the overall group) exhibited hearing improvement (PTA 2 improved by > or =5 dB and/or SDS improved by > or =12%). Three of these 7 patients moved from nonfunctional (AAOHNS class C/D) to functional (AAOHNS class A/B) categories. All patients who enjoyed postoperative hearing improvement had preoperative absence or abnormality of ABRs. No patient with normal preoperative ABR experienced hearing improvement. Hearing improvement patients also had lower preoperative caloric function on electronystagmography compared with the entire group (p < 0.02) and were more likely to have superior vestibular nerve tumors. No differences were noted for electrical neurography and otoacoustic emissions. CONCLUSIONS: Middle fossa resection of vestibular schwannoma offers patients the possibility of hearing improvement after treatment. The chance of hearing improvement is significantly higher than with other forms of treatment such as radiation therapy or translabyrinthine surgery. Although preoperative ABR abnormality may be an indicator of poor prognosis for hearing preservation, those patients who enjoy hearing improvement come from the group of patients with abnormal preoperative ABRs. Other factors identified as associated with hearing improvement include poor SDS with more normal PTA 2, and significantly decreased electronystagmographic caloric function (as an indicator of superior vestibular nerve tumors). Hearing improvement to the functional range after surgical resection is possible in some patients previously thought to be poor candidates for hearing preservation attempts. Hearing improvement may continue for many months after surgery.

Implementation of a clinical pathway in management of the postoperative vestibular schwannoma patient.

OBJECTIVE: The purpose of the study was to evaluate the effectiveness of a new clinical pathway in management of patients with postoperative vestibular schwannoma. The impact on duration of hospitalization and quality of care was evaluated. STUDY DESIGN: The study was a retrospective review of 59 consecutive patients undergoing surgical intervention for vestibular schwannoma between January 1995 and July 1999. METHODS: A new clinical pathway for management of postoperative vestibular schwannoma patients was implemented at The California Ear Institute at Stanford (Palo Alto, CA) in January 1995. All patients undergoing surgical intervention subsequent to initiation of the pathway were included in the study. Data including surgical approach, patient age, sex, and tumor size were included. Duration of hospitalization and postoperative complications were recorded. During the same time period, data for patients undergoing radiation therapy for vestibular schwannomas were evaluated for length of hospital stay and in-hospital complications. Data were compared with norms recorded in the literature for duration of hospitalization and complications following surgical intervention. RESULTS: Fifty-nine patients underwent 35 middle fossa approaches and 24 translabyrinthine approaches to their tumors. The average patient age was 53 years; there were 34 female and 25 male patients. The average length of hospital stay was 3.83 days (SD = 1.4 days) with a range from 2 to 10 days. Postoperative complications were observed in 19% of patients, including eight (13%) cerebrospinal fluid (CSF) leaks, two requiring lumbar drains (3.4%); one hematoma (1.6%), one postoperative fever (1.6%), and one dural tear with associated hyponatremia (1.6%). These results compared favorably with previously recorded average hospital stays of 5.95 to 9.5 days 1,5-7 and CSF leak complication rates of 7% to 15%.9,10 CONCLUSIONS: Implementation of a clinical pathway for management of the patient with postoperative vestibular schwannoma improves efficiency of patient care, allowing decreased duration of hospitalization. This goal is achieved without increasing complication rates and, in our experience, actually improving the quality of clinical care. The cost-effectiveness of clinical pathways may become increasingly important in a managed care-driven environment.

Complications of venous insufficiency after neurotologic-skull base surgery.

OBJECTIVE: To characterize the incidence and complications resulting from venous insufficiency after neurotologic-skull base surgery. STUDY DESIGN: Retrospective case review of >3,500 cases. SETTING: Tertiary referral center, inpatient surgery. PATIENTS: Six patients: four with complications related to chronic venous insufficiency and two with complications related to acute venous insufficiency. INTERVENTION(S): Medical (steroids, acetazolamide, hyperventilation, mannitol) and surgical (lumboperitoneal shunt, optic nerve decompression, embolectomy) interventions were undertaken. MAIN OUTCOME MEASURE(S): Chronic venous insufficiency: nonobstructive hydrocephalus manifested by headache, disequilibrium, and papilledema with resultant visual loss. Acute venous insufficiency: acute nonobstructive hydrocephalus resulting in mental status abnormalities in the postoperative period. CONCLUSIONS: (1) Incidence of 1.5 per 1,000 cases. (2) Acute and chronic forms with different pathogenesis. (3) Acute form presents postoperatively with change in consciousness and herniation, and may proceed to death. (4) Chronic form presents months or years postoperatively with headache, disequilibrium, and visual changes from papilledema. (5) Occurs almost solely in patients with preoperative abnormalities of the venous collecting system. (6) Causes mental status changes postoperatively.

Comparison of argon and CO2 laser stapedotomy in primary otosclerosis surgery.

PURPOSE: The primary use for the laser in otosclerosis surgery is to create a stapes footplate fenestration that obviates the need for mechanical footplate removal. Experimental studies that evaluate the potential safety of visible (argon and potassium-titanyl-phosphate [KTP]) and invisible (CO2) light laser systems in stapes surgery report conflicting results. The purpose of this study is to compare the clinical safety and efficacy of the CO2 and argon laser systems when used for primary laser stapedotomy. MATERIALS AND METHODS: A retrospective case review of 124 primary laser stapedotomies using either the argon (n = 59) or CO2 (n = 65) laser was performed. Data consisted of pre- and postoperative air and bone conduction audiometry, speech discrimination scores (SDS), intraoperative findings, and postoperative complications. Between group differences (argon v CO2) were sought using standard statistical methodology. RESULTS: The argon and CO2 laser groups were comparable with regards to age, sex, preoperative air-bone gap, and laterality. Mean preoperative air and bone conduction pure-tone average (PTA) and SDS were somewhat higher in the CO2 laser group (P < .05). Postoperatively, both groups showed similar results in mean change in air conduction PTA, air-bone gap, and SDS, as well as in the frequency of complications. There were no anacoustic ears in either group. CONCLUSIONS: The results suggest that the argon and CO2 laser systems are comparable with regards to safety and efficacy when used by experienced surgeons for stapedotomy.

Cochlear implantation: minimal hair removal technique.

This prospective study was undertaken to evaluate the safety and patient acceptance of minimal hair removal during cochlear implantation. Forty-six consecutive patients (17 adults, 29 children; age range 13 months to 84 years) received cochlear implantation with a minimal hair removal technique. A questionnaire was used to evaluate acceptance and value of this technique among the first 15 patients and parents. Postoperative examinations were completed 1 and 4 weeks after implantation. Patients were monitored for complications, which included 3 cases of transient seroma, 2 cases of transient dysequilibrium, 2 individual electrode failures, and 1 facial nerve stimulation. Importantly, no wound infections were documented. Use of a small shave technique did not increase surgical risk. This technique has proved to be cosmetically and psychologically more desirable for the patients and their families than complete hair removal in the operative field.

Acoustic neuroma surgery: use of cochlear nerve action potential monitoring for hearing preservation.

OBJECTIVES: To compare the hearing preservation results obtained with use of two intraoperative eighth nerve monitoring methods, cochlear nerve action potential (CNAP) and auditory brainstem response (ABR), during complete acoustic neuroma (AN) resection. STUDY DESIGN: Retrospective. SETTING: Tertiary referral center. PATIENTS: Thirty-three consecutive patients who underwent hearing preservation AN surgery. INTERVENTIONS: Intraoperative monitoring by CNAP and/or ABR during AN resection. MAIN OUTCOME MEASURE: Postoperative hearing. Hearing preservation was considered achieved for pure-tone average < or =50 dB and speech discrimination > or =50%. RESULTS: Thirty-two patients met inclusion criteria for the study. Monitoring was successfully performed in 23 of 25 patients (92%) who underwent attempted CNAP monitoring and 13 of 27 (48%) who underwent attempted ABR monitoring. When tumor size was < or =20 mm in greatest dimension, hearing preservation was achieved in 12 of 18 patients (67%) monitored with CNAP, versus 2 of 8 patients (25%) not monitored with CNAP (p = 0.05). Monitoring by ABR did not improve hearing preservation rates compared with those not monitored with ABR (40% vs. 63%). At the completion of surgery, the presence or absence of CNAP predicted the presence or absence of hearing preservation in 18 of 23 cases (p = 0.01), while ABR successfully predicted hearing results in 10 of 13 cases (p = 0.05). CONCLUSIONS: When CNAP and ABR monitoring techniques during AN surgery were compared, CNAP was more frequently obtainable. Monitoring by CNAP was significantly associated with a higher chance of hearing preservation. Monitoring by ABR did not have a positive influence on hearing preservation results. Both ABR and CNAP were useful for predicting postoperative hearing.

Vagal nerve monitoring in surgery of the skull base: a comparison of efficacy of three techniques.

OBJECTIVE: To compare three techniques of monitoring the vagal nerve during skull base surgery using laryngeal electromyography (EMG). STUDY DESIGN: Prospective comparison. SETTING: California Ear Institute at Stanford, tertiary referral center. PATIENTS: Seventeen consecutive patients undergoing lateral skull base surgery potentially placing the vagal nerve at risk. INTERVENTIONS: Each patient was simultaneously monitored intraoperatively with three separate EMG techniques: 1) endolaryngeal surface electrodes mounted on an endotracheal tube (ETT) (Xomed Surgical Products, Inc., Jacksonville, FL); 2) endoscopically placed endolaryngeal thyroarytenoid intramuscular hookwire electrodes; and 3) percutaneously placed cricothyroid intramuscular hookwire electrodes. MAIN OUTCOME MEASURES: Sensitivity, reliability, response magnitude, incidence of false-positive responses, and complications were recorded. Preoperative and postoperative vagal nerve function was noted. RESULTS: The study was completed in 13 patients. The endolaryngeal intramuscular electrode technique responded at the lowest current stimulus (mean, 0.073 mA) with the highest average magnitude response. It responded in 100% of patients. The percutaneous intramuscular technique was similarly sensitive (mean stimulus, 0.089 mA) with a large average magnitude response but was much less reliable (responded in 69.2% of patients). The Xomed ETT was less sensitive (mean stimulus, 0.120 mA), had the lowest average magnitude response, and demonstrated medium reliability (responded in 76.9% of patients). The ETT exhibited the lowest incidence of spontaneous false-positive EMG activity. No complications were noted, and vagal nerve function was not compromised in any patient. CONCLUSIONS: Although the Xomed ETT exhibited ease of placement and a low false-positive response rate, it demonstrated lowest sensitivity compared with electrodes placed intramuscularly. The percutaneous intramuscular electrode technique was the least reliable, likely related to blind insertion, making it a less-desirable technique. Because of its highest relative sensitivity and reliability, the endolaryngeal intramuscular electrode technique of vagal monitoring is best supported by this study.

Acoustic neuroma surgery: absent auditory brainstem response does not contraindicate attempted hearing preservation.

OBJECTIVE: Absence of auditory brainstem response (ABR) waveforms has been associated with a poor likelihood of hearing preservation following resection of acoustic neuromas. Our experience is reviewed for patients with absent preoperative ABR regarding hearing preservation, hearing improvement, and return of ABR. STUDY DESIGN: Retrospective review of 22 cases of acoustic neuroma resection. Nine patients with absent preoperative ABR were identified. All underwent tumor resection utilizing intraoperative cochlear nerve action potential (CNAP) monitoring. Postoperative hearing results and ABR waveforms were examined. METHODS: Charts were reviewed and tabulated for age, sex, tumor side, tumor size, preoperative and postoperative audiometric and ABR results, intraoperative monitoring results by ABR and CNAP, and surgical complications. RESULTS: Hearing preservation was achieved in seven of nine patients (78%) with absent preoperative ABR, as well as six of seven patients (86%) with tumors less than or equal to 20 mm in greatest dimension. Although intraoperative ABR monitoring was not possible in any of these patients, CNAP monitoring was successful in all. Return of ABR waveforms was observed in four of the six patients (67%) tested from 3 to 22 months postoperatively. Four of the seven patients (57%) enjoyed improvement in hearing class as defined by the guidelines of the American Academy of Otolaryngology-Head and Neck Surgery. CONCLUSIONS: Absent ABR waveforms have not been a negative prognostic sign regarding hearing preservation. CNAP monitoring is possible in these patients and likely helps to minimize iatrogenic cochlear nerve trauma. Patients with no ABR waveforms have hope of hearing preservation and even improvement following acoustic neuroma resection performed utilizing CNAP monitoring and hearing preservation surgical techniques.

Effects of estrogen and tamoxifen on growth of human vestibular schwannomas in the nude mouse.

Vestibular schwannomas have been noted to have increased frequency and aggressivity in female patients, suggesting a possible role of estrogen. This study evaluated the effects of estrogen and tamoxifen on the growth of human vestibular schwannoma tissue implanted in subcutaneous pockets of nude mice. Animals were implanted with 1 of 3 human vestibular schwannomas and observed for 28 days. Mice were then separated into 3 treatment groups: controls, estrogen (receiving 1.7 mg of 17B-estradiol), and estrogen + tamoxifen (receiving 1.7 mg of 17B-estradiol + 10 mg of tamoxifen), and treated for 28 days. Mice treated with estrogen showed increased growth that was statistically significant (P < 0.05) when compared with that of both the controls and the animals treated with estrogen + tamoxifen. Controls and animals treated with estrogen + tamoxifen showed a general trend of decreased volume during the treatment period. These early results support the hypothesis that estrogen modulates the growth of vestibular schwannomas in the nude mouse model and that these effects can be blocked by tamoxifen administration.

Cochlear hook anatomy: evaluation of the spatial relationship of the basal cochlear duct to middle ear landmarks.

The cochlear hook is an important anatomical area for the otologist performing cochlear implants and other otological procedures, who requires knowledge of the basal cochlea. A total of 15 human temporal bones were dissected and the spatial relationship of the hook segment of the cochlear duct to the stapes, round window, cochleariform process and ductus reuniens were evaluated. Inter-individual variability was noted for widths of scala tympani (average width 1.36 +/- 0.25 mm) and scala vestibuli (average width 1.18 +/- 0.18 mm) in the region of typical cochlear implant placement, with the scala vestibuli occasionally being wider than the scala tympani. The cochlear duct was in closest proximity to the stapes at the midportion of the footplate, with an average distance of 1.23 mm at this narrowest width. A fibrous anchor, not previously described in otology literature, was identified securing the most basal end of the cochlear duct. Knowing the spatial relationship of the cochlear duct to the middle and inner ear structures could prevent damage to the basilar membrane in procedures around or involving the basal cochlear, such as cochlear implantation, stapedotomy, or implantable hearing devices.

Auditory disorder in central nervous system miliary tuberculosis: case report.

We evaluated a 28-year-old female with a unilateral hearing loss of unusual pathogenesis, that of central nervous system miliary tuberculosis. Audiologic and otologic findings were consistent with left retrocochlear disorder, characterized by a profound hearing sensitivity loss, absent acoustic reflexes, normal otoacoustic emissions, and the presence of only wave I of the auditory brainstem response. Imaging studies revealed the presence of multiple punctate lesions, one of which was extra-axial and located at the left cerebellopontine angle. The pattern of audiometric test results, particularly the combination of normal otoacoustic emissions and profound hearing sensitivity loss, contributed importantly to the investigative sequence leading to the final diagnosis.

Otologic Wegener's granulomatosis with facial nerve palsy.

Wegener's granulomatosis, characterized by necrotizing granulomas and vasculitis of the respiratory tract and kidney, frequently first presents with otologic symptoms. We report a case of primary otologic Wegener's granulomatosis in a patient who presented with symptoms of acute otomastoiditis and associated facial nerve palsy. The patient subsequently developed neuropathies of various cranial nerves. The patient underwent urgent mastoidectomy with facial nerve decompression. Nonspecific inflammatory disease of the mastoid mucosa delayed the correct diagnosis of Wegener's granulomatosis, which was confirmed by an elevated level of cytoplasmic-pattern antineutrophil cytoplasmic antibody (cANCA). We contrast the specificity of middle ear mucosal disease and cANCA serum levels in the diagnosis of Wegener's granulomatosis.

Acoustic effect of malleus head removal and tensor tympani muscle section on middle ear reconstruction.

In the reconstruction of ears with a missing incus, an incus replacement prosthesis (IRP) is commonly used to connect malleus and stapes. In some cases, it is necessary to resect the malleus head and/or section the tensor tympani muscle (TTM) tendon. The acoustic effects of these maneuvers have not been well studied. We performed experiments in a temporal bone model to measure the effect of these maneuvers on middle ear sound transmission. Measurements of umbo and stapes displacement were made before and after malleus head removal and TTM section plus incus replacement with an IRP. After malleus head removal, there was a peak gain in stapes displacement of 6 dB below 0.5 kHz and 8 dB above 2.5 kHz. TTM section had a similar but lesser effect. A clinical example is described.

Human vestibular schwannoma growth in the nude mouse: evaluation of a modified subcutaneous implantation model.

HYPOTHESIS: Based on the hypothesis that vestibular schwannomas can be successfully implanted and grown in the nude mouse model, an in vivo experiment was designed for subcutaneous implantation of solid vestibular schwannoma tissue. BACKGROUND: Vestibular schwannomas are benign tumors arising from Schwann cells of cranial nerve VIII. Little in vivo research has been carried out with these tumors, due in part to the difficulty to grow cells in culture or maintain tumor in an animal model. Recently, vestibular schwannomas have been implanted in nude mice with moderate success. The current study evaluates a modification of prior techniques in an effort to establish a dependable research model. METHODS: Thirty-six nude mice were implanted with variable-sized vestibular schwannoma tissue from three human subjects. Volumes implanted ranged from 14-170 mm3. Mice were observed for 28 days and individual volumes recalculated. Eleven of the mice were observed for a total of 56 days with volumes re-evaluated, and tumors subsequently were removed for assessment of viability and vascularity. RESULTS: At 28 days, 36 tumors (100%) showed take with 34 tumors (94%) showing macroscopic growth. The 11 tumors observed for 56 days showed a trend of stable or decreased size at 56 days compared with that of the 28-day measurement. Overall growth from time of implantation to measurements at 56 days was noted in 8 (73%) of 11 tumors when measured at the skin and in 10 (91%) of 11 tumors when direct tumor volume was measured. One hundred percent of tumors evaluated microscopically at 56 days was viable. All tumors at the time of removal had significant vascularity with a mean of 70.68% (SD = 23.42) of surface covered with vessels. There were no significant differences in take and growth for the larger tumor specimens compared with those of smaller sizes. CONCLUSION: Human vestibular schwannomas successfully can be implanted and maintained in the subcutaneous pocket of the nude mouse. This in vivo tumor model provides a reliable, accessible base for further research with vestibular schwannomas.

The diagnosis and treatment of central giant cell granuloma.

This report reviews the literature involving the central giant cell granuloma. Diagnosis and treatment is presented. The article reports the case of a child who was initially seen in her general dentist's office, then referred to an oral and maxillofacial surgeon. Differential diagnoses of both benign and malignant lesions related to the central giant cell tumor are discussed.

Traumatic cranial defects reconstructed with the HTR-PMI cranioplastic implant.

Titanium mesh, polymethyl methacrylate application, and autogenous bone grafting have been used to reconstruct traumatic cranial defects, with varying success. A more recent technique utilizing hard tissue replacement-patient matched implants (HTR-PMIs) involves the production of a cranioplastic implant using three-dimensional computed tomography imaging. It has proven less time-consuming and provides an excellent cosmetic result for the patient. The authors present two case reports using this technique to correct traumatic cranial defects. Both patients exhibited satisfactory results and no postoperative complications. The authors believe this relatively new technique represents an advance in the management of large cranial defects.

A double-blind placebo-controlled trial of baclofen in the treatment of tinnitus.

OBJECTIVE: To determine the effectiveness of baclofen in ameliorating tinnitus in adult patients. STUDY DESIGN: Randomized double-blind placebo-controlled trial. SETTING: California Ear Institute at Stanford, California, a tertiary otology/neurotology referral center. PATIENTS: Restricted to adults receiving otologic evaluation at the California Ear Institute at Stanford. Some patients had a primary complaint of tinnitus, whereas others with tinnitus were recruited during treatment for another condition. The study population was felt to be representative of the general population with tinnitus. INTERVENTIONS: Three weeks of baclofen (10 mg orally twice daily for 1 week, 20 mg orally twice daily for the second week, and 30 mg orally twice daily for the third week) or placebo designed to mimic baclofen capsules in route, schedule, appearance, and taste were given to patients. MAIN OUTCOME MEASURES: Tinnitus handicap inventory, pitch and loudness matching, and maskability of tinnitus. RESULTS: Subjective and objective evaluation failed to demonstrate any clinical or statistical advantage of baclofen over placebo. Reports of subjective improvement occurred in only 9.7% of the baclofen versus 3.4% of the placebo groups, a nonsignificant difference. Withdrawal from the baclofen arm of the study occurred in 26% due to side effects, which could be attributed to the medication. CONCLUSIONS: Baclofen is no more effective than placebo in ameliorating tinnitus in adult patients.

Mortality associated with cervicofacial necrotizing fasciitis.

Cervicofacial necrotizing fasciitis is a rare infection but still occurs and carries a mortality rate up to 60%. It is a polymicrobial infection that is characterized by diffuse necrosis of fascial planes and subcutaneous tissues. Diagnosing early stages of cervicofacial necrotizing fasciitis in relationship to other soft tissue infections of odontogenic origin is difficult and leads to less aggressive treatment with resulting increased morbidity and mortality. To prevent this significant mortality and morbidity associated with cervicofacial necrotizing fasciitis early presentation, recognition and treatment by health care provider is essential.