Phosphaturic Mesenchymal Tumor.

Phosphaturic mesenchymal tumors (PMTs) are neoplasms associated with tumor-induced osteomalacia. Patients typically present with pathologic fractures in the setting of chronic hypophosphatemic hyperphosphaturic osteomalacia, as well as gradual muscle weakness, bone pain, and difficulty walking. Because of their rarity and nonspecific symptomatology, phosphaturic mesenchymal tumors often go undiagnosed for years. Even when discovered on imaging, the tumors can be diagnostically challenging for radiologists. Phosphaturic mesenchymal tumors often tend to be small and can be located nearly anywhere in the body, and, therefore, can mimic many other tumors. This case highlights the imaging and pathologic markers of a phosphaturic mesenchymal tumor, often found in a patient with tumor-induced osteomalacia.

Characteristics of electrically evoked potentials in patients with auditory neuropathy/auditory dys-synchrony.

The primary goal of this study was to compare the characteristics of the post-implant evoked potentials with preimplant evoked potentials in patients with auditory neuropathy (AN) or dys-synchrony. AN is typically characterized by sensorineural hearing loss, reduced speech perception, abnormal temporal processing, and unusual patterns of results with various objective audiological tests. In some cases, these patients may be appropriate candidates for a cochlear implant. In this article, we highlight evoked potential findings in two children diagnosed with AN who were provided with multichannel cochlear implants. Preoperative, interoperative and postoperative evoked potential measures show that the restoration of neural synchrony may occur at multiple levels of the auditory pathways in patients with AN when appropriate diagnostic tests, cochlear implantation and rehabilitation are provided.

Cochlear implants in five cases of auditory neuropathy: postoperative findings and progress.

OBJECTIVES: To review our experiences with some of the preoperative and postoperative findings in five children who were diagnosed with auditory neuropathy and were provided with cochlear implants. We describe changes in auditory function, which enabled these children to have significant improvement in their hearing and communication skills. STUDY DESIGN: Pre- and postoperatively, these children received complete medical examinations at Mayo Clinic, including related consultations in audiology, pediatrics, neurology, medical genetics, otolaryngology, psychology, speech pathology, and radiology. METHODS: These children typically had additional medical and audiological examinations at more than one medical center. The hearing assessments of these children included appropriate behavioral audiometric techniques, objective measures of middle ear function, acoustic reflex studies, transient (TOAE) or distortion product (DPOAE) otoacoustic emissions, auditory brainstem responses (ABR), and, in some cases, transtympanic electrocochleography (ECoG). After placement of the internal cochlear implant devices (Nucleus CI24), intraoperatively we measured electrode impedances, visually detected electrical stapedius reflexes (VESR) and neural response telemetry (NRT). These intraoperative objective measures were used to help program the speech processor for each child. Postoperatively, each child has had regular follow-up to assure complete healing of the surgical incision, to assess their general medical conditions, and for speech processor programming. Their hearing and communication skills have been assessed on a regular basis. Postoperatively, we have also repeated electrode impedance measurements, NRT measurements, otoacoustic emissions, and electrical auditory brainstem responses (EABR). We now have 1 year or more follow-up information on the five children. RESULTS: The five children implanted at Mayo Clinic Rochester have not had any postoperative medical or cochlear implant device complications. All of the children have shown significant improvements in their sound detection, speech perception abilities and communication skills. All of the children have shown evidence of good NRT results. All but case D (who was not tested) showed evidence of good postoperative EABR results. Otoacoustic emissions typically remained in the non-operated ear but, as expected, they are now absent in the operated ear. CONCLUSION: Our experiences with cochlear implantation for children diagnosed with auditory neuropathy have been very positive. The five children we have implanted have not had any complications postoperatively, and each child has shown improved listening and communication skills that have enabled each child to take advantage of different communication and educational options.

Long-term follow-up of transtympanic gentamicin for Ménière's syndrome.

OBJECTIVE: Recent studies have shown that transtympanic gentamicin for Ménière's syndrome is effective. Current treatment protocols vary. One concept has been to perform a chemical ablation; the other has been to perform a chemical alteration. Ablation requires multiple injections and is effective in controlling the vertigo, but it is associated with a significant incidence of hearing loss. Chemical alteration uses a minimal dose to reduce vestibular function without affecting cochlear function. STUDY DESIGN: Prospective. SETTING: Tertiary medical center. PATIENTS: Patients had classic unilateral Ménière's syndrome that was unresponsive to medical therapy. INTERVENTION: A single injection of gentamicin is given, and the patient is seen 1 month after injection. If indicated, the patient receives another injection and is reevaluated 1 month later. MAIN OUTCOME MEASURES: Control of vertigo and maintenance of hearing using the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines (1995). RESULTS: Fifty-six patients have documented follow-up for 2 years or more, and 21 have 4 years or more of follow-up. This article presents the 4-year results as outlined by the AAO-HNS guidelines. Vertigo classes A and B were seen in 82% of patients. The patients followed 2 to 4 years had 86% vertigo class A and B results. Those followed 4 years or more show 76% with a vertigo class A or B result. In this study there has been minimal cochlear loss. There was vestibular change clinically, which was documented by electronystagmography. CONCLUSIONS: It appears that a single transtympanic gentamicin injection is effective in controlling the vertigo of Ménière's syndrome. Cochlear impact has been minimal. It is most useful for those patients who have failed medical management and are severely affected but not totally incapacitated by the disease.

Open trial of methotrexate as treatment for autoimmune hearing loss.

OBJECTIVE: To assess the efficacy of low-dose methotrexate (MTX) administered for the treatment of autoimmune hearing loss. METHODS: This was a prospective, 12-month, open-label study of 17 patients with refractory autoimmune hearing loss. All patients had ongoing episodic worsening of hearing in one or both ears prior to enrollment despite traditional medical therapy. The MTX dose was 7.5-25 mg/week. Hearing loss and vertigo were evaluated at baseline and at completion of the study. Hearing improvement was defined as an improvement in pure tone threshold (PT) average of >10 dB or an increase in speech discrimination (SD) of >15%; worsening was defined as a decrease of >10 dB in PT or a decrease of >15% in SD in at least one ear. RESULTS: MTX was well tolerated. Among patients with Meniere's disease, 5 of 9 had improvement or resolution of vertigo. Equilibrium improved in all 3 patients with Cogan's syndrome and improved in 2 out of 3 patients with idiopathic hearing loss and this symptom. According to the parameters defined above, hearing improved in 11 patients (65%), was unchanged in 4 patients (23%), and worsened in 2 patients (12%). CONCLUSION: Long-term low-dose MTX therapy may be a useful therapy for at least some patients who have hearing loss with a presumptively autoimmune-mediated component that is refractory to traditional therapies.

Lesions of the internal auditory canal and cerebellopontine angle in an only hearing ear: is surgery ever advisable?

OBJECTIVE: To define the indications for surgery in lesions of the internal auditory canal (IAC) and cerebellopontine angle (CPA) in an only hearing ear. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Seven patients with lesions of the IAC and CPA who were deaf on the side opposite the lesion. Five patients had vestibular schwannoma (VS), and one each had meningioma and progressive osseous stenosis of the IAC, respectively. The opposite ear was deaf from three different causes: VS (neurofibromatosis type 2 [NF2]), sudden sensorineural hearing loss, idiopathic IAC stenosis. INTERVENTION(S): Middle fossa removal of VS in five, retrosigmoid resection of meningioma in one, and middle fossa IAC osseous decompression in one. MAIN OUTCOME MEASURE: Hearing as measured on pure-tone and speech audiometry. RESULTS: Preoperative hearing was class A in four patients, class B in two, and class C in one. Postoperative hearing was class A in three patients, class B in one, class C in two, and class D in one. CONCLUSIONS: Although the vast majority of neurotologic lesions in an only hearing ear are best managed nonoperatively, in highly selected cases surgical intervention is warranted. Surgical intervention should be considered when one or more of the following circumstances is present: (1) predicted natural history of the disease is relatively rapid loss of the remaining hearing, (2) substantial brainstem compression has evolved (e.g., large acoustic neuroma), and/or (3) operative intervention may result in improvement of hearing or carries relatively low risk of hearing loss (e.g., CPA meningioma).

Is the entire fundus of the internal auditory canal visible during the middle fossa approach for acoustic neuroma?

HYPOTHESIS: To determine the degree to which the fundus of the internal auditory canal (IAC) can be visualized during the middle fossa approach (MFA). BACKGROUND: Conventional wisdom states that the MFA provides excellent access to the IAC from the porus acusticus to the fundus. On the basis of observations derived from a substantial surgical experience, it became obvious that a variable fraction of the fundus lies obscure from the surgeon's line of sight during the MFA because of (1) the overhand of the transverse crest and/or (2) the immobility of the facial nerve at its entry into the fallopian canal. METHODS: Intraoperative measurements were performed in ten cases to determine the typical angle of view to the fundus of the IAC in the MFA. This angle of view was projected onto coronal computed tomography scans of 40 temporal bones. Measurements of the IAC were made to determine the amount of fundus that could not be directly visualized during a MF exposure. RESULTS: On the basis of a surgical line of sight, the fraction of the inferior compartment of the canal that could not be directly visualized because of overhand of the transverse crest ranged from 14% to 34% (median 25%). CONCLUSIONS: Complete resection of IAC tumors involving the fundus via the MFA requires some degree of blind dissection. Specialized tools and techniques are required to minimize the risk of neural injury during this indirect dissection. Inspection of the fundus with either mirror or endoscope is often necessary to exclude the possibility of retained tumor fragments.

Assessment of dysequilibrium after acoustic neuroma removal.

OBJECTIVE: Published data evaluating the rate of dysequilibrium after acoustic neuroma removal are inconsistent. The purpose of this investigation was to determine the incidence and severity of dysequilibrium and quality of life in a group of patients after acoustic neuroma surgery. STUDY DESIGN: The study design was a retrospective chart review and survey that included demographic and medical history questions, the Dizziness Handicap Inventory (DHI), the UCLA Dizziness Questionnaire (UCLA-DQ), and the Health Status Questionnaire (HSQ). SETTING: The study was conducted in a multispecialty tertiary care clinic. PATIENTS: Two hundred thirty-seven subjects who underwent initial surgical removal of an acoustic neuroma between January 1990 and June 1997 were studied. MAIN OUTCOME MEASURES: Correlation of dysequilibrium with age, gender, and tumor size was measured. Survey analysis including DHI, UCLA-DQ, and HSQ scores. RESULTS: Sixty-five percent of patients reported persistent dysequilibrium after surgery. A majority of those with dysequilibrium had DHI, UCLA-DQ, and HSQ scores that suggested minimal impact on the quality of life. The HSQ scores were statistically significantly poorer for the patients with dysequilibrium than for those without dysequilibrium. CONCLUSIONS: Sixty-five percent of patients reported dysequilibrium after acoustic neuroma removal. The quality-of-life impact was mild.

Extradural temporal lobe retraction in the middle fossa approach to the internal auditory canal: biomechanical analysis.

HYPOTHESIS: The middle fossa (MF) approach is undergoing a marked resurgence in vestibular schwannoma surgery as a hearing conservation technique. It is widely recognized that the extradural temporal lobe retractors used in this procedure, despite their cleverness of design, could be improved. METHODS: To identify the characteristics of an ideal MF retractor, a systematic analysis of the safety and functionality of four commonly used retractors (House-Urban, Fisch, Garcia-Ibanez, and UCSF) in a human anatomical model was conducted. Intensity of temporal lobe compression, width of exposure, angle of visualization, obstruction to instrument access, ergonomic convenience of use, and adaptability to other subtemporal procedures (e.g. lesions of Meckel's cave and cavernous sinus) were quantified. RESULTS: Because the intracranial portions of the retractors are similar, the force transmitted to the brain differed little among the four retractors. Numerous differences were noted in the ergonomics of use and versatility of the various designs. CONCLUSIONS: The optimal MF retractor would incorporate the best features of each of the existing systems: the integral suction of the Garcia-Ibanez, the bone contour-following design of the Fisch retractor base, the unobtrusiveness and adaptability of the UCSF, and the three-plane adjustability of the vintage House-Urban. Evolution of an "ideal" MF retractor requires further technical refinements and the development of an experimental model of extradural brain retraction to assess the optimal strategy for obtaining exposure while minimizing the risk for temporal lobe injury.

Preoperative identification of patients at risk of developing persistent dysequilibrium after acoustic neuroma removal.

OBJECTIVE: This study aimed to identify preoperative signs or symptoms that correlate with poor postoperative vestibular compensation after acoustic neuroma removal. STUDY DESIGN: The study design was a retrospective chart review. SETTING: The study was conducted at a tertiary care center. PATIENTS: A total of 210 patients who had acoustic neuromas removed via the retrosigmoid approach from January 1, 1990, to July 1, 1995, participated. MAIN OUTCOME MEASURES: Persistent dysequilibrium for > 3 months after surgery was measured. RESULTS: Age (p = 0.002), gender (p = 0.007), presence of preoperative dysequilibrium (p = 0.005), duration of preoperative dysequilibrium > 3.5 months (p = 0.003), and central findings on electronystagmography ( p < 0.001) were related to poor outcome. CONCLUSIONS: The authors found 31% of patients to have dysequilibrium lasting > 3 months after surgical removal of an acoustic neuroma. Age > 55.5 years, female gender, constant preoperative dysequilibrium present for > 3.5 months, and central findings on electronystagmography were associated with a worse outcome.

Sluder's sphenopalatine ganglion neuralgia--treatment with 88% phenol.

Patients who experience chronic recurring head and face pain present a diagnostic and therapeutic challenge. Treatment options for Sluder's neuralgia, an uncommon cause for recurring head and face pain, are controversial. We reviewed the outcomes of patients who underwent intranasal phenolization of the sphenopalatine ganglion for the treatment of Sluder's neuralgia. Eight patients were treated with intranasal cauterization of the sphenopalatine ganglion between 1990 and 1995. Patients were treated an average of 13 times. Overall, patients experienced a 90% decrease in head and face pain for an average of 9.5 months duration. Interestingly, the patients described recurrent pain as less severe, less frequent, and of shorter duration. Intranasal phenolization of the sphenopalatine ganglion appears to be a safe and effective, although temporary, treatment for patients with Sluder's neuralgia. This article will review the symptomatology, differential diagnosis, and phenolization technique for treatment of Sluder's neuralgia.

Irradiated rib cartilage graft for reconstruction of the tympanic membrane: preliminary results.

OBJECTIVE: To evaluate the advantages, disadvantages, safety, and results in reconstruction of the tympanic membrane using irradiated rib cartilage. STUDY DESIGN: Retrospective chart review. SETTING: A tertiary referral center. PATIENTS: All patients who had > or =6 months follow-up who underwent tympanoplasty or tympanomastoidectomy using irradiated rib cartilage graft at our institution from January 1, 1993 to December 31, 1996. INTERVENTION: Tympanoplasty or tympanomastoidectomy using homologous irradiated rib cartilage as graft material. MAIN OUTCOME MEASURES: Postoperative speech reception thresholds, speech discrimination scores, and air-bone gap were compared with preoperative levels. Complications directly related to irradiated rib cartilage tympanoplasty were sought. RESULTS: Speech reception threshold did not significantly change. Speech discrimination scores were stable or improved in all patients. Postoperative air-bone gap was < or =10 dB in 43.2% of patients and < or =20 dB in 70.3% of patients. There was a 16% complication rate regarding tympanoplasty in general. No complications unique to irradiated rib cartilage occurred. CONCLUSION: Irradiated rib cartilage is an alternative tympanoplasty material that may save operating time, spares patients an added incision, provides results similar to other grafting material, and is safe.

In vitro Characteristics of a Glass Ionomer Cement.

Glass ionomer cements were first described by Wilson and Kent and have been used in dentistry since 1969. It has been recommended for bridging ossicular chain defects, fixation of ossicular chain prosthesis, anchoring of cochlear implants, mastoid obliteration, and repair of tegmen and posterior canal wall defects. The biocompatability and stability of this material over time is vital to its usefulness in neurotologic surgery. The purpose of this study was to assess the stability of a glass ionomer cement in the presence of bacteria and in different pH environments. We demonstrated that bacteria readily adhere to the surface and their presence is associated with accelerated loss of matrix. We found the cement to be susceptible to low pH and to release a visible cloud of debris upon contact with fluid. Calcium concentration in the solution was elevated at all pH levels. Although we are able to demonstrate these findings in vitro the clinical relevance is unclear. There have been several cases of aseptic meningitis possibly due to intracranial release of components of the cement. Until further studies are done use of the cement in contact with cerebral spinal fluid should be avoided. This cement, or a similar material, would be useful in neurotologic surgery but prior to widespread use further testing should be done to assess safety.

Pain after acoustic neuroma surgery.

This article focuses on the incidence, pathophysiology, and management of pain removal of acoustic neuroma. The debate regarding the choice of surgical approach and frequency of headaches is reviewed. The proposed causes of postoperative headaches are discussed. Specific surgical strategies to minimize the risk for developing prolonged postoperative headaches are presented, and medical management options are summarized.

Low-dose intratympanic gentamicin and the treatment of Meniere's disease: preliminary results.

The most disabling symptom for most patients with unilateral Meniere's disease is vertigo. Eradication of the diseased end organ is effective in eliminating the vertigo. Labyrinthectomy remains the "gold standard"; unfortunately, residual hearing is sacrificed to obtain this end. The purpose of this study is to evaluate low-dose intratympanic gentamicin for the control of vertigo and for the preservation of hearing. A single dose of gentamicin (10-80 mg) was injected into the middle ear space of 23 patients with unilateral Meniere's disease as an office procedure. Eighty-four percent of the patients had no episodes of vertigo during the last 6 months of follow-up. Pure tone average and word discrimination scores were unchanged as a group. Ninety-five percent of patients had a hearing loss at 6 and 8 kHz that averaged 7.5 dB. Caloric function was reduced in 93%. Low-dose intratympanic gentamicin is a safe, simple, office procedure that is effective in controlling the definitive vertiginous episodes in most patients with unilateral Meniere's disease. Control of vertigo can be obtained with preservation of hearing.

The anatomy of the lower serratus anterior muscle: a fresh cadaver study.

Forty fresh cadaver dissections were studied to determine variations in the anatomy of the lower portion of the serratus anterior muscle. In all cases, the lower three to five slips of the serratus anterior muscle were supplied by one to three branches from the thoracodorsal artery, the so-called serratus branches. Three vascular patterns were identified: type I with one branch (40 percent), type II with two branches (50 percent), and type III with three branches (10 percent). The mean dimensions of the lower serratus anterior flap were 18.0 x 9.0 cm (range 12.0 x 8.0 cm to 21.0 x 15.0 cm). The mean pedicle length was 11.3 +/- 2.8 cm (range 7.3 to 13.3 cm). A crow's foot landmark has been identified to facilitate flap dissection. This landmark marks the juncture of the long thoracic nerve and the dominant serratus branch. This juncture can be found at the superior border of the sixth or seventh rib. The lower serratus anterior flap is ideal for reconstruction of small to moderate-sized defects because of its flat, broad dimensions and its long vascular pedicle.