Calhoun D. Cunningham

Postoperative Infection in Cochlear Implant Patients

OBJECTIVE: Recently, the association of meningitis with cochlear implants has raised concern over the safety of these devices. We examined the incidence of all postoperative infections in patients undergoing cochlear implant surgery. STUDY DESIGN AND SETTINGS: A retrospective chart review of all patients undergoing cochlear implants at a private tertiary referral center from 1993 to 2002 was performed. Cochlear implant surgeries in 462 adults and 271 children were reviewed. Patients with evidence of a postoperative infection or infectious complication related to cochlear implantation were identified, and data on patient characteristics, surgery, and treatment outcome were obtained. RESULTS: The overall incidence of postoperative infection in our cochlear implant series was 4.1%. Major infectious complications occurred in 3.0% of cases, and the majority of infections required surgical intervention. A history of chronic ear disease may increase the risk of infectious complications. There were no cases of meningitis. CONCLUSIONS: Cochlear implants remain a safe procedure with a low complication rate. The majority of infections can be managed without removing the implant device. Advances in surgical technique and flap design have decreased the occurrence of wound-related complications. However, identification of risk factors for infection and optimization of treatment regimens will further reduce the complications associated with postoperative infection.

Potassium Recycling Pathways in the Human Cochlea

Objectives/Hypothesis Potential pathways for recycling potassium (K+) used in the maintenance of inner ear electrochemical gradients have been elucidated in animal models. However, little is known about K+ transport in the human cochlea. This study was designed to characterize putative K+ recycling pathways in the human ear and to determine whether observations from animal models can be extrapolated to humans.

Microwave decalcification of human temporal bones.

Objectives/Hypothesis Morphological and immunohistochemical studies of human temporal bones are challenging as a result of difficulties in obtaining reliably fi‐ed specimens and the lengthy time required for decalcification, typically 4 to 7 months. A novel method of processing human temporal bones using a microwave oven to accelerate decalcification is described. This procedure provides a rapid means of decalcifying temporal bones with good preservation of tissue morphology and antigenicity.

Contemporary Surgical Management of Vestibular Schwannomas: Analysis of Complications and Lessons Learned Over the Past Decade

BACKGROUND: Despite advanced microsurgical techniques, more refined instrumentation, and expert team management, there is still a significant incidence of complications in vestibular schwannoma surgery. OBJECTIVE: To analyze complications from the microsurgical treatment of vestibular schwannoma by an expert surgical team and to propose strategies for minimizing such complications. METHODS: Surgical outcomes and complications were evaluated in a consecutive series of 410 unilateral vestibular schwannomas treated from 2000 to 2009. Clinical status and complications were assessed postoperatively (within 7 days) and at the time of follow-up (range, 1-116 months; mean, 32.7 months). RESULTS: Follow-up data were available for 357 of the 410 patients (87.1%). Microsurgical tumor resection was performed through a retrosigmoid approach in 70.7% of cases. Thirty-three patients (8%) had intrameatal tumors and 204 (49.8%) had tumors that were <20 mm. Gross total resection was performed in 306 patients (74.6%). Hearing preservation surgery was attempted in 170 patients with tumors <20 mm, and good hearing was preserved in 74.1%. The main neurological complication was facial palsy (House-Brackmann grade III-VI), observed in 14% of patients (56 cases) postoperatively; however, 59% of them improved during the follow-up period. Other neurological complications were disequilibrium in 6.3%, facial numbness in 2.2%, and lower cranial nerve deficit in 0.5%. Nonneurological complications included cerebrospinal fluid leaks in 7.6%, wound infection in 2.2%, and meningitis in 1.7%. CONCLUSION: Many of these complications are avoidable through further refinement of operative technique, and strategies for avoiding complications are proposed. ABBREVIATIONS: ABR, auditory brainstem response AICA, anterior inferior cerebellar artery CN, cranial nerve CPA, cerebellopontine angle FN, facial nerve GTR, gloss total resection H-B, House-Brackmann HPS, hearing preservation surgery NTR, near-total resection SRT, stereotactic radiation therapy STR, subtotal resection VAFE, vascular, adherent, fibrous, and engulfing VS, vestibular schwannoma

Desmoplastic Fibroma of the Mandible A Case Report

Case of a 4-year-old boy with a desmoplastic fibroma of the mandible. Desmoplastic fibromas are benign fibrous neoplasms which are easily confused with other fibrous tumors. Although benign, they usually display aggressive local tissue extension and frequently recur when treated conservatively. At the present time, wide, local excision appears to be the treatment of choice.

Middle fossa approach for total resection of petrous apex cholesterol granulomas: use of vascularized galeofascial flap preventing recurrence.

BACKGROUND: Cholesterol granulomas (CGs) of the petrous apex (PA) are rare, benign, expanding lesions. Surgical treatment is recommended for patients with symptomatic disease; however, the optimal surgical procedure is still controversial due to high recurrence rates. The main treatment strategy is divided into drainage and complete resection. OBJECTIVE: We advocate radical resection of the lesion by the middle fossa approach and reconstruction with a vascularized galeofascial flap. METHODS: A 10-year retrospective case review of 17 patients undergoing surgical treatment of PA CGs between 2000 and 2010 was undertaken. Operative outcomes and surgical complications were analyzed. In addition, our operative method and the related anatomy are described from cadaveric dissections. RESULTS: All but 1 patient was operated on via a middle fossa approach. Using the middle fossa approach, radical resection of all PA CGs was achieved with obliteration of the cyst cavity using a vascularized flap. Important surrounding structures included the internal auditory canal, cochlea, petrous carotid artery, and abducens nerve. There was 1 death caused by internal carotid artery occlusion. No other major complications or cranial nerve deficits occurred postoperatively. Clinical recurrence occurred in 1 patient (5.9%). CONCLUSION: Our technique of radical resection and reconstruction with a vascularized flap has the advantage of being less invasive with less cosmetic deformity and allows preservation of cranial nerve function with a low recurrence rate. Knowledge of the surgical anatomy and the characteristics of CG is prudent because important neurovascular structures may be exposed behind the CG wall due to bony erosion. ABBREVIATIONS: AE, arcuate eminence CG, cholesterol granuloma GSPN, greater superficial petrosal nerve IAC, internal auditory canal IPS, inferior petrosal sinus PA, petrous apex STA, superficial temporal artery

Choroidal lesions in patients with AIDS.

Seven cases of bilateral, scattered, yellow-white choroidal lesions have been seen in AIDS patients since January 1988. One resulted from presumed extension of cryptococcal meningitis into the optic nerve and choroid. All the remaining six patients had pneumocystis pneumonia at some time during the course of the disease and were receiving aerosolised pentamidine therapy. None died quickly of disseminated Pneumocystis carinii infection, unlike previously reported patients. Mycobacterial infection was also present in five of these six patients. The differential diagnosis of this entity in AIDS patients is discussed.

Preoperative Lumbar Drain Use During Acoustic Neuroma Surgery and Effect on CSF Leak Incidence

Objective: To determine if preoperative lumbar drain (LD) use reduces the incidence of postoperative cerebrospinal fluid (CSF) leak in patients undergoing acoustic neuroma resection. Methods: Retrospective review of 282 patients presenting for acoustic neuroma resection between 2005 and 2014. Results: Two hundred and eighty-two patients had a mean tumor size of 19.1 mm ± 10.2 mm. Twenty-nine (10.3%) patients developed a postoperative CSF leak. Two hundred and twenty patients (78.0%) received a preoperative LD, and 20 (9.1%) developed a CSF leak. Sixty-two (22.0%) patients did not receive a preoperative LD, and 9 (14.5%) developed a CSF leak. No significant difference in CSF leak frequency was observed with use versus no use of a LD (P = .23). Fifteen (5.3%) patients with an LD placed had a complication related to the LD. No significant difference in CSF leak frequency was observed with patient age, neurofibromatosis type-2 diagnosis, tumor size, or sidedness. Conclusions: Postoperative CSF leaks are among the most common complications of acoustic neuroma microsurgery. No formal guidelines exist for elective placement of a preoperative LD to lower the incidence of CSF leaks. Our reported CSF leak incidence with preoperative LD placement is not significantly lower than without LD use, and there is a complication rate associated with LD use.

Liposarcoma of the maxilla.

A clinically appearing, well-encapsulated lipoma was locally excised from the right posterior upper buccal gingival sulcus of a 24-year-old man and diagnosed histologically as pleomorphic liposarcoma. A right maxillectomy with preservation of orbital function was followed by 5,000 rads of planned postoperative radiation therapy. Four months later the tumor recurred outside of the original site, which has been controlled by further radiation and chemotherapy to these areas.

Canalicular reticulum in vestibular hair cells

A membrane limited system referred to as canalicular reticulum (CR) has been demonstrated in the apical cytosol of the cochleas inner and outer hair cells. Similarities between cochlear and vestibular hair cells prompted investigation of the presence of CR in hair cells of the gerbil vestibular labyrinth. A method of fixation with glutaraldehyde followed by an osmium-ferrocyanide mixture demonstrated abundant CR in the apex of both type I and type II hair cells. The CR was closely associated with numerous Golgi zones in the apex of the vestibular hair cells, indicating its genesis from Golgi cisternae. Also preserved in upper cytosol were discrete complexes of mitochondria with granular reticulum. These complexes offered a possible site for generating the membrane in Golgi zones and CR. Single and parallel cisternae of granular reticulum were observed in the basal half of the hair cells together with numerous synaptic-like vesicles. These cisternae with their terminal blebbing and accompanying canaliculi were interpreted as novel structures mediating synaptic vesicle genesis in vestibular hair cells in a manner comparable to that postulated for cochlear inner hair cells.