Robert K. Jackler

A New Standardized Format for Reporting Hearing Outcome in Clinical Trials

The lack of an adequate standardized method for reporting level of hearing function in clinical trials has hampered the ability of investigators to draw comparisons across studies. Variability in data reported and presentation format inhibits meta-analysis and makes it impossible to accumulate the large patient cohorts needed for statistically significant inference. Recognizing its importance to the field and after a widely inclusive discussion, the Hearing Committee of the American Academy of Otolaryngology–Head and Neck Surgery endorsed a new minimal standard for reporting hearing results in clinical trials, consisting of a scattergram relating average pure-tone threshold to word recognition score. Investigators remain free to publish their hearing data in any format they believe is interesting and informative, as long as they include the minimal data set to facilitate interstudy comparability.

Cochlear patency problems in cochlear implantation

Sensory deafness may be associated with partial or total obliteration of the cochlear scalae. Before undertaking cochlear implant surgery, a preoperative assessment of cochlear patency with high‐resolution computed tomography (CT) is indicated. To determine the accuracy of pre‐implant CT, a review of the radiographic and surgical findings in 36 implanted ears was performed. An abnormal CT scan was found to be a reliable predictor of compromised cochlear patency at operation. These findings help the surgeon to select the side most favorable for implantation and to anticipate problems that may be encountered during device insertion. A normal pre‐implant CT scan, however, does not exclude the possibility of compromised cochlear patency. A 46% false negative rate was encountered, presumably because subtle degrees of osseous or fibrous obliteration of the cochlea are beyond the resolution by current generation CT scanners.

A new theory to explain the genesis of petrous apex cholesterol granuloma.

Objective To propose a new hypothesis that attempts to explain the pathogenesis of petrous apex cholesterol granuloma (PA CG). Classic Obstruction-Vacuum Hypothesis PA CGs form when mucosal swelling blocks the circuitous pneumatic pathways to the apical air cells. Trapped gas resorption results in a vacuum that triggers bleeding, and CG forms through anaerobic breakdown of blood products. Problems with the Classic (Obstruction-Vacuum) Hypothesis Impaired ventilation of mucosa-lined pneumatic tracts in the middle ear, mastoid, paranasal sinuses, and lung are very common, but CG is rare. The extraordinary levels of temporal bone pneumatization typically observed in PA CG cases is indicative of excellent ventilation and freedom from inflammatory mucosal disease. Were underpressure due to gas absorption alone sufficient to trigger hemorrhage, CG ought to be frequent in otitis media with effusion. Patients The opposite PA of 13 patients with PA CG compared with 31 highly pneumatic PAs in patients undergoing imagery for nonotologic reasons. Main Outcome Measure The nature of the bony partition, as seen on computed tomography, between the PA air cell system and the adjacent marrow compartment. Results 4 of 13 PAs with CGs on the opposite side showed deficient septation between air cells and marrow, whereas this was not observed in any of the 31 extensively pneumatized normal ears. New Hypothesis (Exposed Marrow) As cellular tracts penetrate the apex during young adulthood, budding mucosa invades and replaces hematopoietic marrow. The bony interface becomes deficient, with coaptation of richly vascular marrow and the mucosal air cell lining. Hemorrhage from the exposed marrow coagulates within the mucosal cells and occludes outflow pathways. Sustained hemorrhage from exposed marrow elements provides the engine responsible for the progressive cyst expansion. As the cyst expands, bone erosion increases the surface area of exposed marrow along the cyst wall. This exposed marrow theory explains the unique proclivity of the healthy and well-pneumatized PA to form a CG.

The Fate of the Tumor Remnant after Less-than-Complete Acoustic Neuroma Resection

OBJECTIVES: We sought to determine the recurrence rate after near-total and subtotal resection of acoustic neuroma. STUDY DESIGN, SETTING, AND PATIENTS: We conducted a retrospective chart review of a total of 79 patients: 50 with near-total resections (remnant ≤ 25 mm 2 and ≤ 2 mm thick) and 29 with subtotal resections (any larger remnant). Surgical approach included 5 middle fossa, 17 retrosigmoid, and 57 translabyrinthine. MAIN OUTCOME MEASURES: Recurrence was defined as documented tumor growth by serial imaging or the recommendation for further treatment after a single scan. No recurrence was defined as no visible tumor on imaging for a minimum follow-up time of 3 years or tumor remnants that remained unchanged on serial scans (mean, 5-year follow-up). RESULTS: Fifty-two patients were included in the study group. Recurrences were seen in 1 (3%) of 33 patients who had a near-total resection compared with 6 (32%) of 19 patients who had a subtotal resection. After adjustment for follow-up time and large tumor size, the odds ratio for recurrence was 12 times larger for subtotal than for near-total resections (P = 0.033). All recurrences were seen following the translabyrinthine approach in the mid-cerebellopontine angle. None were encountered in the internal auditory canal. The mean time interval from surgery to the detection of a recurrence was 3 years (range, 1 to 5 years). CONCLUSIONS: The recurrence rate when performing a near-total resection is low but is substantially higher with a subtotal resection. Recurrences can be detected within the first 5 postoperative years. We recommend near-total resection in any patient if needed to preserve neural integrity. Subtotal resection is best avoided whenever possible; however, adjunctive treatment with stereotactic radiotherapy may be considered.

Cerebrospinal fluid leak after acoustic neuroma surgery: a comparison of the translabyrinthine, middle fossa, and retrosigmoid approaches.

Objective To determine whether the choice of surgical approach affects the rate of postoperative cerebrospinal fluid leakage in patients who have undergone surgical resection of acoustic neuroma. Study Design Retrospective chart review. Setting Tertiary referral center. Patients Three hundred patients who underwent surgery for acoustic neuromas were selected by consecutive medical record number until 100 resections via each surgical approach (translabyrinthine, middle fossa, and retrosigmoid) had been gathered. Main Outcome Measures Surgical approach used, cerebrospinal fluid leak incidence, tumor size, patient age. Results Postoperative cerebrospinal fluid leak of any severity was observed in 13% of translabyrinthine, 10% of middle fossa, and 10% of retrosigmoid patients. These difference in the rate of cerebrospinal fluid leakage were not statistically significant (p = 0.82). The majority of leaks were managed conservatively with fluid and activity restriction, often accompanied by a period of lumbar subarachnoid drainage. There was a need to return to the operating room for a definitive procedure in 4% of translabyrinthine, 2% of middle fossa, and 3% retrosigmoid patients; again not statistically different among the approaches (p = 0.43). Tumor size was not correlated with cerebrospinal fluid leak rate (p = 0.13). Patient age, for patients older than 50 years, was suggestive of increased odds of cerebrospinal fluid leak (p = 0.06). Conclusion Neither surgical approach nor tumor size affects the rate of postoperative cerebrospinal fluid leakage or the necessity of managing a leak with a return to the operating room. Cerebrospinal fluid leakage rates have remained stable in recent decades despite numerous innovative attempts to improve dural closure, seal transected air cell tracts, and occlude anatomic pathways. The finding that leak rates were similar among three dissimilar surgical techniques suggests that factors other than techniques of wound closure, such as transient postoperative rises in cerebrospinal fluid pressure, may be responsible for these recalcitrant cases.

Neurofibromatosis 2, radiosurgery and malignant nervous system tumours.

SirNeurofibromatosis 2 (NF2) is a rare (1:40 000) autosomal domi-nant disease that is caused by mutations of the NF2tumoursuppressor gene. NF2 is characterized by benign nervous systemtumours such as vestibular schwannomas (VSs), intracranialmeningiomas and spinal tumours. Kondziolka et al (1998)reported the outcomes of radiosurgery for unilateral sporadic VSs,but NF2 patients were excluded and follow-up was limited. Theconsequences of radiosurgery for histologically benign NF2tumours merit study due to the mutagenic potential of ionizingradiation. Somatic mutation could contribute to the transformationor acceleration of existing tumours, and to the development ofsecondary tumours, because NF2 patients have an inactivatedgerm-line NF2allele. Ionizing radiation is known to have sucheffects in hereditary retinoblastoma (Wong et al, 1997). Weconducted this study because the prevalence of, and risk factorsfor, malignant nervous system tumours in NF2 are unknown.We surveyed genetics, otolaryngology and neurology/neuro-surgery centres in North America and Europe with a total of 1348NF2 patients. There were nine malignant nervous system tumoursin the estimated 1242 NF2 patients who did not have previousradiosurgery. This prevalence of 725 per 10

Removal of jugular foramen tumors: The fallopian bridge technique

Despite recent advances in neuroradiographic and electrophysiologic assessment, the surgical extirpation of lesions of the bony skull base remains challenging. Moreover, as surgeons have gained experience in removing tumors from the irregular osteologic confines of the skull base, attention has been directed toward preservation of vital neural and vascular structures traversing the operative field. This report describes the creation of a fallopian bridge with preservation of the facial nerve in removing tumors that arise within or juxtaposed to the jugular fossa. Thirty-five patients are reported herein with analysis of pathology, surgical approach, and outcome. An algorithm for use of the fallopian bridge, as opposed to facial nerve mobilization and rerouting, is presented with particular emphasis on limitation of this selective procedure.

Enlargement of the Cochlear Aqueduct: Fact or Fiction?:

Enlargement of the cochlear aqueduct (CA) is often mentioned in the otologic literature, usually in its purported association with sensory hearing loss, stapes gusher, and transotic cerebrospinal fluid leak. In CT scans of 100 ears, the diameter of the CA medial aperture was found to be highly variable, ranging from 0 to 11 mm, with a mean of 4.5 mm. In contrast, the otic capsule segment was very narrow in every case. It could be visualized in only 56% of cases, none of which exceeded 2 mm in diameter. Several published reports of supposed CA enlargement presented images of a dilated medial aperture that was well within the range of normal variability according to the present study. In a thorough review of the literature on radiology of the CA, we were unable to find a single published image that convincingly demonstrated enlargement of the otic capsule portion. As radiographic CA enlargement has not been convincingly reported to date, it appears to be an exceedingly rare or perhaps even nonexistent malformation. It is important to recognize than even a radiographically normal CA may be hyperpatent. It is theoretically possible for increased fluid flow to result from either deficiencies in intraluminal membrane baffles or subtle canal enlargement beneath the resolution limits of CT scanning. However, as fluid flow through a tube is regulated by its narrowest point, It is extremely improbable that stapes gusher, transotic CSF leak, and vigorous perilymphatic fistula are generated by the CA when CT scans show any portion of it to be very narrow. A substantial body of evidence points to a deficient partition between the internal auditory canal and inner ear as causative in such cases. We propose that the criteria for the diagnosis of CA enlargement on high-resolution CT scan be a diameter exceeding 2 mm throughout its course from the posterior fossa to the vestibule.

The value of enhanced magnetic resonance imaging in the evaluation of endocochlear disease.

Background Gadolinium‐enhanced magnetic resonance imaging (GdMRI) is routinely used in the evaluation and management of suspected retrocochlear pathology such as vestibular schwannoma. However, its value in the evaluation and diagnosis of cochlear pathology associated with sensorineural hearing loss (SNHL) has been less clear.

Repair of Chronic Tympanic Membrane Perforations Using Epidermal Growth Factor

Perforation of the tympanic membrane (TM) is a frequent cause of conductive hearing loss. Persistent TM perforations often require surgical repair with an autologous tissue graft to restore hearing and prevent recurrent infection. While highly efficacious, this method of closure requires a relatively complex and expensive microsurgical procedure. We have recently developed a chronic TM perforation model in the chinchilla for use in the exploration of novel methods of TM repair.