Reversible cochleo-vestibular deficits in two cases of jugular foramen tumor after surgery

Features of postoperative hearing function changes in patients with cerebellopontine angle and intratemporal tumors other than vestibular schwannomas

OBJECTIVE

Tumors around the cerebellopontine angle (CPA) and temporal bone can potentially affect hearing function. In patients with such tumors other than vestibular schwannomas (VSs), auditory tests were investigated before and after surgery to characterize the auditory effect of each tumor and to determine prognostic factors.

METHODS

A total of 378 patients were retrospectively evaluated for hearing functions before and after surgery. These 378 patients included 168 with CPA meningioma, 40 with trigeminal schwannoma (TS), 55 with facial nerve schwannoma (FNS), 64 with jugular foramen schwannoma (JFS), and 51 with CPA epidermoid cyst (EPD).

RESULTS

Preoperative hearing loss was observed in 124 (33%) of the 378 patients. Of these 124 patients, 38 (31%) experienced postoperative hearing improvement. Postoperative hearing deterioration occurred in 67 (18%) of the 378 patients. The prognostic factors for postoperative hearing improvement were younger age and the retrocochlear type of preoperative hearing disturbance. Tumor extension into the internal auditory canal was correlated with preoperative hearing loss and postoperative hearing deterioration. Preoperative hearing loss was observed in patients with FNS (51%), JFS (42%), and MGM (37%), and postoperative hearing improvement was observed in patients with JFS (41%), MGM (31%), and FNS (21%). Postoperative hearing deterioration was observed in patients with FNS (27%), MGM (23%), and EPD (16%).

CONCLUSIONS

According to the results of this study in patients with CPA and intratemporal tumors other than VS, preoperative retrocochlear hearing disturbance was found to be a prognostic factor for hearing improvement after surgery. Among the tumor types, JFS and MGM had a particularly favorable hearing prognosis. The translabyrinthine approach and cochlear nerve section should be avoided for these tumors, regardless of the patient's preoperative hearing level.

Intraoperative Monitoring of Auditory Function During Lateral Skull Base Surgery

OBJECTIVE

We present a unique case of a patient with a jugular foramen tumor with serviceable hearing. This study discusses the audiometric results and intraoperative electrocochleographic (ECochG) findings recorded during tumor removal to illustrate the potential utility of this technique in skull base surgery.

PATIENTS

A 22-year-old female patient presented with a jugular foramen schwannoma and associated symptoms of right-sided otalgia, mild hearing loss, and blurry vision.

INTERVENTIONS

Intraoperative ECochG responses during an infratemporal fossa approach: click and tone burst (1, 2, 4 kHz) stimuli were used and presented at 90 dB nHL.

MAIN OUTCOME MEASURES

Intraoperative ECochG testing using frequency-specific tone bursts and clicks before and after tumor resection.

RESULTS

The compound action potential magnitudes, cochlear microphonic, and summation potential were recorded pre- and post-tumor removal. For statistical analysis, a paired t test with significance set at p < 0.05 was used. The compound action potential magnitudes increased at all test frequencies (p < 0.01) while the summation potential and cochlear microphonic remained relatively stable (p > 0.05). Audiometric testing demonstrated an improvement of the preoperative mild right-sided hearing loss after tumor resection (pure-tone average for 0.5, 1, 2, and 4 kHz of 30 dB HL preoperation and 7.5 dB HL after tumor resection).

CONCLUSIONS

Intraoperative ECochG may allow for real-time monitoring during complex skull base surgery.

Pathophysiology of sensorineural hearing loss in jugular foramen paraganglioma

OBJECTIVES/HYPOTHESIS

Pathologic involvement of the inferior cochlear vein is a mechanism of sensorineural hearing loss in patients with jugular foramen paraganglioma.

STUDY DESIGN

Retrospective case-control study.

METHODS

The presenting audiograms, magnetic resonance imaging, and computed tomography were reviewed in 46 subjects with jugular foramen paragangliomas. Four-frequency bone conduction average was compared between the tumor and nontumor ears in each subject to establish the presence of sensorineural hearing loss. Imaging findings for each subject were recorded. Univariate and multivariate statistical analyses were performed to determine which radiographic features were associated with sensorineural hearing loss. Hearing data were analyzed as a continuous variable and as a categorical variable.

RESULTS

Twenty subjects (43.4%) had a bone-conduction pure-tone asymmetry of greater than 15 dB. Inferior cochlear vein involvement was identified in 19 of the 20 (95%) subjects with sensorineural hearing loss. Inferior cochlear vein involvement was found to be a statistically significant predictor of sensorineural hearing loss using univariate and multivariate analyses. Other imaging findings that were statistically significant predictors of sensorineural hearing loss include Glasscock-Jackson stage, Fisch-Mattox stage, hypoglossal canal involvement, jugulo-carotid spin erosion, and petrous carotid canal erosion.

CONCLUSIONS

Involvement of the inferior cochlear vein appears to be a plausible mechanism for sensorineural hearing loss in patients with jugular foramen paraganglioma.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:67-75, 2019.

Severe progressive sensorineural hearing loss improved after removal of large jugular foramen schwannoma

We report a very rare case of hearing improvement after removal of the intracranial part of a jugular foramen schwannoma (JFS) presenting with chronic and severe progressive sensorineural hearing loss (SNHL). The patient presented with progressive hearing impairment in his right ear, lasting 2 years. The patient's pure tone audiogram revealed severe SNHL. His speech discrimination score (SDS) was 0%. Auditory-evoked brain responses (ABRs) comprised only I waves following 30-100dB stimulation, although distortion-product otoacoustic emissions (DPOAEs) had good responses. These test results indicated that his hearing impairment was retrocochlear SNHL. Magnetic resonance imaging revealed within the right jugular foramen a large intracranial-extracranial tumor that compressed the brainstem. The intracranial part of the tumor was resected through retrosigmoidal craniotomy, and the tumor was pathologically diagnosed as a schwannoma. Several months after the operation, the patient's auditory thresholds improved to a level consistent with mild SNHL, ABR V waves emerged following 60-90dB stimulation, and SDS improved significantly to 95%. This case demonstrates that hearing improvement can be achieved after surgery for JFS presenting with severe and chronic progressive SNHL, and that good DPOAE responses and the presence of ABR I waves may be predictors of postoperative hearing recovery in JFS.