Tag: hearing

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Matched Comparison of Hearing Outcomes in Patients With Vestibular Schwannoma Treated With Stereotactic Radiosurgery or Observation

Neurosurgery 91:641–647, 2022

Previous studies comparing hearing outcomes in patients managed with stereotactic radiosurgery (SRS) and a watch-and-wait strategy were limited by small sample sizes that prevented controlling for potential confounders, including initial hearing status, tumor size, and age.

OBJECTIVE: To compare hearing outcomes for patients with vestibular schwannomas (VS) managed with observation and SRS while controlling for confounders with propensity score matching.

METHODS: Propensity score matching was used to compare 198 patients with unilateral VS with initial serviceable hearing (99 treated with SRS and 99 managed with observation alone) and 116 with initial class A hearing (58 managed with SRS and 58 with observation), matched by initial hearing status, tumor volume, age, and sex. Kaplan–Meier survival methods were used to compare risk of losing class A and serviceable hearing.

RESULTS: Between patients with VS managed with SRS or observation alone, there was no significant difference in loss of class A hearing (median time 27.2 months, 95% CI 16.843.4, and 29.2 months, 95% CI 20.4-62.5, P = .88) or serviceable hearing (median time 37.7 months, 95% CI 25.7-58.4, and 48.8 months, 95% CI 38.4-86.3, P = .18). For SRS patients, increasing mean cochlear dose was not related to loss of class A hearing (hazard ratio 1.3, P = .17) but was associated with increasing risk of serviceable hearing loss (hazard ratio of 1.5 per increase in Gy, P = .017).

CONCLUSION: When controlling for potential confounders, there was no significant difference in loss of class A or serviceable hearing between patients managed with SRS or with observation alone.

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Long-Term Hearing Outcomes Following Stereotactic Radiosurgery in Vestibular Schwannoma Patients

Neurosurgery, Volume 85, (4), October 2019, 550–559

An understanding of the hearing outcomes is needed for treatment counseling for patients with vestibular schwannomas (VS).

OBJECTIVE: To determine long-term hearing results following stereotactic radiosurgery (SRS) for VS and identify any influential variables.

METHODS: Tertiary hospital retrospective cohort.

RESULTS: There were 579 tumors (576 patients) treated with SRS. Eighty-two percent (473) of tumors had ≥1 yr and 59% (344 ≥3 yr follow-up. In the 244 tumor ears, with measurable hearing before SRS who were followed ≥1 yr, 14% (31) had improved hearing, 13% (29) unchanged hearing, and 74% (158) had worsened hearing. In 175 patients with ≥3 yr followup and who had measurable hearing pretreatment, 6% (11 ears) improved hearing, 31% (54 ears) unchanged hearing, and 63% (110 ears) had worsened hearing. Patients with tumors with larger target volumes (P = 0.040) and with neurofibromatosis type 2 (NF2; P = 0.017) were associated with poorer hearing (P = 0.040). Patients with word recognition scores (WRS) of 50% or poorer had tumors with a larger volume (P = 0.0002), larger linear size (P=0.032),andNF2(P=0.045).TraditionallyreportedhearingoutcomesusingtheGardner RobertsonmaintenanceofPTA ≤50dborWRS≥50%were48%at3yr,whichoverestimates hearing outcomes compared to the above reporting standards.

CONCLUSION: Hearing declines over time in VS treated with SRS in a high proportion of cases. The frequency and magnitude of long-term hearing decline following SRS argues against prophylactic radiation for small tumors in hearing ears with undetermined growth behavior.

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Cochlear line: a novel landmark for hearing preservation using the anterior petrosal approach

Cochlear line- a novel landmark for hearing preservation using the anterior petrosal approach

J Neurosurg 123:9–13, 2015

The goal of this study was to develop a practical landmark for the safe and easy identification of the cochlea when performing anterior petrosectomy based on cadaver dissection results.

Methods The cochlear line was defined as the line drawn from the crossing point between the greater superficial petrosal nerve (GSPN) and the petrous internal carotid artery to the line drawn over the apex of the superior circumference of the dura of the internal auditory canal at a right angle. The validity of the cochlear line marking the anteromedial perimeter of the cochlea at the angle of the GSPN and the internal acoustic canal as a practical landmark were evaluated using 5 cadaver heads.

Results The mean distance (± SD) measured from the cochlear line to the margin of the cochlear cavity was 2.25 ± 0.51 mm (range 1.50–3.00 mm).

Conclusions Anterior petrosectomy can be performed more efficiently by using the cochlear line as a key landmark to preserve the cochlea.

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Management of large vestibular schwannoma. Part II. Primary Gamma Knife surgery: radiological and clinical aspects

J Neurosurg 115:885–893, 2011.DOI: 10.3171/2011.6.JNS101963

In large vestibular schwannomas (VSs), microsurgery is the main treatment option. A wait-and-scan policy or radiosurgery are generally not recommended given concerns of further lesion growth or increased mass effect due to transient swelling. Note, however, that some patients do not present with symptomatic mass effect or may still have serviceable hearing. Moreover, others may be old, suffer from severe comorbidity, or refuse any surgery. In this study the authors report the results in patients with large, growing VSs primarily treated with Gamma Knife surgery (GKS), with special attention to volumetric growth, control rate, and symptoms.

Methods. The authors retrospectively analyzed 33 consecutive patients who underwent GKS for large, growing VSs, which were defined as > 6 cm3 and at least indenting the brainstem. Patients with neurofibromatosis Type 2 were excluded from analysis, as were patients who had undergone previous treatment. Volume measurements were performed on contrast-enhanced T1-weighted MR images at the time of GKS and during follow-up. Medical charts were analyzed for clinical symptoms.

Results. Radiological growth control was achieved in 88% of cases, clinical control (that is, no need for further treatment) in 79% of cases. The median follow-up was 30 months, and the mean VS volume was 8.8 cm3 (range 6.1–17.7 cm3). No major complications occurred, although ventriculoperitoneal shunts were placed in 2 patients. The preservation of serviceable hearing and facial and trigeminal nerve function was achieved in 58%, 91%, and 86% of patients, respectively, with any facial and trigeminal neuropathy being transient. In 92% of the patients presenting with trigeminal hypesthesia before GKS, the condition resolved during follow-up. No patient- or VS-related feature was correlated with growth.

Conclusions. Primary GKS for large VSs leads to acceptable radiological growth rates and clinical control rates, with the chance of hearing preservation. Although a higher incidence of clinical control failure and postradiosurgical morbidity is noted, as compared with that for smaller VSs, primary radiosurgery is suitable for a selected group of patients. The absence of symptomatology due to mass effect on the brainstem or cerebellum is essential, as are close clinical and radiological follow-ups, because there is little reserve for growth or swelling.

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Functional outcome after complete surgical removal of giant vestibular schwannomas

J Neurosurg 112:860–867, 2010. (DOI: 10.3171/2009.7.JNS0989)
The authors evaluated the outcome of radical surgery in a consecutive series of patients with giant vestibular schwannomas (VSs).
Methods. Fifty patients with VSs > 4.0 cm in maximal extrameatal diameter were included in this retrospective study (Group A). The group was compared with a matched group of 167 patients with VSs < 3.9 cm (Group B). In all cases the retrosigmoid approach was used. Outcome measures included completeness of tumor removal, facial nerve function, hearing, and the surgery-related complication rate.
Results. The mean tumor size in Group A was 4.4 cm and that in Group B was 2.3 cm. Total removal was achieved in all Group A patients and in 97.6% of Group B patients. The anatomical integrity of the facial nerve was preserved in 92% in Group A and in 98.8% in Group B. At last follow-up 75% of the patients with giant VSs had excellent or good facial nerve function, 19% had fair function, and 6% had poor function. In 33% of patients (3 cases) with good preoperative hearing level, it was preserved. Newly developed lower cranial nerve dysfunction occurred in 3 patients but proved to be temporary in 2 of them. A CSF leak developed in 6% of those who not previously undergone surgery. Compared with Group B, a significant difference was found only in the rates of the following parameters: excellent facial nerve function, useful and good hearing, lower cranial nerve dysfunction, and blood collection (p < 0.05). The perioperative mortality rate in both groups was 0%.
Conclusions. In patients with a giant VS, total tumor removal can be achieved via the retrosigmoid approach with a 0% mortality rate and low morbidity rate, especially with regards to facial nerve function. In selected cases even hearing preservation is possible. Tumor size significantly correlates with postoperative outcome.

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