Keyhole retrosigmoid approach for large vestibular schwannomas: strategies to improve outcomes

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>There are numerous treatment strategies in the management for large vestibular schwannomas, including resection only, staged resections, resections followed by radiosurgery, and radiosurgery only. Recent evidence has pointed toward maximal resection as being the optimum strategy to prevent tumor recurrence; however, durable tumor control through aggressive resection has been shown to occur at the expense of facial nerve function and to risk other approach-related complications. Through a retrospective analysis of their single-institution series of keyhole neurosurgical approaches for large vestibular schwannomas, the authors aim to report and justify key techniques to maximize tumor resection and reduce surgical morbidity.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>A retrospective chart review was performed at the Centre for Minimally Invasive Neurosurgery. All patients who had undergone a keyhole retrosigmoid approach for the resection of large vestibular schwannomas, defined as having a tumor diameter of ≥ 3.0 cm, were included in this review. Patient demographics, preoperative cranial nerve status, perioperative data, and postoperative follow-up were obtained. A review of the literature for resections of large vestibular schwannomas was also performed. The authors’ institutional data were compared with the historical data from the literature.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Between 2004 and 2017, 45 patients met the inclusion criteria for this retrospective chart review. When compared with findings in a historical cohort in the literature, the authors’ minimally invasive, keyhole retrosigmoid technique for the resection of large vestibular schwannomas achieved higher rates of gross-total or near-total resection (100% vs 83%). Moreover, these results compare favorably with the literature in facial nerve preservation (House-Brackmann I–II) at follow-up after gross-total resections (81% vs 47%, p &lt; 0.001) and near-total resections (88% vs 75%, p = 0.028). There were no approach-related complications in this series.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>It is the experience of the senior author that complete or near-complete resection of large vestibular schwannomas can be successfully achieved via a keyhole approach. In this series of 45 large vestibular schwannomas, a greater extent of resection was achieved while demonstrating high rates of facial nerve preservation and low approach-related and postoperative complications compared with the literature.</jats:p></jats:sec>

Preservation of facial nerve functions during vestibular schwannoma surgery: outcome analysis

“…This was a reason for not trying to drill the meatus for attacking the part of the neoplasm that originated inside it where in all of our patients, stimulation at the region of the internal meatus resulted in a train activity and disappeared after stoppage of procedure. Hadjipanayis et al [19], Gurgel et al [20], Starnoni et al [21], and Hoshide et al [22] also matched our opinion and advised postoperative radiosurgery.…”

Surgical management for large vestibular schwannomas: a systematic review, meta-analysis, and consensus statement on behalf of the EANS skull base section

“…The pooled overall GTR rate was 77% (95% CI 70.6–83.3%) in large series of large VS (Fig. 1 ) [ 2 , 13 , 14 , 17 , 19 , 25 , 26 , 30 , 33 – 35 , 47 , 64 , 66 , 76 , 77 , 88 , 97 , 99 , 100 , 104 , 109 , 119 , 134 , 137 , 138 , 142 , 145 , 147 , 152 , 156 , 160 , 161 , 166 , 169 , 177 , 180 , 181 , 186 – 190 ]. Notably, high-volume hospitals and surgeon caseload have been associated with decreased mortality, decreased postoperative complications and readmission rate, and better oncological and functional outcome [ 7 , 8 ] (Fig.…”

International expert consensus statement about methods and indications for keyhole microneurosurgery from International Society on Minimally Invasive Neurosurgery

“…After the arachnoid membrane is opened sufficiently and the cerebellum is relaxed well, the cerebellar tonsils can be retracted bilaterally, and the inferior cerebellar vermis can be easily elevated upward to expose the whole fourth ventricle region (Level III [36]). Level III [15,24,36,40,43,51] Level III [43] Level III [43,51] Level III [36,40,51] Surgical procedures A 4-cm straight vertical incision is made from 5 mm above the external occipital protuberance in the midline or paramedian for the "paramedian infratentorial supracerebellar keyhole approach" (PISKA). A craniectomy or craniotomy located just inferior to the transverse sinus is carefully performed in keyhole fashion using a high-speed drill.…”