The Anatomically Intact but Electrically Unresponsive Facial Nerve in Vestibular Schwannoma Surgery

Carlson, Matthew L.; Abel, Kathryn M. Van; Schmitt, William R.; Driscoll, Colin L. W.; Neff, Brian A.; Link, Michael J.

doi:10.1227/neu.0b013e318271bce3

Cited by 18 publications

(15 citation statements)

References 21 publications

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“…Notably, current electrophysiological monitoring capabilities fail to predict which patients will be left with "poor" facial function after surgery (House-Brackmann grade IVor worse), which prohibits the use of these tools for intraoperative decision-making regarding neural grafting techniques. 2,27 Minimal data exist regarding the timeline of recovery for patients with preoperative palsy, and the prognosis of facial nerve function in these patients is unknown. An early report by Neely and Neblett 6 in 1983 described three patients with preoperative facial nerve palsy.…”

Section: Discussionmentioning

confidence: 99%

Long-Term Facial Nerve Outcomes after Microsurgical Resection of Vestibular Schwannomas in Patients with Preoperative Facial Nerve Palsy

et al. 2017

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This study aimed at evaluating facial nerve outcomes in vestibular schwannoma patients presenting with preoperative facial nerve palsy. A retrospective review. Single-institution cohort. Overall, 368 consecutive patients underwent vestibular schwannoma resection. Patients with prior microsurgery or radiosurgery were excluded. Incidence, House-Brackmann grade. Of 368 patients, 9 had confirmed preoperative facial nerve dysfunction not caused by prior treatment, for an estimated incidence of 2.4%. Seven of these nine patients had Koos grade 4 tumors. Mean tumor diameter was 3.0 cm (range: 2.1-4.4 cm), and seven of nine tumors were subtotally resected. All nine patients were followed up clinically for ≥ 6 months. Of the six patients with a preoperative House-Brackmann grade of II, two improved to grade I, three were stable, and one patient worsened to grade III. Of the three patients with grade III or worse, all remained stable at last follow-up. Preoperative facial nerve palsy is rare in patients with vestibular schwannoma; it tends to occur in patients with relatively large lesions. Detailed long-term outcomes of facial nerve function after microsurgical resection for these patients have not been reported previously. We followed nine patients and found that eight (89%) of the nine patients had either stable or improved facial nerve outcomes after treatment. Management strategies varied for these patients, including rates of subtotal versus gross-total resection and the use of stereotactic radiosurgery in patients with residual tumor. These results can be used to help counsel patients preoperatively on expected outcomes of facial nerve function after treatment.

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Section: Discussionmentioning

confidence: 99%

Long-Term Facial Nerve Outcomes after Microsurgical Resection of Vestibular Schwannomas in Patients with Preoperative Facial Nerve Palsy

et al. 2017

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“…En nuestra serie de neurinomas acústicos gigantes se pudo conservar la continuidad anató-mica del facial en 10 de los 11 casos operados, sin embargo, de manera similar a lo informado en otras series 36 , de estos solo 7 mostraron una función facial suficiente para conseguir la oclusión ocular completa (House-Brackman i, ii o iii). De manera que, como se ha visto en otras series, la conservación anatómica del facial no se traduce necesariamente en su conservación funcional, pero tampoco la pérdida de la respuesta en los test electrofisiológicos intraoperatorios necesariamente elimina la posibilidad de recuperación funcional 38 . Por lo tanto, si el facial está anatómicamente conservado, es conveniente esperar para su recuperación al menos 12 meses antes plantear cualquier procedimiento de reconstrucción nerviosa.…”

Section: Tratamiento Quirúrgico Abordajes Y Complicacionesunclassified

Tratamiento del neurinoma acústico gigante

Samprón¹,

Altuna²,

Armendáriz³

et al. 2014

Neurocirugía

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“…Another possibility is that, being unaware that the atrophic or hypotrophic intra-arachnoidal segment of the facial nerve on the tumor surface is extremely vulnerable, the surgeons do not try to avoid as efficiently as possible any pinching with their instruments. The use of intra-operative facial nerve monitoring with modern electroprognostic testing strategies is not always capable of reliably predicting poor outcomes (Carlson et al 2012).…”

Section: Discussionmentioning

confidence: 99%

“…Intra-operative factors including degree of tumor adhesion, tumor vascularity, a "splay" of the facial nerve, preservation of its vascular supply (Clarke 1965) during separation from the tumor capsule and thermal lesions have been determined as possible prognostic criteria for recovery or loss of mimic function (Deguine et al 1998;Lalwani et al 1994;Rivas et al 2011;Schaller 2003b) with little success (Carlson et al 2012). This is why, scientists went further and implemented viral reactivation (Gianoli and Kartush 1996), vasogenic edema (Jannetta et al 1977) or surgical fault(s) as possible reasons for the facial nerve injury.…”

Section: Introductionmentioning

confidence: 99%

Nerve crush but not displacement-induced stretch of the intra-arachnoidal facial nerve promotes facial palsy after cerebellopontine angle surgery

et al. 2016

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Little is known about the reasons for occurrence of facial nerve palsy after removal of cerebellopontine angle tumors. Since the intra-arachnoidal portion of the facial nerve is considered to be so vulnerable that even the slightest tension or pinch may result in ruptured axons, we tested whether a graded stretch or controlled crush would affect the postoperative motor performance of the facial (vibrissal) muscle in rats. Thirty Wistar rats, divided into five groups (one with intact controls and four with facial nerve lesions), were used. Under inhalation anesthesia, the occipital squama was opened, the cerebellum gently retracted to the left, and the intra-arachnoidal segment of the right facial nerve exposed. A mechanical displacement of the brainstem with 1 or 3 mm toward the midline or an electromagnet-controlled crush of the facial nerve with a tweezers at a closure velocity of 50 and 100 mm/s was applied. On the next day, whisking motor performance was determined by video-based motion analysis. Even the larger (with 3 mm) mechanical displacement of the brainstem had no harmful effect: The amplitude of the vibrissal whisks was in the normal range of 50°-60°. On the other hand, even the light nerve crush (50 mm/s) injured the facial nerve and resulted in paralyzed vibrissal muscles (amplitude of 10°-15°). We conclude that, contrary to the generally acknowledged assumptions, it is the nerve crush but not the displacement-induced stretching of the intra-arachnoidal facial trunk that promotes facial palsy after cerebellopontine angle surgery in rats.

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The Anatomically Intact but Electrically Unresponsive Facial Nerve in Vestibular Schwannoma Surgery

Abstract: These data demonstrate that even among this extreme subset, modern electroprognostic testing strategies are incapable of reliably predicting poor outcomes. Therefore, if FN continuity is maintained, attempts at same-surgery FN repair should not be pursued.

Cited by 18 publications

References 21 publications

Long-Term Facial Nerve Outcomes after Microsurgical Resection of Vestibular Schwannomas in Patients with Preoperative Facial Nerve Palsy

Long-Term Facial Nerve Outcomes after Microsurgical Resection of Vestibular Schwannomas in Patients with Preoperative Facial Nerve Palsy

Tratamiento del neurinoma acústico gigante

Nerve crush but not displacement-induced stretch of the intra-arachnoidal facial nerve promotes facial palsy after cerebellopontine angle surgery

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