Microsurgical management of 53 jugular foramen schwannomas: lessons learned incorporated into a modified grading system

Abstract

A dvAnces in microsurgical techniques and cranial base approaches have allowed access to areas of the brain once considered inaccessible. Despite these advances, however, the microsurgical resection of jugular foramen schwannomas continues to pose a formidable challenge. Fewer than 200 cases of schwannomas arising from the jugular foramen have been reported in the literature, a testament to the rarity of this tumor. 25,29,41,53,59,65,71,74 Experience has shown that the traditional suboccipital and transmastoid approaches do not provide adequate exposure of these lesions. Understanding and utilizing advanced skull base surgery techniques and concepts is essential for adequate resection of these tumors with CN preservation. We review the senior author's experience (T.F.) in the management of 53 jugular foramen schwannomas and propose a modified grading scheme to guide operative planning for these tumors. MethodsWe retrospectively reviewed all cases of jugular foramen schwannomas treated by the senior author Object. Due to the proximity and involvement of critical neurovascular structures, the resection of jugular foramen schwannomas can pose a formidable challenge. The authors review their experience in the microsurgical management of jugular foramen schwannomas and propose a modified grading scale to guide surgical management.Methods. All jugular foramen schwannoma cases treated by the senior author (T.F.) between 1980 and 2004 were retrospectively reviewed. The average age at presentation, surgical approach, tumor characteristics, cranial nerve (CN) deficits, and tumor recurrence rates were assessed. The authors present the following modified grading scale: Type A, intradural tumors; Type B, dumbbell-shaped tumors; and Type C, triple dumbbell tumors with a high cervical extension.Results. The authors treated jugular foramen tumors in 129 patients during the study period. Of these, 53 patients (41%) had jugular foramen schwannomas. The mean patient age was 52 years (range 14-74 years); there were 12 male and 41 female patients. The mean follow-up period was 8.4 years. Patients presented most commonly with deficits of the vagus nerve, followed by vestibular/cochlear nerve and glossopharyngeal nerve deficits. Gross-total resection of the tumor was achieved in 48 patients (90.5%). New postoperative paresis in a previously normal CN was not seen; however, worsening of preoperative CN deficits was frequently noted. The highest incidence occurred with the glossopharyngeal and vagus nerves (30%), with 26% of the deficits being permanent. There were no deaths related to surgery in this series. Three patients (5.7%) experienced tumor recurrence.Conclusions. The microsurgical resection of jugular foramen schwannomas carries a risk of worsening preoperative CN deficits; however, these are often transient. Based on their experience, the authors have formulated a grading scale that predicts the optimal surgical approach to these lesions. Considerable technical training and microneuroanatomical knowledge of the region is requi...

Suprajugular extension of the retrosigmoid approach: microsurgical anatomy

“…2,8,16,31 However, a small residual component inside the upper part of the jugular foramen is often difficult to access via the retrosigmoid approach, even with its transcondylar extension. Some transmastoid or presigmoid approaches, including the infralabyrinthine modification, provide access to tumor in the foramen, but this access may not provide satisfactory exposure of the intracranial part.…”

Triple dumbbell-shaped jugular foramen schwannomas

“…Several grading systems have been developed for jugular foramen schwannomas depending on the site and extent of the tumours (Kaye et al, 1984, Pellet et al, 1988, Bulsara et al, 2008. In Kaye and colleagues' (Kaye et al, 1984) grading system, jugular foramen tumours are divided into intracranial (Type A), intraosseous (Type B, which can include an extension into the posterior fossa), and extracranial (Type C).…”

“…Dumbbell-shaped jugular foramen schwannomas (DSJFSs) with intra and extracranial extension through enlarged jugular foramen are even rarer, and only about 130 such cases have been reported in the literature (Crumley and Wilson, 1984, Kaye et al, 1984, Shearman et al, 1986, Matsushima et al, 1989, Nibu et al, 1993, Samii et al, 1995, Takahashi et al, 1997, Spinnato et al, 1998, Yoo et al, 1999, Carvalho et al, 2000, Cokkeser et al, 2000, Lee et al, 2001, Sarma et al, 2002, Kadri and Al-Mefty, 2004, Mao et al, 2004, Oghalai et al, 2004, Wilson et al, 2005, Sanna et al, 2006, Bakar, 2008, Bulsara et al, 2008, Chibbaro et al, 2009, Cho et al, 2009, Fukuda et al, 2009, Ichimura et al, 2009, Mazzoni, 2009. DSJFS with a high cervical extension was first classified as triple DSJFS by Bulsara and colleagues (Bulsara et al, 2008). Triple DSJFS is a special type of tumour due to its both intracranial-cervical extensions and involvement of multiple disciplines including neurosurgery, head and neck surgery, and neuro-otology; and one-stage, single-discipline, total removal of these often large tumours is not always possible (Crumley and Wilson, 1984, Nibu et al, 1993, Yoo et al, 1999, Mao et al, 2004, Oghalai et al, 2004, Sanna et al, 2006, Cho et al, 2009, Fukuda et al, 2009, Ichimura et al, 2009.…”

Accessory Nerve Schwannoma Extending to the Foramen Magnum and Mimicking Glossopharyngeal Nerve Tumor—A Case and Review of Surgical Techniques

“…It is usually imperative to monitor very vital structures during operation. These intraoperative monitoring consisted of lower CNs, brainstem auditory evoked potentials, somatosensory evoked potentials, motor evoked potentials, and facial nerve monitoring [11].…”

“…Furthermore, Bulsara and associates proposed another scheme which is a modification of the classification system initially proposed by Kaye and colleagues [11] [19] and modified by Pellet and associates [11] [20]. In this scheme (Table 2), the tumors are classified according to only imaging studies to deter- Table 2.…”