Muscular-stage Dissection during Far Lateral Approach and Its Transcondylar Extension

Abstract

Background The far lateral approach includes exposure of the C1 transverse process, vertebral artery, posterior arch of the atlas, and occipital condyle. We designed a method for systematic muscular-stage dissection and present our experience with this approach.

Operative Methods We used a horseshoe scalp flap that was reflected downward and medially. The lateral muscle layers were separated layer to layer to expose the suboccipital triangle. The medial muscle layers were separated in the midline and reflected in a single layer. At this stage, the midline of the C1 process and the foramen magnum were identified. The rectus capitis posterior major muscle was reflected to expose the posterior arch of the atlas. The C1 transverse process and vertebral artery were identified by reflection of the superior oblique muscle. The occipital condyle was separated accordingly.

Results We used this method of muscular dissection in 10 patients (foramen magnum meningioma, n = 5; hypoglossal schwannoma, n = 2; others, n = 3). Systematic muscular-stage dissection facilitates identification of the anatomical landmarks with no vertebral artery injury. Gross total removal was obtained in all 9 patients with complex tumors. The patient with vertebral artery dissection successfully underwent proximal clipping.

Conclusion Our muscular-stage dissection could contribute to safe and effective surgery for the far lateral approach.

Keywords

far lateral - skull base - surgical approach - muscular dissection

• References

• 1 Heros RC. Lateral suboccipital approach for vertebral and vertebrobasilar artery lesions. J Neurosurg 1986; 64 (04) 559-562
• 2 Sen CN, Sekhar LN. An extreme lateral approach to intradural lesions of the cervical spine and foramen magnum. Neurosurgery 1990; 27 (02) 197-204
• 3 Bertalanffy H, Seeger W. The dorsolateral, suboccipital, transcondylar approach to the lower clivus and anterior portion of the craniocervical junction. Neurosurgery 1991; 29 (06) 815-821
• 4 Wen HT, Rhoton Jr AL, Katsuta T, de Oliveira E. Microsurgical anatomy of the transcondylar, supracondylar, and paracondylar extensions of the far-lateral approach. J Neurosurg 1997; 87 (04) 555-585
• 5 Rhoton Jr AL. The far-lateral approach and its transcondylar, supracondylar, and paracondylar extensions. Neurosurgery 2000; 47 (3, Suppl): S195-S209
• 6 Matsushima T, Natori Y, Katsuta T, Ikezaki K, Fukui M, Rhoton Jr AL. Microsurgical anatomy for lateral approaches to the foramen magnum with special reference to transcondylar fossa (supracondylar transjugular tubercle) approach. Skull Base Surg 1998; 8 (03) 119-125
• 7 Wanibuchi M, Fukushima T, Zenga F, Friedman AH. Simple identification of the third segment of the extracranial vertebral artery by extreme lateral inferior transcondylar-transtubercular exposure (ELITE). Acta Neurochir (Wien) 2009; 151 (11) 1499-1503
• 8 Lau T, Reintjes S, Olivera R, van Loveren HR, Agazzi S. C-shaped incision for far-lateral suboccipital approach: Anatomical study and clinical correlation. J Neurol Surg B Skull Base 2015; 76 (02) 117-121