Tag: far-lateral approach

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History and evolution of the far‑lateral approach in neurosurgery

Acta Neurochirurgica (2026) 168:122

This review chronicles the development and technical refinement of the far‑lateral approach (FLA) for accessing the foramen magnum, lower clivus, and craniovertebral junction, tracing its origins from lateral suboccipital exposures to contemporary transcondylar, supracondylar, paracondylar, and extreme lateral transodontoid variants. It summarizes modifications in skin incisions, bony resection strategies, VA management, positioning, and closure techniques that improved exposure while minimizing brain retraction and craniovertebral morbidity.

The article evaluates clinical outcomes, biomechanical data, and technological integrations—endoscopic assistance, neuronavigation, and neuromonitoring—emphasizing a tailored, pathology-driven philosophy: remove only the bone necessary, mobilize the vertebral artery judiciously, and consider occipitocervical fusion when stability thresholds are exceeded to balance maximal resection with minimal long‑term instability and CSF complications.

Purpose: Provides a more anterior, tangential corridor to the foramen magnum/lower clivus/CVJ for ventrolateral or anterior brainstem pathology, reducing the need for brainstem/cerebellar retraction compared with older midline posterior and transoral routes.

Origins: Evolved from posterolateral aneurysm surgery—early unilateral suboccipital routes in the 1970s, with the first detailed “lateral suboccipital” (far-lateral) description by Heros in 1986 to reach distal vertebral and basilar trunk aneurysms by extending bone removal to the lateral foramen magnum rim.

Key bone-work concept: The major exposure-expanding step is selective occipital condyle drilling (transcondylar variant), typically about one-third to one-half to improve the angle of attack while aiming to preserve craniocervical stability; complete condyle removal is rare and generally prompts fusion.

Modular variants: The approach is used as adjustable “modules,” most notably transcondylar, supracondylar (jugular tubercle drilling), and paracondylar extensions, chosen based on lesion location and direction of extension.

Soft-tissue refinements: Incisions shifted from simple linear cuts to more tailored curvilinear/hockey-stick/C-shaped designs with larger musculocutaneous flaps to improve exposure, enable layered closure, and reduce wound/CSF-leak complications.

Positioning evolution: Use moved away from sitting (air embolism risk) toward lateral/modified park-bench positioning to leverage gravity-assisted relaxation and minimize fixed retraction.

Neurovascular strategy: Standardization of extradural vertebral artery (V3/V4) exposure and mobilization (when needed) improved proximal control and widened the corridor, turning the artery from an obstacle into a structure that can be safely managed to expand working space.

Modern extensions & technology: Continued refinement includes endoscope-assisted visualization, neuronavigation, and neuromonitoring; an extreme extension (ELTO) adds aggressive bony removal (including odontoid/C1 elements) for midline-crossing lesions but carries high instability risk, so occipitocervical fusion is typically performed.

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The Far-Lateral Approach and Its Variants

Operative Neurosurgery 29:740–745, 2025

This technical report details the far‑lateral craniotomy and its variants for accessing ventral and ventrolateral craniovertebral pathologies, emphasizing indications, anatomical considerations, and operative steps. It outlines positioning, incision choices, bone work including condylar modifications, dural handling, and strategies to protect the vertebral artery and lower cranial nerves.

The article highlights advantages, limitations, and common pitfalls—such as occipitocervical instability with extensive condylectomy, hypoglossal canal risk, and CSF leak prevention—and supplements the text with high‑quality dissections and a 4K instructional video aimed at trainees and early‑career neurosurgeons.

 

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Approaches to the Middle Cerebellar Peduncle for Resection of Pontine Cavernomas:

Operative Neurosurgery 26:468, 2024

INDICATIONS: CORRIDOR AND LIMITS OF EXPOSURE: The expanded retrosigmoid approach with splitting of the horizontal cerebellar fissure provides a more direct and shorter route for central and dorsolateral pontine lesions while minimizing retraction of tracts, nuclei, and cerebellum.1-4

ANATOMIC ESSENTIALS: NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: The middle cerebellar peduncle is partially covered by the petrosal surface of the cerebellum. The horizontal cerebellar fissure (petrosal fissure) divides the petrosal surface of the cerebellar hemisphere into superior and inferior parts. Splitting the petrosal fissure separates the superior and inferior petrosal surfaces and exposes the posterolateral middle cerebellar peduncle (posterior and lateral to the root entry zone of CN5).1-4

ESSENTIALS STEPS OF THE PROCEDURE: Expanded retrosigmoid craniotomy is performed, including unroofing of the sigmoid sinus; petrosal fissure is split to expose the posterolateral middle cerebellar peduncle; entry point for resection of the cavernoma is identified; nims stimulator stimulator is used to confirm the absence of tracts and nuclei; myelotomy is performed; and cavernoma and its draining vein (but not the developmental venous anomaly) are removed using a combination of traction and countertraction against gliotic plane.

PITFALLS/AVOIDANCE OF COMPLICATIONS: Wide splitting of the horizontal cerebellar fissure minimizes retraction or resection of the cerebellum and offers the best angle of attack. Knowledge of brainstem anatomy and use of intraoperative navigation are critical to avoid complications.

VARIANTS AND INDICATIONS FOR THEIR USE: Far lateral through the middle cerebellar peduncle is a variant that can be used to resect pontine cavernomas if a caudocranial trajectory is preferred.

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Far lateral approach for dumbbell‑shaped C1 schwannomas

Acta Neurochirurgica (2024) 166:78

Dumbbell-shaped C1 schwannomas are rare lesions that involve both intra- and extradural compartments. Because of the intimate relationships these lesions develop with the third and fourth segments of the vertebral artery, surgical removal of these lesions remains a challenge.

Method We describe the key steps of the far lateral approach for dumbbell-shaped C1 schwannomas with a video illustration. The surgical anatomy is described along with the techniques for protecting the vertebral artery.

Conclusion Dumbbell-shaped C1 schwannomas can be safely removed by using the far lateral approach, surgical anatomy expertise, and intraoperative microvascular Doppler.

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A taxonomy for brainstem cavernous malformations: subtypes of medullary lesions

J Neurosurg 138:128–146, 2023

Medullary cavernous malformations are the least common of the brainstem cavernous malformations (BSCMs), accounting for only 14% of lesions in the authors’ surgical experience. In this article, a novel taxonomy for these lesions is proposed based on clinical presentation and anatomical location.

METHODS The taxonomy system was applied to a large 2-surgeon experience over a 30-year period (1990–2019). Of 601 patients who underwent microsurgical resection of BSCMs, 551 were identified who had the clinical and radiological information needed for inclusion. These 551 patients were classified by lesion location: midbrain (151 [27%]), pons (323 [59%]), and medulla (77 [14%]). Medullary lesions were subtyped on the basis of their predominant surface presentation. Neurological outcomes were assessed according to the modified Rankin Scale (mRS), with an mRS score ≤ 2 defined as favorable.

RESULTS Five distinct subtypes were defined for the 77 medullary BSCMs: pyramidal (3 [3.9%]), olivary (35 [46%]), cuneate (24 [31%]), gracile (5 [6.5%]), and trigonal (10 [13%]). Pyramidal lesions are located in the anterior medulla and were associated with hemiparesis and hypoglossal nerve palsy. Olivary lesions are found in the anterolateral medulla and were associated with ataxia. Cuneate lesions are located in the posterolateral medulla and were associated with ipsilateral upper-extremity sensory deficits. Gracile lesions are located outside the fourth ventricle in the posteroinferior medulla and were associated with ipsilateral lower-extremity sensory deficits. Trigonal lesions in the ventricular floor were associated with nausea, vomiting, and diplopia. A single surgical approach was preferred (> 90% of cases) for each medullary subtype: the far lateral approach for pyramidal and olivary lesions, the suboccipital-telovelar approach for cuneate lesions, the suboccipital-transcisterna magna approach for gracile lesions, and the suboccipital-transventricular approach for trigonal lesions. Of these 77 patients for whom follow-up data were available (n = 73), 63 (86%) had favorable outcomes and 67 (92%) had unchanged or improved functional status.

CONCLUSIONS This study confirms that the constellation of neurological signs and symptoms associated with a hemorrhagic medullary BSCM subtype is useful for defining the BSCM clinically according to a neurologically recognizable syndrome at the bedside. The proposed taxonomical classifications may be used to guide the selection of surgical approaches, which may enhance the consistency of clinical communications and help improve patient outcomes.

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The subatlantic triangle: gateway to early localization of the atlantoaxial vertebral artery

J Neurosurg Spine 29:18–27, 2018

Exposure of the vertebral artery (VA) between C-1 and C-2 vertebrae (atlantoaxial VA) may be necessary in a variety of pathologies of the craniovertebral junction. Current methods to expose this segment of the VA entail sharp dissection of muscles close to the internal jugular vein and the spinal accessory nerve. The present study assesses the technique of exposing the atlantoaxial VA through a newly defined muscular triangle at the craniovertebral junction.

METHODS Five cadaveric heads were prepared for surgical simulation in prone position, turned 30°–45° toward the side of exposure. The atlantoaxial VA was exposed through the subatlantic triangle after reflecting the sternocleidomastoid and splenius capitis muscles inferiorly. The subatlantic triangle was formed by 3 groups of muscles: 1) the levator scapulae and splenius cervicis muscles inferiorly and laterally, 2) the longissimus capitis muscle inferiorly and medially, and 3) the inferior oblique capitis superiorly. The lengths of the VA exposed through the triangle before and after unroofing the C-2 transverse foramen were measured.

RESULTS The subatlantic triangle consistently provided access to the whole length of atlantoaxial VA. The average length of the VA exposed via the subatlantic triangle was 19.5 mm. This average increased to 31.5 mm after the VA was released at the C-2 transverse foramen.

CONCLUSIONS The subatlantic triangle provides a simple and straightforward pathway to expose the atlantoaxial VA. The proposed method may be useful during posterior approaches to the craniovertebral junction should early exposure and control of the atlantoaxial VA become necessary.

 

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Surgical approach to posterior inferior cerebellar artery aneurysms

Acta Neurochir (2018) 160:295–299

The far-lateral is a standardised approach to clip aneurysms of the posterior inferior cerebellar artery (PICA). Different variants can be adopted to manage aneurysms that differ in morphology, topography, ruptured status, cerebellar swelling and surgeon preference.

Method We distinguished five paradigmatic approaches aimed to manage aneurysms that are: proximal unruptured; proximal ruptured requiring posterior fossa decompression (PFD); proximal ruptured not requiring PFD; distal unruptured; distal ruptured.

Conclusions Preoperative planning in the setting of PICA aneurysm surgery is of paramount importance to perform an effective and safe procedure, to ensure an adequate PFD and optimal proximal control before aneurysm manipulation.

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Foramen magnum meningiomas: surgical results and risks predicting poor outcomes based on a modified classification

J Neurosurg 126:661–676, 2017

This study aimed to evaluate neurological function and progression/recurrence (P/R) outcome of foramen magnum meningioma (FMM) based on a modified classification.

METHODS This study included 185 consecutive patients harboring FMMs (mean age 49.4 years; 124 females). The authors classified the FMMs into 4 types according to the previous classification of Bruneau and George as follows: Type A (n = 49, 26.5%), the dural attachment of the lesion grows below the vertebral artery (VA); Type B (n = 39, 21.1%), the dural attachment of the lesion grows above the VA; Type C1 (n = 84, 45.4%), the VA courses across the lesion with or without VA encasement or large lesions grow both above and below the bilateral VA; and Type C2 (n = 13, 7.0%), Type C1 plus partial/total encasement of the VA and extradural growth.

RESULTS The median preoperative Karnofsky Performance Scale (KPS) score was 80. Gross-total resection (GTR) was achieved in 154 patients (83.2%). Lower cranial nerve morbidity was lowest in Type A lesions (16.3%). Type C2 lesions were inherently larger (p = 0.001), had a greater percentage of ventrolateral location (p = 0.009) and VA encase-ment (p < 0.001), lower GTR rate (p < 0.001), longer surgical duration (p = 0.015), higher morbidity (38.5%), higher P/R rate (30.8%, p = 0.009), and poorer recent KPS score compared with other types. After a mean follow-up duration of 110.3 months, the most recent follow-up data were obtained in 163 patients (88.1%). P/R was observed in 13 patients (7.2%). The median follow-up KPS score was 90. Compared with preoperative status, recent neurological status was improved in 91 (49.2%), stabilized in 76 (41.1%), and worsened in 18 (9.7%) patients. The multivariate Cox proportional hazard regression model demonstrated Type C2 (HR 3.94, 95% CI 1.04–15.0, p = 0.044), nontotal resection (HR 6.30, 95% CI 1.91–20.8, p = 0.003), and pathological mitosis (HR 7.11, 95% CI 1.96–25.8, p = 0.003) as independent adverse predictors for tumor P/R. Multivariate logistic regression analysis identified nontotal resection (OR 4.06, 95% CI 1.16–14.2, p = 0.029) and pathological mitosis (OR 6.29, 95% CI 1.47–27.0, p = 0.013) as independent risks for poor outcome (KPS score < 80).

CONCLUSIONS The modified classification helped to predict surgical outcome and P/R in addition to the position of the lower cranial nerves. Preoperative imaging studies and neurological function should be reviewed carefully to establish an individualized management strategy to improve long-term outcome.

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A modified far-lateral approach for large or giant meningiomas of the posterior fossa

J Neurosurg 112:907–912, 2010. DOI: 10.3171/2009.6.JNS09120

Resecting large meningiomas along the posterior fossa convexity or cerebellopontine angle (CPA) through a suboccipital approach can be challenging. Limitations include a restricted angle of view, high venous pressures, and suboptimal brain relaxation. While a far-lateral craniotomy is a viable alternative, the risks associated with condylar resection are undesirable.

Methods. The authors retrospectively evaluated a modified far-lateral approach in a consecutive series of 12 patients with large or giant posterior fossa convexity and CPA meningiomas. This approach incorporates transversesigmoid sinus exposure and C-1 laminectomy, but there is no condylar resection.

Results. Between January 2006 and February 2008, 12 patients (mean age 52 years) presented with large or giant meningiomas of the posterior fossa convexity or CPA. The mean tumor volume was 72.6 cm3 (range 8–131 cm3). Signs and symptoms at presentation included headache (in 8 patients), cranial neuropathy (in 4), and progressive hemiparesis (in 4). There were no operative complications, and the majority of patients (9) had Simpson Grade I or II resections. There were no new permanent neurological deficits following resection, although 2 patients (17%) had transient deficits. The mean modified Rankin score decreased from 2.2 preoperatively to 0.6 postoperatively.

Conclusions. A modified far-lateral approach to the posterior fossa and CPA allows for safe, and often total, resection of large meningiomas with minimal morbidity. While avoiding the risks of condylar resection, this microsurgical strategy allows for greater field of view, minimal venous bleeding, and immediate access to the spinal subarachnoid space.

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