Anterolateral Cervical Approach (Vertebral Artery Exposure)

What it exposes The anterolateral approach to the cervical spine (Verbiest) is the direct surgical corridor to the intervertebral foramen, the vertebral artery and the cervical nerve roots. It is developed medial to sternocleidomastoid and lateral to the carotid sheath, then deepened onto longus colli and the transverse processes to expose the V2 segment of the vertebral artery as it ascends through the foramina transversaria. It is the only anterior route that gives controlled access to the vertebral artery and the lateral vertebral body, and it is usually shared with neurosurgery or vascular surgery.

• Vertebral artery decompression for external compression causing vertebrobasilar insufficiency (osteophytes, fibrous bands, anomalous bony impingement at the uncovertebral joint)
• Surgical exposure of the vertebral artery for repair (dissection, aneurysm, arteriovenous fistula), typically in partnership with vascular surgery
• Lateral cervical tumours with vertebral artery involvement (nerve sheath tumours such as schwannoma or neurofibroma, meningioma, and selected bony or soft-tissue sarcomas)
• Foraminal and nerve root pathology requiring anterior decompression where the artery must be controlled and protected
• Biopsy and resection of lateral mass or transverse process lesions Why this approach is chosen: the vertebral artery and the lateral gutter are invisible and unreachable from the standard anterior (Smith-Robinson) approach, which is built for the vertebral bodies and discs medial to the longus colli. The anterolateral approach deliberately opens the interval lateral to the carotid sheath to bring the surgeon onto the anterior tubercles of the transverse processes and the foramina transversaria that house V2. Contraindications:
• Unmapped vertebral artery anatomy — operating without pre-operative vascular imaging is unsafe
• Active infection of the overlying skin
• Inability to tolerate the position or prolonged anaesthesia
• Medial/anterior pathology adequately reached by the standard anterior approach (the anterolateral route adds risk without benefit)
• A lesion better managed endovascularly (many VA aneurysms, dissections and fistulas are now treated by interventional neuroradiology) Alternative and complementary approaches:
• Standard anterior approach (Smith-Robinson): vertebral bodies, discs and medial longus colli; medial to the carotid sheath — does NOT give lateral or VA access
• Posterior approach: lateral mass and pedicle screws, laminectomy/foraminotomy from behind; the VA is approached from its posterior aspect at C1-C2
• Far-lateral / transcondylar (skull base): for V3 and V4 lesions at the craniocervical junction
• Endovascular therapy: first-line for many VA aneurysms, dissections and fistulas ### Position and landmarks Position. Supine with a small bolster between the scapulae for gentle neck extension; the head rests on a gel ring or Mayfield support turned roughly 30 degrees to the contralateral side to flatten sternocleidomastoid and open the angle between it and the carotid sheath. The neck is in slight extension for the mid-cervical segment (slight flexion for a higher retro-styloid exposure). Arms are tucked; bony prominences padded; an image intensifier is available for intra-operative level confirmation. Key bony landmarks:
• Carotid tubercle (Chassaignac's tubercle) — the large, palpable anterior tubercle of the C6 transverse process; the single most important landmark for level identification
• Cricoid cartilage — lies opposite C6
• Hyoid bone — opposite C3
• Thyroid cartilage — opposite C4 to C5
• Mastoid process and the transverse process of C1 — landmarks for the high (V3) extension Key soft-tissue landmarks: the medial (anterior) border of sternocleidomastoid (the incision line); the carotid pulse (confirms the sheath swept medially); the external jugular vein (crosses SCM superficially, usually ligated); the greater auricular nerve (emerges at Erb's point and crosses SCM superficially). Incision planning. A longitudinal incision along the anterior border of SCM, centred on the target level (typically 8 to 12 cm depending on the number of segments). For the V3 / C1-C2 extension the incision curves upward and backward toward the mastoid in a hockey-stick (inverted-L) shape; for the distal (V1, low cervical) extension it is carried down toward the supraclavicular fossa. ### Pre-operative assessment and imaging History and examination. Look for symptoms of vertebrobasilar insufficiency — vertigo, diplopia, dysarthria, drop attacks, bilateral visual disturbance, ataxia — classically provoked by head rotation (Bow Hunter's syndrome suggests dynamic VA compression). Examine the cranial nerves and cerebellar signs, the cervical and upper-limb motor and sensory examination, and document vocal cord function (often assessed pre-operatively in revision or right-sided cases). Vascular imaging is mandatory in every case.

Structural imaging. Plain radiographs including flexion-extension views if instability or dynamic compression is suspected; MRI for cord signal, tumour extent, and disc/osteophyte relationship to the artery and nerve root; CT for bony detail of the transverse process, foramen and tumour matrix. Decision-making. Operative management is the default when there is documented, symptomatic, surgically correctable VA compression not amenable to endovascular treatment, a lateral tumour requiring resection with VA control, or nerve root decompression that cannot be achieved safely from another route. Endovascular therapy is first-line for most VA aneurysms, dissections and fistulas. Proximal and distal control of the artery is planned before the lesion is entered, and a vessel loop is placed around the artery proximal and distal to the working segment.

Work down through the layers along the anterior border of sternocleidomastoid, pass lateral to the carotid sheath, and deepen onto the prevertebral muscles and the transverse processes, where the transverse foramen is unroofed to expose and mobilize the V2 segment. ### Vertebral artery segments — the anatomy that drives the exposure The vertebral artery is conventionally divided into four segments. Knowing them is mandatory before describing this approach.

Bony anatomy. Each cervical vertebra bears a transverse process formed by an anterior tubercle (the homologue of a rib) and a posterior tubercle, joined by a costo-transverse bar that encloses the transverse foramen. The vertebral artery, its accompanying veins and a sympathetic plexus pass through each foramen. The anterior tubercles — particularly the carotid tubercle at C6 — are the deep bony targets of the approach. The uncovertebral joints (joints of Luschka) lie just medial to the artery and are the usual source of the osteophytes that compress it. Within the foramen the artery occupies the postero-medial part at most levels, so the bone to remove is the antero-lateral wall. ### Exposure sequence

Structures at risk

Vertebral artery injury management. If recognized intra-operatively, achieve immediate proximal and distal control, compress with a tamponade, and call vascular assistance. Avoid blind clipping — the artery can often be repaired primarily or with a patch. If sacrifice is unavoidable and the artery is non-dominant (confirmed on pre-op imaging and occlusion testing), ligation may be tolerated. Plan post-operative antiplatelet therapy and imaging as guided by the vascular team. ### Extensile options Proximal (cephalad) extension toward the mastoid — V3 / C1-C2: carry the incision up and back toward the mastoid in a hockey-stick shape; SCM may be mobilized or detached from the mastoid to gain the retro-styloid corridor. Gives access to the V3 loop around C1, the C1-C2 joint and the suboccipital region. Additional dangers: the C1 and C2 nerve roots, the suboccipital (C1) nerve, the spinal accessory nerve, and the variable course of V3 behind the C1 arch. Distal (caudal) extension toward the supraclavicular fossa — V1 / lower cervical: carry the incision down toward the clavicle and the sternoclavicular joint. Gives access to the V1 segment, the vertebral artery origin from the subclavian, and the lower cervical levels. Additional dangers: the phrenic nerve on anterior scalene (diaphragm paralysis), the thoracic duct on the left (chylothorax if injured), the subclavian artery and vein, and the lower trunk of the brachial plexus. Combined approaches: with the standard anterior approach when both the vertebral body/disc and the lateral gutter/VA need access; with a posterior approach for occipito-cervical fixation after lateral resection; with a far-lateral transcondylar approach for craniocervical junction lesions. ### Complications

Closure and aftercare Closure in layers. Reapproximate the prevertebral fascia and reattach longus capitis/SCM over the foramen to cover the artery; place a suction drain in the dead space exiting away from the great vessels; close the platysma with absorbable suture and the skin with a subcuticular absorbable suture. Document a full post-operative neurological examination including Horner's signs and vocal cord function, and image the artery if it was repaired or sacrificed. Aftercare. Neurovascular observation including Horner's signs, voice (recurrent laryngeal) and limb neurology; watch for an expanding haematoma (an airway emergency). Mobilize as the wound allows, with a soft collar for comfort if the approach was extensive. Antiplatelet therapy if the artery was repaired or manipulated, per vascular guidance. Follow up with vascular imaging (CTA/MRA) to confirm patency and decompression, and oncology surveillance imaging for tumour cases.

• Vertebral artery decompression — removal of the compressing osteophyte from the uncovertebral joint, or division of a fibrous band, after unroofing the foramen and mobilizing the artery, to relieve external mechanical compression causing vertebrobasilar insufficiency.
• Lateral tumour resection — nerve sheath tumours (schwannoma, neurofibroma), meningioma or selected bony tumours involving the lateral mass and transverse process, resected with the artery controlled and mobilized off the tumour capsule where necessary.
• Anterior foraminotomy / nerve root decompression — removal of the anterior portion of the facet and the uncinate process to decompress the exiting nerve root, with the VA protected laterally.
• Vertebral artery repair / reconstruction — in partnership with vascular surgery: arteriotomy for embolectomy, primary repair, patch angioplasty or re-anastomosis, having obtained proximal and distal control.
• Biopsy — targeted biopsy of a lateral mass or transverse process lesion under direct vision, avoiding the artery.

Guidelines, registries & global practice The anterolateral approach to the cervical spine for vertebral artery exposure is a specialist technique used in major spine, neurosurgical and vascular centres worldwide. It is relevant across examination systems, most often at the operative surgery and applied basic science level. The principles converge globally: pre-operative vascular imaging is mandatory, the approach uses the interval lateral to the carotid sheath, and the sympathetic chain and recurrent laryngeal nerve are the named structures to preserve.

Global practice variation: in well-resourced centres the approach is supported by CTA/MRA, intra-operative imaging, neurophysiological monitoring and a scrubbed vascular partner. In resource-limited settings the same anatomical principles apply, but the approach is reserved for cases where simpler alternatives have been exhausted, and pre-operative vascular mapping may rely on Doppler or transfer to a referral centre. Indications skew toward tumour and trauma where decompression cannot wait, while elective VA repair is increasingly concentrated in specialized units. Consent (globally applicable): discuss vertebral artery injury with the possibility of posterior-circulation stroke, Horner's syndrome from sympathetic chain injury, recurrent laryngeal nerve palsy causing hoarseness (higher on the right), nerve root injury, and the small possibility of requiring arterial sacrifice or reconstruction. Patients should understand that many vertebral artery aneurysms, dissections and fistulas are now treated endovascularly, and open surgery is reserved for specific indications.