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Chapter Summary
• Context: Surgical approaches to the cervical spine must provide adequate exposure to the targeted pathology while safeguarding critical vascular, neural, and visceral structures densely packed within a compact anatomical corridor. The selection and execution of the approach depend heavily on the specific spinal level, differentiating between the craniocervical junction, upper cervical spine, and subaxial cervical spine. Surface landmarks, fascial planes, muscular layers, and the trajectory of the vertebral artery dictate the safe progress of dissection. This chapter describes anterior, anterolateral, transoral-transpharyngeal, and posterior approaches, detailing patient positioning, skin incision, deep dissection, and safe exposure boundaries. It contrasts the predominant risks associated with each route: dysphagia, dysphonia, recurrent laryngeal nerve injury, esophageal perforation, or Horner syndrome in anterior approaches; and severe hemorrhage, vertebral artery injury, spinal cord or nerve root injury, and cerebrospinal fluid leak in posterior approaches. Mastery of fascial planes, subperiosteal dissection, and meticulous terminal hemostasis are presented as cornerstones of surgical safety.
• Chapter Objective: To present the surgical anatomy necessary to understand and execute the primary approaches to the cervical spine. By the end, the reader should be able to identify key anatomical landmarks and fascial dissection planes; understand the specific technical steps of anterior, anterolateral, transoral-transpharyngeal, and posterior approaches; correlate each approach with its exposed spinal levels and neural structures; and recognize potential hazards, anatomical boundaries, and strategies to minimize complications.
• Anatomical Landmarks and Patient PositioningThe cervical spine consists of seven vertebrae, with marked anatomical differences between C1–C2 (upper cervical) and C3–C7 (subaxial spine). Anterior surface landmarks correlate predictably with vertebral levels: hard palate to the anterior arch of C1; inferior border of the mandible to C2–C3; hyoid bone to C3; thyroid cartilage to C4–C5; cricoid cartilage and Chassaignac tubercle (carotid tubercle on C6 transverse process) to C6. The vertebral artery ascends through the transverse foramina lateral to the uncinate process, positioned anterior to the exiting spinal nerve root. For anterior approaches, the patient is placed supine with slight cervical extension, head stabilized on a donut headrest, and gentle caudal shoulder taping to improve fluoroscopic visualization. For posterior approaches, the prone position is used with the head rigidly secured in a Mayfield clamp or skull tongs in a neutral or slightly flexed position with the head elevated above the heart.
• Anterior and Anterolateral ApproachesThe classic Smith-Robinson anterior approach utilizes a transverse skin crease incision and exploits the natural plane medial to the carotid sheath. The sternocleidomastoid muscle and carotid sheath (containing common carotid artery, internal jugular vein, and vagus nerve) are mobilized laterally, while the visceral axis (trachea, esophagus, and thyroid gland) is retracted medially. Deep dissection divides the prevertebral fascia, exposing the longus colli muscles, which are elevated subperiosteally to expose the anterior longitudinal ligament and vertebral bodies. The anterolateral approach uses a longitudinal incision along the anterior border of the sternocleidomastoid, providing extensive exposure of the lateral vertebral body, uncovertebral joints, and vertebral artery. Primary complications include dysphagia (most common immediate postoperative complaint), dysphonia (recurrent or superior laryngeal nerve injury), esophageal perforation, Horner syndrome (sympathetic trunk injury over longus colli), and hematoma causing airway obstruction.
• Transoral-Transpharyngeal ApproachIndicated for extradural lesions located on the ventral aspect of the craniocervical junction, this approach exposes the lower clivus, anterior rim of the foramen magnum, anterior arch of C1, odontoid process, and C2 vertebral body (extensible to C3). It requires adequate interincisal mouth opening to accommodate specialized self-retaining retractor systems. The posterior pharyngeal wall is incised in the midline, elevating a full-thickness myomucosal flap followed by subperiosteal dissection. Lateral exposure must strictly be restricted to 15 mm from the midline to avoid injuring the hypoglossal nerve, Eustachian tube orifice, and vertebral arteries. Prophylactic broad-spectrum antibiotics, vigorous wound irrigation, and airtight two-layer pharyngeal closure are mandatory. Primary risks include deep wound infection, pharyngeal dehiscence, respiratory compromise, CSF fistula with meningitis, and craniocervical instability requiring posterior fixation.
• Posterior Cervical ApproachesAt the craniocervical junction, a midline incision through the avascular nuchal ligament exposes the suboccipital bone and posterior elements of C1–C2. Dissection must strictly preserve greater occipital nerves, facet capsules, and the suboccipital venous plexus while respecting the vertebral artery traversing the groove on the superior aspect of the C1 posterior arch. Lateral dissection on the C1 arch must not exceed 1.5 cm from the midline in adults (1.0 cm in children) and should stay within 8 mm of the superior border. From C3 to C7, a midline subperiosteal exposure performed in a caudocranial direction exposes spinous processes, lamina, lateral masses, ligamentum flavum, and facet joints. Complications include vertebral artery injury during lateral mass or pedicle screw placement, nerve root injury, dural tear, spinal cord contusion, and significant intraoperative bleeding.
• Clinical Application: Approach selection must be dictated by disease pathology, vertebral level, and anatomical orientation. Ventral lesions between C3 and C7 are ideally approached via the anterior Smith-Robinson or anterolateral corridor; ventral craniocervical pathologies require transoral or endoscopic endonasal/transoral approaches; and dorsal pathologies (multilevel stenosis, posterior instability, lateral tumors) are addressed via posterior laminectomy, laminoplasty, or instrumentation. Preoperative CT angiography or MRI should always evaluate vertebral artery course and anomalies (such as high-riding vertebral artery or persistent proatlantal arteries). Intraoperatively, strict subperiosteal dissection protects the cervical sympathetic trunk located over the lateral longus colli, the recurrent laryngeal nerve within the tracheoesophageal groove, and the vertebral artery laterally. In posterior high cervical exposure, staying within defined safe margins on the C1 arch prevents catastrophic vertebral artery laceration. At closure, thorough hemostasis and careful drain placement prior to extubation are vital to prevent neck hematoma and acute life-threatening airway compromise.
