Anterior Retropharyngeal Approach to the Upper Cervical Spine (C1–C3)

What it exposes. The anterior retropharyngeal approach (Robinson–Southwick, with the McAfee modification) gives extraoral access to the craniovertebral junction — the anterior arch of C1, the odontoid process, and the bodies of C2 and C3. It reaches the same anterior column as a transoral route but through a sterile, clean field. Why extraoral. By staying clear of the oral cavity it avoids salivary bacterial contamination — infection after retropharyngeal surgery runs 1–4 percent versus 10–20 percent after a transoral route — which matters most for implant work such as odontoid screws, anterior C1–C2 plating and strut grafting. When pathology drops below C3, the same plane continues seamlessly into a standard Smith–Robinson anterior cervical exposure. Indications - Odontoid fracture nonunion or malunion needing direct anterior access

• Basilar invagination or cranial settling with anterior compression
• Upper cervical (C1–C3) tumours — chordoma, metastasis, plasmacytoma
• Pyogenic or tuberculous osteomyelitis or discitis of C1–C3 needing debridement and grafting
• Anterior C1–C2 or C2–C3 corpectomy and reconstruction when the transoral route is contraindicated
• Revision anterior surgery after failed transoral or posterior procedures Contraindications - Active infection of the submandibular or anterior neck skin
• Severe trismus or limited mouth opening (relative — may still be feasible)
• An unstable cervical spine without prior posterior stabilisation (relative)
• Previous radical neck dissection on the ipsilateral side (altered vascular anatomy)
• Patient factors precluding supine positioning with head extension Alternative approaches

Position & landmarks. Supine on a radiolucent table, with a shoulder roll and the head extended 10–15 degrees and rotated 30–40 degrees away from the operative side. Gardner–Wells tongs or a Mayfield head holder give controlled positioning for odontoid screw trajectory; arms are tucked with slight traction for fluoroscopic access. The C-arm is set for true lateral and open-mouth AP views of C1–C2, the endotracheal tube is secured on the contralateral side, and MEP/SSEP neuromonitoring is recommended. Palpable landmarks: the inferior border of the mandible (incision placed 2–3 cm below it), the hyoid at C3 (marks the hypoglossal nerve), the thyroid cartilage (C4–C5), the cricoid (C6), the submandibular gland and the carotid pulse. Incision choice

The exposure is built in layers from the skin to the prevertebral fascia: protect the marginal mandibular nerve superficially, open the plane between the carotid sheath and the visceral column, then detach the longus colli to reach the anterior column of C1–C3.

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Structures at risk, by layer

Nerve-injury management. Marginal mandibular or hypoglossal neuropraxia is observed — most recover within 3–6 months. Superior laryngeal nerve injury is managed with voice therapy and aspiration precautions. A permanent deficit after 12 months may need medialisation thyroplasty or tongue-suspension procedures. Complications

Extensile options - Caudal (Smith–Robinson): lengthen the incision along the anterior border of the sternocleidomastoid and continue in the same plane to C7 — the commonest extension, allowing ACDF, corpectomy or disc arthroplasty without repositioning.

• Proximal: limited extension toward the mastoid tip by mobilising the facial nerve further cephalad and dividing the posterior belly of digastric; true clival access needs a separate transoral or endoscopic endonasal route.
• Bilateral: two simultaneous retropharyngeal approaches for midline tumours or extensive infection — wider lateral exposure but higher bilateral nerve risk.
• Combined anterior–posterior (360-degree): anterior decompression first, then posterior occiput–C2 or C1–C3 instrumentation in the same or a staged procedure. Closure. Copious antibiotic-saline irrigation and meticulous haemostasis of the retropharyngeal space and carotid sheath. Place a drain in the retropharyngeal space through a separate stab. Approximate the longus colli and prevertebral fascia where possible, close the investing fascia over the carotid sheath, then platysma with absorbable suture and skin with a subcuticular suture. Assess for airway oedema before extubation — keep the patient intubated overnight or perform a tracheostomy if retraction was extensive.

• Odontoid screw fixation — anterior single or double screw for a type II odontoid nonunion, preserving C1–C2 rotation.
• Anterior cervical corpectomy — C2 or C3 corpectomy with strut-graft or cage reconstruction.
• Smith–Robinson anterior cervical approach — the caudal extension for C3–C7 work.
• Anterior C1–C2 transarticular screw placement and anterior C1–C2 plating and fusion.
• Anterior debridement and grafting for upper cervical pyogenic or tuberculous osteomyelitis.
• Resection of anterior craniovertebral junction tumours (chordoma, metastasis).
• Basilar invagination decompression (odontoidectomy) and revision anterior surgery after failed transoral or posterior procedures.

Global practice. Upper cervical pathology is managed at tertiary spine centres worldwide, and the anterior retropharyngeal approach is recognised across contemporary practice as the standard extraoral route to the craniovertebral junction when a clean field is required. Where guidance converges

Population evidence - Odontoid fractures are about 15 percent of all cervical spine fractures; nonunion after non-operative treatment ranges from 10 to 50 percent depending on fracture type and patient factors.

• Anterior odontoid screw fixation fuses in 85 to 95 percent of appropriately selected cases through this exposure.
• Infection after retropharyngeal surgery is consistently lower (1–4 percent) than after transoral surgery (10–20 percent). Consent (globally applicable). Discuss marginal mandibular nerve injury (transient 10–15 percent, permanent less than 3 percent), hypoglossal nerve injury (transient 5–10 percent), superior laryngeal nerve injury with voice change and aspiration (5–15 percent), dysphagia (20–40 percent transient), airway compromise needing re-intubation or tracheostomy (5–15 percent), infection (2–5 percent), nonunion (5–15 percent), and possible future revision or combined posterior stabilisation.