POSTERIOR CERVICAL FUSION
Posterior cervical fusion is a type of spinal surgery that aims to relieve pain and instability in the cervical spine (the neck region). This procedure is typically considered when other treatments, such as physical therapy or medications, have failed to provide relief. The main reasons for undergoing this surgery include conditions like spinal stenosis, cervical degenerative disc disease, fractures, tumors, or instability caused by rheumatoid arthritis.
Here's an overview of the procedure and its implications:
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Objective: The primary goal is to stabilize the cervical spine by fusing two or more vertebrae together. This is done to eliminate the motion between these vertebrae, which can reduce pain and stabilize the spine.
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Procedure:
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Approach: As the name suggests, the surgery is performed from the back (posterior) of the neck.
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Bone Grafts: The surgeon places bone graft material between the vertebrae. This material can be sourced from the patient’s own body (autograft), a donor (allograft), or synthetic materials.
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Hardware: Metal plates, screws, and rods may be used to hold the vertebrae together while the bone graft heals and fuses the vertebrae.
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Anesthetic Implications for Posterior Cervical Fusion
Anesthesia type: General anesthesia with ETT. Partial or total intravenous anesthesia (TIVA) to optimize neuromonitoring
Airway: ETT
Preoperative:
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Baseline neurologic assessment of sensory and motor function
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Assess cervical range of motion
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Patients may be difficult to intubate due to the inability to place in the sniffing position
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Intubate with the head in the neutral position
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Log rolling patient: Maintain cervical neutrality while moving patient to prone position
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Consider having a video laryngoscope or fiberoptic bronchoscopy
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Bed may be turned 180 degrees
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Spinal cord trauma may be associated with loss of sympathetic tone, which can cause peripheral vasodilation and bradycardia
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Fractures above C5 may result in quadriplegia and loss of phrenic nerve function
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Manipulation of the head and neck could produce permanent injury
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Patients are often on chronic pain medications
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Find out if the surgeon wants the patient relaxed by neuromuscular blockers
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Shared airway with surgeon
Intraoperative:
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Neurologic monitoring may be used during the cervical fusion
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Somatosensory evoked potentials (SSEPs) monitoring may be used. SSEPs assess the integrity of the posterior spinal cord
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Volatile anesthetics over 0.5 MAC decrease amplitude and increase the latency of SSEP waveforms (false positive)
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Motor evoked potentials (MEPs) monitoring may be used. MEPs assess the integrity of the anterior spinal artery
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MEPs are affected by neuromuscular blocking agents
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The bispectral index (BIS) monitor can be used
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Tongue lacerations from MEPs can occur. Apply tongue protection
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Duration: 1-4 hours
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Position: Prone, arms tucked
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EBL 50-500 ml
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Fluoroscopy or portable X-ray is used
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Controlled hypotension may be requested to reduce bleeding
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The overall aim is to keep patients euvolemic, while avoiding excessive fluid administration
Postoperative:
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Extubation/emergence: Avoid coughing and bucking
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Perform neurologic exam
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Cervical collar may be utilized to allow bone graft healing
Complications:
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Acute spinal cord injury
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Infection
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Bleeding
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Quadriplegia
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Myelopathy
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Nerve injury
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Airway edema
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Chronic pain
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Thrombophlebitis
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Nonunion of the cervical vertebrae
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Venous air embolism
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Dural tear
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Bone graft migration
Sources:
Elisha, S. (2010). Case Studies in Nurse Anesthesia.
Khanna P, Sarkar S, Garg B. Anesthetic considerations in spine surgery: What orthopaedic surgeon should know! J Clin Orthop Trauma. 2020 Sep-Oct;11(5):742-748. doi: 10.1016/j.jcot.2020.05.005. Epub 2020 May 11. PMID: 32879562; PMCID: PMC7452283.
Macksey, L. F. (2011). Surgical procedures and anesthetic implications: A handbook for nurse anesthesia practice.
Jaffe, R. A. (2020). Anesthesiologist's Manual of Surgical Procedures (6th ed.).
Singh-Radcliff, N. (2013). 5-Minute Anesthesia Consult.