Anterior Cervical Diskectomy and Fusion: Technique, Complications, and Rehabilitation

Sreeharsha V. Nandyala, BA

Alejandro Marquez-Lara, MD

David S. Cheng, MD

Kern Singh, MD

Dr. Singh or an immediate family member has received royalties from Pioneer, Stryker, and Zimmer; serves as a paid consultant to DePuy, A Johnson & Johnson Company, Stryker, and Zimmer; has stock or stock options held in Avaz Surgical and Vital 5; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research–related funding (such as paid travel) from SLACK Incorporated, Thieme, and Wolters Kluwer Health–Lippincott Williams & Wilkins; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons, the Cervical Spine Research Society, ISASS—the International Society for the Advancement of Spine Surgery, the Scoliosis Research Society, SMISS—the Society for Minimally Invasive Spine Surgery, Spine Surgery Today, the Vertebral Columns–ISASS, and Wolters Kluwer Health–Lippincott Williams & Wilkins. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Cheng, Dr. Marquez-Lara, and Dr. Nandyala.

Introduction

Degenerative disease of the cervical spine is a frequent finding that may result in symptomatic cervical radiculopathy. Radiographic evidence demonstrates at least one degenerative finding in the cervical spine on radiographs by age 65 years in nearly 95% of men and 70% of women. Cervical total disc replacement (TDR) and anterior cervical discectomy and fusion (ACDF) are both indicated surgical interventions for this condition.

ACDF was first described in the 1930s. Significant ensuing modifications have improved patient safety and clinical outcomes. This procedure involves the decompression of neural elements from a herniated disc or degenerative disc disease causing spinal stenosis along with concurrent bony fusion of the affected spinal levels.

Prospective randomized studies demonstrate that a structured regimen of postoperative physical therapy is associated with improved functional outcomes, less opioid utilization, and faster recovery. The goal of postoperative rehabilitation is to improve neck range of motion (ROM); improve muscle endurance; and address procedural complications, including dysphagia and dysphonia. This chapter provides a discussion of ACDF and highlights the postoperative complications, restrictions, recovery, and rehabilitation goals.

Surgical Procedure: Anterior Cervical Diskectomy and Fusion

Indications

Persistent neck pain and/or arm pain, numbness, or tingling despite 6 weeks of conservative management with rest, physical therapy, and nonsteroidal anti-inflammatory drugs (NSAIDs)
Diagnostic studies (MRI, CT ± myelogram) that demonstrate degenerative disc disease or herniated disc disease with corresponding symptoms
Myelopathy (balance disturbances, slow-wide based gait)
Tumor/trauma

Contraindications

Superficial infection
Tracheostomy
History of anterior neck radiation

Surgical Technique

Superficial anatomic landmarks include
- Hyoid at C3
- Thyroid cartilage at C4–C5
- Cricoid cartilage at C6
Step 1
- A horizontal incision is made medial to the sternocleidomastoid (SCM) muscle.
- The side of approach should be determined based on the surgeon’s comfort and experience.
Step 2
- The platysma is divided in line with the skin incision.
- The external jugular vein helps to identify the tracheosophageal groove.
Step 3
- The SCM and carotid sheath are retracted laterally while the tracheoesophageal complex is retracted medially.
- The recurrent laryngeal nerve lies in the tracheoesophageal groove and is susceptible to injury.
Step 4
- The longus coli are swept laterally to expose the superficial disc space.
- The sympathetic chain lies superficial to the longus coli; thus, care must be taken to position the retractors deep to this muscle.
Step 5
- A knife or electrocautery is utilized to perform the annulotomy.
- Straight and curved curettes are utilized to remove the disc material.
Step 6
- A microcurette or nerve hook with a 1-mm Kerrison rongeur is utilized to remove the posterior longitudinal ligament.
Step 7
- A high-speed burr is utilized to decorticate the endplates to improve bone graft contact.
Step 8
- A trial sizer is placed to approximate the intervertebral space and an appropriately sized bone graft is gently impacted into place.
Step 9
- An anterior cervical plate is applied and cervical screws are placed through the plate typically measuring 12 mm to 16 mm.
- The choice between fixed versus variable screws depends on the surgeon’s preference.
Step 10
- The retractors are removed, and the muscle and skin incisions are closed primarily.
- The utilization of a drain (e.g., Penrose) depends on the surgeon’s preference.

Complications

Pseudarthrosis

Patients may present with recurrent pain that gradually worsens over a period of months. Proper patient selection is paramount in reducing the risk of pseudarthrosis. Risk factors include smoking, osteoporosis, chronic steroid use, obesity, and malnutrition. Pseudarthrosis can also be associated with implant failure and fracture, thus requiring reinstrumentation. Patients with worsening pain in the postoperative period must be evaluated clinically and radiographically for evidence of pseudarthrosis.

Adjacent Segment Degeneration

Although an ACDF is widely accepted and considered the classic interventional management for cervical degenerative pathology, the reduction in adjacent level kinematics, progression of adjacent level degeneration, and an increased intradiscal pressure and facet forces eventually cause wear and tear of the adjacent spinal levels and produces pain. As such, postoperative physical therapy and home exercise should focus on maintaining adequate neck ROM to strengthen the neck musculature as well as endurance in an effort to reduce pain and improve postoperative kinematics.

Dysphagia

Postoperative dysphagia is a well-published complication of ACDF, with a rate of 1.7% to 50.3%. The pathophysiology of postoperative dysphagia is not fully understood and is subject to further study. Video-fluoroscopic swallow studies in patients who underwent anterior cervical spine surgery reported a range of etiologies that spanned all stages of swallowing. Notably, prevertebral soft-tissue swelling, posterior pharyngeal wall residue, and impaired upper esophageal sphincter opening are possible etiologies. Hypoglossal, glossopharyngeal, and recurrent laryngeal nerve injuries are also proposed explanations for postoperative dysphagia. Postoperative dysphagia has been reported to improve with time, with a mean incidence of 19.8% at 6 months, 16.8% at 12 months, and 12.9% at 24 months after ACDF. Some radiographic studies have reported an incidence of 50% in the early postoperative period in cervical surgery with anterior instrumentation.

Dysphonia

Postoperative hoarseness and dysphonia are also well-known complications of anterior cervical spine surgery. The published rates range from 0.1% to 21%. A wide range of etiologies have been suggested; the most common is believed to be pharyngeal and laryngeal edema by virtue of retraction devices and the natural postoperative healing process. Other causes include injury to the recurrent laryngeal nerve (RLN) from stretching, direct lesion, or retraction. In addition, laryngeal injury from endotracheal intubation is also a suspected cause of postoperative hoarseness and dysphonia. Some authors have implemented protocols to monitor the intraoperative endotracheal cuff pressure to limit the extent of laryngeal injury. Postoperative hoarseness and dysphonia can be long-standing, with up to 12% of patients having persistent symptoms for more than 6 months.

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