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Adjacent segment disease after anterior cervical decompression and fusion


Introduction

Anterior cervical decompressions and fusions (ACDFs) are one of the most common spine surgeries worldwide and the gold standard treatment for symptomatic cervical spondylosis. Adjacent segment disease is a very common sequela and occurs in about 26% of all patients within 10 years from surgery requiring reoperation. The best treatment modality is a matter of debate and should be tailored to the patient. In this chapter, we present a case of adjacent segment disease following ACDF.

Example case

Chief complaint: neck pain and hoarseness

History of present illness: The patient is a 62-year-old female with a history of three prior anterior cervical decompressions and fusions (ACDFs) spanning from C3 to C6. She was referred for worsening neck pain over the past 3 months. Her pain was mechanical in nature and there was no accompanying radiculopathy. She denied weakness or difficulty ambulating. She underwent imaging concerning for cervical kyphotic deformity with C5–6 pseudoarthrosis and adjacent segment degeneration at C2–3 and C6-T1, causing spinal cord compression and neuroforaminal stenosis ( Fig. 4.1 ).

Fig. 4.1, Preoperative imaging. (A and C), Sagittal and axial computed tomography (CT) bone windows demonstrating sagittal malalignment secondary to cervical kyphotic deformity and two separate ACDF plates spanning C3–6 with appropriate fusion from C3 to 5 and incomplete fusion and pseudoarthrosis at C5–6. Note the superior plate overlying the C2–3 disc space resulting in adjacent segment ossification and osteophyte formation. (B) Sagittal T2 magnetic resonance image demonstrating adjacent segment degeneration at C2–3 and C6-T1, causing spinal cord compression and neuroforaminal stenosis.

Medications: none

Allergies: no known drug allergies

Past medical history: none

Past surgical history: previous three ACDFs (the most recent was 1 year ago)

Family history: noncontributory

Social history: none

Physical exam: awake, alert, and oriented to person, place, and time; cranial nerves II-XII intact, bilateral deltoids, biceps, triceps, grip, and hand intrinsic muscles 5/5; iliopsoas, knee flexion, knee extension, dorsiflexion, plantar flexion 5/5. Reflexes: 2+ in bilateral biceps, triceps, brachioradialis with negative Hoffman; 2+ in bilateral patella and ankle and no clonus or Babinski; sensation is intact to light touch.

  • Alvaro Camparo, MD

  • Ramiro Barrera, MD

  • Neurosurgery

  • Hospital Padilla–Tucuman

  • Universidad Nacional de Tucuman

  • Tucuman, Argentina

  • Scott Daffner, MD

  • Orthopedic Surgery

  • West Virginia University

  • Morgantown, West Virginia, United States

  • Daniel C. Lu, MD, PhD

  • Neurosurgery

  • University of California at Los Angeles

  • Los Angeles, California, United States

  • Luiz Robert Vialle, MD

  • Orthopedic Surgery

  • Pontifical Catholic University of Parana

  • Curitiba, Brazil

Preoperative
Additional tests requested

  • C-spine dynamic x-ray

  • C-spine dynamic MRI

  • C-spine upright/AP/lateral/flexion/extension x-ray

  • DEXA

  • Laboratories (CBC/ESR/CRP/vitamin D/calcium)

  • C-spine flexion-extension x-rays

  • DEXA

  • Endocrinology evaluation

  • Anesthesia evaluation

  • C-spine MRI axial

  • Dynamic x-rays

  • Vocal cord evaluation

Surgical approach selected Anterior C2–3 decompression and fusion Posterior C4-T2 fusion Posterior C2-T2 fusion with possible C2-C3 laminectomy/decompression If conservative management fails, anterior C2–3, C5–6, and C6–7 decompression and fusion
Goal of surgery Decompression, fusion Treatment of pseudoarthrosis, fusion Treatment of pseudoarthrosis for pain and spinal cord protection Decompression, cervical lordosis reconstruction
Perioperative
Positioning Supine Prone, with Mayfield pins Prone, with Mayfield pins Supine
Surgical equipment

  • Fluoroscopy

  • Surgical microscope

  • PEEK implant

  • IOM (MEP/SSEP)

  • Fluoroscopy

  • IOM (MEP/SSEP)

  • Fluoroscopy

  • Surgical navigation

  • Wired endotracheal tube

  • Nasopharyngeal tube

Medications NSAIDs Maintain MAP >80 None None
Anatomical considerations Carotid sheath, trachea, esophagus Vertebral artery, nerve roots Vertebral artery, midline avascular plane Carotid artery, esophagus, vertebral artery, laryngeal nerve
Complications feared with approach chosen Dysphagia, recurrent laryngeal nerve palsy, hematoma, esophageal perforation Wound infection, hematoma, adjacent segment disease Pseudoarthrosis Esophageal fistula, dysphonia
Intraoperative
Anesthesia General General General General
Exposure C2–3 C4-T2 C2-T2 C2-C7
Levels decompressed C2–3 None None C2–3, C5–6, C6–7
Levels fused C2–3 C4-T2 C2-T2 C2-C7
Surgical narrative Position supine, right transverse cervical neck incision, vertical incision in platysma, blunt dissection between sternocleidomastoid and carotid sheath, retract carotid sheath laterally and trachea/esophagus medially, confirmation of space with needle and fluoroscopy, separation of longus colli muscles, discectomy with microscope, percutaneous bone graft extraction with needle biopsy of iliac crest, placement of PEEK with screws in the space, closure with a drain Baseline IOM, position prone, confirm alignment with x-ray, midline posterior incision, subperiosteal dissection to expose C4–7 lateral masses and proximal transverse processes of T1 and T2, place lateral mass screws from C4–6 and T1–2 pedicle screws bilaterally, possible spinous process wires at C5–6 if poor bone quality, seat rods in screws and apply caps with little extra rod proximally if fusion construct needs to be extended, harvest iliac crest bone graft, irrigate cervical wound, decorticate exposed posterior bone, pack cancellous bone graft over decorticated bone, layered closure with subfascial drain Position prone in neutral neck position with attention to angle of gaze, mark midline incision based on anatomical landmarks, midline posterior incision, dissect to posterior elements in midline avascular plane, x-ray to localize, expose C2-T2, navigation spin, drill bilateral lateral mass pilot holes from C3-C6 using Magerl technique and likely skip C7, navigate pilot holes and place pedicles screws at C2 and T1-T2, confirm placement of pedicle screws with O-arm spin, place rods, decorticate exposed bony surfaces and pack allograft generously, layered closure with subfascial drain, place vancomycin powder epifascially Position supine, approach based on vocal cord analyses, remove nasopharyngeal tube to avoid more compression once esophagus is localized, use previous plate without fluoroscopy to determine levels, remove plate, prepare disc spaces as usual using Caspar distractor, cage test and select seize, cages filled with allograft bone—do this at C2–3, C5–6, and C6–7, close with drain
Complication avoidance Anterior approach Preflip IOM, skip instrumentation at C7 to facilitate rod placement, possible spinous process wires to augment fusion, leave proximal rod a little longer for potential future surgery Magerl technique for lateral mass screws, skip instrumentation at C7, surgical navigation for pedicle screws Anterior approach, side of approach based on vocal cord assessment, have in mind the previous surgery
Postoperative
Admission ICU Floor Floor Floor
Postoperative complications feared Dysphagia, hematoma Wound infection, hematoma, adjacent segment disease Hardware failure, pseudoarthrosis, adjacent level disease Dysphagia, dystonia, hematoma
Anticipated length of stay 2 days 2–3 days 3–4 days 2 days
Follow-up testing

  • C-spine x-ray after surgery, 1 and 3 months after surgery

  • C-spine CT 6 months after surgery

  • CT C-spine prior to discharge

  • C-spine x-rays 6 weeks

  • C-spine flexion/extension x-rays at 3 months, 6 months, 12 months, 24 months after surgery

  • Vitamin D levels annually

Cervical and thoracic AP/Lateral X-rays at 2 weeks, 6 weeks, and as needed follow-up C-spine x-rays after surgery, 1 month, 3 month, and 6 months after surgery
Bracing Philadelphia collar for 2 weeks Aspen collar for 6 weeks None Soft collar for 3 weeks
Follow-up visits 7 days, 1 month, 3 months, and 6 months after surgery 2 weeks, 6 weeks, 3 months, 6 months, 12 months, 24 months after surgery 2 weeks, 6 weeks, and as needed follow-up after surgery 1 month, 3 months, and 6 months after surgery
CBC , Complete blood count; CRP , C-reactive protein; CT , computed tomography; DEXA , dual-energy x-ray absorptiometry; ESR , erythrocyte sedimentation rate; IOM , intraoperative monitoring; MAP , mean arterial pressure; MEP , motor evoked potential; NSAIDs , nonsteroidal antiinflammatory drugs; PEEK , polyetheretherketone; SSEP , somatosensory evoked potential.

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