Cervical Spine Deformity Correction Techniques

Abstract

Cervical kyphotic deformity can be a debilitating condition with symptoms ranging from mechanical neck pain, radiculopathy, and myelopathy to impaired swallowing and horizontal gaze. Surgical correction of cervical kyphosis has the potential to halt progression of neurological and clinical deterioration and even restore function. There are various operative approaches and deformity correction techniques. Choosing the optimal strategy is predicated on a fundamental understanding of spine biomechanics. Preoperative characterization of cervical malalignment, assessment of deformity rigidity, and defining postoperative clinical and radiographic objectives are paramount to formulating a surgical plan that balances clinical benefit with morbidity. This review of cervical deformity treatment provides an overview of the biomechanics of cervical kyphosis, radiographic classification, algorithm-based management, surgical techniques, and current surgical outcome studies.

Keywords: Cervical deformity; Cervical spine; Corpectomy; Kyphosis; Osteotomy; Spinal fusion.

Fig. 1.

Cranial center of mass (CCOM) denoted by the dot on the line bisecting the nasion-inion midsagittal line demonstrating the force vector on the cervical spine in flexion, neutral alignment, and extension.

Fig. 2.

Artist rendering demonstrating radiographic parameters used to define cervical sagittal alignment parameters. Cervical sagittal vertical alignment demonstrated as the distance between the C7 postero-superior endplate and a plumb line from the C2 centroid. T1 slope denoted as the angle between the extension of the T1 superior endplate and the horizontal reference line through the midpoint of the T1 superior endplate. Thoracic inlet angle represented as the angle between the extension of the T1 superior endplate line connected to the sternum and a reference line orthogonal to the midpoint of the T1 superior endplate. Neck tilt denoted as the angle between the line parallel to the T1 superior endplate and the vertical reference line.

Fig. 3.

Chin-brow vertical angle denoted as the angle subtended between the vertical axis and a line connecting the chin-to-brow.

Fig. 4.

Algorithm to assist with operative decision-making for cervical deformity. ACF, anterior cervical corpectomy and fusion; ACDF, anterior cervical discectomy and fusion; AO, anterior osteotomy; PSO, pedicle subtraction osteotomy; SPO, Smith Peterson Osteotomy; VCR, vertebral column resection.

Fig. 5.

A 63-year-old male who presented with progressive cervical myelopathy and acute-on-chronic quadriparesis. (A, B) Preoperative lateral X-ray and computed tomography scan demonstrating severe cervical kyphosis. (C) Preoperative sagittal magnetic resonance imaging demonstrating spinal cord compression and T2 signal abnormality within the cord. The patient underwent multilevel anterior cervical discectomy and fusion from C2 to C7 to correct the kyphotic deformity, as well as, C2-T1 posterolateral instrumented fusion and decompression. (D, E) Postoperative anteroposterior and lateral radiographs demonstrating deformity correction.

Fig. 6.

A 50-year-old female with chin-on-chest deformity and complete collapse of the C4 and C5 vertebral bodies secondary to osteomyelitis. The patient had significant upper extremity weakness and profound weight loss due to severe dysphagia. (A) Preoperative sagittal computed tomography demonstrating severe kyphotic deformity centered at C4–5. The deformity was nonrigid and the patient was placed in halo traction for gradual reduction (B). (C) Post traction, preoperative magnetic resonance imaging demonstrating cervical stenosis and destruction of the C4 and C5 vertebral bodies. The patient underwent 2 level (C4–5) anterior corpectomy and fusion supplemented with C2-T2 posterior instrumented fusion (D, E).

Fig. 7.

A 33-year-old male after motor vehicle accident several months prior presented with worsening neck pain and bilateral arm paresthesias with imaging findings of cervical kyphosis. Panel A demonstrates lateral upright cervical X-ray with midcervical kyphotic deformity. (B) Sagittal T2 magnetic resonance imaging demonstrating erosive changes throughout the midcervical spine and loss of disc height resulting in cervical kyphosis. (C) Deformity was reduced with cervical traction and patient was secured preoperatively with a halo vest. (D, E) Postoperative anteroposterior and lateral upright cervical X-rays after C2-T2 posterior cervicothoracic instrumentation and fusion demonstrating restoration of cervical lordosis.

Fig. 8.

A 73-year old male with Parkinson disease and remote history of anterior cervical discectomy and fusion (ACDF) who underwent recent posterior cervical spine surgery at another facility. He presented with new postoperative worsening kyphosis and chin-on-chest deformity. (A) Lateral upright cervical spine X-ray demonstrating prior ACDF and recent posterior cervical instrumentation with failure of lateral mass screw and sublaminar hook and rod construct. (B) He was placed in cervical traction and secured with a halo vest, with incomplete reduction of his kyphosis. (C, D) Postoperative upright cervical anteroposterior/lateral X-rays after undergoing removal of previous posterior cervical hardware, Ponte osteotomies at C2/3, C3/4, C5/6, C6/7, and C7/T1, and occipital-thoracic posterior instrumentation and fusion.

Fig. 9.

A 66-year-old male with history of ankylosing spondylitis. (A-C) He suffered minor trauma and subsequently developed chin-on-chest deformity secondary to fracture of the C7 vertebral body as demonstrated on preoperative sagittal computed tomography (CT), lateral radiograph, and magnetic resonance imaging. In the setting of diffuse ankylosis, he underwent a posterior opening wedge osteotomy at C6 with posterior fixation of C2 to T3. Panel D demonstrates immediate postoperative X-ray with corrected sagittal alignment and posterior instrumented stabilization. (E) Midsagittal CT demonstrating deformity correction at the C6 vertebral body with anterior osteoclastic opening wedge osteotomy.

Fig. 10.

A 59-year-old female who underwent posterior decompression and fusion from C4 to C6 for spinal epidural abscess and osteomyelitis at another facility. (A) She subsequently presented with cervicothoracic junction kyphosis with chin-on-chest deformity. (B, C) Preoperative sagittal computed tomography and magnetic resonance imaging demonstrating a fixed deformity, positive sagittal imbalance, and spinal cord compression secondary to ventral spinal cord compression. The patient underwent a posterior approach for C7 pedicle subtraction osteotomy with posterior segmental instrumentation from C2 to T3. (D, E) Postoperative anteroposterior and lateral radiographs demonstrating posterior instrumented fusion and sagittal deformity correction.