A Radiographic Analysis of Cervical Sagittal Alignment in Adolescent Idiopathic Cervical Kyphosis

Correlation between C7-T1 Intervertebral Foramen Area and Sagittal Parameters in Patients with Cervical Spondylotic Myelopathy

Objective

Cervical spondylotic myelopathy (CSM) is an incomplete spinal cord injury characterized with pain and stiffness in the neck and motor and sensory dysfunction. This study aims to determine whether C7–T1 intervertebral foramen area could be used as a parameter to evaluate the sagittal curvature of cervical spine.

Methods

Patients with clinical manifestations of spinal cord compression were hospitalized in our hospital from September 2018 to August 2019. All patients were diagnosed with CSM by nuclear magnetic imaging and other imaging methods. C2–C7 Cobb angle and T1 slop (T1S) were measured on the sagittal, T2‐weighted magnetic resonance image of cervical spine, and C7–T1 intervertebral foramen area were measured using oblique cervical spine X‐rays. Patients were divided into two groups according to the value of C2–C7 Cobb angle, including lordosis group (C2–C7 Cobb angle >10°, n = 45) and straight group (C2–7 Cobb angle ≤10°, n = 55). The reliability of the data was evaluated by intraclass correlation coefficient (ICC), and the correlation of the imaging parameters was analyzed by Pearson correlation.

Results

A total of 100 patients diagnosed with CSM hospitalized in our department were included. The ICC of the cervical parameters was 0.73. C7–T1 intervertebral foramen area was 40.69 ± 11.44 and 39.95 ± 10.94 mm² in lordosis and straight group, respectively. The results showed that C7–T1 intervertebral foramen area was positively correlated with both C2–C7 Cobb angle (r = 0.23, p = 0.02) and T1S (r = 0.21, p = 0.03). In lordosis group, there was a positive correlation between C7 and T1 intervertebral foramen area and C2–C7 Cobb angle (r = 0.69, p < 0.01) and T1S (r = 0.34, p = 0.02). However, in straight group, C7–T1 intervertebral foramen area was not correlated with either C2–C7 Cobb angle or T1S.

Conclusion

C7–T1 intervertebral foramen area measured by oblique X‐ray could be an effective method to evaluate the sagittal balance of cervical vertebrae for CSM patients with cervical lordosis.

Progressive Adolescent Idiopathic Cervical Kyphosis Secondary to Constant Postural Neck Flexion Reading Habit with a 10-year Follow-up: Case Report and Literature Review

BACKGROUND

Although it has been established that adolescent idiopathic cervical kyphosis (AICK) has no known cause, there are associated risk factors. However, the underlying causes remain puzzling. This case report presents severe AICK linked to chronic neck flexion postural habit, treated with combined anterior and posterior correction surgery and review of the literature.

CASE PRESENTATION

A 16-year-old male with no history of trauma, surgery, or family history of spinal deformity complained of intolerable neck pain and rigidity. He developed an incessant reading of comic books at a very young age, and he preferred placing the book on the floor with his head flexed between his thighs. Acupuncture and massage therapy failed to relief symptoms. He had no neurological symptoms on examination and X-ray showed Cobb angle of 70.5°. MRI and CT scans showed no spinal cord compression or osteophyte formation. A combined anterior and posterior correction surgery was performed after a week of skull traction. The deformity was corrected, neck pain disappeared, and neck rotatory function maintained after posterior implant removal. The maximum follow-up was 10 years.

CONCLUSIONS

The potential underlying risk factor observed in this case is unusual. Chronic neck flexion postural habit is a potential risk factor of severe AICK in some individuals.

Apoptosis of endplate chondrocytes in cervical kyphosis is associated with chronic forward flexed neck: an in vivo rat bipedal walking model

BACKGROUND

This study was undertaken to establish a rat bipedal walking model of cervical kyphosis (CK) associated with chronic forward flexed neck and assess the effects of chronic forward flexed neck on endplate chondrocytes.

METHODS

Forty-eight 1-month-old Sprague-Dawley rats were randomly divided into 3 groups: forward flexed neck group (n = 16), bipedal group (n = 16), and normal group (n = 16). Cervical curves were analyzed on a lateral cervical spine X-ray using Harrison's posterior tangent method before the experiment and at 2-week intervals for a 6-week period. Histologic changes in cartilaginous endplate chondrocytes were observed using hematoxylin and eosin (H&E) staining, transmission electron microscopy (TEM), and terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP nick-end labeling.

RESULTS

Radiographic findings suggested a significantly decreased cervical physiological curvature in the forward flexed neck group over the 6-week follow-up; normal cervical curves were maintained in other groups. The average cervical curvature (C2-C7) was - 7.6 ± 0.9° in the forward flexed neck group before the experiment, - 3.9 ± 0.8° at 2 weeks post-experiment, 10.7 ± 1.0° at 4 weeks post-experiment, and 20.5 ± 2.1° at the last follow-up post-experiment. Histologically, results of H&E staining unveiled that cartilaginous endplate chondrocytes were arranged in an irregular fashion, with the decreased number at the observation period; the incidence of apoptotic cells in the forward flexed neck group was noticeably higher at the 6-week follow-up than that in other groups.

CONCLUSIONS

CK developed as the result of chronic forward flexed neck. Histologic changes suggested that chondrocyte apoptosis may play a critical role in the development of cervical kyphotic deformity associated with chronic forward flexed neck.

Preoperative and Intraoperative Skull Traction Combined with Anterior-Only Cervical Operation in the Treatment of Severe Cervical Kyphosis (>50 Degrees)

OBJECTIVE

To evaluate the clinical and radiographic outcomes of an anterior-only approach for the correction of severe cervical kyphotic deformities.

METHODS

We performed a retrospective study of 33 consecutive patients with severe cervical kyphosis treated with an anterior cervical operation and preoperative and intraoperative skull traction. Cobb angle, kyphosis index (KI), kyphosis level, C2-7 sagittal vertical axis (SVA), and T1 slope were measured. The preoperative and postoperative Japanese Orthopedic Association (JOA) scores, visual analog scale (VAS) score for neck pain, Neck Disability Index (NDI) scores, and cervical alignment were compared.

RESULTS

The mean angle of the kyphosis was 83.2 ± 20.4°. The mean Cobb angle of the operative region was 71.7 ± 18.5° preoperation, which was reduced to 10.6 ± 5.7° postoperation (mean correction, 85.2%). The mean KI was 75.1 ± 18.2 preoperation, which was reduced to 14.4 ± 9.1 postoperation (mean correction, 80.8%). The preoperative and postoperative mean C2-7 Cobb angle was 53.8 ± 16.5° and 14.7 ± 7.6°, respectively. The preoperative and postoperative mean C2-7 SVA was 3.9 ± 14.5 mm and 12.8 ± 7.3 mm, respectively. The preoperative and postoperative mean T1 slope was -9.4 ± 15.7° and 7.3 ± 13.1°, respectively. The average postoperative C2-7 Cobb angle, Cobb angle of the operative region, KI, C2-7 SVA, and T1 slope changed significantly compared with preoperative values (P < 0.05). The average postoperative JOA, VAS, and NDI scores improved significantly compared with preoperative scores (P < 0.05).

CONCLUSIONS

Preoperative and intraoperative skull traction combined with anterior-only cervical operation may be a safe and effective technique for treating severe cervical kyphosis. If the postoperative correction is >80%, sufficient decompression could be achieved.

Clinical outcomes of anterior correction and reconstruction for neurofibromatosis-associated severe cervical kyphotic deformity

PURPOSE

To assess the clinical outcome of anterior correction and reconstruction for severe cervical kyphotic deformity due to neurofibromatosis type 1 (NF-1).

METHODS

In this study, we reviewed a series of seven patients who underwent anterior procedures for correction of NF-1-associated cervical kyphotic deformity. After continuous preoperative skull traction, all patients received anterior corpectomy and fusion (ACCF), anterior discectomy and fusion (ACDF), or combined ACCF and ACDF for surgical correction and reconstruction. Pre- and postoperative local and global Cobb angles, correction rate, sagittal vertical axis (SVA), and T1-slope were assessed by X-ray. Japanese Orthopaedic Association (JOA) score, JOA recovery rate, visual analog scale (VAS), and Neck Disability Index (NDI) scores were recorded to assess the outcome.

RESULTS

Kyphosis was corrected successfully in all patients in terms of local and global Cobb angles (P < 0.05), with a correction rates of 83.1% (range, 66.0 to 115.5%) and 88.6% (range, 61.1 to 125.0%), respectively. JOA scores of patients were improved from preoperative 10.4 (range, 6 to 14) to postoperative 15.4 (range, 14 to 17), with a recovery rate as 77.6% (range, 66.7 to 100%). NDI scores were reduced from preoperative 25.1 (range, 13 to 35) to postoperative 8.7 (range, 5 to 12). VAS scores were reduced from preoperative 7.0 (range, 4 to 9) to postoperative 2.3 (range, 1 to 3).

CONCLUSION

This study has demonstrated that anterior correction and reconstruction is an alternative option for the treatment of NF-1-associated severe cervical kyphosis when deformity is localized, flexible, or fixed.