Neurological Evaluation of Severe Congenital Kyphosis With Compressive Myelopathy in 39 Patients With a Minimum 1-Year Follow-Up

Abstract

Objective: Congenital angular kyphosis with compressive myelopathy is a rare yet underreported neurologic emergency for spine surgeons. The study aimed to report the neurological outcomes of 39 patients with compressive myelopathy in congenital kyphosis (CK) and provide magnetic resonance imaging (MRI) features in these patients, identifying the potential prognostic factors.

Methods: This is a retrospective cohort study. From January 2010 to December 2022, 39 patients were diagnosed with severe congenital angular kyphosis with compressive myelopathy and received surgical correction. The American Spinal Injury Association (ASIA) Impairment Scale grades at admission and final follow-up were recorded to measure neurological outcomes. A series of qualitative and quantitative parameters were evaluated on preoperative MRI by observers who were blinded to the clinical outcomes. According to the final status of neurological recovery, patients were divided into two groups and compared: Group E (patients with ASIA E) and Group N (patients with ASIA A, B, C, and D).

Results: At the final follow-up, 79.5% of patients (31 cases) had improved neurological function and myelopathy symptoms. The average Cobb angle of kyphosis decreased from 78.4° to 20.1° after correction surgery. The duration of myelopathy in Group N was significantly longer than that in Group E (p = 0.038). T1-weighted imaging (T1WI) signal hypointensity was presented in 35.9% (14/39) of patients, and T2-weighted imaging (T2WI) signal hyperintensity was 69.2% (27/39). On average, these patients had a maximum canal compromise (MCC) of 52.2%, maximum spinal cord compression (MSCC) of 47.0%, and maximum transverse area compression (MTAC) of 49.1%. Compared to Group E, Group N showed greater MCC (p = 0.023), MSCC (p = 0.008), and MTAC (p < 0.001) at baseline, and was more likely to present T1WI hypointensity and T2WI hyperintensity. The cut-off values of MTAC, MCC, and MSCC for fully neurological recovery were 47.1%, 46.7%, and 52.6%, respectively.

Conclusion: MRI indicators of poor prognosis in CK patients with compressive myelopathy included the presence of T1WI hypointensity, T2WI hyperintensity, and greater MCC, MSCC, and MTAC. It was suggested that early surgical intervention is critical to prevent irreversible cord injury, particularly in patients with MTAC > 47.1%.

Keywords: compressive myelopathy; congenital angular kyphosis; magnetic resonance imaging; neurological dysfunction.

FIGURE 1

This bar graph shows postoperative changes of ASIA Grade among patients.

FIGURE 2

This line graph presents the average values of MSCC, MCC, and MTAC of patients with different ASIA Grades.

FIGURE 3

This 38‐year‐old woman of congenital thoracolumbar kyphosis had a severe and angular kyphotic apex at T12/L1, with a preoperative ASIA D Grade. (A, B) Plain radiograms showing angular congenital kyphosis at T12/L1 and roughly coronal and sagittal balance. (C) Three‐dimensional CT image reconstruction showing developmental vertebral anomalies from T12 to L2. (D, E) Sagittal and axial MR images showing spinal cord deformation and compression at the apical region. (F, G) Plain radiograms showing corrected deformity after multilevel VCR (T12 and L1).

FIGURE 4

ROC curve to find the optimum cut‐off point of MTAC, MCC, and MSCC to predict postoperative neurological recovery.