Prevalence and Predictive Factors of Concurrent Cervical Spinal Cord Compression in Adult Spinal Deformity

Takayoshi Shimizu, MD, PhD; Ronald A. Lehman Jr, MD; Suthipas Pongmanee, MD; J. Alex Sielatycki, MD; Eric Leung, BA; K. Daniel Riew, MD; Lawrence G. Lenke, MD

Disclosures

Spine. 2019;44(15):1049-1056. 

In This Article

Results

Demographics and Radiographic Analysis

Overall, the inter-rater reliability for radiographic measurements was excellent (ICCs 0.880–0.981).

Table 2 shows the patient characteristics and radiographic parameters. The mean age was 55.3 ± 14.1 (range, 23–82) years, with BMI of 24.4 ± 4.5 kg/m2, and female participants were the dominant group (M/F, 22:99). Etiologies were adult idiopathic (56.1%), degenerative kypho-scoliosis (23.9%), fixed sagittal imbalance syndrome (15.7%), Scheuermann's kyphosis (1.6%), postfracture kyphosis (1.6%), and ankylosing spondylitis (0.8%). Radiographic parameters demonstrated significant thoracic and thoracolumbar curvature in the coronal plane (main thoracic, 40.3 ± 27.1°; Lumbar/Thoracolumbar, 45.0 ± 25.1°) and slight sagittal malalignment (PI-LL mismatch, 8.5 ± 23.7°; C7SVA, 46.0 ± 89.7 mm; TPA, 21.7 ± 14.8°; and GSA, 3.5 ± 5.9°). The Torg-Pavlov ratio at the narrowest level was 1.0 ± 0.1, and three patients had <0.8 ratio. OPLL was observed in three patients (2.4%) with Grade 2 CCI.

Prevalence of Cervical Cord Compression

The inter-rater reliability for grading CCI was moderate (Cohen's κ = 0.701, 95% CI [0.679–0.721]). Table 3 shows the overall incidence of CSCC. Of 121 patients with ASD, 41 patients (33.8%) demonstrated significant CSCC (32 with Grade 2 and 9 with Grade 3). Cord signal change (myelomalacia) on T2-weighted imaging was present in eight patients (6.6%). Significant CSCC was most commonly observed at the C4/5 level (Figure 1). Among the 41 patients with significant CSCC, 22 patients had one-level cord compression, while the remaining 19 patients had more than two-level cord compressions (Figure 2). In addition, 35 of 41 patients (85.3%) were asymptomatic or with myelopathy that is difficult to detect (e.g., subtle Hoffman reflex), while 6 of 41 patients were myelopathic (e.g., hyperreflexia of lower extremities and weakness/atrophy in upper extremities).

Figure 1.

Distribution of cervical cord compression level.

Figure 2.

Number of patients presenting cervical cord compression with cord compression index (CCI) Grade >2.

Table 4 shows the distribution of CSCC according to each age generation. Significant CSCC was commonly seen even in patients in their 30s (37.5%) and significantly prevalent in those aged over 70s. Prior to the thoracolumbar reconstruction surgery, four patients (3.3%) underwent cervical decompression and fusion; in these patients, three had Grade 3 CSCC, of which two patients showed cord signal change (Figure 3A–E), whereas the other one had Grade 2 CSCC with OPLL. The multivariate regression analysis revealed that age (P = 0.034), BMI (P < 0.01), and PI-LL mismatch (P < 0.01) independently predicted the CSCC grade (Table 5).

Figure 3.

A 70-year-old female with fixed sagittal balance syndrome undergoing cervical spine surgery (C2-T1 anterior and posterior fusion) prior to thoracolumbar reconstruction (T10-Sacrum/Pelvis). Physical examination showed slight weakness in upper extremities. (A, B) Preoperative cervical and thoracolumbar X-ray showing 42.2° of PI-LL mismatch. (C) Postoperative whole-spine X-ray after thoracolumbar reconstruction, (D, E) preoperative cervical MRI showing multiple cord compression and Grade 3 Cord Compression Index at C3/4.

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