The Impact of Standing Regional Cervical Sagittal Alignment on Outcomes in Posterior Cervical Fusion Surgery

Department of Neurological Surgery, University of California, San Francisco, San Francisco, California 94143, USA.
Neurosurgery (Impact Factor: 3.03). 05/2012; 71(3):662-9; discussion 669. DOI: 10.1227/NEU.0b013e31826100c9
Source: PubMed

ABSTRACT Positive spinal regional and global sagittal malalignment has been repeatedly shown to correlate with pain and disability in thoracolumbar fusion.
To evaluate the relationship between regional cervical sagittal alignment and postoperative outcomes for patients receiving multilevel cervical posterior fusion.
From 2006 to 2010, 113 patients received multilevel posterior cervical fusion for cervical stenosis, myelopathy, and kyphosis. Radiographic measurements made at intermediate follow-up included the following: (1) C1-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (C2-C7 SVA; distance between C2 plumb line and C7), (4) center of gravity of head SVA (CGH-C7 SVA), and (5) C1-C7 SVA. Health-related quality-of-life measures included neck disability index (NDI), visual analog pain scale, and SF-36 physical component scores. Pearson product-moment correlation coefficients were calculated between pairs of radiographic measures and health-related quality-of-life scores.
Both C2-C7 SVA and CGH-C7 SVA negatively correlated with SF-36 physical component scores (r = -0.43, P < .001 and r = -0.36, P = .005, respectively). C2-C7 SVA positively correlated with NDI scores (r = 0.20, P = .036). C2-C7 SVA positively correlated with C1-C2 lordosis (r = 0.33, P = .001). For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of approximately 40 mm, beyond which correlations were most significant.
Our findings demonstrate that, similar to the thoracolumbar spine, the severity of disability increases with positive sagittal malalignment following surgical reconstruction.

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    ABSTRACT: Study Design. Retrospective comparative study.Objective. To analyze changes in the clinical and radiological factors related to cervical sagittal balance, relative to preoperative T1 slope, in patients with cervical myelopathy following laminoplasty.Summary of Background Data. T1 slope is an important factor that should be considered before laminoplasty. However, until now there have been no studies on how preoperative T1 slope affects the sagittal balance of cervical spine and various functional outcomes following laminoplasty.Methods. Seventy-six cervical myelopathy patients (M:F ratio = 50:26; mean age = 64.7 ± 9.1 years) received a cervical laminoplasty and were followed > 2 years. Radiological measurements were performed to analyze the following parameters: (1) C2-C7 sagittal vertical axis; (2) T1 slope; (3) C2-C7 lordosis; and (4) thoracic kyphosis. The visual analogue scale (VAS), JOA, neck disability index (NDI), and SF-36 were also investigated. Patients were divided into two groups according to preoperative T1 slope, with the cut-off value being the median preoperative T1 slope. Changes in clinical and radiological parameters were compared between the preoperative evaluation and final visit.Results. Overall, C2-C7 SVA increased from 21.2 to 24.5 mm (p = 0.004) and C2-C7 lordosis decreased from 13.9° to 10.3° (p = 0.007) postoperatively. The T1 slope did not show any postoperative differences. Preoperative C2-C7 lordosis was larger in the high-T1 group (19.1°) than in the low-T1 group (9.0°). However, postoperative changes in C2-C7 SVA and C2-C7 lordosis did not show any between-group differences. Clinical outcomes (except neck pain) demonstrated overall improvement in both groups. Comparing changes in both groups showed no differences in neck pain, arm pain, NDI, or SF-36 PCS between groups.Conclusions. Cervical sagittal balance is compromised following cervical laminoplasty. However, the degree of aggravation does not correlate with the preoperative T1 slope. Most clinical parameters demonstrate overall improvement regardless of preoperative T1 slope.
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May 28, 2014