Gap between flexion and extension ranges of motion: a novel indicator to predict the loss of cervical lordosis after laminoplasty in patients with cervical spondylotic myelopathy

J Neurosurg Spine 35:8–17, 2021

Kyphotic deformity resulting from the loss of cervical lordosis (CL) is a rare but serious complication after cervical laminoplasty (CLP), and it is essential to recognize the risk factors. Previous studies have demonstrated that a greater flexion range of motion (fROM) and smaller extension ROM (eROM) in the cervical spine are associated with the loss of CL after CLP. Considering these facts together, one can hypothesize that an indicator representing the gap between fROM and eROM (gROM) is highly useful in predicting postoperative CL loss. In the present study, the authors aimed to investigate the risk factors of marked CL loss after CLP for cervical spondylotic myelopathy (CSM), including the gROM as a potential predictor.

METHODS Patients who had undergone CLP for CSM were divided into those with and those without a loss of more than 10° in the sagittal Cobb angle between C2 and C7 at the final follow-up period compared to preoperative measurements (CL loss [CLL] group and no CLL [NCLL] group, respectively). Demographic characteristics, surgical information, preoperative radiographic measurements, and posterior paraspinal muscle morphology evaluated with MRI were compared between the two groups. fROM and eROM were examined on neutral and flexion-extension views of lateral radiography, and gROM was calculated using the following formula: gROM (°) = fROM − eROM. The performance of variables in discriminating between the CLL and NCLL groups was assessed using the receiver operating characteristic (ROC) curve.

RESULTS This study included 111 patients (mean age at surgery 68.3 years, 61.3% male), with 10 and 101 patients in the CLL and NCLL groups, respectively. Univariate analyses showed that fROM and gROM were significantly greater in the CLL group than in the NCLL group (40.2° vs 26.6°, p < 0.001; 31.6° vs 14.3°, p < 0.001, respectively). ROC curve analyses revealed that both fROM and gROM had excellent discriminating capacities; gROM was likely to have a higher area under the ROC curve than fROM (0.906 vs 0.860, p = 0.094), with an optimal cutoff value of 27°.

CONCLUSIONS The gROM is a highly useful indicator for predicting a marked loss of CL after CLP. For CSM patients with a preoperative gROM exceeding 30°, CLP should be carefully considered, since kyphotic changes can develop postoperatively.

Skip Laminectomy Compared with Laminoplasty for Cervical Compressive Myelopathy

World Neurosurg. (2018) 120:296-301

This meta-analysis evaluated the clinical outcomes of skip laminectomy relative to laminoplasty for the treatment of cervical compressive myelopathy.

METHODS: The Cochrane library, PubMed MEDLINE, EMBASE, and Web of Science databases were comprehensively searched to identify relevant articles published up to March 18, 2018. All values of weighted mean difference (WMD) or odds ratio are expressed as skip laminectomy relative to laminoplasty.

RESULTS: Four studies comprising 241 patients were included. Skip laminectomy and laminoplasty were comparable in terms of cervical lordotic curvature (weighted mean difference [WMD] L2.37; 95% confidence interval [CI] L6.18 to 1.43; P [ 0.22) and range of motion (WMD e2.65; 95% CI L6.02 to 0.72; P [ 0.12). The pooled data revealed that the mean visual analogue scale score for pain of the skip laminectomy group was significantly lower than that of the laminoplasty group (WMD e0.97; 95% CI L1.90 to L0.05; P [ 0.04), and the rate of axial pain was also significantly lower (WMD 0.26; 95% CI 0.07e0.93; P [ 0.04). The atrophy rates of the deep extensor muscles in the skip laminectomy group (14%) were significantly lower than that of the laminoplasty group (60%).

CONCLUSIONS: This meta-analysis determined that skip laminectomy was superior to laminoplasty in terms of visual analogue scale score and rates of axial pain and muscle atrophy. These results warrant further confirmation in future research.

Simple presurgical method of predicting C5 palsy after cervical laminoplasty using C5 nerve root ultrasonography

J Neurosurg Spine 29:365–370, 2018

The incidence of C5 palsy after cervical laminoplasty is approximately 5%. Because C5 palsy is related to cervical foraminal stenosis at the C4–5 level, the authors hypothesized that cervical foraminal stenosis can be diagnosed by examining the C5 nerve root (NR) using ultrasonography. The purpose of this study was to investigate whether postoperative C5 palsy could be predicted using ultrasonography.
METHODS This study used a prospective diagnosis design. In total, 140 patients undergoing cervical laminoplasty were examined with ultrasound. The cross-sectional area (CSA) of the C5 NR was measured on both sides before surgery, and the incidence of postoperative C5 palsy was examined. The difference between the CSA of the patients with and without C5 palsy and the lateral differences in the C5 palsy group were determined.
RESULTS The incidence of C5 palsy was 5% (7 cases). Symptoms manifested at a median of 5 days after surgery (range 1–29 days). The CSA of the C5 NR on the affected side was significantly enlarged in the C5 palsy group compared with that in the no–C5 palsy group (p = 0.001). In addition, in the patients who had C5 palsy, the CSA of the C5 NR was significantly enlarged on the affected side compared with that on the unaffected side (p = 0.02). Receiver operating characteristic analysis indicated that the best threshold value for the CSA of the C5 NR was 10.4 mm2 , which provided 91% sensitivity and 71% specificity.
CONCLUSIONS C5 palsy may be predicted preoperatively using ultrasound. The authors recommend the ultrasonographic measurement of the CSA of the C5 NR prior to cervical laminoplasty.

Open-versus French-Door Laminoplasty for the Treatment of Cervical Multilevel Compressive Myelopathy: A Meta-Analysis

World Neurosurg. (2018) 117:129-136

OBJECTIVE: To compare the clinical outcomes and postoperative complications between open-door laminoplasty (ODL) versus French-door laminoplasty (FDL) for the treatment of cervical multilevel compressive myelopathy.

METHODS: We comprehensively searched PubMed, EMBASE, Cochrane library, and China National Knowledge Infrastructure to identify relevant articles. The search results were last updated on January 1, 2018. All values of weighted mean difference (WMD) and odds ratio are expressed as ODL relative to FDL.

RESULTS: Six studies containing 430 patients were included in our metaanalysis. In randomized controlled trials, there was no significant difference in Japanese Orthopaedic Association (JOA) scores between ODL and FDL groups (WMD, 0.06; 95% confidence limits [CL], e0.52 to 0.64; P [ 0.84). However, in the retrospective trials, JOA scores were significantly higher in the ODL group than in the FDL group (WMD, 0.95; 95% CL, 0.55e1.34; P < 0.05). The pooled data showed that the magnitude of spinal canal expansion in the ODL group was higher than in the FDL group (WMD, 24.39%; 95% confidence interval, 12.33e36.45; P < 0.05).

CONCLUSIONS: The present meta-analysis showed that the magnitude of canal expansion was higher with ODL than with FDL. There is a lack of compelling evidence to prove the superiority of one procedure over the other.

Cervical Laminectomy vs Laminoplasty: Is There a Difference in Outcome and Postoperative Pain?

Neurosurgery 70:965–970, 2012 DOI: 10.1227/NEU.0b013e31823cf16b 

Cervical laminoplasty is often used for the decompression of multilevel cervical spondylotic myelopathy without creating spinal instability and kyphosis.

OBJECTIVE: To assess the axial pain, quality of life, sagittal alignment, and extent of decompression after standard cervical laminectomy or laminoplasty. We further evaluate whether the sagittal alignment changes over time after both procedures and whether axial pain depends on sagittal alignment.

METHODS: We reviewed 268 patients with cervical radiculopathy or myelopathy who had undergone standard cervical laminectomy or laminoplasty between January 1999 and January 2009. The clinical outcome was analyzed by visual analog scale for neck pain. The quality of life was analyzed by EQ-5D questionnaire. The degree of deformity and extent of decompression were assessed using the Ishihara index and Pavlov’s ratio, respectively.

RESULTS: Laminoplasty was associated with more neck pain and worse quality of life when 4 or more levels were decompressed compared with the laminectomy group. For operations of 3 or fewer levels, there was no difference. Interestingly, the radiological effectiveness of decompression was greater in the laminoplasty group.

CONCLUSION: Laminoplasty for 4 or more cervical levels was associated with more axial pain and consequently poorer quality of life than laminectomy. There was a similar loss of sagittal alignment in both the laminectomy and laminoplasty groups over time. Our results suggest there is no clear benefit of laminoplasty over laminectomy in patients who do not have spinal instability.