The influence of sagittal profile alteration and final lordosis on the clinical outcome of cervical spondylotic myelopathy. A Delta-Omega-analysis

[Analysis of imaging characteristics and effectiveness of cervical spondylotic myelopathy with cervical kyphosis]

Objective

To investigate the imaging characteristics of cervical kyphosis and spinal cord compression in cervical spondylotic myelopathy (CSM) with cervical kyphosis and the influence on effectiveness.

Methods

The clinical data of 36 patients with single-segment CSM with cervical kyphosis who were admitted between January 2020 and December 2022 and met the selection criteria were retrospectively analyzed. The patients were divided into 3 groups according to the positional relationship between the kyphosis focal on cervical spine X-ray film and the spinal cord compression point on MRI: the same group (group A, 20 cases, both points were in the same position), the adjacent group (group B, 10 cases, both points were located adjacent to each other), and the separated group (group C, 6 cases, both points were located >1 vertebra away from each other). There was no significant difference between groups ( P>0.05) in baseline data such as gender, age, body mass index, lesion segment, disease duration, and preoperative C 2-7 angle, C 2-7 sagittal vertical axis (C 2-7 SVA), C 7 slope (C 7S), kyphotic Cobb angle, fusion segment height, and Japanese Orthopedic Association (JOA) score. The patients underwent single-segment anterior cervical discectomy with fusion (ACDF). The occurrence of postoperative complications was recorded; preoperatively and at last follow-up, the patients' neurological function was evaluated using the JOA score, and the sagittal parameters (C 2-7 angle, C 2-7 SVA, C 7S, kyphotic Cobb angle, and height of the fused segments) were measured on cervical spine X-ray films and MRI and the correction rate of the cervical kyphosis was calculated; the correlation between changes in cervical sagittal parameters before and after operation and the JOA score improvement rate was analyzed using Pearson correlation analysis.

Results

In 36 patients, only 1 case of dysphagia occurred in group A, and the dysphagia symptoms disappeared at 3 days after operation, and the remaining patients had no surgery-related complications during the hospitalization. All patients were followed up 12-42 months, with a mean of 20.1 months; the difference in follow-up time between the groups was not significant ( P>0.05). At last follow-up, all the imaging indicators and JOA scores of patients in the 3 groups were significantly improved when compared with preoperative ones ( P<0.05). The correction rate of cervical kyphosis in group A was significantly better than that in group C, and the improvement rate of JOA score was significantly better than that in groups B and C, all showing significant differences ( P<0.05), and there was no significant difference between the other groups ( P>0.05). The correlation analysis showed that the improvement rate of JOA score was negatively correlated with C 2-7 angle and kyphotic Cobb angle at last follow-up ( r=-0.424, P=0.010; r=-0.573, P<0.001), and positively correlated with the C 7S and correction rate of cervical kyphosis at last follow-up ( r=0.336, P=0.045; r=0.587, P<0.001), and no correlation with the remaining indicators ( P>0.05).

Conclusion

There are three main positional relationships between the cervical kyphosis focal and the spinal cord compression point on imaging, and they have different impacts on the effectiveness and sagittal parameters after ACDF, and those with the same position cervical kyphosis focal and spinal cord compression point have the best improvement in effectiveness and sagittal parameters.

Influence of Preoperative Sagittal Alignment on Functional Recovery in Operated Cases of Cervical Spondylotic Myelopathy

Objective  We examine the influence of preoperative cervical sagittal curvature (lordotic or nonlordotic) on the functional recovery of surgically managed cases of cervical spondylotic myelopathy (CSM). The impact of sagittal alignment on the functional improvement of operated CSM cases has not been thoroughly investigated. Materials and Methods  We did retrospective analysis of consecutively operated cases of CSM from March 2019 to April 2021. Patients were grouped into two categories: lordotic curvature (with Cobb angle > 10 degrees) and nonlordotic curvature (including neutral [Cobb angle 0-10 degrees] and kyphotic [Cobb angle < 0 degrees]). Demographic data, and preoperative and postoperative functional outcome scores (modified Japanese Orthopaedic Association [mJOA] and Nurick grade) were analyzed for dependency on preoperative curvature, and correlations between outcomes and sagittal parameters were assessed. Results  In the analysis of 124 cases, 63.1% (78 cases) were lordotic (mean Cobb angle of 23.57 ± 9.1 degrees; 11-50 degrees) and 36.9% (46 cases) were nonlordotic (mean Cobb angle of 0.89 ± 6.5 degrees; -11 to 10 degrees), 32 cases (24.6%) had neutral alignment, and 14 cases (12.3%) had kyphotic alignment. At the final follow-up, the mean change in mJOA score, Nurick grade, and functional recovery rate (mJOArr) were not significantly different between the lordotic and nonlordotic group. In the nonlordotic group, cases with anterior surgery had a significantly better mJOArr than those with posterior surgery ( p  = 0.04), whereas there was similar improvement with either approach in lordotic cases. In the nonlordotic group, patients who gained lordosis (78.1%) had better recovery rates than those who had lost lordosis (21.9%). However, this difference was not statistically significant. Conclusion  We report noninferiority of the functional outcome in the cases with preoperative nonlordotic alignment when compared with those with lordotic alignment. Further, nonlordotic patients who were approached anteriorly fared better than those approached posteriorly. Although increasing sagittal imbalance in nonlordotic spines portend toward higher preoperative disability, gain in lordosis in such cases may improve results. We recommend further studies with larger nonlordotic subjects to elucidate the impact of sagittal alignment on functional outcome.

The surgical strategy for multilevel massive ossification of the posterior longitudinal ligaments

Purpose

Creating enough decompression, favorable outcome, less complication, and maintain adequate lordosis and stability in the patients with cervical myelopathy due to multilevel massive ossification of the posterior longitudinal ligament (OPLL) still poses a challenge for surgeons. The aim of our study is to retrospectively evaluate our patients and try to seek a better surgical strategy.

Methods

Between 2015 and 2019, 55 consecutive patients with multilevel massive OPLL underwent surgical treatment. Among these, 40 patients were treated with cervical laminectomy and then anterior decompression, fusion, and fixation (ADF), which was defined as group 1, and 15 patients were treated with cervical laminectomy and fixation simultaneously, which was defined as group 2. The patient's radiographic characteristics and postoperative outcomes were evaluated.

Results

Better postoperative cervical sagittal lordosis and less long-term axial pain was achieved in group 1 (p < 0.001), though the functional outcome had no significant difference. In the multivariable analysis, anterior fixation accounts for independent factors for better cervical sagittal alignment (p < 0.001). No complications directly associated with cervical laminectomy were observed.

Conclusion

In patients with cervical multilevel massive OPLL, laminectomy at compression level and then ADF depended on the severity and range of compression, but corpectomy of not more than two vertebral bodies is suggested, except K-line (+) and long-segment massive OPLL majorly involving the C2 and posterior laminectomy above and below the OPLL-affected levels with posterior fixation simultaneously.

Cervical Sagittal Alignment in Patients with Cervical Spondylotic Myelopathy: An Observational Study From the Canadian Spine Outcomes and Research Network

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

Among patients with CSM, we aimed to evaluate the extent to which: (1) Preoperative cervical sagittal alignment is associated with health-related quality of life, function, and symptoms; (2) Surgery leads to changes in cervical sagittal alignment; and (3) Postoperative cervical sagittal alignment is associated with health-related quality of life, function, and symptoms at 12 months of follow-up.

SUMMARY OF BACKGROUND DATA

The importance of maintaining or improving cervical sagittal alignment in the surgical management of patients with CSM has not been established.

METHODS

We measured C2-C7 Cobb angle, T1 slope, and C2-C7 cervical sagittal vertical axis (cSVA). We tested for associations with Neck Disability Index, Pain Scales for neck and arm pain, EuroQol 5D, Short Form 12 Physical and Mental Component Summaries, and modified Japanese Orthopaedic Association scores. We adjusted for potential confounders using multiple linear regression, and we performed various prespecified subgroup (cSVA > 40 mm, surgical approach) and sensitivity analyses.

RESULTS

Among 250 patients, adjusted analyses yielded significant inverse associations prior to surgery between each of cSVA and T1 slope with SF12 Physical Component Summaries (T1 slope: -0.14, 95% CI -0.26 to -0.01, P = 0.03; C2-C7 cSVA: -0.13, 95% CI --0.21 to -0.05 P < 0.01). Surgery was associated with a small but statistically significant increase in cSVA across the cohort (+5.8 mm [SD 11.7], P < 0.01) but no change in Cobb angle or T1 slope. At 12-months after surgery, there were no significant associations between alignment parameters or change in alignment and any measures of health-related quality of life, function, or symptoms. Results were consistent across subgroup and sensitivity analyses.

CONCLUSION

Increased cSVA and T1 slope were associated with inferior health-related quality of life at presentation among patients with CSM, but no significant associations were observed following surgical treatment.Level of Evidence: 3.

Comparison of sagittal vertical axis and decompression on the clinical outcome of cervical spondylotic myelopathy

OBJECTIVE

Decompression and cervical balance are major goals in the surgical treatment of cervical spondylotic myelopathy (CSM). Cervical balance is assumed to be a key factor for neurological recovery and pain reduction. Surgical reduction of C2-7 sagittal vertical axis (SVA) correlates with clinical improvement. However, it remains unclear, how much or even if correction is necessary for clinical improvement as long as surgery results in successful decompression. We aim to evaluate the role of radiological cervical balance parameter on the short-term course of CSM.

METHODS

This is a retrospective study with prospectively collected data of 90 patients. The authors identified 45 patients suffering from CSM that underwent decompressive surgery and instrumentation and showed an increased C2-7 sagittal vertical axis (SVA) after surgery. 45 consecutive patients with a decreased C2-7 SVA were selected as a control group.

RESULTS

Surgery improved the clinical outcome of both groups significantly. No differences could be seen comparing neck pain and neurological improvement between both groups. An increased C2-7 SVA did not correlate with an inferior clinical outcome. T1-slope correlated with the Cobb-angle.

CONCLUSIONS

Decompression and stabilization appear to be key elements of surgical treatment of CSM. In short terms, clinical improvement does not appear to affect patients negatively who show a larger C2-7 SVA after surgery. Optimal C2-7 SVA and necessity for a specific C2-7 correction is unclear. The term "balance" remains a complex entity without clear definition.

Cervical sagittal parameters were closely related to Neck Disability Index score after anterior cervical decompression and fusion

Background

ACDF treatment of CSM is currently recognized as a surgical method with reliable efficacy. However, the cervical radiographic findings in a certain group of patients showed that the symptoms were not completely relieved. This study will investigate the relationship between cervical parameters and prognoses after ACDF surgery.

Methods

This study collected cases of CSM treated with ACDF in Zhongda Hospital from May 2014 to June 2018. The investigators recorded gender, age, cervical sagittal parameters, fusion segment, BMI, symptom duration, and NDI score. To compare the changes of parameters after surgery and explore the correlation between each factor and NDI score.

Results

Generally, cervical lordosis increased and TS-CL decreased after surgery and during follow-up. Postoperative T1S, SVA and SCA decreased significantly compared to preoperative. T1S was positively correlated with CL (r = 0.245), SVA (r = 0.184), and negatively correlated with SCA (r = − 0.314) and NT (r = − 0.222). The last follow-up NDI score was positively correlated with T1S (r = 0.689), SVA (r = 0.155), TS-CL (r = 0.496), and age (r = 0.194), while negatively correlated with SCA (r = − 0.142). A linear regression model was established with the following formula: NDI = 0.809 × (T1S) − 0.152 × (CL) + 1.962 × (Sex) + 0.110 × (Age). T1S (B = 0.205, P < 0.001), CL (B = − 0.094, P = 0.041), and NT (B = 0.142, P = 0.023) were independent risk factors that affected whether the last follow-up NDI score was greater than preoperative.

Conclusions

In ACDF treatment of CSM, there exists a close correlation between cervical sagittal parameters and NDI scores. T1S, CL, sex, and age were linearly dependent on NDI scores. The increase of T1S, NT, and the decrease of CL were risk factors that affected follow-up NDI score greater than preoperative. Reducing T1S is beneficial to clinical recovery.

Radiological outcomes following hyperlordotic cage insertion in anterior cervical discectomy and fusion

BACKGROUND

Cervical alignment is associated with myelopathy and quality of life. Anterior cervical discectomy and fusion (ACDF) aims to decompress neural structures and optimise cervical alignment. This study examines the quantitative impact of the hyperlordotic 15° ACDF cage on cervical alignment, and compares it to that of the standard lordosis cage.

METHODS

A retrospective analysis of radiographical parameters of cervical alignment was conducted in 80 consecutive ACDF patients from two institutions between 2013 and 2017. Forty received 15° cages, 40 received standard cages. Pre- and post-operative Cobb angles and sagittal vertical axes (SVA) were generated from radiographical imaging utilising the Surgimap^TM program. Changes in lordosis and SVA were compared within and between groups, and the significance of the change evaluated using the Student t-test.

RESULTS

In both groups, post-operative device level, segmental, and global Cobb angles were superior to preoperative values (P<0.05), especially among patients with preoperative kyphosis (P<0.05). Trends suggested greater changes in lordosis in the 15° group, but they did not reach statistical significance (P=0.06-0.23). However, subgroup analyses indicated greater device level Cobb angle change in patients less than 65 yo (P=0.049), and those with preoperative lordosis (P=0.003). Neither standard nor hyperlordotic cages significantly improved SVA in this study.

CONCLUSIONS

Hyperlordotic and standard cages both improve cervical lordosis segmentally and globally. Hyperlordotic cages were not shown to be statistically superior to standard cages in this study. Prospective studies featuring consistent imaging modalities are necessary to further delineate their utility.

Doing the Same Thing and Expecting a Different Outcome: It Is Time for a Questioning Philosophy and Theory-Driven Chiropractic Research

OBJECTIVE

The purpose of this commentary is to discuss the philosophical and hypothetical underpinnings of chiropractic and consider whether there is a need for chiropractic to have a questioning philosophy and theory-driven process to guide future scientific endeavors in the profession.

DISCUSSION

The earliest beliefs of the chiropractic founders centered on chiropractic vertebral subluxation but differed on whether this was a static, bone-out-of-place misalignment or a lesion whereby joints had lost their normal direction or range of motion. More recently, new hypotheses such as dyskinesia, inflammation, and neuroplasticity attempt to explain the purported clinical effects of chiropractic. Yet practitioners and students advocate for both traditional viewpoints that typically tout misalignment and embrace a science of chiropractic. I propose that chiropractors should not have to choose between philosophy and science. Instead, they should advocate for adoption of a modern questioning philosophy that not only informs their clinical questions and drives their theories, but also that is in turn influenced by outcomes from their research. Such a questioning philosophy is in stark contrast with the dogma that some have mislabeled as "philosophy" in the profession. I recommend that a review of chiropractic hypotheses and a theory-driven research process is needed to help guide the profession's research agenda given its wide range of clinical activities and limited resources. As the chiropractic profession increasingly embraces evidence-informed practice, enhanced integration within the wider health care community may then result in further gains in utilization.

CONCLUSION

Theory-driven research that results from and subsequently informs a questioning philosophy may expose truths related to practice behaviors, activities, and outcomes, and spur more complete integration of chiropractic within the wider health care community.