Analysis of risk factors of axial neck pain in posterior cervical single-door laminoplasty from the perspective of cervical sagittal plane

Changes in cervical sagittal parameters and the impact on axial symptoms after two types of posterior single-door cervical decompression surgeries

OBJECTIVE

The present study aimed to assess the impact of two posterior single-door cervical decompression procedures on axial symptoms and cervical sagittal parameters in patients with cervical spondylosis.

METHODS

A retrospective study was performed on the clinical records of 185 patients diagnosed with cervical spondylosis who had surgical interventions from January 2021 to January 2023. The patients were categorized into two groups: a study group that underwent laminoplasty combined with C3 laminectomy, and a control group that received the standard C3-7 single-door laminoplasty procedure. The groups were compared based on postoperative Japanese Orthopaedic Association (JOA) scores, incidence of axial symptoms, and cervical parameters such as range of motion (ROM), cervical curvature index (CCI), and C2-7 Cobb angle.

RESULTS

No notable differences were observed in JOA scores and the rates of neurological function recovery between the groups. The occurrence of axial symptoms was markedly reduced in the study group when compared to the control group, with rates of 22.50 % and 61.54 %, respectively.(P < 0.05). Postoperatively, a significant reduction in CCI was observed in both groups (P < 0.05). However, the study group showed a markedly more substantial improvement in CCI than the control group, with the difference reaching statistical significance (P < 0.05). Additionally, the study group showed significantly less loss of ROM and cervical curvature than the control group post-surgery (P < 0.05).

CONCLUSION

Compared to conventional single door laminoplasty, laminoplasty with C3 laminectomy more effectively decompresses nerves in patients with cervical spondylosis while preserving the structural and functional integrity of the cervical spine and minimizing postoperative axial symptoms. This surgical approach is crucial for maintaining cervical sagittal balance and functional integrity.

The new proposal of the relationship between axial pain and hinge fracture and facet involvement after open-door laminoplasty with titanium spacers

STUDY DESIGN

This was a retrospective, observational study.

OBJECTIVES

Postoperative axial pain (AP) is a well-known complication of cervical posterior surgery. It can be caused by various reasons, but the etiology remains unclear. This study aimed to investigate risk factors for postoperative AP after open-door laminoplasty. A previous meta-analysis revealed muscle damage, female, age of <60 years, and longer collar application as possible risk factors for postoperative AP after cervical posterior procedures. However, the postoperative AP etiology, specifically for open-door laminoplasty, has been inconclusive and remains conflicting.

METHODS

This retrospective study included 129 adult patients who underwent open-door cervical laminoplasty for degenerative diseases in our single institution from January 2015 to October 2021. Postoperative AP was defined as intolerable pain on the neck or shoulder that lasted for >1 month postoperatively. We compared the demographic and radiographic characteristics of AP and non-AP groups.

RESULTS

Postoperative AP developed in 62 (48.1%) patients. Intraoperative hinge fracture (HF) and facet involvement by miniscrews were significantly greater in the AP group than in the non-AP group (P < 0.05). Using a logistic regression model, multivariate analysis revealed that HF was significantly associated with postoperative AP (odds ratio = 2.83, 95% confidence interval = 1.28-6.44, P = 0.011).

CONCLUSIONS

HF and facet involvement were risk factors for postoperative AP after open-door laminoplasty with titanium spacers. Careful surgical manipulation is required to prevent postoperative AP.

Axial Symptoms After Conventional and Modified Laminoplasty: A Meta-analysis

PURPOSE

The study aims to evaluate the impact of procedural variations in single-door laminoplasty on axial symptoms (AS) and neurologic outcomes.

METHODS

A comprehensive literature search was conducted across PubMed, EMBASE, and the Cochrane Library, adhering to specific inclusion criteria. We extracted data on the prevalence of AS in both the modified and conventional laminoplasty groups from the selected studies. Neurologic outcomes were assessed using the Japanese Orthopedic Association (JOA) recovery rate, which was subsequently converted to Hedge's g for analysis. Forest plots were generated to visualize the effect sizes, and publication bias was assessed using both funnel plots and Egger's test.

RESULTS

Fourteen studies comprising 1201 patients were included in this meta-analysis focused on AS. The aggregated SMD was -0.891 with a 95% CI of -1.146 to -0.631 (P < 0.01), denoting a statistically significant reduction in AS in the modified laminoplasty group compared with the conventional approach. Of the 14 studies, 10, encompassing 898 patients, contributed data for JOA recovery rate analysis. The overall effect size was 0.089, with a 95% CI ranging from -0.090 to 0.267, and a P value of 0.2901, indicating no significant difference in neurologic outcomes between the 2 techniques. No evidence of publication bias was detected.

CONCLUSIONS

This meta-analysis demonstrates that modified laminoplasty is associated with a significant reduction in the incidence and severity of axial symptoms, without compromising neurologic functionality.

Effect of T1 Slope on Disappearance of Cervical Lordosis after Posterior Cervical Double-Door Laminoplasty Based on Medical Informatics

Cervical sagittal balance plays a pivotal role in spine surgeries as it has a significant impact on the clinical outcomes in cervical spine surgery. Image processing techniques have significantly improved the accuracy and precision of cervical surgical techniques. This study aims to investigate the effects of T1 slope (T1s) on the disappearance of cervical lordosis after posterior cervical double-door laminoplasty using medical informatics and radiographic measures. To do so, we determined and measured the loss of T1s and cervical lordosis during the postoperative follow-up period in patients with double-door posterior cervical laminoplasty. Patients (n = 40) who underwent posterior cervical double-door laminoplasty participated in this study. For all patients, the difference between the preoperative T1s (angle between the upper edge of T1 and the horizontal line) and preoperative and postoperative cervical lordosis (Cobb method) was estimated, and the linear relationship between the two was statistically analyzed to observe the influence of preoperative T1s on postoperative cervical lordosis disappearance. The average preoperative T1s was 23.54°, and the average preoperative cervical lordosis angle was 8.50°. After 1-20 months of follow-up (mean = 9.53 months), the average postoperative cervical lordosis was 8.50°, and the average loss of cervical lordosis was 0.22°. Twenty cases had different degrees of lordosis angle loss after the operation, with an average loss of 9.31°. All patients were divided into groups A and B, according to a mean value of T1s = 23.54°, of which T1S > 23.54° was group A and T1s < 23.54 was group B. Cervical lordosis was quantified by the C2-C7 Cobb angle. The Cobb angle difference of cervical lordosis was measured before and after the operation, and its correlation with preoperative T1s was assessed. The preoperative Cobb angle and cervical curvature changes in the two groups were statistically compared, and the difference between the two groups was statistically significant (p < 0.05). The group with a T1s > 23.54° had greater loss of preoperative Cobb angle and cervical curvature. In group A, the mean preoperative cervical disability index (NDI) was 32.4 ± 3.4, and the mean postoperative NDI score was 16.5 ± 2.1. The mean preoperative VAS scores of neck pain and neck pain were 5.41 ± 1.1 and 5.55 ± 0.3, respectively, and the improvement in neck pain was -0.2%. The mean preoperative NDI in group B was 30.1 ± 2.9, and the mean postoperative NDI score was 11.5 ± 3.1. The mean VAS score for preoperative neck pain was 5.11 ± 1.2, that for postoperative neck pain was 4.18 ± 0.7, and that for neck pain improved by 18%. There was a significant difference between the two groups (p < 0.05). The disappearance of cervical lordosis after posterior cervical double-door laminoplasty is an important cause of postoperative cervical spine pain. The T1s is meaningful for predicting the loss of postoperative curvature in patients undergoing posterior cervical double-door laminoplasty. This is especially true for patients with good preoperative cervical curvature without ankylosis and kyphosis but with a wide T1s.

Quantitatively biomechanical response analysis of posterior musculature reconstruction in cervical single-door laminoplasty

BACKGROUND AND OBJECTIVE

The current trend of laminoplasty is developing toward the goal of muscle preservation and minimum tissue damage. Given this, muscle-preserving techniques in cervical single-door laminoplasty have been modified with protecting the spinous processes at the sites of C2 and/or C7 muscle attachment and reconstruct the posterior musculature in recent years. To date, no study has reported the effect of preserving the posterior musculature during the reconstruction. The purpose of this study is to quantitatively evaluate the biomechanical effect of multiple modified single-door laminoplasty procedures for restoring stability and reducing response level on the cervical spine.

METHODS

Different cervical laminoplasty models were established for evaluating kinematics and response simulations based on a detailed finite element (FE) head-neck active model (HNAM), including ① C3 - C7 laminoplasty (LP_C37), ② C3 - C6 laminoplasty with C7 spinous process preservation (LP_C36), ③ C3 laminectomy hybrid decompression with C4 - C6 laminoplasty (LT_C3 + LP_C46) and ④ C3 - C7 laminoplasty with unilateral musculature preservation (LP_C37 + UMP). The laminoplasty model was validated by the global range of motion (ROM) and percentage changes relative to the intact state. The C2 - T1 ROM, axial muscle tensile force, and stress/strain levels of functional spinal units were compared among the different laminoplasty groups. The obtained effects were further analysed by comparison with a review of clinical data on cervical laminoplasty scenarios.

RESULTS

Analysis of the locations of concentration of muscle load showed that the C2 muscle attachment sustained more tensile loading than the C7 muscle attachment, primarily in flexion-extension (FE) and in lateral bending (LB) and axial rotation (AR), respectively. Simulated results further quantified that LP_C36 primarily produced 10% decreases in LB and AR modes relative to LP_C37. Compared with LP_C36, LT_C3 + LP_C46 resulted in approximately 30% decreases in FE motion; LP C37 + UMP also showed a similar trend. Additionally, when compared to LP_C37, LT_C3 + LP_C46 and LP C37 + UMP reduced the peak stress level at the intervertebral disc by at most 2-fold as well as the peak strain level of the facet joint capsule by 2-3-fold. All these findings were well correlated with the result of clinical studies comparing modified laminoplasty and classic laminoplasty.

CONCLUSIONS

Modified muscle-preserving laminoplasty is superior to classic laminoplasty due to the biomechanical effect of the posterior musculature reconstruction, with a retained postoperative ROM and loading response levels of the functional spinal units. More motion-sparing is beneficial for increasing cervical stability, which probably accelerates the recovery of postoperative neck movement and reduces the risk of the complication for eventual kyphosis and axial pain. Surgeons are encouraged to make every effort to preserve the attachment of the C2 whenever feasible in laminoplasty.