Exceptional Conditions for Favorable Neurological Recovery After Laminoplasty in Cases with Cervical Myelopathy Caused by K-line (-) Ossification of Posterior Longitudinal Ligament

Evaluating the Predictive Value of K-Line Conversion in Surgical Outcomes for K-Line Negative Cervical Ossification of the Posterior Longitudinal Ligament (OPLL): Laminectomy with Fusion versus Laminoplasty

BACKGROUND CONTEXT

Laminectomy with fusion (LF) and laminoplasty are common treatments for K-line negative cervical ossification of the posterior longitudinal ligament (OPLL). However, the clinical significance of postoperative K-line conversion from negative to positive remains unclear.

PURPOSE

To determine whether converting a K-line from negative to positive improves surgical outcomes in patients with cervical OPLL by comparing LF and laminoplasty.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Patients with cervical myelopathy due to K-line negative OPLL who underwent LF or laminoplasty, with ≥1 year of follow-up.

OUTCOME MEASURES

Primary outcomes included neck and arm pain visual analog scale (VAS) scores, neck disability index (NDI), Japanese Orthopedic Association (JOA) score, JOA recovery rate, and radiographic parameters (C2-C7 lordosis, modified K-line interval).

METHODS

We compared radiographic and clinical outcomes between the two groups.

RESULTS

Among 85 patients with K-line-negative OPLL (39 LF, 46 laminoplasty), postoperative K-line conversion occurred significantly more frequently in the LF group (56.4% vs. 16.8%; p <0.001). Although laminoplasty better preserved cervical range of motion and reduced neck pain, LF provided superior neurologic outcomes, as indicated by higher final JOA scores and recovery rates. Patients who achieved K-line conversion had significantly higher rates of favorable clinical outcomes compared to those who did not (58.1% vs. 27.7%; p=0.019). Multivariate regression analyses further demonstrated that K-line conversion independently predicted favorable clinical outcomes (odds ratio [OR]: 3.900; p = 0.023), and LF was significantly associated with a higher likelihood of K-line conversion compared to laminoplasty (OR: 3.683; p = 0.033).

CONCLUSION

In patients with K-line-negative cervical OPLL, postoperative conversion to K-line-positive status is significantly associated with improved neurological outcomes. Although laminoplasty provides advantages regarding neck pain relief and motion preservation, LF more reliably facilitates K-line conversion and suppresses kyphosis, leading to superior clinical outcomes. Careful preoperative evaluation of cervical alignment, combined with surgical strategies aimed at promoting K-line conversion, may optimize surgical results.

LEVEL OF EVIDENCE

III.

Predicting Neck Dysfunction After Open-Door Cervical Laminoplasty - A Prospective Cohort Patient-Reported Outcome Measurement Study

OBJECTIVE

To analyze the predictive factors for neck pain and cervical spine function after laminoplasty for degenerative cervical myelopathy (DCM) using K-means for longitudinal data (KML).

METHODS

In this prospective cohort study, we collected clinical and radiographic data from patients with DCM who underwent cervical laminoplasty. A novel index of surgical outcome, "neck function," which comprises neck pain and cervical spine function according to the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire, was proposed. We treated surgical outcomes as longitudinal rather than cross-sectional data and used KML for analysis. Patients were categorized as having good or poor outcomes based on the KML graph of neck pain and cervical spine function.

RESULTS

From 2016 to 2020, 104 patients underwent laminoplasty for DCM; however, 35 patients were excluded because of loss to follow-up or incomplete data. The authors found that central canal stenosis (odds ratio [OR], 17.93; 95% confidence interval [CI], 1.26-254.73; p=0.03) and preoperative neck pain (OR per 1 point increase=1.49; 95% CI, 1.12-1.99; p=0.006) were 2 negative predictive factors and that a positive K-line during flexion was a positive predictive factor (OR, 0.11; 95% CI, 0.01-0.87; p=0.036) for neck function after laminoplasty.

CONCLUSION

Central canal stenosis, preoperative neck pain and a K-line during flexion were found to be predictive of postoperative neck pain and cervical spine function after laminoplasty. To achieve better surgical outcomes for neck function, the authors suggest the utilization of these determinants as a guiding framework for the selection of surgical approaches for DCM.

A Novel Posterior Compression Score System for Outcome Prediction in Laminoplasty Treated OPLL Patients: A Propensity-Matched Analysis

STUDY DESIGN

A retrospective observational study.

OBJECTIVE

To describe a novel outcome indication system, the posterior compression score (PCS), and investigate its clinical value in cervical ossification of the posterior longitudinal ligament (OPLL) patients treated with laminoplasty.

METHODS

A total of 282 OPLL patients who underwent laminoplasty from January 2013 to December 2018 were reviewed. The patients were divided into high-score (HS) or low-score (LS) groups based on whether the PCS was over 8. Propensity score matching analysis with a caliper of .1 was used to attenuate the potential selection bias. Clinical measurements, including the Japanese Orthopedic Association (JOA) score, visual analog scale (VAS), neck disability index (NDI), and radiological measurements, including C2-C7 lordotic angle and range of motion (ROM), were compared between the groups.

RESULTS

The mean follow-up period was 29.87 ± 9.17 months. There were no significant differences between the two groups regarding patients' baseline demographical and clinical characteristics after propensity score matching. No significant differences were found in the operative time, blood loss, postoperative VAS score for neck and arm pain, postoperative C2-C7 lordotic angle, or postoperative ROM (P > .05). However, the postoperative JOA score and recovery rate were significantly higher in the HS group than in the LS group, while the postoperative NDI was significantly lower in the HS group (P < .05).

CONCLUSION

OPLL patients with higher PCS scores displayed better clinical outcomes. The novel PCS system is suggested to be a reliable scoring system for surgical outcome evaluation in patients with cervical OPLL.

Usefulness of digital tomosynthesis in diagnosing cervical ossification of the posterior longitudinal ligament: a comparative study with other imaging modalities

PURPOSE

The diagnosis and classification of ossification of the posterior longitudinal ligament (OPLL) can be difficult with radiography alone; therefore, computed tomography (CT) is also usually performed. There are many reports on the usefulness of digital tomosynthesis (DTS) for image analysis in orthopedics. This study aimed to compare the accuracy of DTS with radiography and CT for the diagnosis and classification of cervical OPLL (C-OPLL).

MATERIALS AND METHODS

We included 31 patients with OPLL and 30 with cervical spondylotic myelopathy. The patients' cervical spine radiography, DTS, and CT images were each evaluated twice by three specialists and three residents.

RESULTS

In the intra-observer reliability study, there was one observer with a fair level of kappa values for radiography and DTS among three residents. The kappa values for CT were the best for all observers. In the inter-observer reliability study, the interclass correlation coefficient (ICC) values were high for both diagnosis and classification by specialists at the almost perfect level for all three imaging modalities. On the other hand, the ICC values for both diagnosis and classification for radiography by the residents were lower than those for DTS and CT.

CONCLUSIONS

This study revealed that DTS may be an alternative to CT for the diagnosis and classification of C-OPLL by specialists. Caution should be exercised in diagnosing and classifying C-OPLL using radiography and DTS by residents, and the use of CT is recommended.

Risk factors for poor neurological outcomes after unilateral open-door laminoplasty: an analysis of the characteristics of ectopic bone

Background

The factors affecting neurological outcomes with unilateral open-door laminoplasty have been controversial. The purpose of this study was to evaluate the impact of the characteristics of ectopic bone on poor neurological outcomes after unilateral open-door laminoplasty.

Methods

We retrospectively analyzed the clinical data of 112 patients who underwent unilateral open-door laminoplasty from September 2017 to September 2020. According to the Japanese Orthopedic Association score recovery rate after surgery (Japanese Orthopedic Association recovery rate ≥ 50% and < 50%, respectively), all patients were divided into “poor” and “good” groups. The characteristics of ectopic bone and the position relationship between the open side and ectopic bone (for lateral ossification) in the two groups were compared and analyzed. Univariate and multivariate analyses were used to determine the risk factors for poor neurological outcome.

Results

We identified patients with a mean age of 58.39 years and a mean follow-up of 25.43 months. Sixty (53.6%) patients experienced recovery of poor neurological function. On univariable analysis, significant predictors of poor neurological recovery were occupation rate of spinal canal > 60% (p = 0.000), ossification extending to C2 (p = 0.006), lateral ossification (p = 0.032) and opening side on the ipsilateral side of the ectopic bone (p = 0.011). Multivariate logistic regression analysis revealed that the occupation rate of spinal canal > 60% (P = 0.003), ossification extending to C2 (P = 0.041) and opening the door on the ipsilateral side for lateral ossification (P = 0.013) were independent risk factors for poor prognosis of neurological function.

Conclusions

An occupation ratio > 60% is the most important risk factor. Another one is ossification of the posterior longitudinal ligament extending to C2. Meanwhile, opening the door on the ipsilateral side is indeed a risk factor for lateral ossification. Better neurological function may be obtained by choosing the opposite side of the heterotopic bone as the open side. Therefore, the design of the surgical plan should comprehensively consider these factors.