Background:The anchor at C2 often serves as a key stabilizer in cervical spine fusion surgery. Although the pedicle screw is considered the standard fixation method at C2, the laminar screw is also a widely used alternative due to its biomechanical stability, comparable to that of C2 PS. However, malpositioning of C2 LS carries a risk of neural injury and compromised fixation stability, and the use of surgical assistance has been reported to improve placement accuracy. The robotic system is a relatively new technology for PS placement, and its application has recently expanded to the cervical spine. The present study aimed to investigate the accuracy of C2 laminar screw placement with robot assistance. Methods:This prospective study evaluated 11 C2 laminar screws in 11 patients who underwent cervical fusion surgery with the robot assistance between March 2024 and June 2025. Results:All 11 C2 laminar screws were successfully placed with no cortical breaches and no screw-related complications. The mean deviations at both the entry point and at a depth of 20 mm were less than 1.0 mm in both the axial and sagittal planes. Conclusions:The results of this study suggest that the robotic system is a potential tool to facilitate accurate C2 laminar screw placement in clinical settings.

STUDY DESIGN:A retrospective study. OBJECTIVE:To investigate the surgical outcomes of functional balance stability in patients with cervical compressive myelopathy (CCM) using the patient-reported outcome measure (PROM) of the Falls Efficacy Scale-International (FES-I) together with an objective evaluation using the stabilometric test. SUMMARY OF BACKGROUND DATA:Impaired functional balance, including standing and gait instability, is a common symptom in patients with CCM. However, studies evaluating the surgical outcomes of this symptomatology using PROMs are lacking. METHODS:Data of patients who underwent decompressive surgery for CCM were retrospectively reviewed. Functional balance stability was evaluated subjectively using the FES-I instrument and objectively using a stabilometric test. Changes in these measures from baseline to 1 year postoperatively were analyzed. In addition, subgroup analyses were conducted, categorizing patients into the M (baseline FES-I score of 20-27 points) and H groups (baseline FES-I score ≥28 points). RESULTS:A total of 133 patients (mean age: 65.1 y; males: 55.6%) were included in the analysis, with 43 and 90 patients assigned to the M and H groups, respectively. For the entire study population, the FES-I score significantly improved at 1 year postoperatively compared with that at baseline. Subgroup analysis showed that the 1-year postoperative FES score in the H group demonstrated a significant improvement compared with the baseline score; however, the score was still inferior to that of the M group. Regarding objective measures, significant improvements in stabilometric parameters were observed after surgery compared with those at baseline, with changes closely mirroring those of the FES-I score. CONCLUSIONS:Surgery can enhance functional balance stability in the daily activities of patients with CCM. However, patients with impaired functional balance stability before surgery are likely to experience greater residual symptoms postoperatively. Therefore, to minimize postoperative sequelae, early surgical intervention is recommended when the symptoms are still mild. LEVEL OF EVIDENCE:Level 3.

BACKGROUND CONTEXT:Whether the width of laminectomy is a risk factor for the development of C5 palsy (C5P) remains controversial, partly due to confounding variables inherent in retrospective clinical studies. PURPOSE:To investigate the relationship between laminectomy width, posterior shift of the spinal cord, and elongation of the anterior rootlets using an animal model. STUDY DESIGN:Basic in vivo experimental study. METHODS:A total of 18 Sprague-Dawley rats were randomly assigned to 3 groups: Group L (limited laminectomy, N = 6), Group W (wide laminectomy, N = 6), and Group S (sham surgery, N = 6). Animals were evaluated pre- and postoperative days 3, 10, and 14. The widths of the laminectomy, posterior spinal cord shift, and anterior rootlet length were quantified using computed tomography-myelogram images. Motor evoked potentials (MEPs) were recorded from the deltoid (C5-C6 innervated) and triceps brachii (C7-T1 innervated) muscles. RESULTS:Postoperative posterior shift of the cervical cord was observed in both experimental groups. However, Group W showed significantly greater displacement than Group L at the C4-C6 vertebral levels on postoperative days 10 and 14, corresponding to a greater elongation of the C5-C7 anterior rootlets. MEP latency of the deltoid muscle was significantly longer in Group W than in Group L at postoperative days 10 and 14, and significantly longer than in Group S at all postoperative time points. Conversely, no statistically significant differences in MEP latency of the triceps brachii were observed among all groups. CONCLUSIONS:Limited laminectomy may prevent C5P by minimizing elongation of the intradural anterior rootlets caused by gradual posterior shift of the cervical spinal cord. CLINICAL SIGNIFICANCE:This study provides insights for clinicians regarding C5 palsy prevention. By limiting the width of degree of laminectomy, posterior shift of the spinal cord, and thus elongation of the anterior rootlets, can be reduced. These findings support the hypothesis that root tethering from spinal cord shift is a likely mechanism of C5P.

Kyphotic deformity following the loss of cervical lordosis can lead to unfavourable neurological recovery after cervical laminoplasty (CLP); therefore, it is essential to identify its risk factors. Recent studies have demonstrated that the dynamic parameters of the cervical spine, based on baseline flexion/extension radiographs, are highly useful to estimate the loss of cervical lordosis after CLP. However, it remains unclear whether such dynamic parameters can predict kyphotic deformity development after CLP. Hence, the present study aimed to investigate whether the dynamic parameters could predict kyphotic deformity in patients with cervical spondylotic myelopathy (CSM) after CLP. This retrospective study included 165 patients, consisting of 10 and 155 patients with and without cervical kyphosis of C2-C7 angle <= -10 degrees at the final follow-up period, respectively. Among the static and dynamic parameters of the cervical spine, greater cervical kyphosis during flexion (fC2-C7 angle) demonstrated the best discrimination between these two cohorts, with an optimal cutoff value of - 27.5 degrees. Meanwhile, greater gap range of motion (gROM = flexion ROM - extension ROM ) had the highest ability to predict a loss of >= 10 degrees in C2-C7 angle after CLP, with an optimal cutoff value of 28.5 degrees. This study suggests that in patients with CSM, fC2-C7 angle <= -25 degrees on baseline radiographs is a potential risk for kyphotic deformity after CLP. In clinical practice, the patients with this criterion (fC2-C7 angle <= -25 degrees) along with gROM >= 30 degrees are at high risk of developing significant kyphotic deformity after CLP.

CONTEXT:Patients with cervical compressive myelopathy (CCM) often complain of body balance problems, such as fear of falling and bodily unsteadiness. However, no accepted patient-reported outcome measures (PROMs) for this symptomatology exist. The Falls Efficacy Scale-International (FES-I) is one of the most widely used PROMs for evaluating impaired body balance in various clinical fields. OBJECTIVE:To examine reliability, validity, and minimum clinically important difference (MCID) of the FES-I for the evaluation of impaired body balance in patients with CCM. METHODS:Patients who underwent surgery for CCM were retrospectively reviewed. The FES-I was administered preoperatively and at 1 year postoperatively. Further, cJOA-LE score (subscore for lower extremities in the Japanese Orthopaedic Association score for cervical myelopathy) and stabilometric data, obtained at the same time points of the FES-I administration, were analyzed. Reliability was examined through internal consistency with Cronbach's alpha. Convergent validity was studied using correlation analysis. The MCID was estimated using anchor- and distribution-based methods. RESULTS:Overall, 151 patients were included for analysis. Cronbach's alpha coefficient was the acceptable value of 0.97 at both baseline and 1 year postoperatively. As for convergent validity, the FES-I had significant correlations with the cJOA-LE score and stabilometric parameters both at baseline and 1 year postoperatively. The MCID calculated using anchor- and distribution-based methods was 5.5 and 10, respectively. CONCLUSION:FES-I is a reliable and valid PROM to evaluate body balance problems for the CCM population. The established thresholds of MCID can help clinicians recognize the clinical significance of changes in patient status.

Study Design: A retrospective study. Objective: To compare the accuracy of cervical pedicle screw (CPS) placement using a robotic guidance system (RGS) with that of using an image guidance system (IGS; navigation system) through propensity score matching. Background: The RGS may provide accurate CPS placement, which may outperform IGS. However, no study has directly compared the accuracy of CPS placement with the RGS to that with the IGS. Patients and Methods: We retrospectively reviewed the data of patients who had undergone cervical fusion surgery using CPS with the RGS or IGS. To adjust for potential confounders (patient demographic characteristics, disease etiology, and registration material), propensity score matching was performed, creating robotic guidance (RG) and matched image guidance (IG) groups. The accuracy of CPS placement from C2 to C6, where the vertebral artery runs, was evaluated on postoperative computed tomography images according to the Neo classification (grade 0 to grade 3). Furthermore, the intraoperative CPS revisions and related complications were examined. Results: Using propensity score matching, 22 patients were included in the RG and matched groups each, and a total of 95 and 105 CPSs, respectively, were included in the analysis. In both the axial and sagittal planes, the clinically acceptable rate (grades 0 + 1) of CPS placement did not differ between the RG and matched IG groups (97.9% vs 94.3% and 95.8% vs 96.2%, respectively). The incidence of CPS revision was similar between the groups (2.1% vs 2.9%), and no CPS-related complications were documented. Meanwhile, the incidence of lateral breach (grades 1 + 2 + 3) was significantly lower in the RG group than in the matched IG group (1.1% vs 7.7%, P = 0.037). Conclusion: The RGS and IGS can equally aid in accurate and safe CPS placement in clinical settings. Nonetheless, RGS can further reduce the lateral breach, compared with IGS.

OBJECTIVE An increasing number of studies have shown that a robotic guidance system (RGS) can provide accurate cervical pedicle screw (CPS) placement. The accuracy of CPS placement with an RGS has mostly been evaluated according to the magnitude of pedicular cortical violation. However, an RGS assists in pedicle screw (PS) placement by directly indicating the preplanned trajectory in the operative field. Therefore, investigating how accurately the planned trajectory is executed is essential to determine the accuracy of CPS placement using an RGS, in addition to evaluating the clinical accuracy. Hence, this study aimed to evaluate the accuracy of CPS placement using an RGS by comparing the executed trajectory with the planned trajectory. METHODS This prospective study analyzed 174 CPSs placed between C2 and C6 in 39 consecutive patients who underwent cervical fusion surgery using an RGS. The deviation of the executed CPS trajectory from the planned trajectory was measured at the entry point and at a depth of 20 mm in both the axial and sagittal planes on CT images. Additionally, its direction was noted (lateral or medial in the axial plane and cephalad or caudal in the sagittal plane). These measurements were analyzed according to spinal levels (C2 and C3-C6), laterality (right and left sides), and registration material (preoperative and intraoperative CT images). Furthermore, clinical accuracy was assessed using the Neo classification (grades 0-3). RESULTS Overall, the mean (+/- SD) deviations from the planned trajectory at the entry point and at a depth of 20 mm were 0.79 +/- 0.65 mm and 0.86 +/- 0.69 mm in the axial plane and 0.88 +/- 0.81 mm and 0.82 +/- 0.79 mm in the sagittal plane, respectively. When separately examining the deviations according to spinal level, laterality, and registration material, the mean deviations were < 1 mm at any point. Analysis of the deviation direction showed that the CPSs were placed divergently from the planned trajectory in the axial plane. In the sagittal plane, the CPSs were likely to be inserted parallel to the planned trajectory. However, at C2 the CPSs were placed in the caudal direction relative to the planned trajectory. Regarding clinical accuracy, the acceptable rates (grades 0 and 1) were 97.7% and 97.1% in the axial and sagittal planes, respectively, without any CPS-related complications. CONCLUSIONS This study suggests that an RGS can reliably execute planned trajectories, aiding accurate CPS placement in clinical settings.

BACKGROUND CONTEXT:During the radiographic examination, the cranium orientation varies not only individually but also within the same subject, in different imaging sessions. Knowing how changes in the orientation of the cranium influences cervical sagittal alignment during the radiographic examination of the cervical spine can aid clinicians in the accurate evaluation for cervical sagittal alignment in clinical practice. PURPOSE:To radiographically examine the influence of cranium orientation on cervical sagittal alignment during radiographic examination in an asymptomatic cohort. STUDY DESIGN:A prospective radiographic study. PATIENT SAMPLE:Eighty asymptomatic volunteers (mean age, 40.4 years; 50.0% male) were enrolled. OUTCOME MEASURES:Cervical sagittal parameters including the regional slope (C1 slope, C2 slope, C5 slope, C7 slope, and T1 slope), Cobb angle (O-C1 angle, C1-C2 angle, C2-C5 angle, C5-C7 angle, and C7-T1 angle), and cranial/cervical offset (sella turcica tilt [ST tilt] and C2 tilt). METHODS:In all participants, standing lateral radiographs of the cervical spine were taken in 3 forward-gazing positions: anteverted-cranium (AC) position; neutral-cranium (NC) position; and retroverted-cranium (RC) position. Cervical sagittal parameters, including the regional slope, Cobb angle, and cranial/cervical offset, in these 3 positions were statistically compared. RESULTS:The C1 and C2 slopes were anteverted and retroverted in the AC and RC positions, respectively, compared to those in the NC position. The C5 slope, C7 slope, and T1 slope were constant among the 3 positions. In O-C2 and C2-C5, statistically significant differences in the regional Cobb angles were identified among the 3 positions; however, there were no significant differences in the C5-C7 or C7-T1 segments. Cranial and cervical offsets of ST tilt and C2 tilt increased and decreased when the cranium was anteverted and retroverted, respectively. CONCLUSIONS:The current study suggests that the adjustment of the cranium orientation when taking cervical spine radiographs is mainly controlled at the upper cervical spine of the O-C2 segment in an asymptomatic cohort. On radiograph, alignment in the upper cervical segment of O-C2 changes; accordingly, the middle cervical segment of C2-C5 can change during the adjustment of cranium orientation. However, alignment in the lower cervical segment of C5-C7 and the cervicothoracic junction of C7-T1 remains constant. Further, cranial/cervical offset increases and decreases when the cranium is anteverted and retroverted, respectively. Our results can help the accurate evaluation of cervical sagittal alignment on plain radiographs in clinical practice.

Case: A 62-year-old woman who had an unremarkable medical history presented with sudden headache and neck pain. After the presentation, complete quadriplegia and respiratory arrest developed, and the patient was urgently intubated. Magnetic resonance imaging revealed an extensive epidural hematoma (EH), and emergency hematoma evacuation was performed. At the 1-year follow-up visit, the patient had no motor deficits. Conclusion: We reported a case of spontaneous cervical EH presenting with respiratory failure that was successfully treated with surgical management. Literature review has shown that the surgical outcome is very poor; nevertheless, prompt surgical decompression of the spinal cord can minimize neurological sequelae.

Study Design: A retrospective study. Objective: To verify the pathophysiology of dysphagia during the acute postoperative phase of anterior cervical surgery and to identify its predictive features, using ultrasonographic (US) examination for upper esophageal sphincter (UES). Summary of Background Data: There are no clinical studies investigating dysphagia after anterior cervical surgery, using US examination for UES. Materials and Methods: We enrolled patients who underwent anterior cervical spine surgery between August 2018 and March 2022. Dysphagia was evaluated using the Eating Assessment Tool-10 (EAT-10) questionnaires. The US examination was performed preoperatively and 2 weeks postoperatively. Three US parameters for morphologic measurements (outer diameter, inner diameter, and muscle thickness) and 4 for functional measurements (displacement, time to relax, passing duration, and time to contract) were assessed. To verify the pathophysiology of postoperative dysphagia, we examined the change in the ratios of US parameters (=US parameter 2 weeks postoperatively /US parameter at baseline ) and the existence of significant correlations with change in the EAT-10 score (=EAT-10 2 weeks postoperatively −EAT-10 at baseline ). To identify the predictive features, the baseline US parameters were compared between dysphagia (+) and dysphagia (−) groups. Results: A total of 46 patients (mean age, 61.3 y; 78.3% male) were included for analysis. A greater increase of the EAT-10 score after surgery was positively correlated with change ratios of the muscle thickness and time to contract and negatively with change ratio of the inner diameter. The dysphagia (+) group exhibited significantly greater inner diameter and smaller muscle thickness at baseline than the dysphagia (−) group. Conclusion: Dysphagia during the acute postoperative phase of anterior cervical surgery is caused by the physical narrowing of the inner lumen due to muscle thickening of the UES and sphincter contractile dysfunction. In addition, a baseline UES morphology characterized by a greater inner diameter and a thinner muscle layer is predictive of postoperative dysphagia.

Cervical laminoplasty (CLP) is an established procedure; however, postoperative concerns such as axial pain, C5 palsy, restriction of neck motion, and loss of lordotic curvature are commonly noted. Moreover, axial pain after laminoplasty is common. However, the cause of this complication has not been fully elucidated. Several studies have suggested the origins of these complications as cervical muscles, and the preservation of paravertebral muscles and early activation of the range of motion have been recommended. Although these countermeasures improved the rate and severity of axial pain, some unexplained axial pain after CLP persists. Specifically, it is difficult to explain the laterality of the severity of the postoperative axial pain because double-door laminoplasty is a completely symmetrical procedure. This case study suggests that the C4 nerve root may contribute to postoperative axial pain. A 48-year-old woman presented with numbness in her

BACKGROUND CONTEXT Cervical compressive myelopathy (CCM), caused by cervical spondylosis (cervical spondylotic myelopathy [CSM]) or ossification of the posterior longitudinal ligament (OPLL), is a common neurological disorder in the elderly. For moderate/severe CCM, surgical management has been the first-line therapeutic option. Recently, surgical management is also recommended for mild CCM, and a few studies have reported the surgical outcome for this clinical population. Nonetheless, the present knowledge is insufficient to determine the specific surgical outcome of mild CCM. PURPOSE To examine the surgical outcomes of mild CCM while considering the minimum clinically important difference (MCID). STUDY DESIGN Retrospective study. PATIENT SAMPLE Patients who underwent subaxial cervical surgery for CCM caused by CSM and OPLL between 2013 and 2022 were enrolled. OUTCOME MEASURES The Japanese Orthopedic Association score (JOA score) was employed as the clinical outcomes. Based on previous reports, the JOA score threshold to determine mild myelopathic symptoms was set at ≥14.5 points, and the MCID of the JOA score for mild CCM was set at 1 point. METHODS The patients with a JOA score of ≥14.5 points at baseline were stratified into the mild CCM and were examined while considering the MCID. The mild CCM cohort was dichotomized into the improvement group, including the patients with an achieved MCID (JOA score ≥1 point) or with a JOA score of 17 points (full mark) at 1 year postoperatively, and the nonimprovement group, including the others. Demographics, symptomatology, radiographic findings, and surgical procedure were compared between the two groups and studied using the receiver operating characteristic (ROC) curve. RESULTS Of 335 patients with CCM, 43 were stratified into the mild CCM cohort (mean age, 58.5 years; 62.8% male). Among them, 25 (58.1 %) patients were assigned to the improvement group and 18 (41.9 %) were assigned to the nonimprovement group. The improvement group was significantly younger than the nonimprovement group; however, other variables did not significantly differ. ROC curve analysis showed that the optimal cutoff point of the patient's age to discriminate between the improvement and nonimprovement groups was 58 years with an area under the curve of 0.702 (p=.015). CONCLUSIONS In the present study, the majority of patients with mild CCM experienced improvement reaching the MCID of JOA score at 1 year postoperatively. The present study suggests that for younger patients with mild CCM, especially those aged below 58 years, subjective neurological recovery is more likely to be obtained. Meanwhile, the surgery takes on a more prophylactic significance to halt disease progression for older patients. The results of this study can help in the decision-making process for this clinical population.

The use of antibiotics can, in rare cases, induce neuromuscular blockade (NMB), resulting in paralytic symptoms. Although such antibiotic-induced NMB has been described in the anaesthesiology and infectious disease literature, it is an unfamiliar clinical entity in the fields of neurosurgery and spinal surgery. Herein, we report a case of periodic quadriplegia due to NMB induced by perioperative prophylactic antibiotic of cefazolin, resulting in highly confusing paralytic symptoms during the acute postoperative phase of cervical laminoplasty, together with a review of the relevant literature.

Study Design: This was a retrospective study. Objective: The objective of this study was to investigate the diagnostic utility of percutaneous ultrasonography (PUS) for postoperative epidural hematoma (EH) as a postoperative complication. Summary of Background Data: We investigated the usefulness of PUS for determining the need of surgical evacuation of postoperative EH by comparing the postoperative magnetic resonance imaging (MRI) and PUS of the spinal cord. Materials and Methods: This study included patients who underwent cervical laminoplasty using suture anchors. Regular MRI and PUS were performed 1 week postoperatively. Whenever the patients exhibited neurological deterioration, MRI and PUS were performed. The spinal cord decompression status was classified into 3 grades using MRI and PUS. The existence of spinal pulsation was determined by PUS. Results: One hundred thirty-one patients were investigated. The decompression status by MRI and PUS, and the pulsation status by PUS showed a correlation with neurological deterioration (P<0.001). Four cases showed postoperative neurological deterioration and required revision surgery. The decompression status in these cases was classified as “poor” by both MRI and PUS, and as “no-pulsation” by PUS pulsation. The sensitivity and specificity for neurological deterioration was 100% and 95.1% in MRI decompression, 100% and 92.9% in PUS decompression, and 100% and 99.2% in PUS pulsation, respectively. Conclusions: This is the first report that the disappearance of spinal pulsation was associated with neurological deterioration. PUS was useful in determining the need of surgical evacuation for postoperative EH. PUS should be the first choice of examination in the event of postoperative neurological deterioration following a cervical laminoplasty. When the disappearance of pulsation is confirmed, an additional hematoma evacuation surgery should be considered immediately without undertaking MRI. Level of Evidence: Level III.

OBJECTIVE: To investigate whether biologic agents (BAs) reduce a narrow C-2 pedicle screw trajectory, which is often a key stabilizer in surgical treatment, in patients with rheumatoid arthritis (RA). METHODS: A total of 100 patients with RA treated with and without BAs (BA [+] group [n = 50] and BA [-] group [n = 50]), respectively, were included in the present study. Computed tomography (CT) images of their cervical spine, including C-2, were analyzed. The maximum screw diameter at C-2 that could be inserted without breaching the cortex, measured on 3-dimensional images using a CT-based navigation system, was compared between the groups with and without BA administration. Furthermore, the destruction of the atlantoaxial joint was examined using CT images. The risk factors for a narrow C-2 pedicle were elucidated among the patients treated with BAs. RESULTS: The pedicle in the BA (+) group had a significantly larger C-2 maximum screw diameter than the BA (-) group (6.00 mm vs. 5.13 mm, P < 0.001), with less destruction of the atlantoaxial joint. Among the BA (+) group, a longer period until the initial administration of BAs and RA disease duration were associated with a narrow C-2 pedicle. CONCLUSIONS: This study suggests that BAs can maintain the trajectory for C-2 pedicle screws, which acts as a key stabilizer in surgical management for the rheumatoid cervical spine, by halting the destruction of the atlantoaxial joint. Early introduction of BAs can be especially important to prevent the narrowing of the C-2 pedicle.

BACKGROUND/CONTEXT:Kyphotic deformity after cervical laminoplasty (CLP) often leads to unfavorable neurological recovery due to insufficient indirect decompression of the spinal cord. Existing literature has described that segmental cervical instability is a contraindication for CLP because it is a potential risk factor for kyphotic changes after surgery; however, this has never been confirmed in any clinical studies. PURPOSE:To confirm whether segmental cervical instability was an independent risk factor for postoperative kyphotic change and to examine whether segmental cervical instability led to poor neurological outcomes after CLP for cervical spondylotic myelopathy (CSM). STUDY DESIGN/SETTING:A retrospective study PATIENT SAMPLE: Patients who underwent CLP for CSM between January 2013 and January 2021 with a follow-up period of ≥1 year were enrolled. OUTCOME MEASURES:Cervical radiographic measurements including C2-C7 lordosis (C2-7 angle), cervical sagittal vertical axis, C7 slope, flexion range of motion (fROM) and extension ROM (eROM) were assessed using neutral and flexion-extension views. Segmental cervical instability was classified into anterolisthesis (AL) of ≥2 mm displacement, retrolisthesis (RL) of ≥2 mm displacement, and translational instability (TI) of ≥3 mm translational motion. The amount of C2-7 angle loss at the follow-up period compared to the preoperative measurements was defined as cervical lordosis loss (CLL). Neurological outcomes were assessed using the recovery rate of the Japanese Orthopedic Association score (JOA-RR). METHODS:CLL was compared among patients with and without segmental cervical instability. Further, multiple linear regression model for CLL was built for the evaluation with adjustment of the reported risks, including cervical sagittal vertical axis, C7 slope, fROM, eROM, and patient age together with AL, RL, and TI, as independent variables. The JOA-RR was also compared between patients with and without segmental cervical instability. RESULTS:A total of 138 patients (mean age, 68.7 years; 65.9% male) were included in the analysis. AL, RL, and TI were found in 12 (8.7%), 33 (23.9%), and 16 (11.6%) patients, respectively. Comparisons among the groups showed that AL led to greater CLL; however, RL and TI did not. Multiple linear regression analysis revealed that greater CLL is significantly associated with greater fROM and smaller eROM (regression coefficient [β]=0.328, 95% confidence interval: 0.178 to 0.478, p<.001; β=-0.372, 95% confidence interval: -0.591 to -0.153, p=.001, respectively). However, there were no significant statistical associations in the AL, RL, and TI. Whereas, patients with AL tended to exhibit lower JOA-RR than those without AL (37.8% vs. 52.0%, p=.108). CONCLUSIONS:Segmental cervical instability is not the definitive driver for loss of cervical lordosis after CLP in patients with CSM; thus, is not a contraindication in and of itself. However, it is necessary to consider the indications for CLP, according to individual cases of patients with AL on baseline radiograph, which is a sign of poor neurological recovery.