Laminar closure after expansive open-door laminoplasty: fixation methods and cervical alignments impact on the laminar closure and surgical outcomes

Residual Paresthesia After Surgery for Degenerative Cervical Myelopathy: Incidence and Impact on Clinical Outcomes and Satisfaction

STUDY DESIGN

Multicenter, prospective cohort study.

OBJECTIVE

The current study aimed to identify the incidence of residual paresthesias after surgery for degenerative cervical myelopathy (DCM), and to demonstrate the impact of these symptoms on clinical outcomes and patient satisfaction.

SUMMARY OF BACKGROUND DATA

Surgery for DCM aims to improve and/or prevent further deterioration of physical function and quality-of-life (QOL) in the setting of DCM. However, patients are often not satisfied with their treatment for myelopathy when they have severe residual paresthesias, even when physical function and QOL are improved after surgery.

MATERIALS AND METHODS

The authors included 187 patients who underwent laminoplasty for DCM. All patients were divided into two groups based on their visual analog scale score for paresthesia of the upper extremities at one year postoperatively (>40 vs. ≤40 mm). Preoperative factors, changes in clinical scores and radiographic factors, and satisfaction scales at one year postoperatively were compared between groups. The authors used mixed-effect linear and logistic regression modeling to adjust for confounders.

RESULTS

Overall, 86 of 187 patients had severe residual paresthesia at one year postoperatively. Preoperative patient-oriented pain scale scores were significantly associated with postoperative residual paresthesia ( P =0.032). A mixed-effect model demonstrated that patients with severe postoperative residual paresthesia showed significantly smaller improvements in QOL ( P =0.046) and myelopathy ( P =0.037) than patients with no/mild residual paresthesia. Logistic regression analysis identified that residual paresthesia was significantly associated with lower treatment satisfaction, independent of improvements in myelopathy and QOL (adjusted odds ratio: 2.5, P =0.010).

CONCLUSION

In total, 45% of patients with DCM demonstrated severe residual paresthesia at one year postoperatively. These patients showed significantly worse treatment satisfaction, even after accounting for improvements in myelopathy and QOL. As such, in patients who experience higher preoperative pain, multidisciplinary approaches for residual paresthesia, including medications for neuropathic pain, might lead to greater clinical satisfaction.

LEVEL OF EVIDENCE

3.

Plate-only open-door laminoplasty is associated with durable, significantly improved clinical outcomes and a very low reoperation rate for progressive spondylosis or adjacent segment disease: average 8-year follow-up

BACKGROUND CONTEXT

Multilevel cervical myelopathy is a common cause of spinal cord dysfunction in adults. Surgical intervention via laminoplasty can provide satisfactory clinical outcomes by expansive decompression of the spinal cord. Traditional suture or bone graft techniques have been associated with insufficient fixation, leading to premature closure and subsequent neurological deterioration. In contrast, plated laminoplasty has been shown to provide stable fixation to maintain canal enlargement, but longer-term outcomes are lacking.

PURPOSE

To evaluate longer-term clinical outcomes and reoperations associated with plate-only open-door laminoplasty.

STUDY DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

Postoperative patients who underwent plate-only open door laminoplasty with minimum 5-year follow up.

OUTCOME MEASURES

modified Japanese Orthopaedic Association (mJOA) score, Neck Disability Index (NDI), and 12-item Short Form Health Survey (SF-12).

METHODS

All patients at a single academic institution who underwent plate-only open-door cervical laminoplasty from 9/1/2006 to 9/1/2016 were identified to ensure minimum 5 year follow up. Clinical outcomes included the modified Japanese Orthopaedic Association (mJOA) score, the Neck Disability Index (NDI), and the 12-item Short Form Health Survey (SF-12). The occurrence of any repeat operations on the cervical spine was evaluated, as well as its cause. The study team attempted to contact all eligible patients to achieve at least 5 years postoperative follow-up. Pairwise t tests were performed to compare clinical outcomes at preoperative, 6 months, 1-year, and final postoperative follow-up with an α level of 0.05.

RESULTS

A total of 774 met the initial inclusion criteria, of which 157 were included in the study (20.3%). Most common reasons for exclusion included inability to reach after 3 attempts (49.48%), inactive phone numbers (20.28%), and patient declining (3.49%). Included patients had an average age of 60.66±10.63 and an average follow-up time of 8.37±2.57 years (minimum 5 years). mJOA scores (preoperative 11.59±2.16) improved significantly at 6-months (14.57±2.07, p<.001), 1-year (15.19±1.95, p<.001), and final follow-up (14.59±2.63, p<.001). NDI (preoperative 33.89±18.54) improved significantly at 6 months (27.89±19.72, p=.03), 1-year (25.96±19.79, p=.01) and final follow-up (17.88±17.17, p<.001). SF-12 MCS (preoperative 44.73) improved significantly at 6 months (52.01, p=.001), 1-year (51.62, p=.008), and final follow-up (52.32, p<.001). No patient underwent reoperations for plate failure or canal closure with recurrent stenosis. Reoperations for progressive spondylosis during the follow up period were rare and occurred in only three patients for new onset radiculopathy (1.9%) and two patients for myelopathy (1.3%) at an average of 3.2 years postoperative. There were no reoperations performed for adjacent segment disease.

CONCLUSIONS

At a minimum of 5 years and an average of more than 8 years postoperative, laminoplasty was associated with significant and sustained improvements in mJOA, NDI, and SF-12 MCS. Importantly, no patients underwent revision surgery for plate failure or recurrent canal closure. Reoperations for new onset radiculopathy and myelopathy were also very rare over the 8-year average follow-up period, with no reoperations for adjacent segment disease. Plate-only laminoplasty is a durable means of treating multilevel myelopathy with excellent longer-term outcomes and a very low risk of reoperation, either for premature closure or the inevitable spondylotic changes that occur over time in patients with similar baseline characteristics to the study population.

Degeneration of Cervical Multifidus Muscles Negatively Affects Physical Activity-related Quality of Life After Laminoplasty for Degenerative Cervical Myelopathy

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The study aimed to investigate the related factors affecting physical activity-related quality of life (QOL) after 2 years of cervical laminoplasty for degenerative cervical myelopathy (DCM), focusing on the degree of preoperative degeneration of the cervical multifidus muscles.

SUMMARY OF BACKGROUND DATA

The association between paraspinal muscle degeneration and clinical outcomes after spinal surgery is being investigated. The effect of preoperative degeneration of the cervical multifidus muscles in patients undergoing cervical laminoplasty is ambiguous.

METHODS

Patients who underwent laminoplasty for DCM and followed up for more than 2 years were reviewed. To evaluate physical QOL, the physical component summary (PCS) of the 36-Item Short-Form Health Survey (SF-36) was recorded at 2 years postoperatively. The degree of preoperative degeneration in the multifidus muscles at the C4 and C7 levels on axial T2-weighted magnetic resonance imaging (MRI) was categorized according to the Goutallier grading system. The correlation between 2-year postoperative PCS and each preoperative clinical outcome, radiographic parameter, and MRI finding, including Goutallier classification, was analyzed. Variables with a P value <0.10 in univariate analysis were included in multiple linear regression analysis.

RESULTS

In total, 106 consecutive patients were included. The 2-year postoperative PCS demonstrated significant correlation with age (R=-0.358, P=0.002), preoperative JOA score (R=0.286, P=0.021), preoperative PCS (R=0.603, P<0.001), C2-C7 lordotic angle (R=-0.284, P=0.017), stenosis severity (R=-0.271, P=0.019), and Goutallier classification at the C7 level (R=-0.268, P=0.021). In multiple linear regression analysis, sex (β=-0.334, P=0.002), age (β=-0.299, P=0.013), preoperative PCS (β=0.356, P=0.009), and Goutallier classification at the C7 level (β=-0.280, P=0.018) were significantly related to 2-year postoperative PCS.

CONCLUSIONS

Increased degeneration of the multifidus muscle at the C7 level negatively affected physical activity-related QOL postoperatively. These results may guide spine surgeons in predicting physical activity-related QOL in patients with DCM after laminoplasty.

LEVEL OF EVIDENCE

Level III.

Cases requiring reoperation for recurrence of myelopathy by lamina closure after a double-door laminoplasty using a modified Kirita-Miyazaki suture method

Background

Progression of kyphosis after laminoplasty sometimes results in the recurrence of myelopathy with lamina closure. However, only a few case reports have been published on the reoperation of double-door laminoplasty using the suture method. This study investigated the incidence and clinical features of reoperation cases caused by the recurrence of myelopathy with lamina closure after double-door laminoplasty using a modified Kirita-Miyazaki suture method.

Methods

A total of 169 patients who underwent double-door laminoplasty were included in this study, with a mean follow-up duration of 6.6 years (range: 2-16). All surgeries were double-door laminoplasties in which the open lamina was sutured to the paravertebral muscle. The reoperation rate for myelopathy recurrence due to lamina closure and the associated risk factors were investigated. The risk factors included age, history, cervical alignment, C2-7 lordosis, the cervical sagittal vertical axis, and C7 slope.

Results

The reoperation rate for recurrence of myelopathy by lamina closure was 3.0% (5/169). All patients showed kyphosis progression after surgery; the spinal cord was more compressed by closed lamina than before the initial surgery. The reoperation group had more patients with neuromuscular or psychiatric disorders (60% [3/5] vs. 2% [4/164]; p < 0.001), kyphotic alignments (60% [3/5] vs. 10% [16/164]; p < 0.001), and cases with less than -10° of C2-7 lordosis (60% [3/5] vs. 7% [11/164]; p < 0.001).

Conclusions

Double-door laminoplasty with the suture method may not be suitable for patients with a neuromuscular or psychiatric disease or those with preoperative C2-7 lordosis less than -10°.

Change in Physical and Mental Quality-of-Life between the Short- and Mid-Term Periods after Cervical Laminoplasty for Cervical Spondylotic Myelopathy: A Retrospective Cohort Study with Minimum 5 Years Follow-up

The mid-term surgical outcomes of cervical spondylotic myelopathy (CSM), evaluated using the cervical Japanese Orthopedic Association (cJOA) score, are reported to be satisfactory. However, there remains room for improvement in quality-of-life (QOL), especially after short-term follow-up. We aimed to demonstrate changes in mental and physical QOL between short- and mid-term follow-ups and determine the predictive factors for deterioration of QOL. In this retrospective cohort study, 80 consecutive patients underwent laminoplasty for CSM. The outcome measures were Short Form-36 Physical Component Summary (PCS), Mental Component Summary (MCS), and cJOA scores. PCS and MCS scores were compared at the 2- and 5-year postoperative time points. Additionally, a multivariate logistic regression model was used to identify the predictive factors for deterioration. Significant factors in the logistic regression analysis were analyzed using receiver-operating characteristic curves. The results showed that MCS scores did not deteriorate after 2 years postoperatively (p = 0.912). Meanwhile, PCS significantly declined between 2 and 5 years postoperatively (p = 0.008). cJOA scores at 2 years postoperatively were significantly associated with PCS deterioration at 2-year follow-up. In conclusion, only physical QOL might show deterioration after short-term follow-up. Such deterioration is likely in patients with a cJOA score <13.0 at 2 years postoperatively.

Comparative Effectiveness and Safety of Open-Door Laminoplasty, French-Door Laminoplasty, Laminectomy and Fusion, and Laminectomy Alone for Multilevel Degenerative Cervical Myelopathy: A Bayesian Network Analysis

OBJECTIVES

To evaluate the comparative effectiveness and safety of open-door laminoplasty (OLP), French-door laminoplasty (FLP), laminectomy and fusion (LF), and laminectomy alone (LA) in treating multilevel degenerative cervical myelopathy (MDCM).

METHODS

Embase, PubMed, and Cochrane library were searched from their inception date to 7 January 2021. Randomized controlled trials and cohort studies comparing OLP, FLP, LF, and LA were identified to perform a network meta-analysis (NMA).

RESULTS

A total of 30 studies with 2671 patients were included. Our NMA results showed no significant difference between LF and OLP, but both are superior to LA and FLP in the comparison of JOA (Japanese Orthopaedic Association) score improvement. LF showed a most unsatisfactory outcome in postoperative range of motion (ROM) compared with LA or OLP or with FLP. For the complication outcome, no significant differences were found. The surface under the cumulative ranking curves (SUCRA) for JOA improvement was as follows: LF, OPL, LA, and FLP. For ROM reduction it was LA, OPL, FPL, and LF. For complications it was LF, LA, OLP, and FLP.

CONCLUSIONS

Considering all the evaluated criteria, none of the procedures showed the best outcome with least complications and optimal efficacy. However, OLP can be most recommended because of its second-ranking spectra in both of JOA improvement and ROM reduction, also with an acceptable incidence of complications, with the third least.

Open-door laminoplasty with stand-alone autologous bone spacers: evaluation of enlarged laminar arch with CT-multiplanar reconstruction

OBJECTIVE

The authors aimed to determine the efficacy of open-door laminoplasty with stand-alone autologous bone spacer for preserving enlarged lamina in patients with cervical myelopathy.

METHODS

Patients who underwent open-door laminoplasty for cervical myelopathy with stand-alone autologous bone spacer and underwent CT 1 week and 1 year after surgery were included in this study. There were 20 men and 13 women, with an average (range) age of 65.0 (37-86) years. Seventeen patients were younger than 70 years, and 16 patients were older than 70 years. Autogenous bone spacers made from spinous processes were used in all patients. Slits were made on both sides of the spacers. The lamina was raised with a curette, and a spacer was inserted without any sutures. Before surgery and 1 week and 1 year after surgery, the anteroposterior diameter (APD) of the spinal canal was measured using midsagittal-plane CT-multiplanar reconstruction. The bone union rate of the hinge side and autogenous bone spacer of each lamina was determined using CT images obtained 1 year after surgery. Results 1 year after surgery were evaluated using Japanese Orthopaedic Association (JOA) score.

RESULTS

The mean ± SD APD increase rate was 56.3% ± 21.3% 1 week after surgery and 51.7% ± 20.6% 1 year later. The average APD decrease rate was 2.9% ± 3.8%. The bone union rate on the hinge side was 100%, and that of autologous bone spacer was 93.8% 1 year after surgery. The mean APD decrease rate was 3.3% in patients younger than 70 years and 2.3% in those older than 70 years. There was no significant difference between the two groups (p > 0.05, nonpaired t-test). The JOA score averaged 10.1 before surgery and 13.3 a year after surgery (total score 17). The average improvement rate was 46.3% ± 26.4%.

CONCLUSIONS

The authors devised and implemented a technique for inserting an autologous bone spacer between the opened lamina and lateral mass without sutures. The enlarged spinal canal was maintained 1 year after surgery. This simple method does not require any instrumentation or additional cost to stabilize the opened lamina.

Laminar Closure in Double-door Laminoplasty for Cervical Spondylotic Myelopathy with Nonkyphotic Alignment

STUDY DESIGN

A retrospective case series.

OBJECTIVE

The aim of this study was to investigate the incidence and clinical features of laminar closure in patients with cervical spondylotic myelopathy (CSM) based on prospectively collected data.

SUMMARY OF BACKGROUND DATA

Laminar closure after single open-door laminoplasty (LAMP) has been reported to result in poor clinical outcomes. However, no studies to date have examined the underlying mechanisms and frequency of laminar closure after double-door LAMP.

METHODS

This study prospectively enrolled 128 consecutive patients with CSM scheduled for double-door LAMP without a laminar spacer at our hospital between 2008 and 2013. Sagittal parameters including C2-7 angle, T1 slope, and cervical sagittal vertical axis (C-SVA), which is defined as the distance between the anterior margin of the external auditory canal plumb line and the posterior-cranial corner of the C7 vertebral body on x-ray, were calculated before and after the operation. Laminar angle was also measured on magnetic resonance images preoperatively and at 1 week and 1 year postoperatively. Laminar closure was defined as > 20% decrease in laminar angle at 1 year compared with that at 1 week postoperatively. The Japanese Orthopedic Association score for cervical myelopathy and the recovery rate determined from the preoperative and postoperative scores were evaluated as clinical outcomes.

RESULTS

In total, 110 patients were completely followed up for at least 1 year (follow-up rate: 85.9%). Laminar closure was observed in six cases (5.5%) at the 1-year follow-up. The recovery rate in these six cases was significantly lower than in cases without laminar closure (16.6% vs. 45.1%, respectively). Logistic regression analysis revealed age and C-SVA as significant risk factors for postoperative laminar closure.

CONCLUSION

This study is the first to investigate the incidence of laminar closure after double-door LAMP without a laminar spacer. Laminar closure occurred exclusively in elderly patients with kyphotic deformity after LAMP.Level of Evidence: 4.

Time Course of Physical and Mental Well-being Improvements After Cervical Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To elucidate the postoperative time course of improvements in physical and mental well-being in patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Spinal surgeons should understand the postoperative course in detail. However, data are still needed regarding the time course of improvements in well-being, a fundamental aspect of human life, after cervical surgery for CSM.

METHODS

One hundred consecutive patients who underwent laminoplasty for CSM, with complete clinical data preoperatively and 3 months and 2 years postoperatively, were enrolled. The Short Form-36 physical component summary (PCS) and mental component summary (MCS) scores were used as parameters of physical and mental well-being, respectively, and 4.0 was defined as the minimal clinically important difference (MCID) for both parameters.

RESULTS

On average, PCS and MCS scores were significantly improved after surgery (P < 0.001, P=0.004, respectively). Moreover, 64 and 48 patients achieved meaningful improvement (>MCID) in PCS and MCS scores at 3 months postoperatively, with maintained improvement (to 2 yr) in 46/64 (71.9%) and 34/48 patients (70.8%), respectively (PCS vs. MCS: P = 0.912). Additionally, 15 of 36 patients (41.7%) and 8 of 52 patients (15.4%) achieved late improvement (meaningful improvement at 2 yr but not at 3 months) in PCS and MCS scores, respectively (PCS vs. MCS: P = 0.007). In multivariate regression analysis, improvement in cJOA score was significantly associated with PCS improvement, but not MCS improvement, at both 3 months and 2 years (P = 0.001, P > 0.001, respectively).

CONCLUSION

The overall outcome of physical well-being improvement is decided within 3 months postoperatively, in proportion to the recovery in myelopathy, with a relatively high chance of meaningful improvement over the next 21 months. The outcome of improvement in mental well-being is decided within 3 months postoperatively, independently from the recovery in myelopathy, with a low chance of meaningful improvement over the next 21 months.Level of Evidence: 3.

The impact of plating level on the postoperative loss of cervical lordosis in alternative skipped-level plating laminoplasty

PURPOSE

The aim of this study is to evaluate the impact of plating level on the loss of cervical lordosis (LCL) after laminoplasty with skipped-level plating.

METHODS

This retrospective study included patients who underwent alternative skipped-level plating laminoplasty from C3 to C6. Patients were divided into two groups according to the plating level. Group 1 had miniplate fixed at C3 and C5 (C3/C5 group), while patients in group 2 were fixed at C4 and C6 (C4/C6 group). The outcome of interest was the difference of LCL between the two groups; meanwhile, kyphosis development after laminoplasty was also compared.

RESULTS

A total of 70 patients were included in our study with a mean age of 60.44 ± 9.97 years. The median follow-up was 15 (12, 16) months. Median lordosis was 15.43° (9.35°, 22.23°) before surgery and 9.88° (4.15°, 18.94°) after, with a median LCL of 4.48° (-0.66°, 8.11°). There were 17 patients in the C3/C5 group, whereas 53 patients in the C4/C6 group. While preoperative C2-C7 Cobb's angle was comparable between the two groups (15.32° (9.73°, 23.84°) vs. 15.51° (9.03°, 21.70°), p = 0.864), there were statistical differences regarding postoperative C2-C7 Cobb's angle (6.54° (2.49°, 16.42°) vs. 10.62° (5.89°, 18.85°), p = 0.006) and LCL (4.74° (4.17°, 12.03°) vs. 4.07° (-1.89°, 6.69°), p = 0.034) between the C3/C5 group and the C4/C6 group. In all, 94.1% (16 of 17) of patients showed some degree of LCL after laminoplasty in the C3/C5 group, which was significantly higher when compared with 64.2% (34 of 52) of C4/C6 group (p = 0.038). Before surgery, there were no kyphosis patients in either the C3/C5 group or the C4/C6 group. Postoperatively, four patients (23.5%) developed kyphotic alignment in the C3/C5 group, but only one (1.9%) in the C4/C6 group (p = 0.013).

CONCLUSIONS

Cervical alignment was compromised after laminoplasty. When alternative skipped-level plating is adopted in laminoplasty from C3 to C6, plating at C4/C6 may better preserve cervical lordosis than plating at C3/C5 after surgery.

Residual numbness of the upper extremity after cervical surgery in patients with cervical spondylotic myelopathy

OBJECTIVE

Although numbness is one of the chief complaints of patients with cervical spondylotic myelopathy (CSM), preoperative factors relating to residual numbness of the upper extremity (UE) and impact of the outcomes on cervical surgery are not well established. The authors hypothesized that severe preoperative UE numbness could be a risk factor for residual UE numbness after surgery and that the residual UE numbness could have a negative impact on postoperative outcomes. Therefore, this study aimed to identify the preoperative factors that are predictive of residual UE numbness after cervical surgery and demonstrate the effects of residual UE numbness on clinical scores and radiographic parameters.

METHODS

The study design was a retrospective cohort study. The authors analyzed data of 103 patients who underwent cervical laminoplasty from January 2012 to December 2014 and were followed up for more than 2 years postoperatively. The patients were divided into two groups: the severe residual-numbness group (postoperative visual analog scale [VAS] score for UE numbness > 40 mm) and the no/mild residual-numbness group (VAS score ≤ 40 mm). The outcome measures were VAS score, Japanese Orthopaedic Association scores for cervical myelopathy, physical and mental component summaries of the 36-Item Short-Form Health Survey (SF-36), radiographic film parameters (C2-7 sagittal vertical axis, range of motion, C2-7 lordotic angle, and C7 slope), and MRI findings (severity of cervical canal stenosis, snake-eye appearance, severity of foraminal stenosis). Following univariate analysis, which compared the preoperative factors between groups, the variables with p values < 0.1 were included in the multivariate linear regression analysis. Additionally, the changes in clinical scores and radiographic parameters after 2 years of surgery were compared using a mixed-effects model.

RESULTS

Among 103 patients, 42 (40.8%) had residual UE numbness. In the multivariate analysis, sex and preoperative UE pain were found to be independent variables correlating with residual UE numbness (p = 0.017 and 0.046, respectively). The severity of preoperative UE numbness did not relate to the residual UE numbness (p = 0.153). The improvement in neck pain VAS score and physical component summary of the SF-36 was significantly low in the severe residual-numbness group (p < 0.001 and 0.040, respectively).

CONCLUSIONS

Forty-one percent of the CSM patients experienced residual UE numbness for at least 2 years after cervical posterior decompression surgery. Female sex and preoperative severe UE pain were the predictive factors for residual UE numbness. The patients with residual UE numbness showed less improvement of neck pain and lower physical status compared to the patients without numbness.

Effect of Titanium Miniplate Fixation on Hinge Fracture and Hinge Fracture Displacement Following Cervical Open-Door Laminoplasty

BACKGROUND

Cervical spondylotic myelopathy is a neuromotor disorder responsible for functional limitations and decreased daily activities. Expansive open-door laminoplasty is the widely accepted procedure for the treatment of multilevel cervical spondylotic myelopathy. Among the various fixation procedures to secure the open lamina, miniplate fixation provides better clinical and radiological outcomes. However, the immediate effects on hinge fracture and hinge fracture displacement following miniplate fixation have not been proven until now. The purpose of our study was to elucidate the impact of cervical open-door angle on the status of spinal cord expansion and hinge fracture, hinge fracture displacement, and the role of implants used during surgery.

METHODS

For this retrospective study, 122 patients who had undergone surgery from September 2016 to November 2017 with preoperative and postoperative radiographs were enrolled. Clinical and radiological outcomes were assessed before and after surgery.

RESULTS

There were no significant differences in demographics, surgery time, blood loss, medical comorbidities, or perioperative and postoperative complications between 2 groups. The recovery rate and Nurick score before and at the follow-up show no statistical significance between the 2 groups, P value > .05 (P = .672) and P > .05 (P = .553), respectively. The statistical analysis shows that the mean hinge fracture in the miniplate group with a cervical open angle >30° was 2.42 ± 1.68 and with a <30° open angle, 0.05 ± 0.23; whereas, in the anchor group the mean hinge fracture in >30° cervical open angle was 2.227 ± 2.50 and in <30° was 0.409 ± 0.503. The results revealed statistical significance between 2 implant groups, P = .024 in the aspect of hinge fracture displacement and implant used.

CONCLUSION

Laminoplasty by titanium miniplate fixation holds the laminae securely, prevents hinge fracture displacement, and promotes spinal cord expansion better than suture anchor fixation.

The Severity of Cervical Disc Degeneration Does Not Impact 2-year Postoperative Outcomes in Patients With Cervical Spondylotic Myelopathy Who Underwent Laminoplasty

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to evaluate the impact of cervical disc degeneration (CDD) severity on 2-year postoperative outcomes following laminoplasty.

SUMMARY OF BACKGROUND DATA

The impact of CDD on postoperative outcomes of cervical laminoplasty has not been well established.

METHODS

A total of 144 patients who underwent open-door laminoplasty for cervical spondylotic myelopathy (CSM) were enrolled. Six cervical discs were independently analyzed for degeneration severity using a previously reported grading system (grade 0: none, grade 3: severest). The relationship between the segmental range of motion (ROM) and the severity of CDD was evaluated. Subsequently, after dividing overall patients into mild and severe CDD groups by the average of CDD scores, the mixed-effect model was applied to assess 2-year postoperative outcomes, including physician-assessed myelopathy scores, patient-reported outcomes, and preoperative radiographic parameters. Finally, as additional analysis, the severe CDD group was further divided into two groups: group 1 included patients with a grade 3 CDD change in their most stenotic level and group 2 included the others. The 2-year postoperative myelopathy score was compared between groups 1 and 2.

RESULTS

The cervical segments with grade 3 CDD showed significantly smaller ROM compared with those with grade 0, 1, or 2 CDD (P < 0.01). There were no significant differences in postoperative improvements in myelopathy, pain, patient-reported physical and mental status, and radiographic parameters, except for quality of life (QOL) scores between CDD groups. A significant (P = 0.02) postoperative improvement in QOL scores was noted in the severe CDD group. In an additional analysis, myelopathy score at 2 years postoperatively was significantly higher in group 1 than group 2 (P = 0.041).

CONCLUSION

The severity of CDD did not negatively impact 2-year postoperative laminoplasty outcomes. The postulated reason is that the decreased segmental instability in the level with severe CDD may affect surgical outcomes positively.

LEVEL OF EVIDENCE

3.

Factors associated with postoperative axial symptom after expansive open-door laminoplasty: retrospective study using multivariable analysis

PURPOSE

The aim of the present study was to investigate the factors associated with axial symptom using multivariable analysis.

METHODS

The authors retrospectively assessed 249 patients treated by open-door laminoplasty. The patients were classified into two groups: axial symptom and no axial symptom group. The possible factors included demographic variables (age, sex, BMI, smoking, heart disease, diabetes, preoperative neck pain, preoperative JOA scores, preoperative NDI, course of disease and pathogenesis) and surgical and radiological variables [operation time, intraoperative blood loss, collar wear time, preoperative cervical curvature, postoperative cervical curvature, T1 slope, preoperative and postoperative C2 sagittal vertical axis (C2 SVA)].

RESULTS

The prevalence of axial symptom was 34.9% (89/249). The collar wear time, preoperative and postoperative C2 SVA were risk factors for axial symptom. A cutoff value of 22.6 mm for preoperative C2 SVA and 3.5 weeks for collar wear time predicted the development of axial symptom.

CONCLUSIONS

The longer collar wear time, larger preoperative and postoperative C2 SVA were positively correlated with the higher incidence of axial symptom.

Preservation of Deep Cervical Extensor Muscle Volume: Comparison Between Conventional Open-Door and Muscle Preserving Laminoplasty Approaches in the Same Patients

BACKGROUND

Surgical laminoplasty techniques have been developed to reduce cervical kyphosis and postoperative axial neck pain and preserve the posterior cervical extensor muscles. We compared a unilateral conventional open approach (OA) and a contralateral muscle preserving approach (MPA) for laminoplasty in the same patients to determine differences in the preservation of the posterior cervical muscles after the 2 approaches.

METHODS

This study was a prospective observational study involving 44 patients who underwent laminoplasty with unilateral OA and contralateral MPA for cervical myelopathy from January 2005 to December 2013. The cross-sectional area (CSA) changes in the posterior cervical extensor muscles (multifidus, semispinalis cervicis, and semispinalis capitis muscles) were measured on computed tomography scan, both pre- and postoperatively.

RESULTS

Using an OA, the multifidus and semispinalis cervicis muscle preservation was 58.2% and 67.0%, but using an MPA, muscle preservation was 97% and 90.8% (P < 0.001 and P = 0.042), respectively. However, the CSA of the semispinalis capitis muscle did not differ significantly between the 2 groups. In terms of the level, conservation of the multifidus muscle was significantly different according to the approach at all levels, and the conservation of the deep extensor muscles was significantly different at the C3-4 level.

CONCLUSIONS

MPA was effective in preserving the volume of deep cervical extensor muscles and helping minimize postoperative musculoskeletal complications. In addition, muscle preservation was more effective at the C3-4 level.

Improvement in Patient Mental Well-being After Surgery for Cervical Spondylotic Myelopathy

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to investigate changes in mental well-being after surgery for cervical spondylotic myelopathy (CSM) and identify factors associated with improvement.

SUMMARY OF BACKGROUND DATA

Posterior cervical surgery with laminoplasty significantly improves myelopathy and physical function in patients with CSM. However, its impact on mental well-being is unclear.

METHODS

Patients who underwent laminoplasty for CSM and had >2 years of follow-up were reviewed (n = 111). The mental component summary (MCS) score was used as a measure of mental well-being. The trend in MCS score change was evaluated using the Jonckheere-Terpstra trend test. Preoperative clinical scores were compared between patients with improvements greater and less than the minimal clinically important difference (MCID). Significant variables were included in a multinomial logistic regression analysis and further validated in a receiver-operating characteristic (ROC) curve analysis. Additionally, the results were confirmed in a long-term observation cohort of patients followed up for >5 years (n = 46).

RESULTS

The improvement in the average MCS score (5.6) was greater than the MCID (4.0). The trend of improvement was sustained for 2 years (P = 0.002), but not for 5 years (P = 0.130). In terms of individual cases, 56 patients (50.5%) achieved MCS score improvement greater than the MCID. These patients showed significantly lower preoperative MCS scores than those without meaningful improvement (P < 0.001). The preoperative "social functioning (SF)" score was independently associated with MCS score improvement (P = 0.001). ROC curve analysis validated the ability of preoperative SF to predict MCS score improvement at 2 and 5 years postoperatively (area under the curve: 0.744, 0.893, respectively).

CONCLUSION

Half of the patients achieved meaningful improvement in mental well-being. A lower preoperative SF score was independently associated with improvement. These results may help identify patients who could experience an improvement in mental well-being after surgery and develop novel approaches to achieve further improvement.

LEVEL OF EVIDENCE

3.

Clinical Impact of Cervical Imbalance on Surgical Outcomes of Laminoplasty: A Propensity Score-Matching Analysis

STUDY DESIGN

This is a retrospective cohort study.

OBJECTIVE

The objective of this study was to identify the impact of preoperative cervical sagittal balance on the 2-year surgical outcomes of laminoplasty.

SUMMARY OF BACKGROUND DATA

The cervical imbalance is considered associated with poor health-related quality of life and poor outcomes for cervical deformity surgery. However, the influences of cervical imbalance on the clinical outcomes of laminoplasty for cervical spondylotic myelopathy (CSM) patients are unclear.

MATERIALS AND METHODS

A total of 277 consecutive CSM patients who underwent laminoplasty were analyzed. From the last consecutive 136 patients, matched control group [cervical sagittal vertical axis (cSVA)<40 mm, n=30] and matched imbalance group (≥40 mm, n=30) were selected based on their propensity score adjusted for age, sex, cervical alignment, and preoperative Japanese Orthopaedic Association (JOA) score. Change in clinical outcomes and radiographic parameters at 2 years postoperatively were compared between the 2 matched groups using mixed-effects model. For the validation of the primary results, factors that correlated with the recovery rate of JOA score of another 141 patients were analyzed using multiple linear regression analysis.

RESULTS

There was no significant interaction between the 2 matched groups in all clinical outcomes, including the severity of myelopathy, patient-oriented health-related quality of life score, physical and mental status, physical functions, and pain score. Regarding the radiographic evaluation, change in cSVA showed significant differences (P=0.038); cSVA was kept stable in the matched control group, whereas its value significantly decreased in the matched imbalance group. Multiple linear regression models demonstrated that preoperative cSVA is not significantly related to the recovery rate of JOA score at 2 years postoperatively (P=0.114).

CONCLUSIONS

Preoperative cervical imbalance did not significantly affect the 2-year surgical outcomes of laminoplasty. Furthermore, cervical imbalance improved after surgery. These results can suggest physicians consider laminoplasty as a treatment for CSM patients regardless of their cervical balance.

LEVEL OF EVIDENCE

Level III-treatment benefits: nonrandomized controlled cohort/follow-up study.

Comparison of the operative time for open door laminoplasty using titanium plate spacers or hydroxyapatite block spacers: a retrospective study

Abstract

Background

Titanium plate (TP) and hydroxyapatite (HA) spacers are widely used during open-door laminoplasty, performed with the patient in a prone position. Reducing operative time is an important consideration, particularly to reduce the risk of postoperative complications in older patients. The purpose of this retrospective cohort study was to compare the operative time for open-door laminoplasty using TP or HA spacers.

Methods

Consecutive patients with a spinal cord injury, without bone injury, and ≥ 50 years of age were included. Multivariate regression analysis was used to compare the operative time between patients in the TP and HA group, adjusting for known factors that can influence surgical and postoperative outcomes. Propensity score matching was used to confirm the robustness of the primary outcome. The cumulative incidence of postoperative complications over 1-year after surgery was also compared.

Results

Of the 164 patients forming our study group, TP spacers were used in 62 and HA in 102. Operative time was significantly shorter for the TP (128 min) than HA (158 min) group (p < 0.001). Both multivariate and propensity score matching analyses confirmed a significant reduction in operative time for the TP, compared to HA, group (regression coefficient, − 30 min and − 38 min, p < 0.001 and p < 0.001, respectively). There was no significant difference in the cumulative incidence of postoperative complications.

Conclusions

The use of TP spacers reduced the operative time for cervical open-door laminoplasty by about 30 min, compared to the use of HA spacers, with no difference in the rate of postoperative complications.

Motion Preservation at All Costs? Multilevel Hinge Nonunion, Plate Breakage, and Intradural Plate Migration After Cervical Laminoplasty: A Case Report and Literature Review

BACKGROUND

Cervical laminoplasty is a motion-preserving procedure that addresses spinal cord compression and avoids postlaminectomy kyphosis associated with cervical laminectomy. The most common complications include C5 nerve palsy, axial neck pain, hinge nonunion, and premature closure. Plating is a relatively newer method of laminoplasty fixation that may provide greater stabilization postoperatively and reduce the risk of laminoplasty closure compared with less rigid (e.g., suture) fixation techniques. Although prior studies have reported low rates of laminar/lateral mass screw back out, plate breakage and migration have not been previously described in the literature. The purpose of this paper is to present a case of multilevel hinge nonunion, plate breakage, and plate fragment migration. Although rare, plate failure may result in a dural tear and spinal cord injury/compression.

CASE DESCRIPTION

In this case, a 61-year-old man with a history of cervical spondylotic myelopathy treated with C3-7 laminoplasty 7 years prior presented to our hospital with severe headaches and electrical-type pain through the left upper and lower extremities. Imaging studies revealed several broken laminoplasty plates and intradural migration of a fragment of the C7 plate.

CONCLUSIONS

We provide recommendations for preventing hinge nonunion because resultant micromotion likely contributed to the plate breakages observed in this patient.

The Efficacy of Ultrasonic Bone Scalpel for Unilateral Cervical Open-Door Laminoplasty: A Randomized Controlled Trial

BACKGROUND

In cervical open-door laminoplasty for cervical myelopathy, a high-speed rotatory drill and rongeurs are used to make unicortical troughs and bicortical openings in the laminae. The lamina is reflected at the trough to enlarge the spinal canal, followed by bone healing on the hinge side to stabilize laminoplasty. The ultrasonic bone scalpel (UBS) has been used due to theoretical advantages including a better hinge union rate, less soft tissue trauma, less neurological injury, and shorter operative time.

OBJECTIVE

To assess the superiority of UBS for hinge union compared to the drill through randomized controlled trial.

METHODS

In 190 randomly allocated cervical myelopathy patients, the trough and opening at the lamina were made using either the drill (n = 95) or UBS (n = 95) during 2015 to 2018. The primary outcome was the hinge union rate on 6-mo postoperative computed tomography. Secondary outcomes included the hinge union rate at 12 mo, the operative time, intraoperative/postoperative bleeding, neurological injury, complications, and clinical outcomes over a 24-mo follow-up.

RESULTS

Hinge union in all laminae was achieved in 60.0% (drill) and 43.9% (UBS) of patients at 6 mo (intention-to-treat analysis; P = .02; odds ratio, 2.1) and in 91.9% (drill) and 86.5% (UBS) at 12 mo. Dural injury only occurred in the drill group (2.1%), and the UBS group showed significantly less intraoperative bleeding (P < .01). The other secondary outcomes did not differ between groups.

CONCLUSION

The hinge union rate was inferior in the UBS group at 6 mo postoperatively, but UBS was efficacious in reducing dural injuries and bleeding.

[All levels miniplate fixation and a modified hybrid fixation method in expansive open-door cervical laminoplasty: a retrospective comparative study]

OBJECTIVE

To retrospectively compare the effect of alternate levels miniplate and anchor fixation with the effect of all levels miniplate fixation in expansive open-door cervical laminoplasty (EOLP).

METHODS

Patients with cervical spondylosis underwent EOLP between July 2015 and June 2016 were included in the study. There were 33 patients in the alternate group (alternate levels miniplate and anchor fixation group) and 34 patients in the miniplate group (all levels miniplate fixation group). Neurological function was evaluated with the Japanese Orthopedic Association (JOA) score and degree of pain was assessed with the visual analogue scale (VAS) score. Basic clinical and surgical data, complication rates and medical costs of the two groups were compared. In addition, radiological examinations were performed pre- and post-operatively and at the final follow-up. Relative imaging data such as anteroposterior diameter (APD), cervical curvature index (CCI) and open angle were collected and compared.

RESULTS

(1) The mean follow-up time was 18.6 months in the alternate group and 18.9 months in the miniplate group. There were no significant differences in operation time, intraoperative blood loss, perioperative complication rates, post-operative hospital stays, VAS scores and neurological recovery rates preoperatively and at the final follow-up between the two groups. (2) Additionally, no obvious differences were observed about CCIs and APDs at the three follow-up time points between the two groups. Post-operative open angles at C4 and C6 in the alternate group were significantly smaller than those in the miniplate group. However, there were no significant differences in C3, C5 and C7 open angles between the two groups post-operatively. Notably, no significant differences were detected about the open angles at all levels between the two groups at the final follow-up. (3) When comparing radiologic data at different time points in each group, CCIs and open angles at each level had no significant differences, but APDs after surgery and at the final follow-up were significantly larger than pre-operative APDs. (4) Total costs in the alternate group were significantly lower than those in the miniplate group.

CONCLUSION

The two surgical methods showed almost the same neurological recovery rates and complication rates. However, use of alternate levels miniplate and anchor fixation in EOLP can reduce medical expenses.

Preoperative severity of facet joint degeneration does not impact the 2-year clinical outcomes and cervical imbalance following laminoplasty

BACKGROUND CONTEXT

The impact of preoperative facet degeneration (FD) on surgical outcomes following laminoplasty has not been established.

PURPOSE

To elucidate the influence of preoperative FD on pre and postoperative clinical symptoms and radiographic parameters.

STUDY DESIGN

Retrospective analysis of prospectively collected data.

PATIENT SAMPLE

A total of 135 consecutive patients who underwent laminoplasty for cervical spondylotic myelopathy with greater than 2 years follow-up.

OUTCOME MEASURES

The cervical Japanese Orthopedic Association score, visual analog scale, Short Form-36, Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire, and radiographic parameters (C7 slope, C2-C7 sagittal vertical axis, C2-C7 lordotic angle, and scoring of FD).

METHODS

FD severity of the bilateral facets of C2-3 to C7-T1 was graded using preoperative computer tomography images. Patients were divided into two quantiles according to the mean score of their FD grading: mild (n=69) and severe FD groups (n=66). The preoperative clinical score and radiographic parameters of the two groups were compared. Variables with p<.05 were included in the multinomial logistic regression model. The changes in clinical scores and radiographic parameters between both groups (from the preoperative to 2-year postoperative period) were compared using a mixed-effect model, after adjusting for age and sex.

RESULTS

Mean age and neck pain visual analog scale were independently associated with FD severity (age: p=.004, neck pain: p=.004). However, the other preoperative clinical scores and radiographic parameters were not significantly different. In terms of the change in clinical scores 2 years postlaminoplasty, no significant differences between the severe and mild FD groups were noted. While the mild FD group had a reduced C2-C7 lordotic angle, the severe FD group demonstrated an increased C2-C7 lordotic angle 2 years postlaminoplasty (p=.044). The change in C7 slope and C2-C7 sagittal vertical axis showed no significant differences.

CONCLUSIONS

Preoperative FD severity did not influence the 2-year surgical outcomes of laminoplasty, in terms of improvement in myelopathy, patient-oriented score of quality of life, physical and mental status, as well as neck pain. Furthermore, preoperative FD severity correlated with neither preoperative cervical imbalance nor balance deterioration after laminoplasty. These results may encourage physicians to consider laminoplasty for patients with cervical spondylotic myelopathy, regardless of the severity of FD.

MRI kinematic analysis of T1 sagittal motion between cervical flexion and extension positions in 145 patients

PURPOSE

Although the T1 vertebra is considered as an important factor of cervical balance, little is known about its motion between flexion and extension. The purpose of present study was to analyze the T1 sagittal motion using kinematic magnetic resonance imaging (kMRI), and to identify factors that relate to T1 sagittal motion.

METHODS

We retrospectively analyzed 145 kMR images taken in weight-bearing neutral, flexion and extension positions. Cervical balance parameters were evaluated in each position. The degree of T1 sagittal motion was defined as [(T1 slope at extension) - (T1 slope at flexion)]. All patients were divided into three groups: Positive group (T1 followed the head motion, T1 sagittal motion > 5°), Stable group (5 ≥, ≥ - 5) and Negative group (T1 moved in the opposite direction from the head motion, > - 5). The groups were compared and multivariate logistic regression analysis was calculated.

RESULTS

There were 57 (40%) patients in the positive, 56 (39%) in the stable and 32 (22%) in the negative group. The positive group had the largest C2-7 sagittal vertical axis in flexion (p < 0.001) and the shortest in the extension (p = 0.023). Similar trends were seen in cranial tilt and cervical tilt. The value of T1 height < 27 mm was a significant independent factor for the negative group (p = 0.008, adjusted odds ratio = 5.958).

CONCLUSION

Based on T1 sagittal motion, 40% of the patients were classified in positive group (the T1 vertebra followed the head motion in flexion and extension), and 20% were classified in the negative group (the T1 vertebra moved in the opposite direction from the head motion). T1 height < 27 mm was a potential predictor of negative group.