Single-door Cervical Laminoplasty Research Articles

Comparison of Clinical Outcomes of Cervical Laminoplasty for Cervical Spondylotic Myelopathy: Double-Door With Lamina Staple, Single-Door With Miniplate, and Double-Door With Spacer-A 2-Year Follow-Up Study.

There were few studies to compare the outcomes of different types of cervical laminoplasties. To compare the clinical outcomes of double-door cervical laminoplasty with lamina staple (double-door staple), single-door cervical laminoplasty with miniplate (single-door miniplate), and double-door cervical laminoplasty with spacer (double-door spacer). The study involved 166 patients with cervical spondylotic myelopathy (CSM). Fifty-two patients underwent double-door staple, 63 patients underwent single-door miniplate, and 51 patients underwent double-door spacer. The clinical outcomes were measured. There was no significant difference in Japanese Orthopedic Association score among the 3 groups ( P > .05). The operation time was significantly shorter in double-door staple and single-door miniplate groups than in the double-door spacer group ( P < .005). The estimated blood loss was significantly more in the single-door miniplate group than in double-door staple and double-door spacer groups ( P < .005). The expansion ratio of cervical intraspinal cross-sectional area decreased in the order of double-door staple > double-door spacer > single-door miniplate. There were no significant differences in the expansion ratio of dural sac cross-sectional area among the 3 groups. Double-door staple, double-door spacer, and single-door miniplate can achieve favorable clinical outcomes for CSM. The blood loss of double-door staple is less than that of single-door miniplate, and the operation time of double-door staple is shorter than that of double-door spacer. The mean expansion ratio of cervical intraspinal cross-sectional area decreased in the order of double-door staple > double-door spacer > single-door miniplate. Overall, double-door staple is a safe and innovative alternative choice for treatment of CSM.

Is there any correlation between the recovery rate of JOA and the increasing of cervical spinal cord area after single-door cervical laminoplasty?

ObjectivesThe aim of the study is to investigate the clinical and radiologic factors represented by the increasing of spinal cord area associated with the prognosis of the patients at long-term follow-up by multivariate analysis after single-door cervical laminoplasty (SDCL). MethodsA total of 115 patients who underwent cervical laminoplasty with miniplate fixation were included from November 2008 to June 2018. The average postoperative follow-up period was 17.3 months (range, 12–105 months). The prognosis of the patients following cervical laminoplasty was evaluated by the recovery rate of Japanese Orthopedic Association (JOA) at the final follow-up. The recovery rate of JOA ≤ 50% were classified as poor prognosis group (PP group) whose prognosis is relatively poor, and those> 50% were classified as good prognosis group (GP group) whose have a better prognosis. The clinical factors including gender, age, duration of symptoms, diagnosis type, blood loss, operative time, pre- and post-JOA score, etc. were recorded. The radiologic factors including sagittal canal diameter (SCD), the cervical curvature index (CCI), the range of motion (ROM), the spinal canal area and the increasing of cervical spinal cord area, etc. were collected before and after operation and measured by X-ray plain and computed tomography (CT) scan images. The univariate analysis and multivariate logistic regression analysis were performed. ResultsThere were 62 patients in PP group and 53 patients in GP group. The multivariate analysis showed that the preoperative (OR=6.875, P = 0.001) and postoperative JOA scores (OR=24.000, P = 0.001), preoperative spinal canal area (OR=2.464, P = 0.023) and the increasing of cervical spinal cord area (OR=5.438, P = 0.001) maybe related factors to the recovery rate of JOA at the final follow-up. ConclusionsThe preoperative spinal canal area, the increasing of cervical spinal cord area, preoperative and postoperative JOA scores play important roles in long-term prognosis after SDCL.

Multivariate analysis of factors associated with spinal cord area in single-door cervical laminoplasty with miniplate fixation

ObjectivesTo explore the factors associated with the increased spinal cord area in single-door cervical laminoplasty (SDCL) with miniplate fixation.MethodsA retrospective study enrolled 83 patients underwent SDCL with miniplate fixation and the patient characteristics such as age, gender, tobacco use, alcohol use, diabetes mellitus, hypertension, diagnosis, operative level, etc., were obtained. The opening angle, door shaft position and spinal canal area of the patients were measured after surgery. The sagittal canal diameter (SCD), the C2–7 Cobb angle, the cervical curvature index (CCI), the range of motion (ROM) and the spinal canal area were measured before and after operation. The increased cervical spinal cord area was also measured before and after surgery, and the correlation between the above indicators and the increased cervical spinal cord area was studied through Pearson’s correlation analysis and multivariate logistic regression analysis.ResultsThere were 34 patients in small spinal cord area increment group (SAI group), 29 patients in middle spinal cord area increment group (MAI group) and 20 patients in large spinal cord area increment group (LAI group). The preoperative diagnosis(P = 0.001), door shaft position (P = 0.008), preoperative spinal canal area (P = 0.004) and postoperative spinal canal area (P = 0.015) were significant different among the 3 groups. The multivariate analysis showed that the preoperative diagnosis (OR = 2.076, P = 0.035), door shaft position (OR = 3.425, P = 0.020) and preoperative spinal canal area (OR = 10.217, P = 0.009) were related to increased spinal cord area.ConclusionsThe preoperative diagnosis, door shaft position and preoperative spinal canal area might be associated with increased spinal cord area after cervical laminoplasty with miniplate fixation. Preoperative symptoms are mostly caused by compression of the spinal cord, so spinal cord area enlargement can bring a better recovery in patients alongside long-term. Spine surgeons should pay more attention to the accuracy of the preoperative diagnosis, the preoperative measurement of spinal canal area and the door shaft position during the operation.

The Rare Occurrence of Reoperation After Cervical Laminoplasty: A 14-Year Retrospective Review of Reoperative Rates at a Single Institution.

Retrospective cohort study. To determine the rate of recurrent or adjacent-level stenosis requiring reoperation after single-door cervical laminoplasty for spondylotic myelopathy at our institution. Adjacent-level stenosis requiring reoperation is a commonly evaluated condition for anterior or posterior arthrodesis, however, there are few studies that evaluate adjacent-level stenosis in the case of cervical laminoplasty. Retrospective review of adults undergoing cervical laminoplasty for spondylotic myelopathy between January 2005 and May 2018 at our institution. Demographics, symptom duration, stenotic levels, preoperative and postoperative Medical Research Council motor, American Spinal Injury Association, modified Japanese Orthopaedic Association scores, and Nurick grade were obtained. Postoperative data included presence of C5 palsy, infection rate, alleviation or persistence of symptoms, and rate of recurrent or adjacent-level stenosis. A total of 102 patients underwent cervical laminoplasty; mean age was 56.7 years (±12.96). Most were men (n=76, 74.5%), with myelopathy (n=64, 63.4%), C4 (n=94, 93.1%), and C5 (n=92, 91.1%) cervical stenosis; mean symptom duration was 55 days (7 d to 2.8 y). Average follow-up was 6.4 months (±3.4). After surgery, there was statistically significant improvement in Nurick grade (3.1±2.2 vs. 2.7±2.4, P=0.002) and modified Japanese Orthopaedic Association score (11.4±3.7 vs. 13.9±3.6, P<0.001); American Spinal Injury Association scores also improved (P<0.001). Rate of postoperative C5 palsy was 7.8% (n=8); postoperative infection rate was 1.96% (n=2). Reoperation rate was 4.9% (n=5); reoperation for recurrent or adjacent-level stenosis was 1.96% (n=2). Recurrent or adjacent-level stenosis requiring reoperation after cervical laminoplasty is rare. Longitudinal studies are needed to verify correlation between motion preservation and incidence of adjacent or recurrent stenosis. Level III-treatment benefits: nonrandomized controlled cohort/follow-up study.

A modified cutting line in the single-door cervical laminoplasty via a computed tomography-based morphological study of the subaxial cervical spine

ObjectiveTo modify the conventional methods of grooving and direction during the single-door cervical laminoplasty (SDCL) in the subaxial cervical spine. MethodsThe distance between the left and the right lamina-lateral mass junction at the upper, middle, and lower levels of each segment (DLL-U, DLL-M, DLL-L), angle between the posterior edge of the vertebral body and the lamina (AVL) and thickness of lamina (TL) were measured in the transverse plane. The parameters of preoperative computed tomography scans of 200 patients who had undergone SDCL were measured. The patients were divided into male and female groups and developmental canal stenosis (DCS) and non-DCS (NDCS) groups. ResultsDLL-M gradually increased from the cranial to the caudal except for C7, and DLL-L > DLL-M > DLL-U in each vertebra. AVL increased from C3 to C7, TL decreased from C3 to C5 and increased from C5 to C7, with both parameters showing no significant differences between the left and right sides. AVL of the DCS group was less than that of the NDCS group (P < 0.01). ConclusionsIn the SDCL, the ideal surgical trough should be several discontinuous lines sloping from top to bottom, rather than a straight line. The abduction angle during drilling should gradually increase from C3 to C7 in the SDCL averaging 40 degrees. This method mentioned above improves the efficiency of the operation with less blood loss as an extended cut into the lateral mass is avoided.

Nomogram for predicting kyphotic deformity after laminoplasty in cervical spondylotic myelopathy patients without preoperative kyphotic alignment

BackgroundKyphotic deformity occurrence after cervical laminoplasty is not rare. Several studies have emphasized the development of postoperative kyphotic deformity (PKD) will impair the functional outcome of cervical laminoplasty. We established and validated a nomogram prediction model for kyphotic deformity after laminoplasty in cervical spondylotic myelopathy patients (CSM) without preoperative kyphotic alignment. MethodsPreoperative and 1-year postoperative data of 369 patients who underwent single-door cervical laminoplasty (SDCL) at the author’s hospital between July 2010 and February 2018 were collected. Using the least absolute shrinkage and selection operator (LASSO) method, significant parameters were selected to develop a nomogram prediction model. The prognostic performance of the model was evaluated using concordance index (C-index) and calibration curve. The discriminatory ability of the prediction model was evaluated by the area under (receiver operating characteristic) curve (AUC). ResultsOf the 369 patients, 31 developed PKD in 1 year after the surgery. Using the LASSO regression, six significant variables composed the final model: age, C2-7 sagittal vertical axis, C7 slope, C2-7 angle, flexion range of motion and operation level were selected. The AUC of the nomogram was 0.771. The C-index for the prediction nomogram was 0.771 (95 % CI: 0.672−0.870). The calibration curve also indicated good consistency. ConclusionA nomogram for predicting PKD after SDCL was established and validated. For patients evaluated by this model with predictive high risk of developing postoperative kyphosis, an alternative approach to the subaxial cervical spine such as anterior surgery should be considered.

Clinical Investigation of the Association of Opening Size with Sagittal Canal Diameter Based on Single-Door Cervical Laminoplasty.

BackgroundMany clinical studies have assessed the association of laminoplasty opening size (LOS) with sagittal canal diameter (SCD) based on single-door cervical laminoplasty (SDCL). Nevertheless, the “worn-off” lamina extracted in SDCL was neglected in these reports. We aimed to develop a simple mathematical model to analyze the relationship between the effective LOS and SCD, taking into consideration the worn-off lamina.Material/MethodsA total of 106 patients treated by SDCL at our hospital were included in this study. Pre-operative and post-operative SCDs were assessed using a picture archiving and communication system (PACS) based on computed tomography scans. Mini-plate sizes as well as drill bit diameters were recorded in detail in order to determine the effective LOS for each vertebral lamina involved.ResultsSCD in all patients was increased significantly after SDCL (P<0.01). A linear correlation was found between effective LOS and the post-operative SCD increment from C3 to C7 (R2>0.933, P<0.001). The 12 mm mini-plate was most often used in SDCL, accounting for 64.45% of all cases, whereas 10 mm and 16 mm mini-plates were the least used, accounting for 3.85% and 3.00%, respectively.ConclusionsThere is a strong linear correlation between effective LOS and the post-operative SCD increment. The SCD was increased by about 0.5 mm per mm increase in effective LOS. Thus, post-operative SCD could be precisely calculated and predicted, enabling the selection of optimal mini-plate prior to SDCL.

A new method for calculating the desired laminoplasty opening size based on the target sagittal canal diameter before single-door cervical laminoplasty.

To build a mathematical model which could calculate the desired laminoplasty opening size (LOS) based on the target sagittal canal diameter (SCD) before single-door cervical laminoplasty (SDCL) when taking the effects of surgery drill into consideration. The model was based on geometric analysis on deformation of spinal canal; the formula was derived and characterized as: y (mm) = 2 [Formula: see text] × sin(β/2) = c - d (y is the size of LOS, [Formula: see text] the size of transverse canal diameter, β the size of laminoplasty opening size, c the size of mini-plate and d the diameter of the drill bit used during the surgery operation). The parameters of pre- and postoperative computed tomography scans of 20 patients who had undergone SDCL were measured by the picture archiving and communication system (PACS) software and a new instrument named as Lei's ruler, respectively. The effects of surgery SDCL were very significant; for each patient, the SCD was enlarged dramatically after the surgery (P < 0.01). The differences between the data obtained by PACS and Lei's ruler were no statistically significant (P > 0.05). According to the derived formula, the 95% confidence intervals of SCD after the surgery were within the range of 14mm and 14.5mm. Applying the mathematical model and derived formula, the desired LOS could be calculated according to the target SCD which could help the surgeon select an optimum mini-plate before SDCL. At the same time, a new measuring device named Lei's ruler is designed for the convenience of the derived formula. These slides can be retrieved under Electronic Supplementary Material.

Relationship of actual laminoplasty opening size and increment of the cross-sectional area based on single-door cervical laminoplasy.

Background:Amounts of clinic research have been performed to investigate the increment of cross-sectional area in single-door cervical laminoplasty (SDCL). However, no one has taken the effects of surgery drill into consideration.Methods:A mathematical model was built to investigate the relation of actual laminoplasty opening size (LOS), the transverse canal diameter (TCD), and the increment of cross-sectional area in SDCL). The model was based on geometric analysis on deformation of spinal canal; the relation was derived and characterized as: , where a is the TCD, b the actual LOS, c the size of mini-plate, and d is diameter of the surgery drill bit. In the equation, the related variables would be measured to estimate the increment of cross-sectional area before the surgery. In the current research, 25 patients authorized to use their CT scans of C3∼C7 as the subject samples.Results:The effects of surgery SDCL were very significant; for each patient, the cross-sectional area was enlarged dramatically after the surgery (P < .01). On the contrary, the difference between the cross-sectional area obtained by the equation and that measured by software was statistically negligible (P > .05), which confirmed the reliability of the modeling equation.Conclusions:Before the SDCL, increment of the cross-sectional area can be estimated by the above-mentioned modeling equation with a high-level reliability. This method ensures the optimum selection of mini-plate before operation for each patient.

Single-door cervical laminoplasty using titanium miniplates alone.

To review outcome of 29 patients who underwent single-door cervical laminoplasty for myelopathy using titanium miniplates alone. Records of 20 men and 9 women aged 35 to 79 (mean, 64.3) years who underwent single-door cervical laminoplasty for myelopathy using titanium miniplates alone were reviewed. A total of 125 laminae were opened; 97 of them were fixed with a titanium miniplate. In 19 patients, a 20-hole titanium miniplate bent to the contour of a lamina was used and fixed into 3 laminae at alternate levels. In the remaining 10 patients, the pre-contoured ARCH Laminoplasty System was used and fixed into all laminae. In most patients, screw fixation was unicortical, and no spacer or bone graft was used. The mean follow-up duration was 4 (range, 2-9) years. At one-year follow-up, the mean Japanese Orthopaedic Association (JOA) score improved from 9.2 to 13.2 (p<0.001). The mean JOA recovery rate was 64%. No patient had neurological deterioration. The mean anteroposterior diameter increased from 14.3 mm to 19.7 mm; the mean increase was 6.1 mm in the plated laminae and 5.3 mm in the unplated laminae (p=0.11). Out of the 125 laminae, there were 2 hinge non-unions in the unplated laminae, and 2 screw pullouts (not associated with plate loosening). No patient had penetration into the vertebral foramen or neuroforamen. Spring-back closure occurred in 5 (18%) of the 28 unplated laminae, with a mean of <3 mm loss of the initial expansion. Two patients developed transient C5 palsy presenting as shoulder abduction weakness. One patient had a delayed dural tear due to a sharp spike at the edge of the opened C6 lamina. Single-door cervical laminoplasty using miniplates alone is a safe technique and achieves a high hinge union rate, good canal expansion, and neurological recovery.