Single Open-door Laminoplasty Research Articles

The clinical efficacy of laminectomy fusion fixation and posterior single open-door laminoplasty in the treatment of multilevel cervical ossification of the posterior longitudinal ligament (OPLL): a retrospective study

BackgroundTo compared the clinical efficacy of two surgical methods, posterior laminectomy fusion fixation, and posterior single open-door laminoplasty, in treating multilevel cervical ossification of the posterior longitudinal ligament (OPLL).MethodsThe study retrospectively included 102 patients treated between December 2016 and December 2020. The patients were included into an observation group (56 cases) treated with total laminectomy and lateral screw fixation, and a control group (46 cases) treated with single open-door laminoplasty.ResultsAfter 24 months, both groups showed significant improvement in Japanese Orthopaedic Association (JOA) scores and Visual Analogue Scale (VAS) scores, indicating better clinical symptoms and functional recovery. There was no significant difference in preoperative JOA and VAS scores between the two groups (P > 0.05). At 24 months after surgery, there was no significant difference in JOA and VAS scores between the two groups (P > 0.05). However, the observation group had a significantly higher cervical curvature index (CCI) and lower range of motion (ROM) of the cervical spine compared to the control group (P < 0.05). The CCI in control group was lower than before surgery, while the CCI in observation group was higher than before surgery, and CCI in the control group was considerably lower than that in the observation group (P < 0.05). The complication rate was lower in the control group, with fewer cases of axial symptoms, fifth cervical nerve root palsy, and overall complications. The overall complication rate was 25.0% (14/56) in the observation group and 10.8% (5/46) in the control group (P < 0.05).ConclusionsBoth posterior laminectomy fusion fixation and posterior single open-door laminoplasty yield positive outcomes in improving clinical neurological function, cervical curvature, range of motion of the cervical spine, and cervical sagittal balance. Although open-door laminoplasty is less effective than total laminectomy in maintaining CCI and sagittal balance, it excels in preserving cervical range of motion, less surgical trauma and complications. Thus, open-door laminoplasty may be a suitable first-choice treatment for multi-segmental cervical OPLL, especially for patients with lordotic cervical spine physiological curvature.

Progress on the impact of adjacent vertebral arch after single open door laminoplasty

Single-door laminoplasty has been widely used in the treatment of multisegment cervical myelopathy, with the clinical advantages of decompression of the spinal cord, relieving preoperative neurological symptoms or signs, and maintaining cervical mobility. However, in clinical work, patients with limited cervical spine activity after single open door laminoplasty are often encountered, and the direct contact with the adjacent vertebral arch can be observed in the postoperative X-ray of the anterior and lateral cervical spine, which is called the adjacent vertebral arch bone impact, which is one of the important causes of the limited cervical spine movement. In recent years, there have been many reports on the prevention of bone impact, although the short-term clinical effect is significant, but long-term clinical efficacy to be further study, and the cause and the pathogenesis of bone impact is no consensus, this paper on the surgery of adjacent vertebral arch impact epidemiology, biomechanics, clinical performance, surgical effect and improvement.

A Retrospective Cohort Study of a Modified Open-Door Laminoplasty With Reconstruction of The Cervical Posterior Ligamental Complex to Decrease Axial Pain in Cervical Spondylotic Myelopathy

Background: Cervical spondylotic myelopathy patients with multiple segments are usually treated with surgery via the posterior approach, but expansive open laminoplasty (ELAP) often results in heavy, rigid, and acid bilge feelings in the neck, shoulder, and back, collectively known as axial symptoms. To evaluate the effect of modified posterior cervical ligament complex reconstruction and single-door laminoplasty with titanium plate fixation on postoperative axial symptoms in patients. Methods: We conducted a retrospective study including 132 cases of cervical spondylotic myelopathy at our institute from June 2016 to March 2018. The patients who conformed to the inclusion criteria were randomly divided into two different surgical groups by by the surgeons. Gender, age, operation time, intraoperative blood loss, post-operative drainage volume, and follow-up time, Visual analogue scoring (VAS), cervical curvature index (CCI) and the cross-sectional area of the posterior cervical muscles of the two groups were recorded. Results: There was statistical significance in the incidence of axial pain 3 months after surgery (P = 0.001), 6 months after surgery (P = 0.006), and 1 year after surgery (P = 0.015). Compared to group b, the VAS score in group A was decreased one month (P &lt;0.0001), 3 months (P=0.0001), 6 months(P=0.0076), and 1 year(P=0.0085) after surgery. The CCI and the posterior cervical muscle area also differed significantly between the two groups (P &lt; 0.0001). Conclusions: Modified single open-door laminoplasty could relieve cervical axial pain in patients with cervical spondylotic myelopathy

A Retrospective Cohort Study of a Modified Open-Door Laminoplasty With Reconstruction of The Cervical Posterior Ligamental Complex to Decrease Axial Pain in Cervical Spondylotic Myelopathy

Background: Cervical spondylotic myelopathy patients with multiple segments are usually treated with surgery via the posterior approach, but expansive open laminoplasty (ELAP) often results in heavy, rigid, and acid bilge feelings in the neck, shoulder, and back, collectively known as axial symptoms. To evaluate the effect of modified posterior cervi- cal ligament complex reconstruction and single-door laminoplasty with titanium plate fixation on postoperative axial symptoms in patients. Methods: We conducted a retrospective study including 132 cases of cervical spondylotic myelopathy at our institute from June 2016 to March 2018. The patients who conformed to the inclusion criteria were randomly divided into two different surgical groups by by the surgeons. Gender, age, operation time, intraoperative blood loss, post-operative drainage volume, and follow-up time, Visual analogue scoring (VAS), cervical curvature index (CCI) and the cross-sec- tional area of the posterior cervical muscles of the two groups were recorded. Results: There was statistical significance in the incidence of axial pain 3 months after surgery (P = 0.001), 6 months after surgery (P = 0.006), and 1 year after surgery (P = 0.015). Compared to group b, the VAS score in group A was decreased one month (P &lt;0.0001), 3 months (P=0.0001), 6 months(P=0.0076), and 1 year(P=0.0085) after surgery. The CCI and the posterior cervical muscle area also differed significantly between the two groups (P &lt; 0.0001). Conclusions: Modified single open-door laminoplasty could relieve cervical axial pain in patients with cervical spon- dylotic myelopathy

Cervical single open-door laminoplasty with or without local lateral mass screw fixation and fusion to treat cervical spinal cord injuries accompanied by segmental spinal canal stenosis.

Retrospective. To investigate the efficacy of cervical single open-door laminoplasty with and without local lateral mass screw fixation and fusion as treatments for cervical spinal cord injuries accompanied by multisegmental spinal canal stenosis. The Second Affiliated Hospital, School of Medicine, Zhejiang University. Of all enrolled patients, 42 formed a stable group who underwent cervical single open-door laminoplasty alone and 14 formed an unstable group who underwent the procedure combined with lateral mass screw fixation and fusion. Neurological function was evaluated before surgery, at discharge, and at final follow-up using the American Spinal Cord Injury Association (ASIA) impairment scale and the Japanese Orthopedic Association (JOA) score. ASIA scores reflected improved neurological function in 52.5% of the stable group (15 with grade-D and 4 with grade-A injuries did not improve) and 45.5% of the unstable group (3 with grade-D and 3 with grade-A injuries did not improve). Postoperative JOA scores reflected 19.1% ± 21.6% improvement in the stable group and 18.6% ± 18.4% improvement in the unstable group (P > 0.05). Final follow-up JOA scores reflected 49.2% ± 31.7% improvement in the stable group and 47.1% ± 39.2% improvement in the unstable group (P > 0.05). Laminoplasty combined with local fusion aided the treatment of unstable cervical spinal cord injuries and spinal stenosis. Such stenosis is the main pathological factor causing multiple spinal cord compressions in patients with cervical spinal cord injuries.

A case-control study:the clinical efficacy of total laminectomy with lateral mass screw fixation and single open-door laminoplasty for cervical spinal cord injury without fracture and dislocation

To compare the clinical effects of total laminectomy with lateral mass screw fixation and single open-door laminoplasty in the treatment of cervical spinal cord injury without fracture and dislocation. The clinical data of 75 patients with cervical spinal cord injury without fracture and dislocation treated from December 2014 to April 2020 were retrospectively analyzed, including 65 males and 10 females, aged from 33 to 83 years old with an average of (60.1±11.4) years. According to surgical method, the patients were divided into observation group (36 cases) and control group (39 cases). The observation group was treated with C3-C6 single open-door laminoplasty. In the control group, the C3-C6 whole lamina was opened by "uncovering", and the lateral mass screw was fixed and fused. The general conditions including operation time, intraoperative blood loss, hospital stay and complications such as axial pain, cerebrospinal fluid leakage, postoperative C5 nerve palsy were recorded. Visual analogue scale(VAS), Nurick pain scale, Japanese Orthopaedic Association(JOA) scores and American Spinal Injury Association(AISA) injury scale were used to evaluate the improvement of clinical symptoms and related functional recovery 12 months after operation. There were no statistically significant differences in operation time, intraoperative blood loss and hospital stay between two groups(P>0.05). There were statistically significant differences in JOA, VAS, ASIA and Nurick scores of the all patients between 12 months after surgery and before surgery (P<0.05), and there was no significant difference between groups. There was significant difference in the incidence of C5 nerve root palsy and axial pain between two groups(P<0.05), but there was no significant difference in the complications of cerebrospinal fluid leakage between two groups (P>0.05). Total laminectomy with lateral mass screw fixation and single open-door laminoplasty in treating cervical spinal cord injury without fracture and dislocation can obtain satisfactory results in restoring nerve function, alleviating pain and improving daily behavior, but single open-door laminoplasty has the advantages of less trauma and low incidence of complications.

Application of Quality Control Circle Activities in Improving the Integrity of Equipment Preparation for Posterior Cervical Surgery

Objective: To explore the clinical effects of quality control circle (QCC) activities on the preparation of instruments, team cooperation and clinical satisfaction of posterior cervical surgery. Methods: The clinical randomization table was used to select 100 patients who underwent posterior single open-door laminoplasty in the Department of orthopedics of our hospital from January 2020 to January 2021 as the study subjects. In the experimental group, quality control circle activities were used to prepare the surgical instruments before operation, including 32 males and 18 females, with an average age of 58.3 ± 10.5 years; The control group did not use quality control circle activities to prepare the surgical instruments before operation, including 27 males and 22 females, with an average age of 60.5 ± 9.8 years. First, the "quality control circle" activity group was established to carry out quality control circle activity steps such as theme selection, plan formulation, status analysis, goal establishment, problem rectification, specific implementation, effect evaluation and effect evaluation. The database was established by software, and the t-test and chi square test were used for statistical analysis to compare the pre-operative instrument preparation rate of the two groups of patients undergoing cervical posterior single open-door laminoplasty. Finally, the improvement of team consciousness, nursing knowledge, nursing quality, consciousness response and other qualities of all circle members in the experimental group before and after the use of quality control circle activities were analyzed, and the clinical satisfaction of patients and their families, anesthesiologists and chief surgeons with the operation and the integrity rate of equipment preparation were compared between the two groups. Results: The overall integrity rate of the instruments in the experimental group was 90%, and the overall integrity rate of the instruments in the control group was 74%. The integrity rate of the instruments in the experimental group was significantly higher than that in the control group (P &lt; 0.01). After the implementation of quality control circle activities, the team consciousness, nursing knowledge, nursing quality and consciousness reaction of the circle members in the experimental group were significantly improved compared with those before the implementation of quality control circle activities, and the difference between the two groups was statistically significant (P &lt; 0.01). The overall satisfaction of patients and their families, anesthesiologists, and chief surgeons in the experimental group was 92%, 88%, and 90%, and that of the control group was 76%, 68%, and 74%, respectively. The overall satisfaction of the experimental group was significantly higher than that of the control group (P &lt; 0.05); The integrity rate of surgical instruments preparation in the experimental group was 90%, and that in the control group was 74%. The experimental group was significantly higher than the control group (P &lt; 0.01). Conclusion: The application of quality control circle activities can improve the integrity of instrument preparation for posterior cervical surgery, improve the satisfaction of patients, family members and medical staff, and improve the quality of surgical care.

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

A retrospective case series. 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. 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. 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. 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. 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.

Atlantoaxial subluxation due to os odontoideum combined with cervical spondylotic myelopathy: case report and literature review

Study Design: This was a case report and literature review Objective: We describe a case of os odontoideum combined with cervical spondylotic myelopathy (CSM), both of which require surgical treatment. Summary of Background Data: Cervical spondylotic myelopathy is often a disease of the older population, while os odontoideum is a well known disease mainly diagnosed in children and young adults but rarely in the middle-aged population. Os odontoideum combined with cervical spondylotic myelopathy, both of which require surgical treatment is even more rare, there was only one such case in the literature. Methods: We describe a 68-year-old male who underwent C1–C2 posterior screw-rod fixation for os odontoideum and cervical posterior single open-door laminoplasty for cervical spondylotic myelopathy. Results: Twelve months after surgery, the patient showed improvement and the plain radiographs showed no loss of correction or instrumentation failure. Conclusions: To our best knowledge, this is the second case of surgical stabilization for both cervical spondylotic myelopathy and myelopathy atlantoaxial subluxation due to os odontoideum.

Short-term curative effects of ARCH titanium plate fixation combined with expansive single open-door laminoplasty in treating cervical spondylotic myelopathy

To evaluate the short-term curative effects of ARCH titanium plate fixation combined with expansive single open-door laminoplasty (EOLP) in treating cervical spondylotic myelopathy (CSM). EOLP with ARCH titanium plate as internal fixation material was applied in 32 patients with CSM from January to December 2016. There were 23 males and 9 females with an average age of 64.5 years ranging from 39 to 82 years. The course of disease ranged from 6 to 24 months with an average of 13.1 months. The clinical efficacy was evaluated by Japanese Orthopaedic Association (JOA) scoring method, which included upper and lower limb motor function, limb sensory function and bladder function. The sagittal diameter of the narrowest segment of vertebral canal was measured by imaging data before operation and 6 months after operation, and the improvement rate was calculated to determine the decompression effect. All the patients were followed up from 6 to 20 months with an average of 12.2 months. Preoperative symptoms of 32 patients were improved to varying degrees, the JOA score increased from 9.78±1.34 before operation to 12.94±1.16 at 6 months after operation, the improvement rate of JOA was(44.09±11.06)% (P<0.01). The spinal canal was significantly enlarged, the sagittal diameter of the narrowest vertebral canal was increased from (8.47±0.60) mm preoperatively to (12.51±0.78) mm 6 months postoperatively, the improvement rate was (48.27±11.81)% (P<0.01). No loosening, displacement, rupture or "re-closure" of the internal fixator was found during the follow-up. ARCH titanium plate fixation combined with EOLP in the treatment of CSM can significantly reduce the possibility of "re-closure" and other related postoperative complications and the short-term clinical efficacy is satisfactory.

Surgical Outcomes After Anterior Controllable Antedisplacement and Fusion Compared with Single Open-Door Laminoplasty: Preliminary Analysis of Postoperative Changes of Spinal Cord Displacements on T2-Weighted Magnetic Resonance Imaging

This retrospective cohort study aimed to investigate the change of spinal cord displacements and the occurrence of C5 palsy between anterior controllable antedisplacement and fusion (ACAF) (group A) and single open-door laminoplasty (group L). From January 2016 to December 2017, a total of 80 patients with cervical ossification of the posterior longitudinal ligament (OPLL) were enrolled. All patients underwent computed tomography and magnetic resonance imaging. The types and extent of OPLL, spinal cord rotation, deviation angle, and distance between the vertebral arteries line and spinal cord (DVS) were measured. Patients with postoperative C5 palsy were recorded. Neurologic function was evaluated by Japanese Orthopaedic Association (JOA) score. Three days after surgery, patients in group A had better recovery (6.7° ± 2.4°) of spinal cord rotation than group L (3.1° ± 0.8°; P < 0.05). Deviation angle showed similar changes to spinal cord rotation. At the final follow-up, patients in group A had decreased DVS (11.0 ± 0.7 mm), whereas patients in group L had increased DVS (15.1 ± 0.8 mm) compared with preoperation (P < 0.05). Five patients (1in group A and 4 in group L) developed postoperative C5 palsy (P > 0.05). Patients in group A had a higher JOA score at the final follow-up than those in group L (P < 0.05). ACAF could achieve in situ decompression in terms of spinal cord rotation, deviation angle, and spinal cord shift with better clinical outcomes and relatively lower incidence of C5 palsy compared with single open-door laminoplasty.

Clinical indicators of surgical outcomes after cervical single open-door laminoplasty assessed by the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire

Retrospective cohort study. The old-version JOA score for cervical myelopathy (CM) is an evaluation system performed by medical providers that focuses only on neurological function. The purpose of this study was to evaluate patient-reported outcomes using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), and to clarify clinical factors that affect the therapeutic effectiveness for CM. Single institute in Japan. We reviewed surgical outcomes for 126 CM patients who were treated by single open-door laminoplasty and were followed at least 2 years. We assessed clinical information, JOACMEQ, JOA scores, and radiographic parameters. Patients were grouped according to effective or ineffective surgical outcomes as defined by the JOACMEQ using logistic regression analyses. Laminoplasty resulted in functional improvement in the cervical spine and extremities for 40-50% of the patients, while bladder function showed only minimal recovery. Multivariable analyses revealed that a significant postoperative reduction in neck or shoulder pain influenced the effective functional recovery of the cervical spine. A reduction in arm or hand pain favorably affected the postoperative upper extremity function. Lower age and a postoperative decrease in limb pain were correlated with significantly improved function of the lower extremities. A postoperative reduction in arm pain enhanced the QOL recovery. The JOACMEQ makes it possible to analyze multiple aspects of surgical outcomes for patients who undergo cervical spine surgery. Open-door laminoplasty did not provide favorable results for some patients, which highlights the importance of assessing the indications for this procedure and managing postoperative pain.

Analysis of influencing factors the postoperative axial symptoms of cervical single open-door laminoplasty

To explore the influencing factors and possible mechanism of axial symptoms(AS) after C₃-C₇ single open-door laminoplasty in patients with chronic compression cervical myelopathy. The clinical data of 32 patients with multi-segment chronic compression cervical cord disease treated by C₃-C₇ single open-door laminectomy from May 2012 to July 2016 were retrospectively analyzed. Including cervical spondylotic myelopathy of 14 cases, developmental cervical stenosis complicated with cervical myelopathy of 8 cases, ossification of posterior longitudinal ligament(OPLL) of 10 cases. There were 17 males and 15 females, aged from 47 to 82 years old with an average of 57.46 year, the course of disease was 5 to 35 months with an average of 22.4 months. The opening angle(OA), cervical curvature angle(CA), preoperative spinal cord compression rate(PSCR) and postoperative spinal cord shift (PSCS) were recorded. After 2 weeks of surgery, determining whether occurred an AS condition according to the AS assessment criteria, the patients were divided into a axial symptom group and a non-axial symptom group, the general data and imaging parameters of the two groups were compared and the factors that may be postoperative AS were analyzed by binary Logistic regression analysis. At 2 weeks after operation, 13 patients occurred AS. There was no significant difference in gender, age and course of disease between axial symptom group and a non-axial symptom group (P>0.05). In axial symptom group, OA was(36.76±9.35)°, CA was(11.53±4.36)°, PSCR was(27.83±1.72)%, PSCS was (3.17±0.81) mm, while in non-axial symptom group, above items were (33.03±10.52)°, (7.71±4.73)°, (25.16±3.59)%, (2.43±0.95) mm, respectively, there was significant difference in CA, PSCR, PSCS between two groups(P<0.05), and there was no significant difference in OA between two groups(P>0.05). The results of the binary Logistic regression analysis of 3 parameters(OA, PSCR, PSCS) and AS showed OA and PSCR were eliminated in dependent variables, and the partial regression coefficient of PSCR was 0.311, and P=0.031. CA, PSCR, and PSCS are related influencing factors of AS, and PSCS is a high risk factor for AS. C₄,₅ nerve traction caused by posterior spinal movement, postoperative dural self-expansion causes greater traction of the spinal cord, excessive deformation of the cervical spinal cord causes autonomic nerve damage or necrosis that dominates blood vessels may be the pathogenesis of AS, but this is only a theoretical inference, and further improved experiment is necessary to verify it in the future.

Effect of the proximal level on post-laminoplasty loss of lordosis

To analyze the effect whether or not retaining muscle ligament complex of C2 attachment on cervical spine kyphotic deformity after single open-door laminoplasty. A total 40 patients with cervical spondylotic myelopathy underwent single open-door laminoplasty from February 2011 to June 2014 were retrospectively analyzed. Of them, single open-door for C₃-C₆ was 40 cases (group A), including 28 males and 12 females, with an average age of (68.4±9.3) years old;and single open-door for C₄-C₆ plus C₃ laminectomy decompression (in order to protect the muscle ligament complex of C₂ attachment) was 40 cases (group B), including 26 males and 14 females, with an average age of (66.8±8.4) years old. Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS), Cobb angle of sagittal plane from C₂-C₇, cervical range of motion were used to evaluate effects before operation and at the latest follow-up. All the patients were followed up from 24 to 31 months with an average of(26.5±3.4) months. There was no significant differences in VAS, JOA scores and cervical range of motion before surgery between two groups (P>0.05) and all above items were significantly improved at the latest follow-up (P<0.05), but there was no significant difference between two groups(P>0.05). There was no significant difference in cervical Cobb angle before surgery between two groups(P>0.05), and postoperative Cobb angle had obviously improved in two groups(P<0.05), but the improvement of group B was better than that of group A. Starting the laminoplasy on C₄ level and retainning the muscle ligament complex of C₂ attachment can obviouly decrease cervical spine syphotic deformity.

Combining K-line to analyse the relationship between cervical range of motion of patients with ossification of cervical posterior longitudinal ligament and surgical prognosis

Combining K-line (the connecting line of the midpoint of C₂ and C₇ spinal canal on the cervical lateral X-ray film) to analyze the relationship between cervical range of motion of patients with ossification of posterior longitudinal ligament (OPLL) and surgical prognosis. A total 42 patients with ossification of cervical posterior longitudinal ligament underwent cervical posterior single open-door laminoplasty between April 2014 and March 2017 were retrospectively ananyzed. The patients were dividing into K-line (+) group and K-line (-) group according to the position realationship of OPLL and K-line. The lesion of ossification of the posterior longitudinal ligament was not over than the K-line known as K-line (+). Conversely, the lesion of ossification of the posterior longitudinal ligament crossing the K-line was called K-line (-). Preoperative and postoperative 3 months JOA scores were observed, and postoperative 3 months JOA improvement rate were computed to assess patient's neurological function recovery. Preoperation and postoperative 3 months, OPLL occupation ratio (OOR), cervical lordotic angles (CLA) and cervical lordotic value (CLV) were measured respectively. The realationship between postoperative neurologic functional recovery in patients of CLV>0 group and CLV<=0 group was evaluated in different K-line subgroups. For the patients in K (+) group and K (-) group, preoperative CLA were (14.7±9.6)° and (-6.4±9.5)°(P<0.05) respectively, postoperative at 3 months CLA were (14.0±8.0)° and (-1.4±10.4)°(P<0.05) respectively; preoperative JOA scores were 10.9±3.2 and 11.2±2.5 (P>0.05) respectively, postoperative at 3 months JOA scores were 14.2±1.8 and 12.6±2.2 (P<0.05) respectively, and postoperative at 3 months JOA score improvement rate were (54.7±17.6)% and (25.5±15.7)%(P<0.05) respectively. In the K-line (+) group, there were 29 patients in CLV>0 group at 3 months after operation, with improvement rate of (52.3±17.2)%, and 4 patients in CLV<=0 group, with improvement rate of (72.2±7.8)%. The improvement rate of the patients in CLV<=0 group was significantly better than that of the patients in CLV>0 group (P<0.05). No matter whether the ossification of cervical posterior longitudinal ligament was classified as K-line (+) or K-line (-), the cervical posterior single open-door laminoplasty can improve the neurological symptoms of patients, especially the patients in the K-line(+) group with better prognosis. The patinets in K-line(+) group, when postoperative at 3 months CLV>0, their improvement rate was lower than that of the patients with postoperative at 3 months CLV<=0.

Application of ultrasonic bone curette in posterior cervical single open-door laminoplasty

To investigate the safety and reliability of ultrasonic bone curette in posterior cervical single open-door laminoplasty. The clinical data were retrospectively analyzed, from 193 patients who underwent single open-door laminoplasty (C 3-7) from January 2012 to January 2016. The patients were divided into three groups according to different instruments: posterior single open-door laminoplasty was performed with ultrasonic bone curette in 61 cases (group A), with bite forceps in 73 cases (group B), and with micro-grinding drill in 59 cases (group C). There was no significant difference in gender, age, the course of disease, underlying disease and preoperative Japanese Orthopedic Association (JOA) score, visual analogue scale (VAS) between groups ( P>0.05). The operative time, intraoperative blood loss, drainage volume at 48 hours, JOA score, improvement rate, VAS and perioperative com-plication were compared. The operative time, intraoperative blood loss, and drainage volume at 48 hours of group A were significantly less than those in groups B and C ( P<0.05), but there was no significant between groups B and C ( P>0.05). The follow-up time was 12-21 months (mean, 14.6 months) in group A, 24-36 months (mean, 27.5 months) in group B, and 28-47 months (mean, 38.1 months) in group C. There were no cerebrospinal fluid leakage and incision infection in three groups. No complications of internal fixation loosening and rupture occurred during the follow-up. Rediating pain occurred in 6 cases of group A, 8 cases of group B, and 6 cases of group C, and was cured at 1 week after dehydration and physical therapy. No nerve root palsy was found in three groups. Fracture of portal axis occurred in 5 cases (7 segments) of group B and was fixed by micro titanium plate. The JOA score and VAS score at last follow-up were significantly improved when compared with preoperative scores in three groups ( P<0.05); there was no significant difference in JOA score and improvement rate and VAS score between groups ( P>0.05). It is safe and reliable to use the ultrasonic bone curette in posterior cervical single open-door laminoplasty. It can shorten the operative time and has similar clinical curative effect to the traditional operation, and the lateral rotation of the lamina can be avoided.

Three dimensional finite element model of a modified posterior cervical single open-door laminoplasty

Objective: To build a three-dimensional finite element models of a modified posterior cervical single open-door laminoplasty with short-segmental lateral mass screws fusion. Methods: The C(2)-C(7) segmental data were obtained from computed tomography (CT) scans of a male patient with cervical spondylotic myelopathy and spinal stenosis.Three-dimensional finite element models of a modified cervical single open-door laminoplasty (before and after surgery) were constructed by the combination of software package MIMICS, Geomagic and ABAQUS.The models were composed of bony vertebrae, articulating facets, intervertebral disc and associated ligaments.The loads of moments 1.5Nm at different directions (flexion, extension, lateral bending and axial rotation)were applied at preoperative model to calculate intersegmental ranges of motion.The results were compared with the previous studies to verify the validation of the models. Results: Three-dimensional finite element models of the modified cervical single open- door laminoplasty had 102258 elements (preoperative model) and 161 892 elements (postoperative model) respectively, including C(2-7) six bony vertebraes, C(2-3)-C(6-7) five intervertebral disc, main ligaments and lateral mass screws.The intersegmental responses at the preoperative model under the loads of moments 1.5 Nm at different directions were similar to the previous published data. Conclusion: Three-dimensional finite element models of the modified cervical single open- door laminoplasty were successfully established and had a good biological fidelity, which can be used for further study.

Relationship between the prediction of the opening angle and the increased value of cross-sectional area in single open-door laminoplasty

To evolve the formula of relationship between opening angle of laminoplasty and the increased value of cross-sectional area, and to predict the opening angle according to the opening size of lanminoplasty. From January 2013 to December 2015, 26 patients underwent single open-door laminoplasty in C₃-C₇. Among them, 10 patients with ossification of posterior longitudinal ligament, there were 6 males and 4 females, aged from 39 to 58 years old with an average of 49.2 years; and 16 patients with cervical spondylotic myelopathy, there were 10 males and 6 females, aged from 40 to 58 years old with an average of 50.2 years. Through the changes of spinal canal shape between preoperation and postoperation to set up the regular geometric model, and to deduce the formula of the relationship between the opening angle of laminoplasty and the increased value of cross-sectional area, and predict the formula of opening angle. According to the preoperative and postoperative CT scan, the needed parameters were measured, and were substituted in the above formula to get the change of cross-sectional area before and after operation, predicting the opening angle of laminoplasty. The differences between the change of cross-sectional area before and after operation, predictive the opening angle of laminoplasty and practical measured data were analyzed by statistical methods, thus to verify the feasibility of formula in practical application. All imaging data of 26 patients were obtained. There were significant differences in changes of cross-sectional areas in every patients (laminoplasty in C₃ to C₇) before and after operation in the same segment(P<0.01). The increasing extent in cross-sectional areas was gradually diminished following the opening angle increasing. There was no significant difference between the opening angle attained by formula and the data measured by software in the same segment(P>0.05). Increment of cross-sectional areas following C₃-C₇ laminoplasty can be accurately attained and the opening angle can also be predicted by a certain formula, which can help surgeons to attain the accurate opening angle and reduce the postoperative complications.

Outcomes and related factors of C₅ nerve root palsy after cervical posterior single open-door laminoplasty

To analyze the clinical outcomes and related factors of C₅ palsy following cervical laminectomy in treating multi-segments cervical spondylotic myelopathy. From January 2010 to June 2014, 80 patients with spondylotic myelopathy underwent C₃-C₆ open-door laminoplasty(group A) and 80 patients C₄-C₆ open-door laminoplasty (group B). The mean age was (68.4±9.2) years (44 males and 36 females) in group A and the mean age was (66.8±8.9) years (48 males and 32 females) in group B. Japanese Orthopaedic Association(JOA) score, Visual Analogue Score, incidence of C₅ palsy, time of onset, grade of muscle weakness, other accompanying cervical nerve root palsies, recovery time were used to evaluate clinical effects before operation and at last follow-up. Radiographically, changes of Cobb angle of sagittal plane from C₂-C₇, cervical range of motion, minimal spinal cord diameter on MRI were analyzed before operation and at last follow-up. All the patients were followed up from 6 to 15 months with an average of (12.4±3.2) months. No obvious differences were observed between change of VAS of cervical and upper limb, JOA, Cobb angle, cervical range of motion, minimal spinal cord diameter on MRI. C₅ nerve root palsy occurred in 7 cases (8.75%) in group A, including 4 cases of upper limb pain, 3 cases of upper limb pain, and 2 cases of residual upper limb pain and sensory loss at the last follow-up. C₅ nerve root palsy occurred in 5 cases (7.5%) in group B, 3 cases of upper limb pain, 2 cases of upper limb sensory loss, and all patients recovered normal radiation pain and sensory loss at the last follow-up. There was no significant difference in the incidence of C₅ nerve root palsy between the two groups. C₅ nerve root palsy, deltoid muscle, accompanied by neurological symptoms, recovery time were(2.3±1.0) N, 30 cases (37.5%), (11.4±1.0) weeks in group A, (2.8±0.8) N, 23 cases (28.8%), (8.2±0.8) weeks in group B, there was no significant difference on deltoid muscle decreased between the two groups, accompanied by neurological symptoms and the recovery time in group A was worse than the group B. Comparison of the two kinds of operation, the probability of postoperative C₅ nerve root palsy was equal, but the C₅ nerve root palsy in patients with C₄-C₆ open-door laminoplasty showed lighter symptom and faster recovery.

Cervical single open door laminoplasty with lateral mass screw fixation for the treatment of cervical spondylotic myelopathy with cervical instability

To evaluate the outcomes of single open door laminoplasty with lateral mass screw fixation in treating cervical spondylotic myelopathy (CSM) with cervical instability. From March 2010 to October 2012, 25 patients with spondylotic myelopathy and cervical instability underwent single open door laminoplasty with lateral mass screw fixation. There were 18 males and 7 females, aged from 57 to 68 years with the mean of 57 years. Japanese Orthopaedic Association (JOA) scores were used to evaluate clinical effects before operation and final follow up. Radiographical measures were made in change of Cobb angle by sagittal plane from C₂ to C₇, and cervical range of motion. All the patients were followed up from 18 to 36 months with an average of 25.6 months. Cerebrospinal fluid leakage occurred in 1 case, incision fat necrosis in 1 case, C₅ nerve root palsy in 4 cases. JOA scores was improved from preoperative 5.2±2.1 to 11.3±2.4 final follow up. Cobb angle was changed from preoperative (6.5±3.4)° to (13.2±4.9)° final follow up. Cervical range of motion was changed from preoperative (30.4±9.2)° to (26.5±8.4)° final follow up. As an effective treatment to CSM with cervical instability, single open door laminoplasty with lateral mass screw fixation has the advantage of extensive application scope, safety and steady, but the incidence rate of complication must be reduced.