Laminectomy with Rib Shears: A Technical Note.

Introduction: Laminectomy/laminoplasty either free or vascularized pedicle flap is currently performed with a variety of expensive instruments. Use of Tudor Edwards rib shears to perform above procedure is described. Materials and Methods: Tudor Edwards rib shear was used to cut lamina in 18 cases for a variety of spinal lesions. Depending upon the size of lesion, laminectomy/laminoplasty was required for 2 to 8 levels. Vascularized pedicle laminoplasty or free flap laminoplasty was done with Tudor Edwards rib shears. Ligamentum flavum and interspinous and supraspinous ligaments were preserved in cases of vascularized pedicled laminoplasty, which was carried out in 12 cases. Free flap laminoplasty was carried out in 6 cases. Results: In all our cases, laminectomy was successfully achieved with rib shears without any injury to the dura or its underlying structures. It was possible to perform vascularized pedicle laminoplasty or free flap laminoplasty in all cases. Laminectomy was easier to perform in the cervical region and dorsal region, while it was difficult in the lumbar region due to the wider, thick lamina and its angulation, especially in adults. Conclusion: Laminectomy/laminoplasty with Tudor Edwards rib shears is quick, safe, and easy. Beveled cut edges with minimal bony loss prevents sinking of laminoplasty, thereby facilitates lamina fixation. This is an alternative method of performing laminectomy/laminoplasty, especially for those not having accessibility to expensive equipment.

Correlation Analysis for Selection of Microtitanium Plates with Different Specifications for Use in a Cervical Vertebral Dome Expansion Laminoplasty.

OBJECTIVE: To analyze correlations between the selection of microtitanium plates with different specifications for use in a cervical vertebral dome expansion laminoplasty. METHODS: Sixteen patients that underwent the cervical vertebral dome expansion laminoplasty with a cervical spinal stenosis angioplasty procedure for treatment of their cervical spinal cords were recruited at our hospital. From February 2017 to September 2018, medical records confirmed that all patients underwent cervical CT and MRI tests pre- and postsurgery. The anteroposterior diameter of the spinal canal, changes in the cross-sectional area of the spinal canal, and the pre- and postsurgery distance of the cervical spinal cord after applying microtitanium plates with different lengths were measured by Mimics version 17.0 software (Materialise NV, Leuven, Belgium). A statistical regression and correlation analysis of relevant specification parameters of the microtitanium plate was then studied. RESULTS: As the size of the microtitanium plate increased, we found that the cross-sectional area of cervical spinal canal and distance between the descendants of the lamina and the distance of cervical spinal cord concordantly increased, and these data changes linearly. The regression equation associated with sagittal diameter, cross-sectional area, and posterior movement distance of the cervical spinal cord was obtained. CONCLUSION: According to the correlation analysis of imaging data changes, the regression equation was obtained to guide the selection of microtitanium plates with appropriate specifications in a cervical vertebral dome expansion laminoplasty.

Open-Door Laminoplasty Using Lateral Mass Anchoring Screws and Nonabsorbable Sutures in Patients with Multilevel Cervical Myelopathy.

BACKGROUD: The purpose of this study was to evaluate the clinical usefulness of open-door laminoplasty using lateral mass anchoring screws and nonabsorbable sutures (ODLLM) for multilevel cervical myelopathy. METHODS: We retrospectively studied 30 patients who underwent ODLLM. Clinical evaluations were performed using a visual analog scale (VAS), Japanese Orthopaedic Association (JOA) score, and Neck Disability Index (NDI) preoperatively, at 1 year postoperatively, and at the last follow-up. Radiographic evaluation was done using cervical spine radiographs to measure changes in the lordotic angle and range of motion (ROM) preoperatively, at 1 year postoperatively, and at the last follow-up and computed tomography at 1 year postoperatively to measure the opening angle and anteroposterior diameter of the spinal canal. RESULTS: Significant improvement in VAS, JOA, and NDI was seen overall at 1 year after operation. However, there was no significant difference between 1 year after operation and the last follow-up. There were no significant changes in the lordotic angle and neck ROM. The mean opening angle of the opened lamina was measured as 39.04°. The mean anteroposterior diameter was significantly increased from 7.51 ± 1.79 mm before surgery to 13.98 ± 1.80 mm at 1 year of operation. Complications such as laminar reclosure and screw loosening were not observed in all cases. CONCLUSIONS: The ODLLM was technically easy to perform and showed good results comparable to those of conventional techniques. It can be suggested that ODLLM is an appropriate treatment option for multilevel cervical myelopathy.

Application of Laminoplasty Combined with ARCH Plate in the Treatment of Lumbar Intraspinal Tumors.

OBJECTIVE: To investigate the bone fusion and clinical effect of laminoplasty combined with ARCH plate fixation in the treatment of lumbar intraspinal tumors. METHODS: This was a clinical study. From June 2017 to January 2019, 24 patients (seven males and 17 females, average age 40 ± 16 years) with lumbar intraspinal tumors underwent laminoplasty combined with ARCH plate fixation in our hospital. The bone fusion was evaluated by X-ray and computed tomography (CT) scans that were taken 15.2 ± 2.17 months postoperatively. Each segment showed a bone bridge on one side, which was classified as "segmental partial fusion." Each segment showed bilateral bone bridges, which were classified as "segmental complete fusion". When all segments of the patient showed bilateral bone bridging so that the replanted lamina and the host lamina became a unit on the CT scan, it was defined as "complete fusion". In addition, the operation time and blood loss were recorded. Fisher's exact test was used to analyze the potential influencing factors of bone healing, including age (≤40 years vs >40 years), gender, number of operated levels (single vs two). Paired t-test was used to analyze pre- and postoperative Oswestry Disability Index (ODI) scale and low back and leg pain visual analog scale (VAS). RESULTS: A total of 33 segments of laminoplasty were successfully performed in 24 patients. The average operation time was 128 ± 18 minutes. The average blood loss was 110 ± 19 mL. All patients were followed up at least 12 months after operation (average, 15.2 ± 2.17 months). At the final follow-up, according to the definition of this study, the proportion of "segmental partial fusion" and "segmental complete fusion" were 30.3% (10/33) and 69.7% (23/33), respectively. And the proportion of patients with "complete fusion" was 70.8% (17/24). Age, gender, and number of operated levels were not associated with the fusion (P = 1.0, 0.37, and 0.06, respectively). ODI and VAS were much better at 1 month after operation and the final follow-up than those before the operation (P < 0.01). At 6 months after operation, the results of magnetic resonance imaging (MRI) showed that the supraspinous ligament was repaired, and there were no complications, such as spinal epidural scar recompression. CONCLUSIONS: Laminoplasty combined with ARCH plate was a better surgical method, and 70.8% of the patients showed complete bone fusion and there was no case of bilateral nonunion.

Clinical outcome and radiological findings after cervical open door laminoplasty with titanium basket.

OBJECT: Cervical laminoplasty, which is well described in the Japanese literature, is the gold standard for decompressing multilevel spinal cord compression. Several spacers have been introduced to provide enough decompression of the spinal canal and reconstruct the stable posterior elements. The purpose of this study was to retrospectively evaluate radiological outcomes after open door laminoplasty using the titanium spacer (Laminoplasty Basket: L-Basket; Ammtec, Tokyo). METHODS: Between July 2014 and June 2016, 31 patients with cervical spondylotic disease, including OPLL, were underwent open door laminoplasty with this device. All patients were clinically assessed by JOA score. The average follow-up period was 48.9 months with a range of 37-60 months. Postoperative radiological evaluation revealed bone union on both the open side and the gutter side from 12 months to 36 months after surgery on computed tomography. RESULTS: The clinical outcome improved from 10.9 points on the Japanese Orthopaedic Association scale to 15.8 points at 3 months after surgery and there were no significant major complications such as the implant failure. The bone union rate of the gutter side was 85.9% (85/99) at 1 year, 96.0% (95/99) at 3 years after surgery and of the open side was 57.6% (57/99) at 1 year, 89.9% (89/99) at 3 years after surgery. Circumferential fusion was confirmed 85.9% (85/99) of the time. CONCLUSION: This titanium spacer seemed to have the potential of promoting bone union between the spacer and both lamina, and lateral mass in cervical laminoplasty which is a safe procedure with satisfactory clinical results.

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.

Comparison of microendoscopic selective laminectomy versus conventional laminoplasty in patients with degenerative cervcical myelopathy: a minimum 2-year follow-up study.

BACKGROUND: Although microendoscopic partial laminectomy for patients with degenerative cervical myelopathy (DCM) has been reported and demonstrated good results, a detailed comparison of its mid-term surgical results with those of laminoplasty (LP) has not been reported. The aim of this study was to compare the surgical outcomes, complications, and imaging parameters of cervical microendoscopic interlaminar decompression (CMID) via a midline approach versus conventional laminoplasty, with a minimum follow-up period of 2 years. METHODS: Two hundred and fifty-four patients who underwent either LP or CMID for DCM between May 2008 and April 2015 were enrolled. All patients routinely underwent LP (C3-6 or C3-7) before December 2011, whereas CMID was performed at the one or two affected level(s) only in patients with single- or two-level spinal cord compression after 2012. Surgical procedure (CMID): For single-level patients (e.g., C5-6), partial laminectomy of C5 and C6 was performed under a microendoscope. For two-level patients (e.g., C5-6-7), decompression was completed by performing a C6 laminectomy. We compared surgical outcomes and radiographic parameters between the CMID and LP groups. RESULTS: Of the 232 patients followed up for > 2 years, 87 patients with single- or two-level spinal cord compression, 46 that underwent CMID, and 41 that underwent LP were identified. There were no differences in the baseline demographic data of the patients between the groups. CMID showed better outcomes in terms of postoperative axial pain and quality of life, although both procedures showed good neurological improvement. Two and one patient complained of C5 palsy and hematoma, respectively, only in the LP group. The postoperative range of motion was worse and the degree of postoperative posterior spinal cord shift was larger in the LP group. CONCLUSION: Selective decompression by CMID demonstrated surgical outcomes equivalent to those of conventional LP, which raises a question regarding the requirement of extensive posterior spinal cord shift in such patients. Although the indications of CMID are limited and comparison with anterior surgery is mandatory, it can be a minimally invasive procedure for DCM. .

Short-term Outcomes Following Cervical Laminoplasty and Decompression and Fusion With Instrumentation.

STUDY DESIGN: Retrospective review of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database years 2010 to 2015. OBJECTIVE: Investigate which short-term outcomes differ for cervical laminoplasty and laminectomy and fusion surgeries. SUMMARY OF BACKGROUND DATA: Conflicting reports exist in spine literature regarding short-term outcomes following cervical laminoplasty and posterior laminectomy and fusion. The objective of this study was to compare the 30-day outcomes for these two treatment groups for multilevel cervical pathology. METHODS: Patients who underwent cervical laminoplasty or posterior laminectomy and fusion were identified in National Surgical Quality Improvement Program (NSQIP) based on Current Procedural Terminology (CPT) code: laminoplasty 63,050 and 63,051, posterior cervical laminectomy 63,015 and 63,045, and instrumentation 22,842. Propensity-adjusted multivariate regressions assessed differences in postoperative length of stay, adverse events, discharge disposition, and readmission. RESULTS: Three thousand seven hundred ninety-six patients were included: 2397 (63%) underwent cervical laminectomy and fusion and 1399 (37%) underwent cervical laminoplasty. Both groups were similar in age, sex, body mass index (BMI), American Society of Anesthesiologist Classification (ASA), Charleston Comorbidity Index (CCI), and had similar rates of malnutrition, chronic kidney disease, diabetes, chronic obstructive pulmonary disease, and history for steroid use. Age more than 70 and age less than 50 were not associated with one treatment group over the other (P > 0.05). Compared with laminoplasty patients, laminectomy and fusion patients had increased lengths of stay (LOS) (4.5 vs. 3.7 d, P < 0.01) and increased rates of adverse events (41.7% vs. 35.9%, P < 0.01), discharge to rehab (16.4% vs. 8.6%, P < 0.01), and skilled nursing facilities (12.2% vs. 9.7%, P = 0.02), and readmission (6.2% vs. 4.5%, P = 0.05). Both groups experienced similar rates of death, pulmonary embolus, deep vein thrombosis, deep and superficial surgical site infection, and reoperation (P > 0.05 for all). CONCLUSION: Posterior cervical laminectomy and fusion patients were found to have increased LOS, readmissions, and complications despite having similar pre-op demographics and comorbidities. Patients and surgeons should consider these risks when considering surgical treatment for cervical pathology. LEVEL OF EVIDENCE: 3.

Bone bonding, displacement, and absorption in cases of double-door laminoplasty with unidirectional porous hydroxyapatite spacers.

We used a newly developed, high-porosity unidirectional porous hydroxyapatite spacer (Regenos spacer, not approved by the FDA). To assess the short-term bone bonding capacity of Regenos spacer used in a double-door laminoplasty, including displacement, deformation, and absorption after implantation. Fifty patients underwent a double-door laminoplasty using Regenos spacers, with computed tomography (CT) images obtained at 2-4 weeks and 6-12 months, post-surgery, in 30 patients. Bone bonding rate, amount of displacement, and the incidence of deformation and absorption were evaluated from the early and late postoperative CT images. Bone bonding rate for Regenos spacers, using our modified classification, was 48.9% at 6 months, post- surgery, and 67.0% at 12 months. The change in anterior-posterior diameter of the spinal canal (ΔH) was significantly greater for Regenos spacers than for autologous bone spacers (p < 0.05). There was no difference in the change in angle between the vertebral arch and the posterior wall of the vertebral body (ΔR) between the Regenos and autologous bone spacers. Deformation was identified in 21.3% (10/47). Though, no evidence of breakage along their long axis was identified among these 10 cases on axial CT images with passable clinical results. Regenos spacers lowered the risk of early dislocation after implantation and facilitated bone bonding due to infiltration of surrounding tissue. However, the deformation and absorption was observed at high rates because of their insufficient mechanical strength, we need to require a longer term follow-up to more clearly evaluate their adverse impact in clinically.

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

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.

Management of late-onset deep surgical site infection after instrumented spinal surgery.

BACKGROUND: There are no universally accepted protocols for the treatment of late-onset deep surgical site infection. This study retrospectively evaluates the methods of aggressive debridement with instrumentation retention, high vacuum closed-suction drain without irrigation, primary wound closure, and antibiotic therapy for the treatment of late-onset deep surgical site infection after instrumented spinal surgery. METHODS: A total of 4057 patients who underwent instrumented spinal surgeries were surveyed from January 2010 to June 2014. Surgical debridement was performed immediately after late-onset deep surgical site infection was identified. In addition to extended resection of the devitalized and necrotic tissue, the biofilms adhered to the surface of implants were removed meticulously and thoroughly. Primary wound closure was performed on each patient, and closed suction drains were maintained for about 7-10 days without irrigation. Antibiotic therapy was administered for 3 months according to the results of the pathogenic culture. RESULTS: Forty-two patients were identified as having late-onset deep surgical site infection. Staphylococcus aureus was the most common pathogen in this group. Seven patients with late-onset deep surgical site infection had negative bacterial culture results. Infections resolved in all patients. Forty-one patients retained their instrumentation, whereas 1 patient had the implants removed because of Staphylococcus aureus infection, which was found the implants loosening during debridement. Primary wound healing was found in all patients with no recurrence of infection during the follow-up periods. CONCLUSIONS: A timely diagnosis, aggressive and meticulous debridement, high vacuum closed-suction drain, routine and adequate use of antibacterial agents are the keys to successfully resolving infection and keeping implants retention in the treatment of late-onset deep surgical site infection after instrumented spinal surgery.

Comparison of anchor screw fixation versus mini-plate fixation in unilateral expansive open-door laminoplasty for the treatment of multi-level cervical spondylotic myelopathy.

STUDY DESIGN: Systematic review and meta-analysis. BACKGROUND: Anchor screw fixation and mini-plate fixation are widely used in unilateral open-door laminoplasty. There is a great controversy over the preferred fixation method. The purpose of this study is to evaluate the clinical outcomes between anchor screw fixation and mini-plate fixation for the treatment of multilevel cervical spondylotic myelopathy (MCSM). METHODS: Related studies that compared the clinical effectiveness of anchor screw fixation and mini-plate fixation in cervical laminoplasty for the treatment of MCSM were acquired by a comprehensive search in PubMed, Embase, the Cochrane library, CNKI, VIP, and WANFANG up to March, 2018. Included studies were evaluated according to eligibility criteria. The main end points included: preoperative Japanese Orthopedic Association (JOA) scores, postoperative JOA scores, JOA scores improvement rate, preoperative and postoperative cervical range of motion (ROM), preoperative and postoperative cervical curvature index (CCI), lamina open angle, operation time, blood loss, C5 nerve palsy rate and axial symptoms rate. RESULTS: Papers in English and Chinese were searched for the initial review, but only 12 articles in Chinese were included in this meta-analysis. All of the selected studies were of high quality as indicated by the Newcastle-Ottawa scale (NOS). Among 809 patients, 372 underwent anchor screw fixation and 437 underwent mini-plate fixation. The results of this meta-analysis indicated that no significant difference was found in preoperative JOA score, JOA scores improvement rate, preoperative CCI, preoperative ROM, C5 palsy rate and blood loss. However, compared with mini-plate fixation, anchor screw fixation patients showed higher axial symptoms rate [RR = 1.75, 95% CI (1.31, 2.35), P <.05], lower postoperative JOA scores [SMD = -0.38, 95% CI (-0.62, -0.15), P <.05], lower postoperative CCI [SMD = -0.64, 95% CI (-0.94, -0.33), P <.05], lower postoperative ROM [SMD = -1.11, 95% CI (-2.18, -0.04), P <.05], smaller lamina open angle [SMD = -1.98, 95% CI (-3.71, -0.24), P <.05], shorter operation time [SMD = -0.33, 95% CI (-0.59, -0.07), P <.05]. CONCLUSIONS: Compared with anchor screw fixation, mini-plate fixation in cervical laminoplasty appears to achieve better clinical and radiographic outcomes with fewer surgical complications. However, future well-designed, randomized controlled trials are still needed to further confirm our results.

In vitro biomechanical evaluation of a monocoque plate-spacer construct for cervical open-door laminoplasty.

PURPOSE: To evaluate biomechanical differences between two surgical procedures for cervical open-door laminoplasty using human cadaveric spines. METHODS: Twenty-four cervical vertebrae (C4-C6) from eight fresh-frozen human cervical spines were subjected to mechanical testing after being instrumented for open-door laminoplasty using a newly designed plate-spacer device with a monocoque structure (plate-spacer group; n = 12) or by conventional miniplate-alone fixation (miniplate group; n = 12). Cantilever bending testing was performed by applying a compressive load in the cranio-caudal direction to the base of the spinous process of the reconstructed laminar arch constructs until failure and strength and stiffness of the laminar arch were determined. The results are presented as mean ± standard deviation. RESULTS: The plate-spacer group was approximately twice as strong as the miniplate group (27.6 ± 16.5 N vs. 13.5 ± 7.3 N, p < 0.05). Stiffness in the plate-spacer group exhibited the same trend (19.6 ± 9.3 N/mm vs. miniplate group: 11.4 ± 6.9 N/mm, p < 0.05). CONCLUSION: The fixation with the monocoque plate-spacer construct for open-door laminoplasty provided higher structural properties when compared against the plate-alone fixation. The spacer in the plate-spacer construct appears to contribute by preventing large deformations of the laminar arch caused by bending in cranio-caudal direction. Future studies will be required to investigate stress/strain distribution in the laminar arch constructs.

Regenos spacers are not suitable for open-door laminoplasty because of serious adverse events caused by their insufficient mechanical strength.

We used a newly developed, high-porosity unidirectional porous hydroxyapatite spacer (Regenos spacer, not approved by the FDA). The aim of the present study was to elucidate the effectiveness of Regenos laminar spacers for open-door type laminoplasty. The present study included 39 patients who underwent open-door type laminoplasty with Regenos spacers from April 2015 to December 2016 and were followed up for at least 6 months after surgery. We grafted 68 Regenos spacers in 39 patients. Pre- and postoperative neurological status of patients were evaluated using JOA score and recovery rate. Breakage of Regenos spacers, laminar closure, and bone-hydroxyapatite spacer bonding were assessed using 12-month postoperative sagittal and axial CT images. The average preoperative JOA score was 9.5 ±â€¯3.2/17, and the average postoperative JOA score was 12.5 ±â€¯2.9/17. JOA score recovery rate was 34 ±â€¯41% at the latest follow-up visit. The bony fusion rate of the hinge sides was 87%. Breakage and deformity of implanted spacers was observed in 69% of patients and 59% of spacers with a CT sagittal view, and CT axial view at 12 months revealed fine cracks and collapse in 17 spacers in 14 patients. The average angle was -2.4 ±â€¯4.8°, including 46 of 68 spacers showing a negative value, resulting in a rate of laminar reclosure of 35%. Postoperative CT demonstrated good bone bonding rate. Nevertheless, clinical results with low recovery rates were obtained with complications related to the use of Regenos spacers.

Piezoelectric Surgery for Dorsal Spine.

BACKGROUND: Laminoplasty and laminectomy are 2 common surgical procedures used in treating degenerative and neoplastic diseases of the spinal canal. Routinely used instruments, such as the Kerrison rongeur and high-speed drill, can result in potentially serious complications, such as dural injury and thermal and mechanical damage to neurovascular structures. We adopted piezoelectric bone surgery, which permits a selective cut of mineralized tissues, to perform posterior procedures on the thoracic spine, where the relationship between bone and the spinal cord is critical. The aim of this article was to evaluate the use of piezoelectric surgery for performing dorsal spine laminectomy and laminoplasty. METHODS: The Mectron piezosurgery device was developed for cutting bone with microvibrations that are created by the piezoelectric effect. This instrument allows a safe and precise bone cut, and it is characterized by no heat generation, thus avoiding thermal injury to bone and soft tissues. We used this device to perform 8 laminoplasties for tumors of the dorsal spine and 2 laminectomies for thoracic spinal stenosis in 10 patients. RESULTS: There were no procedure-related intraoperative complications, such as dural injury or damage to neural structures. CONCLUSIONS: The piezoelectric device showed excellent results in terms of safety and precise bone cutting properties when performing posterior surgical procedures in the dorsal spine, where thermal injury produced by the conventionally used drill may damage the spinal cord closer to bony elements.

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: (Equation is included in full-text article.), 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.

Radiological analysis of minimal safe distance and optimal screw angle to avoid facet violation in open-door laminoplasty using precontoured plate.

PURPOSE: This study aimed to present radiologic analysis of minimal safe distance (MSD) and optimal screw angle (OSA) that enables to fix screws in a lateral mass safely without facet joint violation in open-door laminoplasty using a plate. METHODS: A retrospective analysis was made of 22 patients (male: 17; female: 5), average age 62 years. Seventy-nine lateral mass screws were fixed among a total of 158 screws. MSD that doesn't allow 5-mm screws to violate a facet joint was measured for C3-C7 and a comparative analysis was performed. If the MSD is not secured, the OSA to be given to the cephalad direction is calculated to avoid violation of the facet joint. RESULTS: The screws violating inferior facet joints accounted for 34.1% of the screws fixed in inferior lateral mass. Joint surface to distal mini-screw distances were 3.18 ± 1.46 mm and 4.75 ± 1.71 mm in groups of facet joint violation and non-facet violation (FV), respectively ( p = 0.001). When 5-mm screws were inserted into a lateral mass, MSD was 4.39 ± 0.83 mm. The average MSD of C3, C4, and C5 was 4.05 ± 0.78 mm, 4.10 ± 0.70 mm, and 4.26 ± 0.74 mm, respectively. There was no significant differences among levels ( p > 0.05). The average MSD of C6 and C7 was 4.92 ± 0.81 mm and 4.80 ± 0.96 mm, respectively, showing significant differences from those of C3, C4, and C5 ( p < 0.05). If 6 mm of the MSD isn't secured, OSA showed in the cephalad direction of 11.5° for 5 mm and 22° for 4 mm approximately. CONCLUSION: We suggest that mini-screw on lateral mass can be fixed safely without FV, if they are fixed at MSD of 6 mm from a joint surface. Facet joint violation doesn't occur if an OSA is given in the cephalad direction in case of not enough MSD for mini-screws.

Mini-plate fixation versus suture suspensory fixation in cervical laminoplasty: A meta-analysis.

BACKGROUND: Both the mini-plate fixation and suture suspensory fixation techniques are extensively applied in cervical laminoplasty, but which technique is superior has not been ascertained. The purpose of this meta-analysis is to compare the results between mini-plate fixation and suture suspensory fixation in cervical laminoplasty for the patients with multilevel cervical compressive myelopathy. METHODS: PubMed, Embase, the Cochrane library, CNKI, and WANFANG were searched for studies that compared mini-plate fixation and suture suspensory fixation in cervical laminoplasty up to November 1, 2016. We calculated odds ratio (OR) with 95% confidence interval (CI) for dichotomous outcomes and mean difference (MD) with 95% CI for continuous outcomes. Review Manager 5.3 was used for the statistical analyses. RESULTS: A total of 25 studies, involving 1603 participants, were included in this review. The results of this meta-analysis indicated that there were statistically significant differences in postoperative Japanese Orthopedic Association (JOA) scores (MD = 0.67, 95% CI: 0.34-0.99, P < 0.001), JOA scores improvement rate (MD = 4.00, 95% CI: 2.51-5.50, P < 0.001), postoperative Visual Analogue Score (VAS) (MD = -0.81, 95% CI: -1.36 to -0.26, P = 0.004), postoperative range of motion (ROM) (MD = 4.15, 95% CI: 2.06-6.23, P < 0.001), postoperative cervical lordosis (MD = 3.1, 95% CI: 2.02-4.18, P < 0.001), postoperative anteroposterior diameter of the spinal canal (MD = 1.53, 95% CI: 0.11-2.95, P = 0.03), postoperative open angle (MD = 1.93, 95% CI: 0.14-3.71, P = 0.03), postoperative cross-sectional area of the spinal canal (MD = 37.10, 95% CI: 26.92-47.29, P < 0.001), axial symptoms (OR = 0.28, 95% CI: 0.20-0.37, P < 0.001), operation time (MD = 4.46, 95% CI: 0.74-8.19, P = 0.02), and blood loss (MD = 9.24, 95% CI: 6.86-11.62, P < 0.001). However, there was no statistically significant difference in C5 palsy (OR = 0.82, 95% CI: 0.37-1.84, P = 0.63). CONCLUSIONS: As compared with suture suspensory fixation, mini-plate fixation in cervical laminoplasty appears to achieve better clinical and radiographic outcomes with fewer surgical complications. However, mini-plate fixation is associated with bigger surgical trauma. This conclusion should be interpreted cautiously and more high-quality, randomized controlled trials are needed in the future.

Clinical outcome and safety study of a newly developed instrumented French-door cervical laminoplasty technique.

BACKGROUND: Standard laminectomy for treatment of cervical myelopathy is associated with secondary instability and kyphosis, while laminectomy combined with fusion puts adjacent segments at risk of degeneration. Single- and double-door laminoplasty techniques have been developed to overcome these limitations. More recently, complications related to bone graft dislodgment have fostered development of hardware-augmented laminoplasty techniques. The aim of this study is to review the clinical safety and effectiveness of a newly developed technique of instrumented French-door laminoplasty for treatment of cervical myelopathy. MATERIALS AND METHODS: A series of 25 consecutive myelopathic patients were treated with a novel instrumented cervical French-door laminoplasty technique, whereby the enlarged posterior arch was held open with maxillofacial plates and screws. Patients had pre- and postoperative assessments with the Neck Disability Index (NDI), Japanese Orthopaedic Association (JOA) Score, Visual Analogue Score and radiographs. Minimum follow-up was 40 months, with regular interval assessments. RESULTS: There were 18 males with a mean age of 45 years. The mean operative time was 145 min. The average hospital stay was 2.4 days and the mean follow-up was 56.5 months (40-72). All patients reported neurological improvements and there was a 35% improvement in NDI, and JOA score improved by 4.8 points. No postoperative hardware-related complications were noted and only one case of temporary C5 palsy, which completely resolved by the one-year follow-up. CONCLUSIONS: Our data and clinical experience demonstrate that this hardware-augmented laminoplasty technique is safe and effective. We observed no hardware-related complications in our series. The use of readily available maxillofacial titanium miniplates and ease of surgical procedure means that this technique can be easily adopted into clinical practice. LEVEL OF EVIDENCE: Level IV.

Double-door cervical laminoplasty with suture anchors: evaluation of the clinical performance of the constructs.

PURPOSE: We aimed to investigate the clinical performance of the constructs of double-door cervical laminoplasty with suture anchors by examining bony fusion at the hinges and lamina closure. METHODS: We retrospectively analysed computed tomography (CT) scans obtained preoperatively, immediately after the operation, and at follow-up of patients who underwent cervical laminoplasty using suture anchors. Hinge fracture, bony healing at the hinges, suture anchor failure, and the lamina angle (LA) were evaluated using CT. Lamina closure was defined as an LA <55° at follow-up. RESULTS: A total of 226 laminae and hinges from 37 patients were evaluated. CT scans immediately after the operation revealed that 13 laminae (5.8 %) were fractured, one of which collapsed into the spinal canal. Bony fusion at an average of 12.7 months after the operation was noted at 222 hinges (98.2 %), which was not affected by hinge fracture. One dislodged suture anchor was identified. The mean LAs were 34.4 ± 4.2° preoperatively, 87.4 ± 12.3° immediately after the operation, and 82.5 ± 12.9° at follow-up. At follow-up, four cases of lamina closure were identified (1.8 %), and the closure rate was significantly higher at C3 than at the other levels, although it was not affected by age, sex, causative disease, cervical alignment, suture anchor use, and hinge fracture. CONCLUSIONS: The constructs of double-door cervical laminoplasty with suture anchors are stable with a high rate of fusion at the hinges. However, if the procedure is performed at C3, special modifications should be made to avoid lamina closure.