Quan Gong

Hypoxia differentially regulates human nucleus pulposus and annulus fibrosus cell extracellular matrix production in 3D scaffolds

OBJECTIVE We hypothesize that intervertebral disc (IVD) cells from distinct region respond differently to oxygen environment, and that IVD cells from patients with disc degeneration can benefit from hypoxia condition. Therefore, we aimed to determine the transcriptional response and extracellular matrix (ECM) production of nucleus pulposus (NP) and annulus fibrosus (AF) cells to different oxygen tension. METHOD Human NP and AF from degenerated IVD were seeded in 3D scaffolds and subjected to varying oxygen tension (2% and 20%) for 3 weeks. Changes in ECM were evaluated using quantitative real-time reverse transcriptase polymerase chain reaction, histological and immunohistological analyses. RESULTS Hypoxia significantly enhances NP cells phenotype, which resulted in greater production of sulfated glycosaminoglycan (GAG) and collagen type II within the constructs and the cells expressed higher levels of genes encoding NP ECM. A significantly stronger fluorescent signal for hypoxia-inducible factor (HIF-1α) as also found in the NP cells under the hypoxic than normoxic condition. However, there was little effect of hypoxia on the AF cells. CONCLUSIONS The NP and AF cells respond differently to hypoxia condition on the 3D scaffold, and hypoxia could enhance NP phenotype. When used in concert with appropriate scaffold material, human NP cells from degenerated disc could be regenerated for tissue engineering application.

Effect of the Decompressive Extent on the Magnitude of the Spinal Cord Shift after Expansive Open-door Laminoplasty

Study Design. A retrospective study to analyze the effect of decompressive extent on the posterior shift of spinal cord after expansive open-door laminoplasty (ELAP). Objective. To investigate the effect of decompressive extent on cord shift distance after ELAP, and determine the morphologic limitations of posterior approach when the cervical alignment is lordotic or straight. Summary of Background Data. It is still controversial on the effect of space available for spinal cord at the level cephalad to the decompression with cord shift. Moreover, there is less understanding regarding the significance of decompressive extent of laminoplasty in relation to spinal cord shift and clinical outcome. Methods. Preoperative and postoperative MRIs of 76 patients with a straight or lordotic cervical spine who had undergone cervical laminoplasty were reviewed and evaluated retrospectively. Radiographic parameters including cervical sagittal alignment, space available at the level cephalad, the thickness of compressive mass, and the average anterior subarachnoid space were measured. Laminoplasty was performed from C1 to C7 in 11 cases (CI group), C2 to C7 in 30 cases (CII group), and C3 to C7 in 35 cases (CIII group). According to whether the anterior indirect decompression was adequate or not, CII and CIII groups were further divided into two subgroups, the noncontact group in which the spinal cord was completely separated from the anterior compressive mass after laminoplasty, and the contact group in which there was residual cord compression after laminoplasty. The recovery rate that based on the Japanese Orthopedic Association score was calculated for each patient. Results. There were statistically significant differences in the average anterior subarachnoid space among CI, CII, and CIII groups (P < 0.05);the average anterior subarachnoid space was the largest in CI group, and the smallest in CIII group. The space available at the level cephalad had strong sigmoidal correlation with cord postoperative shift in CIII group (R2 = 0.91). A higher neurologic recovery rate (69% ± 20% vs. 29% ± 11%; P < 0.05) in the noncontact group after surgery than in the contact group, with a similar follow-up period. Conclusion. The posterior decompression extent is a main factor affecting cord shift distance after laminoplasty in the context of a straightened or lordotic cervical curvature. The space available at the levels cephalad is a key factor to predict cord shift distance in laminoplasty from C3 to C7. Neurologic recovery rate after ELAP is affected by whether the anterior indirect decompression was adequate or not.

Clinical and radiography results of mini-plate fixation compared to suture suspensory fixation in cervical laminoplasty: A five-year follow-up study.

OBJECTIVES Lamina closure is the most common reason for failure of unilateral open-door laminoplasty. Mini-plate fixation was designed to solve such problem. We assessed the clinical outcomes and radiography results of mini-plate fixation by comparing it with suture suspension fixation. PATIENTS AND METHODS This prospective study enrolled 57 patients with multi-segment cervical spondylotic myelopathy between January 2008 and March 2010. Thirty-four patients underwent laminoplasty with mini-plate fixation (mini-plate group) whereas 23 patients underwent laminoplasty with suture suspension fixation (suture group). The neurological function was measured with the Japanese Orthopedic Association (JOA) score. Cervical range of motion (ROM), C2-7 angle, and the spinal canal expansive parameters (anteroposterior diameter, Pavlovs ratio, cross-sectional area, and open angles) were evaluated. RESULTS The mean follow-up time was 64 (60-82) months. There were no significant differences in preoperative JOA scores (p=0.191), postoperative JOA scores (p=0.700), preoperative cervical ROM (p=0.315) and preoperative C2-7 angle (p=0.074) between the two groups. Both groups had significant postoperative JOA improvement (p<0.05). The mini-plate group had larger cervical ROM (p=0.041) and C2-7 angle (p=0.040) than the suture group at the final follow-up. Both groups showed significant improvement in the spinal canal expansive parameters immediately after the surgery. In the suture group, the parameters, such as anteroposterior diameter, Pavlovs ratio, cross-sectional area, and open angles, decreased along with time, mainly within the first 6 months following the operation. In the mini-plate group, these parameters remained unchanged. The spinal canal expansive parameters between the 2 groups were not significantly different immediately following the operation, but were significantly different at the final follow-up (p<0.05). Three patients in the suture group displayed neurological deterioration due to lamina reclosure. CONCLUSIONS Laminoplasty by mini-plate fixation preserved more cervical ROM and better cervical alignment, maintained cervical spine canal expansive stability and effectively avoided lamina reclosure for a long-term follow-up.

One-stage Posterior Surgical Treatment for Lumbosacral Tuberculosis With Major Vertebral Body Loss and Kyphosis

The treatment goals of tuberculous spondylitis are to eradicate infection and to prevent or treat instability, deformity, and neurologic deficit. The purpose of this study was to evaluate the clinical outcomes following chemotherapy with 1-stage posterior debridement, correction, and instrumentation and fusion for the treatment of lumbosacral tuberculosis with major vertebral body loss and kyphosis. Fourteen patients with lumbosacral tuberculosis with major vertebral body loss and kyphosis underwent 1-stage posterior surgery. Clinical assessments included low back ache, Oswestry Disability Index, Scoliosis Research Society-22 scores, neurologic deficit, erythrocyte sedimentation rate, and C-reactive protein level. Radiographic parameters included kyphosis angle, anteroposterior translation, local scoliosis, lumbar lordosis, pelvic parameters, sagittal offset, and fusion. Thorough debridement was performed. Patients were followed for an average of 39.3 months. Constitutional symptoms, low back ache, and functional outcome improved in all patients postoperatively. At final follow-up, Frankel Grade improved by 0 to 2 grades, mean kyphosis angle improvement was 44.3°, and satisfactory spinopelvic and sagittal balance were achieved. Spinal posterolateral fusion was obtained in all patients and no fixation loosening was found at 2-year follow-up. Differences existed between the pre- and postoperative radiographic parameters (P<.05). Correction loss at last follow-up was not statistically significant (P>.05). No surgical complications or infection recurrence occurred. Tuberculosis can be cured and effective correction of kyphosis can be achieved for lumbosacral tuberculosis with major vertebral body loss and kyphosis by performing 1-stage posterior surgery and chemotherapy.

Anterior decompression and nonstructural bone grafting and posterior fixation for cervical facet dislocation with traumatic disc herniation.

Study Design. A series study of patients with lower cervical facet dislocation accompanied by traumatic disc herniation treated with anterior decompression and nonstructural bone grafting and posterior fixation. Objective. To describe a surgical technique of anterior decompression and nonstructural bone grafting and posterior fixation and its clinical outcome in a group of patients with lower cervical facet dislocation accompanied by traumatic disc herniation. Summary of Background Data. The optimal treatment for lower cervical facet dislocation with a prolapsed disc is still controversial. Methods. After discectomy and endplate preparation, a layer of morselized cancellous bone grafts from the iliac crest was placed in the interspace, and held in appropriate sagittal position by 2 layers of gelatin sponge and carefully sutured longus colli muscle. The anterior wound was then closed. The posterior elements were exposed and the reduction was performed. Fluoroscopy was used during reduction maneuver to ensure that the graft was still in the appropriate position. A posterior fusion was performed and the posterior wound was closed. Results. Between January 2006 and February 2010, 21 patients with cervical facet dislocation accompanied by traumatic disc herniation (13 unilateral dislocations and 8 bilateral dislocations) were recruited for this study. All the patients completed at least 1-year follow-up. Average follow-up duration was 29 ± 3.5 months. Average Frankel scales were significantly improved at the end of follow-up, visual analogue scale decreased from 7.8 ± 1.2 before the operation to less than 1.6 ± 0.5 (P < 0.05) 6 months later. Kyposis was corrected from 17.7° ± 6.3° to 6.5° ± 4.1° (P < 0.05) and remained at 5.9° ± 4.2° (P > 0.05) 1 year later. The average subsidence of bone graft was 1.28 ± 0.16 mm at 12 months after the operation and remained 1.34 ± 0.20 mm at 36 months after the operation. All patients had consolidation of both anterior and posterior fusions. No cases of instrument failure occurred and no complications were attributed to the use of this technique. Conclusion. Although further study based on injury types as well as long-term follow-up is still needed, anterior decompression and nonstructural bone grafting and posterior fixation provides a promising surgical option for treating cervical facet dislocation with traumatic disc herniation.

Multivariate Analysis of Factors Associated With Axial Symptoms in Unilateral Expansive Open-Door Cervical Laminoplasty With Miniplate Fixation.

AbstractRetrospective case–control study.Unilateral expansive open-door cervical laminoplasty with miniplate fixation is an efficient and increasing popular surgery for multilevel cervical spondylotic myelopathy. Axial symptoms are the most frequent complaints after cervical laminoplasty. But the mechanisms have not been fully clarified yet.The objective of this study is to compare the clinical and radiologic data between patients with or without axial symptoms and to investigate the factors associated with axial symptoms by multivariate analysis in cervical laminoplasty with miniplate fixation.A total of 129 patients who underwent cervical laminoplasty with miniplate fixation were comprised from August 2009 to March 2014. Patients were grouped according to whether they suffered from postoperative axial symptoms (PA) or not (NA). The clinical data including gender, age, duration of symptoms, diagnosis type, medical comorbidity, operative level, blood loss, operative time, pre- and post-Japanese Orthopedic Association (JOA) score, JOA recovery rates, and other complications were recorded. The radiologic data including cervical canal diameter, C2–7 Cobb angle, cervical range of motion (ROM), cross-sectional area, open angle, hinge union, and facet joint destroyed would be measured according to X-ray plain and CT scan images. The univariate analysis and multivariate logistic regression analysis were performed.There were 39 patients in PA group and 90 patients in NA group. Both groups gained significant JOA improvement postoperatively (P < 0.05). The preoperative neck pain (P = 0.048), negative change of cervical ROM (P = 0.018), and facet joints destroyed (P = 0.022) were significant different between the 2 groups. There were no significant differences for other clinical and radiography parameters between the groups (P > 0.05). The multivariate analysis showed that the negative change of cervical ROM (OR = 1.062, P = 0.047) and facet joints destroyed (OR = 0.661, P = 0.024) were related to axial symptoms.The change of cervical ROM and facet joints destroyed by miniscrews might be associated with axial symptoms after cervical laminoplasty with miniplate fixation. Cervical spine surgeons should carefully operate to decrease the injury of posterior musculature structure and protect the facet joints.

Anterior single segmental decompression and fixation for Denis B type thoracolumbar burst fracture with neurological deficiency: thirty-four cases with average twenty-six month follow-up.

Study Design. A series study of neurologically deficient patients with Denis B type thoracolumbar burst fractures treated with anterior single segmental decompression and fixation (ASSDF). Objective. To describe a surgical technique of ASSDF and its clinical outcome in a group of neurologically deficient patients with Denis B type thoracolumbar burst fractures. Summary of Background Data. The optimal treatment for thoracolumbar burst fractures is still controversial. Methods. The canals of selected patients were fully decompressed with partial dissection on fractured vertebral body. Single segmental fusion was achieved with grafting and fixation. Clinical evaluation (including Frankel scales and visual analogue scale) and radiologic assessments (including the measurements of the kyphosis Cobb angle, adjacent superior, inferior intervertebral disc height, and vertebral canal sagittal diameter on radiograph film and computer tomography scans) were performed before the operation and at 3-day, 6-month, 1-, 2-, and 3-year intervals after the operation. Results. Between June 2006 and May 2008, 37 patients with Denis B type thoracolumbar burst fractures were recruited for study. Thirty-four patients with successful ASSDF accomplished a 1-year follow-up. Average follow-up duration was 26 ± 9.2 months. The average operation time and blood loss were 173 ± 26 minutes and 445.6 ± 164.4 mL, respectively. Average Frankel scales were significantly improved at the end of follow-up. visual analogue scale decreased from 7.2 ± 0.8 before operation to less than 1.7 ± 0.7 (P < 0.05) 6 months later. The vertebral canal sagittal diameter was enlarged from an average of 5.9 ± 1.2 mm to 16.2 ± 1.0 mm (P < 0.01). The canal stenosis index also improved, from 36.0% to 99.1%. Kyphosis was corrected from 21.5° ± 6.1° to 7.3° ± 3.2° (P < 0.05) and remained at 8.2° ± 3.6° (P > 0.05) 1 year later. Adjacent disc heights remained constant. No serious complications or fixation failures were observed during follow-up. Conclusion. ASSDF provides a novel and effective surgical option for treating Denis B type fracture with neurologic deficiency.

Effect of Mini-plate Fixation on Hinge Fracture and Bony Fusion in Unilateral Open-door Cervical Expansive Laminoplasty.

Study Design:This was a retrospective study. Objective:The aim of this study was to investigate the effect of Centerpiece mini-plate fixation on the complete fracture and bony fusion of the hinge side in unilateral open-door cervical expansive laminoplasty. Summary of Background Data:Cervical laminoplasty is an effective and safe surgery for cervical canal stenosis. The Centerpiece mini-plate is an instrument used to secure the laminae and maintain the cervical canal expansion. Stability of the new laminae is largely dependent on healing of the hinge side bone fracture and the degree of bony fusion. To date, few studies have reported on the effects of mini-plate fixation on these 2 important factors. Materials and Methods:Between September 2009 and March 2011, 58 patients received unilateral open-door cervical expansive laminoplasty at the authors’ hospital. The group included 47 male and 11 female patients, with a mean age of 61 (range, 35–81) years. Two hundred twenty-five laminae were fixed using the Centerpiece mini-plate (group A), whereas 62 laminae were fixed using suture suspension (group B). The rates of fracture and bony fusion of the hinge were observed using computed tomography scan and compared between the 2 groups. The complete fractures were subdivided into 4 groups based on the degree of displacement of the fractured ends: type I (no displacement), type II (mild to moderate displacement), type III (complete displacement or separation), or type IV (the hinge had collapsed into the cervical canal). Results:The number of incomplete fractures and type I to IV fractures in group A were 95, 93, 25, 8, and 4 and 29, 25, 4, 2, 2 in group B, respectively. There were no significant differences between the 2 groups in terms of complete fracture rates (P=0.309) and complete fracture type distribution (P=0.694). Group A had a significantly higher rate of bony fusion of the hinge 3 months after surgery (82% vs. 70%, P=0.042); however, this rate was not statistically significant 6 months after surgery (P=0.141). For type I complete hinge fracture, group A had higher bony fusion rates, both 3 months (86% vs. 57%, P=0.004) and 6 months (92% vs. 85%, P=0.048) postoperatively. The rates of bony fusion were also significantly different among all complete fracture types 3 months (P<0.001) and 6 months (P<0.001) postoperatively. Conclusions:Centerpiece mini-plate fixation in unilateral open-door cervical expansive laminoplasty might not increase the complete fracture rate compared with suture suspension and might promote bony fusion of type I complete hinge fractures.

The effect of deviated center of rotation on flexion-extension range of motion after single-level cervical arthroplasty: an in vivo study.

Study Design. A retrospective study. Objective. To report the clinical outcomes and sagittal kinematics after cervical total disc replacement (TDR). To evaluate the in vivo effect of deviated center of rotation (COR) on flexion-extension range of motion (ROM) at the instrumented level. Summary of Background Data. A few studies showed that the location of COR after cervical TDR deviated from its preoperative location or inherent location in healthy subjects. However, little is known about the effect of deviated COR on ROM at the instrumented level. Methods. A total of 24 patients who underwent C5–C6 single-level TDR with Prestige LP (Medtronic Sofamor Danek) were retrospectively included. Japanese Orthopedic Association score and visual analogue scale were used to assess the clinical outcomes. ROM and COR were measured for radiographical analysis. Patients were categorized into 2 groups according to the change of ROM for further evaluation. Group 1, characterized by decreased postoperative ROM, consisted of 16 patients; group 2, characterized by increased postoperative ROM, consisted of 8 patients. Results. Ten males and 14 females comprised the study cohort. The mean age was 45.05 years, and the mean follow-up time was 15.5 months. The Japanese Orthopedic Association score increased significantly and the neck and arm visual analogue scale decreased significantly after cervical TDR. On average, ROM was preserved after cervical TDR. The postoperative COR had a significant cranial shift from its preoperative location. The COR shift in anterior-posterior direction was larger in group 2 than that in group 1. No difference was observed in the COR shift in cranial-caudal direction between the 2 groups. Conclusion. Single-level cervical TDR with Prestige LP obtained satisfactory clinical outcomes and partially restored the natural cervical kinematics. At instrumented level, the deviated COR had a negative correlation with the flexion-extension ROM. Level of Evidence: 3

Causes, treatment and prevention of esophageal fistulas in anterior cervical spine surgery.

To evaluate the causes, treatment and prevention of esophageal fistulas after anterior cervical spine surgery.