Yueming Song

Comparison of artificial total disc replacement versus fusion for lumbar degenerative disc disease: a meta-analysis of randomized controlled trials.

PurposeTo compare the efficacy and safety of TDR to that of the fusion for the treatment of lumbar degenerative disc disease (LDDD).MethodsRandomized controlled trials comparing TDR with any other intervention for LDDD were acquired by a comprehensive search in PubMedCentral, MEDLINE, EMBASE, BIOSIS, ClinicalTrials.gov, and the FDA trials register. Methodologic quality was assessed and relevant data were retrieved, and appropriate meta-analysis was performed. Two review authors independently selected studies, extracted data, and assessed risk of bias. Results and upper bounds of confidence intervals were compared with predefined clinically relevant differences.ResultsSix relevant randomized controlled trials (RCTs) involving 1,603 patients were identified and reported two year follow-up results. Patients in TDR group compared with lumbar fusion group demonstrated significant improvements in ODI, VAS scores and complication rates at the two year follow-up. Meanwhile, except for operating time in anterior group, intra-operative blood loss, operating time in posterior group, and reoperation rate were without clinical significance between the two groups. In addition, the range of motion (ROM) was maintained within normal ranges after TDR.ConclusionsThe results showed the TDR has significant safety and efficacy comparable to lumbar fusion at two year follow-up. Although superiority compared to fusion could not be proved, by comparing clinical symptoms relieved, motion preserved, and the low reoperation rate during long-term follow-up on TDR, TDR was considered safe and effective. Therefore, the authors suggest adopting TDR on a large scale; with failure of TDR, interbody fusion would be performed.

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.

The new proximal femoral nail antirotation-Asia: early results.

The proximal femoral nail antirotation system was introduced by the Arbeitsgemeinschaft fur Osteosynthesfragen/Association for the Study of Internal Fixation (AO/ASIF) in 2003 and is suitable for treating unstable trochanteric fractures. However, proximal femoral nail antirotation was designed according to the geometric proportions of the White population, and it is known that important differences exist between Asians and Americans with regard to femoral geometry. Reports of serious postoperative complications also exist when used for the elderly Asian population. Therefore, geometrical mismatch between proximal femoral nail antirotation and the femora of Asians has led the AO/ASIF to design a new proximal femoral nail antirotation for Asia with adapted sizes and geometry. This article reports early clinical results of using proximal femoral nail antirotation for Asians in 84 consecutive patients to stabilize unstable trochanteric fractures (AO classification, 31.A2 and A3). Patients were followed up for an average 8 months (range, 4-11 months). Intraoperative and postoperative complications, surgical details, and outcome measurements were evaluated. Fractures were treated by closed reduction and intramedullary fixation. The proximal femoral nail antirotation Asia position was ideal in 80 cases (95%). No patients showed complication related to the mismatch between the nail and femora. The mean time to bone healing was 14 weeks. Functionally, 90% of the patients regained pretrauma mobility. According to the Harris hip scoring system, 63 patients (78%) had an excellent or good outcome. The new proximal femoral nail antirotation Asia yields better results in the treatment of unstable trochanteric fractures in elderly patients by closely matching Asian femoral anatomy and thereby reducing complications related to the implants.

Systematic Review and Meta-analysis of Randomized Controlled Trials: Comparison of Total Disk Replacement With Anterior Cervical Decompression and Fusion

The authors performed a systematic review and meta-analysis to evaluate whether there is a beneficial clinical effect of total disk replacement compared with anterior cervical diskectomy and fusion for the treatment of single-level symptomatic cervical disk disease. A comprehensive literature search of multiple databases, including PubMed (1966-2011), Cochrane Controlled Trials Register (CENTRAL; issue 1, 2011), and Embase (1984-2011), was conducted to identify studies that met the inclusion criteria. Methodologic quality was assessed and relevant data were retrieved, and if appropriate, meta-analysis was performed. Eight randomized controlled trials were identified; six of the 8 reported 24-month follow-up results. At 24 months, total disk replacement was demonstrated to be more beneficial for patients compared with anterior cervical diskectomy and fusion for the following outcomes: overall success rate (odds ratio [OR], 1.79; 95% confidence interval [CI], 1.37-2.33; P<.0001), overall reoperation rate (OR,.36; CI, .21-.61; P=0), reoperation rate for revision (OR, .12; CI, .02 to .64; P=.01), and visual analog scale neck pain scores (standard mean differences [SMD], -.48; CI, -.91 to -.05; P=.03). Other outcomes, including Neck Disability Index scores (SMD, -.02; CI, -.44 to .27; P=.67) and visual analog scale arm pain scores (SMD, -.21; CI, -.63 to .22; P=.34), demonstrated no differences between the 2 groups. For patients with single-level symptomatic cervical disk disease, total disk replacement was found to be more effective than anterior cervical diskectomy and fusion in the 2 outcomes of overall success rate and overall reoperation rate at 24 months. Long-term results also showed total disk replacement trended to be more effective than anterior cervical diskectomy and fusion in some aspects.

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.

Anterior Reconstruction With Nano-hydroxyapatite/polyamide-66 Cage After Thoracic and Lumbar Corpectomy

Cages are used to regain stability of the anterior spinal column following vertebrectomy, which could prevent significant donor-site morbidity from the iliac autograft harvesting and the risk of disease transmission associated with the allograft. The hollow, porous, cylindrical nanohydroxyapatite/polyamide 66 (n-HA/PA66) cage is a new nonmetallic cage device made by combining nanohydroxyapatite with polyamide 66. Few studies have examined its effectiveness and outcomes over a follow-up >2 years.We retrospectively studied 51 consecutive patients with acute traumatic thoracic or lumbar burst fracture who underwent anterior reconstruction with the n-HA/PA66 cage following single-level corpectomy. Radiologic parameters (radiographs and 3-dimensional computed tomography scans) preoperatively and at 1 week and >2 years postoperatively, as well as clinical outcome parameters (SF-36 scores), were analyzed. Mean kyphosis correction in the segment within the cage was 11.8°±7.1°, and mean loss of correction at last follow-up was 1.9°±2.1°. Osseous fusion was achieved in 90.2% of patients, and severe cage subsidence (settling >2 mm) was observed in 19.6% of patients at final follow-up. Significant differences were found in 7 of 8 health dimensions of the SF-36 between neurologically intact patients and neurologically injured patients. Our clinical results indicate that the n-HA/PA66 cage is an effective device for reconstruction after anterior thoracic and lumbar vertebral resection, resulting in a high rate of successful osseous fusion and a low proportion of severe cage subsidence.

Pre- and postoperative spinopelvic sagittal balance in adolescent patients with lenke type 5 idiopathic scoliosis.

Study Design. A retrospective study. Objective. To investigate the preoperative spinopelvic sagittal alignment in Lenke 5 patients with adolescent idiopathic scoliosis (AIS), and analyze how it alters after posterior correction. Summary of Background Data. The structural thoracolumbar or lumbar curve may change the local sagittal alignment thereby altering the sagittal balance in Lenke 5 patients with AIS. However, few studies have evaluated the spinopelvic sagittal alignment before and after the surgery in these patients. Methods. Forty-eight Lenke 5 patients with AIS who underwent posterior correction and fusion were included in this study. Preoperative and postoperative radiographs were reviewed measuring both the coronal and sagittal parameters. Three pelvic sagittal states (anteverted, normal, or retroverted) were evaluated according to the magnitude relationship of individual pelvic tilt with pelvic incidence (PI). Both the coronal and sagittal parameters between different pelvic sagittal states were compared. The alterations of these parameters by surgery would also be analyzed. Results. The mean follow-up was 1.8 years. Preoperatively, the mean PI was 44.3° with a pelvic tilt of 4.1°. There was 48% patients showing the anteverted pelvis, whereas the remaining 52% showing normal. The patients with anteverted pelvis showed a smaller PI and more distal lower end vertebra than normal pelvis ones. Logistic regression analysis revealed PI (odds ratio [OR] = 0.62, P = 0.024) and lower end vertebra (OR = 2.1, P = 0.037) were significantly associated with the risk of developing anteverted pelvis. The pelvic tilt was significantly increased and 61% of patients with preoperative anteverted pelvis had recovered. Logistic regression analysis revealed PI (OR = 0.7, P = 0.034) and lower instrumented vertebra (OR = 6.5, P = 0.002) were significantly associated with the risk of postoperative uncovered of anteverted pelvis. Conclusion. Anteverted pelvis appears in almost half of Lenke 5 patients with AIS, especially in who have smaller PI or distal lower end vertebra. The abnormal pelvic sagittal state will be generally corrected by posterior correction surgery except for patients with a PI less than 39° or a lower instrumented vertebra that extends to L5. Level of Evidence: 4

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.