Satisfactory immediate spontaneous correction may not mean satisfactory final results for moderate TL/L curves after selective thoracic fusion in AIS patients.

BACKGROUND: Few studies have focused on the chronic spontaneous behavior of the unfused TL/L curve during follow-up. The purpose of the present study was to explore the behavior of the unfused TL/L curve during a long-term follow-up to identify the risk factors for correction loss. METHODS: Sixty-four age-matched female AIS patients undergoing selective thoracic fusion were enrolled. Patients were divided into 2 groups according to whether there was correction loss. Risk factors for correction loss of the unfused TL/L curves were analyzed. The relationship and difference between the immediate postoperative thoracic and TL/L Cobb angles were explored. RESULTS: The TL/L Cobb angle was 28.17° before surgery, 8.60° after surgery, and 10.74° at the final follow-up, with a correction loss of 2.14°. Each subgroup contained 32 cases. A smaller postoperative TL/L Cobb angle was the only risk factor that was independently associated with TL/L correction loss. In the LOSS group, there was a significant difference and no correlation between the immediate postoperative TL/L and the thoracic Cobb angle. In the NO-LOSS group, there was a moderate correlation and no difference between them. CONCLUSION: A smaller immediate postoperative TL/L Cobb angle may have been associated with TL/L correction loss during the long-term follow-up. Thus, good immediate postoperative spontaneous correction may not mean a satisfactory outcome at the final follow-up after STF. Mismatch between thoracic and TL/L Cobb angles immediately after surgery may also be related to correction loss of the unfused TL/L curves. Close attention should be paid in case of deterioration.

Standalone oblique lateral interbody fusion vs. combined with percutaneous pedicle screw in spondylolisthesis.

BACKGROUND: To compare standalone oblique lateral interbody fusion (OLIF) vs. OLIF combined with posterior bilateral percutaneous pedicle screw fixation (OLIF combined) for the treatment of lumbar spondylolisthesis. METHODS: This was a retrospective study of patients who underwent standalone OLIF or combined OLIF between 07/2014 and 08/2017 at two hospitals in China. Direct decompressions were not performed. Visual analog scale (VAS), Oswestry Disability Index (ODI), satisfaction rate, anterior/posterior disc heights (DH), foraminal height (FH), foraminal width (FW), cage subsidence, cage retropulsion, fusion rate, and complications were analyzed. All imaging examinations were read independently by two physicians and the mean measurements were used for analysis. RESULTS: A total of 73 patients were included: 32 with standalone OLIF and 41 with combined OLIF. The total complication rate was 25.0% with standalone OLIF and 26.8% with combined OLIF. There were no differences in VAS and ODI scores by 2 years of follow-up, but the scores were better with standalone OLIF at 1 week and 3 months (P < 0.05). PDH and FW was smaller in the combined OLIF group compared with the standalone OLIF group before and after surgery (all P < 0.05). There were significant differences in FH before surgery and at 1 week and 3 months between the two groups (all P < 0.05), but the difference disappeared by 2 years (P = 0.111). Cage subsidence occurred in 7.3% (3/41) and 7.3% (3/41) of the patients at 3 and 24 months, respectively, in the combined OLIF group, compared with 6.3% (2/32) and 15.6% (5/32), respectively, in the standalone OLIF group at the same time points (P = 0.287). There was no cage retropulsion in both groups at 2 years. The fusion rate was 85.4%(35/41) in the combined OLIF group and 84.4% (27/32) in the standalone OLIF group at 3 months(P = 0.669). At 24 months, the fusion rate was 100.0% in the combined OLIF group and 93.8% (30/32) in the standalone OLIF group (P = 0.066). CONCLUSION: Standalone OLIF may achieve equivalent clinical and radiological outcomes than OLIF combined with fixation for spondylolisthesis. The rate of complications was similar between the two groups. Patients who are osteoporotic might be better undergoing combined rather than standalone OLIF. The possibilty of proof lies within a future prospective study, preferably an RCT.

Quantitative analysis of paraspinal muscle atrophy after oblique lateral interbody fusion alone vs. combined with percutaneous pedicle screw fixation in patients with spondylolisthesis.

BACKGROUND: There is no available literature for comparison on muscle atrophy between the "stand-alone" oblique lateral interbody fusion (OLIF) and regular OLIF (i.e., combined with percutaneous pedicle screws fixation (PPSF) in patients with spondylolisthesis). This study aimed to identify changes in back muscle atrophy between the two surgeries. METHODS: This was a retrospective cohort study of patients who underwent OLIF or OLIF+PPSF at Beijing Jishuitan Hospital and Shanghai ChangZheng Hospital between 07/2014 and 10/2017. Computed tomography (CT) was used to measure functional cross-sectional area (FCSA) and fat infiltration percentage (FIP) of the multifidus and erector spinae before and 24 months after surgery. RESULT: There were no differences in FCSA and FIP between OLIF (n = 32) and OLIF+PPSF (n = 41) groups before surgery. In the OLIF group, the multifidus and erector spinae FCSA and FIP did not change at 24 months (FCSA: multifidus: from 8.59 ± 1.76 to 9.39 ± 1.74 cm2, P = 0.072; erector spinae: from 13.32 ± 1.59 to 13.55 ± 1.31 cm2, P = 0.533) (FIP: multifidus: from 15.91 ± 5.30% to 14.38 ± 3.21%, P = 0.721; erector spinae: from 11.63 ± 3.05% to 11.22 ± 3.12%, P = 0.578). In the OLIF+PPSF group, the multifidus and erector spinae FCSA decreased (multifidus: from 7.72 ± 2.69 to 5.67 ± 1.71 cm2, P < 0.001; erector spinae: from 12.60 ± 2.04 to 10.15 ± 1.82 cm2, P < 0.001), while the FIP increased (multifidus: from 16.13 ± 7.01% to 49.38 ± 20.54%, P < 0.001; erector spinae: from 11.93 ± 3.22% to 22.60 ± 4.99%, P < 0.001). The differences of FCSA and FIP between the two groups at 24 months were significant (all P < 0.001). The patients in the standalone OLIF group had better VAS back pain, and JOA scores than the patients in the OLIF combined group (all P < 0.05) at 1 week and 3 months after surgery. There were two cases (4.9%) of adjacent segment degeneration in the OLIF combined group, while there was no case in the OLIF alone group. CONCLUSIONS: Standalone OLIF had better clinical outcomes at 1 week and 3 months than OLIF+PPSF in patients with spondylolisthesis. OLIF may not result in paraspinal muscle atrophy at 24 months after surgery.

Clinical evaluation of the polymethylmethacrylate-augmented thoracic and lumbar pedicle screw fixation guided by the three-dimensional navigation for the osteoporosis patients.

PURPOSE: To evaluate the safety and efficacy of three-dimensional (3D) navigation-guided polymethylmethacrylate (PMMA)-augmented thoracic and lumbar pedicle screw fixation for the osteoporotic patients. METHODS: 27 consecutive osteoporosis patients with a variety of spinal disorders who underwent 3D navigation-guided PMMA-augmented pedicle screw fixation were evaluated clinically and radiologically in the perioperative and 1-year follow-up period. The improvement of Japanese Orthopaedic Association (JOA) scores was analyzed. PMMA leakage and other complications were inspected intraoperatively and postoperatively. Screw loosening and bone fusion were evaluated radiographically during follow-up. RESULTS: 8 patients had thoracic and lumbar fractures; 18 patients had degenerative spinal disorders; one patient had revision surgery. One patient died of postoperative pneumonia. Each of the other 26 patients was followed up regularly at 3, 6, 12 and 18 months postoperatively. The mean therapeutic improvement rate is 39.6% evaluated by JOA scores. 2 patients (7.4%) had leakage into the spinal canal in front of the posterior longitudinal ligament and two patients (7.4%) had leakage into the prevertebral soft tissue inspected by the postoperative CT scans. No pedicle cortex breach and cement leakage surrounding pedicle cortex were observed. None of patients complained of dyspnoea and showed evidence of pulmonary embolism. Bone fusions were found in 20 patients (bony fusion rate 76.9%) at the 12-month follow-up and no screw loosening occurs. CONCLUSION: The results show favorable outcome using 3D navigation-guided PMMA-augmented thoracic and lumbar pedicle screw fixation for the osteoporosis patients both clinically and radiologically.

[Cause analysis of back pain after vertebroplasty or kyphoplasty].

OBJECTIVE: To analyze the causes of back pain after vertebroplasty or kyphoplasty. METHODS: 1 863 patients with back pain who underwent vertebroplasty or kyphoplasty from Jan. 2004 to Dec. 2014 in Department of Spine Surgery, Beijing Jishuitan Hospital, were followed up for least 3 months after surgery with their back pain evaluated by VAS scores. Related information including preoperative, operative and postoperative factors was gathered. The VAS at last follow-up over 5 or the symptom relief less than 50% was considered as non-relieved, the correlations between the symptom relief and potential influencing factors were analyzed by the Spearman correlation. RESULTS: Symptom relief was only correlated with postoperative complications (P<0.001). The back pain in 283 cases (15.2%) had not been relieved. Among them, 87 cases got fractures in other vertebrae (adjacent vertebrae in 67 cases, non-adjacent vertebrae in 20 cases); 3 cases got nonunion in the operated vertebrae; 1 case got postoperative infection; 6 cases got misdiagnosis and the other 186 cases had no known causes for the unrelieved pain. CONCLUSIONS: Postoperative back pain after vertebroplasty or kyphoplasty may have variable causes, and some of which have not been entirely understood. If the symptoms are not alleviated or even aggravate after active symptomatic treatment and anti-osteoporotic therapy, underlying causes such as re-fracture, nonunion, infection, pathologic fracture should be sought out.

Enhanced pyroptosis induction with pore-forming gene delivery for osteosarcoma microenvironment reshaping.

Osteosarcoma is the most common malignant bone tumor without efficient management for improving 5-year event-free survival. Immunotherapy is also limited due to its highly immunosuppressive tumor microenvironment (TME). Pore-forming gasdermins (GSDMs)-mediated pyroptosis has gained increasing concern in reshaping TME, however, the expressions and relationships of GSDMs with osteosarcoma remain unclear. Herein, gasdermin E (GSDME) expression is found to be positively correlated with the prognosis and immune infiltration of osteosarcoma patients, and low GSDME expression was observed. A vector termed as LPAD contains abundant hydroxyl groups for hydrating layer formation was then prepared to deliver the GSDME gene to upregulate protein expression in osteosarcoma for efficient TME reshaping via enhanced pyroptosis induction. Atomistic molecular dynamics simulations analysis proved that the hydroxyl groups increased LPAD hydration abilities by enhancing coulombic interaction. The upregulated GSDME expression together with cleaved caspase-3 provided impressive pyroptosis induction. The pyroptosis further initiated proinflammatory cytokines release, increased immune cell infiltration, activated adaptive immune responses and create a favorable immunogenic hot TME. The study not only confirms the role of GSDME in the immune infiltration and prognosis of osteosarcoma, but also provides a promising strategy for the inhibition of osteosarcoma by pore-forming GSDME gene delivery induced enhanced pyroptosis to reshape the TME of osteosarcoma.

Diabetes and intervertebral disc degeneration: A Mendelian randomization study.

Introduction: Intervertebral disc degeneration (IVDD) is an important contributor of low back pain, which represents one of the most disabling symptoms within the adult population. Recently, increasing evidence suggests the potential association between Type 2 diabetes mellitus (T2DM) and IVDD. However, the causal relationship between these two common diseases remains unclear. Methods: We conducted a two-sample Mendelian randomization (MR) analysis to assess the causal association between T2DM and IVDD. Sensitivity analysis was performed to test for heterogeneity and horizontal pleiotropy. Multivariable MR was also conducted to adjust for the effect of BMI on IVDD. Results: A total of 128 independent single-nucleotide polymorphisms (SNPs) that were significantly associated with T2DM were selected as instrumental variables in univariable MR analysis. Our results showed that patients with T2DM had a higher risk of developing IVDD (OR, 1.069; 95% CI, 1.026-1.115; p = 0.002). The relationship remained stable in sensitive analysis including multivariable MR, which implicated the direct causal effect of T2DM on IVDD (OR, 1.080; 95% CI, 1.041-1.121; p < 0.001) after adjusting for BMI. Conclusions: MR analysis indicated a causal effect of T2DM on IVDD, and the effect persisted even when we accounted for the impact of BMI.

Clinical and Radiographic Comparison of Oblique Lateral Lumbar Interbody Fusion and Minimally Invasive Transforaminal Lumbar Interbody Fusion in Patients with L4/5 grade-1 Degenerative Spondylolisthesis.

OBJECTIVES: To compare the clinical and radiographic outcomes of oblique lateral lumbar interbody fusion and minimally invasive transforaminal lumbar interbody fusion in patients with grade-1 L4/5 degenerative spondylolisthesis. METHODS: Based on the inclusion and exclusion criteria, the comparative analysis included consecutive patients with grade-1 degenerative spondylolisthesis who underwent oblique LIF (OLIF, n = 36) or minimally invasive transforaminal LIF (MI-TLIF, n = 45) at the Department of Spine Surgery, Beijing Jishuitan Hospital from January 2016 to August 2017. Patient satisfaction Japanese Orthopaedic Association score, visual analog scale (VAS) scores for back and leg pain, Oswestry disability index (ODI), radiographic outcomes including anterior/posterior disc heights (ADH/PDH), foraminal height (FH), foraminal width (FW), cage subsidence, cage retropulsion, and fusion rate were assessed during a 2-year follow-up. Continuous data are presented as mean ± standard deviation and were compared between groups using the independent sample t-test. Categorical data are presented as n (%) and were compared between groups using the Pearson chi-squared test or Fisher's exact test. Repetitive measurement and analysis of variance was employed in the analysis of ODI, back pain VAS score, and leg pain VAS score. Statistical significance was defined as p < 0.05. RESULTS: The OLIF and MI-TLIF groups comprised 36 patients (age, 52.1 ± 7.2 years; 27 women) and 45 patients (age, 48.4 ± 14.4 years; 24 women), respectively. Satisfaction rates at 2 years post procedure exceeded 90% in both groups. The OLIF group had less intraoperative blood loss (140 ± 36 vs 233 ± 62 mL), lower back pain VAS score (2.42 ± 0.81 vs 3.38 ± 0.47), and ODI score (20.47 ± 2.53 vs 27.31 ± 3.71) at 3 months follow-up (with trends toward lower values at 2 years follow-up), but higher leg pain VAS scores at all postoperative time points than the MI-TLIF group (all p < 0.001). ADH, PDH, FD, and FW improved in both groups post-surgery. At the 2 year follow-up, the OLIF group had a higher rate of Bridwell grade-I fusion (100% vs 88.9%, p = 0.046) and lower incidences of cage subsidence (8.33% vs 46.67%, p < 0.001) and retropulsion (0% vs 6.67%, p = 0.046) than the MI-TLIF group. CONCLUSIONS: In patients with grade-I spondylolisthesis, OLIF was associated with lower blood loss and greater improvements in VAS for back pain and ODI and radiologic outcomes than MI-TLIF. The OLIF is more suitable for these patients with low back pain as the main symptoms are accompanied by mild or no leg symptoms before operation.

Where should Scoliometer and EOS Imaging be Applied when Evaluating Spinal Rotation in Adolescent Idiopathic Scoliosis -A Preliminary Study with Reference to CT Images.

STUDY DESIGN: Retrospective study. OBJECTIVE: Our purpose was to evaluate spinal rotation measurement by scoliometer or EOS Imagings with reference to that by CT images, and to clarify their applicability in clinical practice. METHODS: Patients with adolescent idiopathic scoliosis (AIS) who were indicated for surgery were enrolled and the informed consents were obtained. The angle of trunk rotation (ATR) was measured by the scoliometer. Apical vertebral rotation (AVR) was measured with EOS Imaging and CT images. Paired T tests were used to compare the measurements between ATR or AVR-EOS and AVR-CT. Pearson correlation analysis was performed to explore the relationship between ATR or AVR-EOS and AVR-CT. Then subgroup analysis was performed. RESULTS: Forty-seven consecutive AIS patients with 62 curves were identified. In the whole group, the ATR, as well as AVR-EOS, was significantly smaller than the AVR-CT. Both ATR and AVR-EOS correlated with AVR-CT, although AVR-EOS correlated better. In thoracic group, there was no significant difference between ATR and AVR-CT (P = .236). A significant correlation was found between ATR and AVR-CT(r = .574, P < .001). In TL/L group, no significant difference was noted between AVR-EOS and AVR-CT (P = .414), and a significant correlation was found between AVR-EOS and AVR-CT(r = .824, P < .001). CONCLUSION: ATR by scoliometer is numerically similar to AVR by CT and may evaluate the spinal rotation more appropriately in thoracic spine. AVR by EOS is numerically similar to AVR by CT and may be more applicable in TL/L spine. Appropriate methods could be selected according to the location of the curve.

Longitudinal Spinous-Splitting Laminoplasty with Coral Bone for the Treatment of Cervical Adjacent Segment Degenerative Disease: A 5-Year Follow-up Study.

This study was designed to analyze the causes of cervical adjacent segment degenerative disease (ASDis), evaluate the surgical outcomes of longitudinal spinous-splitting laminoplasty with coral bone (SLAC) during cervical reoperation, and accumulate data on reoperation with SLAC in a primary hospital. Based on the inclusion and exclusion criteria, we conducted a retrospective study involving 52 patients who underwent cervical reoperation for ASDis using SLAC at the spinal surgery department of the Beijing Jishuitan Hospital from 1998 to 2014. Among them, 39 were treated with anterior cervical fusion and internal fixation during the first operation (anterior cervical corpectomy with fusion [ACCF], n = 24; anterior cervical discectomy and fusion [ACDF], n = 11; and cervical disc arthroplasty [CDA], n = 4). Outcomes were the Japanese Orthopaedic Association (JOA) score, neck disability index (NDI) score, upper limb/neck and shoulder evaluated using a visual analogue scale (VAS), and rates of ASDis. In patients who underwent an anterior cervical approach in the first instance, the incidence of ASDis was significantly higher in the C3/4 gap than in the other gaps. In the ACCF group, the lateral radiograph of the cervical spine revealed that the distance between the anterior cervical plate and the adjacent segment disc was <5 mm in 15 (62.5%) cases and five (12.8%) cases, respectively, the internal fixation screws broke into the annulus of the adjacent segment. After the first SLAC, ASDis developed at C2/3 and C3/4 in four (30.8%) and eight (61.5%) cases, respectively. After reoperation, all cases were followed up for >5 (average, 6.2) years. The pre-reoperation and last follow-up values were as follows: mean Japanese Orthopaedic Association score, 10.2 ± 1.5 vs 15.5 ± 0.7 (P = 0.03); neck disability index, 26.2 vs 13.6 points (P = 0.01); upper-limb visual analog scale (VAS) score, 6.1 vs 2.6 points (P = 0.04); and neck and shoulder VAS score, 6.6 vs 2.1 points (P = 0.03). SLAC is a simple technique in which the local anatomy is clearly visible and satisfactory clinical outcomes are obtained.

[One-stage posterior approach spinal reconstruction for severe lumbar burst fracture].

OBJECTIVE: To evaluate the clinical therapeutic outcomes for severe burst fracture of lumbar vertebrae via a posterior approach for one-stage spinal "three-column" reconstruction. METHODS: An retrospective analysis of data was performed for 21 patients with severe burst fracture of lumbar vertebrae undergoing a posterior approach for one-stage spinal "three-column" reconstruction from 2005 to 2010. It was compared with previous 15 cases undergoing a staged anteroposterior approach. The operative duration, volume of blood loss, pre- and post-operative imaging measurements of kyphosis and vertebral height and nerve function recovery were evaluated. RESULTS: The values of operative duration and volume of blood loss in the one-stage posterior approach group were significantly less than those of the two-stage anteroposterior approach group [(263 ± 72) min vs (439 ± 75) min, t = -5.303, P < 0.01; (1143 ± 296) ml vs (1471 ± 399) ml, t = -2.169, P = 0.042)]. Statistical significance existed in postoperative kyphosis between two groups [(0.5 ± 2.0)° vs (3.9 ± 2.6)°, t = -3.336, P = 0.003]. Vertebral height had no statistical significance pre- and post-operatively between two groups while restoration of vertebral height did [(0.47 ± 0.19) mm vs (0.26 ± 0.15) mm, t = 2.669, P = 0.015]. CONCLUSION: Posterior approach for one-stage vertebral resection, mesh implantation, pedicle screws and rod internal fixation for reconstructing spinal "three-column" structures offers excellent feasibility and safety. And it may avoid complications associated with an anteroposterior approach for two-stage procedures. The median length of hospital stay is also reduced.

Biomechanical Evaluation of the Transcortical and Transpedicular Trajectories for Pedicle Screw Insertion in Thoracolumbar Fracture Fixation for Ankylosing Spondylitis.

Background: Ankylosing spondylitis (AS) is a chronic disorder characterized by an imbalance between bone formation and resorption. Spinal fractures often occur after minor trauma in patients with AS. For thoracolumbar fractures, transpedicular screw (TPS) fixation through the posterior approach has been suggested. The cortical bone trajectory (CBT) technique has also been used to prevent screw pull-out in patients with poor bone quality. The aim of current study was to assess the biomechanical characteristics of the TPS and CBT technique in thoracolumbar AS fracture fixation by finite element analysis. Methods: The three-dimensional finite element models of the AS spine were created. The CBT and TPS methods of screw insertion were used in AS spinal fracture models. An intact AS spine model was considered the control. An axial force and torsion in rotation, flexion/extension and lateral flexion were applied in all models in CBT, TPS, and control groups. Results: The AS spine showed similar construct stiffness after posterior fixation by CBT and TPS techniques under axial, rotational, and flexion/extension loading conditions. The TPS technique showed better intact stability under all loading conditions. Similarly, the TPS technique provided superior fracture regional stability against axial and rotational loads than did the CBT technique. The maximum von Mises stresses were 1714.4 ± 129.8 MPa and 1208.7 ± 107.3 MPa (p < 0.001), which occurred in the CBT and TPS groups under compressive loading. Conclusions: The TPS technique provides better biomechanical strength under axial, rotational, flexion/extension, and lateral flexion loading than does the CBT technique. Compared with CBT, TPS is more effective in maintaining the stability of AS thoracolumbar fractures from a finite element analysis perspective.

Comparison of Outcomes between Robot-Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion and Oblique Lumbar Interbody Fusion in Single-Level Lumbar Spondylolisthesis.

OBJECTIVE: To compare the safety and effectiveness of robot-assisted minimally invasive transforaminal lumbar interbody fusion (Mis-TLIF) and oblique lumbar interbody fusion (OLIF) for the treatment of single-level lumbar degenerative spondylolisthesis (LDS). METHODS: This is a retrospective study. Between April 2018 and April 2020, a total of 61 patients with single-level lumbar degenerative spondylolisthesis and treated with robot-assisted OLIF (28 cases, 16 females, 12 males, mean age 50.4 years) or robot-assisted Mis-TLIF (33 cases, 18 females, 15 males, mean age 53.6 years) were enrolled and evaluated. All the pedicle screws were implanted percutaneously assisted by the TiRobot system. Surgical data included the operation time, blood loss, and length of postoperative hospital stay. The clinical and functional outcomes included Oswestry Disability Index (ODI), Visual Analog scores (VAS) for back and leg pain, complication, and patient's satisfaction. Radiographic outcomes include pedicle screw accuracy, fusion status, and disc height. These data were collected before surgery, at 1 week, 3 months, 6 months, and 12 months postoperatively. RESULTS: There were no significantly different results in preoperative measurement between the two groups. There was significantly less blood loss (142.4 ± 89.4 vs 291.5 ± 72.3 mL, P < 0.01), shorter hospital stays (3.2 ± 1.8 vs 4.2 ± 2.5 days, P < 0.01), and longer operative time (164.9 ± 56.0 vs 121.5 ± 48.2 min, P < 0.01) in OLIF group compared with Mis-TLIF group. The postoperative VAS scores and ODI scores in both groups were significantly improved compared with preoperative data (P < 0.05). VAS scores for back pain were significantly lower in OLIF group than Mis-TLIF group at 1 week (2.8 ± 1.2 vs 3.5 ± 1.6, P < 0.05) and 3 months postoperatively (1.6 ± 1.0 vs 2.1 ± 1.1, P < 0.05), but there was no significant difference at further follow-ups. ODI score was also significantly lower in OLIF group than Mis-TLIF group at 3 months postoperatively (22.3 ± 10.0 vs 26.1 ± 12.8, P < 0.05). There was no significant difference in the proportion of clinically acceptable screws between the two groups (97.3% vs 96.2%, P = 0.90). At 1 year, the OLIF group had a higher interbody fusion rate compared with Mis-TLIF group (96.0% vs 87%, P < 0.01). Disc height was significantly higher in the OLIF group than Mis-TLIF group (12.4 ± 3.2 vs 11.2 ± 1.3 mm, P < 0.01). Satisfaction rates at 1 year exceeded 90% in both groups and there was no significant difference (92.6% for OLIF vs 91.2% for Mis-TLIF, P = 0.263). CONCLUSION: Robot-assisted OLIF and Mis-TLIF both have similar good clinical outcomes, but OLIF has the additional benefits of less blood loss, less postoperative hospital stays, higher disc height, and higher fusion rates. Robots are an effective tool for minimally invasive spine surgery.

[Adjacent segment mobility after anterior cervical discectomy and fusion].

OBJECTIVE: To investigate the mobility changes of adjacent segments after fusion retrospectively. METHODS: A total of 28 patients underwent standard anterior cervical arthrodesis. The kinematic changes occurred at segments adjacent to cervical arthrodesis through a coral bone graft and plating system. The mean follow-up period was 6.3 ± 1.6 years (3.6 - 10.5). Lateral radiographic views of cervical spine in flexion and extension were obtained at pre-operation and follow-up. Rotational motion at adjacent levels was quantified. RESULTS: Sagittal range of motion (ROM) at adjacent cranial level was 11.2° ± 5.0° at pre-operation and 11.4° ± 6.4° at follow-up. It was not statistically significant (P > 0.01). At adjacent caudal level, ROM was 9.8° ± 5.3°, but 10.2° ± 4.6° at follow-up. But it was not statistically significant (P > 0.01). During the follow-up, entire cervical motion (C2-C7) decreased significantly from 46.8° ± 13.4° to 36.8° ± 9.6° in single-level fusion group, but from 48.6° ± 14.6° to 39.9° ± 7.2° in double-level fusion group. CONCLUSION: The assumption of an iatrogenically elevated adjacent level mobility by cervical fusion is refuted by the present study.

[Short-term clinical outcome of modified expansive open-door cervical laminoplasty preserving posterior extensor musculature inserted into C2 and C7 spinous process].

OBJECTIVE: To assess the effect of modified cervical expansive open-door laminoplasty preserving the posterior extensor musculature inserted into the C2 and C7 spinous process upon maintaining the cervical lordotic alignment and axial syndrome and to determine whether preserving the posterior extensor musculature inserted into C2 and C7 spinous process can reduce the complications. METHODS: Twenty-eight patients undergoing modified cervical expansive open-door laminoplasty preserving the posterior extensor musculature inserted into the C2 and C7 spinous process and 21 patients undergoing conventional C3-C7 cervical expansive open-door laminoplasty were investigated in pre-operative, post-operative and 3-month follow-up. The investigators assessed the effects of two different cervical laminoplasty types in the recovery rate of JOA score, the changes of Cobb angle and Ishihara's index, axial syndrome, operating duration and intra-operative blood loss, analyzed the results in SPSS and tried to find the difference in two operative types. RESULTS: There were the same results in the recovery rate of JOA score and intra-operative blood loss in modified expansive open-door cervical laminoplasty group and the conventional C3-C7 cervical expansive open-door laminoplasty group. The smaller changes of Cobb angle and Ishihara's index in the follow-up of modified laminoplasty group were found. The modified laminoplasty group had fewer patients suffering the axial syndrome in follow-up. The operating duration was shorter in the modified laminoplasty group. CONCLUSION: Preventing muscle injuries in cervical laminoplasty can reduce the incidence of complications. The modified expansive open-door cervical laminoplasty preserving the posterior extensor musculature inserted into C2 and C7 spinous process can protect cervical posterior extensor musculature. This is helpful to maintain the cervical lordotic alignment and reduce the incidence of post-operative axial syndrome.

[Transforaminal lumbar interbody fusion by minimally invasive approach in the treatment of simple foraminal stenosis].

OBJECTIVE: To study the short-term clinical outcome of transforaminal lumbar interbody fusion (TLIF) by minimally invasive approach in the treatment of simple foraminal stenosis (SFS). METHODS: Thirty four cases (M: F = 19: 15) diagnosed with SFS from January. 2007 to March. 2009 were included. Age ranged from 47 to 62 (mean: 57) years old. Patients generally had degenerative changes and decreased disc height on X-ray films at the indexed level. No stenosis within the spinal canal was found on myelograph and CTM. Sagittal images of MRI usually demonstrated narrowed foramina. Selective radiculograph and radicular blocking was used to make the definite diagnosis and to locate the involved nerve root. Double paramedian intermuscular approaches were adopted in all cases. Minimally invasive retractor systems, such as X-Tube and Pipeline etc., were used to facilitate the exposure, pedicle screw instrumentation and TLIF. RESULTS: The average operation time was 2.76 hours. The average blood loss was 387.16 ml. All patients were encouraged to ambulate 2-3 days post-operation. The incisions healed uneventfully. At the final follow-up, instrumentations were maintained in an excellent position in all cases and JOA score improved by 31.14%. CONCLUSIONS: TLIF by minimally invasive approach is an effective method in treating patients with lumbar foraminal stenosis. The short-term clinical outcomes are satisfactory. This approach may avoid the injuries to paraspinal muscles, posterior ligaments, dura and nerve root of the uninvolved side.

Secreted Factors From Intervertebral Disc Cells and Infiltrating Macrophages Promote Degenerated Intervertebral Disc Catabolism.

STUDY DESIGN: Rat nucleus pulposus (NP) cells or annulus fibrosus (AF) cells were stimulated with conditioned media of RAW 264.7 macrophages and vice versa under healthy culture conditions and in the presence of pro-inflammatory mediators. The gene expression of pro-inflammatory mediators, extracellular matrix (ECM)-modifying enzymes, and chemokines, which play important roles in intervertebral disc degeneration (IDD), was determined. OBJECTIVE: To test whether the interaction between native disc cells and infiltrating macrophages accelerates inflammation state, disrupts matrix homeostasis, and promotes inflammatory cells infiltration. SUMMARY OF BACKGROUND DATA: With macrophages infiltration, the disc resident cells would be inevitably exposed to macrophages. Macrophages have been shown to play pro-inflammatory role in the cellular interactions with disc cells under healthy culture conditions. However, the biologic interactions between macrophages and disc cells under degenerated disc inflammatory environment remain unknown. METHODS: Murine Macrophages RAW 264.7 were cultured in the conditioned media of Rat AF or NP cells culture in the presence or absence of IL-1ß stimulation. Similarly, Rat AF or NP cells were also cultured in the conditioned media of Murine Macrophages RAW 264.7 culture in the presence or absence of IFN-γ stimulation. The mRNA levels difference of pro-inflammatory genes, catabolic genes and chemokines genes for AF cells, NP cells and Macrophages RAW 264.7 were analyzed by qRT-PCR, respectively. RESULTS: Compared with serum-free media exposure, RAW 264.7 macrophages exposed to AF or NP cells conditioned media selectively modestly upregulated mRNA levels of the aforementioned cytokines. Exposure of RAW 264.7 macrophages to conditioned media from AF or NP cells with IL-1ß stimulation dramatically increased mRNA levels of all the investigated cytokines. Similarly, compared with serum-free media exposure, AF or NP cells exposed to RAW 264.7 macrophages conditioned media selectively modestly upregulated mRNA levels of the aforementioned cytokines. Exposure of AF or NP cells to conditioned media from RAW 264.7 macrophages with IFN-γ stimulation dramatically increased mRNA levels of all the investigated cytokines. CONCLUSION: The biologic interactions between infiltrating macrophages and native disc cells under degenerated disc inflammatory environment lead to an increasingly severe inflammatory conditions, which may be a self-stimulated process from the macrophages infiltration occurrenceLevel of Evidence: 5.

[Comparison between CT-discography and magnetic resonance imaging in lumbar disc diseases].

OBJECTIVE: To investigate the clinical importance of discography and CT after discography (CTD) in the lumbar disc diseases, and make a comparison between CTD and magnetic resonance imaging (MRI). METHODS: 265 patients with back and leg pain 177 males and 79 females, age 39 +/- 16, underwent discography and CT 2 hours later on 298 discs. All the patients' discs were classified into 7 types according to the findings by discography and CTD. Comprehensive MRI pictures were available in 237 of the 265 patients (with 257 discs); they accepted the MRI classification and were compared with the CT-discographic findings. RESULTS: 245 patients underwent operation, among which 247 discs showed visual lesions during the procedure and 238 cases (96.4%) had their disc diseases diagnosed accurately through discography and CTD. Considering the positive screening rate for the discogenic abnormality, the difference was of statistical significance between the CTD and MRI groups (P < 0.01). MRI was considered to have limited value in the disc diseases with passive discographic finding. CONCLUSION: Discography is an efficient, sound and safe assistant diagnostic tool, which can get some special information about disc. The matched-group study shows that the MRI and CTD can not be re placed by each other. MRI may act as the screening tool for disc diseases, but is inferior to CTD, especially for the contiguous disc structure in the spinal fixation procedure.

[Accuracy of CT-based navigation of pedicle screws implantation in the cervical spine compared with X-ray fluoroscopy technique].

OBJECTIVE: To evaluate the feasibility and accuracy of cervical spine pedicle screw fixation assisted by X-ray fluoroscopy and CT-based navigation system. METHODS: 145 cervical pedicle screws were placed assisted by X-ray fluoroscopy and 159 cervical pedicle screws were placed assisted by CT-based navigation system. Screw positions were evaluated by postoperative CT scans or C-arm X-ray 3 dimensional reconstruction. RESULTS: In the computer- assisted group, 155 (97.5%) screws were found completely within their pedicles compared with 133 (91.7%) correctly placed screws in the X-ray assisted group (P < 0.05). The process of navigation investigated in twenty patients showed that the mean time for registration and surface matching was 3.5 (range from 2 to 8 minutes) minutes and the mean time for screw-marker insertion was 2 (range from 1 to 3.5 minutes) minutes with the mean position deviation 0.31 mm (0.12-0.56 mm) per screw. Only twice C-arm fluoroscopy were performed to verify the accuracy of one screw position intraoperatively. No severe complications like neurovascular lesion occurred in both groups. CONCLUSION: CT-based navigation system can increase the accuracy of cervical pedicle screw implantation significantly.