Shibao Lu

Biomechanical effect of interspinous dynamic stabilization adjacent to single-level fusion on range of motion of the transition segment and the adjacent segment

BACKGROUND Despite numerous biomechanical studies have been carried out on dynamic stabilizers, there is very little information on their hybrid application, especially when combined interspinous dynamic stabilization with single-level fusion. The aim of this study is to assess the biomechanical effect of interspinous dynamic stabilization adjacent to single-level fusion on range of motion of the transition segment and the adjacent segment. METHODS Six fresh lumbosacral spines (L2-S1) were tested in the following sequence: 1) intact (Construct A); 2) fusion in L5/S1 and intact in L4/5 (Construct B); 3) fusion in L5/S1 and unstable state in L4/5 (Construct C); 4) fusion in L5/S1 and Coflex in L4/5 (Construct D). Range of motion (at L3/4 and L4/5) was recorded and calculated. FINDINGS Range of motion in L3/4 in the four constructs showed no difference under all motion states. Under flexion/extension, the range of motion of L4/5 in Construct B and Construct C increased, while the range of motion of L4/5 in Construct D decreased compared with Construct A. Compared with Construct D, the range of motion of L4/5 in Constructs B and C showed a significant increase. Under lateral bending and axial rotation, Construct A showed similar range of motion of L3/4 compared with other constructs. INTERPRETATION Fusion combined with Coflex is able to stabilize the transition segment and restrict flexion and extension in that segment, while having no significant effect on the range of motion of the adjacent segment or the range of motion of the transition segment under lateral bending and axial rotation.

Clinical and magnetic resonance imaging predictors of the surgical outcomes of patients with cervical spondylotic myelopathy

OBJECTIVE To determine whether clinical characteristics and signal and morphologic changes on magnetic resonance (MR) images of the spinal cord (SC) are associated with surgical outcomes for cervical spondylotic myelopathy (CSM). PATIENTS AND METHODS A total of 113 consecutive patients with cervical myelopathy underwent cervical decompression surgery in our hospital from January 2015 to January 2018. All patients with preoperative MR images available for review were recruited for this study. Research data included patient sex, age, duration of symptoms, surgical approach, compression level, preoperative mJOA (modified Japanese Orthopaedic Association) score, postoperative mJOA recovery rate, and complications. Imaging data included signal changes on T2-weighted MRI images (grade and extension on sagittal images, four types of signal changes on axial images according to the Ax-CCM system), SC compression, transverse area of the SC, and compression ratio. The t-test, Mann-Whitney U-test, Kruskal-Wallis H - test, analysis of variance, and regression analysis were used to evaluate the effects of individual predictors on surgical outcomes. RESULTS The study cohort included 85 males and 27 females with a mean age of 60.92 ± 8.93 years. The mean mJOA score improved from 10.24 ± 1.69 preoperatively to 15.11 ± 2.05 at the final follow-up (p <  0.001). Patients in the poor outcome group were more likely to present with a longer duration of symptoms (p <  0.001) and smaller transverse area of the SC (p <  0.001). Bright T2-weighted high signal changes (T2HSCs), multisegmental high signal changes on sagittal MR images, and fuzzy focal T2HSCs on axial MR images were associated with a poor outcome (p < 0.001, p = 0.005, p <  0.001, respectively). The maximum SC compression and compression ratio were not reliable predictors of surgical outcomes (p =  0.375, p =  0.055, respectively). The result of multivariate stepwise logistic regression showed that a longer duration of symptoms, multisegmental T2HSCs on sagittal MR images and fuzzy focal T2HSCs on axial MR images were significant risk factors of poor outcomes (p < 0.001, p = 0.049, p =  0.016, respectively). CONCLUSION A longer duration of symptom, multisegmental T2HSCs on sagittal MR images, and fuzzy focal T2HSCs on axial MR images were highly predictive of a poor surgical outcome for CSM. Smaller transverse area of the SC and bright T2HSCs were also associated with the prognosis of CSM.

Evaluation of Hyperbaric Oxygen Treatment in Acute Traumatic Spinal Cord Injury in Rats Using Diffusion Tensor Imaging

This study aimed to evaluate the therapeutic effect of hyperbaric oxygen (HBO) on acute spinal cord injury (SCI) by measuring the in vivo diffusion tensor imaging (DTI) parameters apparent diffusion coefficient (ADC) and fractional anisotropy (FA) and observing diffusion tensor tractography (DTT) of fiber bundle morphology. The rats were randomly divided into sham-operated (SH), SCI, and SCI and hyperbaric oxygen treatment (SCI + HBO) groups (n = 6 in each group). The Basso-Bettie-Bresnahan (BBB) score was used to evaluate motor function recovery, and DTI was performed on days 3, 7, 14, and 21 after surgery. BBB scores and FA values decreased significantly after SCI, while the two values significantly improved in the SCI + HBO group compared with the SCI group on days 7, 14, and 21. ADC increased significantly on days 14 and 21 postoperatively in the SCI group compared with the SH group but did not significantly differ between the SCI and SCI + HBO groups at any time point. BBB scores had the same variation trend with ADC values and FA values in all three groups. In the SH group, DTT showed a well-organized spinal cord, but the spinal cord showed interruptions at sites of injury after SCI. In conclusion, HBO promotes the recovery of neuronal function after SCI. Parameters of DTI, especially FA, can quantitatively evaluate the efficacy of HBO treatment in SCI, while DTT enables the visualization of the fiber tracking of spinal cord tracts.

Long-term clinical results following Charite III lumbar total disc replacement

BACKGROUND CONTEXT Lumbar total disc replacement (TDR) operation represents an alternative to lumbar fusion for the treatment of symptomatic lumbar intervertebral disc degeneration and has gained increasing attention in recent years. PURPOSE This study aimed to assess clinical outcomes in a cohort of patients with TDR and the long-term survival rate of the prostheses. STUDY DESIGN This is a retrospective, single-center clinical study. PATIENT SAMPLE The sample comprised 30 patients, giving a total of 35 prostheses after an average follow-up (FU) of 15.2 years following TDR, which was performed for the treatment of lumbar degenerative disc disease. OUTCOME MEASURES Clinical evaluation included visual analog scale (VAS) and the Oswestry Disability Index (ODI). Radiological parameters of intervertebral disc height (IDH), range of motion (ROM), lumbar lordosis, lumbar scoliosis, and prosthesis position were evaluated in surgical and adjacent levels. Complications and re-operation rates were also assessed. METHODS Clinical evaluation and radiological parameters were evaluated preoperatively and at final FU. All data were collected by members of our department, including research assistants and nurses who were not involved in the decision making of this study. RESULTS Thirty of the 35 patients participated in the final FU. The cumulative survival rate of the prosthesis at a mean FU of 15.4 years was 100%. The clinical success rate was 93.3%. The VAS and ODI scores at final FU were significantly lower than preoperatively (p<.001). The average ROM of the operated and superior adjacent segment decreased significantly at the final FU, whereas the inferior adjacent segment was not affected. The IDH of all surgical and adjacent levels were well maintained at the final FU. Ten patients had a lumbar scoliosis >3° and the mean angle was 8.5°, of which 7 had left convex curvature. Three prostheses were offset more than 5 mm from the midline on the coronal plane. Four prostheses showed subsidence. Twenty-six operative segments and five adjacent segments showed heterotopic ossification. Two patients of the total 35-patient cohort underwent a secondary operation. CONCLUSIONS Satisfactory clinical results and good prosthesis survival can be achieved in the long term. Lumbar TDR surgeries also have the potential to reduce the incidence of adjacent segment disease.

Prospective Clinical and Radiographic Results of Activ L Total Disk Replacement at 1- to 3-Year Follow-up.

Study Design: A prospective clinical study. Objective: To assess the clinical and radiographic results of activ L total disk replacement (TDR) on degenerative disk diseases. Summary of Background Data: There are few reports on Activ L TDR, and this is the first in China. Materials and Methods: From March 2009 to March 2012, 32 patients with degenerative disk disease underwent either monosegmental or bisegmental lumbar TDR, which was documented in a prospective observational mode. Clinical success was defined as disability [Oswestry Disability Index (ODI)] improvement of at least 15 points versus baseline, no device failure, no major complications, no neurological deterioration. Additional clinical parameters as Visual Analogue Scale and Oswestry Disability Index (ODI) were evaluated preoperatively and postoperatively (1, 2, and 3 y). Radiographic parameters as range of motion (ROM) and intervertebral disk height (IDH) of the index and adjacent segments were also carried out. Prosthesis subsidence and heterotopic ossification were observed during the follow-up period. Work status was tracked for all patients. Results: Overall, 30 patients (93.7%) were available for a mean follow-up of 28.8 months (12–46 mo) and had complete radiographic data. Their mean age was 45.1 years (32–58 y). At 3 years postoperatively, the success rate was 86.7% (26/30). After surgery, clinical parameters as Visual Analogue Scale score for back and leg pain, and ODI score showed statistically significant improvement (P<0.001), and the situation was well maintained during the follow-up time points. At 3 years postoperatively, the mean IDH at the index segment and upper and lower adjacent segments were 12.87, 12.61, and 11.62 mm, respectively, showing no significant difference compared with preoperative data (P1=0.0597, P2=0.6669, P3=0.9813). The ROM of the index and upper adjacent segment showed a slight but significant increase at the 3-year follow-up compared with baseline (P1=0.0128, P2=0.0007). The changes of ROM at the lower adjacent segment were not significant (P=0.6637). Tears of the iliac vein were observed in 2 patients. Prosthesis subsidence was observed in 3 patients (1 at 12 mo postoperatively, 1 at 24 mo postoperatively, and 1 at 32 mo postoperatively). Heterotopic ossification was observed in 1 patient at 36 mo postoperatively. At the 3-year follow-up, only 8 patients went back to their original work, and 15 patients changed jobs, whereas the last 7 patients stopped working. Conclusions: The 1- to 3-year follow-up of this cohort of patients showed satisfactory clinical outcomes. The IDHs at index and adjacent segments were well maintained after the surgery. The ROM at the lower adjacent segment remained unchanged, but the ROM at the index and upper adjacent segments showed a slight increase. The long-term results of activ L TDR was to be investigated.