This study was aimed to compare the mechanical characteristics under different physiological load conditions with three-dimensional finite element model of rigid fixation and elastic fixation in the lumbar. We observed the stress distribution characteristics of a sample of healthy male volunteer modeling under vertical, flexion and extension torque situation. The outcomes showed that there existed 4-6 times pressure on the connecting rod of rigid fixation compared with the elastic fixations under different loads, and the stress peak and area of force on elastic fixation were much higher than that of the rigid fixations. The elastic fixation has more biomechanical advantages than rigid fixation in promoting interbody lumbar fusion after surgery.
ObjectiveTo explore the effectiveness and safety of treatment of thoracic tuberculosis with thoracoscope supported by digital technology. MethodsBetween June 2010 and February 2012, 11 patients with thoracic tuberculosis were treated and the clinical data were retrospectively analyzed. There were 7 males and 4 females with an average age of 23.6 years (range, 16-47 years) and an average disease duration of 16 months (range, 6-18 months). Two vertebral bodies and one intervertebral space were involved at T6-11. At preoperation, the neurologic function degree was classified as Frankel grade E. Three dimensional reconstruction of thorax and spine and surgical procedure design (including focal clearance, bone grafting, and screw fixation) were done at SUPERIMAGE workstation. Surgery procedures were conducted following the preoperative designs. ResultsThe operative procedures were consistent with preoperative designs. All of these operations were successfully performed. The mean time of operation was 146 minutes (range, 120-180 minutes); the mean blood loss was 120 mL (range, 100-150 mL); the mean indwelling time of closed thoracic drainage was 38 hours (range, 24-48 hours); and the mean hospitalization time was 4.6 days (range, 3-5 days). Eleven patients were followed up 12-25 months (mean, 16 months). No complication of nerve damage, incision pain and infection, or pulmonary infection was observed. Rigid fixation and born fusion were obtained at last follow-up; no obvious change of thoracic vertebral alignment was detected and no internal fixation failure occurred. ConclusionIt is a minimally invasive, effective, and safe method to treat thoracic tuberculosis with thoracoscope supported by digital technology.
ObjectiveTo summarize the research progress of the regulation effect of hypoxia inducible factor (HIF) on intervertebral disc. MethodsThe domestic and foreign related literature about the regulation effect of HIF on intervertebral disc was reviewed, summarized, and analyzed. ResultsHIF is a key transcription factor that is in response to hypoxia by cells, which is widely distributed in tissues and organs, including intervertebral disc. Hypoxia inducible factor is expressed highest in the nucleus pulposus which has the lowest oxygen concentration in the intervertebral disc. The effects of HIF include the regulation of nucleus pulposus differentiation and development, maintenance of the survival, energy metabolism, and anabolism of nucleus pulposus cells, and maintenance of the stability of extracellular matrix. ConclusionHIF plays a vital role in the development and differentiation of intervertebral disc and maintenance of physiological function, which may become a target for the research of the mechanism and the treatment of intervertebral disc degeneration.
ObjectiveTo review the current status and advances of in vivo nucleic acid del ivery mediated by poly(ethylenimine) (PEI). MethodsThe related home and abroad literature about nucleic acid del ivery with applications in cancer treatments and tissue engineering was extensively reviewed and analyzed. ResultsA variety of in vivo study on the potential of PEI-mediated nucleic acid del ivery has been carried out and made certain effects in the animal model, ranging from cancer treatments to rectification of physiological defects (eg. cranial defect and corneal epithelium defect). Tail vein injection is the most commonly adopted route of administration in vivo, followed by pulmonary administration and intralesional injection. However, transfection and expression in vivo have some shortcomings, such as low transfection efficiency and short expression time, so there are some limitation in the cl inical application. ConclusionPEI mediated nucleic acid del ivery provides a good method for cancer treatments and rectification of physiological defects. For future research, not only should more in vivo animal testing be done, but the procedures of experimentation also need to be standardized.
ObjectiveTo evaluate the effect of poly-amino acid/nano-hydroxyapatite/calcium sulfate (PHC) Cage in lumbar interbody fusion of the goat. MethodsEighteen mature female goats (weighing 29-33 kg) were divided into 3 groups randomly: PHC Cage group (group A), titanium Cage group (group B), and ilium group (group C). A left extraperitoneal approach was used to establish the animal model of discectomy and interbody fusion with Cage or ilium. The general situation was observed for 24 weeks after operation. X-ray films were taken to measure disc space height (DSH) before operation and at 4, 12, and 24 weeks after operation. CT three dimensional reconstuction was performed at 24 weeks after operation to evaluate the interbody fusion according to modified Brantigan grading. The specimens of L3, 4 were harvested for mechanical test, histological, and scanning electron microscope (SEM) observation at 24 weeks after operation. ResultsAll goats survived to the end of experiment. DSH at 4 weeks after operation increased when compared with preoperative one in each group, and then decreased;DSH was significantly lower at 12 and 24 weeks after operation than preoperative one in group C (P<0.05). There was no significant difference in DSH among 3 groups at preoperation and 4 weeks after operation (P>0.05);at 12 and 24 weeks after operation, DSH of groups A and B was significantly higher than that of group C (P<0.05), but no significant difference was found between groups A and B (P>0.05). CT three dimensional reconstuction showed that bony fusion was obtained in all goats of groups A and C, and in 3 goats of group B;according to modified Brantigan grading, the scores of groups A and C were significantlly higher than that of group B (P<0.05), but no significant difference between groups A and C (P>0.05). The biomechanical test showed that there was no significant difference in range of motion between group A and group B (P>0.05), which were significantly lower than that of group C (P<0.05). Microscopy and SEM observations showed that the interface between the Cage and vertebral body in group A was compact without obvious gap, and most conjunctive region was filled with osseous tissue;the interface was filled with soft tissue, and the connection was slack with obvious gap in some region in group B;the interface connection was compact, most region was filled with osseous tissue in group C. ConclusionThe interbody fusion with PHC Cage is effective in goat lumbar interbody fusion model. The interface connection is compact between the Cage and the host bone followed by micro-degradation of PHC Cage, but the long-term degradation need further observation.
ObjectiveTo summarize the experience in management of occult cerebrospinal fluid leakage (CSFL) in posterior thoracolumbar surgeries, and to explore the best drainage duration, as well as to analyse the ways to reduce the risk of CSFL. MethodsA retrospective analysis was made on the clinical data of 26 patients with occult CSFL in posterior thoracolumbar surgeries between January 2011 and January 2013. There were 15 males and 11 females, with the average age of 48.7 years (range, 36-59 years). Headache occurred in 19 cases, and 5 cases had nausea with 3 cases also having vomiting after operation. Drainage tube unobstructed and no CSFL from the skin incision were observed in 23 cases at the postoperative 2nd day, and the drainage pipe clamp test was performed at the 3rd day. Twenty-one patients had no CSFL and were given extubation; 2 cases having CSFL were given extubation after conservative treatments for 10 days. Three patients had CSFL with ineffective conservative treatments at the postoperative 2nd day, then received reoperation, incision suture, and drainage. At the postoperative 3rd day, if no CSFL was observed, these patients were given extubation and stayed in bed for 3-5 days. ResultsAll incisions healed and the healing time was 7-15 days (mean, 8 days). No incision infection, persistent CSFL, and other complications occurred. After extubation, headache, nausea, vomiting, and other symptoms were alleviated immediately. All patients were followed up 12-24 months (mean, 16 months). MRI at the postoperative 6th month showed no subcutaneous epidural pseudocyst. ConclusionThe quality of suturing is the key factor to prevent occult CSFL in posterior thoracolumbar surgery. Under the premise of good suture quality, extubation can be given at the postoperative 3rd day. Before extubation, the drainage pipe clamp test can be performed to make sure no CSFL and to reduce the risk of CSFL from the surgical incision after extubation.
ObjectiveTo observe the character of spino-pelvic sagittal alignment in patients with high-grade L5 isthmic spondylolisthesis, and to analyze the sagittal alignment alteration after operation. MethodBetween January 2009 and June 2014, 25 patients with high-grade L5 isthmic spondylolisthesis underwent posterior surgery, and the clinical data were retrospectively analyzed as study group. There were 14 males and 11 females with a mean age of 42.5 years (range, 20-65 years). The mean disease duration was 6 months (range, 3-12 months). According to the Meyerding evaluating system, 15 cases were rated as degree III, and 10 cases as degree IV. Eighty healthy adult volunteers were recruited simultaneously as control group. The lumbar sacral angle (LSA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), and sagittal vertical axis (SVA) were measured on preoperative and last follow-up standing full length lateral X-ray films. And these parameters were compared between study group (preoperative parameters) and control group. Then the patients in study group were divided into 2 subgroups according to Hresko's method:the balanced pelvis subgroup (n=14) and unbalanced pelvis subgroup (n=11) . The sagittal parameters were compared between 2 subgroups, and the alteration of sagittal parameters before surgery and at last follow-up was analyzed in each subgroup respectively. ResultsAll patients in study group were followed up 18 months on average (range, 6-48 months). After surgery, spondylolisthesis was reduced from degree III to degree 0 in 12 cases and to degree I in 3 cases, and from degree IV to degree 0 in 6 cases and to degree I in 4 cases. Bone fusion was obtained in all patients at last follow-up. The preoperative PI, SS, PT, and SVA of study group were significantly greater than those of control group (P<0.05) , while the TK was significantly smaller than that of control group (P<0.05) . In the balanced pelvis subgroup, LSA, LL, and SVA at last follow-up significantly decreased while TK significantly increased when compared with preoperative ones (P<0.05) . In the unbalanced pelvis subgroup, LSA, PT, and SVA at last follow-up significantly decreased while SS, LL, and TK significantly increased when compared with preoperative ones (P<0.05) . The preoperative LSA and PT in the unbalanced pelvis subgroup were significantly greater, while SS, LL, and TK were significantly smaller than those of balanced pelvis subgroup (P<0.05) ; while at last follow-up, significant differentce was found only in LSA between 2 subgroups (P<0.05) . ConclusionsThe LSA should be paid more attention in surgery to assure recovery of the sagittal balance because patients with high-grade L5 isthmic spondylolisthesis have greater PI, abnormal lumbosacral kyphosis, and sagittal imbalance.
ObjectiveTo observe the medium-term clinical and radiological outcomes of anterior release internal distraction in treatment of severe and rigid scoliosis. MethodsBetween March 2009 and March 2012, 26 patients with severe and rigid scoliosis were treated with anterior release, posterior internal distraction, and two stage posterior spinal fusion. There were 11 males and 15 females with an average age of 19.6 years (range, 14-25 years). The average disease duration was 13.6 years (range, 3-24 years). All cases were idiopathic scoliosis. Of 26 cases, 2 cases were rated as Lenke type I, 8 as type Ⅱ, 13 as type IV, 1 as type V, and 2 as type VI. The apical vertebrae located at T6 in 1 case, at T7 in 3 cases, at T8 in 7 cases, at T9 in 13 cases, and at T10 in 2 cases. The average 4 vertebral bodies were released by anterior approach, and average 14 vertebral bodies were fused after posterior surgery. Fourteen patients received 2 times distraction. Scoliosis Research Society-22 (SRS-22) questionnaire was used to access health-related quality of life. The radiological parameters were measured, including coronal plane Cobb angel of major curve, apical vertebral translation (AVT), C7 plumb line-center sacral vertical line (C7PL-CSVL), sagittal vertical axis (SVA), and thoracic kyphosis (TK) at pre-and post-operation. ResultsThe average total operation time was 592.7 minutes; the average total blood loss volume was 1 311.2 mL; and total hospitalization cost was (14.7±1.4)×104 yuan RMB. The coronal plane Cobb angle of major curve was (55.7±16.5)°, and the TK was (43.2±16.2)° after first distraction. The patients were followed up 2-5 years (mean, 3.8 years). Temporary dyspnea and pleural effusion occurred in 1 case respectively after distraction, and symptoms disappeared after symptomatic treatment. Screw loosening and pseudoarthrosis formation was observed in 1 case at 6 months after fusion, good recovery was achieved after revision. No infection or neurological complication was found. The coronal plane Cobb angel of major curve, TK, and AVT after fusion and at last follow-up were significantly lower than preoperative ones (P<0.05), but no significant difference was found between at post-fusion and last follow-up (P>0.05). There was no significant difference in C7PL-CSVL and SVA between at pre-and post-operation (P>0.05). At last follow-up, SRS-22 questionnaire scores were 4.32±0.42 for active degree, 4.54±0.58 for mental health, 3.97±0.76 for self-image, 4.09±0.64 for pain, and 4.03±0.83 for satisfaction degree. ConclusionAnterior release internal distraction can provide satisfactory correction results for severe and rigid scoliosis with higher safety and lower incidence of complication.
ObjectiveTo discuss the early effectiveness of polyaminoacid/nano-hydroxyapatite/calcium sulfate (PAA/HA/CS) Cage (PHC Cage) in lumbar fusion surgery. MethodsThirty cases undergoing lumbar fusion of single segment between March and September 2014 were enrolled in this study. The patients were randomly divided into the trial group (n=20) and the control group (n=10). The PHC Cage was implanted in the trial group, while the polyetheretherketone (PEEK) Cage was implanted in the control group. The patients of 2 groups mainly presented lumbocrural pain and lower limb radiation pain or numbness. There was no significant difference in gender, age, type, affected segment, disease duration, preoperative intervertebral height, the lordosis angle of fusion segments, and the Oswestry Disability Index (ODI) between 2 groups (P > 0.05). Lateral lumbar X-ray films and three dimensional CT were taken preoperatively and at 1 week and 3, 6, and 12 months postoperatively. The intervertebral height and the lordosis angle of fusion segments at 1 week and 3, 6, and 12 months after operation and ODI at 3, 6, and 12 months after operation were measured; and the bone graft fusion rate was evaluated according to Brantigan criteria. ResultsThere was no significant difference in operation time, intraoperative blood loss, and the amount of autologous blood transfusion between 2 groups (P > 0.05). Healing by first intention was obtained in 30 cases. All patients were followed up 12 months. The intervertebral height of fusion segments, the lordosis angle of fusion segments, and ODI at each time point after operation were significantly improved when compared with preoperative ones (P < 0.05). The ODI showed significant difference between 3 months and 6, 12 months (P < 0.05), but there was no significant difference between the other time points after operation (P > 0.05). There was no significant difference in the intervertebral height and the lordosis angle of fusion segments between groups at different time points (P > 0.05). There was no significant difference in the above indexes between the trial group and the control group at each time point (P > 0.05). At last follow-up, 5 cases were rated as Brantigan grade E, 13 cases as grade D, and 2 cases as grade C in the trial group; 4 cases were rated grade E, 5 cases as grade D, and 1 case as grade C in the control group. The bone fusion rate was 90% in 2 groups. ConclusionThe PHC Cage can effectively restore and maintain the disc height of fusion segment, normal sequence and biomechanical stability of the lumbar spine. The PHC Cage is similar to the PEEK Cage and has good clinical outcome in short-term follow-up.