To investigate the effects of postoperative fusion implantation on the mesoscopic biomechanical properties of vertebrae and bone tissue osteogenesis in idiopathic scoliosis, a macroscopic finite element model of the postoperative fusion device was developed, and a mesoscopic model of the bone unit was developed using the Saint Venant sub-model approach. To simulate human physiological conditions, the differences in biomechanical properties between macroscopic cortical bone and mesoscopic bone units under the same boundary conditions were studied, and the effects of fusion implantation on bone tissue growth at the mesoscopic scale were analyzed. The results showed that the stresses in the mesoscopic structure of the lumbar spine increased compared to the macroscopic structure, and the mesoscopic stress in this case is 2.606 to 5.958 times of the macroscopic stress; the stresses in the upper bone unit of the fusion device were greater than those in the lower part; the average stresses in the upper vertebral body end surfaces were ranked in the order of right, left, posterior and anterior; the stresses in the lower vertebral body were ranked in the order of left, posterior, right and anterior; and rotation was the condition with the greatest stress value in the bone unit. It is hypothesized that bone tissue osteogenesis is better on the upper face of the fusion than on the lower face, and that bone tissue growth rate on the upper face is in the order of right, left, posterior, and anterior; while on the lower face, it is in the order of left, posterior, right, and anterior; and that patients’ constant rotational movements after surgery is conducive to bone growth. The results of the study may provide a theoretical basis for the design of surgical protocols and optimization of fusion devices for idiopathic scoliosis.
ObjectiveTo summarize the progress of the surgical selection of fusion levels for degenerative scoliosis. MethodsThe domestic and foreign related literature about degenerative scoliosis, including clinical features, classification, surgical treatment, and the fused segment, was summarized. ResultsDegenerative scoliosis is very complicated. Short segment fusion and long segment fusion are the main surgical types. The long segment fusion is better in terms of reconstructing the stability of spine; however, it has more related complications. The short segment fusion has been used widely in clinical, but it causes degenerative disease easily. W/AL value can be used to direct the selection of short or long segment fusion for degenerative scoliosis. ConclusionThe key to success surgery is choosing reasonable fused segment. Now there is no unified selection standard. With more knowledge about degenerative scoliosis, greater development can be expected in the future.
ObjectiveTo review the recent progress in research on the role of estrogen and estrogen receptor on the onset and progression of adolescent idiopathic scoliosis (AIS). MethodsThe recently published clinical and experimental 1iterature at home and abroad on abnormality of estrogen and its receptor in AIS was reviewed and summarized. ResultsThere are many abnormal changes of estrogen and estrogen receptor in most AIS patients, including higher serum estrogen concentration, unusual cellular response to estrogen, late age at menarche, and gene polymorphisms of estrogen receptor, which are closely associated with AIS predisposition, curve severity, and scoliosis progression. ConclusionEstrogen and its receptor participate in the onset and progression of AIS by certain mechanisms, but exact mechanism remains indefinite, which needs further research to better define the role of estrogen and its receptor in AIS.
Objective To discuss operative strategies of posterior deformity vertebra resection and instrumentation fixation in the treatment of congenital scol iosis or kyphoscol iosis in child and adolescent patients, and to evaluate the surgicalresults. Methods From May 2003 to December 2007, 28 patients with congenital scol iosis or kyphoscol iosis were treatedwith one stage posterior deformity vertebra resection. There were 11 males and 17 females with an average age of 9.6 years (1.5-17.0 years). The locations were thoracic vertebra in 13 cases, thoracolumbar vertebra in 10 cases, and lumbar vertebra in 5 cases. All the patients underwent one stage posterior deformity vertebra resection, fusion and correction with pedicle instrumentation. According to different types of deformities, the patients underwent three different surgeries: hemivertebra resection (13 patients), hemivertebra resection combined contralateral unsegmental resection (7 patients), and total vertebral column resection (8 patients). Based on short or long segmental pedicle instrumentation, deformities were corrected and fixed, in 7 patients with short segmental fixation (group A), in 13 patients with long segmental fixation with hemivertebra resection or combined contralateral unsegmental resection (group B), and in 8 patients with long segmental fixation with total vertebral column resection (group C). The operative duration and the volume of blood loss were recorded, and the correction rate was calculated through measurement of Cobb angles of scol iosis and kyphosis before and after operation. Results The operation time of groups A, B, and C was (98 ± 17), (234 ± 42), and (383 ± 67) minutes, respectively, and the blood loss during operation was (330 ± 66), (1 540 ± 120), and (4 760 ± 135) mL, respectively; showing significant differences among three groups (P lt; 0.05). All patients achieved one-stage heal ing of incision. No deep infection, respiratory failure or deep vein thrombosis occurred. One patient had the signs of ischemical reperfusion injury of spinal cord 6 hours after operation and recovered after 2 weeks of relative therapy in group C; no neurological compl ication occurred in other patients. The mean follow-up period was 32.8 months (24-72 months). Intervertebral rigid fusion was identified from radiological data 6 months after operation according to contiguous callus crossed intervertebral gap and maintenance of correction results. No instrumentation failure occurred. There were significant differences in the Cobb angle between before and after operations (P lt; 0.01). There were significant differences in the corrective rate of scol iosis between groups A, B and group C (P lt; 0.05). Meanwhile, there were significant differences in the corrective rate of kyphosis between groups A, C and group B (P lt; 0.05). Conclusion One-stage posterior deformity vertebra resection has a good capabil ity of correcting congenital scol iosis or kyphoscol iosis on coronal and sagittal plane rel ied on removal deformity origin. It is important to select appropriated strategies on deformity resection and segmental fixation according to different ages and deformity situations of patient.
Objective To review the research progress of upper instrumented vertebra (UIV) selection strategy for long-segment fixation (LSF) in adult degenerative scoliosis (ADS). Methods The relevant domestic and foreign literature in recent years was reviewed, and the selection strategy of sagittal and coronal UIV for LSF in ADS patients, the relationship between UIV selection and proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), the impact of minimally invasive spine surgery on the selection strategy of UIV were summarized. Results LSF can restore the biomechanical balance of the spine and reconstruct the physiological curve of the spine for ADS patients. LSF should be selected for ADS patients with severe scoliosis, vertebral rotation, and severe sagittal imbalance. For patients with poor general condition, UIV can choose the thoracic and lumbar vertebrae to reduce the operation time and intraoperative bleeding, which is conducive to early mobilization and reduce complications; for patients with good general condition, the upper thoracic vertebrae can be considered if necessary, in order to achieve satisfactory long-term effectiveness. However, the lower thoracic vertebra (T9、10) should be selected as much as possible to reduce postoperative complications such as PJK and PJF. In recent years, a new reference marker, the first coronal reverse vertebra was proposed, to guide the selection of UIV. But a large-sample multicenter randomized controlled study is needed to further verify its reliability. Studies have shown that different races and different living habits would lead to different parameters of the spine and pelvis, which would affect the selection of UIV. Minimally invasive surgeries have achieved satisfactory results in the treatment of ADS, but the UIV selection strategy in specific applications needs to be further studied. Conclusion The selection strategy of UIV in LSF has not yet been unified. The selection of UIV in the sagittal plane of the upper thoracic spine, the lower thoracic spine, or the thoracolumbar spine should comprehensively consider the biomechanical balance of the spine and the general condition of the patient, as well as the relationship between the upper horizontal vertebra, the upper neutral vertebra, and the upper end vertebra on the coronal plane.
ObjectiveTo investigate the optimal surgical opportunity timing of posterior hemivertebra resection by comparing the outcomes of surgical treatment for congenital spinal deformity in patients at different ages. MethodsBetween January 2007 and Februay 2013, 36 cases of congenital hemivertebra scoliosis underwent one-stage posterior hemivertebra resection and segmental instrumentation fixation and fusion. There were 22 males and 14 females, with an average age of 16.8 years (range, 5-48 years). The patients were divided into 3 groups:group A (≤10 years, n=7), group B (10-20 years, n=22), and group C (>20 years, n=7). There was no significant difference in gender, segment, type, and complication among 3 groups (P>0.05). Anteroposterior and lateral X-ray films were taken before and after operation to measure the scoliosis Cobb angle, kyphosis Cobb angle, and C7 plumb line-center sacral vertical line (C7PL-CSVL). The improvement rate was calculated. And the perioperative and long-term complications were recorded. ResultsThe operation time of group A was significantly less than that of group C (P<0.05); the intraoperative blood loss of group B and group C were significantly more than that of group A (P<0.05); and the fixed segments of group B and group C were significantly more than those of group A (P<0.05). Thirty-six cases were followed up 7-62 months (mean, 31.3 months). No poor wound healing, pedicle cutting, pseudoarticulation formation, and other complications occurred during the follow-up. At last follow-up, 31 patients obtained a balance of double shoulders and double hips. The scoliosis Cobb angle, kyphosis Cobb angle, and C7PL-CSVL at immediate after operation and last follow-up were significantly improved when compared with preoperative ones in 3 groups (P<0.05). The scoliosis Cobb angle at last follow-up of group B was significantly larger than that of group C, the kyphotic correction rate at immediate after operation was significantly larger in groups A and C than in group B, the kyphotic correction rate of group B at last follow-up was significantly less than that of group C, and C7PL-CSVL correction rate of group A at immediate after operation was significantly larger than that of group B, all showing significant differences (P<0.05). ConclusionEarly one stage posterior hemivertebra resection is safe and effective, especially in patients who had no formation of structural compensatory bending and spinal stiffness, which can shorten the operation time and reduce the fixed segments and intraoperative hemorrhage. Influence on the growth and activity of the spine is relatively small.
Objective To further investigate the possible mechanism of the correction of scol iosis with Staple by quantifying the effect of Staple on growth rate of vertebral growth plates in goat scol iosis. Methods Experimental scol iosis was created in 10 juvenile female goats by using unilateral pedicle screws asymmetric tethering. After 8-10 weeks, goats were divided randomly into Staple treated group (n=5) and control group (n=5). All tethers were removed in both groups and Staplegroup underwent anterior vertebral stapl ing with 4-5 shape memory alloy Staples along the convexity of the maximal curvature after posterior tether being removed. All goats were observed for an additional 8-13 weeks, the Cobb angle were measured to observe the correction of scol iosis. The fluorochromes Oxytetracycl ine and Calcein were administered respectively 18 and 3 days before death to label the ossifying front under the growth plates. Superior intervertebral disc of apical vertebra and two adjacent growth plates were completely harvested in all goats. All specimens were embedded with polymethyl methacrylate and sl iced undecalcified. The growth rates of the vertebral growth plates were calculated by measuring the distance between the two fluorescent l ines with fluorescence microscope. Results Nine (5 in Staple treated group and 4 in control group) of 10 tethered goats had progressive scol iotic curves of significant magnitude after 8-10 weeks of tethering. In Staple treated group, the Cobb angles were (34.8 ± 12.4)° at the instant after treatment , and (15.6 ± 11.7)° 8-13 weeks after treatment; showing statistically significant difference (P lt; 0.05). In the control group, the Cobb angles were (49.3 ± 18.0)° at the instant after treatment, and(49.0 ± 17.6)° 8-13 weeks after treatment; showing no statistically significant difference (P gt; 0.05). In Staple treated group, the growth rate of growth plate in the concavity (3.27 ± 0.96) μm/d was higher than that in convexity (1.84 ± 0.52) μm/d (P lt; 0.05), while the growth rate of the concavity did not differ significantly from that of the convexity in control group (P gt; 0.05). Conclusion Staple can significantly alter the growth rates of two sides of vertebrae in scol iosis with the growth rate of concavity exceeding the one of convexity, which results in correction of deformity.
Objective To elucidate the new development and effects of three-dimensional correction techniques of idiopathic scol iosis (IS). Methods The related home and abroad l iterature concerning three-dimensional correction techniques of IS was extensively reviewed. Results With more and more attention to three-dimensional correction of IS, all kinds of surgery and developed techniques of correction are applied to the correction of IS. The effects of three-dimensional correction of IS are satisfied. Conclusion With more knowledge about IS and more developed theory of correction, more safe and effective techniques of correction is therefore the hot spot for future study.