The efficacy of bracing in the treatment of progressive early-onset scoliosis.

Serial casting as one of the applications to treat early-onset scoliosis has been reported efficiently to improve deformity, but no report has focused on the efficacy of braces in the treatment of congenital early-onset scoliosis and comparison with progressive idiopathic early-onset scoliosis. Patients with progressive EOS treated with braces in our institution with a minimum of 4 years follow-up were reviewed. Two groups according to the etiological diagnosis were analyzed and compared: the congenital scoliosis (CS) group and idiopathic scoliosis (IS) group. The success cases and the failure cases were also compared. 27 patients with an average main Cobb angle of 38.19° (20-55) underwent initial bracing at an average age of 55.7 months (24-108), the average follow-up time was 76.19 months (49-117). In IS group the main Cobb angle was corrected to 18.69 ± 12.06° (48.61%) following the first bracing; the final Cobb angle was 23.08 ± 22.15°(38.76%) after brace removal. In CS group the main Cobb angle was corrected to 33.93 ± 10.31°(17.1%) following the first bracing and 37.93 ± 14.74°(3.53%) after brace removal. Both coronal chest width and T1-T12 height increased dramatically from pre-bracing to the last follow-up. Patients diagnosed as IS tended to have a better result in main Cobb angle correction than that of CS (P = 0.049). By the time of last follow-up, 8 patients had undergone surgery, and the operation time was postponed by 68.88 ± 26.43 months. For patients with progressive early-onset scoliosis, bracing is an efficient nonsurgical alternative to casting, and some of them can be cured; if not, eventual surgical intervention can be delayed for a period of time without restrictions on the thoracic cavity.

Construction of the Adjusted Scoliosis 3D Finite Element Model and Biomechanical Analysis under Gravity.

OBJECTIVE: Adolescent idiopathic scoliosis (AIS) is a three-dimensional structural deformity of the spine caused by the disruption of the biomechanical balance of the spine. However, the current biomechanical modeling and analysis methods of scoliosis cannot really describe the real state of the spine. This study aims to propose a high-precision biomechanical modeling and analysis method that can reflect the spinal state under gravity and provide a theoretical basis for therapeutics. METHODS: Combining CT and X-ray images of AIS patients, this study constructed an adjusted three-dimensional model and FE model of the spine corresponding to the patient's gravity position, including vertebral bodies, intervertebral discs, ribs, costal cartilage, ligaments, and facet cartilage. Then, the displacement and stress of the spine under gravity were analyzed. RESULTS: A model of the T1-Sacrum with 1.7 million meshes was constructed. After adding the gravity condition, the maximum displacement point was at T1 of thoracic vertebra (20.4 mm). The analysis indicates that the stress on the lower surface of the vertebral body in thoracolumbar scoliosis tended to be locally concentrated, especially on the concave side of the primary curvature's vertebral body (the maximum stress on the lower surface of T9 is 32.33 MPa) and the convex side of the compensatory curvature's vertebral body (the maximum stress on the lower surface of L5 is 41.97 MPa). CONCLUSION: This study provides a high-precision modeling and analysis method for scoliosis with full consideration of gravity. The reliability of the method was verified based on patient data. This model can be used to analyze the biomechanical characteristics of patients in the treatment plan design stage.

Two-stage posterior-only procedures for correction of severe spinal deformities.

PURPOSE: To review the outcomes of surgical treatment for severe spinal deformities via a two-stage posterior-only approach. METHODS: A total of 18 patients with large and rigid spinal deformities were studied based on clinical and radiographic data. All of them received a two-stage posterior-only approach: first on the concave side by internal distraction of pedicle screws and rods through intramuscular tunnels, followed by respiratory function exercise and improving nutritional status during the intervening period, and finally by posterior additional correction, ultimate instrumentation and spinal fusion in the second operation. RESULTS: The mean major coronal curve was corrected by 46% after the first operation and by 60.4% after the second operation. The mean thoracic kyphosis was corrected by 50.9% after the first operation and by 64.8% after the second operation. The loss of correction mean was 3.3° for the major coronal curve and 2.6° for the thoracic kyphosis at a mean of 31.5 months follow-up. The mean operation time for the first and second operation was 186.2 and 300.6 min, and the mean intraoperative blood loss was 211.1 and 1,597.2 mL, respectively. No severe complication was noticed in this series. CONCLUSIONS: The two-stage posterior-only procedures permitting stepwise correction for the treatment of severe spinal deformities provide safe and satisfactory outcomes in this patient population.

[Analysis of neurological deficits complications in the treatment of spinal deformity with posterior spinal osteotomy].

OBJECTIVE: To investigate the incidence and causes of neurologic deficits complications in the treatment of spinal deformity with posterior spinal osteotomy. METHODS: From January 2007 to December 2010, 321 cases of scoliosis or kyphosis patients were treated with posterior spinal osteotomy. There were 124 male and 197 female with an average age of (19 ± 11) years (2 - 56 years). The average preoperative main Cobb angle was 108° ± 33° (48° - 175°), the average kyphotic angle was 74° ± 29° (53° - 170°) before operation. Pedicle subtraction osteotomy was used in 226 cases, 95 cases with vertebral column resection. Pedicle screw-rod system was used for fixation. The patients were monitored by Somatosensory-evoked potentials monitoring and Stagnara wake-up test. RESULTS: There were 11 cases with varying degrees of new neurologic deficits and the total incidence was 3.4%. The causes were as followed, spinal translation in 2 cases, compromised by close of resected areas in 2 cases, residual bone compression in 1 case, inadvertent operation in 2 cases, screw malposition in 1 case, hematoma compression in 1 case and spine elongation in 2 cases. There was significant difference between the patients with preexisting neurologic deficits (20.0%) and the patients with intact neurologic function (2.6%) (χ(2) = 13.060, P = 0.011), no significant differences in different classes of the age, etiology, deformity, osteotomy type and surgical type (P > 0.05). But the incidence of neurologic deficits was 4.6% in congenital scoliosis, 7.1% in neuromuscular scoliosis, 5.1% in kyphosis, 5.9% in adult deformity and 5.9% in Cobb angle more than 100°, which was higher than other classes. All the 11 cases were given emergent Methylprednisolone, neurotrophic drugs and hyperbaric oxygen therapy, 4 cases were underwent surgical exploration again. After treatment, 7 cases recovered completely, 2 cases recovered partially and 2 cases failed to improve at the last follow-up. CONCLUSIONS: Severe spinal deformity could be effectively treated with posterior spinal osteotomy. But the procedure is technical demanding and risky for neurologic deficits. The high risk factor is preexisting neurologic deficits.

Current understanding of tandem spinal stenosis: epidemiology, diagnosis, and surgical strategy.

Tandem spinal stenosis (TSS) is defined as the concomitant occurrence of stenosis in at least two or more distinct regions (cervical, thoracic, or lumbar) of the spine and may present with a constellation of signs and symptoms. It has four subtypes, including cervico-lumbar, cervico-thoracic, thoraco-lumbar, and cervico-thoraco-lumbar TSS. The prevalence of TSS varies depending on the different subtypes and cohorts. The main aetiologies of TSS are spinal degenerative changes and heterotopic ossification, and patients with developmental spinal stenosis, ligament ossification, and spinal stenosis at any region are at an increased risk of developing TSS. The diagnosis of TSS is challenging. The clinical presentation of TSS could be complex, concealed, or severe, and these features may be confusing to clinicians, resulting in an incomplete or delayed diagnosis. Additionally, a consolidated diagnostic criterion for TSS is urgently required to improve consistency across studies and form a basis for establishing treatment guidelines. The optimal treatment option for TSS is still under debate; areas of controversies include choice of the decompression range, choice between simultaneous or staged surgical patterns, and the order of the surgeries. The present study reviews publications on TSS, consolidates current awareness on prevalence, aetiologies, potential risk factors, diagnostic dilemmas and criteria, and surgical strategies based on TSS subtypes. This is the first review to include thoracic spinal stenosis as a candidate disorder in TSS and aims at providing the readers with a comprehensive overview of TSS.

Surgical outcomes in children under 10 years old in the treatment of congenital scoliosis due to single nonincarcerated thoracolumbar hemivertebra: according to the age at surgery.

PURPOSE: Hemivertebra is one of the common pathogenesis of congenital scoliosis. The timing of operation is undefined. Our study compared the surgical outcomes in children under age 10 years with scoliosis due to single nonincarcerated thoracolumbar hemivertebra according to the age at surgery. METHODS: From January 2009 to August 2017, we retrospectively investigated 34 consecutive cases of congenital scoliosis treated by posterior hemivertebra resection and fusion with pedicle screw fixation. All cases were divided into two groups according to the age at surgery and followed-up for at least 2 years, group 1 (≤ 5 years old), and group 2 (5 to 10 years old). RESULTS: The mean Cobb angle of the main curve was improved from 48.58° to 15.53° (68.05%) in group 1, and from 43.73° to 11.33° (75.43%) in group 2. The segmental curve was improved from 44.16° to 11.53° (74.64%) in group 1, and the segmental curve was consistent with the main curve in group 2. The mean segmental kyphosis was improved from 27.50° to 8.42° (67.40%) in group 1, and from 29.00° to 5.00° (84.73%) in group 2. Five patients developed distal adding-on, and four patients were found proximal junctional kyphosis during the follow-up. CONCLUSION: Not all the deformities caused by single nonincarcerated thoracolumbar hemivertebra would progress greatly with the spinal growth. No significant statistical differences were found in the coronal and sagittal correction rate between the two groups. A limited delayed surgery after 5 years but before 10 years of age with close follow-up can achieve satisfied results.

Nox4 Promotes RANKL-Induced Autophagy and Osteoclastogenesis via Activating ROS/PERK/eIF-2α/ATF4 Pathway.

Receptor activator of nuclear factor-κB ligand (RANKL) has been found to induce osteoclastogenesis and bone resorption. However, the underlying molecular mechanisms remain unclear. Via conducting a series of biochemical experiments with in vitro cell lines, this study investigated the role and mechanism of NADPH oxidase 4 (Nox4) in RANKL-induced autophagy and osteoclastogenesis. In the current study, we found that RANKL dramatically induced autophagy and osteoclastogenesis, inhibition of autophagy with chloroquine (CQ) markedly attenuates RANKL-induced osteoclastogenesis. Interestingly, we found that the protein level of Nox4 was remarkably upregulated by RANKL treatment. Inhibition of Nox4 by 5-O-methyl quercetin or knockdown of Nox4 with specific shRNA markedly attenuated RANKL-induced autophagy and osteoclastogenesis. Furthermore, we found that Nox4 stimulated the production of nonmitochondrial reactive oxygen species (ROS), activating the critical unfolded protein response (UPR)-related signaling pathway PERK/eIF-2α/ATF4, leading to RANKL-induced autophagy and osteoclastogenesis. Blocking the activation of PERK/eIF-2α/ATF4 signaling pathway either by Nox4 shRNA, ROS scavenger (NAC) or PERK inhibitor (GSK2606414) significantly inhibited autophagy during RANKL-induced osteoclastogenesis. Collectively, this study reveals that Nox4 promotes RANKL-induced autophagy and osteoclastogenesis via activating ROS/PERK/eIF-2α/ATF4 pathway, suggesting that the pathway may be a novel potential therapeutic target for osteoclastogenesis-related disease.

[Clinical application of posterior paramedian approach in low back surgeries].

OBJECTIVE: To prospectively evaluate the clinical effects of posterior paramedian approach in nerve root decompression and reducing muscle damage in low back surgeries. METHODS: Study group included 30 cases treated from January 2007 to May 2008, DDD 8 cases, spondylolisthesis 6 cases, LDH 11 cases, Low back surgery failure re-operation 5 cases. Based on the comprehensive understanding of modern spine anatomy, we abandoned laminectomy in our procedure, applied a mid-waist skin incision, dissect to the paraspinal muscles where you could easily reach the facets by separating between the multifidus and longissimus, enlarge the canal by performing resection along ligamentum flavum and the inner broader of the articular process, remove enough tissue till you could expose the traversing root and the disc space, this method could achieve a limited but precise and effective decompression with not taking out all of the articular process. Once the anatomy mark of the pedicle is located (usually would be at the central area of the incision), pedicle screws placement would be precise and easy without struggling with muscle traction. The following procedures would be Spondylolisthesis reduction, discectomy and interbody fusion. RESULTS: Post-op patients of study group all showed significant improvement of pain symptoms, VAS reduced from 7.14 + or - 1.8, pre-op to 1.39 + or - 0.72 post-op, narrowed disc space regained height, spondylolisthesis reached anatomic reduction, no complications such as pedicle screw misplacement and nerve root damage were found, the lumbar spine regained it's physiological lordosis structure. Significant difference is discovered (P < 0.001) in statistic study concerning the rate of intractable low back pain between pre-op and post-op. CONCLUSIONS: Applying low back surgery through posterior para-median approach could directly reach the inferior/superior facets and the "soft" structures of the spinal canal, expose the exact decompression region and anatomy mark of the pedicle in the central surgical field without strong retraction on the para-spinal muscles. This approach has the advantage of lowering the surgical difficulty of implantation, reducing the risk of nerve damage and is also a minimum invasive procedure. In many cases, laminectomy is unnecessary, leaving the lamina intact could preserve the physiological anatomy of the spine.

Posterior-only vertebral column resection for revision surgery in post-laminectomy rotokyphoscoliosis associated with late-onset paraplegia: A case report and literature review.

RATIONALE: Severe post-laminectomy spinal deformity associated with late-onset paraplegia is a complex and rare disorder. Little is known about revision surgery in post-laminectomy rotokyphoscoliosis associated with late-onset paraplegia treated by the single stage posterior-only vertebral column resection (VCR) procedure. PATIENT CONCERNS AND DIAGNOSES: The patient was a 14-year-old male diagnosed as post-laminectomy rotokyphoscoliosis associated with late-onset paraplegia. He underwent posterior total laminectomy through the thoracic spine for intramedullary spinal cord tumors at the age of 3 years in another hospital. He then developed kyphosis deformity 1 year after laminectomy, and underwent posterior spinal fusion without instrumentation at 9 years of age. However, the deformity gradually progressed over the years. Seven months before admission to our hospital, he developed a significant progression of neurological deficits, including weakness of strength and sensation in lower extremities bilaterally, with no bladder or bowel dysfunction. There was no improvement of spinal cord function with conservative measures, and he required a wheelchair for movement. INTERVENTIONS: The patient underwent posterior-only VCR by single stage with the purposes of spinal cord decompression and spinal deformity correction. OUTCOMES: Postoperatively, he was transferred to the intensive care unit (ICU) and required positive pressure ventilation support to improve his respiratory condition. The child experienced cerebrospinal fluid leak (CSF) which resulted in an unplanned return to the operating room. The neurological function improved from preoperative Frankel C to Frankel D within 12 months of surgery, and recovered completely to Frankel E by 18 months. At the 24 month follow-up, the good neurological function was maintained; pulmonary function tests (PFTs) revealed improved forced vital capacity (FVC) and forced expiratory volume for 1 second (FEV1). The patient's coronal major curve and sagittal kyphosis were corrected from 70° to 21°, and 170° to 75°, respectively. LESSONS: These findings demonstrated that single-stage posterior-only VCR is efficacious but challenging for revision surgery in post-laminectomy rotokyphoscoliosis associated with late-onset paraplegia.

[Kyphoplasty for treatment of non-osteoporotic thoracolumbar compressive fractures: analysis of 17 cases].

OBJECTIVE: To evaluate the efficacy and safety of kyphoplasty for treatment of non-osteoporotic compressive fractures of thoracolumbar vertebrae. METHODS: Seven patients of non-osteoporotic thoracolumbar compressive fractures confirmed by plain X-ray examination and CT scanning, 14 males and 3 females, aged 35.2, all suffering from one level fracture, at T9 in 1 case, T11 in 2 cases, T12 in 7 cases, L1 in 5 cases, L2 in 1 case, and L3 in 1 case were. treated with percutaneous kyphoplasty. Under local anesthesia Kypho-X vertebra expander was inserted into the vertebral body and polymethylmethacrylate (PMMA) bone cement was filled. Then the patients were followed up for 6 months (6-24 months) by using the visual analog scale, Oswestry disability index (ODI), and the vertebra height and kyphosis were analyzed. RESULTS: All patients underwent the procedure safely. Except for two cases with complication of para-vertebra cement leakage no other complication occurred. The average surgery time was 55 min. All patients became able to get up of bed 2 days and discharged 7 days postoperatively and continued to be protected by hard prosthesis for two weeks more. The average score of VAS was 8.7 before the operation, and then gradually decreased, to 3.2 and 2.7 1 and 4 weeks postoperatively, and became 2.1 at the last follow-up (all P < 0.05). The average ODI score was 72.3 before the operation, and then gradually decreased to 48.6 and 28.9 1 week and 4 weeks postoperatively, and became 22.4 at the last follow-up (all P < 0.05). The average height of the vertebra was 14.3 mm preoperatively, and increased to 24.7 mm 1 week postoperative and 22.4 mm at the last follow up (both P < 0.05). The kyphosis of the fractured vertebra was 31.1 degrees preoperatively and decreased to 9.6 degrees 1 week postoperatively and 10.9 degrees at the last follow up (both P < 0.05). All patients returned to their previous work and life within 2 months postoperatively. CONCLUSION: Percutaneous kyphoplasty is effective and safe in the treatment of non-osteoporotic thoracolumbar compressive fractures with the advantages of minimum invasiveness, fast pain relief and recovery, as well as restoration of vertebra height and correction of kyphosis.

Spontaneous Improvement of Compensatory Knee Flexion After Surgical Correction of Mismatch Between Pelvic Incidence and Lumbar Lordosis.

STUDY DESIGN: A retrospective study. OBJECTIVE: The aim of this study was to investigate the correlation between pelvic incidence (PI) and lumbar lordosis (LL) mismatch and knee flexion during standing in patients with lumbar degenerative diseases and to examine the effects of surgical correction of the PI-LL mismatch on knee flexion. SUMMARY OF BACKGROUND DATA: Only several studies focused on knee flexion as a compensatory mechanism of the PI-LL mismatch. Little information is currently available on the effects of lumbar correction on knee flexion in patients with the PI-LL mismatch. METHODS: A group of patients with lumbar degenerative diseases were divided into PI-LL match group (PI-LL ≤ 10°) and PI-LL mismatch group (PI-LL > 10°). A series of radiographic parameters and knee flexion angle (KFA) were compared between the two groups. The PI-LL mismatch group was further subdivided into operative and nonoperative group. The changes in KFA with PI-LL were examined. RESULTS: The PI-LL mismatch group exhibited significantly greater sagittal vertical axis (SVA), pelvic tilt (PT) and KFA, and smaller LL, thoracic kyphosis (TK), and sacral slope than the PI-LL match group. PI-LL, LL, PI, SVA, and PT were significantly correlated with KFA in the PI-LL mismatch group. From baseline to 6-month follow-up, all variables were significantly different in the operative group with the exception of PI, although there was no significant difference in any variable in the nonoperative group. The magnitude of surgical correction in the PI-LL mismatch was significantly correlated with the degree of spontaneous changes in KFA, PT, and TK. CONCLUSION: The PI-LL mismatch would contribute to compensatory knee flexion during standing in patients with lumbar degenerative disease. Surgical correction of the PI-LL mismatch could lead to a spontaneous improvement of compensatory knee flexion. The degree of improvement in knee flexion depends in part on the amount of correction in the PI-LL mismatch. LEVEL OF EVIDENCE: 3.

Posterior Vertebral Column Resection for Severe and Rigid Spinal Deformity Associated With Neurological Deficit After Implant Removal Following Posterior Instrumented Fusion: A Case Report and Literature Review.

STUDY DESIGN: Case report. OBJECTIVE: To investigate the safety and efficacy of posterior vertebral column resection for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion. SUMMARY OF BACKGROUND DATA: Loss of correction after implant removal in patients with posterior instrumented fusion has been previously reported. However, to our knowledge, posterior vertebral column resection (PVCR) for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion has not been reported. METHODS: An 18-year-old female with severe and rigid spinal deformity associated with neurological deficit was classified as Frankel C, according to the Frankel grading system. She underwent posterior spinal fusion with pedicle screw fixation at 16 years, and her implants were removed after 1 year due to back pain. Seven months after removal of the implants, she began to experience weakness in her lower limbs but did not seek any treatment. She was unable to stand and had to use a wheelchair. The patient successfully underwent PVCR and posterior reinstrumentation. Within 3 months, her neurological status improved to Frankel E. RESULTS: The patient had no neurological deterioration and infections. There was no instrumentation failure and loosening correction at the 32 months follow-up. CONCLUSION: Our results suggest that PVCR and pedicle screw fixation is a safe and efficacious option for severe and rigid spinal deformity associated with neurological deficit after implant removal following posterior instrumented fusion. LEVEL OF EVIDENCE: N/A.

Bovine collagen peptides compounds promote the proliferation and differentiation of MC3T3-E1 pre-osteoblasts.

OBJECTIVE: Collagen peptides (CP) compounds, as bone health supplements, are known to play a role in the treatment of osteoporosis. However, the molecular mechanisms of this process remain unclear. This study aimed to investigate the effects of bovine CP compounds on the proliferation and differentiation of MC3T3-E1 cells. METHODS: Mouse pre-osteoblast cell line MC3T3-E1 subclone 4 cells were treated with bovine CP compounds. Cell proliferation was analyzed by MTT assays and the cell cycle was evaluated by flow cytometry scanning. Furthermore, MC3T3-E1 cell differentiation was analyzed at the RNA level by real-time PCR and at the protein level by western blot analysis for runt-related transcription factor 2 (Runx2), a colorimetric p-nitrophenyl phosphate assay for alkaline phosphatase (ALP), and ELISA for osteocalcin (OC). Finally, alizarin red staining for mineralization was measured using Image Software Pro Plus 6.0. RESULTS: Cell proliferation was very efficient after treatment with different concentrations of bovine CP compounds, and the best concentration was 3 mg/mL. Bovine CP compounds significantly increased the percentage of MC3T3-E1 cells in G2/S phase. Runx2 expression, ALP activity, and OC production were significantly increased after treatment with bovine CP compounds for 7 or 14 days. Quantitative analyses with alizarin red staining showed significantly increased mineralization of MC3T3-E1 cells after treatment with bovine CP compounds for 14 or 21 days. CONCLUSIONS: Bovine CP compounds increased osteoblast proliferation, and played positive roles in osteoblast differentiation and mineralized bone matrix formation. Taking all the experiments together, our study indicates a molecular mechanism for the potential treatment of osteoarthritis and osteoporosis.

The efficacy and cost-effectiveness of cell saver use in instrumented posterior correction and fusion surgery for scoliosis in school-aged children and adolescents.

Posterior spinal instrumentation and fusion surgery in school-aged children and adolescents is associated with the potential for massive intraoperative blood loss, which requires significant allogeneic blood transfusion. Until now, the intraoperative use of the cell saver has been extensively adopted; however, its efficacy and cost-effectiveness have not been well established. Therefore, the aim of this study is to determine the efficacy and cost-effectiveness of intraoperative cell saver use. This study was a single-center, retrospective study of 247 school-aged and adolescent patients who underwent posterior spinal instrumentation and fusion surgery between August 2007 and June 2013. A cell saver was used intraoperatively in 67 patients and was not used in 180 patients. Matched case-control pairs were selected using a propensity score to balance potential confounders in baseline characteristics. Allogeneic red blood cell (RBC) and plasma transfusions as well as blood transfusion costs were analyzed. The propensity score matching produced 60 matched pairs. Compared to the control group, the cell saver group had significantly fewer intraoperative allogeneic RBC transfusions (P = 0.012). However, when the combined postoperative and total perioperative periods were evaluated for the use of allogeneic RBC transfusion, no significant differences were observed between the two groups (P = 0.813 and P = 0.101, respectively). With regard to the total cost of perioperative transfusion of all blood products (RBC and plasma), costs for the control group were slightly lower than those of the cell saver group, but this variance did not reach statistical significance (P = 0.095). The use of the cell saver in posterior spinal instrumentation and fusion surgery in school-aged children and adolescents was able to decrease the amount of intraoperative allogeneic RBC transfusion but failed to decrease total perioperative allogeneic RBC transfusion. Moreover, the use of the cell saver was not cost-effective.

CT morphometric analysis to determine the anatomical basis for the use of transpedicular screws during reconstruction and fixations of anterior cervical vertebrae.

BACKGROUND: Accurate placement of pedicle screw during Anterior Transpedicular Screw fixation (ATPS) in cervical spine depends on accurate anatomical knowledge of the vertebrae. However, little is known of the morphometric characteristics of cervical vertebrae in Chinese population. METHODS: Three-dimensional reconstructions of CT images were performed for 80 cases. The anatomic data and screw fixation parameters for ATPS fixation were measured using the Mimics software. FINDINGS: The overall mean OPW, OPH and PAL ranged from 5.81 to 7.49 mm, 7.77 to 8.69 mm, and 33.40 to 31.13 mm separately, and SPA was 93.54 to 109.36 degrees from C3 to C6, 104.99 degrees at C7, whereas, 49.00 to 32.26 degrees from C4 to C7, 46.79 degrees at C3 (TPA). Dl/rSIP had an increasing trend away from upper endplate with mean value from 1.87 to 5.83 mm. Dl/rTIP was located at the lateral portion of the anterior cortex of vertebrae for C3 to C5 and ipsilateral for C6 to C7 with mean value from -2.70 to -3.00 mm, and 0.17 to 3.18 mm. The entrance points for pedicular screw insertion for C3 to C5 and C6 to C7 were recommended -2∼-3 mm and 0-4 mm from the median sagittal plane, respectively, 1-4 mm and 5-6 mm from the upper endplate, with TPA being 46.79-49.00 degrees and 40.89-32.26 degrees, respectively, and SPA being 93.54-106.69 degrees and 109.36-104.99 degrees, respectively. The pedicle screw insertion diameter was recommended 3.5 mm (C3 and C4), 4.0 mm (C5 to C7), and the pedicle axial length was 21-24 mm for C3 to C7 for both genders. However, the ATPS insertion in C3 should be individualized given its relatively small anatomical dimensions. CONCLUSIONS: The data provided a morphometric basis for the ATPS fixation technique in lower cervical fixation. It will help in preoperative planning and execution of this surgery.

Surgical treatment of severe scoliosis and kyphoscoliosis by stages.

BACKGROUND: Although previous reports had reported the use of temporary internal distraction as an aid to correct severe scoliosis, two-stage surgery strategy (less invasive internal distraction followed by posterior correction and instrumentation) has never been reported in the treatment of patients with severe spinal deformity. This study aimed to report the results of the surgical treatment of severe scoliosis and kyphoscoliosis by two-stage and analyse the safety and efficacy of this surgical strategy in the treatment of severe spinal deformities. METHODS: A total of 15 patients with severe scoliosis, kyphoscoliosis or kyphosis who underwent two-stage surgeries (less invasive internal distraction followed by posterior correction and instrumentation) were studied based on hospital records. Pretreatment radiographs and radiographs taken after first surgery (internal distraction by two small incisions), before second surgery (posterior correction, instrumentation and fusion), one week after second surgery and final follow-up were measured. Subjects were analyzed by age, gender, major coronal curve magnitude, flexibility of major curve, major sagittal curve magnitude before first surgery, after first surgery, before second surgery, after second surgery and at final follow-up. Complications related to two-stage surgeries were noted in each case. RESULTS: The average major curve magnitude was 129.4° (range, 95° to 175°), reduced 58.9° or 45.4% after first stage surgery and reduced 30.6° or 24.6% after second stage surgery. The loss of correction during the interval between two surgeries was 7.1%. The total major coronal curve correction was 81.4° or 62.9%. At the final follow up, the average loss of correction of major coronal curve was 3.9° and the final average correction rate was 59.7%. The average major sagittal curve magnitude was 80.3° (range, 30° to 170°), and the total major sagittal curve correction was 48.2°. Loss of correction averaged 4.0° for major sagittal curve and the final correction averaged 42.2°. Clinical complications were noted in the peri-operative and long-term periods. CONCLUSIONS: Two-stage surgery was a safe and effective surgical strategy in this difficult population. Using two-small-incision technique, the first stage surgery was less invasive. No permanent neurologic deficit was noted in this series.

[Balloon inflating and cement filling for treatment of avascular necrosis of the femoral head: a three-dimensional infinite-element study].

OBJECTIVE: To evaluate the biomechanical changes of balloon inflating and cement filling in avascular necrosis of the femoral head using finite-element analysis. METHODS: The procedure of percutaneous balloon inflating and cement filling was simulated in fresh specimen of human femoral head. CT scan and three-dimensional reconstruction were used to establish the three-dimensional model of the femoral head. The physiological load was analyzed using three-dimensional finite element model to simulate the load and calculate stress on the hip during walking. Finite element analysis was performed on the avascular necrosis model and balloon inflating and bone cement filling model to measure the Von-Mises force at the top, neck and weight-bearing area of the femoral head. Another 8 fresh specimens of femoral head necrosis of human were obtained to stimulate balloon inflating and bone cement filling procedures, and the displacement of the femoral head under different loads was recorded before and after the procedures. RESULTS: After bone cement filling in the necrosis area, the load reduced significantly in the weight-bearing area of the femoral head, and the load distribution became more uniform at the femoral neck and the top of the head. The anti-deformation ability of the necrosis femoral head increased after bone cement filling. The infinite-element analysis and specimen biomedical test showed similar results. CONCLUSION: Percutaneous balloon inflating and bone cement filling in the necrosis area can change the biomechanics mechanism of the femoral head and neck, improve the supporting capacity under load, and prevent the progression of head collapse.

[Experimental study of novel injectable nucleus pulposus prostheses implant].

OBJECTIVE: To explore the histological and the hematological change of rabbits after implanting novel injectable artificial nucleus prostheses, and to evaluate the biological safety. METHODS: In accordance with Biological Evaluation of Medical Devices, materials of polyurethane, silicone rubber and macromolecular polyethylene for medical use were made into short column 1 cm in length and 0.3 cm in diameter. Forty-eight SPF New Zealand white rabbits weighing 2.5-3.0 kg were used, and cavity 1 cm in depth was made in the area 2 cm away from the spinal midline by separating muscle. Then according to different material being implanted, the rabbits were divided into 3 groups (n = 16): Group A, polyurethane; group B, silicone rubber; group C, macromolecular polyethylene for medical use as negative control. General condition of the rabbits was observed after operation. Gross and histology observation were conducted 1, 4, 12 and 26 weeks after operation. Blood routine, biochemical function and electrolyte assays were performed 26 weeks after operation to observe pathological changes of organs. Meanwhile, physicochemical properties of the materials were detected, and the material in the same batch was used as negative control. RESULTS: All rabbits survived until the end of experiment, and all wounds healed by first intention. In each group, red swollen muscles were observed 1 week after operation and disappeared 4 weeks after operation, connective tissue around the implanted materials occurred 12 and 26 weeks after operation. At 26 weeks after operation, there were no significant differences among three groups in blood routine, biochemical function and electrolyte assays (P > 0.05). Organs had smooth surface without ulceration, ecchymosis, obvious swelling, hyperemia or bleeding, and nodules. There were no significant differences among three groups in percentage weight of each organ (P > 0.05). Histology observation: granulation tissue proliferation and inflammatory cell infiltration were observed in each group 1 week after operation, fibrous capsule formation around the materials and the disappearance of inflammatory cell infiltration were evident 4 weeks after operation, cyst wall grew over time and achieved stability 12 weeks after operation. The inflammatory response and the fiber cyst cavity of groups A and B met the standard of GB/T 16175 and were in line with group C. No specific pathological changes were discovered in the organs 26 weeks after operation. For group A, no significant difference was evident between before and after material implantation in terms of weight average molecular weight, number average molecular weight, tensile strength at break and elongation at break (P > 0.05). For group B, no significant difference was evident between before and after material implantation in shore hardness (P > 0.05). CONCLUSION: Novel injectable nucleus pulposus prostheses do not damage local tissue and function of organs, but provide good biocompatibility and biological safety.