A new method for calculating the desired laminoplasty opening size based on the target sagittal canal diameter before single-door cervical laminoplasty.

PURPOSE: To build a mathematical model which could calculate the desired laminoplasty opening size (LOS) based on the target sagittal canal diameter (SCD) before single-door cervical laminoplasty (SDCL) when taking the effects of surgery drill into consideration. METHODS: The model was based on geometric analysis on deformation of spinal canal; the formula was derived and characterized as: y (mm) = 2 [Formula: see text] × sin(ß/2) = c - d (y is the size of LOS, [Formula: see text] the size of transverse canal diameter, ß the size of laminoplasty opening size, c the size of mini-plate and d the diameter of the drill bit used during the surgery operation). The parameters of pre- and postoperative computed tomography scans of 20 patients who had undergone SDCL were measured by the picture archiving and communication system (PACS) software and a new instrument named as Lei's ruler, respectively. RESULTS: The effects of surgery SDCL were very significant; for each patient, the SCD was enlarged dramatically after the surgery (P < 0.01). The differences between the data obtained by PACS and Lei's ruler were no statistically significant (P > 0.05). According to the derived formula, the 95% confidence intervals of SCD after the surgery were within the range of 14 mm and 14.5 mm. CONCLUSION: Applying the mathematical model and derived formula, the desired LOS could be calculated according to the target SCD which could help the surgeon select an optimum mini-plate before SDCL. At the same time, a new measuring device named Lei's ruler is designed for the convenience of the derived formula. These slides can be retrieved under Electronic Supplementary Material.

Osteosarcoma in the coracoid process that mimicked an osteochondroma: A case report.

RATIONALE: Osteosarcomas are the most common primary malignant bone tumors in children and young adults; these tumors often affect the metaphyses of long bones such as the proximal humerus, proximal tibia, and distal femur. In contrast, osteosarcoma of the coracoid process is extremely rare. PATIENT CONCERNS: Herein, we describe a case of osteosarcoma affecting the coracoid process in a 40-year-old woman. The patient presented with shoulder pain, weakness, and an inability to raise her left arm. She had no previous record of shoulder injury and no significant family history. DIAGNOSES: Her C-reactive protein levels were normal, whereas her erythrocyte sedimentation rate and alkaline phosphatase levels were elevated. Imaging studies led to the initial diagnosis of osteochondroma. INTERVENTION: The patient underwent surgical resection. However, the postoperative pathological results revealed an osteosarcoma. The patient transferred to another hospital for subsequent treatment, and her outcome is unknown. LESSONS: A misdiagnosis or inadequate and/or delayed treatment for a coracoid process osteosarcoma could have grave consequences. Computed tomography and magnetic resonance imaging are essential for a diagnosis, and a biopsy can effectively confirm the diagnosis. Our findings suggest that considering only a single factor, or using incomplete information, can lead to an arbitrary diagnosis.

Aspirin inhibits osteoclastogenesis by suppressing the activation of NF-κB and MAPKs in RANKL-induced RAW264.7 cells.

Aspirin is a commonly used medicine as an effective antipyretic, analgesic and anti-inflammatory drug. Previous studies have demonstrated its potential effects of anti-postmenopausal osteoporosis, while the molecular mechanisms remain unclear. The effects of aspirin on receptor­activator of nuclear factor κB (NF­κB) ligand (RANKL)­induced osteoclasts were investigated in RAW264.7 cells in the current study. Using tartrate­resistant acid phosphatase (TRAP) staining, it was observed that aspirin inhibited the differentiation of RANKL­induced RAW264.7 cells. The mRNA expression of osteoclastic marker genes, including cathepsin K, TRAP, matrix metalloproteinase 9 and calcitonin receptor, were suppressed by aspirin as identified using reverse transcription­quantitative polymerase chain reaction analysis. The immunofluorescence assay indicated that aspirin markedly inhibited NF­κB p65 translocation to the nucleus in RANKL­induced RAW264.7 cells. In addition, aspirin also suppressed the phosphorylation of mitogen­activated protein kinases (MAPKs), observed by western blot analysis. Taken together, these data identified that aspirin inhibits osteoclastogenesis by suppressing the activation of NF­κB and MAPKs in RANKL­induced RAW264.7 cells, implying that aspirin may possess therapeutic potential for use in the prevention and treatment of osteoporosis.

A novel total cervical prosthesis for single-level cervical subtotal corpectomy: radiologic and histomorphometric analysis in a caprine model.

STUDY DESIGN: A novel total cervical prosthesis (TCP) for single-level cervical subtotal corpectomy was assessed in a caprine animal model. OBJECTIVES: To investigate the radiologic and histomorphometric characteristics of a novel TCP for single-level cervical subtotal corpectomy. SUMMARY OF BACKGROUND: Cervical disk replacement has emerged as a promising alternative to arthrodesis in the management of cervical disk herniation. However, they are designed for anterior cervical discectomy, and not suitable for cervical subtotal corpectomy. To solve this problem, our group has developed a novel TCP for single-level cervical subtotal corpectomy. MATERIALS AND METHODS: There were 12 adult Shannxi goats (2 y old) used in this study. The goats were divided into 2 groups based on postoperative survival periods of 3 (n=6) and 6 (n=6) months after surgery. Using an anterior surgical approach, a standard anterior C3 vertebra subtotal corpectomy and decompression of the spinal canal were performed, followed by implantation of the TCP device. Then all the goats were killed and underwent radiographic and histologic observations. RESULTS: The TCP implant procedures were successfully completed in all 12 goats without incidence of vascular or infectious complications. The range of motion of C2-C3 and C3-C4 segments were preserved in both of the groups. Three-dimensional images of specimens interface indicated confluent interdigitization of trabeculae at the prosthetic endplate-bone interface, without evidence of significant radiolucent lines or gaps. Histomorphometric analysis showed that there were a large number of fibrous tissue and a small amount of cartilage cells between the prostheses and bone in the 3 months' group. In the 6 months' group, part of fibrous tissue has changed into the cartilage tissue. CONCLUSIONS: Our data show that this prosthesis can maintain the stability of the cervical spine and retain the activity of the cervical spine in vivo. The findings in this study provide a foundation for ongoing clinical investigations using the TCP.

Clinical assessment of a CMC/PEO gel to inhibit postoperative epidural adhesion formation after lumbar discectomy: a randomized, control study.

PURPOSE: To evaluate effectiveness of carboxymethylcellulose/polyethylene oxide (CMC/PEO) gel in improving clinical outcomes after the first-time lumbar discectomy. METHOD: Ninety-three patients with herniated lumbar disc at L4-L5 or L5-S1 were enrolled and randomized into two groups: CMC/PEO gel treatment group and control group. All the patients underwent laminotomy and discectomy by posterior approach. The preoperative and postoperative Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores for lower-back pain and leg pain were analyzed and compared between two groups at 30- and 60-day time points. RESULTS: No patient presented with any clinically measurable adverse event during surgery. There were no significant differences between the treated group and the control group on the preoperative ODI and VAS scores. In general, the ODI and VAS scores decreased in both groups at all the time points. At the 30-day time point, the VAS scores for back pain and leg pain and the ODI scores in treatment group were lower by 9.9 % (P = 0.0302), 27.0 % (P = 0.0002) and 16.3 % (P = 0.0007) than those in control group. And at the 60-day time point, the ODI and VAS scores further decreased in both groups. The VAS scores for leg pain in treatment group were lower by 4.5 % than that in the control group (P = 0.0149). However, no significant difference was detected between two groups on the ODI and VAS scores for back pain. CONCLUSIONS: The results demonstrated that CMC/PEO gel is effective in reducing posterior dural adhesions in the spine with no apparent safety issues. It can improve patients' postoperative clinical outcome.

A comparative study on screw loosening in osteoporotic lumbar spine fusion between expandable and conventional pedicle screws.

INTRODUCTION: The aim of this study is to compare the rate of screw loosening and clinical outcomes of expandable pedicle screws (EPS) with those of conventional pedicle screws (CPS) in patients treated for spinal stenosis (SS) combined with osteoporosis. METHODS: One hundred and fifty-seven consecutive patients with SS received either EPS fixation (n = 80) or CPS fixation (n = 77) to obtain lumbosacral stabilization. Patients were observed for a minimum of 24 months. Outcome measures included screw loosening, fusion rate, Japanese Orthopaedic Association (JOA) scores and Oswestry disability index (ODI) scoring system, and complications. RESULTS: In the EPS group, 20 screws became loose (4.1%) in 6 patients (7.5%), and two screws (0.4%) had broken. In the CPS group, 48 screws became loose (12.9%) in 15 patients (19.5%), but no screws were broken. The fusion rate in the EPS group (92.5%) was significantly higher than that of the CPS group (80.5%). The rate of screw loosening in the EPS group (4.1%) was significantly lower than that of the CPS group (12.9%). Six EPS (1.8%) screws were removed. In the EPS group, two screws had broken but without neural complications. Twelve months after surgeries, JOA and ODI scores in the EPS group were significantly improved. There were four cases of dural tears, which healed after corresponding treatment. CONCLUSIONS: EPS can decrease the risk of screw loosening and achieve better fixation strength and clinical results in osteoporotic lumbar spine fusion.

Application of an expandable pedicle screw in the severe osteoporotic spine: a preliminary study.

PURPOSE: To investigate the clinical abstract and radiographic outcome of multi-axial expandable pedicle screws (MEPS) in patients with osteoporosis. METHODS: One hundred and twenty-five consecutive patients received MEPS from the UPASS spinal fixation system to obtain thoracolumbar or lumbosacral stabilization. All patients underwent bone mineral density (BMD) scans. The indications for use of the MEPS were spinal diseases with severe osteoporosis (degenerative diseases 46 cases, compression fractures 28 cases, lumbar tuberculosis 27 cases and revision spine surgery 24 cases). The pre-operative and three months post-operative functional evaluations were graded with JOA and VAS scoring system. One week, six months and 12 months after surgery, plain film and three-dimensional CT scans were obtained to evaluate the spinal fusion and fixation effectiveness of MEPS. RESULTS: The mean follow-up period was 18 months (ranged from 6 to 33 months). All patients suffered from severely osteoporosis with a decrease of 25.3% in BMD. The pre-operative JOA and VAS scores were 11.3±3.0 and 6.7±1.8 mm, respectively. Three months after operation, the JOA and VAS scores were 25.2±2.0 and 2.3±1.7 mm. The recovery rate was 78.1±11.5％ and the clinical results were satisfying. There were no instances of screw loosening or pullout of the MEPS and the screw-bone interface was excellent. The radiographic results showed that bone healing, both around the screws and inter-vertebral, was achieved. CONCLUSION: In osteoporosis spine surgery, excellent bone-screw interface and fixation strength can be achieved by using MEPS. MEPS are a novel approach to increase the pedicle screw fixation in osteoporotic and revision spine surgeries.

Functional outcomes and complications of reconstruction of the proximal humerus after intra-articular tumor resection.

OBJECTIVE: To evaluate functional outcomes and complications of reconstruction of the proximal humerus after intra-articular tumor resection. METHODS: Twenty-five patients who underwent Malawer I type resection and reconstruction of the proximal humerus for treatment of malignant or invasive benign tumors from August 1999 to August 2005 were evaluated. A variety of reconstructive procedures, including modular tumor prosthesis, osteoarticular allograft, and allograft-prosthetic composite (APC), were performed after resection of tumor. Oncological and radiographic parameters were evaluated. The modified Musculoskeletal Tumor Society (MSTS) evaluation system was used to assess limb functional outcome. RESULTS: The study group consisted of 10 male and 15 female patients, among which there were 20 malignant and 5 benign tumors. Restoration of shoulder function was achieved with a prosthesis in 6 patients, osteoarticular allograft in 12, and allograft-prosthesis composite in 7. At a mean of 48 months follow-up, 2 patients had died of disease. Two patients had local recurrence and 2 had metastatic disease. On the basis of the modified MSTS functional evaluation, the mean scores were 22.50 in the modular prosthesis group, 24.58 in the osteoarticular allograft group, and 27.00 in APC group, respectively. Joint instability and subluxation were serious complications affecting shoulder function in 10 patients. CONCLUSION: Reconstruction of the proximal humerus is an option that provides good relief of pain and preserves manual dexterity. Functional outcomes are better for APC and allograft than for modular prosthesis, due to retention of the rotation cuff. Complications in the APC group were less than in the allograft one.