Clinical evaluation of a bone cement-injectable cannulated pedicle screw augmented with polymethylmethacrylate: 128 osteoporotic patients with 42 months of follow-up.

OBJECTIVES: To evaluate the safety and efficacy of a novel bone cement-injectable cannulated pedicle screw augmented with polymethylmethacrylate in osteoporotic spinal surgery. METHODS: This study included 128 patients with osteoporosis (BMD T-score -3.2±1.9; range, -5.4 to -2.5) who underwent spinal decompression and instrumentation with a polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screw. Postoperative Visual Analogue Scale scores and the Oswestry Disability Index were compared with preoperative values. Postoperative plain radiographs and computed tomography (CT) scans were performed immediately after surgery; at 1, 3, 6, and 12 months; and annually thereafter. RESULTS: The mean follow-up time was 42.4±13.4 months (range, 23 to 71 months). A total of 418 polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screws were used. Cement extravasations were detected in 27 bone cement-injectable cannulated pedicle screws (6.46%), mainly in cases of vertebral fracture, without any clinical sequela. The postoperative low back and lower limb Visual Analogue Scale scores were significantly reduced compared with the preoperative scores (<0.01), and similar results were noted for the Oswestry Disability Index score (p<0.01). No significant screw migration was noted at the final follow-up relative to immediately after surgery (p<0.01). All cases achieved successful bone fusion, and no case required revision. No infection or blood clots occurred after surgery. CONCLUSIONS: The polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screw is safe and effective for use in osteoporotic patients who require spinal instrumentation.

Application of Cement-Injectable Cannulated Pedicle Screw in Treatment of Osteoporotic Thoracolumbar Vertebral Compression Fracture (AO Type A): A Retrospective Study of 28 Cases.

OBJECTIVE: To evaluate safety and effectiveness of the novel polymethyl methacrylate-augmented bone cement-injectable cannulated pedicle screw (CICPS) in patients with thoracolumbar vertebral compression fractures (AO type A) associated with osteoporosis. METHODS: We conducted a retrospective cohort study of 28 patients treated for osteoporosis-related thoracolumbar vertebral body compression fracture at our facility between 2011 and 2015. Treatment involved posterior thoracolumbar fusion or lumbar fusion using CICPS. Treatment effectiveness was evaluated using visual analog scale and Oswestry Disability Index scores, degree of fracture reduction, and correction of kyphosis. The safety of CICPS was mainly assessed in terms of intraoperative and postoperative complications. Radiography, computed tomography, and magnetic resonance imaging outcomes were also assessed. RESULTS: All 28 patients had severe osteoporosis. The visual analog scale score at final follow-up (0.50 ± 0.69) was significantly (P < 0.001) lower compared with before surgery (4.93 ± 1.30). The Oswestry Disability Index score had also decreased from 57.39% ± 14.46% to 6.83% ± 15.38% at final follow-up (P < 0.001). Radiologic evaluation of vertebral height and Cobb angle showed good fracture reduction and satisfactory correction of kyphosis (preoperative vs. final follow-up, P < 0.001). There were no instances of screw loosening or symptomatic complications except for a few cases of cement leakage from CICPS (10.3%; cement leakage most common in AO type A3.3). CONCLUSIONS: The use of CICPS and polymethyl methacrylate is an effective and safe surgical technique for management of osteoporosis-related vertebral fractures (AO type A), with good clinical outcomes and low complications rates.

Effects of site-specific polyethylene glycol modification of recombinant human granulocyte colony-stimulating factor on its biologic activities.

BACKGROUND: Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is a long-chain cytokine that is administered to stimulate the production of white blood cells (WBCs) to reduce the risk of serious infection in immunocompromized patients. However, to achieve sustained stimulation of WBC production, rhG-CSF must be administered frequently, thus limiting its clinical use. METHODS: We conjugated rhG-CSF with linear monomethoxy-polyethylene glycol (PEG) maleimide at amino acid residue Cys(17) to test our hypothesis that this could extend the in vivo half-life of rhG-CSF in blood. RESULTS: The mono-PEG rhG-CSF became more stable to pH, temperature, and enzyme degradation in vitro, and had granulopoietic activity that was superior to the unmodified form in vivo. The granulopoietic activity of PEG-G-CSF was 2.82-fold greater than that of unmodified G-CSF. CONCLUSIONS: These results indicate that the thiol-specific PEGylation remarkably prolonged the half-life of rhG-CSF and represents a novel strategy to address the more clinically acceptable therapeutic application of hemopoietic growth factor.

Clinical evaluation of a bone cement-injectable cannulated pedicle screw augmented with polymethylmethacrylate: 128 osteoporotic patients with 42 months of follow-up

OBJECTIVES: To evaluate the safety and efficacy of a novel bone cement-injectable cannulated pedicle screw augmented with polymethylmethacrylate in osteoporotic spinal surgery. METHODS: This study included 128 patients with osteoporosis (BMD T-score −3.2±1.9; range, −5.4 to -2.5) who underwent spinal decompression and instrumentation with a polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screw. Postoperative Visual Analogue Scale scores and the Oswestry Disability Index were compared with preoperative values. Postoperative plain radiographs and computed tomography (CT) scans were performed immediately after surgery; at 1, 3, 6, and 12 months; and annually thereafter. RESULTS: The mean follow-up time was 42.4±13.4 months (range, 23 to 71 months). A total of 418 polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screws were used. Cement extravasations were detected in 27 bone cement-injectable cannulated pedicle screws (6.46%), mainly in cases of vertebral fracture, without any clinical sequela. The postoperative low back and lower limb Visual Analogue Scale scores were significantly reduced compared with the preoperative scores (<0.01), and similar results were noted for the Oswestry Disability Index score (p<0.01). No significant screw migration was noted at the final follow-up relative to immediately after surgery (p<0.01). All cases achieved successful bone fusion, and no case required revision. No infection or blood clots occurred after surgery. CONCLUSIONS: The polymethylmethacrylate-augmented bone cement-injectable cannulated pedicle screw is safe and effective for use in osteoporotic patients who require spinal instrumentation.