The PEEK cage is superior to the titanium cage in maintaining cervical interspace height and radiographic fusion after 1 and 2-levels anterior cervical decompression procedures.

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The findings suggest that preoperative diastolic blood pressure, intraoperative use of gelfoam for dura coverage and postoperative drain output are risk factors for symptomatic epidural hematoma after lumbar decompression surgery. Major blood loss and multilevel surgical procedure could result in poor recovery of muscle power. After spine decompression surgery, early detection and evacuation of hematoma are the key to avoid neurologic deterioration and have better clinical outcomes.

BackgroundPedicle screws with PMMA cement augmentation have been shown to significantly improve the fixation strength in a severely osteoporotic spine. However, the efficacy of screw fixation for different cement augmentation techniques, namely solid screws with retrograde cement pre-filling versus cannulated screws with cement injection through perforation, remains unknown. This study aimed to determine the difference in pullout strength between conical and cylindrical screws based on the aforementioned cement augmentation techniques. The potential loss of fixation upon partial screw removal after screw insertion was also examined.MethodThe Taguchi method with an L8 array was employed to determine the significance of design factors. Conical and cylindrical pedicle screws with solid or cannulated designs were installed using two different screw augmentation techniques: solid screws with retrograde cement pre-filling and cannulated screws with cement injection through perforation. Uniform synthetic bones (test block) simulating severe osteoporosis were used to provide a platform for each screw design and cement augmentation technique. Pedicle screws at full insertion and after a 360-degree back-out from full insertion were then tested for axial pullout failure using a mechanical testing machine.ResultsThe results revealed the following 1) Regardless of the screw outer geometry (conical or cylindrical), solid screws with retrograde cement pre-filling exhibited significantly higher pullout strength than did cannulated screws with cement injection through perforation (p = 0.0129 for conical screws; p = 0.005 for cylindrical screws). 2) For a given cement augmentation technique (screws without cement augmentation, cannulated screws with cement injection or solid screws with cement pre-filling), no significant difference in pullout strength was found between conical and cylindrical screws (p >0.05). 3) Cement infiltration into the open cell of the test block led to the formation of a cement/bone composite structure. Observations of the failed specimens indicated that failure occurred at the composite/bone interface, whereas the composite remained well bonded to the screws. This result implies that the screw/composite interfacial strength was much higher than the composite/bone interfacial strength. 4) The back-out of the screw by 360 degrees from full insertion did not decrease the pullout strength in any of the studied cases. 5) Generally, larger standard deviations were found for the screw back-out cases, implying that the results of full insertion cases are more repeatable than those of the back-out cases.ConclusionsSolid screws with retrograde cement pre-filling offer improved initial fixation strength when compared to that of cannulated screws with cement injection through perforation for both the conically and cylindrically shaped screw. Our results also suggest that the fixation screws can be backed out by 360 degrees for intra-operative adjustment without the loss of fixation strength.

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From July 2004 to June 2005, 19 patients with 25 discs underwent anterior cervical discectomy and interbody fusion (ACDF) in which polyetheretherketone (PEEK) cages were filled with freeze-dried cancellous allograft bone. This kind of bone graft was made from femoral condyle that was harvested during total knee arthroplasty. Patient age at surgery was 52.9 (28-68) years. All patients were followed up at least 1 year. We measured the height of the disc and segmental sagittal angulation by pre-operative and post-operative radiographs.

Identifying offending pathogens is crucial for appropriate antibiotic administration for infectious spondylitis. Although computed tomography (CT)-guided biopsy for bacteriologic diagnosis is a standard procedure, it has a variable success rate. Some reports claim percutaneous endoscopic discectomy and drainage offer a sufficient amount of tissue for microbiologic examination and easy application. We therefore compared the diagnostic value of CT guidance with that of endoscope guidance in 52 patients with suspected infectious spondylitis. Twenty patients underwent percutaneous endoscopic discectomy and drainage by an orthopaedic surgeon and the other 32 patients underwent CT-guided biopsies by a radiologist. Patients were followed a minimum of 12 months after treatment. Culture results of the biopsy specimens were recorded. Causative bacteria were identified more frequently with percutaneous endoscopy than in CT-guided biopsy (18 of 20 [90%] versus 15 of 32 [47%]). We observed no biopsy-related complications or side effects in either group. The data suggest percutaneous endoscopic discectomy and drainage yield higher bacterial recovery rates than CT-guided spinal biopsy. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Background: The association of lumbar spine instability between laminectomy and laminotomy has been clinically studied, but the corresponding in vitro biomechanical studies have not been reported. We investigated the hypothesis that the integrity of the posterior complex (spinous process-interspinous ligament-spinous process) plays an important role on the postoperative spinal stability in decompressive surgery.