PubMed · 9525163
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V I Sendax. 1996. Mini-implants as adjuncts for transitional prostheses.. https://pubmed.ncbi.nlm.nih.gov/9525163/
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The authors describe a simple and fast technique for removal of deeply situated broken pedicle screw fragments. The screw fragments are removed using a fine-serrated, conically cored bit with a light rough inner surface that is mounted on a common slow-speed drill capable of rotating clockwise and counterclockwise. The cored head of the bit is pressed and engaged on the cut surface of the broken screw, and the drill is made to turn in counterclockwise rotation; this, by means of friction, causes the two surfaces to interlock, and consequently the broken screw fragment backs out. This technique was used to retrieve both broken titanium and stainless steel screws, and satisfying results were obtained. There were no complications associated with the application of the technique, and the pedicle as well as the screw hole were always preserved, offering, in the event that the vertebral instability continued, the possibility of applying a new screw of slightly larger diameter at the same screw hole. This technical application offers the opportunity of removing deeply situated screw fragments by using a simple technique while maintaining the vertebral pedicle and screw-hole integrity.
STUDY DESIGN: This retrospective study was conducted to analyze the clinical results in 30 patients with cervical kyphosis that had been treated using cervical pedicle screw fixation systems. OBJECTIVES: To evaluate the effectiveness of a pedicle screw fixation procedure in correction of cervical kyphosis. SUMMARY OF BACKGROUND DATA: Correction of cervical kyphosis is a challenging problem in the field of spinal surgery. There have been several reports regarding surgical correction of cervical kyphosis; however, there have been no detailed reports on correction of cervical kyphosis using a pedicle screw fixation procedure. METHODS: Thirty patients with cervical kyphosis underwent correction and fusion using cervical pedicle screw fixation. Seventeen of 30 patients with flexible kyphosis (Group I) were managed by a posterior procedure alone. The remaining 13 patients with rigid or fixed kyphosis (Group II) had a combined anterior and posterior procedure. RESULTS: The average preoperative cervical kyphosis of 29.4 degrees improved to 2.3 degrees after surgery and was 2.8 degrees at the final follow-up. In Group I patients, preoperative kyphosis of 28.4 degrees improved to 5.1 degrees at the final follow-up. In contrast, preoperative kyphosis of 30.8 degrees in Group II patients improved to 0.5 degree at the final follow-up. Solid fusion was achieved in all patients. There were two patients with transient nerve root complications related to pedicle screw instrumentation. CONCLUSION: Cervical kyphosis in 30 patients was effectively corrected using a pedicle screw fixation procedure with no serious complications. Flexible kyphosis with segmental motion can be satisfactorily corrected by a single posterior procedure using pedicle screw fixation. However, circumferential osteotomies combined with a posterior shortening procedure involving a pedicle screw system are required to achieve the best correction of fixed kyphosis by bony union. Cervical pedicle screw fixation is the most advantageous instrumentation in the correction of cervical kyphosis.
STUDY DESIGN: This was a prospective study of 35 consecutive patients in whom pedicle screw position was assessed after surgery, using lateral radiographs and computed tomography. OBJECTIVE: To evaluate the accuracy of plain radiographs and computed tomography in assessment of pedicle screw position. SUMMARY OF BACKGROUND DATA: Imaging techniques, such as postoperative anteroposterior and lateral plain radiographs and computed tomography, are currently the primary means of assessing pedicle screw placement. METHODS: Postoperative radiographs and computed tomographic scans were used to evaluate the position of 220 pedicle screws inserted in the spines of 35 consecutive patients who underwent thoracic and lumbar spine fusion and instrumentation. No recognized neurologic complication resulted from pedicle screw placement. Screw position was graded as in, out, or questionable. All observations were performed independently by three observers. The authors also analyzed the position of the screws according to the underlying spinal disease. RESULTS: More misplaced screws were clearly seen on computed tomographic scans than on plain radiographs; however, this difference was not statistically significant. Interobserver differences were not statistically significant. Intraobserver differences approached statistical significance when the results of the two test were compared. CONCLUSIONS: Although the accuracy of computed tomographic imaging is better than that of plain radiographs, the difference does not reach statistical significance. Postoperative use of plain radiographs remains a reliable method for evaluation of pedicle screw insertion in the absence of neurologic deficit.