Purpose of the study

The aim of this work was to study the influence of the slice orientation of T2 axial images in numerical measurements of DSCA and study the effect that this change of slice angle would have on the morphological grading assessment.

Introduction: Several studies have looked at accuracy of thoracic pedicle screw placement, both in vivo and on cadavers, using fluoroscopy, image guidance, and anatomical landmarks. To our knowledge the upper thoracic spine (T1-T6) has not been specifically studied in the context of screw insertion and placement accuracy without the use of either image guidance or fluoroscopy. Our objective was to study the accuracy of placement of upper thoracic screws without the use of fluoroscopy, and report on implant related complications.

Methods: A single surgeon inserted a total of 60 screws in 13 consecutive non-scoliotic spine patients. These 60 screws were the first to be placed in the high thoracic spine in our institution. All previous surgeries used only a hook or wire technique for the upper thoracic spine. The most common diagnosis in our patient population was trauma. All screws were inserted using a modified Roy-Camille technique. Post operative axial computed tomography (CT) images were obtained for each patient and analyzed by an independent senior radiologist for placement accuracy. Furthermore we reviewed the operative records of each patient to record any implant related complications.

Results: No pedicle screw misplacements were found in 61.5% of the patients. Fifty three out of the 60 screws were placed correctly within all the pedicle margins. The overall pedicle screw placement accuracy was 88.3% using our modified Roy-Camille technique. Five medial and 2 lateral violations were noted in the 7 misplaced screws. One of the 7 misplaced screws was considered to be a marginal violation. No implant related complications were noted. Furthermore, no learning curve effect was noted as far as misplacement pattern was concerned.

Conclusion: We found that inserting pedicle screws in the upper thoracic spine based solely on anatomical landmarks was safe with an accuracy comparable to that of published studies on image guided surgery at the thoracic level.

Purpose: To determine if multidetector-row CT (MDCT) can replace conventional radiographs and be performed alone in severe trauma patients for the depiction of thoracolumbar spine fractures. Materials and Methods: One hundred consecutive severe trauma patients who underwent conventional radiographs of the thoracolumbar spine as well as thoraco-abdominal MDCT were prospectively identiþed. Conventional radiographs were reviewed independently by 3 radiologists and 2 orthopedic surgeons, and MDCT by 3 radiologists. Reviewers were blinded both to each other and to the results of the initial evaluation of these examinations. Presence, location and stability of fractures, as well as quality of reviewed imaging methods were assessed. Statistical analysis was performed to determine sensitivity and inter-observer agreement of each procedure, with clinical and radiological follow-up chosen as the reference standard. Time to perform each examination as well as involved radiation doses were also evaluated. Finally, a resource cost analysis was performed. Results: Sixty-seven fractured vertebrae in 26 of the patients were diagnosed. Twelve patients showed unstable spine fractures. Sensitivity and inter-observer agreement for unstable fractures amounted to 97.2% and 95.1% with MDCT, and 33.3% and 36.8% with conventional radiology. Average times in the performance of conventional radiographs and MDCT examinations amounted to 33 minutes and 40 minutes, respectively. Effective radiation doses involved in conventional radiographs of the spine and thoraco-abdominal MDCT amounted to 6.36 mSv and 19.42 mSv, respectively. MDCT afforded identiþcation of 145 associated traumatic lesions. Finally, costs of conventional radiographs and of MDCT amounted to 145 US$ and 880 US$ per patient, respectively. Conclusion: MDCT is a better test for depicting spine fractures than conventional radiographs. It can replace conventional radiographs and be performed alone in severe trauma patients.