Neck reconstruction (AIIMS Box Technique) in the management of large femoral neck defects.

Large femoral neck defects are frequently associated with neglected femoral neck fractures, sequelae of infection, and failed fixation devices. The AIIMS box technique of neck reconstruction has the objectives of femoral head preservation and restoration of hip function in such cases. 32 patients (age range 20-56, average 38 years) with large femoral neck defects were treated from January 1990 to May 1997 and were followed up for a minimum of 10 years (range 10 to 17 years). The neck defect was converted into a box using osteal flaps (base from greater trochanter, anterior wall from head, quadratus femoris muscle pedicle graft posteriorly), which was filled with cancellous bone autograft, and stabilized with cancellous screws. Union occurred in all patients in a mean time of 16 weeks (range 12-20 weeks). One patient developed avascular necrosis (AVN) of femoral head. 8 out of 32 results were classified as excellent, 22 good and 2 fair. Good functional mobility was seen in all but two patients. Complications included coxa vara in two patients, and fixation problems in four patients. Large femoral neck defects can be managed successfully by this technique with preservation of the viability of the femoral head, and therefore the procedure should be considered in appropriate cases, particularly in young adults.

Outcome-based classification for assessment of thoracic pedicular screw placement.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: We propose a simple outcome-based classification for assessment of pedicle screw positions based on postoperative computed tomography scan. This bridges the gap between high rates of pedicle screw misplacement and minimal complications reported. SUMMARY OF BACKGROUND DATA: The main deterrent for the use of thoracic pedicular screws is the feared neurovascular complications due to screw "misplacements." The literature shows that only a small fraction of the misplaced screws actually causes any complication, and some misplacements can be acceptable both in terms of safety and their biomechanical strength. METHODS: Sixty patients with various spinal disorders were included in the study. The mean age was 29.6 years (range, 12-72 years). The patients were divided into 2 groups for assessment of pedicle screw placements using postoperative computed tomography scans: scoliosis group with 24 patients and the nonscoliosis group with 34 patients. Placements of screws were assessed using the outcome-based classification and the Rongming Xu criteria of screw placement. RESULTS: A total of 341 screws were assessed from 60 patients with various spinal disorders (scoliosis and nonscoliosis groups). Using the Rongming Xu criteria, the overall screw misplacement in scoliosis group was 50.72% (68 of 138) and that in nonscoliosis group was 45.45% (80 of 176 screws). Assessment of these screws using the outcome-based classification showed a high percentage of acceptable screw placements (type 1) - 89.85% (124 of 138 screws) in the scoliosis group and 86.93% (153 of 176 screws) in the nonscoliosis group. CONCLUSION: The literature shows consensus over high rates of pedicle screw misplacement, but low clinical complications, in the hands of the best of spine surgeons. The concept of acceptable screw placements and the outcome classification makes the pedicle screw assessment results correlate better with the clinical outcome.