Transpedicular decompression and pedicle subtraction osteotomy (eggshell procedure): a retrospective review of 59 patients.

Abstract

Outcomes of transpedicular decompression and/or osteotomy were analyzed retrospectively. To determine the effectiveness of decompression and correction, fusion stability, procedural safety, neurologic outcome, complication rates, and overall patient outcomes. The "eggshell" procedure is reserved for complex reconstructive problems in the treatment of acute trauma, deformity, tumor, or infection. The technique encompasses a range of procedures from simple transpedicular decompression and posterior fusion to more complex procedures, including transpedicular vertebrectomy and strut-grafting or pedicle subtraction (closing wedge) osteotomy with posterolateral fusion. These procedures are completed through a single posterior midline incision, with anterior spinal canal decompression a transpedicular approach, accompanied by a posterior or posterolateral fusion and internal fixation. From 1990 to 1998, 59 "eggshell" procedures were performed for 37 deformity cases and 22 tumor or infection cases. Forty-two patients had a minimum 2-year follow-up, averaging 4.5 +/- 2.5 years. Thirty-six patients were available for patient interview, physical examination, and radiographic analysis. Outcome data were collected using SF-36 and SRS instruments. No patients worsened neurologically, and all incomplete spinal cord injuries improved. All patients achieved solid fusion radiographically. Correction with osteotomy averaged 26 degrees. Systemic complication rates were low with a pulmonary complication rate of 5%. Blood loss averaged 2342 mL. Overall patient outcomes were below population norms, but patient satisfaction was very high. Overall, the results suggest that the "eggshell" procedure is a reliable and safe technique to achieve anterior decompression of the spinal canal and posterior stabilization through a single approach.