Transpedicular decompression and pedicle subtraction osteotomy: review of 101 patients

Abstract

Daniel B. Murrey, MD, Charlotte, NC, USA; Samuel J. Chewning, MD, Statesville, NC, USA; Craig C. Brigham, MD, Frederick Finger, MD, Charlotte, NC, USA; Gary M. Kiebzak, MD, Houston, TX, USAThe “eggshell procedure” was originally described as a technique to allow anterior decompression and posterior fusion through a single transpedicular approach. The use of this technique has broadened to encompass a range of procedures from simple transpedicular decompression and posterior fusion to transpedicular vertebrectomy and strut grafting with posterolateral fusion or pedicle subtraction (closing wedge) osteotomy with posterolateral fusion. It is typically used for the treatment of acute trauma, deformity, tumor or infection. The common thread remains that all of these procedures are done through a single posterior midline incision, anterior spinal canal decompression is carried out through a transpedicular approach and it is accompanied by a posterior or posterolateral fusion. All or part of the anterior or posterior elements may be removed and strut grafting may or may not be necessary, depending on the goals of the particular case. The procedure is reserved for complex reconstructive problems and frequently is used as a salvage technique.In this study our objective was to determine the effectiveness or decompression and neurological outcome, the effectiveness of correction, the stability of fusion, the safety of the procedure and its complication rates and the overall patient outcomes. Independent chart review of 101 consecutive cases between 1990 and 1998 was carried out. Those available underwent patient interview, physical examination and radiographic analysis. Outcome data were collected using SF-36 and SRS outcome instruments.Of the 101 patients, 76 had 2-year or greater follow-up with an average of 6.0 ± 1.9 years. Fourteen patients died during the follow-up period, and 26 were lost to follow-up. The remaining 61 were interviewed, examined and radiographed. Chart review was performed on all 101 patients. Forty-two patients had the procedure for acute trauma, 37 for deformity and 22 for tumor or infection.Regarding fusion and correction of deformity, all patients achieved solid fusion radiographically and no loss of correction over time was identified. In patients with preoperative kyphosis, there was a tendency to undercorrect the sagittal alignment, with some patients retaining a slightly kyphotic posture. No overcorrection was identified. Hardware failure rate was less than 3%.Systemic complication rates were low, with a pulmonary complication rate of less than 4%. There were no perioperative deaths. Blood loss averaged 1,989 ± 1,899 cc, with higher losses seen in deformity cases and lower losses seen with acute trauma.Outcomes measured using the SF-36 and SRS questionnaires showed sex differences when correlating against length of follow-up. For women, self-image and general function scores decreased with increasing time from surgery. For men, function-related domains improved with increasing time from surgery. For both men and women, physical function, role physical, bodily pain and general health were significantly lower than normal subjects of the same age, even at longer-term follow-up. Results for social, emotional and mental health domains were not significantly different from normal.Outcomes measured in terms of pain control and narcotic use showed approximately two-thirds of patients using only NSAIDs or no pain medication. Less than 20% of patients used narcotics frequently. Patient satisfaction was high, with 92.9% of patients relatively or completely satisfied with their results, and 98% would recommend the procedure to another patient in similar circumstances.Overall, the results suggest that this procedure is a reliable and safe way to achieve anterior decompression of the spinal canal and posterior stabilization through a single approach.