RECONSTRUCTION OF FAILED LUMBAR SURGERY WITH NARROW AO-DCP PLATES FOR SPINAL ARTHRODESIS

Forty-five patients underwent surgical reconstruction with transpedicular fixation of the lumbar spine with narrow AO DCP plates. Preoperatively, all patients underwent spinal imaging with either magnetic resonance imaging, computed tomography, or myelogram as well as provocative discography to determine the location and the number of symptomatic segments. The minimum follow-up in this series was 2 years. The determination of solid posterior fusion in the presence of plate instrumentation was difficult. The patients in the series were classified as having 1) solid fusion; 2) radiographic flaws within the posterolateral fusion without implant failure; or 3) frank pseudarthrosis with implant failure. Thirty-six (80%) of the patients had a solid fusion, 9 of whom required an additional anterior interbody fusion to obtain symptom control. Twenty percent of the patients in the series had radiographic evidence of reabsorption without implant failure. Four patients in the series (8.8%) had screw breakage, three of which required anterior interbody fusions. The highest rate of reabsorption and pseudarthrosis implant failure was in the 12 patients who had three-level instrumentation; 33% of these patients required anterior interbody fusion to obtain a solid arthrodesis. The average preoperative pain scale was 8.9, and the average postoperative pain scale was a 3.3. Twenty-two patients in the series were cigarette smokers and had a slightly lower fusion rate than non-smokers. They did, however, have a higher use of narcotics after surgery. Fourty percent of the patients in this series continued to have radiculopathy after their reconstruction. This study demonstrates the utility of transpedicular fixation in salvage lumbar surgery in obtaining a solid arthrodesis with a beneficial clinical result. Anterior interbody fusions are highly successful in the management of pseudarthrosis and implant failure after transpedicular instrumentation.