Research

Introduction: The revision of symptomatic cage pseudoarthrosis can be performed by either posterior stabilization alone or circumferential revision including anterior cage removal and posterior stabilization (AP). The purpose of this study is to identify and describe the perioperative complications of each treatment.
Results: 29 consecutive patients who underwent revision surgery for lumbar interbody cage pseudoarthrosis were reviewed. Time interval between the index surgery and the revision ranged from 6 to 81 months (Median = 20 months). AP revision was performed in 17 patients (59%), 11 patients (38%) underwent posterior stabilization alone and one patient underwent an anterior alone approach. Twenty-nine cages were removed in 17 patients (20 from L5-S1; 4 from L4-L5; one each from L1-2, L2-3, L3-4). Two-thirds (8 out of 12) of the cages encountered at L4-L5 were deemed impossible to remove due to the risk of vascular injury, while only 20% (5 out of 25) at L5-S1 were not removed.
Typically, it was found to be more difficult to remove the right-sided cage at L4-L5, where as at L5-S1 the left side was found to be more difficult. Three of the AP patients (18%) had iliac vein lacerations requiring repair; all three remained hemodynamically stable and surgery was completed. A fourth patient had a ureter injury requiring subsequent nephrectomy. No neurologic sequelae were encountered with anterior cage removal in those cases where cage placement was originally from the posterior approach. No other intraoperative complications were identified in the AP group and no intraoperative complications were identified in the posterior only group. Three AP patients (18%) and two posterior alone patients (17%) had complications, including two infections (one AP, one posterior alone), one radiculopathy (posterior alone), and two prolonged ilius (both AP). As expected, AP revision as compared to the one-sided revisions resulted in increased operative time (477 minutes and 222 minutes, respectively), blood loss (1070 cc and 477 cc, respectively) and days of hospitalization (6 and 4, respectively).
Conclusions: Circumferential revision including cage removal and posterior stabilization is associated with increased perioperative complications, as well as longer operative time, hospitalization and blood loss. It remains to be answered by this ongoing study if outcomes differ to justify the increased morbidity.