Session IX - Pediatrics and Spine
Iliosacral Screw Stabilization Guided with Computed Tomography for Treatment of Posttraumatic Sacroiliac Disease: Preliminary Report
Bruce H. Ziran, MD1; Dan J. Heckman, MD1; Wade R. Smith, MD2;
Purpose: The sacroiliac joint is a common location of chronic lower back and pelvic pain with many known causes. When a painful sacroiliac joint is refractory to nonoperative therapy and causes severe functional inhibition, fusion of the sacroiliac joint may be considered. The traditional techniques for sacroiliac joint fusion involve an extensive surgical exposure with union rates of 60 to 85%, but the risks of bleeding, neurovascular injury, and infection are significant. A surgical protocol for sacroiliac joint stabilization without formal joint exposure and grafting, stemming from a technique described previously for fixation of posterior pelvic ring fractures, was evaluated. Our hypothesis was that, instead of achieving true arthrodesis, stabilization of the sacroiliac joint with the described technique would sufficiently stabilize it to provide ongoing relief. We report on the preliminary clinical outcomes and efficacy of this technique for treatment of sacroiliac joint disease.
Methods: Seventeen patients with chronic sacroiliac joint pain after some traumatic event, ranging from low-energy lifting and twisting, childbirth, to a nonoperatively treated posterior ring injury, were treated. Patients who had had prior posterior pelvic fixation were excluded. All patients underwent out-patient percutaneous CT-guided sacroiliac joint fusion with use of conscious sedation and local anesthesia. With use of the technique, at least one screw was placed into both S1 and S2, with an occasional third screw if sacral morphology permitted. Preoperatively, diagnostic CT-guided sacroiliac joint bupivacaine-steroid injections were used to confirm the sacroiliac joint as a source of pain and to quantify the response to intervention. Pain levels, evaluated by using a visual analog scale from 0 to 10, were assessed before injection (PRE-I), after injection (POST-I), and at the last follow up after fixation (FIX). Univariate analysis was used to compare interval scores, and Spearman correlations were performed to compare relations between pre- and post-injection and final scores. Only patients who experienced some pain relief after the diagnostic injection were offered the procedure. Perioperative and outcome data were recorded, including procedure time, amount of local anesthetic and intravenous sedation used, complications (infection, blood loss, nerve injury, or technical failure), accuracy of screw placement, pain relief, and cost. All procedures were performed on an outpatient basis, and patients were restricted to partial weight-bearing with an assistive device for 6 weeks. No other restrictions applied. At the first follow-up examination, patients were evaluated for their recall of the procedure.
Results: Forty-nine iliosacral screws were placed in 17 patients (10 women, 7 men) with a mean age of 35 years (range, 24 to 45) and a mean follow-up of 24 months (range,11 to 48). There were no complications, technical difficulties, or misplaced screws. The mean procedure time was 26 minutes per screw. The average amount of intravenous sedation was 142 mcg of fentanyl and 3 mg of versed, and the average amount of local anesthetic was 19 cc of lidocaine and 11 cc of bupivacaine. The mean pain levels were 8.3 (range, 3 to 10) PRE-I, 3.5 (range, 0 to 8) POST-I, and 3.3 (0 to 9) FIX. Overall, four patients (17.6%) had complete and 11 patients had significant pain relief at the final follow-up examination. Two patients (11.8%) experienced little to no pain relief; however, both suffered from multiple pain sources not of sacroiliac origin and had a limited response to the preoperative injection. None of the patients experienced increased pain after the procedure, and there were no infections or hardware or technical complications. Patients had little recall of the procedure. Univariate analysis found statistically significant differences between the patient's response to the diagnostic injection (PRE-I vs. POST-I, P <0.0001) and the patient's final condition compared with that before the procedure (PRE-I vs. FIX, P <0.0001) but not between the post-injection state and the final condition (POST-I vs. FIX, P = 0.8906). A statistically significant correlation (Spearman coefficient +0.57, P <0.02) was found between final pain score (FIX) and the magnitude of response to the diagnostic injection (difference of POST-I to PRE-I). Surgeon/implant/medication fees for the procedure averaged approximately $2600 per case as compared with the cost for standard sacroiliac screw placement in the operative suite ($12,500).
Conclusions: In the present study, we found that CT-guided stabilization of the sacroiliac joint for chronic dysfunction seems to provide satisfactory relief of sacroiliac joint pain. We found that patients with the greatest response to the diagnostic injection experienced a higher likelihood of pain relief. We surmise that by using two screws with some separation, the sacroiliac joint may be sufficiently stabilized that either a stable ankylosis or a spontaneous fusion occurs. Although we did not perform a CT evaluation of the sacroiliac joint looking for bony fusion, it is possible that, in the absence of such a phenomenon, there would be loosening over time and recurrence of symptoms. Thus far, this has not happened and the poor results appear related to selection criteria. Because the cause of vague and recalcitrant pelvic pain is complex, a diagnostic injection is not only important but also prognostic of response to treatment. The percutaneous approach under conscious sedation minimizes procedure time, recovery time, and complication rates relative to open fusion techniques. The results of this study are useful for traumatologists because we are often consulted regarding posttraumatic pelvic pain.