Minimally invasive sacroiliac fixation in oncologic patients with sacral insufficiency fractures using a fluoroscopy-based navigation system.

STUDY DESIGN: Surgical technique article with retrospective case series. SUMMARY OF BACKGROUND DATA: Sacral insufficiency fractures are commonly encountered in oncologic patients and constitute a cause for persistent lower back and pelvic pain. OBJECTIVE: The aim of this study is to describe the modified technique of navigated percutaneous sacroiliac (SI) fixation using multiple long screws per level that cross both SI joints and engage bilateral iliac bones; furthermore to evaluate its safety and efficacy in oncologic patients with sacral insufficiency fractures. METHODS: Six oncologic patients (3 male, 3 female, mean age: 58.8 y) with sacral insufficiency fractures who had undergone additional radiation therapy were operated with navigated percutaneous fixation. Two patients had failed preoperative sacroplasty and 1 had failed SI pinning. Eighteen SI screws were placed (15 at S1 level and 3 at S2). In the majority of cases the screws were long enough to engage bilateral ilium and sacrum. Additionally, 1 patient underwent percutaneous iliolumbar instrumentation and in 4 patients we performed concomitant sacroplasty or polymethylmethacrylate screw augmentation. The patients were followed for 18.8 months in average (range: 12-30 mo). Outcome was assessed using the Karnofsky Performance Status score (KPS), pain scale (0-10) and detailed neurologic examination. RESULTS: In 1 case, a revision of a screw was required due to radiculopathy. There was no perioperative morbidity or mortality. No hardware failure was encountered. There was significant improvement in KPS (P=0.04) and pain levels (P=0.02). CONCLUSIONS: These preliminary data suggest that navigated percutaneous SI screw fixation is a safe and effective intervention in terms of pain control and performance status improvement in oncologic patients with sacral insufficiency fractures. For optimal fixation, multiple long screws that engage both iliac bones may be inserted through the S1 level in a safe manner. The technique may be combined with sacroplasty or closed posterior instrumentation to augment the screw fixation. Further investigation is needed to compare this technique with other treatment modalities.

Role of motor-evoked potential monitoring in conjunction with temporary clipping of spinal nerve roots in posterior thoracic spine tumor surgery.

BACKGROUND CONTEXT: The vascular supply of the thoracic spinal cord depends on the thoracolumbar segmental arteries. Because of the small size and ventral course of these arteries in relation to the dorsal root ganglion and ventral root, they cannot be reliably identified during surgery by anatomic or morphologic criteria. Sacrificing them will most likely result in paraplegia. PURPOSE: The goal of this study was to evaluate a novel method of intraoperative testing of a nerve root's contribution to the blood supply of the thoracic spinal cord. STUDY DESIGN/SETTING: This is a clinical retrospective study of 49 patients diagnosed with thoracic spine tumors. Temporary nerve root clipping combined with motor-evoked potential (MEP) and somatosensory-evoked potential (SSEP) monitoring was performed; additionally, postoperative clinical evaluation was done and reported in all cases. METHODS: All cases were monitored by SSEP and MEPs. The nerve root to be sacrificed was temporarily clipped using standard aneurysm clips, and SSEP/MEP were assessed before and after clipping. Four nerve roots were sacrificed in four cases, three nerve roots in eight cases, and two nerve roots in 22 cases. Nerve roots were sacrificed bilaterally in 12 cases. RESULTS: Most patients (47/49) had no changes in MEP/SSEP and had no neurological deficit postoperatively. One case of a spinal sarcoma demonstrated changes in MEP after temporary clipping of the left T11 nerve root. The nerve was not sacrificed, and the patient was neurologically intact after surgery. In another case of a sarcoma, MEPs changed in the lower limbs after ligation of left T9 nerve root. It was felt that it was a global event because of anesthesia. Postoperatively, the patient had complete paraplegia but recovered almost completely after 6 months. CONCLUSIONS: Temporary nerve root clipping combined with MEP and SSEP monitoring may enhance the impact of neuromonitoring in the intraoperative management of patients with thoracic spine tumors and favorably influence neurological outcome.