Radiographic evaluation of low back pain after lumbar fusion using Technetium-99 single-photon emission computed tomography: Impact on clinical decision-making and outcome

Abstract

Accurate identification of spinal pain generators is critical to selecting the optimal treatment strategy for patients with persistent low back pain following instrumented lumbar fusion. Conventional diagnostic imaging modalities such as CT and MRI often yield equivocal results in this patient population. The purpose of this study is to assess the utility of Tc-99 SPECT/CT as an adjunct to conventional imaging modalities in the identification of spinal pain generators in patients with persistent low back pain after a lumbar fusion. A retrospective cohort review of 18 patients with a history of at least 1-year of persistent low back pain following a lumbar fusion surgery was conducted. All patients had MRI and/or CT scans that did not definitively identify a spinal pain generator. Tc-99 SPECT/CT imaging was subsequently performed in this cohort and treatment was determined according to imaging results. For patients undergoing revision fusion, pre- and post-operative visual analogue scores (VAS) at last follow-up were analyzed. All pain sites not clearly visualized on CT or MRI were identified by increased uptake of Tc-99 on SPECT/CT. According to anatomic location of uptake, six patients in this cohort underwent revision lumbar fusion. For patients undergoing revision lumbar fusion, preoperative VAS score averaged 8.5 ± 0.29 and declined after surgery to 4.75 ± 0.95. Patients in our series who suffered from failed lumbar spinal surgery syndrome, and subsequently underwent SPECT/CT imaging leading to the identification of pain generators amenable to surgical treatment experienced significant reduction in VAS scores after revision surgery.

Keywords

• Low back pain
• Diagnostic imaging
• Pseudoarthrosis
• Revision spine surgery
• Technetium-99
• Single-photon Emission Computed Tomography/Computed Tomography (SPECT/CT)