Utility of intraoperative real-time near-infrared fluorescence surgery for spinal schwannoma.

The authors report the first cases of fluorescence-guided spinal surgery of schwannomas using near-infrared fluorescence imaging with the delayed window indocyanine (ICG) green (DWIG) technique for accurate real-time intraoperative tumor visualization. Patients with intradural spinal schwannomas received 0.5 mg/kg ICG at the beginning of surgery. After 1 hour, using the DWIG technique, near-infrared spectroscopy (NIRS) detected the spinal schwannomas, showing the exact tumor location and boundaries. DWIG with NIRS microscopy confirmed the exact location of spinal schwannomas before and after opening of the dura mater, thereby facilitating successful tumor dissection from the surrounding tissues, tumor resection, and confirmation of tumor removal. The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21158.

Infected epidural hematoma of the lumbar spine associated with invasive pneumococcal disease.

Spinal epidural abscess (SEA) and spinal epidural hematoma (SEH) are neurologic emergencies with distinct etiologies and treatment. Despite similarities on magnetic resonance imaging (MRI), their differentiation is usually possible with meticulous history taking and neurologic examinations. We report an unusual case of SEA that developed from preceding SEH, posing a diagnostic challenge to physicians. A 65-year-old diabetic man suddenly experienced back pain and weakness of both legs when he lifted heavy luggage. He was afebrile, and his laboratory tests were mostly unremarkable. Spinal MRI consisting of T1-weighted, T2-weighted, and fat-suppressed T2-weighted images revealed an epidural mass over the L2-L4 spinous process. He was diagnosed with SEH based on his symptoms and MRI findings, and was treated conservatively using steroid pulse therapy. Despite initial improvement, he suddenly developed into septic shock and coma on the 10(th) hospital day, and died shortly thereafter. An autopsy revealed massive pus accumulation in the lumbar epidural space and brain, and a postmortem diagnosis of infected SEH associated with invasive pneumococcal disease was established. Serial MRI studies, including diffusion-weighted and/or gadolinium-enhanced T1-weighted images are warranted in patients with a presumed diagnosis of SEH receiving steroid therapy to detect such infectious transformation.

Changes in nerve root motion and intraradicular blood flow during an intraoperative straight-leg-raising test.

STUDY DESIGN: An intraoperative straight-leg-raising (SLR) test was conducted to investigate patients with lumbar disc herniation to observe the changes in intraradicular blood flow, which then were compared with the clinical features. OBJECTIVE: The legs of each patient were hung down from the operating table as a reverse SLR test during surgery, and intraradicular blood flow was measured. SUMMARY OF BACKGROUND DATA: It is not known whether intraradicular blood flow changes during the SLR test in patients with lumbar disc herniation. METHODS: The subjects were 12 patients with lumbar disc herniation who underwent microdiscectomy. The patients were asked to adopt the prone position immediately before surgery, so that their legs hung down from the operating table. A reverse SLR test was performed to confirm the angle at which sciatica developed. During the operation, the nerve roots affected by the hernia were observed under a microscope. Then the needle sensor of a laser Doppler flow meter was inserted into each nerve root immediately above the hernia. The patient's legs were allowed to hang down to the angle at which sciatica had occurred, and the change in intraradicular blood flow was measured. After removal of the hernia, a similar procedure was repeated, and intraradicular blood flow was measured again. RESULTS: Intraoperative microscopy showed that the hernia was adherent to the dura mater of the nerve roots in all patients. The intraoperative reverse SLR test showed that the hernia compressed the nerve roots, and that there was marked disturbance of gliding, which was reduced to only a few millimeters. During the test, intraradicular blood flow showed a sharp decrease at the angle that produced sciatica, which lasted for 1 minute. Intraradicular flow decreased by 40% to 98% (average, 70.6% +/- 20.5%) in the L5 nerve root, and by 41% to 96% (average, 72.0% +/- 22.9%) in the S1 nerve roots relative to the blood flow before the test. At 1 minute after completion of the test, intraradicular blood flow returned to the value obtained at baseline. After removal of the hernia, all thepatients showed smooth gliding of the nerve roots during the second intraoperative test, and there was no marked decrease in intraradicular blood flow. CONCLUSIONS: This study demonstrated that the blood flow in the nerve root is reduced when the nerve root is compressed in vivo.