CHRONIC AND INTERVENTIONAL PAIN

Spectral tissue sensing (STS) exploits the scattering and absorption of light by tissue. The main objective of the present study was to determine whether STS can discriminate between correct and incorrect placement of the needle tip during lumbar transforaminal epidural injection. This was a single-blind prospective observational study in 30 patientswith lumbar radicular pain scheduled for lumbar transforaminal epidural injection. Spectral tissue sensing data from the needle tip were acquired along the needle trajectory at 4 predefined measurement points and compared with ultrasound, fluoroscopy, and digital subtraction angiography images. Spectral tissue sensing data contained the full spectra. The lipid and hemoglobin content at the different measurement points was also calculated, and partial least-squares discriminant analysis was used to estimate the sensitivity and specificity of STS. Spectral tissue sensing identified correct needle placement with a sensitivity of 57% and a specificity of 82%, and intraforaminal versus extraforaminal locations were identified with a sensitivity of 80% and a specificity of 71%. (Reg Anesth Pain Med 2016;41: 520–526) Two factors are critical to the safety and technical success of lumbar transforaminal epidural injections (LTEIs): needle placement, which should be close to but not inside the nerve, and avoiding an intravascular needle-tip position. The needle can be placed close to a predetermined location using anatomical markers in combination with various imaging techniques such as fluoroscopy, ultrasound, and digital subtraction angiography (DSA). However, all of these techniques have limitations. Fluoroscopy combined with DSA is commonly used in LTEIs. Nevertheless, fluoroscopic needle guidance does not prevent nerve or vascular puncture or intraneural injection. The incidence of intravascular injection or simultaneous epidural and vascular injection during lumbar intraforaminal epidural injections is 6.1% to 11.3%. The sensitivity of real-time fluoroscopy in detecting intravascular needle placement is 71% compared with DSA. From the *Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center, Maastricht; †Philips Healthcare, Best; Departments of ‡Radiology and §Clinical Epidemiology & Medical Technology Assessment, Maastricht University Medical Center; and ‖Department of Anatomy and Embryology, Maastricht University, Maastricht; and ¶Department of Anesthesiology, VU University Medical Center Amsterdam, Amsterdam, the Netherlands. Accepted for publication March 2, 2016. Address correspondence to: Andrea J.R. Balthasar, MD, Department of Anesthesiology Pain Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, the Netherlands (e‐mail: a.balthasar@mumc.nl). Institutional funding for the study was received from Philips Electronics Nederland B.V. acting through Philips Research, Eindhoven, the Netherlands. The authors declare no conflict of interest. Trial registration: ClinicalTrials.gov Identifier: NCT01476709. Title: Photonic Needle and Intraforaminal Epidural Injection (Sleeve)—Observational Study in Humans Copyright © 2016 by American Society of Regional Anesthesia and Pain Medicine ISSN: 1098-7339 DOI: 10.1097/AAP.0000000000000419