title: Injectate volumes needed to reach specific landmarks in lumbar transforaminal epidural injections.
abstract: OBJECTIVE
  To identify the volumes of contrast material needed to reach specific landmarks during lumbar transforaminal epidural injections (L-TFEIs).
  
  
  METHODS
  Prospective, nonrandomized, observational human study.
  
  
  METHODS
  Academic/private pain management practice.
  
  
  METHODS
  Sixty-nine patients undergoing L-TFEIs were investigated. Sixty patients were included in this study.
  
  
  METHODS
  L-TFEIs were performed with the use of contrast-enhanced fluoroscopic visualization.
  
  
  METHODS
  After the appropriate spinal needle position was confirmed, up to 5.0 mL of nonionic contrast material was slowly injected. Under biplanar fluoroscopic guidance, contrast volumes were recorded as flow reached specific anatomic landmarks: ipsilateral neural foramen, ipsilateral disks superior and inferior to the injected level, and across the midline of the spinous process.
  
  
  RESULTS
  After 1.1 mL of contrast was injected, 100% of L-TFEIs spread to the medial aspect of the superior pedicle (PED) of the corresponding level of injection. After 2.8 mL of contrast was injected, 95% of L-TFEIs spread to the superior aspect of the superior intervertebral disk (IVD) of the corresponding level of injection. After 3.6 mL of contrast was injected, 95% of L-TFEIs spread to the inferior aspect of the inferior IVD of the corresponding level of injection. After 3 mL of contrast was injected, 88% of L-TFEIs spread to cover both the superior and inferior IVDs of the corresponding level of injection. After 4 mL of contrast was injected, 93% of L-TFEIs spread to cover both the superior and inferior IVDs of the corresponding injection. After 4 ml of contrast was injected, 55% of L-TFEIs spread beyond the midline of the spinous process, but barely.
  
  
  CONCLUSIONS
  This study demonstrates injectate volumes needed to reach specific anatomic landmarks in L-TFEIs. A volume of 4.0 mL of injectate reaches both the superior aspect of the superior IVD and the inferior aspect of the inferior IVD 93% of the time.
authors.affiliation: Orthopaedic and Spine Specialists, 1855 Powder Mill Road, York, PA 17403, USA. mbfurman@gmail.com
authors.forename: Michael B
authors.initials: MB
authors.lastname: Furman
authors.forename: Ariz R
authors.initials: AR
authors.lastname: Mehta
authors.forename: Ruby E
authors.initials: RE
authors.lastname: Kim
authors.forename: Jeremy I
authors.initials: JI
authors.lastname: Simon
authors.forename: Rikin
authors.initials: R
authors.lastname: Patel
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Lee
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Reeves
mesh_terms: D015360:Analgesia, Epidural / Q000379:methods*; D004824:Epidural Space / Q000187:drug effects; D005471:Fluoroscopy / Q000379:methods; D006801:Humans; D007089:Image Enhancement; D007268:Injections, Epidural / Q000379:methods*; D007405:Intervertebral Disc Displacement / Q000628:therapy; D017116:Low Back Pain / Q000534:rehabilitation*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D011446:Prospective Studies; D013130:Spinal Stenosis / Q000628:therapy; D013256:Steroids / Q000008:administration & dosage*
chemical_list: D013256:Steroids