title: Contrast-enhanced MR imaging performed after successful lumbar disk surgery: prospective study.
abstract: A prospective study was undertaken to establish the normal spectrum and timing of gadolinium-enhanced magnetic resonance (MR) imaging findings in 15 patients who had resolution of symptoms after successful lumbar disk surgery. Enhancement of the facet joints (in 88% of disk levels) and paraspinal muscles (100%) decreased gradually after surgery. Enhancement of the decompressed nerve root tracked proximally toward the conus medullaris in 62% at 3 weeks and was absent in all by 6 months postoperatively. Areas of intermediate signal intensity with peripheral enhancement and mass effect were seen on T1-weighted images at the site of the original disk herniation in 38% at 3 weeks and 12% at 3 months, despite complete relief of leg pain. These results reveal that even in successfully treated (asymptomatic) patients, residual mass effect on the neural elements may frequently simulate a recurrent or residual disk fragment. There is an orderly progression of imaging changes during the first 6 months after lumbar surgery that limits the interpretation of MR examinations during that period.
authors.affiliation: Department of Orthopaedic Surgery, George Washington University Medical Center, Washington, DC 20037.
authors.forename: S D
authors.initials: SD
authors.lastname: Boden
authors.forename: D O
authors.initials: DO
authors.lastname: Davis
authors.forename: T S
authors.initials: TS
authors.lastname: Dina
authors.forename: C P
authors.initials: CP
authors.lastname: Parker
authors.forename: S
authors.initials: S
authors.lastname: O'Malley
authors.forename: J L
authors.initials: JL
authors.lastname: Sunner
authors.forename: S W
authors.initials: SW
authors.lastname: Wiesel
mesh_terms: D000328:Adult; D003287:Contrast Media; D004338:Drug Combinations; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000175:diagnosis / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine; D009942:Organometallic Compounds; D004369:Pentetic Acid; D011183:Postoperative Complications / Q000175:diagnosis; D011184:Postoperative Period; D011446:Prospective Studies; D012016:Reference Values; D013126:Spinal Nerve Roots / Q000473:pathology
chemical_list: D003287:Contrast Media; D004338:Drug Combinations; D009942:Organometallic Compounds; D008536:Meglumine; D004369:Pentetic Acid; D019786:Gadolinium DTPA