title: Correlation of preoperative MRI with the long-term outcomes of dorsal root entry zone lesioning for brachial plexus avulsion pain.
abstract: OBJECT Lesioning of the dorsal root entry zone (DREZotomy) is an effective treatment for brachial plexus avulsion (BPA) pain. The role of preoperative assessment with MRI has been shown to be unreliable for determining affected levels; however, it may have a role in predicting pain outcomes. Here, DREZotomy outcomes are reviewed and preoperative MRI is examined as a possible prognostic factor. METHODS A retrospective review was performed of an institutional database of patients who had undergone brachial plexus DREZ procedures since 1995. Preoperative MRI was examined to assess damage to the DREZ or dorsal horn, as evidenced by avulsion of the DREZ or T2 hyperintensity within the spinal cord. Phone interviews were conducted to assess the long-term pain outcomes. RESULTS Between 1995 and 2012, 27 patients were found to have undergone cervical DREZ procedures for BPA. Of these, 15 had preoperative MR images of the cervical spine available for review. The outcomes were graded from 1 to 4 as poor (no significant relief), good (more than 50% pain relief), excellent (more than 75% pain relief), or pain free, respectively. Overall, DREZotomy was found to be a safe, efficacious, and durable procedure for relief of pain due to BPA. The initial success rate was 73%, which declined to 66% at a median follow-up time of 62.5 months. Damage to the DREZ or dorsal horn was significantly correlated with poorer outcomes (p = 0.02). The average outcomes in patients without MRI evidence of DREZ or dorsal horn damage was significantly higher than in patients with such damage (3.67 vs 1.75, t-test; p = 0.001). A longer duration of pain prior to operation was also a significant predictor of treatment success (p = 0.004). CONCLUSIONS Overall, the DREZotomy procedure has a 66% chance of achieving meaningful pain relief on long-term follow-up. Successful pain relief is associated with the lack of damage to the DREZ and dorsal horn on preoperative MRI.
authors.affiliation: Department of Neurological Surgery, University of Washington, Seattle, Washington;
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Ko
authors.affiliation: Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon; and.
authors.forename: Alp
authors.initials: A
authors.lastname: Ozpinar
authors.affiliation: Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon; and.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Raskin
authors.affiliation: Department of Neurological Surgery, University of California, San Francisco, California.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Magill
authors.affiliation: Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon; and.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Raslan
authors.affiliation: Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon; and.
authors.forename: Kim J
authors.initials: KJ
authors.lastname: Burchiel
mesh_terms: D000328:Adult; D001917:Brachial Plexus / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000000981:diagnostic imaging / Q000601:surgery*; D010147:Pain Measurement; D012189:Retrospective Studies; D019051:Rhizotomy; D013126:Spinal Nerve Roots / Q000000981:diagnostic imaging / Q000601:surgery*; D013223:Statistics as Topic
keywords: BPA = brachial plexus avulsion; DREZ = dorsal root entry zone; DREZotomy; DZEZotomy = dorsal root entry zone lesioning; VAS = visual analog scale; brachial plexus avulsion; dorsal root entry zone; neuropathic pain