title: Effect of field size and length of plantar spur on treatment outcome in radiation therapy of plantar fasciitis: the bigger the better?
abstract: OBJECTIVE
  Radiation therapy is well established in the treatment of painful plantar fasciitis or heel spur. A retrospective analysis was conducted to investigate the effect of field definition on treatment outcome and to determine the impact of factors potentially involved.
  
  
  METHODS
  A review of treatment data of 250 patients (285 heels) with a mean follow-up time of 11 months showed that complete symptom remission occurred in 38%, partial remission in 32%, and no change in 19% (11% were lost to follow-up). Variables such as radiologic evidence of plantar spurs, their length, radiation dose, field size, age, sex, and onset of pain before administration of radiation therapy were investigated in univariate and multivariate regression analyses.
  
  
  RESULTS
  Treatment response depended upon age >53 years, length of heel spur ≤6.5 mm (or no radiologic evidence of a heel spur), and onset of pain <12 months before radiation therapy. Patients with these clinical prerequisites stood a 93% chance of clinical response. Without these prerequisites, only 49% showed any impact. No influence of field size on treatment outcome became evident.
  
  
  CONCLUSIONS
  Patients with short plantar heel spurs benefit from radiation therapy equally well as patients without any radiologic evidence. Moreover, smaller field sizes have the same positive effect as commonly used large field definitions covering the entire calcaneal bone. This leads to a recommendation of a considerable reduction of field size in future clinical practice.
authors.affiliation: Zentrum für Strahlentherapie und Radioonkologie, Bremen/Westerstede, Germany; Abteilung Strahlentherapie und Spezielle Onkologie, Medizinische Hochschule Hannover, Germany. Electronic address: hermann@strahlentherapie-westerstede.com.
authors.forename: Robert Michael
authors.initials: RM
authors.lastname: Hermann
authors.forename: Andreas
authors.initials: A
authors.lastname: Meyer
authors.forename: Alexandra
authors.initials: A
authors.lastname: Becker
authors.forename: Michael
authors.initials: M
authors.lastname: Schneider
authors.forename: Michael
authors.initials: M
authors.lastname: Reible
authors.forename: Ulrich Martin
authors.initials: UM
authors.lastname: Carl
authors.forename: Hans
authors.initials: H
authors.lastname: Christiansen
authors.forename: Mirko
authors.initials: M
authors.lastname: Nitsche
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D036981:Fasciitis, Plantar / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D005260:Female; D036982:Heel Spur / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000532:radiotherapy; D011859:Radiography; D011879:Radiotherapy Dosage; D012044:Regression Analysis; D012074:Remission Induction / Q000379:methods; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult