title: CT-guided radiofrequency ablation of pediatric osteoid osteoma utilizing a water-cooled tip.
abstract: BACKGROUND
  Radiofrequency ablation (RFA) has a success rate of 70% to 90% in the treatment of osteoid osteoma (OO). Failures are due to malpositioning of probes or incomplete ablation, possibly related to conventional probes' small heating diameter (range, .5-.8 cm). Cooled-tip probes have a larger heating distance, ablating up to 3 cm, affecting a larger volume, and improving success rate in adults. Concerns regarding damage to surrounding structures and unknown effects on bony growth potential have delayed the widespread use of cooled tips in children. Our goal was to examine whether this technique, when added to conventional RFA, improves the clinical results and whether it carries any additional risks to children.
  
  
  METHODS
  A total of 22 patients with OO, 15 boys and 7 girls aged 3.5 to 18 years, were treated with the Cool-tip Tyco probe (Valleylab, Boulder, CO). Fifteen lesions were located in the femur, two in the tibia, and the remainder in the humerus, talus, calcaneus, second metatarsus, and sacrum. The OO was intra-articular in five patients: three in the femur, and one each in the calcaneus and talus. Average postoperative follow-up was 38.5 (range, 16-66) months.
  
  
  RESULTS
  The symptoms of all but one patient resolved immediately after a single RFA treatment. One patient experienced partial relief and underwent a second successful ablation. One patient experienced recurrence of disease after 18 months, and one superficial infection occurred. No fractures, neurovascular complications, or growth disturbances were found.
  
  
  CONCLUSIONS
  The cooled-tip probe is highly effective and safe for the treatment of pediatric osteoid osteoma, with no adverse events in this age group.
authors.affiliation: Department of Orthopedic Surgery, Hadassah-Hebrew University Medical Center, Jerusalem, Israel. peysera@hadassah.org.il
authors.forename: Amos
authors.initials: A
authors.lastname: Peyser
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Applbaum
authors.forename: Naum
authors.initials: N
authors.lastname: Simanovsky
authors.forename: Ori
authors.initials: O
authors.lastname: Safran
authors.forename: Ron
authors.initials: R
authors.lastname: Lamdan
mesh_terms: D000293:Adolescent; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D002648:Child; D002675:Child, Preschool; D003080:Cold Temperature; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D010017:Osteoma, Osteoid / Q000000981:diagnostic imaging / Q000601:surgery*; D011379:Prognosis; D011446:Prospective Studies; D015641:Radiography, Interventional; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome