Cryo-Ablation in the Treatment of Aneurysmal Bone Cyst; Does it Improve Outcome?

Curettage with or without the use of adjuvants, such as cryo-ablation, is the standard treatment of Aneurysmal Bone Cyst (ABC). The purpose of this study is to compare the outcome of patients diagnosed with an ABC treated by curettage and high speed burr-drilling with and without additional cryo-ablation treated at our institution between the years 2008 and 2014.

All patients treated for an ABC, between January 2008 and December 2014 were included in this retrospective analysis. Patient characteristics (age, gender and tumor location, type of treatment, time of follow-up, recurrence rate and functional outcome) were noted and compared between the two main treatment options utilized, curettage and high-speed burr drilling versus curettage, high-speed burr drilling and adjuvant cryo-ablation.

50 patients were treated for an ABC during the study period. Five underwent resection/embolization only and were excluded. 18 patients underwent curettage and high-speed burr drilling (Group A), 27 patients had additional cryo-ablation with a closed Argon/Helium gas system (Group B) for a total cohort of 45 patients.

Average age of the patients was 17.2 years in group A versus 18.6 years in group B. No local recurrence was noted in group A and one only in group B, functional outcome as measured by MSTS93 with 24 months followup was available for 13 patients in Group A (28.1) and 20 in group B (28.3). Complications that necessitated additional surgery included one local recurrence, hardware removal in two and infection in another two patients respectively.

No statistically significant differences were found between both groups in respect to age, local recurrence, surgical complications and functional outcome. Time of follow-up was significantly longer in Group B as compared to Group A (41.7 months compared to 26.9 months, p=0.006).

In our opinion formal curettage with additional high-speed burr drilling achieves excellent tumor control rate with a low complication rate and good functional outcome, without the need for adjuvant treatment.