Results of a minimally invasive technique for treatment of unicameral bone cysts

Abstract

Unicameral bone cysts are benign bone lesions commonly seen in pediatric patients. Several treatment methods have been described with variable results and high recurrence rates. We previously reported short-term success of a minimally invasive technique that includes combining percutaneous decompression and grafting with medical-grade calcium sulfate pellets. The purpose of this study was to review the additional long-term results with a minimum followup of 24 months (average, 37 months; range, 24-70 months). We identified 55 patients with an average age of 10.8 years (range, 1.3-18 years). Forty-one of 55 lesions occurred in the humerus and femur. Forty-four of 55 (80%) patients had a partial or complete response after initial surgery; of these, seven obtained a partial or complete response after a repeat surgery (cumulative healing rate, 94%). Two patients underwent a third surgery (cumulative healing rate, 98%). One underwent a third repeat surgery (cumulative healing rate, 100%). There were no major complications associated with the procedure. Two patients had a superficial infection that resolved with oral antibiotics. Although some patients required a repeat procedure, complete or partial response at a minimum 24 months' followup was achieved in all patients.

Level of evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Figures

Fig. 1A–G

A 13-year-old boy had a persistent UBC of the humerus after two steroid injections at an outside institution. (A) A preoperative anteroposterior radiograph shows the UBC. (B) A followup image taken 6 months after a first minimally invasive procedure shows the patient had an incomplete response, requiring a second surgery. (C) Intraoperative fluoroscopy shows the cystogram confirming the residual chamber; (D) a pituitary rounger was used to remove the cyst lining; the intramedullary decompression was performed using an angled curette (E) proximally (F) and distally. (G) The final result is seen after insertion of the MGCS pellet. The pellets extend beyond the cyst wall, confirming full decompression of the cavity.

Fig. 2A–C

A 12-year-old boy sustained a pathologic fracture through a UBC of the proximal humerus. (A) His initial radiograph shows a displaced fracture treated nonoperatively. (B) After fracture healing (6 weeks), the patient underwent a minimally invasive procedure. (C) Twelve weeks after surgery, the graft has been completely reabsorbed, there is a complete response to the surgery, and the humerus already is remodeling.