A Comparison between Xenogenic Deproteinized Bone Substitute Pyrost® and Autologous Bone Graft in the Surgical Management of Simple Bone Cysts Clinical and Radiographic Results

Background:

The basic principle of surgical treatment of simple bone cysts has remained unchanged over the years, with curettage followed by packing of the defect with autogenic bone graft. With the introduction of ceramic biomaterials, an alternative packing material is available, avoiding the complications associated with cancellous bone harvesting or the use of a bioceramic implant. The aim of this study was to compare bony union and recurrence rate after packing of surgically treated simple bone cysts with either Pyrost^® or autogenic spongiosa.

Patients and Methods: 58 patients with simple bone cysts were treated by curettage followed by packing of the cavity with either high-porosity hydroxyapatite (Pyrost^®) inoculated with locally aspirated autogenic bone marrow (n = 26) or autogenic spongiosa (n = 32). Minimum X-ray follow-up was 36 months.

Results: No recurrence of the bone cyst was seen in 44 (75.9%) patients. According to Neer's criteria, complete obliteration was observed in 43.1% and residuals were found in 53.4%. The remaining 3.4% required subsequent operation due to recurrence. Entire packing of the cavity with xenogenic deproteinized bone substitution was radiologically confirmed in 80.8%. There were no significant differences (p = 0,76) between the use of autogenic spongiosa and the xenogenic deproteinized bone substitute concerning the rate of recurrency and radiographically verified complete bone consolidation.

Conclusions: Pyrost^® can be considered an alternative to conventional bone grafting in the treatment of simple bone cysts. The primary advantages of bone substitute materials ar their abundance and the avoidance of morbidity associated with bone harvesting. Questions concerning long-term biocompatibility and biomechanical aspects of the composite of unabsorbed bone substitute and bone warrant further investigation.