[Cystic bone changes. Etiology, diagnosis, therapeutic principles and personal results of treatment].

Various bone disorders become manifest as cystic lesions. The differential diagnosis must include benign and malignant tumors and also non-tumorous lesions, such as osteomyelitis. The most important and most frequent types of genuine bone cyst are juvenile bone cyst and aneurysmal bone cyst. When juvenile bone cysts occur in adults they are called solitary bone cysts. Despite intensive research the pathogenesis of bone cysts is still unknown to this day, so that successful causal therapy is impossible. The main problem in the treatment of bone cysts is their high rate of recurrence, rates ranging between 20% and 50% having been cited in the international literature. A critical review of the literature reveals few publications with helpful follow-up results. Most of the publications are case reports, and they frequently merely describe various forms of treatment. More recent reports are mainly concerned with such methods as curettage, steroid injections, and continuous decompression with perforated screws. Until the early 1980s, segmental bone resection was the treatment of choice. Because of its high complication rate it has since been abandoned. In the last analysis, the only well-established method for which long-term results obtained in studies of any size have been published, is curettage of the cyst and grafting with cancellous bone from the iliac crest. In our series, 41 patients were treated with this method, and we recorded a recurrence rate of 17.1%. Complications were rare. The risk of recurrence depended on the age of the patient. A higher recurrence rate must be expected in children under the age of 10 years. For this reason, operative treatment should not be performed until after that age if possible. Newer methods, such as steorid injections and continuous decompression by means of perforated screws, had better results in some studies, but only according to a few authors. Further research is needed to show whether our method will yield good results in the long term when applied in larger patient collectives.