engleski

Surgical obstacles of telescoping nails insertion in patients with osteogenesis imperfecta type III and IV, severe long bone deformity but without prior surgical intervention and with prolonged bisphosphonate therapy

Background The current surgical treatment of in children with severe types of osteogenesis imperfecta (OI) is correction and stabilisation with intramedullary (IM) telescoping nails. Major key factors to consider before surgery are frequency of fractures, age of the patient, degree of long bone deformity, pain caused by deformity and quality of bone which could be too weak due to disease itself, or too sclerotic due to prolonged bisphosphonate (BPS) therapy. Objectives The main purpose of this study is to present cohort OI patients with novel side- effect of prolonged BPs administration, but without surgical intervention. We are aiming to show morphological changes in IM anatomy of long bones with severe deformity. In addition, we identify surgical problems very close connected with changed bone anatomy and to suggest possible technical solutions. Design and methods The main inclusion criteria were patients with severe types of OI, severe deformation of long bone segment i.e. 60 or more degrees of deformity in one plane, prolonged treatment with BPs, patients without surgery prior measurement. Medical records of all patients were reviewed for information about total number of BPs infusions before the surgery. All preoperative radiographs with IM obliteration or sclerosis of the tibia or femur were retrospectively reviewed. To our best knowledge we are not aware of criteria or protocol for IM sclerosis measurement in patients with OI. We develop our own protocol and measured IM sclerosis on lateral radiographs only due to fact that segments were severe deformed and had a specific "rib shape". The start and the end points of sclerotic area were determined, and a whole surface of sclerotic area as well as percentage of sclerotic part was calculated. All radiographs were measured three times and final result was an arithmetic mean value. An angle of deformity i.e. varus and procurvatum was measured. Our control group were surgically treated OI patients without IM sclerosis but who matched our study cohort according to age and severity of disease. Results Thirteen children had surgery for OI in our hospital in the period of 30 months. The total number of operated segments was 33. In 28 segments Fassier-Duval (FD) telescoping nail was implanted. All children had type III and type IV and one child had type V of OI. In 11 patients 21 segments were identified without previous surgery. Out of those 21 segments there were 17 segments (14 femurs and 3 tibias) in 9 patients which had some amount of IM sclerosis, most often on the place of the apex of the deformity. All of included children were treated with intravenous infusions of pamidronate. Changes of the percentage of sclerotic part in measured area and the degree of deformity (procurvatum and varus) depending on total number of pamidronate cycles are presented in full text printed article. There were several obstacles in telescoping nails insertion in severe long bone deformity and significant IM sclerosis and/or IM obliteration: splitting of bone during drilling ; drill breakage ; “false route” ; malposition of implant ; prolonged surgical time and increased blood losses. On the basis of IM sclerosis measurement and results of this study there are suggestion on how to avoid surgical obstacles: precise preoperative planning ; careful surgical technique due to poor quality of bone ; gradual and slow IM reaming ; exchange of usage of surgical drill and manufacturer designed drill ; many orthogonal radiographic intra-operative controls ; excision of triangular sclerotic bone block (or trapezoidal when there is need for segment shortening). Conclusion To prevent long bone IM sclerosis one should decide when to perform surgical long bone deformity correction. According to presented results, the threshold for the operative treatment should be 15 cycles of BPs infusions. In addition, to other side effects of the prolonged BPs therapy there is a novel one – long bone IM sclerosis. Proposed technical tips and tricks to avoid surgical problems during IM telescoping nail insertion could help surgeons faced with similar situations when treating their OI patients.

severe osteogensis imperfecta ; surgery, telescoping nails, bisphosphonates

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