Low-intensity ultrasound (ExogenTM) for the treatment of fractures

Año de publicación: 2004

Low-intensity ultrasound (Exogen™) is a home-based treatment for certain fractures and frac-ture complications. The Société de l'assurance automobile du Québec (SAAQ) asked the Agence d'évaluation des technologies et des modes d'intervention en santé (AETMIS) to assess the efficacy and safety of this approach to fracture healing. This technology brief is an adaptation of an advice submitted to the SAAQ, which included information specific to this or-ganization's decision-making context. This re-port is intended for a wider audience that in-cludes, among others, professionals who treat patients with fracture complications. Fracture healing depends on a cascade of com-plex events. If the healing process is slower than expected, one speaks of delayed union , or, if the healing process stops, of nonunion. Se-vere fractures, especially of long bones, such as the tibia, are particularly susceptible to bone union problems. The definition of nonunion often specifies absence of healing 6 to 12 months after the fracture. The arrest of healing for more than three months, as documented by serial radiographs including multiple views, is also used to define nonunion. The treatment of fractures includes a growing number of various approaches and techniques, one of which is low -intensity ultrasound. This assessment comes at a time when the broaden-ing of the range of therapeutic options for dif-ferent fractures has not been accompanied by a comparative assessment of the different ap-proaches. The assessments are therefore insuffi-cient and often of relatively poor methodologi-cal quality. Also, for many fractures, the optimal treatment is the subject of clinical de-bate. Furthermore, despite the criteria often used to define nonunion, a fair proportion of these fractures will heal, even after a period of 12 months, if immobilization is maintained long enough. According to AETMIS’s assessment, the avail-able studies do not mention any adverse effects associated with this treatment modality. Given the efficacy and safety evidence, AETMIS con-siders that, with regard to the acceleration of healing and the prevention of nonunion, the level of evidence is insufficient to recommend the use of low-intensity ultrasound. However, in the case of nonunion of tibial fractures, the prognosis is so grim that it seems reasonable to consider the use of low-intensity ultrasound after failed surgical intervention and after the consolidation process, as measured by serial Presently, Exogen, a technology from the Smith and Nephew Corporation, seems to be the only technology marketed worldwide that uses low-intensity ultrasound to influence the fracture healing process. In Canada, as in the United States, this technology has been approved for the acceleration of the healing of certain fresh fractures with cast immobilization and for the treatment of nonunion. The prevention of non-union in certain higher-risk patient populations is also promoted as another indication. Upon an exhaustive analysis of the scientific literature, it was found that the quality of the evidence varies for the three indications men-tioned above: -There is no evidence that low-intensity ul-trasound can prevent nonunion in higher-risk patient populations; -According to a meta-analysis of three ran-domized trials with a small total number of patients, ultrasound may be effective in ac-celerating the healing of fractures treated without surgical intervention. Because of the exclusion from this meta-analysis, with no justification given, of one study in which the patients had undergone surgical stabili-zation and the small total number of patients in the meta-analysis, the efficacy evidence for the acceleration of healing should be considered weak; -The only studies that have examined the efficacy of Exogen in the treatment of non-union are retrospective case series with a self-paired study design. This type of analy-sis seems questionable in cases of nonunion because of the natural course of this healing problem.(AU)

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