MINIMALLY INVASIVE TECHNIQUES IN THE MANAGEMENT OF AMYELIC THORACOLUMBAR FRACTURES

A number of techniques have been described in the management of thoracolumbar spinal fractures, reporting a lack of consensus on their treatment. Internal fixation of unstable thoracolumbar spine fractures requires correction of the missing anterior column support. This usually entails insertion of a vertebral body replacement strut through an anterior approach, or a long posterior construct spanning at least two vertebrae. Above and two vertebrae below the fracture. Each approach requires extensive exposure of the spine, with prolonged operative times and profuse intraoperative blood loss. Part of the controversy is focused on the option of either surgery or conservative management for certain fracture types. For the past few years, minimally invasive techniques have been developed to limit surgery-related iatrogenic injury. The objective of this study was to report the results of percutaneous management of these lesions and the technical progress made based on our experience. We retrospectively reviewed the data of 21 patient with 31 thoracolumbar burst fractures without neurologic deficits admitted to our institution between 2010 and 2012. The surgical technique used systematically included balloon kyphoplasty and osteosynthesis via the posterior percutaneous approach. The two techniques have been used alone or in combination between them. The assembly was short, with screws in the vertebral pedicles above and below to the fracture and, when possible, even in the fractured vertebra. The primary outcome considered was the incidence of reoperation and loss of correction of kyphosis within the period of follow-up. We also evaluated the long-term functional status and pain. Isolated kyphoplasty for some stable fractures (like AO/Magerl A1.1, A1.2, A3.1), has the aim to obtain reduction of the fracture deformity by inflation of balloons in the vertebral body, followed by reinforcement with injection of cement into the cavity created, limiting at the same time the risk of intraoperative leakage. The possibility of using new materials, based on calcium phosphate, for the vertebral body augmentation extends its indication also to young patients. Kyphoplasty and percutaneous osteosynthesis systems may be used in combination for the treatment of unstable fractures (AO/Magerl: A3.1, A3.2, A3.3). The objective was to obtain maximal correction by ligamentotaxis and then to perform kyphoplasty secondarily to making raising of the vertebral plateau and to consolidate the vertebral body by reducing the pressure necessary in the balloons and thus reduce the risk of cement leakage. If direct support of the anterior column is not necessary (AO/Magerl: A2, A3, B), short-segment pedicle instrumentation is an attractive solution for fast stabilization of vertebral fractures, instrumenting only one vertebra above and one vertebra below the fracture and when possible, even the fractured vertebra. Percutaneous surgery by sparing the paravertebral muscles, should limit bleeding, reduce infection rates and postoperative pain, which would reduce the length of hospitalisation, make rehabilitation easier and faster and could limit the destabilisation of adjacent levels over the long term. The radiographical results at 1 year are equal to anterior stabilization and are better than other posterior-only techniques. Percutaneous augmented instrumentation is a non-fusion technique, therefore, after the fracture has healed, the instrumentation can be removed and motion restored to the instrumented levels. The results of this study support the growing interest in minimally invasive techniques in the management of spinal injuries with no neurological deficit. Rigorous patient selection is necessary and the learning curve must be taken into account. Prospective randomized studies with a larger number of patients and a longer follow-up will be essential in better defining the indications for these various techniques and to confirm the stability of the correction over time.