Surgical correction of severe dystrophic neurofibromatosis scoliosis: an experience of 32 cases

Abstract

The surgical management of severe rigid dystrophic neurofibromatosis curves is a demanding procedure with uncertain results. Several difficulties are present in such patients including a poor bone stock, sharp angulation of these dystrophic curves and dural thinning or ectasia. The aim of this work was to review the clinical and radiographic outcomes of three-dimensional correction of severe rigid neurofibromatosis curves analyzing its efficacy, safety and possible complications. Thirty-two patients were followed up for an average of 6.5 years (range 3-9 years). The average age at surgery was 14 years (range 11-19 years). All patients had typical dystrophic curves, and the apex of the deformity was thoracic (n = 13), thoracolumbar (n = 14) and lumbar (n = 5). All patients had a two-staged procedure; an anterior release followed latter by posterior hybrid instrumentation augmented by sublaminar wires. Two wires were usually placed immediately below the proximal anchor, and several sublaminar wires were always passed at the apex of the deformity. There were a total of 142 wires with an average of 6.5 wires/patient (range 5-8 wires). The mean preoperative Cobb angle of the scoliotic curve was 102.2 degrees (range 71 degrees-114 degrees) corrected to an average of 39 degrees (range 16 degrees-49 degrees), and the loss of correction had an average of 4 degrees. The mean preoperative sagittal plane deformity was 49 degrees corrected by an average of 61%, and rotation was corrected by an average of 34%. There were no dural tears during passage of the sublaminar wires, no implant-related complications and no permanent neurologic deficits. The use of extensive and vigorous anterior release with posterior hybrid instrumentation has proved useful and effective in the treatment of these severe deformities; sublaminar wires allow safe gradual correction and even distribution of forces over multiple anchor points improving the correction achieved and decreasing implant-related complications.

Evaluation of Efficacy and Safety of All Pedicle Screw Posterior-Only Surgery in Patients with Dystrophic Neurofibromatosis Scoliosis

“…20 However, with the use of the thirdgeneration all pedicle screws instrumentation and using posterior release/osteotomies, safe and good correction of the deformity can be achieved. 18,20 In this study, scoliotic curves up to 90 • with flexibility index up to 25% and kyphosis up to 90 • were corrected posteriorly only. Li et al 20 and Deng et al 8 reported similar good results using posterioronly surgery.…”

“…8 Anterior-posterior surgery was the traditional treatment of dystrophic NF-1 scoliosis because posterior fixation alone has been associated with increased incidence of failure and loss of correction by many studies. 15,18,19,23,24 But these studies were using either the Harrington distraction rod, hooks system, or hybrid instrumentation. These instrumentation systems rely on fixing only the posterior column and cannot withstand the applied stresses during correction of deformity and during the follow-up period.…”

“…Anterior surgery was recommended in severe rigid and kyphoscoliotic deformity because of the weak osteoporotic bone and spinal instability leading to high stresses on the hooks during and after correction 18 and also because the posterior surgery combines compression and the anterior surgery combines distraction of the vertebrae making the correction of deformity more complete. 20 However, with the use of the thirdgeneration all pedicle screws instrumentation and using posterior release/osteotomies, safe and good correction of the deformity can be achieved.…”

Posterior-only surgical correction of dystrophic scoliosis in 31 patients with neurofibromatosis Type 1 using the multiple anchor point method

“…Treatment strategies remain controversial due to dystrophic vertebral deformity, very thin pedicles, osteoporosis, and rapid progression. 7 Kim et al 6 believed that patients with a dystrophic scoliotic deformity of 20°-40° and kyphotic angle < 50° were simply managed with posterior spinal instrumentation and fusion; to obtain better efficacy of correction and reduce the risk of pseudarthrosis, anteroposterior instrumented fusion was recommended as the most reliable surgical option in the presence of a dystrophic scoliotic deformity greater than 40° or kyphotic angle greater than 50°. 11 However, other authors 1,2 reported that the clinical efficacy of anteroposterior instrumented fusion was still not satisfactory due to severe hyperkyphosis and vertebral rotation in young patients.…”

Escoliose Distrófica na Neurofibromatose Tipo I

“…2 Na neurofibromatose tipo 1 as manifestações ortopédicas são frequentes, sendo a escoliose evidente em até cerca de 60% dos doentes afetados. 3 Esta pode manifestar-se de duas formas: deformidades distróficas e deformidades não distróficas.…”