Vertebral osteotomy

Abstract

The aim of deformity surgery is to realign the spine to (near) physiological curvatures. Selecting the extent of instrumentation is a balancing act: it should be as short as possible but as long as needed. To achieve optimal correction over the shortest possible section in a harmonious way, there must be similar elasticity throughout the area of the spine to be instrumented. The stiffer spinal segments require surgical intervention to achieve more mobility, and the necessary procedure is an osteotomy. The posterior approach for spinal osteotomy is recommended in young children. A posterior osteotomy of the same grade type (e.g. an Smith-Petersen[SP] osteotomy) is more effective in children than in adults due to the different vertebral dimensions and intervertebral disk height proportions; as such, an anterior approach in children is rarely necessary. Osteotomies and soft tissue releases fall on a continuum, ranging from the release of ligaments only, such as the cutting of the posterior or anterior longitudinal ligaments (PLL or ALL), all the way up to vertebral column resection (VCR). The osteotomy site should be determined based on the location of the pathology. Deformity is always associated with a relative shortening of the corresponding spinal segment: if the deformity occurs laterally, it leads to scoliosis; anteriorly, to kyphosis; and posteriorly, to lordosis. A combination of these is also possible. The deformity should be analyzed segmentally and the osteotomy planned for where there is a shortening; distraction, here, could be considered an option to normalize the length and form of the spine. Although experience in the treatment of adolescent/adult deformities is an advantage when treating early-onset spinal deformity, there are notable differences between the two. In the growing spine, the extent of the bony surface of the spine touched by the surgeon should be minimized in order to avoid the additional negative effect of disturbed growth due to altered periosteal function. Performing an osteotomy at a site is likely to promote fusion of the site. In general, fusion should be avoided in skeletally immature patients in whom growing rods are considered to be a viable option for the further guidance of spinal growth. Multimodal intraoperative neuromonitoring is mandatory since osteotomies are associated with high risk for neurologic injury.