There have been three major areas of clinical spinal deformity research that have led to global standardization over the past 20 years: adolescent idiopathic scoliosis (AIS) classification and treatment; the posterior-only approach to all spinal deformities; and posterior vertebral column resection (VCR) for the most severe spinal deformities. The Lenke et al system has been the worldwide standard of AIS classification with treatment recommendations. The system recommends which structural regions of the spine—proximal thoracic, main thoracic (MT), and thoracolumbar/lumbar (TL/L)—should be included in the fusion while avoiding fusion of the nonstructural regions.1 It also emphasizes selective fusion of MT (types 1C, 2C, 3C, and 4C) and TL/L (types 5C and 6C) curves when appropriate.2 Recently, use of the touched vertebra (TV) rule has been popularized for selecting the lowest instrumented vertebra (LIV). The TV is the lowest TL/L vertebra “touched” by the center sacral vertical line, and is often a safe LIV for most MT and double thoracic curves. For structural TL/L curves, the TV along with the lower-end vertebra of the TL/L curve are both analyzed to facilitate selection of the optimal LIV. In coming years, three-dimensional analysis and classification of AIS curves will become more common and ultimately replace the two-dimensional Lenke AIS classification system.
For many years, numerous adult spinal deformities were treated with a combined open anterior spinal fusion (ASF) and posterior spinal fusion. The open ASF was often performed through a thoracoabdominal approach when exposing the TL and lumbar spine, or a paramedian retroperitoneal approach to the lower lumbar segments. Both of these open extensile approaches, and especially the thoracoabdominal approach, were potentially morbid for the patient, both short- and long-term. Thus, by the turn of the century, several newer techniques had become available to spinal deformity surgeons that allowed them to avoid an ASF without sacrificing correction or fusion.3 These techniques included the use of pedicle screws throughout the entire thoracic, TL, and lumbar spine as a secure stabilization method.4,5 Spinal osteotomies provided the necessary posterior carpentry for realigning stiff adult spinal deformities.6 These included posterior column osteotomies releasing the posterior facets and ligaments, and three-column osteotomies that included pedicle subtraction osteotomies and VCRs depending on the overall stiffness, angulation, and realignment needed.7 Lastly, the use of transforaminal lumbar interbody fusion for lower lumbar circumferential fusion and various biologics has helped decrease pseudarthrosis often seen in adult long deformity fusions, while also avoiding the harvesting of iliac crest bone graft.
Since the late 1990s, the use of a posterior VCR for the most severe, stiff, and angulated spinal deformities has revolutionized the treatment of these challenging patients. The clinical and radiographic corrections are well accepted as optimal for these deformities, but widespread use has been tempered by high complication rates, including neurologic complications. The spinal disarticulation inherent to the VCR allows for tremendous correction, but working near an often stretched and attenuated spinal cord and the instability produced by the VCR renders the spinal cord susceptible to ischemic and mechanical compromise. However, the preoperative use of halo-gravity traction in appropriate patients, intraoperative neuromonitoring with appropriate responses as required, and technically proficient surgery has rendered the actual postoperative neurologic complication rate quite low among those experienced in this advanced surgery. This technique has become accepted worldwide—by surgeons and centers able to perform this complex surgery—as the standard of care for those patients with the most severe spinal deformities.8,9
1. Lenke LG, Betz RR, Harms J, et al. Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis. J Bone Joint Surg Am
2. Lenke LG, Betz RR, Clements D, et al. Curve prevalence of a new classification of operative adolescent idiopathic scoliosis: does classification correlate with treatment? Spine (Phila Pa 1976)
3. Kim YB, Lenke LG, Kim YJ, et al. The morbidity of an anterior thoracolumbar approach: adult spinal deformity patients with greater than five-year follow-up. Spine (Phila Pa 1976)
4. Kim YB, Lenke LG, Kim YJ, et al. Surgical treatment of adult scoliosis: is anterior apical release and fusion necessary for the lumbar curve? Spine (Phila Pa 1976)
5. Good CR, Lenke LG, Bridwell KH, et al. Can posterior-only surgery provide similar radiographic and clinical results as combined anterior (thoracotomy/thoracoabdominal)/posterior approaches for adult scoliosis? Spine (Phila Pa 1976)
6. Kim YJ, Lenke LG, Bridwell KH, et al. Free hand pedicle screw placement in the thoracic spine: is it safe? Spine (Phila Pa 1976)
7. Schwab F, Blondel B, Chay E, et al. The comprehensive anatomical spinal osteotomy classification. Neurosurgery
8. Gum JL, Lenke LG, Bumpass D, et al. Does planned staging for posterior-only vertebral column resections in spinal deformity surgery increase perioperative complications? Spine Deform
9. Cho SK, Lenke LG, Bolon SM, et al. Can intraoperative spinal cord monitoring reliably help prevent paraplegia during posterior vertebral column resection surgery? Spine Deform