Bone Health Optimization in Adult Spinal Deformity Patients: A Narrative Review

Abstract

Osteoporosis and low bone mineral density (BMD) pose significant challenges in adult spinal deformity surgery, increasing the risks of complications such as vertebral compression fractures, hardware failure, proximal junctional kyphosis/failure, and pseudoarthrosis. This narrative review examines the current evidence on bone health optimization strategies for spinal deformity patients. Preoperative screening and medical optimization are crucial, with vitamin D supplementation showing particular benefit. Among the pharmacologic agents, bisphosphonates demonstrate efficacy in improving fusion rates and reducing hardware-related complications, though the effects may be delayed. Teriparatide, a parathyroid hormone analog, shows promise in accelerating fusion and enhancing pedicle screw fixation. Newer anabolic agents like abaloparatide and romosozumab require further study but show potential. Romosozumab, in particular, has demonstrated significant improvements in lumbar spine BMD over a shorter duration compared to other treatments. Surgical techniques like cement augmentation and the use of larger interbody cages can mitigate the risks in osteoporotic patients. Overall, a multifaceted approach incorporating medical optimization, appropriate pharmacologic treatment, and tailored surgical techniques is recommended to improve outcomes in adult spinal deformity patients with compromised bone quality. Future research should focus on optimizing the treatment protocols, assessing the long-term outcomes of newer agents in the spine surgery population, and developing cost-effective strategies to improve access to these promising therapies.

Keywords: compression fracture; denosumab; diphosphonates; kyphosis; osteoporosis; scoliosis; spinal fracture; teriparatide.

Figure 1

Spinal pathology due to osteoporosis. (A) Bone densitometry scan (DEXA) demonstrating a postmenopausal woman with osteoporosis of the lumbar spine, defined as a T-score (comparison with healthy adults) less −2.5 and a Z-score (comparison with similar peer group) less than −1.5, Green is normal bone density, yellow is low bone mass, and red is osteoporosis. (B) Acute vertebral compression fractures (yellow arrows). (C) Hardware failure with pedicle screw loosening, osteolysis, and migration. (D) Interbody cage subsidence, nonunion, and resultant spondylolisthesis.

Figure 2

Surgical treatment options for patients with osteoporosis. (A) Four-level kyphoplasty in an elderly woman with multiple thoracic vertebral compression fractures and thoracic hyperkyphosis. (B,C) AP and lateral X-rays from a hardware revision and fusion extension in a patient with osteoporosis and adjacent segment disease (ASD) at L2/3 following solid arthrodesis from previous L3–5 fusion. Note the new screws at L2 and L3 with cement augmentation through fenestrated screws. Larger interbody cages, such as those that can be inserted from an anterolateral approach, rest on the apophyseal ring of the vertebrae and thus provide stronger anterior column support and higher fusion rates. (D) Preoperative sagittal CT scan of a patient with advanced osteoporosis and a type II traumatic odontoid fracture. (E,F) Postoperative sagittal CT and lateral X-rays of the same patient 6 months following surgical stabilization and teriparatide treatment, demonstrating reduction and healing of the fracture.