Reduced Preoperative Cervical Spine Flexion-Extension Range of Motion Is Associated With the Development of Upper Thoracic Proximal Junction Kyphosis in Adult Spinal Deformity Patients

= 0.0085). On multivariable models for the development of S-PJK/PJF, reduced baseline cervical flexion and ROM were independent risk factors yielding threshold values of 22.8° and 48.2°, respectively.ConclusionMultivariable models for the development of S-PJK/PJF demonstrated that reduced baseline cervical ROM and flexion were independent risk factors yielding threshold values of 48.2° and 22.8°, respectively. All of S-PJK/PJF patients had preop flexion <22.8°. Flexion-extension radiographs provide a quick and easy option at a relatively low cost to offer additional information that may aid in surgical planning and shared decision making with the patient regarding potential outcomes.