Intra-operative Assessment of the Intellirod LOADPRO Spinal Rod Strain Sensor for Use During Kyphotic Corrective Surgery

Inclusion Criteria: * between 18 and 65 years of age * presenting with a confirmed diagnosis of kyphosis with deformity greater than 70 degrees requiring large segmental correction involving a minimum of six (6) levels * failure of conservative therapy requiring surgical correction of sagittal imbalance * sagittal imbalance due to loss of lumbar lordosis, and/or segmental kyphosis * participated in the informed consent process and has signed an Institutional Review Board approved informed consent Exclusion Criteria: * women who are pregnant * evidence of active (systemic or local) infection at time of surgery * prisoner or transient * history of known narcotic abuse * psychological disturbance past or present that could impair the consent process or ability to complete subject self-report questionnaires * ASA \> 3 * osteoporosis diagnosed on DEXA defined as a T-score ≥ -2.0 * Unable or unwilling to provide a full informed consent