SYMPHONY™ OCT System for Instabilities of the Upper Thoracic and Cervical Spine

This will be a prospective, multi-centre study at a National Tertiary Referral Centre for spinal trauma and spinal cord injuries, serving a catchment area of 5 million people. This study will follow patients undergoing posterior stabilisation of the upper spine using the SYMPHONY™ OCT system as an augment to fusion. This system consists of bone anchors (e.g. screws) for connection by longitudinal components (e.g. rods) via an interconnection mechanism (e.g., set screws) with optional transverse connectors (e.g., cross connectors) to link longitudinal components for additional stability during fusion mass development.

In spine fusion procedures, bone is encouraged to grow in order to fuse vertebrae of the spine together to relieve pain or increase stability. The likelihood of a successful fusion is thought to be influenced by multiple factors. Patient-related factors influencing fusion success include comorbidities such as osteoporosis or osteopenia, diabetes, and obesity. Factors affecting the inflammatory response, such as rheumatoid arthritis or long-term steroid use may also increase the likelihood of fusion failure. Fusion success can also be influenced by age, frailty, functional status, history of smoking or steroid use.

Frailty is a clinically recognizable syndrome comprised of declining physiological reserve, characterized by decreased resilience to adverse health outcomes. Fried et al have defined frailty as meeting three out of five of the following criteria: low grip strength, low energy, slow walking speed, low physical activity, unintentional weight loss. The modified 5-item frailty index (mFI-5) is another method of measuring frailty commonly used in clinical settings. It has been shown to predict the occurrence of adverse outcomes following various orthopaedic surgeries. The five comorbidities included in the mFI-5 are a history of hypertension, COPD, diabetes mellitus, congestive heart failure, and a non-independent functional status.

This pilot study hypothesizes that the use of SYMPHONY™ OCT System to treat upper spine instabilities will achieve results comparable to historical cases using the Mountaineer performed until 2021.

Inclusion criteria

• Consenting patients presenting for the treatment of acute and chronic instabilities of the craniocervical junction, the cervical and upper thoracic spine for whom the SYMPHONY OCT System is a suitable choice will be included in this study.
• Patients undergoing surgical treatment for upper cervical spine traumatic spinal fractures and/or traumatic dislocations, failed previous fusions (pseudarthrosis) and tumours involving the cervical/thoracic spine will be included in this study.

Exclusion criteria

• Non-surgical candidates, patients with contraindications to surgery (e.g. severe medical comorbidities, known infection, etc.),
• Patients with established osteoporosis
• Long-term, systemic steroid use
• Systemic diseases (e.g. rheumatoid arthritis, AIDS, HIV, etc.),
• Patients unwilling or unable to give informed consent, or patients unwilling or unable to complete Health-related quality of (HRQOL) outcome life measures at the specified study time points pre- and post-operatively.
• Subjects who have a history of drug or alcohol use that, in the opinion of the investigator would interfere with adherence to study requirements.