Evaluation of Symphony™ Posterior Cervical System for Surgical Treatment of Adult Cervical Deformity

Multi-center, prospective, non-randomized study to evaluate Symphony™ Posterior Cervical System in the setting of surgical treatment of adult cervical deformity.

Specific Aims:

* Evaluate outcomes for operative treatment of adult cervical deformity patients treated with posterior spinal fusion using SymphonyTM posterior cervical system at 6 weeks, 1 year, and 2 year follow up. Outcome metrics will include standardized patient reported outcome measures, radiographic analysis of deformity correction and spinal alignment.
* Evaluate rates and risk factors for perioperative complications and need for revision surgery at 6 weeks, 1 year, and 2 years postoperatively.
* Develop and validate a surgical invasiveness index for cervical deformity surgical procedures
* Validate the cervical deformity frailty index previously developed by the ISSG and further optimize this index
* Establish adult cervical deformity specific thresholds for minimal clinically important difference (MCID) for standard outcomes measures using a patient satisfaction anchor
* Develop a series of predictive models for adult cervical deformity surgery, including outcomes (e.g. overall change and achievement of MCID), occurrence of complications, and radiographic changes
* Assess the psychological impact of adult cervical deformity, how psychological measures change following surgical treatment, and whether there are correlations between baseline psychological factors and outcomes following surgery
* Assess baseline functional measures (e.g. grip strength) for adult cervical deformity patients presenting for surgery, assess how these functional measures change following surgery, and assess whether there are correlations between baseline functional measures and likelihood to improve following surgery
* Assess baseline narcotic use among adult cervical deformity patients presenting for surgery
* Assess changes in narcotic use from baseline to follow-up intervals after surgical treatment for adult cervical deformity
* Assess for correlations between narcotic use (baseline and follow-up) and outcomes following surgical treatment for adult cervical deformity
* Assess the impact of osteopenia and osteoporosis on patient frailty, complications, and maintenance of deformity correction
* Define clinical and demographic features of the population afflicted with cervical deformity (e.g., age, gender, comorbidities, disability, health-related quality of life)
* Assess for correlations between radiographic parameters and degree of disability/pain at baseline
* Assess and describe surgical strategies used to address cervical deformity
* Define complications and rates of complications (perioperative and delayed) associated with the surgical treatment of cervical deformity
* Assess the role/need for pre/post operative tracheostomy and PEG
* Evaluate and compare radiographic changes of sagittal spinal alignment (focal, regional, and global) and pelvic parameters pre and post cervical deformity surgery.
* Develop predictive formulas of post-operative alignments based on surgical techniques employed for correction
* Identify risk factors related to poor clinical outcomes
* Define potential impact of complications on clinical/radiographic outcomes
* Determine reoperation rates over two-year follow-up period
* Assess change in subaxial alignment after occiput to C2 fusion
* Assess the effect of C1-2 lordosis and C1-2 fusion on subaxial alignment and outcome
* Assess outcomes of long fusions involving the occiput related to head center of gravity and regional and global balance
* Assess outcomes of occipital-cervical-thoracic fusion on cervical alignment and global alignment
* Evaluate clinical outcomes (short- and long-term) following cervical deformity surgery
* Assess cost-effectiveness of adult cervical deformity surgery
* Correlate different measures of frailty, including Edmonton, CHSA, and ISSG.

Eligibility Criteria:
Inclusion Criteria:

1. ≥18 years old at time of treatment
2. Patient undergoing a posterior cervical instrumented fusion using the DePuy Synthes SymphonyTM OCT System for the treatment of adult cervical deformity, defined as any of below criteria:

   1. 10 degrees of overall cervical kyphosis (measured from C2-C7)
   2. 10 degrees of kyphosis across any 1 or 2 cervical segments
   3. 10 degrees of scoliosis
   4. C2-C7 SVA \>4cm
3. Plan for surgical correction of cervical deformity in the next 6 months
4. Willing to provide consent and complete study forms at baseline and follow-up intervals

Exclusion Criteria:

1. Active spine tumor or infection
2. Deformity due to acute trauma
3. Unwilling to provide consent or to complete study forms
4. Prisoner
5. Pregnant or immediate plans to get pregnant