Individual success for Simplify Disc was defined as follows:

• Neck Disability Index (NDI) score improvement of at least 15 points from pre-operative;
• Maintenance or improvement in neurological status;
• No serious adverse event classified as implant associated or implant/surgical procedure associated; and
• No additional surgical procedure classified as a "failure."

While 144 Simplify Disc subjects completed the 60-month visit, 140 Simplify Disc subjects had completed change in Neck Disability Index and neurologic data at 60 months due to missed questionnaires and/or neurologic exams.

An arm pain questionnaire was used to measure radicular symptoms and compare to baseline symptoms in the IDE study. Changes of at least 2 points on a 10-point scale were regarded as clinically significant (0=no pain; 10=worst pain)

While 144 Simplify Disc subjects completed the 60-month visit, 136 subjects had change in Arm Pain Intensity data at 60 months due to missed questionnaires. Likewise, 107 ACDF control subjects completed the 60-month visit, but 104 had change in Arm Pain Intensity data at 60 months.

The PCS is a sub-score of the SF-36. The SF-36 is a multipurpose survey with 36 questions. The questions were combined, scored, and weighted to create two scores that provide glimpses into mental and physical functioning and overall health-related quality-of-life. Higher scores indicate better outcomes. Scores range from 0-50. Maintenance or improvement was defined as PCS(Postop) - PCS(Preop) ≥0.

While 144 Simplify Disc subjects completed the 60-month visit, 135 Simplify Disc subjects had SF-36 data available at 60 months due to missed questionnaires. Likewise, 107 ACDF subjects completed the 60-month visit, but 104 had SF-36 data available at 60 months.

The MCS is a sub-score of the SF-36. The SF-36 is a multipurpose survey with 36 questions. The questions were combined, scored, and weighted to create two scores that provide glimpses into mental and physical functioning and overall health-related quality-of-life. Higher scores indicate better outcomes. Scores range from 0-50. Maintenance or improvement was defined as PCS(Postop) - PCS(Preop) ≥0.

While 144 Simplify Disc subjects completed the 60-month visit, 135 Simplify Disc subjects had SF-36 data available at 60 months due to missed questionnaires. Likewise, 107 ACDF subjects completed the 60-month visit, but 104 had SF-36 data available at 60 months.

Dysphagia Handicap Index score for the Simplify Disc subjects at 60 months. A higher score is indicative of a less desirable outcome. It is scored 0-100.

Data was not collected on DHI in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

Patient satisfaction was assessed by survey based on the response to the statement "I am satisfied with the results of my surgery" at 60 months. Answer options ranged from definitely true to definitely false.

While 144 Simplify Disc subjects completed the 60-month visit, 143 subjects had evaluable treatment satisfaction data at 60 months.

Results at 60 months were categorized by the physician's perception of the subject's condition (excellent, good, fair, or poor).

While 144 Simplify Disc subjects completed the 60-month visit, 141 subjects had evaluable Physician's Perception of Results data at 60 months due to missed questionnaires.

Average disc height (superior index level) at 60 months was compared to the baseline measurement in the IDE study and the change was calculated. Measurements were scored by an independent core lab. Average disc height was calculated as the simple average of the anterior and posterior disc heights.

Data was not collected on average disc height in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

While 144 Simplify Disc subjects completed the 60-month visit, 140 subjects had evaluable radiographs for this assessment at 60 months due to missed x-rays or poor image quality which limited analysis.

Average disc height (inferior index level) at 60 months was compared to the baseline measurement in the IDE study and the change was calculated. Measurements were scored by an independent core lab. Average disc height was calculated as the simple average of the anterior and posterior disc heights.

Data was not collected on average disc height in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

While 144 Simplify Disc subjects completed the 60-month visit, 131 subjects had evaluable radiographs for this assessment at 60 months due to missed x-rays or poor image quality which limited analysis.

Outcome reports the number and percentage of subjects with adjacent level disc degeneration (ALDD) above the index level based on X-ray images. Degeneration was graded as none (no degenerative changes), doubtful (Minimal osteophytosis only), minimal (Definite osteophytosis with some sclerosis of anterior part of vertebral plates), moderate (Marked osteophytosis and sclerosis of vertebral plates with slight narrowing of disk space), or severe (Large osteophytes, marked sclerosis of vertebral plates, and marked narrowing of disk space). Assessments were made by an independent core lab.

Data was not collected on adjacent level deterioration in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

While 144 Simplify Disc subjects completed the 60-month visit, 137 Simplify Disc subjects had evaluable radiographs for this assessment at 60 months due to missed x-rays or poor image quality which limited analysis.

Outcome reports the number and percentage of subjects with adjacent level disc degeneration (ALDD) below the index level based on X-ray images. Degeneration was graded as none (no degenerative changes), doubtful (Minimal osteophytosis only), minimal (Definite osteophytosis with some sclerosis of anterior part of vertebral plates), moderate (Marked osteophytosis and sclerosis of vertebral plates with slight narrowing of disk space), or severe (Large osteophytes, marked sclerosis of vertebral plates, and marked narrowing of disk space). Assessments were made by an independent core lab.

Data was not collected on adjacent level deterioration in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

While 144 Simplify Disc subjects completed the 60-month visit, 124 Simplify Disc subjects had evaluable radiographs for this assessment at 60 months due to missed x-rays or poor image quality which limited analysis.

Displacement or migration of the device at 60 months was be compared to immediate post-op data collected in the IDE study. This was be graded by the radiographic core lab. Migration was considered "present" if changes of >3mm were noted. The superior index level and inferior index level was assessed separately.

While 144 Simplify Disc subjects completed the 60-month visit, 140 subjects had evaluable radiographs for this assessment at 60 months due to missed x-rays or poor image quality which limited analysis. Likewise, 107 ACDF subjects completed the 60-month visit, but 102 had 60-month radiographs available for this assessments.