An observational study in Cervical Degenerative Disc Disorder, sponsored by NuVasive. Completed at 18 sites in United States. Per ClinicalTrials.gov, last updated 2026-01-08.
Sponsored by NuVasive · Observational
This study is intended to demonstrate the 5-year long-term safety and efficacy of the Simplify® Cervical Artificial Disc ("Simplify Disc") in subjects enrolled in the non-randomized two-level Simplify Disc Investigational Device Exemption (IDE) study. This study was conducted under IDE G150206
NuVasive is the lead sponsor of 38 studies on the registry; 8 are open to participants now.
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The study population will include subjects who were enrolled in the IDE study G150206. This will include up to 170 subjects eligible for study enrollment from sixteen (16) sites in the two level Simplify Disc IDE study who consent to long-term follow-up. Additionally, up to 17 training subjects from the two level Simplify Disc IDE study from seventeen (17) sites will be enrolled.
- All subjects enrolled in the two level Simplify Disc IDE study are considered for this long-term follow-up study.
Exclusion Criteria:
Extended follow-up of IDE Subjects treated at two continuous levels with the Simplify Cervical Artificial Disc during IDE G150206
Device: Simplify Disc
This study used a non-concurrent historical control with subject-level data on a parallel group design. The historical control group was formed from the randomized ACDF arm of a previously completed two level cervical disc trial.
The Simplify Disc is a cervical artificial disc manufactured from polyether ether ketone (PEEK) endplates and a mobile, zirconia-toughened alumina ceramic core.
Clinical Composite Success
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."
Time frame: Data through 24 months gathered in IDE (NCT03123549; start date 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-op. Comparison data from historical controls up to 60 months post-op is also reported
Clinically Significant Improvement in One or More Radicular Symptoms or Myelopathy
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)
Time frame: Data through 24 months gathered in IDE (NCT03123549; start date 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-op. Comparison data from historical controls up to 60 months post-op is also reported
Health Survey; 36-Item Short Form Survey (SF-36) - Physical Component Score (PCS) Maintenance or Improvement
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549; start date 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-op. Comparison data from historical controls up to 60 months post-op is also reported
Health Survey; 36-Item Short Form Survey (SF-36) - Mental Component Score (MCS) Maintenance or Improvement
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549; start date 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-op. Comparison data from historical controls up to 60 months post-op is also reported
Dysphagia Handicap Index (DHI Scale)
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549 with start date of 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-operative.
Patient Satisfaction
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549; start date 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-op. Comparison data from historical controls up to 60 months post-op is also reported
Physician's Perception
Results at 60 months were categorized by the physician's perception of the subject's condition (excellent, good, fair, or poor).
Time frame: Data through 24 months gathered in IDE (NCT03123549; start date 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-op. Comparison data from historical controls up to 60 months post-op is also reported
Change in Average Disc Height (Superior Index Level)
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549 with start date of 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-operative.
Change in Average Disc Height (Inferior Index Level)
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549 with start date of 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-operative.
Adjacent Level Deterioration - Superior Adjacent Level
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549 with start date of 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-operative.
Adjacent Level Deterioration - Inferior Adjacent Level
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549 with start date of 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-operative.
Displacement or Migration of the Device
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.
Time frame: Data through 24 months gathered in IDE (NCT03123549; start date 4/1/17). This PAS (start date 8/1/21) followed the same patient cohort through 60 months post-op. Comparison data from historical controls up to 60 months post-op is also reported
No recruitment - long term follow up of subjects previously enrolled in Investigational Device Exemption (IDE) and historical control data
| Milestone | Simplify Disc | Historical ACDF Control |
|---|---|---|
| Started | 157 | 134 |
| Completed | 144 | 107 |
| Not completed | 13 | 27 |
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."
| Participants | Simplify Disc | ACDF: Historical ACDF control data |
|---|---|---|
| Clinical Composite Success | 127 | 84 |
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)
| Participants | Simplify Disc | ACDF: Historical ACDF control data |
|---|---|---|
| Clinically Significant Improvement in One or More Radicular Symptoms or Myelopathy | 125 | 90 |
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.
| Participants | Simplify Disc | ACDF: Historical ACDF control data |
|---|---|---|
| Maintenance or improvement | 122 | 86 |
| Absence of maintenance or improvement | 13 | 18 |
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.
| Participants | Simplify Disc | ACDF: Historical ACDF control data |
|---|---|---|
| Maintenance or improvement | 110 | 80 |
| Absence of maintenance or improvement | 25 | 24 |
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.
| score on a scale | Simplify Disc |
|---|---|
| Dysphagia Handicap Index (DHI Scale) | 7.1 ± 11.6 |
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.
| Participants | Simplify Disc | ACDF: Historical ACDF control data |
|---|---|---|
| Definitely true | 116 | 77 |
| Mostly true | 22 | 24 |
| Don't know | 3 | 4 |
| Mostly false | 2 | 1 |
| Definitely false | 0 | 1 |
Results at 60 months were categorized by the physician's perception of the subject's condition (excellent, good, fair, or poor).
| Participants | Simplify Disc | ACDF: Historical ACDF control data |
|---|---|---|
| Excellent | 126 | 57 |
| Good | 10 | 41 |
| Fair | 5 | 8 |
| Poor | 0 | 1 |
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.
| mm | Simplify Disc |
|---|---|
| Change in Average Disc Height (Superior Index Level) | 1.10 ± 0.84 |
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.
| mm | Simplify Disc |
|---|---|
| Change in Average Disc Height (Inferior Index Level) | 0.81 ± 0.94 |
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.
| Participants | Simplify Disc |
|---|---|
| None | 70 |
| Doubtful | 41 |
| Minimal | 20 |
| Moderate | 5 |
| Severe | 1 |
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.
| Participants | Simplify Disc |
|---|---|
| None | 81 |
| Doubtful | 23 |
| Minimal | 13 |
| Moderate | 5 |
| Severe | 2 |
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.
| Participants | Simplify Disc | ACDF: Historical ACDF control data |
|---|---|---|
| Migration present at either index level | 0 | 0 |
| Migration absent at both index levels | 140 | 102 |
Collected over Data presented includes adverse events (AEs) collected under both the parent IDE study (G150206) and this Post Approval Study (PAS) for patients who enrolled in this PAS. Data collected from the time of surgery through 24 months was gathered in the IDE (NCT03123549; start date 4/1/17) and data for the same patient cohort from 24 months through 60 months post-op was gather under this PAS (start date 8/1/21). Comparison data from historical controls through 60 months post-op is also reported. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Simplify Disc | 0/157 (0%) | 40/157 (25.5%) | 119/157 (75.8%) |
| ACDF: Historical ACDF Control Data | 0/134 (0%) | 54/134 (40.3%) | 126/134 (94%) |
| Event | Simplify Disc | ACDF: Historical ACDF Control Data |
|---|---|---|
| Lumbar radiculopathyMusculoskeletal and connective tissue disorders | 13/157 | 14/134 |
| Appendicular arthritisMusculoskeletal and connective tissue disorders | 3/157 | 6/134 |
| Infection (not at surgical site)Infections and infestations | 7/157 | 2/134 |
| Low back painMusculoskeletal and connective tissue disorders | 1/157 | 5/134 |
| Nonunion/pseudoarthrosisMusculoskeletal and connective tissue disorders | 0/157 | 5/134 |
| OtherGeneral disorders | 2/157 | 4/134 |
| CancerNeoplasms benign, malignant and unspecified (incl cysts and polyps) | 3/157 | 3/134 |
| DysphagiaGastrointestinal disorders | 2/157 | 3/134 |
| Psychological illnessPsychiatric disorders | 0/157 | 3/134 |
| Accidental traumaGeneral disorders | 3/157 | 2/134 |
| Event | Simplify Disc | ACDF: Historical ACDF Control Data |
|---|---|---|
| Accidental traumaGeneral disorders | 27/157 | 39/134 |
| Pain (no narcotic given)General disorders | 32/157 | 37/134 |
| Appendicular arthritisMusculoskeletal and connective tissue disorders | 11/157 | 32/134 |
| InflammationGeneral disorders | 30/157 | 29/134 |
| Cervical radiculopathyMusculoskeletal and connective tissue disorders | 29/157 | 29/134 |
| Lumbar radiculopathyMusculoskeletal and connective tissue disorders | 30/157 | 28/134 |
| HeadacheGeneral disorders | 8/157 | 23/134 |
| Gastrointestinal complicationsGastrointestinal disorders | 6/157 | 21/134 |
| Compressive neuropathyNervous system disorders | 18/157 | 20/134 |
| OtherGeneral disorders | 11/157 | 19/134 |
| Age, Continuous(years) | Simplify Disc | Historical ACDF Control | Total |
|---|---|---|---|
| Mean | 49.35 ± 9.04 | 47.71 ± 7.83 | 48.59 ± 8.48 |
| Sex: Female, Male(Participants) | Simplify Disc | Historical ACDF Control | Total |
|---|---|---|---|
| Female | 83 | 71 | 154 |
| Male | 74 | 63 | 137 |
| Race (NIH/OMB)(Participants) | Simplify Disc | Historical ACDF Control | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 1 | 3 | 4 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 5 | 6 | 11 |
| White | 146 | 122 | 268 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 5 | 3 | 8 |
| Region of Enrollment(Participants) | Simplify Disc | Historical ACDF Control | Total |
|---|---|---|---|
| United States | 157 | 134 | 291 |
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