Trial Outcomes & Findings for Investigation of the Two Level Simplify® Cervical Artificial Disc (NCT NCT03123549)

Last Updated: 2026-01-08

Results Overview

Individual success is defined as at least a 15 point improvement in Neck Disability Index (NDI) Score at 24 months compared with baseline, maintenance or improvement in neurologic status at 24 months compared with baseline, no additional surgical procedure at the index level within 24 months, and the absence of a serious adverse event classified as implant-associated or implant/surgical procedure-associated within 24 months. NDI scale is reported in a range from 0 - 100, with 0 consistent with best ability to function and 100 with worst ability to function.

Recruitment status

COMPLETED

Study phase

Target enrollment

182 participants

Primary outcome timeframe

24 Months

Results posted on

2026-01-08

Participant Flow

Historical control was used for control arm. The only subjects enrolled under this study were investigational subjects (Simplify Disc).

Participant milestones

Participant milestones
Measure	Simplify Disc Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine	Historical Control - Anterior Cervical Discectomy and Fusion (ACDF) This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.
Overall Study STARTED	182	170
Overall Study COMPLETED	168	127
Overall Study NOT COMPLETED	14	43

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Ethnicity data not captured for historical control group.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Simplify Disc n=182 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine	Historical Control n=170 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Total n=352 Participants Total of all reporting groups
Age, Continuous	49.25 years STANDARD_DEVIATION 9.39 • n=182 Participants	47.45 years STANDARD_DEVIATION 7.89 • n=170 Participants	48.38 years STANDARD_DEVIATION 8.70 • n=352 Participants
Sex: Female, Male Female	95 Participants n=182 Participants	89 Participants n=170 Participants	184 Participants n=352 Participants
Sex: Female, Male Male	87 Participants n=182 Participants	81 Participants n=170 Participants	168 Participants n=352 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	5 Participants n=182 Participants • Ethnicity data not captured for historical control group.	—	5 Participants n=182 Participants • Ethnicity data not captured for historical control group.
Ethnicity (NIH/OMB) Not Hispanic or Latino	177 Participants n=182 Participants • Ethnicity data not captured for historical control group.	—	177 Participants n=182 Participants • Ethnicity data not captured for historical control group.
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=182 Participants • Ethnicity data not captured for historical control group.	—	0 Participants n=182 Participants • Ethnicity data not captured for historical control group.
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=182 Participants	0 Participants n=170 Participants	0 Participants n=352 Participants
Race (NIH/OMB) Asian	1 Participants n=182 Participants	3 Participants n=170 Participants	4 Participants n=352 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=182 Participants	0 Participants n=170 Participants	0 Participants n=352 Participants
Race (NIH/OMB) Black or African American	6 Participants n=182 Participants	6 Participants n=170 Participants	12 Participants n=352 Participants
Race (NIH/OMB) White	170 Participants n=182 Participants	157 Participants n=170 Participants	327 Participants n=352 Participants
Race (NIH/OMB) More than one race	0 Participants n=182 Participants	0 Participants n=170 Participants	0 Participants n=352 Participants
Race (NIH/OMB) Unknown or Not Reported	5 Participants n=182 Participants	4 Participants n=170 Participants	9 Participants n=352 Participants
Region of Enrollment United States	182 participants n=182 Participants	170 participants n=170 Participants	352 participants n=352 Participants

PRIMARY outcome

Timeframe: 24 Months

Population: While 168 Simplify Disc subjects and 127 historical control subjects were considered completers for subject accounting purposes, 173 (Simplify Disc) and 145 (ACDF) subjects were evaluable for composite clinical success. This is due to the fact that some subjects were known failures prior to the 24-month visit.

Outcome measures

Outcome measures
Measure	Historical Control n=145 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=173 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Composite Clinical Success (CCS) Rate of the Simplify® Disc	105 Participants	153 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos

Population: While 127 historical control subjects were considered completers for subject accounting purposes, 128 historical subjects had sufficient neurological data available for CEC determination of maintenance or improvement of neurological status.

Neurological success was defined as maintenance or improvement in neurologic status at Month 24 as compared to baseline, as determined by the independent Clinical Events Committee (CEC). The CEC reviews neurological exams of motor, sensory, reflex, and myelopathic gait to make an adjudication determination.

Outcome measures

Outcome measures
Measure	Historical Control n=128 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=168 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Neurological Status Improved	106 Participants	140 Participants
Neurological Status Maintained	19 Participants	28 Participants
Neurological Status Deteriorated	3 Participants	0 Participants

SECONDARY outcome

Timeframe: Baseline, 3mos

Population: While 168 Simplify Disc subjects and 127 historical control subjects were considered completers for subject accounting purposes at 24 months, 177 (Simplify Disc) and 154 (ACDF) subjects had evaluable change in NDI scores at 3 months.

Time to recovery is defined as time to first 15-point improvement in NDI NDI scale is reported in a range from 0 - 100, with 0 consistent with best ability to function and 100 with worst ability to function.

Outcome measures

Outcome measures
Measure	Historical Control n=154 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=177 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Number of Subjects With 15-point Improvement in NDI at 3 Months (Time to Recovery) 15-Point Improvement (Yes)	123 Participants	160 Participants
Number of Subjects With 15-point Improvement in NDI at 3 Months (Time to Recovery) 15-Point Improvement (No)	31 Participants	17 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 158 Simplify Disc subjects had change in Neck Pain Intensity data at 24 months due to missed questionnaires.

Changes of at least 2 points on a 10-point scale will be regarded as clinically significant (0=no pain; 10=worst pain)

Outcome measures

Outcome measures
Measure	Historical Control n=127 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=158 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Neck Pain Intensity Questionnaire Success	110 Participants	147 Participants
Neck Pain Intensity Questionnaire Fail	17 Participants	11 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 158 Simplify Disc subjects had change in Arm Pain Intensity data at 24 months due to missed questionnaires.

Changes of at least 2 points on a 10-point scale will be regarded as clinically significant (0=no pain; 10=worst pain)

Outcome measures

Outcome measures
Measure	Historical Control n=127 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=158 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Arm Pain Intensity Questionnaire Failure	19 Participants	16 Participants
Arm Pain Intensity Questionnaire Success	108 Participants	142 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects and 127 historical control subjects were considered completers for subject accounting purposes, 172 (Simplify Disc) and 145 (ACDF) subjects had evaluable treatment satisfaction data at 24 months.

Question 1 - "I am satisfied with the results of my surgery" was compared between groups at Month 24. Answer options ranged from definitely true to definitely false.

Outcome measures

Outcome measures
Measure	Historical Control n=145 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=172 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Patient Questionnaires- Treatment Satisfaction Survey Definitely true	99 Participants	131 Participants
Patient Questionnaires- Treatment Satisfaction Survey Mostly true	30 Participants	26 Participants
Patient Questionnaires- Treatment Satisfaction Survey Definitely false	5 Participants	2 Participants
Patient Questionnaires- Treatment Satisfaction Survey Don't know	7 Participants	8 Participants
Patient Questionnaires- Treatment Satisfaction Survey Mostly false	4 Participants	5 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 158 Simplify Disc subjects had SF-36 data available at 24 months due to missed questionnaires.

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.

Outcome measures

Outcome measures
Measure	Historical Control n=127 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=158 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
SF-36v2 Health Survey Physical Component Score (PCS) Maintenance or Improvement Maintenance or improvement	114 Participants	146 Participants
SF-36v2 Health Survey Physical Component Score (PCS) Maintenance or Improvement Absence of maintenance or improvement	13 Participants	12 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 158 Simplify Disc subjects had SF-36 data available at 24 months due to missed questionnaires.

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 MCS(Postop) - MCS(Preop) ≥0.

Outcome measures

Outcome measures
Measure	Historical Control n=127 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=158 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
SF-36 Mental Component Score (MCS) Maintenance or Improvement Maintenance or improvement	94 Participants	125 Participants
SF-36 Mental Component Score (MCS) Maintenance or Improvement Absence of maintenance or improvement	33 Participants	33 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Dysphagia Handicap Index (DHI scale) for the investigational Simplify® Disc at 24 months compared to baseline. 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.

Outcome measures

Outcome measures
Measure	Historical Control This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=167 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Dysphagia Handicap Index (DHI)	—	6.9 score on a scale Standard Deviation 10.7

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects and 127 historical control subjects were considered completers for subject accounting purposes, 170 (Simplify Disc) and 145 (ACDF) subjects had evaluable Physician's Perception of Results data at 24 months.

Results at 24 months for the investigational Simplify® Disc and at 24 months for the control ACDF will also be categorized by the physician according to their perception of the results. Available responses include excellent, good, fair, and poor. Maintenance or improvement was defined as either maintenance of the assigned preoperative grade or any shift to a more favorable grade postoperatively (e.g. poor to fair, fair to good).

Outcome measures

Outcome measures
Measure	Historical Control n=145 Participants This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=170 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Physician's Perception of Results Excellent	85 Participants	139 Participants
Physician's Perception of Results Good	42 Participants	26 Participants
Physician's Perception of Results Fair	15 Participants	3 Participants
Physician's Perception of Results Poor	3 Participants	2 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 164 Simplify Disc subjects had evaluable radiographs for this assessment at 24 months due to missed x-rays or poor image quality which limited analysis.

Average disc height (superior index level) at 24 months was compared to the baseline measurement and the change was calculated. Measurements were scored by an independent core lab. Average disc height is calculated as the simple average of the anterior and posterior disc heights. Data was not collected on disc height in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

Outcome measures

Outcome measures
Measure	Historical Control This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=164 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Change in Average Disc Height (Superior Index Level)	—	1.19 mm Standard Deviation 0.81

SECONDARY outcome

Timeframe: Baseline, 24M

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 157 Simplify Disc subjects had evaluable radiographs for this assessment at 24 months due to missed x-rays or poor image quality which limited analysis.

Average disc height (inferior index level) at 24 months was compared to the baseline measurement and the change was calculated. Measurements were scored by an independent core lab. Average disc height is calculated as the simple average of the anterior and posterior disc heights. Data was not collected on disc height in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

Outcome measures

Outcome measures
Measure	Historical Control This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=157 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Change in Average Disc Height (Inferior Index Level)	—	0.84 mm Standard Deviation 0.96

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 166 Simplify Disc subjects had evaluable radiographs for this assessment at 24 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), severe (Large osteophytes, marked sclerosis of vertebral plates, and marked narrowing of disk space), indeterminate, or unable to assess. Data was not collected on ALDD in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

Outcome measures

Outcome measures
Measure	Historical Control This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=166 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Superior Adjacent Level Disc Degeneration (ALDD) Minimal	—	16 Participants
Superior Adjacent Level Disc Degeneration (ALDD) None	—	100 Participants
Superior Adjacent Level Disc Degeneration (ALDD) Doubtful	—	45 Participants
Superior Adjacent Level Disc Degeneration (ALDD) Moderate	—	2 Participants
Superior Adjacent Level Disc Degeneration (ALDD) Severe	—	1 Participants
Superior Adjacent Level Disc Degeneration (ALDD) Indeterminate	—	0 Participants
Superior Adjacent Level Disc Degeneration (ALDD) Unable to assess	—	2 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

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), severe (Large osteophytes, marked sclerosis of vertebral plates, and marked narrowing of disk space), indeterminate, or unable to assess. Data was not collected on ALDD in the historical ACDF control group. Only Simplify Disc subjects are reported. This was pre-specified in the study design.

Outcome measures

Outcome measures
Measure	Historical Control This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=166 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Inferior Adjacent Level Disc Degeneration (ALDD) None	—	110 Participants
Inferior Adjacent Level Disc Degeneration (ALDD) Doubtful	—	20 Participants
Inferior Adjacent Level Disc Degeneration (ALDD) Minimal	—	9 Participants
Inferior Adjacent Level Disc Degeneration (ALDD) Moderate	—	2 Participants
Inferior Adjacent Level Disc Degeneration (ALDD) Severe	—	1 Participants
Inferior Adjacent Level Disc Degeneration (ALDD) Indeterminate	—	21 Participants
Inferior Adjacent Level Disc Degeneration (ALDD) Unable to assess	—	3 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Population: While 168 Simplify Disc subjects were considered completers for subject accounting purposes, 166 Simplify Disc subjects had an evaluable MRI for this assessment at 24 months due to missed MRIs.

Facet degeneration was assessed using MRI for the investigational Simplify Disc at 24 months compared to baseline. Degeneration was graded as none (normal facet joint space), mild (narrowing of the facet joint space and / or small osteophytes and / or mild hypertrophy of the articular process), moderate (narrowing of the facet joint space and/or moderate osteophytes and/or moderate hypertrophy of the articular process and / or mild subarticular bone erosions), severe (Narrowing of the facet joint space and/or large osteophytes and/or severe hypertrophy of the articular process and/or severe subarticular bone erosions and/or subchondral cysts), indeterminate, or unable to assess. Facet degeneration was not assessed in the ACDF historical control group, as there is no 24 month MRI. This was pre-specified in the study design.

Outcome measures

Outcome measures
Measure	Historical Control This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=166 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Facet Degeneration (Superior Index Level) None	—	87 Participants
Facet Degeneration (Superior Index Level) Mild	—	64 Participants
Facet Degeneration (Superior Index Level) Moderate	—	13 Participants
Facet Degeneration (Superior Index Level) Severe	—	0 Participants
Facet Degeneration (Superior Index Level) Indeterminate	—	0 Participants
Facet Degeneration (Superior Index Level) Unable to assess	—	2 Participants

SECONDARY outcome

Timeframe: Baseline, 24mos.

Outcome measures

Outcome measures
Measure	Historical Control This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm of a previously completed two level cervical disc trial.	Simplify Disc n=166 Participants Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine
Facet Degeneration (Inferior Index Level) None	—	96 Participants
Facet Degeneration (Inferior Index Level) Mild	—	60 Participants
Facet Degeneration (Inferior Index Level) Moderate	—	8 Participants
Facet Degeneration (Inferior Index Level) Severe	—	0 Participants
Facet Degeneration (Inferior Index Level) Indeterminate	—	0 Participants
Facet Degeneration (Inferior Index Level) Unable to assess	—	2 Participants

Adverse Events

Simplify Disc

Serious events: 32 serious events

Other events: 96 other events

Deaths: 2 deaths

Historical Control - Anterior Cervical Discectomy and Fusion (ACDF)

Serious events: 62 serious events

Other events: 145 other events

Deaths: 1 deaths

Serious adverse events

Other adverse events

Additional Information

Jessica Fulwider

NuVasive, Inc.

Phone: 7037721455

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Measure	Simplify Disc n=182 participants at risk Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine	Historical Control - Anterior Cervical Discectomy and Fusion (ACDF) n=170 participants at risk This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm (N=188) of a previously completed two level cervical disc trial.
Infections and infestations Infection (all other infections-NOT at cervical surgical site)	3.3% 6/182 • Number of events 7 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	1.2% 2/170 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Vascular disorders Hematoma or seroma	1.1% 2/182 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.00% 0/170 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Injury, poisoning and procedural complications Accidental trauma	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	2.4% 4/170 • Number of events 4 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Low back pain (no narcotic given)	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	3.5% 6/170 • Number of events 6 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Vascular disorders Embolism	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Appendicular arthritis	0.55% 1/182 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	2.4% 4/170 • Number of events 4 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Cervical Radiculopathy	2.2% 4/182 • Number of events 4 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	2.4% 4/170 • Number of events 5 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Lumbar Radiculopathy	4.4% 8/182 • Number of events 8 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	7.6% 13/170 • Number of events 14 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Pain (no narcotic given)	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Injury, poisoning and procedural complications Vertebral fracture	1.1% 2/182 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.00% 0/170 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Endocrine disorders Other	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.00% 0/170 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Gastrointestinal disorders Gastrointestinal complications including ileus, nausea and vomiting	1.1% 2/182 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	2.9% 5/170 • Number of events 5 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Injury, poisoning and procedural complications Blood loss (greater than 500ml)	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.00% 0/170 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Cancer	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	1.2% 2/170 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Renal and urinary disorders Difficulty with urination	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	1.2% 2/170 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Gastrointestinal disorders Dysphagia	1.1% 2/182 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	1.8% 3/170 • Number of events 3 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Vascular disorders Hypertension	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.00% 0/170 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Pain (narcotic given)	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	1.2% 2/170 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Injury, poisoning and procedural complications Cerebrospinal fluid leakage	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Development of DDD at adjacent levels	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Injury, poisoning and procedural complications Dural injury	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Respiratory, thoracic and mediastinal disorders Atelectasis	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Psychiatric disorders Psychological Illness	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	1.2% 2/170 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Soft tissue damage	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Skin and subcutaneous tissue disorders Dermatitis/Skin allergy	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Low back pain (narcotic given)	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	1.2% 2/170 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Respiratory, thoracic and mediastinal disorders Sleep apnea	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Renal and urinary disorders Renal dysfunction	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Nonunion/pseudoarthrosis	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	5.9% 10/170 • Number of events 10 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Inflammation	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Implant collapse or subsidence	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Respiratory, thoracic and mediastinal disorders Pneumonia	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Spondylosis acquista	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Vascular disorders Thrombosis	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Reproductive system and breast disorders Other	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Injury, poisoning and procedural complications Other	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Metabolism and nutrition disorders Other	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Cardiac disorders Cardiac Event	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Vascular disorders Stroke	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	0.59% 1/170 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.

Measure	Simplify Disc n=182 participants at risk Simplify Disc at two levels of the cervical spine Simplify Disc: Simplify Disc at two levels of the cervical spine	Historical Control - Anterior Cervical Discectomy and Fusion (ACDF) n=170 participants at risk This study will utilize a non-concurrent historical control with subject-level data on a parallel group design. The historical control group will be formed from the randomized ACDF arm (N=188) of a previously completed two level cervical disc trial.
Gastrointestinal disorders Gastrointestinal complications including ileus, nausea and vomiting	2.7% 5/182 • Number of events 5 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	7.1% 12/170 • Number of events 17 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Development of DDD at adjacent levels	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	5.3% 9/170 • Number of events 9 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Gastrointestinal disorders Dysphagia	2.7% 5/182 • Number of events 5 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	8.2% 14/170 • Number of events 14 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Nervous system disorders Headache	4.9% 9/182 • Number of events 9 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	13.5% 23/170 • Number of events 24 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Pain (narcotic given)	2.7% 5/182 • Number of events 5 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	7.1% 12/170 • Number of events 12 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Spasm	1.6% 3/182 • Number of events 3 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	6.5% 11/170 • Number of events 13 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Neck Stiffness	0.00% 0/182 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	5.3% 9/170 • Number of events 9 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Infections and infestations Infection (all other infections-NOT at cervical surgical site)	5.5% 10/182 • Number of events 12 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	10.6% 18/170 • Number of events 20 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Injury, poisoning and procedural complications Accidental trauma	9.9% 18/182 • Number of events 20 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	21.8% 37/170 • Number of events 42 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Skin and subcutaneous tissue disorders Dermatitis/Skin allergy	1.1% 2/182 • Number of events 2 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	5.3% 9/170 • Number of events 9 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Low back pain (narcotic given)	0.55% 1/182 • Number of events 1 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	6.5% 11/170 • Number of events 11 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Appendicular arthritis	2.7% 5/182 • Number of events 5 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	14.7% 25/170 • Number of events 30 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Cervical Radiculopathy	12.1% 22/182 • Number of events 26 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	18.2% 31/170 • Number of events 34 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Inflammation	11.5% 21/182 • Number of events 23 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	17.6% 30/170 • Number of events 34 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Lumbar Radiculopathy	9.9% 18/182 • Number of events 18 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	9.4% 16/170 • Number of events 16 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Nervous system disorders Numbness - increased from pre-op or prior visit	2.2% 4/182 • Number of events 4 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	8.2% 14/170 • Number of events 14 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Musculoskeletal and connective tissue disorders Pain (no narcotic given)	12.1% 22/182 • Number of events 24 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	20.0% 34/170 • Number of events 38 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.
Nervous system disorders Compressive Neuropathy	6.6% 12/182 • Number of events 12 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.	10.6% 18/170 • Number of events 18 • Adverse events were collected continuously throughout study follow-up period. Results are reported through study day 790.