To demonstrate that DDD patients operated for spondylolisthesis fare equally well regardless of the surgical procedure (anterolateral or posterior) performed as measured by the change of ODI at 3 months as compared to baseline.

ODI=Oswestry Disability Scale [0-100]; higher scores mean a worse outcome Timepoints: Baseline and 3 months

227 participants with spondylolisthesis were categorized into either ANT or POST groups, depending on the type of MI lumbar surgery received. n=206 of these patients completed the 3-month follow-up visit.

To evaluate whether DDD patients without spondylolisthesis fare equally well regardless of the surgical procedure (anterolateral or posterior) performed, as measured by Oswestry Disability Index (ODI) at 3 months. Scored [0-100]; higher scores mean a worse outcome Timepoints: Baseline and 3 months

n=100 patients without spondylolisthesis completed the 3-month follow up, out of a total of n=110 non-spondilolisthesis patients enrolled

To observe the change in ODI scores as compared to baseline through 5 years. The score at baseline gives the baseline score [0-100]; the higher the score, the worse the outcome. Additional scores are based on the change from baseline. The higher the score, the greater the improvement.

Timepoints: Baseline, 4 weeks, 3 months, 1-,2-,3-,4-, and 5-years

Participant numbers may deviate per follow-up visit due to data not having been completed for a number of participants (e.g. data not completed by follow-up, drop-out)

To observe a change in VAS back pain as compared to baseline through 5 years. At baseline scored on a scale from [0-10]; 0 = No pain 10= Worst pain possible.

Timepoints: Baseline, 4 weeks, 3 months, 1-,2-,3-,4-, and 5-years

Participant numbers may differ at follow-up time points due to data not being available for some (e.g. participant did not complete the data, or drop-out)

To observe the change in VAS leg pain as compared to baseline through 5 years. The score at baseline gives the baseline score [0-10]; 0 = No pain 10= Worst pain possible.

Timepoints: Baseline, 4 weeks, 3 months, 1-,2-,3-,4-, and 5-years

Number of participants may differ as data is not always available for all (e.g. data not completed by participant, drop-out)

To observe the change in EuroQol-5 Dimension (EQ-5D) index score as compared to baseline through 5 years. Scored from [-0.109 to 1]. A higher score means a better outcome.

Timepoints: Baseline, 4 weeks, 3 months, 1-,2-,3-,4-, and 5-years

Number of participants may differ as data is not always available for all (e.g. data not completed by participant, drop-out)

Neurological status is based on four types of measurements (sections): motor, sensory, reflexes, and straight leg raising.

Overall neurological success is defined as maintenance or improvement in all sections (motor, sensory, reflex, and straight leg raising) for the time period evaluated. In order for a section to be considered a success, each element in the section must remain the same or improve from the time of the baseline evaluation to the time period evaluated. Therefore, if any one element in any section does not stay the same or improve, then a patient was not considered a success for neurological status.

Fusion success rate was summarized for at 1, 2, 3, 4, 5 year follow-up. If a participant showed fusion success at early time points and non-fusion at a later time point, the fusion status at all earlier points was considered as non-fusion. For 2-level fusion participants, fusion success was defined as achieving fusion at both treated levels.

Fusion assessments weren't conducted at each time point for each participant, and not all participants had their fusion status assessed, hence the participant numbers are different at each time point.

To document Secondary Surgeries at index and/or adjacent level(s)throughout the study. When a participant requires additional surgery at the index level(s), it can be an indicator of insufficient outcomes of the initial surgery. Due to the progressive nature of the degenerative lumbar spine, additional surgeries at the index and/or adjacent levels might be required after the initial surgery. To ensure all safety and economic values are collected, the revision surgeries and their complication types and rates will be assessed during the study by the surgeons.

For secondary surgery at index levels and/or secondary surgery at adjacent levels, survival analysis was performed to estimate the cumulative event rate up to 5 years.

Not all participants had additional surgery, and some participants had multiple revision surgeries. In the ANT group n=16 participants who had at least 1 revision surgery, in the POST group n=21.

Document Adverse Events occurrence throughout the study

To observe and document the days needed for participants to get out of bed and ambulate with or without assistance. Time range: [0-11] days

For two participants in the ANT arm, no data was available for "Time needed for first ambulation"

To observe and document the days after the surgery, fulfilling following criteria:

• No need for intravenous infusion of analgesic drugs
• No ongoing surgery related adverse events impending discharge
• No need for nursing care

Timeframe: [0-46] days

The objective of the Surgery Recovery Day assessment is to collect the day when the participant could be discharged based on his actual clinical condition because the effective day of discharge may be prolonged by factors other than the participant's clinical recovery such as social factors or co-morbidity.

For the purpose of reporting these parameters the day of the surgery were considered 'D0', the first day after surgery as 'D1', the second day as 'D2' and so on.

Data for 1 participant in the ANT group is unavailable for "Surgery Recovery"

Healthcare utilization were measured with the following three costs components:

1. resources: surgery room, length of hospital stay, additional medical visits (outpatient consultations, visits to primary care services, etc)
2. medications
3. non-pharmacologic therapies: rehabilitation program

Not all data completed for each participant at each follow-up visit

Healthcare utilization is measured with the following three cost components:

1. resources: surgery room, length of hospital stay, additional medical visits (outpatient consultations, visits to primary care services, etc)
2. medications
3. non-pharmacologic therapies: rehabilitation program

Some questions were left blank by the sites.

Healthcare utilization is measured with the following three costs components:

1. resources: surgery room, length of hospital stay, additional medical visits (outpatient consultations, visits to primary care services, etc)
2. medications
3. non-pharmacologic therapies: rehabilitation program

Data was not always completed for each participant by the site

Healthcare utilization is measured with the following three cost components:

1. resources: surgery room, length of hospital stay, additional medical visits (outpatient consultations, visits to primary care services, etc)
2. medications
3. non-pharmacologic therapies: rehabilitation program

Some questions were left blank by the sites

Healthcare utilization is measured with the following three cost components:

1. resources: surgery room, length of hospital stay, additional medical visits (outpatient consultations, visits to primary care services, etc)
2. medications
3. non-pharmacologic therapies: rehabilitation program

Some questions were left blank by the sites

Healthcare utilization is measured with the following three cost components:

1. resources: surgery room, length of hospital stay, additional medical visits (outpatient consultations, visits to primary care services, etc)
2. medications
3. non-pharmacologic therapies: rehabilitation program

The minimum-maximum time spent at the hospital was [1-53 days]

Some questions were left blank by the sites

Healthcare utilization is measured with the following three cost components:

1. resources: surgery room, length of hospital stay, additional medical visits (outpatient consultations, visits to primary care services, etc)
2. medications
3. non-pharmacologic therapies: rehabilitation program

Some questions were left blank by the sites

To observe and document the patient profile when choosing a particular minimally invasive fusion procedure:

Baseline information is summarized for all DDD patients per surgical procedure (ALIF, OLIF, DLIF, PLIF, TLIF, MIDLF).

To observe and document the patient profile when choosing a particular minimally invasive fusion procedure:

Baseline information is summarized for all DDD patients per surgical procedure (ALIF, OLIF, DLIF, PLIF, TLIF, MIDLF).

To observe and document the patient profile when choosing a particular minimally invasive fusion procedure:

Baseline information is summarized for all DDD patients per surgical procedure (ALIF, OLIF, DLIF, PLIF, TLIF, MIDLF).

For one participant in the OLIF Arm/Group height wasn't provided on the eCRF

To observe and document the patient profile when choosing a particular minimally invasive fusion procedure:

Baseline information is summarized for all DDD patients per surgical procedure (ALIF, OLIF, DLIF, PLIF, TLIF, MIDLF).

To observe and document the patient profile when choosing a particular minimally invasive fusion procedure:

Baseline information is summarized for all DDD patients per surgical procedure (ALIF, OLIF, DLIF, PLIF, TLIF, MIDLF).

For one participant height wasn't provided on the eCRF, hence this data and the BMI calculation are not available for this participant.