The primary objective of the study is to access the short term recovery (from surgery to hospital discharge) since the minimally invasive lumbar fusion techniques are expected to be associated with immediate short-term benefits. Patients undergoing minimally invasive procedures are reported to recover earlier from surgery particularly with a shorter time to first ambulation and shorter discharge as compared to the standard open procedures.

Outcome measure timeframe for time from surgery to first ambulation is assessed up to hospital discharge as pts are all ambulated before discharge from the hospital.

Relief of Back Pain intensity at 12 months compared to the baseline using the Back Pain Intensity Score assessed on a 10 cm Visual Analog Scale (VAS).

The endpoint is the difference between baseline and 12 months of the patient's back-pain intensity score on a Visual Analogue Scale (VAS). A standardized visual analogue scale (0cm-10cm; with 0cm meaning 'no pain' and 10cm meaning 'worst possible pain') was used. Large values of the VAS score represent large degree of pain. Large (negative) change in VAS score (12 months - baseline) represents large relief of pain.

The number of analyzed at 12 months only included subjects who had available data.

Leg pain intensity (using VAS intensity score) as compared to baseline. Relief of Leg Pain intensity at 12 months compared to the baseline using the Back Pain Intensity Score assessed on a 10 cm Visual Analog Scale (VAS).

The endpoint is the difference between baseline and 12 months of the patient's leg-pain intensity score on a Visual Analogue Scale (VAS). A standardized visual analogue scale (0cm-10cm; with 0cm meaning 'no pain' and 10cm meaning 'worst possible pain') was used. Large values of the VAS score represent large degree of pain. Large (negative) change in VAS score (12 months - baseline) represents large relief of pain.

The number of analyzed at 12 months only included subjects who had available data.

EQ-5D questionnaire as compared to baseline measurement. EQ-5D Index was calculated based on answers provided in the questionnaire. Applicable to a wide range of health conditions and treatments, the EQ-5D provides a simple descriptive profile and a single index value for health status. The EQ-5D-3L consists of the EQ-5D-3L descriptive system and the EQ visual analogue scale (EQ VAS). The EQ-5D descriptive system comprises 5 dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 3 levels: no problems, some problems, extreme problems. The respondent is asked to indicate his/her health state by ticking in the box against the most appropriate statement in each of the 5 dimensions. EQ VAS records the respondent's self-rated health on a vertical 20 cm VAS where the endpoints are labelled 'Best imaginable health state' at the top and 'Worst imaginable health state' at the bottom, having numeric values of 100 and 0 respectively.

The number of analyzed at 12 months only included subjects who had available data.

Fusion rate as assessed by the CT Scan or X-Rays, in those sites where this assessment is standard of care.

One hundred and thirty one-level patients (=130 LEVELS) and 24 two-level patients (=48 LEVELS) were assessed for fusion at 12 months per CIP defined criteria.

The number of patients who utilized rehabilitation programs was documented (when required).

Proportion of the patients needing a second intervention at the treated level(s) (reoperation rates).

Proportion of the patients needing intervention at adjacent level(s).

Document the change in pain medication consumption one year after surgery , as compared with baseline. The endpoint is the number of participants taking pain medication at baseline and number of participants taking pain medication in the week before the 12 months follow up visit.

The number of analyzed at 12 months only included subjects who had available data.

Document the Adverse Events occurrence throughout the study. All adverse events have been included regardless visit windowing.

Oswestry Disability Index (ODI) 12 months after the surgery as compared to baseline. The Oswestry Disability Index (ODI) derives from the Oswestry Low Back Pain Questionnaire, it is used to measure disability for low back pain. The index is scored from 0 to 100; 0 meaning 'no disability' and 100 meaning 'maximum disability'.

The number of analyzed at 12 months only included subjects who had available data.

Document number of participants that returned to work 12 months after surgery.

The analyzed subjects at 12 months only included the subjects who had available data.

The primary objective of the study is to access the short term recovery (from surgery to discharge) since the minimally invasive lumbar fusion techniques are expected to be associated with immediate short-term benefits. Patients undergoing minimally invasive procedures are reported to recover earlier from surgery particularly with a shorter time to first ambulation and shorter discharge as compared to the standard open procedures.

Surgery recovery day is defined as the day when patients fulfils following criteria : patient no longer needs intravenous infusion of analgesic drugs, there are no surgery related complications (AEs) impending discharge of patient, patient no longer needs nursing care. The objective of the surgery recovery day assessment is to collect the day when the patient could be discharged based on his actual clinical condition because the effective day of discharge may be prolonged by factors other than the patient's clinical recovery such as social factors.