The investiagtor abandoned the project.

For twenty years, as for other surgical disciplines, new minimally invasive techniques have been developed with the main goal the reduction of muscle trauma associated with the surrounding roads "classic" and reduce morbidity linked to this one.

More recently, minimally invasive methods dedicated to spinal surgery were established, for the treatment of herniated discs initially, then for narrow lumbar canals.

The canal release on minimally invasive fusion, using a tubular system for muscle retraction is a new technique that has proven effective: post operative pain reduction of hospital stay and blood loss.

The objective of the study is to investigate the quality of ductal release in these minimally invasive fusions.

Main objective of the study: Evaluation of the quality of the release of post scanners operative minimally invasive arthrodesis

Secondary Objectives: Assessment rates/types of early complications of technical Minimally invasive - early postoperative results (postoperative pain, analgesic consumption, length of hospital stay, blood loss) - in clinical outcomes in the short and medium term decompression after minimally invasive fusion.

I. Background / Rationale

For twenty years, as for other surgical disciplines, new minimally invasive techniques have been developed with the main goal the reduction of muscle trauma associated with the surrounding roads "classic" and reduce morbidity linked to this one.

More recently, minimally invasive methods dedicated to spinal surgery were established, for the treatment of herniated discs initially, then for narrow lumbar canals.

The canal release on minimally invasive fusion, using a tubular system for muscle retraction is a new technique that has proven effective: post operative pain reduction of hospital stay and blood loss.

The objective of the study is to investigate the quality of ductal release in these minimally invasive fusions.

II. objectives

at. primary objective

Evaluating the quality of discharge on postoperative scanners minimally invasive fusions.

b. secondary objectives

i. Evaluation of the rate and type of early complications in the minimally invasive technique

ii. Evaluation of early postoperative results (postoperative pain, analgesic consumption, length of hospital stay, blood loss)

iii. Evaluation of clinical outcomes in the short and medium term decompression after minimally invasive fusion.

III. Methodology and duration of the research

This is a retrospective single-center consecutive series multi-operator regarding the evaluation of surgical practice cited in goal.

Clinical data were collected prospectively by KEOPS database (SAMIO). All patients included in our study have spinal MRI scanners and pre-operative and post-operative scans.

N = (number of patients and over what period) / Time Study?

The series of patients will be classified into two groups:

• Foraminal stenosis
• Central stenosis

The evaluation of the primary objective criterion is comparing the height of the foramen measured on CT pre- and post-operative between the lower edge of the overlying pedicle and the top edge of the pedicle underlying the sagittal sections.

For central stenosis, Postoperative MRI will be performed and the volume of the dural sac will be compared to preoperative MRI on axial images.

Inclusion Criteria:

• Ductal compression on one floor
• Scanner spine preoperatively

Exclusion Criteria:

• Spondylolisthesis significant (greater than grade 2)
• Stenoses multi layered
• Major spinal deformities

Patients admitted to hospital with Paris Saint Joseph with canal compression on one floor, for whom a scan of the spine is performed preoperatively