Mini-invasive fenestrationMini-invasive fenestrationof the lumbar spine of the lumbar spine through a transspinous through a transspinous approachapproach

Pr Olivier GILLEPr Olivier GILLESpinal UnitSpinal UnitUniversity Hospital University Hospital Bordeaux FranceBordeaux France

Central stenosisCentral stenosis

The laminaThe lamina– Its proximal partIts proximal part

lateral recess stenosislateral recess stenosis

foraminal stenosis foraminal stenosis

Lumbar fenestration Lumbar fenestration described by Pr Senegas 1976described by Pr Senegas 1976

Alterations of erector spinae muscles following a posterior lumbar surgery

Assessment of erector Assessment of erector spinae musclesspinae muscles

Measurement of muscular strength with force Measurement of muscular strength with force measuring devices measuring devices

Measurement of the electromyographic Measurement of the electromyographic signalsignal

Measurement of the cross-sectional area Measurement of the cross-sectional area (CSA) of the muscles(CSA) of the muscles– Ultrasound studiesUltrasound studies– CT scansCT scans– MRIMRI

Measurement of signal density (CT scans) or Measurement of signal density (CT scans) or signal intensity (MRI)signal intensity (MRI)

Assessment of muscles using Assessment of muscles using MRIMRI

Measurement of muscle area on axial Measurement of muscle area on axial slidesslides

– Barker Spine. 2004Barker Spine. 2004– Parkkola Spine. 1993 Parkkola Spine. 1993 – Dangaria. Spine. 1998Dangaria. Spine. 1998

muscle signal intensitymuscle signal intensity– Visual assessment Visual assessment

– Salminen. J Spinal Disord. 1993; Parkkola R, Spine. Salminen. J Spinal Disord. 1993; Parkkola R, Spine. 19931993

– Region of interest (ROI) in the muscleRegion of interest (ROI) in the muscle– Gejo Spine 1999Gejo Spine 1999 – Kim Spine 2005Kim Spine 2005

Measurement of the muscle Measurement of the muscle contractile component cross-contractile component cross-section area (CCSA)section area (CCSA)

Area measurement by surrounding the Area measurement by surrounding the musclemuscle

signal intensity determination of the signal intensity determination of the contractile tissuecontractile tissue– Using 4 ROI in plain muscular zone Using 4 ROI in plain muscular zone

In collaboration with the biomechanics Laboratory of ENSAM, Paris

Measurement of the muscle Measurement of the muscle contractile component cross-contractile component cross-section area (CCSA)section area (CCSA)

CCSA

CCSA NCCSA

NCCSA

Pre operative MRI

Post operative MRI

Alterations of erector spinae Alterations of erector spinae muscles following a posterior muscles following a posterior lumbar surgerylumbar surgery

Following a posterior Following a posterior lumbar surgerylumbar surgery

the contractile component of the the contractile component of the erector spinae muscles decreases erector spinae muscles decreases of 25%of 25%

O.Gille, JM Vital. Erector spinae muscle changes on MRI following lumbar surgery through a posterior approach. Spine, 2008

LUMBAR SPINOUS PROCESS-SPLITING LAMINECTOMY

WATANABE , 2006

CHIMNEY SUBLAMINAR

DECOMPRESSION

LIN , 2006

CHO : « Marmot technique » , J. Neurosurgery Spine 2007

No high rate of improvementLong time surgeryTechnically difficultLong learning curve“Blind” surgeryHigh risk of nerve root or dural tear

Step 1: Length spinous process measurement on preop MRI

•Step 2: Spinous process osteotomy using a straight osteotom (3 mm security)

•Step 3: Osteotomy at the base of the spinous process performing with a curved osteotom.

•Step 5: The decompressive procedure can be continue as usual

•Step 4: Osteotomy of the distal part of the lamina using a curved osteotom

L4

L5

OpticalOptical magnification magnification Head lightHead light Operative time < 30 mnOperative time < 30 mn No blood lossNo blood loss

15 15 patientspatients Lumbar canal stenosisLumbar canal stenosis

– One levelOne level preop and 3 months postop preop and 3 months postop

MRIMRI– Quality of decompressionQuality of decompression– Assessment of muscle changesAssessment of muscle changes

Measurement of the cross-sectional Measurement of the cross-sectional area of the spinal canal (T2 area of the spinal canal (T2 sequence)sequence)

Preop Postop

Preop Postop

ResultsResults

Preop spinal canal area : 0.8 cm²Preop spinal canal area : 0.8 cm²

Postop spinal canal area : 2.1 cm²Postop spinal canal area : 2.1 cm²

Measurement of the Measurement of the MULTIFIDUS AND LONGISSIMUS MULTIFIDUS AND LONGISSIMUS contractile component cross-contractile component cross-section area (CCSA) section area (CCSA) (T1 (T1 sequence)sequence)

Preop Postop

MeasurementMeasurement of the of the MULTIFIDUS AND LONGISSIMUS MULTIFIDUS AND LONGISSIMUS contractile component cross-contractile component cross-section area (CCSA) section area (CCSA) (T1 (T1 sequence)sequence)

Preop Postop

ResultsResults

Following a transspinous approachFollowing a transspinous approach::– the contractile component of the the contractile component of the

erector spinae muscles decrease erector spinae muscles decrease less than 5% (Mean 4.8)less than 5% (Mean 4.8)

ConclusionConclusion

Advantages of fenestration through Advantages of fenestration through transspinous approach:transspinous approach:

Technically simpleTechnically simple Minimal soft tissues injuryMinimal soft tissues injury Short time surgery (< 30 mn)Short time surgery (< 30 mn) Excellent working space and visualizationExcellent working space and visualization Less bleedingLess bleeding Less postoperative pain ?Less postoperative pain ?

LimitsLimits:: Difficulties for repairing a dural tearDifficulties for repairing a dural tear