Minimally invasive spinal surgical methods and instruments

A minimally invasive method for arthrodesis of a spinal motion segment of a patient including a cephalad vertebra and a caudal vertebra, comprising the steps of:

• making a transverse incision in the skin of the patient of about 2.5 cm at a generally posterolateral location about 10 cm from the midline at the level of a spinous process of the cephalad vertebra and centered over the border of the reflection of the thoracolumbar fascia;
• exposing the posterior leaf of the thoracolumbar fascia beneath the skin;
• making a second incision of about 2.5 cm through the thoracolumbar fascia in the direction of the fibers of the thoracolumbar fascia, the second incision centered beneath the transverse incision;
• creating a channel through the transverse incision and the second incision to the intertransverse interval of the cephalad vertebra and the caudal vertebra, including
• dissecting the lateral border of the iliocostalis lumborum from the anterior leaf of the thoracolumbar fascia;
• dissecting the iliocostalis lumborum and longissimus thoracis muscles from the fascia medially about 0.5 cm dorsal to the junction of the transverse process and the lateral cortex of the cephalad articular facet;
• and
• medially dissecting the intertransverse process membrane to the hiatus of the posterior rami of the segmental nerve and vessels;
• inserting a probe through the channel to the intertransverse interval;
• inserting a cannula into the channel and over the probe to the intertransverse interval;
• removing the probe from the cannula;
• inserting a burr into the cannula;
• decorticating the transverse process of the caudal vertebra with the burr;
• decorticating the transverse process of the cephalad vertebra with the burr;
• and
• delivering graft material to the intertransverse interval after the decorticating steps.