Which are the most frequent full-endoscopic lumbar approaches ?
There are thRee main approaches in endoscopic lumbar spine surgery.
Trans-foraminal
Inter-laminar
Extra-foraminal
Please note that de name of the approach actually describes the trajectory of het endoscope and NOT the anatomic localization of the pathology.
Eg. an foraminal disc herniation is most often approached with the extra-foramina approach.
Trans-foraminal approach
This approach is mostly used for acces to the spinal canal to decompress a spinal nerve by resection of a disc herniation. Since the working channel is fixed in the lower neuro-foramen there is is limited mobility for the endoscope. High or low migrated disc fragments can sometimes not be reached. Only pathology in the spinal canal wich is not lower than the upper border of the inferior pedicle and the middle of the superior pediclel can be correctly removed.
Simplified visualization of a full-endoscopic trans-foraminal approach on a plastic spine model with an endoscope. Its purpose is to help to understand, in a more abstract way, how this approach is performed
Indication of this approach: pathology in the spinal canal not lower than the upper border of the inferior pedicle and the middle of the superior pedicle: on this spine model between the pink lines.
Clinical picture of the extra lateral trans-foraminal approach the skin incision is at the lateral side of the body
Inter-laminar approach
Simplified visualization of a full-endoscopic interlaminar approach on a plastic spine model with an endoscope. Its purpose is to help to understand, in a more abstract way, how this approach is performed.
A 8 mm incision in made just lateral to the spinous process. The primairy aim of the scope is the interlaminar window of the affected level. After incision en passing the flavor the secondary aim is the shoulder area of the transveressing nerve in the laterale recess.
Clinical picture of the inter laminar approach the skin incision is at the midline dorsal side of the back
Extra-foraminal approach:
For treatment of FORAMINAL PATHOLOGY (herniation, cysts or bony occlusion) a far lateral approach is made at the side of the body. You aim is to ve able to enter the foramen in a horizontal angle.
The enty point in the skin is closer to the midline for EXTRA FORAMINA PATHOLOGY. The primary goal is not to hit the displaced exiting nerve.
Extra-foraminal disc herniations can be addressed bij a postero-lateral approach. The starting point distance from the midline is measured on CT or MRI scan.
Aiming target is the pedicle where it merges with the ascending facet. When the pedicul is identified dissection is proceeded anteriorly. A smal potion of bone (of the cranial part of the inferior vertebra) is followed until disc space is found. From the disc the location of the disc herniation can easily be found. If dissection cranial of the exiting nerve is necessary the dome of the facet joint hast tot be followed when dissection.
Extra-froaminal and foraminal disc herniations can be approached by a extreme lateral extra-foraminal approach , a trans foraminal of postero-laterateral approach. The choice depends on the anatomic localization of the herniation.