Transforaminal procedures with posterolateral access have been performed in the lumbar spine for more than 20 years now, mostly for intradiscal and intra and extraforaminal procedures. In our Department of Spine Surgery and Pain Therapy we have therefore been developing a lateral transforaminal and an interlaminar approach for full-endoscopic access to the spinal canal since 1998. These approaches broaden the range of indications and permit the use in selected indications of a visually controlled procedure that is as effective as conventional surgery while benefiting from all the advantages of truly minimally invasive surgery.

The fact that the lighting and imaging system with its 25° angle of vision is
situated right in the working area makes it possible to minimize traumatization
not only of the access pathway, but also of structures of the spinal canal.
Continuous irrigation provides excellent visual conditions. Mobility is achieved
by handling of the new endoscope using the joystick technique. Neural structures
are protected by use of the beveled operating sheath as a nerve hook. When
used in conjunction with the newly developed instruments, this is a genuinely
minimally invasive technique.

Percutaneous operations aimed at achieving intradiscal decompression of lumbar intervertebral discs were first described in the early 1970s. Optical systems designed for inspecting the intervertebral space after open operation were introduced in the early 1980s. Later, a full-endoscopic technique using a transforaminal approach was developed. In anatomic terms, this means that the intervertebral disc is reached via a posterolateral approach through the intervertebral foramen between the exiting and traversing nerve roots without need for resection of bony or ligamentous structures.

The skin entry point for operative access is determined in centimeters from the midline. Most such operations are performed for the purpose of intradiscal or extradiscal foraminal therapy. Reduction of intradiscal volume and pressure can reduce discrelated compression. Removal of intra and extraforaminal disc material is technically possible. Sequestered material lying within the spinal canal can generally be resected in retrograde fashion intradiscally via the annular defect. This is done using an "in-out" technique.