Transforaminal Endoscopic Discectomy

Abstract

Minimally invasive surgery has conquered all fields of surgery. In particular, orthopedic surgery has contributedmuch to the development of instruments and techniques necessary for minimizing surgical approaches. However, the advances in minimally invasive joint surgery have yet not been seen in spinal surgery. There are various diagnoses of spinal disorders that would profit from minimally invasive surgery. The most common pathology addressed in spinal surgery is degenerative disc disease. The area of conventional disc surgery has already peaked. Due to patients’ postoperative complaints, generalized under the term “postlaminectomy syndrome,” the indications for conventional macroscopic disc surgery have been questioned in recent years. Parallel to this increase and decrease of conventional disc surgery, the idea of the minimally invasive approach has grown. The use of the microscope enabled conventional surgeons to minimize their skin incision combined with more accurate surgery in the spinal canal. However, in standard or microdiscectomy, open surgery is carried out and scarring occurs. The role of the scar as a source of postoperative pain is not yet explained. But avoiding the translaminar approach with bone removal, postoperative scarring due to hematoma, and all the possible complications is the goal of less invasive approaches. The posterolateral approach was addressed soon as a possible alternative to conventional surgery. The anatomy of the spine coming from a posterolateral aspect allows very differentiated access to nearly all relevant structures that need to be dealt with in disc surgery. Of all the different possible posterolateral approaches, one is called the transforaminal approach. The name already includes how the access way proceeds. The usual posterolateral approach is directed to the center of the disc. The transforaminal approach has been developed to address the more posterior parts of the disc including to some extent the anterior part of the spinal canal. This is wheremost of the disc pathologies are located. Moreover lateral portions of the disc, difficult to deal with in standard and microdiscectomy, can easily be reached. Therefore, the transforaminal approach seems ideal for about 80% of all disc lesions. Instruments have been developed with a diameter so small that foramina of normal height can easily host the nerve root, the fiberglass optic, and the instruments. This technique allows access to the epidural space from the lumbar disc as far cephalad as the middle of the vertebral body or approximately 2–3 mm caudally. The foraminal approach is routinely accessible from T10 to L4-5. L5-S1 can be accessed with special techniques that include foraminoplasty of the lateral facet.