The History of and Controversy over Kambin's Triangle: A Historical Analysis of the Lumbar Transforaminal Corridor for Endoscopic and Surgical Approaches.

The transforaminal corridor in the lumbar spine allows access to the traversing and exiting nerve roots, the thecal sac, and the intervertebral disc space. Surgeons performing midline and minimally invasive approaches for lumbar interbody fusion access the disc space within the boundaries created by the exiting root of a segment and the traversing root after a complete facetectomy and removal of the pars interarticularis and lamina. Endoscopic surgeons and interventional pain management physicians approach the lumbar segment through a similar corridor, but with the bony anatomy intact. Although the boundaries of the corridor may seem the same, the angle of the trajectory and the bone work between the two differ. The overlap between these 2 distinct access corridors has led to an openhanded application of the term Kambin's triangle. Initially described for endoscopic approaches to the lumbar spine for microdiscectomy, this working triangle has been grafted into the transforaminal lumbar interbody fusion literature. Given the similarities between these corridors, it is understandable how the lines of this nomenclature have blurred. The result has been an interchangeable application of the term Kambin's triangle for a variety of procedures in the spine literature. The objective of the current work is to add clarity to the various lumbar transforaminal corridors. The term Kambin's triangle should be limited to percutaneous access to the disc space for endoscopic procedures in the intact spine and should not be applied to transforaminal lumbar interbody fusion after laminectomy and facetectomy. Instead, the term expanded transforaminal corridor should be applied.

Ischias. Von der Säftelehre zur Pathomorphologie.

Today, lumbar disc disease is a very common disease, which will be often seen in both the family practice as well as in the consultations of orthopedics, neurology, rheumatology or neurosurgery. Furthermore, lumbar disc surgery is one of the most common spinal surgical procedures worldwide. But, for many centuries, physician had no clear understanding of the anatomical condition and the pathomechanism of this disease. Therefore, no rational treatment was available. The Hippocratic physicians knew the signs and symptoms of lumbar disc disease, which they then called "sciatica". But, they subsumed different disorders, like hip diseases under this term. In the mid-18th century, it was the Italian physician Domenico Felice Antonio Cotugno (1736-1822), who first brought clarity in the concept of radicular syndromes; he recognized, that the so-called "sciatica" could be of neurogenic origin. In 1742, a contemporary of Cotugno, the German Josias Weitbrecht (1702-1747) has to be credited for the first precise description of the intervertebral disc. Nearby a hundred years later, the German Hubert von Luschka (1820-1875) described for the first time a herniated disc in a pathologic specimen. With the landmark report of the New England Journal of Medicine in 1934, the two American surgeons, William Jason Mixter (1880-1958) and Joseph Seaton Barr (1901-1963), finally cleared the pathomechanism of lumbar disc disease.

[Sciatica. From stretch rack to microdiscectomy]. / Ischias. Von der Streckbank zur Mikrodiskektomie.

In ancient times as well as in the Middle Ages treatment options for discogenic nerve compression syndrome were limited and usually not very specific because of low anatomical and pathophysiological knowledge. The stretch rack (scamnum Hippocratis) was particularly prominent but was widely used as a therapeutic device for very different spinal disorders. Since the beginning of the nineteenth century anatomical knowledge increased and the advances in the fields of asepsis, anesthesia and surgery resulted in an increase in surgical interventions on the spine. In 1908 the first successful lumbar discectomy was initiated and performed by the German neurologist Heinrich O. Oppenheim (1858-1919) and the surgeon Fedor Krause (1857-1937); however, neither recognized the true pathological condition of discogenic nerve compression syndrome. With the landmark report in the New England Journal of Medicine in 1934, the two American surgeons William Jason Mixter (1880-1958) and Joseph Seaton Barr (1901-1963) finally clarified the pathomechanism of lumbar disc herniation and furthermore, propagated discectomy as the standard therapy. Since then interventions on intervertebral discs rapidly increased and the treatment options for lumbar disc surgery quickly evolved. The surgical procedures changed over time and were continuously being refined. In the late 1960s the surgical microscope was introduced for spinal surgery by the work of the famous neurosurgeon Mahmut Gazi Yasargil and his colleague Wolfhard Caspar and so-called microdiscectomy was introduced. Besides open discectomy other interventional techniques were developed to overcome the side effects of surgical procedures. In 1964 the American orthopedic surgeon Lyman Smith (1912-1991) introduced chemonucleolysis, a minimally invasive technique consisting only of a cannula and the proteolytic enzyme chymopapain, which is injected into the disc compartment to dissolve the displaced disc material. In 1975 the Japanese orthopedic surgeon Sadahisa Hijikata described percutaneous discectomy for the first time, which was a further minimally invasive surgical technique. Further variants of minimally invasive surgical procedures, such as percutaneous laser discectomy in 1986 and percutaneous endoscopic microdiscectomy in 1997, were also introduced; however, open discectomy, especially microdiscectomy remains the therapeutic gold standard for lumbar disc herniation.