With the idea of a safe working triangle between the exiting and traversing roots in the foramen, endoscopic spine surgery started to leave the safety of the indigo carmine blue–stained nucleus and explore the lumbar intervertebral foramen.

In 1993 Mayer and Brock used an angled lens scope that allowed more dorsal visualization of anular pathology ¹⁾

Foraminoscopy was described by Mathews in 1996 ²⁾ and Ditsworth in 1998. ³⁾.

In 1996 Kambin and Zhou described lumbar nerve root decompression by anulectomy and decompression of lateral recess stenosis with the use of forceps and trephines. ⁴⁾.

In 2005 Schubert and Hoogland described their technique for transforaminal endoscopic removal of a sequestered disc fragment using reamers to expand the foraminal window by removing the ventral portion of the superior articular process. ⁵⁾.

Multichannel endoscopes with larger working channels were introduced by Tsou et al. in 1997 ⁶⁾ and Ruetten et al. in 2007 ⁷⁾

A number of reports of the clinical success of direct endoscopic decompression of foraminal pathology would follow:

Yeung and Tsou in 2002 ⁸⁾ Ruetten el al. in 2007 ⁹⁾ Ruetten et al. in 2008 ¹⁰⁾ and Jasper et al. in 2013 ¹¹⁾.

see Percutaneous endoscopic lumbar foraminotomy