=====Foraminoscopy=====
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
((Mayer HM, Brock M: Percutaneous endoscopic lumbar discectomy (PELD). Neurosurg Rev 16:115–120, 1993))

Foraminoscopy was described by Mathews in 1996
((Mathews HH: Transforaminal endoscopic microdiscectomy. Neurosurg Clin N Am 7:59–63, 1996))
and Ditsworth in 1998.
((Ditsworth DA: Endoscopic transforaminal lumbar discectomy and reconfiguration: a posterolateral approach into the spinal canal. Surg Neurol 49:588–598, 1998)).

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.
((Kambin P, Zhou L: History and current status of percutaneous arthroscopic disc surgery. Spine (Phila Pa 1976) 21:24 Suppl57S–61S, 1996)).

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.
((Schubert M, Hoogland T: Endoscopic transforaminal nucleotomy with foraminoplasty for lumbar disk herniation. Oper Orthop Traumatol 17:641–661, 2005)).

Multichannel endoscopes with larger working channels were introduced by Tsou et al. in 1997
((Tsou PM, Yeung CA, Yeung AT: Posterolateral transforaminal selective endoscopic discectomy and thermal annuloplasty for chronic lumbar discogenic pain: a minimal access visualized intradiscal surgical procedure. Spine J 4:564–573, 2004))
and Ruetten et al. in 2007
((Ruetten S, Komp M, Merk H, Godolias G: Use of newly developed instruments and endoscopes: full-endoscopic resection of lumbar disc herniations via the interlaminar and lateral transforaminal approach. J Neurosurg Spine 6:521–530, 2007))

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

Yeung and Tsou in 2002
((Yeung AT, Tsou PM: Posterolateral endoscopic excision for lumbar disc herniation: Surgical technique, outcome, and complications in 307 consecutive cases. Spine (Phila Pa 1976) 27:722–731, 2002))
Ruetten el al. in 2007
((Ruetten S, Komp M, Merk H, Godolias G: Use of newly developed instruments and endoscopes: full-endoscopic resection of lumbar disc herniations via the interlaminar and lateral transforaminal approach. J Neurosurg Spine 6:521–530, 2007))
Ruetten et al. in 2008
((Ruetten S, Komp M, Merk H, Godolias G: Full-endoscopic interlaminar and transforaminal lumbar discectomy versus conventional microsurgical technique: a prospective, randomized, controlled study. Spine (Phila Pa 1976) 33:931–939, 2008))
and Jasper et al. in 2013
((Jasper GP, Francisco GM, Telfeian AE: Clinical success of transforaminal endoscopic discectomy with foraminotomy: a retrospective evaluation. Clin Neurol Neurosurg 115:1961–1965, 2013)).

see [[Percutaneous endoscopic lumbar foraminotomy]]