Caudascopic experiences and a new patho-anatomic concept for treatment of sciatica

In order to investigate the potential of an exclusively endoscopic extradural approach as an alternative to open discectomy, epidural endoscopy was performed in 5 cadavers. This did not produce satisfactory images of the epidural space. Intradural endoscopy (caudascopy) was performed, to show whether additional anatomical factors might explain a radicular syndrome supplementary to or without a disc herniation. Caudascopy allowed excellent images of the cauda equina, nerve roots, and the entrance of the lumbar nerve root sheaths. A Fogerty balloon positioned in the intervertebral foramen was used to simulate disc herniation. The impact of this simulation on the intradural endoscopic image was observed to be minimal. A dural fold was identified at the entrance of the nerve root sheath. It is proposed as a factor contributing to the mechanical involvement of lumbosacral nerve roots. Pressure measurements in the intradural nerve root sheath support this preliminary finding. An endoscopical management of this potential patho-anatomy of the nerve root is suggested.