Percutaneous disc surgery at Balgrist since 1979--from discotomy to interbody fusion.

In 1979 percutaneous intervertebral surgery was introduced as an alternative to conventional open disc surgery. In 1982, discoscopy was developed for intraoperative monitoring of the selective removal of disc tissue at the site of herniation. The indication remains restricted to subligamentous contained herniations. In a series of 240 patients with a mean follow up of 53 months, 88% reached an at least satisfactory overall outcome. Newly developed endoscopic instrumentation demonstrate promising results for their use in the spinal canal as well as in the extradiscal spinal area. Since 1988, by means of new, specially adapted instrumentation, endoscopically controlled interbody fusion was introduced with temporary pedicular external fixation. In a series of 35 cases with monosegmental percutaneous fusion, at a mean follow-up of 25 months, the fusion rate--including initial pitfalls-- reached 29/35 (83%). The technique does not require blood transfusions, no remaining internal fixation is left. This minimally invasive approach facilitates functional rehabilitation. Some of the techniques presented in this article concerning percutaneous external fixation and percutaneous interbody fusion must be considered as experimental according to American FDA standards.