Even with good results, conventional disc operations may result in consecutive damage due to traumatisation. Endoscopic techniques have become the standard in many areas because of the advantages they offer in surgical technique and in rehabilitation. The transforaminal operation is the most common full-endoscopic procedure in surgery of the lumbar spine. It is frequently necessary to reach the spinal canal directly in order to achieve sufficient resection of lumbar disc herniations. Even in using a lateral approach, the authors recognise the clear limitations of the transforaminal procedure. The objective of this prospective study was to examine the technical possibility of a full-endoscopic interlaminar access. The focus was on questions of sufficient decompression, as well as advantages and disadvantages of the minimally invasive procedure. 331 patients were followed for 2 years. The results show that 82 % reported no longer having leg pain, and 13 % had only occasional pain. The decompression results are equivalent to those of conventional procedures. Traumatisation of both the access pathway and the spinal canal structures was reduced. Epidural scarring was minimised. The recurrence rate was 2.4 %. No serious surgical complications were observed. The authors view the technique described, which offers the advantage of a truly minimally invasive procedure, as a sufficient and safe alternative to conventional procedures, when the appropriate indication criteria are heeded. There are technical problems because of the small instruments. In conjunction with the transforaminal procedure, this is an expansion of the spectrum for full-endoscopic surgery of lumbar disc herniations.