In spine surgery postoperative pain can often be severe and difficult to treat.With the use of ultrasound, the performance of plane blocks and other techniques like root blocks, facet infiltration have become possible without the use of either unreliable " pop-techniques" or the use of x-ray.The erector spinae block was recently described as a safe and simple and safe technique for neuropathic pain and acute post surgical pain, with effect on the dorsal rami of the spinal nerves and with promising results. In this observational pilot study we want to test the influence of these to blocks on the postoperative pain and opioid consumption after spine fusion.