Comment to the article: "Tubular diskectomy vs conventional microdiskectomy for sciatica: a randomized controlled trial".

Arts MP et al. Tubular Discectomy vs. Conventional Microdiscectomy ... Minim Invas Neurosurg 2010; 53: 95–96 the underlying hypothesis for this study was fl awed. A meaningful trial would have compared surgical procedures where diff erences in surgical technique are likely to actually make a clinically relevant diff erence – for tubular surgery this would be a comparison between tubular lumbar fusion vs. open surgery, as has been shown by several case series and comparative studies [3 – 11] . For example, a recent study from Asia demonstrated signifi cantly reduced muscle injury in a group of patients undergoing MISS fusion vs. those undergoing open surgery [12] . The lack of benefi t from tubular discectomy over conventional surgery does not mean that tubular surgery would not have a signifi cant advantage when comparing potentially much more invasive procedures. The concerning fi nding in the present study was that patients undergoing tubular discectomy actually did worse than conventional surgery in regards to selfreported leg and back pain and recovery. The authors are not able to explain this surprising result. They state that the length of the incision was the same in both groups; also other parameters such as the amount of disc removed and blood loss were very similar between groups. The main stated diff erence was the fact that the tubular procedures were done using the operating microscope while surgical loops (providing less magnifi cation) were used primarily for the conventional discectomy. It appears unlikely to us that the use of the microscope with tubular discectomy should be associated with a worse outcome, as their study suggests. Assuming that patients are adequately randomized between groups some of the reasons for worse surgical outcome could be problems with surgeon experience / level of training and limited or inadequate surgical exposure / visualization of the pathology at the time of surgery. Both these concerns cannot be excluded in this manuscript and actually seem likely. The authors state that the “ participating neurosurgeons had broad experience in both techniques ” . In our experience this is unlikely since most surgeons decide at some point in their career to go with either one or the other surgical technique. As demonstrated in our publications a signifi cant learning curve is associated with tubular discectomy and it seems unlikely that surgeons would go back and forth between surgical techniques (1,2). The fact that tubular discectomies took Comment to the article: