Minimally invasive spine surgery in chronic low back pain patients.

Low back pain (LBP) is a common disorder with a lifetime prevalence of 85%. The pathophysiology of LBP can be various depending on the underlying problem. Only in about 10% of the patients specific underlying disease processes can be identified. Patients with scoliosis, spondylolisthesis, herniated discs, adjacent disc disease, disc degeneration, failed back surgery syndrome or pseudoartrosis all have symptoms of LBP in different ways. Chronic low back pain patients are advised to stay active, however, there is no strong evidence that exercise therapy is significantly different than other nonsurgical therapies. Not every patient with symptoms of LBP is an appropriate candidate for surgery. Even with thorough systematic reviews, no proof can be found for the benefit of surgery in patients with low back pain, without serious neurologic deficit. And subjects like psychologic and socio-demographic factors also seem to be influencing a patients perception of back pain, expectations of treatment, and outcomes of treatment. Open lumbar fusion procedures are typically lengthy procedures and require a long exposure, which may result in ischemic necrosis of the paraspinal musculature, atrophy, and prolonged back pain. Minimally invasive spine surgery needed to take care of a decrease in muscle injuries due to retraction and avoidance of disruption of the osseotendineous complex of the paraspinal muscles, especially the multifidus attachment to the spinous process and superior articular process. Therefore, effort has been made to develop percutaneous fusion, as well as fixation methods, which avoid the negative effects of open surgery. Several minimally invasive fusion strategies have been described, like anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF) and two lateral approaches (XLIF and DLIF), all with pro's and con's compared to open surgery and each other. The effect of MIS of all type is that patients have less blood loss, faster postoperative ambulation, lower use of opioids, and shorter in hospital stay, which is nearly always significantly better than an open procedure. And most of the studies show a significant improvement of VAS leg-and back pain, Oswestry Disability Index and a high fusion rate, but most of the times not significantly different than the open counterpart. When it comes to cost-effectiveness there is a trend in favor of MIS, but to when we want to differentiate MIS from open surgery, comorbidities and complications significantly affect general and disease-specific outcome measures. In our opinion, the actual better outcome of minimal invasive surgery comes down to obtain a good cost-effectiveness study, provided that minimally invasive surgery has an equal or better clinical and radiologic outcome, given that socio-economic, demographic and psychological influencers are equal for both types of surgery. There are no studies done on the subject MIS and low back pain solely. Deriving answers from the difference in VAS back pain in MIS studies reveal a 100% improvement of back pain after surgery. But that does not imply that this procedure, which is still in its childhood, will be the solution to all low back pain patients.