Perspectives Commentary on: Minimally Invasive Transforaminal Lumbar Interbody Fusion for Spondylolisthesis: Comparison Between Isthmic and Degenerative Spondylolisthesis by Kim et al. World Neurosurg 2015 http://dx.doi.org/10.1016/j.wneu.2015.06.003
Considerations When Contemplating Minimally Invasive Versus Open Transforaminal Lumbar Interbody Fusion Dean Chou
T
ransforaminal lumbar interbody fusion (TLIF) has tremendous utility in the treatment of spondylolisthesis. Not only does it augment rates of arthrodesis, but it also allows for foraminal height restoration, which can be a main problem in spondylolistheses because of the up-down stenosis. Moreover, the loosening of the vertebral segments, which occurs with removal of the disc and unilateral facetectomy, can also allow for reduction of the Meyerding grade and slip angle. Thus, there are advantages of the TLIF over a simple posterior lateral fusion. Minimally invasive surgery (MIS) of the spine has been evolving, and techniques are generally becoming better. It has been shown that MIS spine surgery has a lower rate of infection, lower rate of blood loss, and shorter hospital stay. However, there is a learning curve associated with MIS spine surgery. In addition, there is a potential of increased operative time, especially while adapting the new technique, and there is also a potential of increased costs given the implants and equipment. There is also potentially an increased exposure to radiation for the surgeon and patient in MIS surgeon or prolonged operative time with intraoperative navigation. Minimally invasive treatment of spondylolisthesis via TLIF has been shown to be a safe and effective alternative to open TLIF. Whether open or MIS, the basic tenets are the same: decompression of the neural elements, stabilization of the spine, increase in foraminal height, and possibly reduction in either Meyerding grade or slip angle. The main discrepancy between the 2 approaches, however, is that the MIS TLIF is limited when
Key words Degenerative spondylolisthesis - Gill body - Isthmic spondylolisthesis - Minimally invasive surgery - MIS - TLIF -
Abbreviations and Acronyms MIS: Minimally invasive surgery TLIF: Transforaminal lumbar interbody fusion
WORLD NEUROSURGERY - [-]: ---, MONTH 2015
performing a posterior lateral fusion, and it relies heavily on the interbody fusion to take place. Within a degenerative spondylolisthesis, the facets and pars interarticularis are intact, thus allowing for some stabilization and possibly facet arthrodesis on the side contralateral to the TLIF. However, in isthmic spondylolistheses, the bilateral pars defects preclude a contralateral facet fusion and don’t provide any contralateral stability. Thus, there is a valid theoretical concern that an MIS TLIF in patients with isthmic spondylolisthesis may have a greater rate of failure than an open TLIF because there is no posterior lateral fusion bed, only an interbody fusion. The authors present 41 cases of patients who underwent open and MIS TLIF. The patients all had 1-year follow-up with computed tomography scans, and assessment of fusion and outcomes were performed. The authors found no difference in MIS TLIF in patients with either an isthmic spondylolisthesis or a degenerative spondylolisthesis. The strength of this article is that it shows with good, validated outcome measures and radiographic support that isthmic spondylolistheses treated with an MIS TLIF do not have inferior outcomes compared with degenerative spondylolistheses treated in an open fashion. The authors also further to show that in patients with isthmic spondylolistheses, their foraminal height restoration was slightly greater than that of degenerative slips. This is not surprising,
Department of Neurosurgery, University of California San Francisco, San Francisco, California, USA To whom correspondence should be addressed: Dean Chou, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015). http://dx.doi.org/10.1016/j.wneu.2015.06.053
www.WORLDNEUROSURGERY.org
1
PERSPECTIVES
given the nature of the respective pathologies. In isthmic cases, the lack of a pars connection allows for an easier loosening and separation of the vertebral bodies from one another. In degenerative cases, the generally older, more arthritic and hypertrophied contralateral facets can impede height restoration. The authors have shown that even with an MIS approach, significant foraminal height can be achieved in both groups. Because spondylolisthesis with stenosis of the lumbar spine is one of the most common pathologies seen by spine surgeons, the application of MIS techniques for treatment is a logical one. The less disruptive nature of the approach may yield clinical benefits to the patient during their postoperative recovery period. There are surgeons who may routinely treat isthmic spondylolistheses via the traditional, open Gill laminectomy with fusion, even though they are more than capable of performing an MIS TLIF. This article may give such surgeons the reassurance that treating isthmic spondylolisthesis via an MIS approach is an alternative. When interpreting the data and conclusions of this study, the reader should also keep in mind that most of the degenerative
2
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pathologies were at L4 5, and most of the isthmic pathologies were at L5 S1. Because of this, there is an inherent selection bias when comparing these 2 groups, and the reader should keep this in mind. In conclusion, the authors have asked a very specific question, and using good outcome measures with computed tomography imaging at one-year follow-up, they have given support to their conclusions. This article will also be useful to the reader who questions the utility of MIS TLIF in isthmic spondylolisthesis, and it will contribute to the growing body of literature of MIS spine surgery.
Citation: World Neurosurg. (2015). http://dx.doi.org/10.1016/j.wneu.2015.06.053 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.06.053
Considerations When Contemplating Minimally Invasive Versus Open Transforaminal Lumbar Interbody Fusion Dean Chou
T
ransforaminal lumbar interbody fusion (TLIF) has tremendous utility in the treatment of spondylolisthesis. Not only does it augment rates of arthrodesis, but it also allows for foraminal height restoration, which can be a main problem in spondylolistheses because of the up-down stenosis. Moreover, the loosening of the vertebral segments, which occurs with removal of the disc and unilateral facetectomy, can also allow for reduction of the Meyerding grade and slip angle. Thus, there are advantages of the TLIF over a simple posterior lateral fusion. Minimally invasive surgery (MIS) of the spine has been evolving, and techniques are generally becoming better. It has been shown that MIS spine surgery has a lower rate of infection, lower rate of blood loss, and shorter hospital stay. However, there is a learning curve associated with MIS spine surgery. In addition, there is a potential of increased operative time, especially while adapting the new technique, and there is also a potential of increased costs given the implants and equipment. There is also potentially an increased exposure to radiation for the surgeon and patient in MIS surgeon or prolonged operative time with intraoperative navigation. Minimally invasive treatment of spondylolisthesis via TLIF has been shown to be a safe and effective alternative to open TLIF. Whether open or MIS, the basic tenets are the same: decompression of the neural elements, stabilization of the spine, increase in foraminal height, and possibly reduction in either Meyerding grade or slip angle. The main discrepancy between the 2 approaches, however, is that the MIS TLIF is limited when
Key words Degenerative spondylolisthesis - Gill body - Isthmic spondylolisthesis - Minimally invasive surgery - MIS - TLIF -
Abbreviations and Acronyms MIS: Minimally invasive surgery TLIF: Transforaminal lumbar interbody fusion
WORLD NEUROSURGERY - [-]: ---, MONTH 2015
performing a posterior lateral fusion, and it relies heavily on the interbody fusion to take place. Within a degenerative spondylolisthesis, the facets and pars interarticularis are intact, thus allowing for some stabilization and possibly facet arthrodesis on the side contralateral to the TLIF. However, in isthmic spondylolistheses, the bilateral pars defects preclude a contralateral facet fusion and don’t provide any contralateral stability. Thus, there is a valid theoretical concern that an MIS TLIF in patients with isthmic spondylolisthesis may have a greater rate of failure than an open TLIF because there is no posterior lateral fusion bed, only an interbody fusion. The authors present 41 cases of patients who underwent open and MIS TLIF. The patients all had 1-year follow-up with computed tomography scans, and assessment of fusion and outcomes were performed. The authors found no difference in MIS TLIF in patients with either an isthmic spondylolisthesis or a degenerative spondylolisthesis. The strength of this article is that it shows with good, validated outcome measures and radiographic support that isthmic spondylolistheses treated with an MIS TLIF do not have inferior outcomes compared with degenerative spondylolistheses treated in an open fashion. The authors also further to show that in patients with isthmic spondylolistheses, their foraminal height restoration was slightly greater than that of degenerative slips. This is not surprising,
Department of Neurosurgery, University of California San Francisco, San Francisco, California, USA To whom correspondence should be addressed: Dean Chou, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015). http://dx.doi.org/10.1016/j.wneu.2015.06.053
www.WORLDNEUROSURGERY.org
1
PERSPECTIVES
given the nature of the respective pathologies. In isthmic cases, the lack of a pars connection allows for an easier loosening and separation of the vertebral bodies from one another. In degenerative cases, the generally older, more arthritic and hypertrophied contralateral facets can impede height restoration. The authors have shown that even with an MIS approach, significant foraminal height can be achieved in both groups. Because spondylolisthesis with stenosis of the lumbar spine is one of the most common pathologies seen by spine surgeons, the application of MIS techniques for treatment is a logical one. The less disruptive nature of the approach may yield clinical benefits to the patient during their postoperative recovery period. There are surgeons who may routinely treat isthmic spondylolistheses via the traditional, open Gill laminectomy with fusion, even though they are more than capable of performing an MIS TLIF. This article may give such surgeons the reassurance that treating isthmic spondylolisthesis via an MIS approach is an alternative. When interpreting the data and conclusions of this study, the reader should also keep in mind that most of the degenerative
2
www.SCIENCEDIRECT.com
pathologies were at L4 5, and most of the isthmic pathologies were at L5 S1. Because of this, there is an inherent selection bias when comparing these 2 groups, and the reader should keep this in mind. In conclusion, the authors have asked a very specific question, and using good outcome measures with computed tomography imaging at one-year follow-up, they have given support to their conclusions. This article will also be useful to the reader who questions the utility of MIS TLIF in isthmic spondylolisthesis, and it will contribute to the growing body of literature of MIS spine surgery.
Citation: World Neurosurg. (2015). http://dx.doi.org/10.1016/j.wneu.2015.06.053 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2015.06.053
