Michael Y. Wang, Andrew A. Sama and Juan S. Uribe (eds.)Lateral Access Minimally Invasive Spine Surgery10.1007/978-3-319-28320-3_3

3. Physiologic Benefits and Impacts of Minimally Invasive Spine Surgeries

Gisela Murray¹, Chun-Po Yen¹ and Juan S. Uribe²

(1)

Department of Neurological Surgery, University of South Florida, Tampa, FL 33606, USA

(2)

Department of Neurological Surgery, University of South Florida, Tampa, FL, USA

Juan S. Uribe

Email: juansuribe@gmail.com

3.1 Goals of Minimally Invasive Spine Surgery

Minimally invasive spine surgeries (MIS) are percutaneous or mini-open techniques utilized for spine decompression, fusion, instrumentation, or malalignment correction akin to their open counterparts with the benefits of reducing intraoperative blood loss, postoperative pain, infection, and complications. MIS surgery achieves these goals through minimizing dissection and crush injury to the paraspinal musculature and preserving posterior tension band. Introduction of tubular or expandable retractors and refinement of long and bayoneted instruments allow the spine surgeons not only able to perform the routine posterior decompressive procedures but also posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) [1, 2].

Another innovative breakthrough in the past decade is the minimally invasive lateral approach to the thoracic and lumbar spine utilizing the natural retroperitoneal or retropleural corridors [3, 4]. Originally used for degenerative spinal disorders, the lateral approach has expanded its indications to treat pathologies involving anterior and middle column of the spine such as trauma, neoplasm, and deformity. It replaces more morbid procedures, which often involve thoracotomy, laparotomy, or extensive posterolateral dissection [5–8]. Percutaneous pedicle screws and rods have been another powerful addition in the MIS spines surgeons’ armamentarium to stabilize and realign the spine [9].

3.2 Physiological Benefits

Many physiological benefits have been described for MIS in general. The most important are reduced blood loss, lower infection rates, and soft tissue envelope preservation.

3.2.1 Blood Loss

This has been the most consistent benefit of the MIS. In a prospective study of 61 patients undergoing single level PLIF through MIS or open approach, the authors found no clinical or radiological difference between the groups at 1 year minimum follow-up. However, there was significantly less blood loss and a lower transfusion rate in the MIS group [10]. In our experience, the average blood loss for a single level lateral interbody fusion (LIF) is approximately 50 ml per level [11]. This benefit is more obvious when the technique is used in complex spine pathologies. For example, in the case of thoracic corpectomies, the published average blood loss for MIS ranges from 543 to 1,857 mL in contrast to 2,100–3,136 ml when open surgeries were performed [6]. In the setting of scoliosis surgery, the difference is also conspicuous. In a recent publication for surgical correction of adult spine deformity, MIS averaged 669 ml of blood loss vs. an average of 2,322 ml with open techniques [12]. Less blood loss leads to lower allogeneic blood transfusion and lower risks of transfusion related complications and hospital costs.

3.2.2 Decreased Infection Rates

In general, the infection rate after spinal surgery is 2–4 %. Minimally invasive techniques have been associated with a lower infection rate than their open counterparts [13]. In a meta-analysis, the cumulative incidence of infection was 0.6 % for MIS TLIF vs. 4 % for open TLIF [14]. For MIS LIF, the reported infection rate approaches 0 %. In the largest recent series of 600 patients undergoing LIF, none developed an infection [15]. In our most recent published series of MIS correction of scoliosis, there was no case of infection from the lateral approach [16].

3.2.3 Reduced Soft Tissue Disruption

The harmful effects of paraspinal muscle dissection and retraction are well known. It has been shown that the serum markers indicating muscle injury are significantly lower in MIS fusion patients [17, 18]. Imaging studies also demonstrated less muscle edema with MIS fusion compared to open techniques [19]. These imaging findings correlated clinically with less pain and disability in patients undergoing MIS fusion. Additionally, less paraspinal muscle injury can be associated with preservation of the posterior ligamentous tension band. Whether the advantage of preserving posterior tension band can reduce the risks of proximal junctional kyphosis remains to be investigated.

Only gold members can continue reading. Log In or Register to continue