**4. The evolving role of MISS**

The advent of MISS techniques, initially for the treatment of degenerative conditions followed by applications in trauma, has led to the adoption of these techniques for oncological disease of the spine as well. MISS offers the opportunity to treat mechanical instability and epidural spinal compression in patients who otherwise may not tolerate a more extensive surgical approach due to heavy systemic disease burden [4, 10]. When considering the need for radiation and systemic chemotherapy, one postoperative barrier to adjuvant treatment is proper healing of the surgical incision. Smaller incisions involved with minimally invasive approaches may offer expedited time to chemotherapy and radiation therapy [4].

Many benefits of MISS can be attributed to minimizing tissue damage. Less tissue damage may also allow for quicker pain relief, decreased intake of opioids during the postoperative period, which may translate to early mobilization, functional recovery, and improvement in quality of life [4, 11]. Smaller incisions are also associated with less perioperative blood loss and transfusion requirements [12, 13].

Other benefits of MISS include preservation of the posterior elements, including the multifidus, which is one of the largest contributors of the posterior tension band and overall stabilization of the spine [14]. Given that many patients with spinal metastases frequently have compromised integrity of the spine, preservation of the tension band may prevent postoperative instability, kyphosis, and forms of instrumentation failure including screw pullout [14].

Disadvantages of MISS techniques include difficulty recognizing microsurgical anatomy given distortion by pathology in smaller spaces, as well as highly vascularized pathology that may lead to bleeding that is difficult to control. Both of these difficulties may require conversion to open approach [15]. Furthermore, the intricacy involved with MISS may lead to longer operative times [15]. Despite these risks, the ability for MISS techniques to offer preservation of function, symptomatic and palliative treatment for metastatic cancer with lower perioperative morbidity remains of great interest.
