Dr Brian Fiani is recognised as a world-renowned Ivy-League fellowship-trained Neurosurgeon at Weill Cornell Medicine/NewYork-Presbyterian Hospital with sub-specialty focus on minimally invasive spinal surgery.
Minimally invasive spinal surgery (MISS) is a technique for performing spine surgery that is associated with less collateral tissue damage, less morbidity and pain, and more rapid functional recovery with the same or better outcomes than traditional techniques. Recently, new advances in microsurgical instruments, navigation technology, and intraoperative robotic technology have made this approach more popular, but yet, it is unique to be properly trained in this area of expertise. My objective is to introduce the tenets of MISS and how to incorporate these less-invasive techniques into daily practice as a surgeon.
The fundamental principle of MISS is that you can obtain big results from small incisions. Less invasive surgeries are better for the patients and help them return to their daily activities more quickly. In the era of Covid-19, MISS became even more critical because it allowed patients to have their necessary surgeries and return home without hospitalization. Hospitals were challenged by understaffing and were overwhelmed with virally infected patients. If there is no intended hospitalisation then patients can have surgery at ambulatory surgery centers. Having surgery at ambulatory surgery centers without hospitalisation decreases the rate of infections, is less intimidating for patients, and less burdensome on the hospital systems. The benefit of MISS is that it decreases the invasiveness particularly with procedures that are of moderate complexity. Lesser complexity surgeries typically involve less invasiveness and more complex deformity surgeries typically require more invasive techniques. However between these two scenarios lies the major caseload for MISS techniques.
Microsurgical instruments and tubular retractor systems were first introduced in 1997 for lumbar discectomies. Refinement in the surgical instruments have made microsurgery less cumbersome making smaller operative corridors possible, such as small tubes (Figure 1). The muscle-splitting technique of sequential tubular dilation mitigated tissue injury and therefore postoperative pain. Both decompressions and instrumented fusions can be performed through tubular retractors in anterior, lateral, and posterior approaches. Microscopes increase the illumination and visualization of microinstruments through small operative corridors.
Figure 1: Tubular retractors allow spine surgeons like Dr. Fiani to work through small operative corridors. Typical width of tubes are 15 mm, 18mm, or 21mm and have varying depth options based on patient body morphology.
Intraoperative navigation is particularly useful when performing MISS techniques. Navigation utilises intraoperative low-dose CT imaging to allow the spinal surgeon visualization of anatomy with depth beyond what is visible to the eye. The workflow consists of setting up a reference array, obtaining the intraoperative scan, using that scan for operative planning from surgical incision to placement of instrumentation or decompression. Most typically, with experienced surgical technicians and representatives from the companies involved there is a rapid calibration process. Navigation is very time efficient. It is cost efficient by preventing the necessity of revision surgeries if surgeries have inaccuracies. It decreases radiation exposure from fluoroscopy. Navigation enables complex MISS procedures to proceed with accuracy and precision.
Robotic spine surgery is the most recent development in spinal navigation. Pre-operative and intra-operative images are obtained to facilitate automated registration. A robotic arm moves into appropriate positions navigating the surgeon along the patient’s anatomy. The benefit of robotic spine surgery is the accuracy and guidance of trajectory. Next generation robotic technology has smaller operating room footprints, improved image quality, and rapid workflow. Though initial cost is a disadvantage to this technique, radiation exposure is dramatically reduced. Additionally, if the technology reduces operative times then cost savings occurs. The selection of navigational technology with/without robotic applications is based on the spine surgeon’s preference and level of comfort with the technology. Future directions of robotic spine surgery are leading to virtual reality and augmented reality systems.
Surgeons should consider the wealth of scientific data supporting MISS techniques. Short-term and long-term results comparing MISS and open surgeries indicate that patients have faster recovery from MISS approaches. However, specialised training and experience are required to perform these techniques. Therefore, operating surgeons should utilize the technique with which he/she is most proficient in order to avoid complications and achieve the best patient outcomes.