27 Robotic Anterior Lumbar Interbody Fusion

10.1055/b-0039-172738

27 Robotic Anterior Lumbar Interbody Fusion

Patricia Zadnik Sullivan, Tristan Blase Fried, and William C. Welch

Abstract:

Robotic anterior lumbar interbody fusion (ALIF) is an innovative technique combining the advantages of laparoscopic technology and robotic surgical systems. Anterior approaches to lumbar spinal fusion are indicated for patients with lumbar instability and radiographic evidence of decreased lumbar lordosis or loss of interbody disk height. Historically, a large abdominal incision is made to allow an access surgeon to approach the anterior lumbar spine, then a neurosurgeon or an orthopaedic surgeon removes a disk and places an interbody cage. The use of a combined laparoscopic and robotic surgical system allows the surgeon to maintain manual dexterity and a wide view of the surgical field despite smaller incisions. One limitation of this technique is its reliance on multiple surgical teams, and poorly described federal and local regulations for its use. This chapter will review the technical aspects of robotic-assisted ALIF and discuss the advantages and limitations of this technique.

27.1 Introduction

Robotic surgical systems provide surgeons with increased dexterity and improve the operative view while eliminating the need for a surgical assistant to manipulate the endoscope. The surgeon is seated at a console in the operating room, controlling the wristed instruments at the end of the robotic arms. One of the most popular robotic systems, the da Vinci Surgical Robot, was developed by Intuitive Surgical and has been described in porcine, human cadaver, and human patient models of robotic anterior lumbar interbody fusion (R-ALIF). ¹ ^, ² ^, ³ ^, ⁴ This robotic system utilizes arms that can be fitted with scalpels, graspers, and electrocautery; however, no bone-cutting or rongeur instruments have been developed for use. The da Vinci robot has been approved by the United States Food and Drug Administration (FDA) for general surgery procedures involving laparoscopy, as well as urological, gynecological, and a subset of cardiac procedures. ⁵ To date, the FDA has not approved the use of robotic surgical systems in ALIF procedures.

Early technical notes for the use of the R-ALIF described proof of principle on living pigs and human cadavers. ⁴ ^, ⁶ These studies describe the use of the robot for the entirety of the procedure; and allow the neurosurgeon, orthopaedic surgeon, or neurosurgical researcher to complete all stages of the procedure. Unfortunately, most neurosurgeons and orthopaedic surgeons are not familiar with the laparoscope or credentialed to utilize the robotic surgical system from the start to the end of the case; thus, nonhuman and human cadaver models are the only technical descriptions of purely robotic techniques. Federal, vendor-specific, and hospital regulations restrict the use of the surgical robots for placement of instrumentation in human patients, and further large-scale studies will be needed before the widespread adoption of this technique. Furthermore, as orthopaedic and neurosurgical subspecialties continue to modify resident education, it is unclear if endoscopic and robot-assisted surgery will be incorporated into surgical training.

27.2 Technical Description

27.2.1 Animal Model

The proof of principle robot-assisted ALIF is described in a pig model. ³ ^, ⁴ ^, ⁶ Both the transperitoneal and retroperitoneal approaches are described in the pig model; however, the retroperitoneal approach will be described for illustration. The pig is placed in a right lateral decubitus position and a flank incision is made for a blunt tip balloon trocar for insufflation. Multiple incisions are made including a camera port, two robotic arm insertion ports, and assist port located above the camera. The robotic surgical system is docked and the surgeon takes a seat at the robotic console, directing the robotic arms using the device. The psoas muscle is identified and retracted to visualize the lateral aspect of the lumbar interbody disk space. The annulus is incised and disk material removed. An additional incision is made for the cage insertion port. An endoscope and expandable cage instruments are used to prepare the end plate. Finally, an expandable cage is inserted. A radiograph of the porcine lumbar spine is taken to confirm successful interbody placement. Technical difficulties complicated this approach, with the robot repeatedly freezing, requiring repositioning of the robotic arms and increasing the overall operative time to 6 hours. ⁶

27.2.2 Patient Case Reports

In the technical description of robotic-assisted laparoscopic ALIF in human patients, ¹ ^, ² ^, ⁴ the patient is positioned supine on a radiolucent table and prepped and draped in the usual fashion. A modified lithotomy position is used to provide internal retraction of pelvic viscera. Preoperative fluoroscopy provides localization for the level of interest. An access surgeon, specifically a urological or general surgeon with experience in the surgical robot, introduces the needle into the umbilicus for insufflation. A camera port is then introduced via the umbilicus. A 30-degree endoscope is used to enter the abdomen to visualize safe entry of an assistant port, as well as two or three additional instrument ports. The robot may then be docked to the camera port and instruments introduced to the abdominal cavity for transperitoneal dissection of the lumbar disk space of interest (Fig. 27‑1). Red rubber catheters may be used for intermittent, atraumatic retraction of the great vessels depending on the level of interest. The presacral plexus is identified and retracted, and the sacral artery and vein may be ligated or clipped.

**Fig. 27.1** Intraoperative photograph surgical robot docked to patient. The patient is supine in the lithotomy position. (Reproduced with permission from Lee et al. ¹ )

When the anterior disk space is fully exposed, fluoroscopy is used to confirm the correct level. Due to federal regulations, the robot may not be used for placement of spinal instrumentation; therefore, technical approaches for the robotic ALIF proceed using standard laparoscopy techniques. Specifically, a 2-cm incision is made approximately 5 cm superior to the pubic symphysis and a gel port is introduced to maintain pneumoperitoneum and allow passage of spinal instrumentation. This incision should reflect the angle necessary to approach the disk space of interest, and take into consideration the patient’s specific anatomy as well as the size of the implantable cage. The disk annulus is then incised, and the disk material and the end plates prepared for cage placement. A spacer is placed to confirm proper restoration of disk height and lordosis, and the final cage is packed with bone morphogenetic protein or other osteoinductive material, and placement is confirmed via intraoperative fluoroscopy.

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