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Robotics in Vascular Surgery: Current Status and Potentials

Clinical Review

Robotics in Vascular Surgery: Current Status and Potentials

Author Information:
Jeroen Diks, MD and Willem Wisselink, MD, PhD

While endoscopic surgery has rapidly made headway among various specialties, vascular surgeons worldwide still seem uncomfortable surrendering to this minimally invasive technique.

Despite a small number of impressive series of laparoscopy-assisted and totally laparoscopic aortic treatments, the technical challenge of this approach seems to prevent vascular surgeons from frequently practicing this technique. This explanation might be due to the fact that the laparoscopic approach of the (abdominal) aorta and the laparoscopic creation of an aortic anastomosis is a serious technical challenge that demands a great deal of practice and experience before it can be applied in a clinical setting.<sup>1–5</sup>

Recently-introduced robotic surgical systems might assist in resolving the majority of these technical difficulties. With a superior 3D-vision, increased degrees of freedom (DOFs), better ergonomics and the possibility to up- and down-scale the instrument movements, hand-eye coordination is facilitated and the learning curve can be significantly reduced when compared to conventional endoscopic techniques.<sup>6</sup>

In this paper, the current status of robot-assisted laparoscopic treatment in vascular surgery is shared. We report on an experimental laboratory study, using a da Vinci<sup>®</sup> surgical system (Intuitive Surgical, Sunnyvale, California) to compare robot-assisted versus conventional laparoscopic aortic reconstruction with an interposition graft. Subsequently, we report on our clinical experience with both the da Vinci surgical system and the Zeus<sup>®</sup> surgical system (Computer Motion, Goleta, California) in aortobifemoral bypass grafting as a treatment for aortoiliac occlusive disease.

When Computer Motion merged with Intuitive Surgical (mid-2003), production of the Zeus system was discontinued, leaving the da Vinci system the only one available on the market. Technical support for the Zeus systems purchased before the merger is being continued by Intuitive Surgical. In-depth descriptions of the two robotic surgical systems may be found elsewhere.<sup>7</sup> The Zeus system consists of three robotic arms, positioned on the operation table, while the da Vinci robotic arms are positioned on a mobile cart. Both systems use a stereoscopic camera system and have small “wrists” at the end of the instruments, providing additional DOFs for the instrument movements. These are believed to contribute to better hand-eye coordination and increased dexterity, thus aiding inexperienced endoscopic surgeons and shortening the learning curve for technically challenging tasks, such as creation of intracorporeal vascular anastomosis.
In spite of the high interest in this topic, as demonstrated at vascular meetings, a Medline search revealed only modest information on the use of robot-assisted laparoscopic surgery (RALS) in the field of vascular surgery. Clinical vascular experience with robotics has been limited to an incidental case report<sup>8,9</sup> and a limited number of small series,<sup>10–12</sup> whereas other fields such as urologic, cardiac, pediatric and gastrointestinal surgery<sup>13</sup> have fashioned a large quantity of literature beyond the extent of this article.

<b>Experimental Work</b>
In order to determine the safety, efficiency and feasibility of RALS for reconstruction of the abdominal aorta, we conducted an experimental study on a porcine model in our laboratory. RALS was compared to the usual laparoscopic approach.<sup>14</sup>

Ten interposition grafts were sutured in an end-to-end fashion, with aid of robotic techniques using the da Vinci robotic system, into the abdominal aorta through a retroperitoneal approach. The outcomes were compared to ten interposition grafts constructed with conventional laparoscopic techniques.

Operating time, blood loss and complications were documented and the effectiveness of the anastomoses were assessed by measurement of the postoperative blood flow and the passage, circumference and number of stitches on eamination of the aorta at autopsy after sacrificing the animals.

Total operation-time (skin-to-skin) was 164 minutes (range: 116–225 minutes) in the robot-assisted group versus 205 minutes in controls (range: 162–244 minutes). Proximal anastomosis time was 22 minutes (range: 15–37 minutes, robot) versus 40 (range: 31–75 minutes), distal anastomosis time was 22 (range: 14–40) versus 41 minutes (range: 28–46 minutes, controls). No intraoperative complications occurred in the robot-assisted group. In the control group, the vena cava was injured in one case and subsequently tamponated before continuing the procedure. At autopsy, all robot-assisted anastomoses were macroscopically adequate. In the control group, a large distance (> 3 mm) between two stitches was measured in 10 cases. This study demonstrated the security, efficiency and feasibility of RALS for the abdominal aorta. The operation could be performed faster, with fewer complications and lower blood-loss with RALS than through a regular laparoscopic approach.

<b>Clinical Experience</b>
After initial clinical experience with laparoscopy-assisted aortobifemoral bypass in which a hand-sewn aortic anastomosis by means of a small incision was conducted after laparoscopic retroperitoneal dissection of the infrarenal aorta, we progressed to total laparoscopic procedures in which the aortic anastomosis was fashioned with aid of a robotic system (Figure 1). Between February 2002 and April 2006, 20 patients (18 males, 2 females), median age 57 (range: 36–72), presented with disabling claudication due to extensive aortoiliac occlusive disease. Five patients were operated on with the Zeus system between February 2002 and February 2003, when our institution had a Zeus surgical system on loan. In January 2004, our hospital acquired a da Vinci surgical system, and between February 2004 and April 2006, an additional 15 patients were operated on with the system.

After extensive laboratory practice sessions with both the Zeus and the da Vinci robotic surgical systems, approval from our hospital’s Investigational Review Board and the patient’s informed consent were obtained, and all patients underwent robot-assisted, laparoscopic aortobifemoral bypass. All patients had undergone earlier attempts at endovascular revascularization which were either unsuccessful or insufficient.

<b>Surgical Technique</b>
Details of different surgical techniques have been described elsewhere.<sup>1–7</sup> After initially using the retroperitoneal approach and then the transabdominal approach with the “apron” technique, the transabdominal approach, with extreme patient rotation, proved to be the best approach. While under general anaesthesia, the patient is positioned supine with a Pelvic Tilt pillow (O.R. Comfort, LLC, Branchburg, New Jersey) under the left flank. The robotic system is covered in sterile drapes, to be inserted into the surgical field at a later stadium. The common femoral arteries are dissected free bilaterally via small groin incisions.

Subsequently, the operating table is maximally rotated and the pillow is inflated until a right lateral and rotated decubitus position is achieved with the abdomen rotated at 85–90°. The surgeon stands at the right side of the patient, facing the patient’s abdomen and the video monitor, which is placed at the patient’s left side. Six 12-mm trocars are inserted (Figure 2). Laparoscopic transabdominal dissection of the infrarenal aorta and bifurcation is performed with a 30° endoscope (STORZ Endoskop Produktions GmbH, Tuttlingen, Germany), while clipping of the lumbar arteries is performed with a Ligasure™ Vessel Sealing System (Valleylab, Boulder, Colorado). The inferior mesenteric artery is temporarily occluded. Two retroperitoneal tunnels are prepared from the groin incision towards the aorta by means of passing a blunt clamp, visualizing intra abdominal passage with the endoscope. Aortic clamps are placed in position, the proximal clamp is inserted through an incision in the abdominal wall, and then the distal clamp is inserted through an earlier-placed 12-4 mm trocar (Figure 2). Subsequently, the robotic system is introduced into the surgical field and the surgeon takes his/her place behind a separate console from which the robotic arms are controlled. The endoscope is replaced by a 30° 3D-endoscope of the surgical system.

Full heparinization is instituted, and the aorta is clamped just distally to the renal arteries and below the inferior mesenteric artery. An aortotomy is made with a pair of pots scissors (Endowrist™ Pots Sisscors, Intuitive Surgical). A bifurcated polytetrafluororethylene (PTFE) (WL Gore and Associates, Flagstaff, Arizona) prosthesis (diameter 16 x 8 mm or 14 x 7 mm, depending on the anatomy) is stained orange with rifampicine to prevent light reflections. An end-to-side anastomosis is made with a CV-4 PTFE (WL Gore and Associates) running suture by means of robotically-steered instruments consisting of two needle drivers (Endowrist Needle Drivers).

Following completion of the aortic anastomosis, the two graft limbs are tunnelled to the groins, where a conventional end-to-side anastomosis is performed to the common femoral artery.

<b>Results</b>
Median operative time was 360 minutes (range: 225–589 minutes), with a median anastomosis time of 37.5 minutes (range: 21–110 minutes), and a median aortic clamp time of 78.5 minutes (range: 25–205 minutes). The long clamp time in one patient was due to technical problems with the camera system. The set-up time for the robotic system was 17 (± 5) minutes. Median blood loss was 1050 milliliters (range: 100–5800mL). A normal diet was resumed on the second postoperative day (POD) and median hospital stay was 5 days (range: 3–57 days).

Operative complications occurred in four patients. In one case, bleeding from an earlier clipped lumbar artery resulted in a loss of visibility after making the robot-assisted aortic anastomosis, which coincided with severe declamping hypotension. An acute conversion to open surgery was performed by means of a 15-cm flank incision to control the bleeding. The robotic vascular anastomosis showed no leakage and was left alone. The patient, however, required prolonged postoperative respiratory support and developed transient renal failure and severe critical illness polyneuropathy. At follow-up after 6 months, he had made a near-complete recovery. The second conversion was caused by the tearing of the peritoneum, which resulted in continuous CO2 leakage and the bowel migrating into the retroperitoneal space, thereby obstructing the operative field and vision. A 15-cm flank incision was made for retraction and performance of a hand-sewn, end-to-side anastomosis. A third conversion to open surgery was necessary because the robotic surgical system failed at start-up. It later seemed the battery of the system had malfunctioned and needed to be replaced. The last conversion was required after completion of the aortic anastomosis, when the intestine migrated into the operative field before the unclamping of the aorta. There was a total loss of vision, and a decision to convert to open surgery was made because the surgeons were unable to review the anastomosis. A 15-cm flank incision was made for inspection after clamp removal. The anastomosis showed no leakage and was left alone.

One patient died on postoperative day 3 due to a massive myocardial infarction. At autopsy, pinpoint coronary stenoses were found that had been missed during pre-operative cardiac workup. The aortic anastomosis was found to be intact.

<b>Discussion</b>
Ever since the introduction of minimally invasive vascular surgery, techniques such as laparoscopy-assisted and hand-assisted laparoscopic procedures for aortobifemoral bypass have been developed. In these procedures, the aortic dissection is performed laparoscopically, in contrast to the handmade aortic anastomosis, which requires an abdominal incision of 7–15 cm. This is in contrast to total laparoscopic procedures, where an incision is avoided altogether. Laparoscopic creation of an aortic anastomosis, however, is indisputably challenging and requires a great deal of practice and experience before being applied into everyday clinical practice. On the other hand, the addition of robotic assistance to these procedures offers an ergonomic and natural interface between the surgeon’s hands and the instrument tips, as well as increased freedom of motion due to wrist action of the robotic instruments. It therefore seems to facilitate creation of the aortic anastomosis, making a total laparoscopic procedure for aortobifemoral bypass more easily accessible to the “common” vascular surgeon.

<b>Conclusions and Future Prospects</b>
With the introduction of endovascular techniques, an effective alternative treatment for occlusive aortoiliac disease has emerged. However, aneurysmal disease still remains a challenging procedure for endovascular therapists. Mostly due to disappointing long-term results in endovascular abdominal aortic aneurysm repair, aneruysmal disease treatment leaves openings for conventional surgical repair. If improvement of endoscopic and robotic technologies can further decrease the invasiveness and complication rates of surgical aortic replacement, this technique might return as a first-choice approach in the treatment of aortoiliac disease, especially in younger patients.

Furthermore, in combination with endovascular therapy, robot-assisted endoscopic suturing may prove practical in graft fixation and aortic branch management, both at thoracic and abdominal levels.<sup>14</sup> Celiac, mesenteric and renal revascularization procedures, if unsuitable for endovascular repair, will be greatly facilitated by robotic techniques.

In conclusion, robotic assistance to laparoscopic procedures has been shown to offer a significant surplus value in the surgical treatment of infrarenal aortoiliac occlusive disease. It seems legitimate to assume the same benefits can be accounted for in the treatment for aortoiliac aneurysmal disease, but further investigation is needed. With future technical improvement and the availability of both robotic and endoscopic techniques, it seems worthwhile to recommend that vascular surgeons obtain or at least maintain a basic level of laparoscopic skills in anticipation of this technology.

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