Friday, December 6, 2013
Over the past 15 years, minimally invasive general surgery has rapidly expanded to include laparoscopic and robotic techniques for cholecystectomy, colectomy, gastric weight loss, and other procedures. Cholecystectomy, for example, a procedure that previously required a 10-inch incision in the abdominal wall, today routinely requires only several small incisions, all measuring less than one inch.
In contrast, for liver and pancreas surgery, minimally invasive techniques were adopted more slowly owing to the complexity of these procedures. Surgeons from the Hepatopancreatobiliary Service at Memorial Sloan Kettering have performed more than 4,000 liver resections for malignancy over the past 19 years for a wide array of malignant liver disease, both primary and secondary.
As a worldwide leader in the field, we have developed and continue to perfect minimally invasive techniques, both laparoscopic and robotic, as well as intraoperative navigation, to expand the treatment options for patients with hepatic malignancy.
Laparoscopic Liver Surgery Technique
Initially, laparoscopic liver resections were performed for small malignant tumors or symptomatic benign tumors. As experience grew and technology advanced, we expanded the use of laparoscopy into all aspects of liver surgery. Currently, we perform more than 40 minimally invasive liver resections annually (Figure 1).
One of the early concerns was whether cancer outcomes, such as margins and local recurrence rates, would be the same with laparoscopic procedures as they are for open procedures.
From the analysis of our case-control study of individually matched pairs operated from 1998 through 2008, we found that laparoscopy was associated with significantly reduced blood loss, frequency of transfusion, frequency of Pringle maneuver, postoperative morbidity, recovery time, length of hospital stay, and incidence of incisional hernia.
Additionally, for patients with malignant tumors, we found that there was no compromise of the surgical margins or local recurrence in either group, and that the overall pattern of recurrence was similar. In short, laparoscopic resections were shown to have similar operative and cancer outcomes in well-selected patients. (1)Back to top
Robotic Liver Surgery Technique
More recently, we have developed robotic liver surgery techniques using the da Vinci® Surgical System (Figure 2). Robotic instrumentation can provide the surgeon with greater flexibility in some minimally invasive settings, due to the wristed motion that mimics the movements of the human hand. This instrumentation functions in combination with a high-definition 3-D camera. We have increased the volume of robotic liver surgeries from none in 2009 to 15 cases per year in 2012. In addition, we are performing over 15 robotic cholecystectomies annually. Memorial Sloan Kettering’s institutional commitment to robotic surgery has aided us in this growth, and we now have five of the latest generation da Vinci® Si robots.Back to top
Liver Resection with Ablation
As the indications for surgical treatment of liver metastases have broadened, use of multimodal therapies has become more common. Today, approximately 20 percent of our liver resections are combined with ablation, a technique that uses heat energy from radiofrequency or microwave generators to destroy or ablate a tumor. Ablation plays a key role in hepatic parenchymal preservation because it enables treatment of tumors in areas that are not amenable to resection, and because it may be combined with resection of another area of the liver. (2)
In addition, ablations allow for the possibility of repeated treatments for recurrences with reduced morbidity. (3) For treatment of small hepatocellular carcinomas, evidence from retrospective studies has been accumulating in support of ablation instead of resection. (4)
In a retrospective study of our prospectively maintained database, we analyzed the recurrence patterns of colorectal cancer liver metastases treated with ablation via laparotomy between 1996 and 2010 and found that intraoperative ablation appears to be a highly effective treatment for colorectal cancer liver metastases of size equal to or smaller than 1 centimeter. (5)
Laparoscopic ablations are associated with a lower local recurrence rate when compared with percutaneous ablations. (4) Also, this technique allows for staging of the complete abdomen and the remainder of the liver via laparoscopic ultrasound. In addition, any bleeding caused by the procedure is controlled under direct vision and the ablation zone is monitored in real time.Back to top
Toward further advances, we have been evaluating an FDA-cleared image-guidance system, ExplorerTM, which allows for a 3-D model to guide minimally invasive liver surgery, including ablations. This image-guidance system is potentially very valuable for patients who have steatosis (often associated with a long course of chemotherapy), as it can be difficult to visualize small (<1 cm) tumors deep within the liver using only ultrasound in the operating room.
This system creates a 3-D model from preoperative CT scans (Figure 3), and the model is updated in real time to guide the surgical instruments during the resection or ablation. Results of our protocol that directly compared, for the purpose of validation, navigational data from the laparoscopic image-guidance system with that from the open image-guidance system showed that similar 3-D models were created. Continuing to improve intraoperative guidance will enhance surgical technique in both laparoscopic and open liver surgeries. (6)
The future for minimally invasive liver surgery is exciting. It has been shown that both laparoscopic and robotic procedures for general surgery have steep learning curves. (7) For liver surgery, the curve is even more extreme. With an experience of more than 300 hepatic resections per year, the surgeons on the Hepatopancreatobiliary Service at Memorial Sloan Kettering are well suited to take advantage of both laparoscopic and robotic techniques to continue to improve outcomes from liver surgery.