Is there additional information from laparoscopic ultrasound in tumor staging?

Value of Intraoperative Sonography in Pancreatic Surgery

The utility of intraoperative sonography for pancreatic disease has been well described for detection and evaluation of neoplastic and inflammatory pancreatic disease. Intraoperative sonography can help substantially reduce surgical time as well as decrease potential injury to tissues and major structures. Imaging with sonography literally at the point of care--the surgeon's scalpel--can precisely define the location of pancreatic lesions and their direct relationship with surrounding structures in real time during surgery. This article highlights our experience with intraoperative sonography at multiple institutional sites for both open and laparoscopic surgical procedures. We use intraoperative sonography for a wide range of pancreatic disease to provide accurate localization and staging of disease, provide guidance for enucleation of nonpalpable, nonvisible tumors, and in planning the most direct and least invasive surgical approach, avoiding injury to the pancreatic duct or other vital structures.

A systematic review of the accuracy and indications for diagnostic laparoscopy prior to curative-intent resection of gastric cancer

BACKGROUND

Despite improved preoperative imaging techniques, patients with incurable or unresectable gastric cancer are still subjected to non-therapeutic laparotomy. Diagnostic laparoscopy (DL) has been advocated by some to be essential in decision-making in gastric cancer. We aimed to identify and synthesize findings on the value of DL for patients with gastric cancer, in this era of improved preoperative imaging.

METHODS

Electronic literature searches were conducted using Medline, EMBASE, and the Cochrane Central Register of Controlled Trials from January 1, 1998 to December 31, 2009. We calculated the change in management and avoidance of laparotomy based on the addition of DL and laparoscopic ultrasound (LUS). The accuracy, agreement (kappa), sensitivity, and specificity of DL in assessing tumor extent, nodal involvement, and the presence of metastases with respect to the gold standard (pathology) were also calculated.

RESULTS

Twenty-one articles were included. DL showed moderate to substantial agreement with final pathology for T stage, but only fair agreement for N stage. For M staging, DL had an overall accuracy, sensitivity, and specificity ranging from 85-98.9%, 64.3-94%, and 80-100%, respectively. The use of DL altered treatment in 8.5-59.6% of cases, avoiding laparotomy in 8.5-43.8% of cases. LUS provided additional benefit in 5.8-7.2% of cases.

CONCLUSIONS

Despite evolving preoperative imaging techniques, diagnostic laparoscopy continues to be of substantial value in staging patients with gastric cancer and in avoiding unnecessary laparotomy. The current data support DL for all patients with advanced gastric cancer.

Intraoperative ultrasonography: a useful tool in retrolaparoscopic nephron-sparing surgery

OBJECTIVE

To evaluate the value of intraoperative laparoscopic ultrasonography (ILUS) in retrolaparoscopic nephron-sparing surgery.

METHODS

A total of 81 cases were studied during a 5-year period: 38 patients with a benign renal tumor who underwent enucleation of the tumor and 43 patients with a suspected malignant renal tumor who underwent wedge resection of the tumor. ILUS was used to evaluate renal perfusion, locate the tumor, precisely delineate the tumor border, characterize the tumor, and look for any suspected satellite renal masses.

RESULTS

All procedures were successful without conversion to open surgery. The mean operating time was 106 min for enucleation (range 70- 150 min) and 114 min for wedge resection (range 80- 235 min). The mean size of benign tumors was 4.02 cm and that of malignant tumors was 3.13 cm, and all margins were negative. An additional renal artery branch was detected in 11 patients. In 2 cases the operative procedure was changed based on the ILUS findings. No satellite lesion was found in any of the patients with malignant tumors.

CONCLUSIONS

ILUS provides significant benefit in retrolaparoscopic nephron-sparing surgery. In a number of situations, especially endogenic lesions, it is an essential surgical tool.

Laparoscopic ultrasound: a survey of its current and future use, requirements, and integration with navigation technology

BACKGROUND

Laparoscopic ultrasound (LUS) increases surgical safety by allowing the surgeon to see beyond the organ surface, by visualizing vascular structures and by improving surgical precision of tumor resection. A questionnaire-based survey was used to investigate the current use and future expectations of LUS technology.

METHODS

A questionnaire consisting of 26 questions was distributed manually at four different conferences (60% at the European Association for Endoscopic Surgery (EAES) conference, Stockholm 2008). The answers were summarized with descriptive statistics and nonparametric tests at a significance level of 0.05.

RESULTS

The questionnaire was answered by 177 surgeons from 40 different countries (85% from Europe). Of these surgeons, 43% use ultrasound during laparoscopic procedures. Generally, more LUS users are found at university hospitals than at general community hospitals. Surgeons use LUS primarily in procedures related to the liver (67% of the surgeons who use LUS), but LUS also is used in other procedures related to the pancreas, biliary tract, and colon. In a 5-year perspective, 82% of surgeons believe in an increased use of LUS, and 79% of surgeons also think that the use of LUS combined with navigation technology will increase and that the most important requirements for such a system are good image quality, easy interpretation, and a high degree of precision.

CONCLUSIONS

Although the surgeons believe LUS has advantages, only 43% of the respondents reported using it. The surveyed surgeons were largely positive toward an increased use of LUS in a 5-year perspective and believe that LUS combined with navigation technology will contribute to improving the surgical precision of tumor resection.

Vascular invasion in pancreatic cancer: Imaging modalities, preoperative diagnosis and surgical management

Pancreatic cancer is associated with a poor prognosis, and surgical resection remains the only chance for curative therapy. In the absence of metastatic disease, which would preclude resection, assessment of vascular invasion is an important parameter for determining resectability of pancreatic cancer. A frequent error is to misdiagnose an involved major vessel. Obviously, surgical exploration with pathological examination remains the “gold standard” in terms of evaluation of resectability, especially from the point of view of vascular involvement. However, current imaging modalities have improved and allow detection of vascular invasion with more accuracy. A venous resection in pancreatic cancer is a feasible technique and relatively reliable. Nevertheless, a survival benefit is not achieved by curative resection in patients with pancreatic cancer and vascular invasion. Although the discovery of an arterial invasion during the operation might require an aggressive management, discovery before the operation should be considered as a contraindication. Detection of vascular invasion remains one of the most important challenges in pancreatic surgery. The aim of this article is to provide a complete review of the different imaging modalities in the detection of vascular invasion in pancreatic cancer.

Magneto-optical tracking of flexible laparoscopic ultrasound: model-based online detection and correction of magnetic tracking errors

Electromagnetic tracking is currently one of the most promising means of localizing flexible endoscopic instruments such as flexible laparoscopic ultrasound transducers. However, electromagnetic tracking is also susceptible to interference from ferromagnetic material, which distorts the magnetic field and leads to tracking errors. This paper presents new methods for real-time online detection and reduction of dynamic electromagnetic tracking errors when localizing a flexible laparoscopic ultrasound transducer. We use a hybrid tracking setup to combine optical tracking of the transducer shaft and electromagnetic tracking of the flexible transducer tip. A novel approach of modeling the poses of the transducer tip in relation to the transducer shaft allows us to reliably detect and significantly reduce electromagnetic tracking errors. For detecting errors of more than 5 mm, we achieved a sensitivity and specificity of 91% and 93%, respectively. Initial 3-D rms error of 6.91 mm were reduced to 3.15 mm.

Assessment of pancreatic malignancy with laparoscopy and intraoperative ultrasound

BACKGROUND

Staging laparoscopy for pancreatic malignancy is controversial. This study aimed to assess the efficacy of laparoscopy with intraoperative ultrasound in the management of patients with pancreatic carcinoma.

METHODS

The study involved patients undergoing laparoscopy and intraoperative ultrasound over a period of 42 months. The entry criteria specified radiologic (computed tomography) diagnosis of pancreatic carcinoma and no evidence of metastases.

RESULTS

The study enrolled 100 patients (52 men and 48 women) ages 21 to 83 years (mean, 63 years). On the basis of imaging, 75 patients had lesions judged to be operable, and 25 patients had a pancreatic head lesion larger than 4 cm radiologically, considered to be unresectable, but with no evidence of metastatic disease. At laparoscopy, three patients had a normal examination, with no evidence of a pancreatic mass, and an additional seven patients had other pathology including one lymphoma, one ampullary tumor, two cases of chronic pancreatitis, and three sarcomas. Of the patients with radiologically inoperable disease, 16% had previously undetected metastases, but 24% were judged to be suitable for curative resection. Half of these patients underwent successful resection. Of the patients with radiologically operable disease, undetected liver or peritoneal metastases were found in 20% of the body or tail lesions and in 26% of the pancreatic head lesions. Of the pancreatic head tumors, 12% were found to be larger than 4 cm and therefore unsuitable for curative resection. Consequently, only 53% were confirmed to be suitable for resection. Of the patients explored with a view to curative resection, 42% actually underwent resection, with clearance of resection margins achieved in 77.8%.

CONCLUSION

Of the patients thought to have a resectable tumor on the basis of good quality preoperative imaging, 44% had their management approach altered after laparoscopy and avoided an open procedure. Laparoscopy should therefore be used in the preoperative staging of pancreatic tumors.

DaVinci canvas: a telerobotic surgical system with integrated, robot-assisted, laparoscopic ultrasound capability

We present daVinci Canvas: a telerobotic surgical system with integrated robot-assisted laparoscopic ultrasound capability. DaVinci Canvas consists of the integration of a rigid laparoscopic ultrasound probe with the daVinci robot, video tracking of ultrasound probe motions, endoscope and ultrasound calibration and registration, autonomous robot motions, and the display of registered 2D and 3D ultrasound images. Although we used laparoscopic liver cancer surgery as a focusing application, our broader aim was the development of a versatile system that would be useful for many procedures.

Evidence-based diagnosis and staging of pancreatic cancer

Only 20% of patients who present with pancreatic cancer will be amenable to potentially curative resection. Therefore, it is necessary to reliably identify patients who might benefit from major surgical intervention by employing the appropriate staging methods. In this review, the pros and cons of each imaging technique are discussed and an algorithm for single and combined use of the different imaging modalities is proposed. To date, contrast-enhanced multi-detector row helical CT (MDR-CT) together with endoscopic ultrasound (EUS) remain the first staging methods of choice. MDR-CT has a high sensitivity for identifying vascular invasion and EUS is able to detect lesions as small as 2-3 mm. ERCP is performed mainly in patients with biliary obstruction with the option for therapeutic intervention during the same session. MRI with MR-angiography, MRCP, PET/CT and staging laparoscopy are additional modalities which might give further information in cases of equivocal findings by MDR-CT and EUS. The role of tumour markers such as CA 19-9 and CEA is reserved for monitoring and diagnosing post-surgery recurrence. Cytological or histological confirmation should usually be performed in patients that are not eligible for surgery prior to the commencement of palliative radio- or chemotherapy. In the routine clinical setting, MDR-CT and EUS play the predominant roles by providing the most cost-effective and accurate means for diagnosing and staging most cases of pancreatic cancer.

An evidence-based approach to the diagnosis and staging of pancreatic cancer

Technology has revolutionized the diagnosis and staging of pancreatic malignancy. Previously, staging of disease was accomplished by exploratory laparotomy. Now, however, tumor size, lymph node and vascular involvement and the presence of metastases can be reliably assessed prior to operation using a widely available series of diagnostic tests, facilitating a preoperative assessment of tumor resectability. Appropriate use of these tests often spares patients with unresectable disease the need for operative intervention. As part of our staging algorithm we routinely employ a combination of clinical suspicion, a high-resolution helical CT scan and a serum CA 19-9 level. Endoscopic ultrasonography is useful in the patient in whom CT findings are equivocal, or in whom a tissue diagnosis is desired. Laparoscopy is reserved for patients with suspected advanced disease despite imaging findings to the contrary. Using this strategy, pancreatic malignancy may be diagnosed as expeditiously and as cost-effectively as is possible given current technology.

Diagnostic laparoscopy: indications and benefits

BACKGROUND

The increased availability of treatment options for gastrointestinal cancer, necessitates precise preoperative staging. Laparoscopy can be useful for establishing the diagnosis and staging of cancer. However, there is an ongoing discussion as to whether staging laparoscopy provides additional results despite newly developed imaging tools.

METHODS

A systematic review of relevant literature was undertaken. The strength of evidence was classified according to the North of England Evidence Based Guidelines Development Project. Medline and manual searches were carried out to identify all published manuscripts of clinical trials that dealt with staging laparoscopy. Systematic quality review of those publications was used to verify staging accuracy, complications and trocar metastases.

RESULTS

Only one randomized trial was performed in gynaecological cancer. In cervical cancer, as a result of this study, staging laparoscopy remains unproven. In gastrointestinal cancer (oesophageal, gastric, pancreatic, liver and colorectal cancers) only prospective and retrospective observational studies are available with an evidence-based level of grade B. As a result of these trials, staging laparoscopy, in a well-defined group of patients with locally advanced cancer, is recommended.

CONCLUSION

The effects of surgical staging in gynaecological cancer must be kept in mind but cannot be transferred to gastrointestinal cancer in general. Further studies are required to answer those questions.