The utility of parathyroid autofluorescence as an adjunct in thyroid and parathyroid surgery 2023.

Thyroid and parathyroid surgery requires careful dissection around the vascular pedicle of the parathyroid glands to avoid excessive manipulation of the tissues. If the blood supply to the parathyroid glands is disrupted, or the glands are inadvertently removed, temporary and/or permanent hypocalcemia can occur, requiring post-operative exogenous calcium and vitamin D analogues to maintain stable levels. This can have a significant impact on the quality of life of patients, particularly if it results in permanent hypocalcemia. For over a decade, parathyroid tissue has been noted to have unique intrinsic properties known as "fluorophores," which fluoresce when excited by an external light source. As a result, parathyroid autofluorescence has emerged as an intra-operative technique to help with identification of parathyroid glands and to supplement direct visualization during thyroidectomy and parathyroidectomy. Due to the growing body of literature surrounding Near Infrared Autofluorescence (NIRAF), we sought to review the value of using autofluorescence technology for parathyroid detection during thyroid and parathyroid surgery. A literature review of parathyroid autofluorescence was performed using PubMED. Based on the reviewed literature and expert surgeons' opinions who have used this technology, recommendations were made. We discuss the current available technologies (image vs. probe approach) as well as their limitations. We also capture the opinions and recommendations of international high-volume endocrine surgeons and whether this technology is of value as an intraoperative adjunct. The utility and value of this technology seems promising and needs to be further defined in different scenarios involving surgeon experience and different patient populations and conditions.

Allotransplantation of cryopreserved parathyroid tissue for severe hypocalcemia in a renal transplant recipient.

We report the successful allotransplantation of cryopreserved parathyroid tissue to reverse hypocalcemia in a kidney transplant recipient. A 36-year-old male received a second deceased donor kidney transplant, and 6 weeks later developed severe bilateral leg numbness and weakness, inability to walk, acute pain in the left knee and wrist tetany. His total calcium was 2.6 mg/dL and parathormone level 5 pg/mL (normal 10-60 pg/mL). He underwent allotransplantation of parathyroid tissue cryopreserved for 8 months into his left brachioradialis muscle. Immunosuppression included tacrolimus (target C(0) 10-12 ng/mL), mycophenolate mofetil and steroids. Within 2 weeks, the left knee pain, leg weakness and numbness resolved, and by 1 month he could walk normally. After a peak at month 2, his parathyroid hormone (PTH) level fell to <10 pg/mL; therefore at month 3 he received a second parathyroid transplant from the same donor. Eight months later (11 months after initial graft) he has a total calcium of 9.3 mg/dL, PTH level 15 pg/mL and is clinically asymptomatic. The amount of parathyroid tissue needed to render a patient normocalcemic is not known. In our case, the need for second transplant suggests that the amount of tissue transferred for an allograft may need to be substantially greater than for an autograft.

Histological, CT, and intraoperative ultrasound appearance of hepatic tumors previously treated by laparoscopic radiofrequency ablation.

PURPOSE: The purpose of this paper is to compare intraoperative biopsy results of previously ablated liver tumors with their preoperative computed tomography (CT) and intraoperative laparoscopic ultrasound (LUS) appearances in patients undergoing repeat radiofrequency ablation (RFA). METHODS: Seventy repeat RFA procedures were performed in 59 (13%) patients. Laparoscopically, suspected recurrent and stable appearing foci were biopsied using an 18 G biopsy gun. Preoperative CT and LUS appearances of the previously ablated lesions were compared with core biopsy results. RESULTS: There were 33 patients with colorectal cancer, 11 with hepatocellular cancer, 8 with neuroendocrine tumors, and 7 with other tumor types. Two hundred lesions were treated by RFA in these 70 repeat ablations. Suspected recurrent tumor foci were enhanced on CT and produced a more finely stippled echo pattern on LUS. Biopsy confirmed recurrent tumor in 72 of 84 such lesions. Previously ablated foci had a CT appearance of a hypodense, nonenhancing lesion without evidence of adjacent enhancing foci. Laparoscopic ultrasound appearance was of a hypoechoic lesion with a coarse internal pattern with the tracks of the ablation catheter probes often still visible. Biopsy found necrotic tissue in 21 of 22 such lesions appearing radiologically to be without recurrence. Biopsy of an ablated focus adjacent to an area of suspected recurrence showed necrotic tissue in 17 of 22 lesions and viable cancer in 5. CONCLUSION: CT and LUS appearance of previously ablated foci showed good correlation with core biopsies. CT scan is reliable in following RFA lesions, without the need for routine biopsy. LUS reliably distinguished recurrent from ablated lesions in patients undergoing repeat ablation.

Perioperative outcome after laparoscopic radiofrequency ablation of liver tumors: an analysis of 521 cases.

BACKGROUND: Radiofrequency thermal ablation (RFA) is gaining increased acceptance for the treatment of unresectable primary and metastatic liver tumors. Understanding the morbidity and laboratory changes after RFA is important for operative indications and perioperative management. METHODS: The authors prospectively analyzed the 30-day morbidity and mortality rates of patients undergoing laparoscopic RFA for liver tumors in a 10-year period. Laboratory studies included a complete blood count, electrolytes, liver function tests, prothrombin time/international normalized ratio (INR), and tumor markers obtained preoperatively, on postoperative days (PODs) 1 and 7, then at 3 months. RESULTS: A total of 521 RFA procedures were performed for 428 patients (286 men and 142 women) with a mean age of 61 years (range, 25-89 years). A total of 346 patients underwent a single operation, and 82 patients had two or more operations. The pathology was metastatic colon cancer for 244 patients (47%), hepatocellular cancer for 109 patients (21%), metastatic neuroendocrine cancer for 74 patients (14%), and other noncolorectal, nonneuroendocrine liver metastasis for 94 patients (18%). A total of 1,636 lesions (mean, 3.1 per patient; range, 1-16) were ablated. The mean tumor size was 2.7 +/- 1.6 cm (range, 0.3-11.5 cm). All cases were managed laparoscopically. The 30-day mortality rate was 0.4% (n = 2), and the morbidity rate was 3.8 % (n = 20). The average length of hospital stay was 1 day for RFA-only cases and 2.1 days when another surgical procedure was combined with RFA. Serum aspartate aminotransferase (AST) increased 14-fold, alanine aminotransferase (ALT) increased 10-fold, and bilirubin levels increased 2-fold on POD 1, with return to baseline in 3 months. Serum alkaline phosphatase and gamma-glutamyltransferase (GGT) levels showed a 25% increase on POD 7, with return to baseline in 3 months. There were no significant changes in platelet counts or prothrombin times postoperatively. CONCLUSIONS: This large series provides valuable insight into the perioperative period and allows the expected morbidity of the procedure to be understood. Despite significant patient comorbidities, this procedure was tolerated with low morbidity and mortality rates. Postoperative coagulopathy was not observed. A postoperative rise in liver function tests is expected, reflecting the liver injury response to RFA. This information can be used to expand the patient population that may benefit from laparoscopic RFA.

Laparoscopic radiofrequency thermal ablation for unusual hepatic tumors: operative indications and outcomes.

BACKGROUND: There is increasing experience with laparoscopic radiofrequency ablation for the treatment of patients with hepatic metastasis from colorectal and neuroendocrine cancer and those with hepatocellular cancer. Little is known about the outcomes for patients with other tumor types. METHODS: Between January 1996 and March 2005, 517 patients with 1,500 primary and metastatic liver tumors underwent laparoscopic radiofrequency ablation. Among these, 53 patients (10%) had cancers other than the colorectal, neuroendocrine, or hepatocellular types including sarcoma (n = 18), breast cancer (n = 10), esophagus cancer (n = 4), melanoma (n = 4), lung cancer (n = 3), ovarian cancer (n = 2), pancreas cancer (n = 2), unknown primary cancer (n = 2), cholangiocarcinoma (n = 2), rectal squamous cancer (n = 2), renal cancer (n = 2), papillary thyroid cancer (n = 1), and hemangioendothelioma (n = 1). Unlike the criteria for treatment of the more usual tumor types, these patients had a diagnosis of liver-exclusive disease, as diagnosed by preoperative imaging. They also had failed chemotherapy. RESULTS: The 53 patients underwent ablation of 192 lesions, with 8 patients undergoing repeat treatment. The hospital stay averaged 1 day, and there was no 30-day mortality. Complications included one postoperative hemorrhage, one liver abscess, and one wound infection. Tumors recurred locally for 17% of the lesions over a mean follow-up period of 24 months. The overall median survival was 33 months for the whole series, more than 51 months for breast cancer, and 25 months for sarcoma. CONCLUSION: Laparoscopic radiofrequency ablation can safely and effectively treat hepatic metastasis of these unusual tumor types. The authors believe that this heterogeneous group of patients, selected for their unusual presentation of liver-exclusive disease, may benefit from cytoreduction of their tumor by laparoscopic radiofrequency ablation when other treatment methods have failed.

Predictors of survival after laparoscopic radiofrequency thermal ablation of hepatocellular cancer: a prospective study.

BACKGROUND: Most patients with hepatocellular carcinoma (HCC) are not candidates for hepatic resection or liver transplantation. Radiofrequency ablation (RFA) provides local control for unresectable HCC with minimal morbidity. The aim of this prospective study is to determine factors predicting survival in patients with HCC undergoing RFA. METHODS: Sixty-six consecutive patients with HCC who were not candidates for a curative liver resection and were free of extrahepatic disease underwent laparoscopic RFA. The relationship between demographic, clinical, laboratory, and surgical parameters and survival was assessed using univariate Kaplan-Meier survival and multivariate Cox proportional hazards model. RESULTS: The median Kaplan-Meier survival for all patients was 25.3 months after RFA. Although alfa fetal protein (AFP), bilirubin, ascites, and Child class were statistically significant predictors of survival by univariate analysis, only the Child class and AFP were independent predictors by multivariate analysis. CONCLUSIONS: This study determines which patients do best after RFA and shows that RFA can provide significant survival for patients with unresectable HCC while also forming a bridge to liver transplantation. RFA has become the first line of treatment in the management of these patients.

Laparoscopic radiofrequency ablation of hepatic tumors: prospective clinical evaluation of ablation size comparing two treatment algorithms.

BACKGROUND: Radiofrequency ablation (RFA) is gaining increased acceptance for the local control of liver tumors. Essential for achieving local tumor control are reproducible volumes of ablation that encompass the tumor and a margin of normal liver parenchyma. The technical algorithm for performing ablations was arrived at in an animal model using normal liver. Limited amounts of data exist as to whether this translates to the human tumor model. METHODS: We analyzed 531 ablated lesions in 154 patients undergoing laparoscopic RFA using RITA Medical Systems Starburst XL catheter deployed to a final diameter of 2-5 cm. The first 54 patients (algorithm 1) were treated with a larger initial deployment to 3 cm and incremental advancement of the catheter to the final diameter with a 20-min ablation time for a 5-cm lesion. The subsequent 100 patients (algorithm 2) were treated with a smaller initial deployment of 2 cm, incremental advancement to the final diameter, and 14-min total ablation time for a 5-cm lesion. Lesion size was measured on 1 week postablation CT scans. Analysis was performed using the two-tailed t-test. RESULTS: Ablation zones tended to be larger with the second method. On 1 week postablation CT scans, mean +/- SEM lesion sizes created using the first and second algorithms were 3.7 +/- 0.1 cm vs 4.0 +/- 0.1 cm at 3 cm deployment ( p < 0.05); 4.3 +/- 0.1 cm vs 4.8 +/- 0.1 cm at 4 cm deployment ( p < 0.05), and 5.5 +/- 0.1 cm vs 5.6 +/- 0.2 cm at 5 cm deployment ( p > 0.05), respectively. The mean +/- SEM total ablation times for the first and second algorithms were 7.9 +/- 0.3 min vs 7.0 +/- 0.2 min at 3 cm deployment ( p < 0.05); 13.3 +/- 0.3 min vs 11.1 +/- 0.02 min at 4 cm deployment ( p < 0.05); and 27.8 +/- 1.2 min vs 21.4 +/- 1.2 min at 5 cm deployment ( p < 0.05), respectively. The small SEM values indicate little variation in lesion size. CONCLUSIONS: These results show that both algorithms create dependable and reproducible zones of ablation, essential for reliable tumor destruction. Algorithm 2 demonstrates that creating an initial small core of ablation with rapid coagulation of the center of the lesion allows for equivalent, if not larger, final volumes to be performed in less time.

A simple device for measuring the resolution of videoscopic cameras and laparoscopes in the operating room.

BACKGROUND: There is a need for a device that can be used to objectively evaluate the image quality provided by laparoscopic camera units in the operating room. METHODS: The device that we developed consists of a regular 10-mm or 5-mm laparoscopic port with a rectangular test unit built at the end. A standard test pattern slide with resolution bars is used for measurements. Using this assembly, a single-chip laparoscopic camera was compared with a three-chip laparoscopic camera at different wiring formats and camera settings by measuring the resolution on the monitor screen. RESULTS: Vertical resolution was found to be constant at 550 lines, regardless of the type of camera and wiring used. Of the three wiring formats, composite wiring provided the poorest image with both cameras. When enhancement was off, the horizontal resolution obtained with Y/C or RGB wiring was the same for the one-chip camera at 640 lines of horizontal resolution, whereas RGB cabling provided the best image for the three-chip camera at 800 lines. CONCLUSION: Using basic broadcasting principles, we have developed a simple device that is useful for the comparison of different camera, cabling, and laparoscope configurations in the operating room. This information can be used as objective criteria to judge the image quality in laparoscopic video- systems.

A critical analysis of intraoperative time utilization in laparoscopic adrenalectomy.

BACKGROUND: Time and efficiency analysis is a technique common in industry that is being applied to surgical procedures. The aim of this study is to analyze the time spent performing the component parts of laparoscopic adrenalectomy by both the lateral transabdominal and the posterior retroperitoneal approaches. METHODS: Operational videotapes of 33 patients undergoing laparoscopic adrenalectomy (12 lateral, 21 posterior) were reviewed. The operation was divided into six steps: trocar entry, laparoscopic ultrasonography, exposure of the adrenal gland, dissection of the adrenal, extraction of specimen, and irrigation-aspiration. Time spent for each step and the relation with age, gender, body mass index (BMI), tumor size, side, and histology were assessed using Student's t-test, Pearson correlation, and regression analysis. RESULTS: Although tumor size was larger in the lateral compared to the posterior approach (5.5 vs 2.5 cm, p < 0.001), there was no difference between the groups regarding total operating time (116.1 vs 112.8 min). Most of the operating time was spent on dissection of the adrenal gland with both techniques (lateral, 60%; posterior, 66%). Exposure of the adrenal gland was longer in the lateral compared to the posterior approach (15.1 vs 5.8 min, respectively; p < 0.05). In the transabdominal technique, this step was longer on the right side than on the left (18.9 vs 11.4 min, respectively; p < 0.05). In the lateral approach, dissection time was dependent on tumor size (r = 0.90, p < 0.05) but not on BMI, whereas in the posterior approach both tumor size and BMI were positively correlated (r = 0.56 and r = 0.64, respectively). CONCLUSIONS: To our knowledge, this is the first study to apply time analysis techniques to laparoscopic adrenal surgery. Understanding the variables that affect operative time may influence the choice of the surgical approach in a given patient. This study also suggests that efforts to improve operative efficiency are best directed at the dissection of the adrenal.

Use of the optical access trocar for safe and rapid entry in various laparoscopic procedures.

BACKGROUND: The use of the Veress needle in laparoscopy to create the pneumoperitoneum has inherent risks; it may cause vascular and visceral injuries. The open technique is compromised by the leakage of carbon dioxide and can also be time consuming. One alternative is to enter the abdomen using an optical trocar under direct view. Our aim was to determine whether the optical access trocar can be used to effect a safe and rapid entry in various laparoscopic procedures. METHODS: Over a 4-year period, the Optiview trocar was used for initial entry in 650 laparoscopic procedures. The procedures included cholecystectomy (n = 282), transabdominal inguinal hernia repair (n = 76), radiofrequency ablation of liver tumors (n = 73), adrenalectomy (n = 54), appendectomy (n = 41), colorectal surgery (n = 39), and various other procedures (n = 85). The following parameters were analyzed: presence of previous abdominal operations, site and duration of entry, and complications. RESULTS: Of the 650 patients, 156 (24%) had had previous abdominal operations. In 25 cases, previous trocar sites were reused for optical access. The optical trocar was inserted at the umbilicus in 495 patients (76%), in the right upper quadrant in 77 (12%), in the left upper quadrant in 26 (4%), in the upper midline in eight (1%), in the right lower quadrant in six (0.9%), and in the left lower quadrant in three (0.5%). In 35 patients undergoing posterior adrenalectomy, optical trocars were used to enter Gerota's space. Mean (SD) entry times were 92 (45) sec at the umbilical site, 114 (30) sec at the back, and 77 (35) sec at the remaining sites. Complications (0.3%) included one injury to the bowel and one injury to the gallbladder; however, they were recognized and repaired immediately. CONCLUSIONS: To our knowledge, this report comprises the largest series in which the optical access trocar was used for laparoscopic surgery. This device provides the basis for a safe and fast technique for initial trocar placement: it also has the potential to reduce costs. Thanks to our favorable experience, the optical trocar method has become the standard technique for abdominal access in our laparoscopic practice since 1995.

Understanding and optimizing laparoscopic videosystems.

As tactile feedback and degree of freedom for instrument movement are restricted in laparoscopic surgery, the video image plays the most crucial role in giving the surgeon information about the performance of the operation. The development of small, reliable, high-resolution imaging systems is essential for the surgeon's acquisition detailed information about the tissues being manipulated. Image quality depends on each component of the laparoscopic imaging unit. In this context, it is crucial for the surgeon to have an understanding of how the video signal is formed, transmitted, and displayed. Moreover, the surgeon also needs to have an idea about the basic principles and specifications of the surgical video systems (i.e. charge-coupled device (CCD) camera, monitors, and digitizers). This knowledge is essential for choosing pieces of equipment and knowing how to assemble them into a functional operating suite. The aim of this review is to provide the surgeon with the basics of video signaling, and to familiarize him or her with the technical principles of the surgical video systems. An insight into the future of laparoscopic video systems also is made, and practical tips for improving image quality and troubleshooting are given throughout the article.

Cryoablation, percutaneous alcohol injection, and radiofrequency ablation for treatment of neuroendocrine liver metastases.

Neuroendocrine liver metastases are associated with slow clinical progression, prolonged patient survival, and symptoms of hormone oversecretion. Although surgical resection is the gold standard of treatment, most of the patients are not candidates for resection, and the 5-year survival of patients with neuroendocrine liver metastases is 11% to 40%. Cryotherapy, percutaneous alcohol injection, and radiofrequency thermal ablation are among the alternative regional treatment options available for these patients. The current role of these treatment options for neuroendocrine liver tumors are discussed in this review. Cryosurgery is the classic technique for local tumor destruction, mostly performed with open surgery. There has been limited experience with percutaneous alcohol injection for neuroendocrine liver metastasis. Radiofrequency thermal ablation is a relatively new modality that can be performed percutaneously or laparoscopically, and encouraging results have been obtained with it for treatment of neuroendocrine liver metastases.

Intraoperative thermal regulation in patients undergoing laparoscopic vs open surgical procedures.

BACKGROUND: Although perioperative hypothermia is a well-known consequence of general anesthesia, it has been hypothesized that laparoscopic surgery exacerbates hypothermia to a greater extent than open surgery. The aim of this study was to demonstrate that laparoscopic surgery does not represent an increased risk for hypothermia. METHODS: A case-controlled retrospective study was conducted on 45 patients, 25 undergoing laparoscopic cholecystectomy and 20 undergoing parathyroid surgery under endotracheal general anesthesia. Data were collected regarding age, sex, weight, height, American Society of Anesthesiologists (ASA) status, length of surgery, and anesthesia. In addition, we analyzed the type of intraoperative intravenous fluids, anesthetics and perioperative drugs, and temperature, blood pressure, and heart rate recordings during anesthesia. RESULTS: There was no significant difference between the two groups with respect to age, sex, body mass index (BMI), ASA status, type or amount of intravenous fluids infused, length of anesthesia or surgery, changes in mean blood pressure, or heart rate. Core body temperatures in both groups decreased significantly over time (p 0.05). There was no difference between the groups in terms of maximum drop in temperature (lowest temperature recorded vs baseline temperature) (1.1 +/- 0.7 vs 1.0 +/- 0.7 degrees C, p > 0.05). CONCLUSION: This study demonstrates that patients who undergo laparoscopic and open procedures of similar duration under endotracheal general anesthesia have similar profiles in terms of perioperative hypothermia.

A critical analysis of intraoperative time utilization in laparoscopic cholecystectomy.

BACKGROUND: Most of the expense of laparoscopic cholecystectomy (LC) is incurred while the patient is in the operation room; however, heretofore there has been no critical analysis of the time required to perform the various steps of the operation. An understanding of how operative time is used is the first step toward improving the efficiency of the procedure and decreasing costs while maintaining an acceptable standard of care. METHODS: Of 194 patients undergoing LC at a university hospital between 1994 and 1997, operational videotapes of 48 randomly chosen patients were reviewed. Three groups of patients were identified: those undergoing LC for chronic cholecystitis (n = 27), those undergoing LC for acute cholecystitis (n = 11), and those with common bile duct stones (CBDS), (n = 10) undergoing LC with transcystic common bile duct exploration. The procedure was divided into the following seven steps; trocar entry, laparoscopic ultrasound, dissection of the triangle of Calot, cholangiogram, dissection of the gallbladder, extraction of the gallbladder, and irrigation-aspiration with removal of ports. Time spent for camera cleaning, bleeding control, and insertion of the cholangiocatheter into the cystic duct was also calculated. The groups were compared in terms of time spent for each step using the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The mean +/- SD operating time was 66.5 +/- 20.5 min. The acute group had the longest operating time, followed by the CBDS and chronic groups. Dissection of the gallbladder, insertion of the cholangiocatheter, and irrigation-aspiration were longer steps in the acute group than in the other groups (p < 0.05). Dissection of the triangle of Calot took longer in acute cholecystitis than in chronic cholecystitis (p < 0.05). CBDS cases took longer (p < 0.05) than chronic cases because stone extraction added an average of 17.5 min to the time required for the cholangiogram in chronic cholecystitis. Laparoscopic ultrasound took longer in the CBDS group than in the other groups (p < 0.05). The mean +/- SD time spent for the cholangiogram and laparoscopic ultrasound in chronic cholecystitis was 7.5 +/- 4.3 and 4.8 +/- 1.9 min, respectively. CONCLUSIONS: This time analysis study demonstrates that acute cholecystitis requires a longer operating time because most of the individual steps in the procedure take longer. In patients with choledocholithiasis, stone extraction was responsible for longer operating times. This study should serve as a basis for future studies focusing on time utilization in laparoscopic surgery.

Laparoscopic ultrasonographic appearance of the common bile duct mucosa: a predictor of choledocholithiasis.

Previously we reported on the use of laparoscopic ultrasonography in detecting common bile duct stones during laparoscopic cholecystectomy. The aim of this study is to describe the laparoscopic ultrasonographic appearance of the common bile duct mucosa in patients with choledocholithiasis. Medical records of 44 patients with an increased risk for common bile duct stones undergoing laparoscopic cholecystectomy between 1993 and 1998 were reviewed. In the operating room, the laparoscopic ultrasonographic appearance of the common bile duct mucosa was scored in real time as normal, mild changes (hyperechoic mucosa), or severe changes (hyperechoic with mucosal thickening). Of the 31 patients (70%) with stones or sludge in the biliary tree, 29 (94%) had either severe (58%) or mild (36%) hyperechoic and 2 (6%) had normal-appearing common bile duct mucosa on laparoscopic ultrasonography. Of the 13 patients (30%) with no documented stones or sludge, 11 (85%) had normal and 2 (15%) had mild hyperechoic common bile duct mucosa on laparoscopic ultrasonography. Both of these patients had laboratory values indicating recent passage of common bile duct stones. The association between common bile duct stones and the presence of hyperechoic common bile duct mucosa was statistically significant (P < .0001, Fisher's exact test). This is the first report of hyperechoic common bile duct mucosa demonstrated by laparoscopic ultrasonography as a predictor of common bile duct stones. This finding is evident in the majority of patients with common bile duct stones and also may be associated with recent passage of a stone into the duodenum.

Use of CT Hounsfield unit density to identify ablated tumor after laparoscopic radiofrequency ablation of hepatic tumors.

BACKGROUND: When attempting to interpret CT scans after radiofrequency thermal ablation (RFA) of liver tumors, it is sometimes difficult to distinguish ablated from viable tumor tissue. Identification of the two types of tissue is specially problematic for lesions that are hypodense before ablation. The aim of this study was to determine whether quantitative Hounsfield unit (HU) density measurements can be used to document the lack of tumor perfusion and thereby identify ablated tissue. METHODS: Liver spiral CT scans of 13 patients with 51 lesions undergoing laparoscopic RFA for metastatic liver tumors within a 2-year time period were reviewed. HU density of the lesions as well as normal liver were measured pre- and postoperatively in each CT phase (noncontrast, arterial, portovenous). Statistical analyses were performed using Student's paired t-test and ANOVA. RESULTS: Normal liver parenchyma, which was used as a control, showed a similar increase with contrast injection in both pre- and postprocedure CT scans (56.4 +/- 2.4 vs 57.1 +/- 2.4 HU, respectively; p = 0.3). In contrast, ablated liver lesions showed a preablation increase of 45.7 +/- 3.4 HU but only a minimal postablation increase of 6.6 +/- 0.7 HU (p < 0.0001). This was true for highly vascular tumors (neuroendocrine) as well as hypovascular ones (adenocarcinoma). CONCLUSIONS: This is the first study to define quantitative radiological criteria using HU density for the evaluation of ablated tissues. A lack of increase in HU density with contrast injection indicates necrotic tissue, whereas perfused tissue shows an increase in HU density. This technique can be used in the evaluation of patients undergoing RFA.

Laparoscopic ultrasound vs triphasic computed tomography for detecting liver tumors.

BACKGROUND: Accurate staging of malignant tumors in the liver has major implications in defining prognosis and guiding both surgical and nonsurgical therapy. Intraoperative ultrasound in open surgery compares favorably with computed tomography (CT) in the detection of liver tumors; however, there is little experience with laparoscopic ultrasound (LUS). HYPOTHESIS: Laparoscopic ultrasound is more sensitive than triphasic CT for detecting primary and metastatic liver tumors. DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Fifty-five patients with a total of 222 lesions, including primary and metastatic liver tumors, who underwent both CT examinations and LUS as a part of a tumor ablation procedure. INTERVENTIONS: Triphasic spiral CT scans of the liver were obtained within 1 week before surgery. Liver LUS was performed with a linear 7.5-MHz side-viewing laparoscopic transducer. RESULTS: The LUS detected all 201 tumors seen on preoperative CT and detected 21 additional tumors (9.5%) in 11 patients (20.0%). These tumors missed by CT ranged in size from 0.3 to 2.7 cm. Smaller tumors tended to be missed by CT scan (28.6% of the lesions <1 cm, 15.8% of those 1-2 cm, 4% of those 2-3 cm, and 0% of those >3 cm), as did those in segments III and IV. There was good correlation between the size of lesions imaged by the 2 modalities (Pearson r = 0.86; P<.001). CONCLUSION: Laparoscopic ultrasound offers increased sensitivity over CT for the detection of liver tumors, especially for smaller lesions. This study documents the ability of LUS in detecting liver tumors and argues for more widespread use in laparoscopic staging procedures.

Laparoscopic posterior adrenalectomy: technical considerations.

HYPOTHESIS: Although laparoscopic posterior adrenalectomy (LPA) offers a more direct access to the adrenal gland, it is not as popular as laparoscopic transabdominal adrenalectomy, and the worldwide experience has been limited. We hypothesized that LPA is a safe and efficacious procedure that could best serve certain patients with adrenal tumors. DESIGN: Case series of patients undergoing laparoscopic adrenalectomy in a single institution. SETTING: University teaching hospital. PATIENTS: Medical records of 31 patients with 33 tumors who underwent LPA were reviewed. Indications for operation included hormone secretion in 23 patients (74%), suspected or known malignant neoplasms in 7 patients (23%), and local symptoms in 1 patient (3%). INTERVENTION: The LPAs were performed with the patients in prone position. Preoperative ultrasonography localized the adrenal tumor and kidney to guide balloon trocar placement for the creation of a working retroperitoneal space. The LPAs were performed with three 10-mm trocars using laparoscopic ultrasound to localize the tumor and the harmonic scalpel to perform the dissection. MAIN OUTCOME MEASURES: Demographic data, type and size of tumor, operative time, blood loss, intraoperative and postoperative complications, and hospital stay were analyzed. RESULTS: All operations were successfully completed without conversion. Excluding the bilateral cases, the mean +/- SD operative time was 176 +/- 104 minutes. Estimated blood loss averaged 32 mL (range, 10-200 mL). There were no intraoperative complications. The mean +/- SD tumor size was 3.2 +/- 1.8 cm (range, 0.8-7.0 cm). Pathological evaluation revealed benign tumors in 25 patients (81%) and malignant tumors in 6 patients. The average hospital stay was 1.4 days (range, 1-3 days). There were no deaths. CONCLUSIONS: Although technically more demanding, LPA should be considered in patients with tumors less than 6 cm, bilateral tumors, or extensive previous abdominal surgery.

Laparoscopic treatment of hepatic hydatid cysts.

BACKGROUND: Because of limited experience worldwide, controversies about the laparoscopic treatment of liver hydatid cysts have not been resolved. The aim of this study was to describe the technical details of a laparoscopic method we developed in 1992 and report the initial results from an endemic area. METHODS: Of the 30 consecutive patients with 33 liver hydatid cysts considered for laparoscopic treatment during a 6-year period at a university hospital in Turkey, conversion to an open procedure was required in 7 patients (23%) while 23 patients with 25 cysts were able to be treated laparoscopically. RESULTS: By using a special trocar to suspend the cyst against the abdominal wall, laparoscopic simple drainage was performed in 16 patients (70%) and unroofing and drainage in 6 patients (26%). Pericystectomy was performed in 1 patient (4%). Complications were observed in 1 patient (4%) perioperatively and 4 patients (17%) postoperatively. Eleven patients (48%) were followed-up for a mean of 17 months (range, 3-72 months) and 1 recurrence (9%) was detected. CONCLUSIONS: This report is a very large experience with the laparoscopic treatment of liver hydatid cysts in the literature. We have established a technique yielding a comparable morbidity and recurrence rate to open series in early follow-up. We advocate that it is a safe and simple technique with potentially a decreased risk of intra-abdominal spillage compared with the other laparoscopic methods described.

Laparoscopic radiofrequency ablation of primary and metastatic liver tumors. Technical considerations.

BACKGROUND: Radiofrequency thermal ablation is a new technology for the local destruction of liver tumors. Since we first described laparoscopic radiofrequency ablation (LRFA) for the treatment of liver tumors, much has been learned about patient selection, laparoscopic ultrasound (LU) guided placement of the ablation catheter, monitoring of the ablation process, and patient follow-up. METHODS: Since January 1996 we have performed LRFA of 250 tumors in 67 patients including 85 adenocarcinomas, 107 neuroendocrine tumors, 34 sarcomas, 1 melanoma, and 11 hepatomas. We used LU to guide placement of the ablation catheter and to monitor the ablation process. Most of the patients had two trocars (camera and laparoscopic ultrasound) with the 15-gauge ablation catheter (RITA Medical Systems, Mountain View, CA, USA) placed percutaneously. RESULTS: The LRFA procedure was completed successfully in all patients, with 1 to 14 lesions per patient, ranging in size from 0.5 to 10 cm in diameter. The entire liver could be examined by LU via right subcostal ports. Criteria for successful ablation were 5-min ablation times at 100 degrees C with 1-min cool-down temperatures of 60 degrees to 70 degrees C. Outgassing of dissolved nitrogen, monitored by ultrasound, was useful in confirming the zone of ablation. Intralesional color-flow Doppler, seen before ablation, was eliminated after ablation. Placement of the grounding pad closer to the lesion on the back rather than the thigh resulted in more efficient energy delivery to the tumor. Lesions larger than 3 cm in diameter required overlapping ablations to achieve a 1-cm margin of normal liver. Most patients required overnight hospitalization, with no coagulopathy or electrolyte disturbances noted. CONCLUSIONS: The LRFA procedure is a novel, minimally invasive technique for treatment of liver tumors that have failed conventional therapy. This study documents the technical aspects of targeting lesions and performing reproducible zones of ablation. Familiarity with these techniques should lead to more widespread application.