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. Presented at the AHPBA 2005 Congress on 4/14–17/2005 in Ft. Lauderdale, Florida as a poster     

The radiographic evolution of radio frequency ablated renal tumors

PURPOSE: Radio frequency ablation (RFA) of renal tumors is a relatively new technology. Few groups are familiar with the posttreatment appearance of these lesions and how they differ from cryoablated renal masses. We describe the evolution of the appearance of these lesions on followup contrast enhanced (CE) computerized tomography (CT). METHODS AND MATERIALS: A total of 64 consecutive renal tumors treated with RFA from April 2000 to September 2003 for which posttreatment CE-CT was done were included in this study. CE-CT was reviewed at 6 weeks, 3 months, 6 months and every 6 months thereafter to determine the characteristic features and evolution of these lesions. RESULTS: Renal tumors were treated with CT guided percutaneous (34), laparoscopic (28) or open (2) RFA. At a median followup of 13.7 months (range 6 weeks to 29 months) 62 RFA lesions demonstrated an absence of contrast enhancement on CE-CT. Treated endophytic tumors developed a low density, nonenhancing, wedge-shaped defect with fat infiltration seen between the ablated tissue and normal parenchyma. Treated exophytic tumors retained a configuration similar to that of the original with a lack of contrast enhancement and minimal shrinkage. Percutaneous treated lesions developed a peritumor scar or halo that demarcated ablated and nonablated tissue (perirenal fat). Persistent tumor was marked by contrast enhancement within the ablation borders of the original mass in 1 case, whereas tumor recurred after initial successful ablation with an enhancing nodule in 1. CONCLUSIONS: The radiographic features and evolution of radio frequency ablated renal tumors are unique. Successfully treated tumors demonstrated no contrast enhancement, minimal shrinkage and occasional retraction from normal parenchyma by fat infiltration.     

A serum-soluble factor(s) stimulates tumor growth following laparotomy in a murine modelrid=""id=""Presented at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), San Antonio, TX, 26 March 1999

Background: Our laboratory and others have previously demonstrated that tumors grow larger and are more easily established following laparotomy than after CO₂ pneumoperitoneum. The etiology of increased tumor growth after surgery is unknown. We hypothesized that, following laparotomy, a serum soluble factor(s) is generated that causes tumors to proliferate more rapidly. The purpose of the current study was to determine if in vitro tumor cells proliferate faster when incubated with serum from laparotomized mice than cells incubated with sera from mice who have undergone CO₂ pneumoperitoneum or anesthesia alone. Methods: In the first experiment, female Balb/C mice (n= 84) were randomly divided into the following three groups: (a) control (AC), (b) CO₂ insufflation (INS), and (c) laparotomy (OPEN). The AC mice underwent no procedure. The INS group underwent CO₂ pneumoperitoneum at 4–6 mmHg for 20 min. The OPEN group had a midline incision from xiphoid to pubis. The serum of seven mice from each group were collected on postoperative days (POD) 1, 2, 4, and 7 via a cardiac puncture. The sera at each time point for each group were pooled. Twenty thousand C-26 colon cancer cells were incubated separately in growth media containing 10% mouse serum from each group (seven determinations/group) at each time point. In the second experiment, female Balb/C (n= 30) mice were divided into AC and OPEN groups. On POD4, sera were collected and pooled. Three separate studies were performed for the second experiment. In the first study, tumor cells were incubated with 10% AC sera or varying concentrations of OPEN mice sera (4–10%). In the second study, aliquots of sera from the OPEN group mice were then heated at 100°C for 1 or 5 min. Tumors were then incubated separately in media with 10% AC, OPEN, or heated OPEN group sera. In the third study, aliquots of sera from the OPEN group mice were dialyzed against PBS through a 3.5-kD or an 8-kD dialysis membrane tubing for 24 h. Tumors were then incubated separately in media with 10% AC, OPEN, or dialyzed OPEN group sera. For both experiments, tumor proliferation was determined and compared between groups after 72 h of incubation. Results: Tumor cells incubated with POD2 and POD4 sera from OPEN group mice proliferated twice as fast as those incubated with sera from either AC or INS group mice. The difference in proliferation was maximal on POD4 and started to decline by POD7. Proliferative activity from the OPEN group sera decreased significantly when heated for 1 min and was completely ablated after 5 min of heating. Proliferative activity from the OPEN group sera was completely ablated after dialysis. Conclusions: We conclude that there is a serum-soluble factor(s) present postoperatively that stimulates tumors to grow significantly faster after laparotomy. The mitogenic effect of laparotomized mice sera is dilutable. It is uncertain whether the factor is heat labile, since heating most likely destroys other necessary proteins in the sera. The size of the factor is undeterminable using the dialysis method. Further efforts to identify these factors are currently underway. Received: 8 February 1999/Accepted: 23 June 1999/Online publication: 24 March 2000     

Experimental development and validation of a technique for lumboendoscopic anterior fusion of lumbar spine fracturesrid=""

Background: Using a porcine model, this study describes the feasibility of a lumboendoscopically guided approach to the lumbar spine for anterior interbody fusion, and compares the results with that of the open procedure. The objectives of this study were to develop a minimally invasive approach to the lumbar spine for anterior fusion in pigs, and to test the validity and safety of the procedure in this porcine model. Besides posterior stabilization, considerable number of thoracolumbar spine (Th12–L5) fractures require intervention for anterior fusion to prevent loss of height of the injured segment and kyphotic deformation. Because anterior fusion needs major surgery (thoracophrenolumbotomy for Th12–L1), which is associated with high morbidity, this study aimed to develop a less traumatic minimally invasive approach. Methods: Six pigs under balanced anesthesia were used to study the feasibility of the lumboendoscopic approach for bisegmental fusion (iliac crest bone block and dynamic compression plate) from Th15 to L6. In an additional six animals, lumboendoscopic fusion was performed at the level of diaphragm insertion (Th14–Th16), representing Th12–L1 in patients. For comparative analysis, six animals undergoing open thoracophrenolumbotomy and anterior Th14–Th16 fusion served as control subjects. Results: Endoscopic anterior fusion could be successfully performed at all levels of the thoracolumbar spine without major complications. In three cases, unintended opening of the peritoneal cavity was observed, however, without the operative procedure being affected. Comparative analysis revealed a significantly longer p < 0.01 operation time (126 ± 6.5 min) and increased femoral vein pressure (11.3 ± 0.7 mmHg) in animals undergoing endoscopic surgery (open procedure, 76.0 ± 11.6 min and 5.2 ± 0.5 mmHg). However, the microvascular blood supply (perfusion) to the distal extremities, as assessed by laser Doppler flowmetry, was not affected. Conclusions: Our study demonstrates that lumboendoscopic anterior spine fusion in pigs is feasible at all levels from Th14 to L6, and can be performed in an acceptable operation time without major complications. Received: 8 April 1999 /Accepted: 27 April 2000 /Online publication: 20 July 2000     

Time-related changes in hemodynamic parameters and pressure-derived indices of left ventricular function in a porcine model of prolonged pneumoperitoneum

Background: Advanced laparoscopic procedures require prolonged pneumoperitoneum. Increased intra-abdominal pressure causes a number of hemodynamic changes including a drop in cardiac output, but it is unclear whether there is a direct effect on cardiac contractility. In this experimental study, we sought to determine whether there is a direct impact of pneumoperitoneum on cardiac contractility. We also examined the time-related changes taking place during the insufflation period. Methods: Six young pigs were anesthetized and mechanically ventilated. Pneumoperitoneum was established by insufflating carbon dioxide to a pressure of 15 mmHg and maintained for a period of 180 min. Hemodynamic parameters including left ventricular dP/dT were invasively recorded every 15 min. All hemodynamic changes were statistically evaluated, and parameters were correlated with time. Results: Cardiac output decreased with insufflation from a baseline of 3.37 ± 0.34 lt/min and reached the lowest value at 165 min of pneumoperitoneum (2.86 ± 0.30 l/min; p= 0.023). Systemic vascular resistance (SVR) significantly increased from 2236 ± 227 dyne/s/cm⁵ to a maximum of 3774 ± 324 dyne/s/cm⁵ (p= 0.005). Left ventricular dP/dT maximum did not change significantly with insufflation. The decrease in cardiac output strongly correlated with the increase in SVR (r=−0.949). Time of insufflation correlated with cardiac output (r=−0.762) and dP/dT maximum (r=−0.727). Conclusions: Pneumoperitoneum at 15 mmHg negatively affects cardiac output without significantly affecting cardiac contractility. A significant increase in SVR appears to be the driving event for the decreased cardiac output. Prolonged pneumoperitoneum may have an additional negative effect on hemodynamic parameters. Received: 5 January 2000/Accepted: 4 May 2000/Online publication: 26 July 2000     

Laparoscopic insufflation of the abdomen reduces portal venous flow

Background: The adverse effects of sustained elevated intraperitoneal pressure (IPP) on cardiovascular, pulmonary and renal systems have been well documented by several reported experimental and clinical studies. Alteration in the splanchnic circulation has also been reported in animal experiments, but details of the exact hemodynamic changes in the flow to solid intraabdominal organs brought on by a raised intraperitoneal pressure in the human are not available. The aim of the present study was to estimate effect of increased IPP on the portal venous flow, using duplex Doppler ultrasonography in patients undergoing laparoscopic cholecystectomy. Methods: The studies were performed using the SSD 2000 Multiview Ultrasound Scanner and the UST 5536 7.0-MHz laparoscopic transducer probe. Details of the measurements were standardized in according to preset protocol. Statistical evaluation of the data was conducted by the two-way analysis of variance (ANOVA). Results: The flow measurement data have demonstrated a significant (p < 0.001) decrease in the portal flow with increase in the intraperitoneal pressure. The mean portal flow fell from 990 ± 100 ml/min to 568 ± 81 ml/min (−37%) at an IPP of 7.0 mmHg and to 440 ± 56 mmHg (−53%) when the IPP reached 14 mmHg. Conclusions: The increased intraperitoneal pressure necessary to perform laparoscopic operations reduces substantially the portal venous flow. The extent of the volume flow reduction is related to the level of intraperitoneal pressure. This reduction of flow may depress the hepatic reticular endothelial function (possibly enhancing tumor cell spread). In contrast, the reduced portal flow may enhance cryo-ablative effect during laparoscopic cryosurgery for metastatic liver disease by diminishing the heat sink effect. These findings suggest the need for a selective policy, low pressure or gas-less techniques to positive-pressure interventions, during laparoscopic surgery in accordance with the disease and the therapeutic intent. Received: 19 March 1996/Accepted: 4 July 1997     

The physiologic effect of the pneumoperitoneum on radiofrequency ablation

Background: Radiofrequency ablation (RFA) is gaining widespread acceptance as a safe and effective method for liver tumor ablation. Complete tumor ablation is essential for the success of the procedure. Multiple modalities have been explored in an effort to increase the size of the lesion created by RFA. The purpose of this study was to determine the physiologic effects of the pneumoperitoneum on RFA lesion size. Methods: A total of 32 RFA lesions were created in eight pigs. After the induction of anesthesia, pneumoperitoneums of 2, 12, and 24 mmHg were established sequentially in each animal. After an equilibration period of 2 min, RF was administered with a constant saline-infused (0.9%) needle at 25 W for 3 min. In subsequent and complementary experiments, both before and during RF administration at each intraperitoneal pressure (IPP), Doppler flow was measured by laparoscopic ultrasound in the portal vein and hepatic artery while blood pressure was monitored by a femoral arterial line. The animals were then killed humanely and the livers were harvested. Measurements were taken in three dimensions of the ablated areas, and the volume was calculated. Statistical analyses were performed using analysis of variance (ANOVA) and repeated measures test. Results: The average volumes of the lesions (in cm³) were 3.1 ± 1.8, 5.2 ± 1.7, and 6.7 ± 3.3 for IPP of 2, 12 and 24 mmHg, respectively; there was a significant difference between the area of lesion at an IPP of 2 mmHg and an IPP of 24 mmHg (p < 0.05). Blood flow in the portal vein also decreased significantly from 1.8 ± 0.6, 0.98 ± 0.5, and 0.43 ± 0.2 at IPP of 2, 12, and 24 mmHg, respectively (p < 0.001). Hepatic artery blood flow and peripheral blood pressure did not change significantly in the respective IPP groups. Conclusions: This study indicates that the volume of liver ablated by RF can be increased by augmenting the IPP. Our data support the theory that a decrease in portal blood flow results in decreased heat dissipation during RFA. The laparoscopic approach to RFA offers the advantage of allowing control of the IPP, which may result in a larger volume of ablated tissue per treatment than can be achieved with the percutaneous technique. These preliminary data on normal hepatic tissue must be confirmed clinically in the setting of hepatic tumors.     

Higher Osteocalcin Levels and Cross-Links Excretion in Young Men Born with Low Birth Weight

As the result of accelerated growth, the final height of infants born with low birth weight (LBW) is near to the normal. Limited data are available about the bone density and bone turnover just after completion of skeletal development. We have investigated the bone turnover and bone density in 49 apparently healthy young LBW men (age 19–21 years; 21 born small for gestational age (SGA) and 28 appropriate for gestational age (AGA)) and in 16 age-matched controls. Bone mineral density of lumbar spine, femoral neck, and radius midshaft, the markers of calcium homeostasis, biochemical parameters of bone turnover as serum osteocalcin (OC), and urinary pyridinoline (PYD) and deoxypyridinoline (DPD) levels were measured. Bone mineral densities of LBW subjects were not altered. Serum calcium (SGA: 2.44 ± 0.15; AGA:2.41 ± 0.17, control: 2.25 ± 0.09 mmol/liter, P < 0.05), OC (SGA:23.4 ± 9.9; AGA:20.8 ± 7.6; control:13.3 ± 4.6 ng/ml, P < 0.01), total alkaline phosphatase (AP) (SGA:201 ± 61; AGA:193 ± 81, control:117 ± 34 IU/liter, P < 0.01), and urinary DPD/creat (ln.values: SGA:3.10 ± 0.48; AGA:3.17 ± 0.46; control:2.58 ± 0.57 nmol/mmol, P < 0.05) were higher, whereas fractional excretion of calcium (SGA:0.94 ± 0.470; AGA:1.03 ± 0.51, control:1.31 ± 0.75%, P < 0.05) was lower in both SGA and AGA groups. PTH and 25OHD were not different. Significant correlation was obtained between seCa, OC, AP, DPD and birth weight of the subjects, but feCa correlated inversely to the birth weight. It was concluded that the bone turnover of LBW men is accelerated, but well balanced in young adulthood. Further investigation is needed to describe the possible link between accelerated bone turnover and hormonal homeostasis of LBW subjects. Received: 30 November 1999 / Accepted: 9 September 2000 / Online publication: 22 December 2000     

Radio frequency ablation of small renal tumors:: intermediate results

Purpose

With evolving radio frequency technology, the clinical application of radio frequency ablation (RFA) has been actively investigated in the treatment for small renal tumors. We present our intermediate patient outcomes after RFA.

Materials and Methods

Since January 2001, 17 patients with a total of 24 hereditary renal tumors ranging from 1.2 to 2.85 cm were treated with RFA using the 200 W Cool-tip RF System (Radionics, Burlington, Massachusetts) under laparoscopic (9) or percutaneous (8) guidance and had a minimum 1-year followup. A percutaneous approach was considered unsuitable if kidney tumors were contiguous to bowel, ureter or large vessels. Treatment eligibility criteria included an average tumor diameter of less than 3.0 cm, tumor growth during 1 year and solid appearance with contrast enhancement (HU change greater than 20) on computerized tomography (CT). Postoperative followup consisted of CT with and without intravenous contrast, and renal function assessment at regular intervals.

Results

Median patient age was 38 years (range 20 to 51). At a median followup of 385 days (range 342 to 691), median tumor or thermal lesion diameter decreased from 2.26 to 1.62 cm (p = 0.0013), and only 1 lesion (4%), which was located centrally near the hilum, exhibited contrast enhancement (HU change greater than 10) on CT at 12 months. Of the 15 renal tumors ablated laparoscopically, 13 were in direct contact with the bowel and 2 were abutting the ureter, necessitating mobilization before RFA. Laparoscopic ultrasound was used to guide radio frequency electrode placement and monitor the ablation process in these cases. Operative time and intraoperative blood loss (mean ± standard mean of error) were 243 ± 29 minutes and 67 ± 9 cc, respectively. In 1 patient whose ureter was adherent to the tumor a ureteropelvic junction obstruction developed after laparoscopic RFA, requiring open repair.

Conclusions

At the minimum 1-year followup 23 of 24 ablated tumors lacked contrast uptake on CT, meeting our radiographic criteria of successful RFA treatment. RFA treatment of small renal tumors using the Radionics system appears to result in superior treatment outcomes compared to those of earlier series with lower radio frequency power generators. A high wattage generator might attain more consistent energy deposition with subsequent cell death in the targeted tissue due to less convective heat loss.     

Osteoporosis and Bone Mineral Metabolism Disorders in Cirrhotic Patients Referred for Orthotopic Liver Transplantation

The purpose of this study was to determine the prevalence of osteoporosis, to estimate the bone turnover and hormonal status, and to identify the factors associated with bone disease in patients with end-stage liver disease who were referred for orthotopic liver transplantation. A prospective study was performed on 58 cirrhotic patients (6 with primary biliary cirrhosis, 14 with alcoholic cirrhosis, and 38 with posthepatitic cirrhosis), who were referred for orthotopic liver transplantation. Patients, excluding those with primary biliary cirrhosis, were classified in Child-Pugh groups according to the severity of liver disease (class B [28 patients], class C [24 patients]). Biochemical parameters of bone mineral metabolism and standard liver function tests were measured in all patients. Additionally, serum osteocalcin, urinary hydroxyproline/creatinine ratio, serum intact parathyroid hormone, serum 25-hydroxyvitamin D, serum 1,25-dihydroxyvitamin D, folliclestimulating hormone, and luteinizing hormone levels were determined in patients and controls within the same age range. Plasma testosterone, sex hormone-binding globulin levels, and free testosterone index were obtained for all men included in the study. Bone mass of the lumbar spine and femur were measured by dual X-ray absorptiometry (DPX-L), and were expressed as a standard deviation of mean values (Z-score) from a sex and age-matched control group. Spinal X-rays were obtained to assess vertebral fractures. Osteoporosis was considered as a factor in spinal bone mineral density with a Z-score below 2 or at least one vertebral fracture. Twenty-five patients (43%) had osteoporosis, with lower bone mass measurements in the lumbar spine than in the femoral neck (P < 0.005). Alcoholic and Child-Pugh C patients showed the lowest femoral bone mineral density values. Cirrhotic patients showed lower osteocalcin levels than controls (14.3 ± 5.9 vs. 18.2 ± 8.1 ng/ml; P < 0.05) and showed increased urinary hydroxyproline (125.1 ± 51.5 vs. 107.9 ± 26.6 nM/mg creatinine; P < 0.05). Serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and parathyroid hormone levels were significantly lower in cirrhotic patients than in controls (10.3 ± 9.1 vs. 23.1 ± 26.6 ng/ml; P= 0.000), (12.9 ± 9.1 vs. 48.3 ± 11.5 pg/ml; P= 0.000), (16.6 ± 9.2 vs. 27.9 ± 8.2 pg/ml; P= 0.000), with no differences between Child-Pugh groups. Alcoholic Child-Pugh C patients showed the lowest 25-hydroxyvitamin D serum values (4.5 ± 2.2 ng/ml; P < 0.05). Male patients had lower testosterone levels than controls (302.5 ± 229.4 vs. 556.7 ± 146.5 ng/dl; P= 0.000), with increased sex hormone-binding globulin values. Levels of testosterone and gonadotropin were related to Child-Pugh classification. No correlation was found between bone mass and hormonal values. A significant decrease in bone mass, particularly in the lumbar spine, is seen in end-stage cirrhotic patients. Reduced bone formation and significant disorders of bone mineral metabolism, such as vitamin D deficiency, reduced parathyroid hormone levels, and hypogonadism are involved. Moreover, severity and etiology of the liver disease are the main risk factors for developing bone loss and mineral metabolism disorders in patients referred for orthotopic liver transplantation. Received: 7 March 1996 / Accepted: 24 June 1996     

Technical advances toward interactive image-guided laparoscopic surgery

Background: Laparoscopic surgery uses real-time video to display the operative field. Interactive image-guided surgery (IIGS) is the real-time display of surgical instrument location on corresponding computed tomography (CT) scans or magnetic resonance images (MRI). We hypothesize that laparoscopic IIGS technologies can be combined to offer guidance for general surgery and, in particular, hepatic procedures. Tumor information determined from CT imaging can be overlayed onto laparoscopic video imaging to allow more precise resection or ablation. Methods: We mapped three-dimensional (3D) physical space to 2D laparoscopic video space using a common mathematical formula. Inherent distortions present in the video images were quantified and then corrected to determine their effect on this 3D to 2D mapping. Results: Errors in mapping 3D physical space to 2D video image space ranged from 0.65 to 2.75 mm. Conclusions: Laparoscopic IIGS allows accurate (<3.0 mm) confirmation of 3D physical space points on video images. This in combination with accurately tracked instruments and an appropriate display may facilitate enhanced image guidance during laparoscopy. Received: 30 April 1999/Accepted: 10 November 1999/Online publication: 8 May 2000     

Laparoscopyrid=""

Background: Although many aspects of laparoscopic surgery have been determined, the question of which insufflation gas is the best arises repeatedly. The aim of this study was to review the findings on the major gases used today in order to provide information and guidelines for the laparoscopic surgeon. Methods: We reviewed the literature for clinical and laboratory studies on the currently used laparoscopic insufflation gases: carbon dioxide (CO₂), nitrous oxide (N₂O), helium (He), air, nitrogen (N₂), and argon (Ar). The following parameters were evaluated: acid–base changes, hemodynamic and respiratory sequelae, hepatic and renal blood flow changes, increase in intracranial pressure, outcome of venous emboli, and port-site tumor growth. Results: The major advantage of CO₂ is its rapid dissolution in the event of venous emboli. Hemodynamic and acid–base changes with CO₂ insufflation usually are mild and clinically negligible for most patients. Although N₂O is advantageous for procedures requiring local/regional anesthesia, it does not suppress combustion. Findings show that Ar may have unwanted hemodynamic effects, especially on hepatic blood flow. There are almost no hemodynamic or acid-base sequelae with the use of He, air, and N₂, but they dissolve slowly and carry a potential risk of lethal venous emboli. Conclusions: Clearly, CO₂ maintains its role as the primary insufflation gas in laparoscopy, but N₂O has a role in some cases of depressed pulmonary function or in local/regional anesthesia cases. Other gases have no significant advantage over CO₂ or N₂O and should be used only in protocol studies. The relation of port-site metastasis to a specific type of gas requires further research. Received: 16 January 2000/Accepted: 15 March 2000/Online publication: 22 August 2000     

Lateral Spine Densitometry in Obese Women

The lateral (LAT) spine scan has been suggested as a more sensitive measure than posterior-anterior (PA) scanning for assessing age-related bone loss in normal-weight postmenopausal women. The measurement error of PA and LAT bone mineral density (BMD) using dual energy X-ray absorptiometry (DXA) has also been shown to rise with incremental increases in fat and from large variance in fat thickness, respectively. The purpose of this cross-sectional study was to determine specific affects of obesity on paired PA and LAT lumbar (L₂–L₄) BMD and Z score (BMD of patient versus age-matched reference database) correlation in 30 obese postmenopausal women (mean BMI ± SD = 33.3 ± 4.06). The mean PA and LAT BMD ± SD were 0.946 ± 0.123 and 0.749 ± 0.134, respectively. The mean PA and LAT Z scores were −0.17 ± 1.15 and 0.80 ± 1.7. The correlation between PA and LAT BMD was significantly lower (r = 0.55; P < 0.05) than previously reported, and PA and LAT Z score correlation was (r = 0.57; P= 0.0016). After adjusting for body mass index (BMI), percent body fat, fat mass, and truncal fat by DXA, waist:hip ratio (WHR) and visceral and subcutaneous abdominal fat by computerized axial tomography (CT), PA and LAT Z score correlation increased to r = 0.62; P= 0.0065. In our subjects, the mean LAT Z score was 4.6 times higher than the mean AP Z, contrary to previous observations in normal-weight postmenopausal women. Our findings may be due to increased soft tissue composition and fat inhomogeneity in the LAT scanning field resulting in increased X-ray attenuation in obesity. Received: 22 July 1997 / Accepted: 26 January 1998     

Thoracoscopic enucleation of benign tumors of the esophagus under simultaneous flexible esophagoscopy

Background: Benign tumors of the esophagus are very rare, accounting for only 0.1–2% of all esophageal tumors. Conventional treatment consists of thoracotomy adapted to the location of the tumor, followed by enucleation of the lesion. This approach, however, involves major surgery. Minimally invasive surgery represents a viable therapeutic alternative, in particular for benign tumors. Methods: In four patients with a benign tumor of the esophagus, we carried out thoracoscopic enucleation under simultaneous esophagoscopy. Results: Using this combination of endoscopic procedures, the tumors were removed reliably and safely. Two of the lesions were intramural leiomyomas, and two were intramural myxoid cysts. Conclusion: This combination of endoscopic procedures represents a minimally invasive approach with correspondingly minor surgical trauma. Using simultaneous esophagoscopy and transillumination (diaphanoscopy) of the esophageal wall, the safety and accuracy of the dissection is increased, and the risk of mucosal perforation minimized. Received: 10 January 2000/Accepted: 30 March 2000/Online publication: 29 August 2000     

Prospective comparison of endorectal ultrasound, three-dimensional endorectal ultrasound, and endorectal MRI in the preoperative evaluation of rectal tumorsrid=""

Background: The aim of this study was to compare the value of endorectal ultrasound (EUS), three-dimensional (3D) EUS, and endorectal MRI in the preoperative staging of rectal neoplasms. Methods: Thirty consecutive patients with rectal tumors were assessed by EUS and endorectal MRI. Additionally, three-dimensional ultrasound was performed in a subgroup of 25 patients. EUS data were obtained with a bifocal multiplane transducer (10 MHz) and processed on a 3D ultrasound workstation. MR imaging was carried out with a 1.5 T superconducting unit using an endorectal surface coil. Results: EUS was carried out successfully in all 30 patients, whereas endorectal MRI was not feasible in two patients. Compared with the histopathological classification, EUS and endorectal MRI correctly determined the tumor infiltration depth in 25 of 30 and 28 patients, respectively. The comparative accuracy of EUS, 3D EUS, and endorectal MRI in predicting tumor invasion was 84%, 88%, and 91%, respectively. EUS, three-dimensional EUS, and endorectal MRI enabled us to assess the lymph node status correctly in 25, 25, and 24 patients, respectively. Both three-dimensional EUS and endorectal MRI combined high-resolution imaging and multiplanar display options. Assessment of additional scan planes facilitated the interpretation of the findings and improved the understanding of the three-dimensional anatomy. Conclusion: The accuracy of three-dimensional EUS and endorectal MRI in the assessment of the infiltration depth of rectal cancer is comparable to conventional EUS. One advantage of both methods is the ability to obtain multiplanar images, which may be helpful for the planning of surgery in the future. Received: 4 April 2000/Accepted: 25 August 2000/Online publication: 27 October 2000     

Port site tumor recurrence rates in a murine model of laparoscopic splenectomy decreased with increased experiencerid=""id=""Presented at the sixth International Congress of the European Association of Endoscopic Surgery (E.A.E.S.), Rome, Italy, 5 June 1998

Background: The etiology of port site tumor recurrences following laparoscopic surgery for cancer remains unknown. A recent study from our laboratory using a murine splenic tumor model suggests that it is poor surgical technique (i.e., crushing of the tumor) rather than the CO₂ pneumoperitoneum that is responsible for these tumors. However, in that experiment, no intraabdominal procedure was carried out. We subsequently performed a preliminary study in which we compared the rate of port site tumor recurrences after laparoscopic-assisted splenectomy (LAS) vs open splenectomy (OS) using the murine splenic tumor model. In this study, we found significantly more port and incisional tumors after laparoscopic splenectomy. The reasons for this finding are unclear. Further analysis of the data showed that the incidence of port tumors in the LAS group decreased dramatically from the first to the second trial, suggesting that the experience of the surgeon may play a role. The purpose of the current study was to carry out further trials to determine if the lower rate of port tumor recurrence in the laparoscopic group will persist with increased surgical experience. Methods: Splenic tumors were established in female Balb/C mice (n= 128) via a subcapsular injection of a 0.1-cc suspension containing 10⁵ C-26 colon adenocarcinoma cells via a left flank incision at the initial procedure. Seven days later, the animals with isolated splenic tumors (95%) were randomized to one of two groups—open splenectomy (OS) or laparoscopic-assisted splenectomy (LAS). Three ports were placed in similar locations in all animals. The OS mice underwent an open splenectomy via a subcostal incision and anesthesia for 20 min. The LAS mice underwent laparoscopic mobilization of the spleen using a three-port technique, followed by an extracorporeal splenectomy via a subcostal incision. Seven days after splenectomy, the mice were killed and inspected for abdominal wall tumor implants. The experiment was carried out in four separate trials. Results: When the results of the four trials were combined, there was no significant difference in the incidence of animals with at least one port tumor recurrence between the OS vs the LAS group (25% vs 35.2%; p= 0.30, power = 0.91). However, the overall incidence of port site tumors (number of ports with tumors/total number of ports for each group) was significantly higher in the laparoscopic-assisted group than in the open group (18.5% vs 9.5%; p= 0.03). It was noted that the incidence of port tumor recurrence (PTR) in the LAS group dropped significantly from the first to the latter three trials (second, third, and fourth trials combined) (36.1% vs 13.5%; p < 0.006) while it did not change significantly in the OS group. In the latter three trials, there was no significant difference in the number of animals with PTR between the LAS and the OS group (13.5% vs 9.8%; p= 0.43). Conclusions: Overall, there was no significant difference between the OS and the LAS groups in number of animals with port tumor recurrence or subcostal wound tumor recurrence. However, there were more port tumors in the laparoscopic-assisted group. The reasons for these findings are unclear. The laparoscopic mobilization was quite difficult; it required excessive splenic manipulation, which may have liberated tumor cells from the primary lesion and facilitated port tumor formation. With increased experience, less manipulation was required to complete the mobilization. Of note, the incidence of port tumors in the LAS group decreased significantly from the first to the subsequent three trials; therefore, it is possible that surgical technique is a factor in port tumor formation. The CO₂ pneumoperitoneum may also be a factor, but this seems less likely. Received: 10 September 1999/Accepted: 4 April 2000/Online publication: 9 August 2000     

氩氦刀冷冻消融与射频消融在肝癌治疗中的临床应用

目的探讨氩氦刀冷冻消融与冷循环射频消融(cool-tip radiofrequency ablation,RFA)在恶性肝肿瘤治疗中的临床应用价值。方法超声引导下氩氦刀冷冻消融治疗肝癌38例共42个病灶;经超声引导下RFA治疗肝癌40例共44个病灶,治疗前后经超声造影、增强CT或增强MRI检查明确诊断及评价疗效。结果 42个病灶经一次冷冻消融治疗后32个达完全消融,10例经再次冷冻消融后达到完全消融;44个病灶经一次RFA治疗后完全消融33个,11例经再次RFA后达到完全消融。两者一次完全消融率分别为76.2%(冷冻消融)和75%(RFA),差异无统计学意义。结论氩氦刀冷冻消融和冷循环RFA均能有效地原位灭活肝癌细胞,是有效的非手术治疗恶性肝肿瘤的方法之一。     

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??Radiofrequency ablation applied in unresectable liver cancer in laparotomy XIE Dong-hui, CHEN Jian, CHANG Zhi-gang, et al. Department of Hepatobiliary and Pancreatic Surgery, Beijing Hospital, Beijing 100730??China Corresponding author: CHEN Jian, E-mail: chendaoxian@sina.com Abstract Objective To investigate the effect of radiofrequency ablation??RFA??in treating unresectable liver cancer in laparotomy. Methods RFA in laparotomy was applied in the patients suffered from unresectable liver cancer from May 2006 to November 2008 at Beijing Hospital. Twenty-six patients (46 lesions) were treated with RFA in laprotomy. During the same period, 17 patients ( 32 lesions) were in percutaneous RFA. Results All the patients were followed up with AFP, abdominal B-ultrasound and CT scans for 1 to 28 months, and the average time is 12.8 moths. Increasing of preoperative AFP occurred in 10 patients and recovered in 3 months after operation. Forty-five lesions were ablated completely ( 97.8%,45/46) , and 1 patient was suspected having residual lesion in CT scan. Two patients were died of postoperative bleeding. Three patients were found new lesions on liver in CT scan. Two patients were died of multi-metastasis during following up. Conclusion RFA applied in laprotomy is an effective and safe method in patients suffered from unresectable liver cancer.     

Bone Mineral Density of Opposing Hips Using Dual Energy X-Ray Absorptiometry in Single-Beam and Fan-Beam Design

Bone densitometry focuses on bone mineral area density (BMD in g/cm²) of the proximal femur and spine in anterior-posterior (AP) projections. Artifacts, such as osteoarthritis and osteophytic calcifications (OC) influence spine BMD, especially in AP scans. If only two sites are measured, as is usual in clinical practice, there may be advantages to measuring both femora rather than one femur and the spine. This would not be useful, however, if there was strong symmetry between the two sides. Furthermore, fan beam (FB) techniques have become available for measuring BMD with less data acquisition time. We compared densitometry of opposing femora in 421 patients (369 women, mean age 59.0 ± 4.8; 52 men, mean age 56.9 ± 7.4) using dual-energy X-ray absorptiometry (DXA): both single-beam (SB) and FB modes were evaluated. The precision errors in vivo (short- and midterm) of total BMD were 0.7% for both SB and FB. The total BMD and BMC of the left hip (0.817 ± 0.124 g/cm², 31.3 ± 6.4 g) were significantly (P < 0.001) higher (2–3%) than the corresponding values of the right hip (0.801 ± 0.125 g/cm², 30.3 ± 6.3 g) in both SB and FB (left BMD 0.802 ± 0.117 g/cm², BMC 30.0 ± 6.2 g versus right BMD 0.795 ± 0.117 g/cm², BMC 29.3 ± 6.3 g) modes. However, BMD of the femoral neck and Ward's triangle were not significantly (P > 0.05) different between the two sides. The FB results were generally 2% lower than SB results. There were highly significant (P < 0.001) correlations (r > 0.9) between both hips using both SB and FB. For diagnostic procedures and longitudinal studies, one should consider that there are bilateral differences of femur BMD, as well as differences between FB and SB scan modes.     

Production and systemic absorption of toxic byproducts of tissue combustion during laparoscopic surgery

Background: Among the potential hazards of laparoscopic surgery using electrocautery is the intraperitoneal release and subsequent absorption of byproducts of tissue combustion. In a porcine model of laparoscopic surgery with smoke production, our aims were to assess (1) the relationship between levels of intraperitoneal carbon monoxide (CO) and systemic carboxyhemoglobin (COHb) and methemoglobin (MetHb), and (2) intraperitoneal concentrations of other noxious gases, including hydrogen cyanide (HCN), acrylonitrile (Acr), and benzene (Bzn). Methods: Seven pigs underwent laparoscopic resection of three hepatic wedges using monopolar electrocautery in a CO₂ pneumoperitoneum. Sequential arterial samples were drawn to measure [COHb] and [MetHb] perioperatively, while gaseous intraabdominal [CO], [HCN], [Acr], and [Bzn] were assayed intraoperatively. Results: The mean ± SEM duration of operation was 90 ± 2 min, and electrocautery was used for 68 ± 4 min. Intraabdominal [CO] rose from 0 to 814 ± 200 ppm (p < 0.01) while [COHb] increased from 2.9 ± 0.1% to 3.5 ± 0.1% (p < 0.001). Systemic [MetHb] remained unchanged intra- and postoperatively, ranging from 0.3 to 0.7%. Intraperitoneal [HCN] rose from 0 to 5.7 ± 0.7 ppm (p < 0.001). [Acr], however, did not change significantly from preoperative values, ranging from 0 to 1.6 ± 1.0 ppm, and [Bzn] was undetectable. Conclusions: Laparoscopic tissue combustion increases intraabdominal [CO] to ``hazardous' levels leading to minimal, yet significant, elevations of [COHb]. Systemic [MetHb] and intraabdominal [HCN], [Acr], and [Bzn] are not elevated to toxic levels. Production of intraperitoneal smoke during laparoscopic electrosurgery therefore may not pose a significant threat to the patient. Received: 3 April 1997/Accepted: 22 May 1997