Impact of nationwide centralization of oesophageal, gastric, and pancreatic surgery on travel distance and experienced burden in the Netherlands.

BACKGROUND: This study aims to assess the impact of nationwide centralization of surgery on travel distance and travel burden among patients with oesophageal, gastric, and pancreatic cancer according to age in the Netherlands. As centralization of care increases to improve postoperative outcomes, travel distance and experienced burden might increase. MATERIALS AND METHODS: All patients who underwent surgery between 2006 and 2017 for oesophageal, gastric and pancreatic cancer in the Netherlands were included. Travel distance between patient's home address and hospital of surgery in kilometres was calculated. Questionnaires were used to assess experienced travel burden in a subpopulation (n = 239). Multivariable ordinal logistic regression models were constructed to identify predictors for longer travel distance. RESULTS: Over 23,838 patients were included, in whom median travel distance for surgical care increased for oesophageal cancer (n = 9217) from 18 to 28 km, for gastric cancer (n = 6743) from 9 to 26 km, and for pancreatic cancer (n = 7878) from 18 to 25 km (all p < 0.0001). Multivariable analyses showed an increase in travel distance for all cancer types over time. In general, patients experienced a physical and social burden, and higher financial costs, due to traveling extra kilometres. Patients aged >70 years travelled less often independently (56% versus 68%), as compared to patients aged ≤70 years. CONCLUSION: With nationwide centralization, travel distance increased for patients undergoing oesophageal, gastric, and pancreatic cancer surgery. Younger patients travelled longer distances and experienced a lower travel burden, as compared to elderly patients. Nevertheless, on a global scale, travel distances in the Netherlands remain limited.

Prognostic value of patient-reported quality of life for survival in oesophagogastric cancer: analysis from the population-based POCOP study.

BACKGROUND: Accumulating evidence of trials demonstrates that patient-reported health-related quality of life (HRQoL) at diagnosis is prognostic for overall survival (OS) in oesophagogastric cancer. However, real-world data are lacking. Moreover, differences in disease stages and tumour-specific symptoms are usually not taken into consideration. The aim of this population-based study was to assess the prognostic value of HRQoL, including tumour-specific scales, on OS in patients with potentially curable and advanced oesophagogastric cancer. METHODS: Data were derived from the Netherlands Cancer Registry and the patient reported outcome registry (POCOP). Patients included in POCOP between 2016 and 2018 were stratified for potentially curable (cT1-4aNallM0) or advanced (cT4b or cM1) disease. HRQoL was measured with the EORTC QLQ-C30 and the tumour-specific OG25 module. Cox proportional hazards models assessed the impact of HRQoL, sociodemographic and clinical factors (including treatment) on OS. RESULTS: In total, 924 patients were included. Median OS was 38.9 months in potentially curable patients (n = 795) and 10.6 months in patients with advanced disease (n = 129). Global Health Status was independently associated with OS in potentially curable patients (HR 0.89, 99%CI 0.82-0.97), together with several other HRQoL items: appetite loss, dysphagia, eating restrictions, odynophagia, and body image. In advanced disease, the Summary Score was the strongest independent prognostic factor (HR 0.75, 99%CI 0.59-0.94), followed by fatigue, pain, insomnia and role functioning. CONCLUSION: In a real-world setting, HRQoL was prognostic for OS in patients with potentially curable and advanced oesophagogastric cancer. Several HRQoL domains, including the Summary Score and several OG25 items, could be used to develop or update prognostic models.

Postoperative Complications and Long-Term Quality of Life After Multimodality Treatment for Esophageal Cancer: An Analysis of the Prospective Observational Cohort Study of Esophageal-Gastric Cancer Patients (POCOP).

BACKGROUND: Esophagectomy has major effects on health-related quality of life (HR-QoL). Postoperative complications might contribute to a decreased HR-QOL. This population-based study aimed to investigate the difference in HR-QoL between patients with and without complications after esophagectomy for cancer. METHODS: A prospective comparative cohort study was performed with data from the Netherlands Cancer Registry (NCR) and Prospective Observational Cohort Study of Esophageal-Gastric Cancer Patients (POCOP). All patients with esophageal and gastroesophageal junction (GEJ) cancer after esophagectomy in the period 2015-2018 were enrolled. The study investigated HR-QoL at baseline, then 3, 6, 9, 12, 18, and 24 months postoperatively, comparing patients with and without complications as well as with and without anastomotic leakage. RESULTS: The 486 enrolled patients comprised 270 patients with complications and 216 patients without complications. Significantly more patients with complications had comorbidities (69.6% vs 57.3%; p = 0.001). No significant difference in HR-QoL was found over time between the patients with and without complications. In both groups, a significant decline in short-term HR-QoL was found in various HR-QoL domains, which were restored to the baseline level during the 12-month follow-up period. No significant difference was found in HR-QoL between the patients with and without anastomotic leakage. The patients with grades 2 and 3 anastomotic leakage reported significantly more "choking when swallowing" at 6 months (ß = 14.5; 95% confidence interval [CI], - 24.833 to - 4.202; p = 0.049), 9 months (ß = 22.4, 95% CI, - 34.259 to - 10.591; p = 0.007), and 24 months (ß = 24.6; 95% CI, - 39.494 to - 9.727; p = 0.007) than the patients with grade 1 or no anastomotic leakage. CONCLUSION: In general, postoperative complications were not associated with decreased short- or long-term HR-QoL for patients after esophagectomy for esophageal or GEJ cancer. The temporary decrease in HR-QoL likely is related to the nature of esophagectomy and reconstruction itself.

Recurrent incisional hernia repair: surgical outcomes in correlation with body-mass index.

BACKGROUND: Hernia recurrence rates after incisional hernia repair vary between 8.7 and 32%, depending on multiple factors such as patient characteristics, the use of meshes, surgical technique and the degree of experience of the treating surgeon. Recurrent hernias are considered complex wall hernias, and 20% of all incisional hernia repairs involve a recurrent hernia. The aim of this study was to investigate the outcomes after recurrent incisional hernia repair, in association with surgical technique and body-mass index (BMI). METHODS: All patients who had incisional hernia repair between 2013 and 2018 were included. Primary outcome was rate of recurrent incisional hernia after initial hernia repair. Secondary outcomes were complication rate and recurrence rate in association with BMI. RESULTS: A number of 269 patients were included, of which 75 patients (27.9%) with a recurrent incisional hernia. Recurrent hernia repair was performed in 49 patients, 83.7% underwent open repair. Complication rate for recurrent hernia repair was higher than for the initial incisional hernia repair. Of the 49 patients with recurrent hernia repair, patients with a BMI above 30 had higher complication and recurrence rates compared to patients with BMI below 30. Especially infectious complications were more common in patients with a higher BMI: 23.1% vs. 0% wound infections. CONCLUSION: The results from this study show that complication and recurrence rates are increased after recurrent incisional hernia repair, which are further increased by obesity. Only a limited amount of literature is available on this topic, further larger multicenter studies are necessary, until then a patient-specific surgical approach based on the surgeon's expertise is recommended.

Implementation of the small bites closure of abdominal midline incisions in clinical practice is correlated with a reduction in surgical site infections.

BACKGROUND: Small steps wound closure of midline laparotomy has been reported to decrease the incidence of incisional hernia development in two randomized controlled trials. The aim of the present study was to evaluate the effect of implementing the small steps wound closure technique in clinical practice with regards to the development of incisional ventral hernia (IVH) and surgical site infections (SSI) in clinical practice. METHODS: Implementation of the small steps wound closure technique using the small tissue bites technique as the standard closure technique for abdominal midline incisions in our clinical practice was done in March 2015. For this study, all patients from June 2013 until June 2016 with a midline laparotomy, either long or small in case of specimen extraction in laparoscopic surgery, in either elective or emergency setting were included. Conventional large bite wound closure was compared to small steps wound closure with regards to the development of SSI, IVH as well as burst abdomen. RESULTS: A total of 327 patients were included. The small steps suture technique was used in 136 (42%) of the patients, whereas the conventional large bites suture technique was used in 191 patients (58%). A total of 54 patients in the large bites group developed SSI (28%) compared to 23 (17%) patients in the small steps group (p = 0.02). A total number of 10 patients (7%) developed IVH in the small steps group compared to 27 patients (14%) in the large bites group (p = 0.08). CONCLUSION: Implementation of small bites wound closure of abdominal midline incisions in clinical practice was correlated with a reduction in surgical site infections.

Quality of Life During and After Completion of Neoadjuvant Chemoradiotherapy for Esophageal and Junctional Cancer.

BACKGROUND: The course of health-related quality of life (HRQOL) during and after completion of neoadjuvant chemoradiotherapy (nCRT) for esophageal or junctional carcinoma is unknown. METHODS: This study was a multicenter prospective cohort investigation. Patients with esophageal or cancer to be treated with nCRT plus esophagectomy were eligible for inclusion in the study. The HRQOL of the patients was measured with European Organization for Research and Treatment of Cancer QLQ-C30, QLQ-OG25, and QLQ-CIPN20 questionnaires before and during nCRT, then 2, 4, 6, 8, 10, 12, 14, and 16 weeks after nCRT and before surgery. Predefined end points were based on the hypothesized impact of nCRT. The primary end points were physical functioning, odynophagia, and sensory symptoms. The secondary end points were global quality of life, fatigue, weight loss, and motor symptoms. Mixed modeling analysis was used to evaluate changes over time. RESULTS: Of 106 eligible patients, 96 (91%) were included in the study. The rate of questionnaires returned ranged from 94% to 99% until week 12, then dropped to 78% in week 16 after nCRT. A negative impact of nCRT on all HRQOL end points was observed during the last cycle of nCRT (all p < 0.001) and 2 weeks after nCRT (all p < 0.001). Physical functioning, odynophagia, and sensory symptoms were restored to pretreatment levels respectively 8, 4, and 6 weeks after nCRT. The secondary end points were restored to baseline levels 4-6 weeks after nCRT. Odynophagia, fatigue, and weight loss improved after nCRT compared with baseline levels at respectively 6 (p < 0.001), 16 (p = 0.001), and 12 weeks (p < 0.001). CONCLUSION: After completion of nCRT for esophageal cancer, HRQOL decreases significantly, but all HRQOL end points are restored to baseline levels within 8 weeks. Odynophagia, fatigue, and weight loss improved 6-16 weeks after nCRT compared with baseline levels.

Overall survival before and after centralization of gastric cancer surgery in the Netherlands.

BACKGROUND: Centralization of surgery has been shown to improve outcomes for oesophageal and pancreatic cancer, and has been implemented for gastric cancer since 2012 in the Netherlands. This study evaluated the impact of centralizing gastric cancer surgery on outcomes for all patients with gastric cancer. METHODS: Patients diagnosed with non-cardia gastric adenocarcinoma in the intervals 2009-2011 and 2013-2015 were selected from the Netherlands Cancer Registry. Clinicopathological data, treatment characteristics and mortality were assessed for the periods before (2009-2011) and after (2013-2015) centralization. Cox regression analyses were used to assess differences in overall survival between these intervals. RESULTS: A total of 7204 patients were included. Resection rates increased slightly from 37·6 per cent before to 39·6 per cent after centralization (P = 0·023). Before centralization, 50·1 per cent of surgically treated patients underwent gastrectomy in hospitals that performed fewer than ten procedures annually, compared with 9·2 per cent after centralization. Patients who had gastrectomy in the second interval were younger and more often underwent total gastrectomy (29·3 per cent before versus 41·2 per cent after centralization). Thirty-day postoperative mortality rates dropped from 6·5 to 4·1 per cent (P = 0·004), and 90-day mortality rates decreased from 10·6 to 7·2 per cent (P = 0·002). Two-year overall survival rates increased from 55·4 to 58·5 per cent among patients who had gastrectomy (P = 0·031) and from 27·1 to 29·6 per cent for all patients (P = 0·003). Improvements remained after adjustment for case mix; however, adjustment for hospital volume attenuated this association for surgically treated patients. CONCLUSION: Centralization of gastric cancer surgery was associated with reduced postoperative mortality and improved survival.

Evaluation of PET and laparoscopy in STagIng advanced gastric cancer: a multicenter prospective study (PLASTIC-study).

BACKGROUND: Initial staging of gastric cancer consists of computed tomography (CT) and gastroscopy. In locally advanced (cT3-4) gastric cancer, fluorodeoxyglucose positron emission tomography with CT (FDG-PET/CT or PET) and staging laparoscopy (SL) may have a role in staging, but evidence is scarce. The aim of this study is to evaluate the impact and cost-effectiveness of PET and SL in addition to initial staging in patients with locally advanced gastric cancer. METHODS: This prospective observational cohort study will include all patients with a surgically resectable, advanced gastric adenocarcinoma (cT3-4b, N0-3, M0), that are scheduled for treatment with curative intent after initial staging with gastroscopy and CT. The modalities to be investigated in this study is the addition of PET and SL. The primary outcome of this study is the proportion of patients in whom the PET or SL lead to a change in treatment strategy. Secondary outcome parameters are: diagnostic performance, morbidity and mortality, quality of life, and cost-effectiveness of these additional diagnostic modalities. The study recently started in August 2017 with a duration of 36 months. At least 239 patients need to be included in this study to demonstrate that the diagnostic modalities are break-even. Based on the annual number of gastrectomies in the participating centers, it is estimated that approximately 543 patients are included in this study. DISCUSSION: In this study, it is hypothesized that performing PET and SL for locally advanced gastric adenocarcinomas results in a change of treatment strategy in 27% of patients and an annual cost-reduction in the Netherlands of €916.438 in this patient group by reducing futile treatment. The results of this study may be applicable to all countries with comparable treatment algorithms and health care systems. TRIAL REGISTRATION: NCT03208621 . This trial was registered prospectively on June 30, 2017.

Outcomes of surgery on patients with a clinically inapparent inguinal hernia as diagnosed by ultrasonography.

BACKGROUND: Chronic post-operative inguinal pain (CPIP) is the most significant complication following inguinal hernia repair. Patients without a palpable hernia prior to surgery seemed to report more CPIP. Our aim was to evaluate the effects of surgery on patients with a clinically inapparent inguinal hernia as diagnosed using ultrasonography. METHODS: A total of 179 hernia repairs in patients with a positive ultrasonography but negative physical examination were analysed retrospectively. Patients with recurrent hernias, femoral hernias or previous surgery to the inguinal canal were excluded. The primary outcome was the presence of chronic postoperative inguinal pain (pain > 3 months postoperatively). Data on preoperative complaints, surgical technique and findings during ultrasonography and surgery were also studied in relation to the development of CPIP. RESULTS: A quarter (25.1%) of the patients reported chronic postoperative pain. Female gender (p = 0.03), high BMI (p = 0.04) and atypical symptoms prior to surgery (p < 0.001) were significant univariate risk factors for developing CPIP. Logistic regression showed a significant association between atypical symptoms and CPIP [OR = 6.31, p < 0.001, 95% CI (2.32, 17.16)], which was still present after correction for the significant univariate variables [OR = 4.23, p = 0.02, 95% CI (1.26, 14.21)]. CONCLUSION: Patients with a clinically inapparent inguinal hernia as diagnosed using ultrasonography report a high incidence of CPIP after elective hernia repair. Patients with atypical groin pain prior to surgery are especially prone to CPIP. It is questionable whether these hernias should be classified and treated as symptomatic inguinal hernias. The results advocate taking other causes of groin pain into consideration before choosing surgical treatment.

Improved quality of care for patients undergoing an abdominoperineal excision for rectal cancer.

INTRODUCTION: New diagnostics, the emergence of total mesorectal excision and neoadjuvant treatments have improved outcome for patients with rectal cancer. Patients with distal rectal cancer undergoing an abdominoperineal excision seem to do worse compared to those treated with sphinctersparing techniques. The aim of this study was to evaluate the quality of care for patients undergoing an abdominoperineal excision for distal rectal cancer during the last 15 years. MATERIALS AND METHODS: All patients with rectal cancer, who underwent an abdominoperineal excision between December 1996 and December 2010 in 5 Dutch hospitals were analysed. Patients were divided into three cohorts; 1996-2001, 2001-2005 and 2006-2010. All data was extracted from medical records. RESULTS: 477 patients were identified. There was no significant difference in sex, age, BMI, prior pelvic surgery and ASA stages between the cohorts. MRI became a standard tool in the work-up, the use increased from 4.5% in the first, to 95.1% in the last cohort (p < 0.0001). Neoadjuvant treatment shifted from predominantly none (64.9% in cohort 1) to short course radiotherapy (66.7% in cohort 2) and chemoradiation therapy (55.7% in cohort 3). There was a trend towards a decreased circumferential resection margin involvement in the cohorts (18.8%, 16.7% and 11.4%; p = 0.142). Accidental bowel perforations have significantly decreased from 28.6%, and 21.7% to 9.2% in cohort 3 (p < 0.0001). CONCLUSION: Significant improvements in work-up, neoadjuvant and surgical treatment have been made for patients with low rectal cancer, undergoing an abdominoperineal excision. These improvements result in improved short term outcome.

Totally extraperitoneal repair for bilateral inguinal hernia: does mesh configuration matter?

BACKGROUND: The endoscopic preperitoneal approach has numerous advantages for the reconstruction of bilateral inguinal hernias. Repair may be achieved using either one large or two small meshes. The aim of this study was to investigate whether one of the techniques was superior in terms of recurrence and complication rate. METHODS: Data obtained from 113 patients who underwent surgery between January 1998 and December 2001 was reviewed. For the sake of this study, 86% of all patients were examined for hernia recurrence at an additional outpatient visit. RESULTS: The findings showed recurrence rates, of 3.5% for single mesh and 3.7% for double mesh. This difference was not significant. Complication rates did not differ significantly between the groups. CONCLUSIONS: Endoscopic preperitoneal bilateral hernia repair is a safe and reliable technique in the hands of experienced surgeons. The rate of hernia recurrence and complications is low and independent of the mesh configuration (single or double). Mesh configuration based on personal preference is permissible.

Long-term follow-up after umbilical hernia repair: are there risk factors for recurrence after simple and mesh repair.

Adult umbilical hernia is a common surgical condition mainly encountered in the fifth and sixth decade of life. Despite the high frequency of the umbilical hernia repair procedure, disappointingly high recurrence rates, up to 54% for simple suture repair, are reported. Since both mesh and suture techniques are used in our clinic we set out to investigate the respective recurrence rates and associated complications, retrospectively. Patients who were treated between January 1998 and December 2002 were identified from our hospital database and invited to attend the outpatient department for an extra follow-up, history taking and physical examination. The use of prosthetic material, occurrence of surgical site infection, body mass and height as well as recurrence were recorded at the time of this survey. In total, 131 consecutive patients underwent operative repair of an umbilical hernia. Twenty-eight percent of the patients were female (n = 37). In 12 patients (11%) umbilical hernia repair was achieved with mesh implantation. Fourteen umbilical hernia recurrences were noted (13%); none had been repaired using mesh. No relationship was found between wound infection or obesity and umbilical hernia recurrence. In the light of these results it is necessary to re-evaluate our clinical "guidelines" on mesh placement in umbilical hernia repair: apparently not every umbilical fascial defect needs mesh repair. Research should focus on establishing risk factors for hernia recurrence.

Long-term results after modified Gallie technique for incisional hernia repair: results in 19 patients.

BACKGROUND: A modified forgotten technique for repairing large incisional hernias is described together with its long-term results in 19 patients. A synthetic mesh with 1-cm wide spokes radiating from the mesh is placed preperitioneally, overlapping the fascial defect. The spokes are pulled through rectus sheaths and muscle and sutured ventrally, thereby creating a solid reconstruction withstanding shrinking of the mesh. METHOD: Nineteen patients were operated on (13 primary incisional hernia, minimal fascial defect 10 cm). Notes on patients were reviewed, and the patients were contacted for follow-up examination. RESULTS: No major complications occurred. After a median of 49 months, 17 patients were reviewed at the outpatient clinic. Two possible recurrences were detected, of which one was operated on. This proved to be bulging of the mesh, resulting in a recurrence of 1 out of 17 (6%). CONCLUSION: From these results, it is concluded that Gallie's technique using synthetic mesh is a safe and effective repair for incisional hernia and deserves more attention, especially for large fascial defects.

Interstitial laser coagulation with temporary hepatic artery occlusion for patients with cirrhosis and irresectable hepatoma.

BACKGROUND: The aim was to determine the degree of local control of hepatocellular carcinoma (HCC) in patients with cirrhotic liver disease when treated with ultrasonographically guided interstitial laser coagulation (ILC) with temporary hepatic artery occlusion. METHODS: Sixteen patients with 24 HCC tumours were treated. Follow-up was by computed tomography or magnetic resonance imaging every 3 months. RESULTS: Nineteen of 24 tumours showed complete necrosis immediately after treatment, and there was no tumour recurrence during follow-up (mean 14 months, median 12 months). No effect on liver function was observed after 1 week and there was no death. In 13 of the 16 patients, new HCC foci developed at other sites. CONCLUSION: Percutaneous ILC combined with temporary hepatic artery occlusion during a single session is an effective local treatment for HCC nodules smaller than 5 cm. However, new HCC lesions develop in the majority of patients, which underscores the need for adjuvant therapy or repeated treatment in these patients.

Metabolic activity and DNA integrity in human hepatic metastases after interstitial laser coagulation (ILC).

BACKGROUND AND OBJECTIVE: For investigations into interstitial laser coagulation (ILC) of solid tumors, tissue whitening is used as a parameter for the extent of coagulation. This obvious demarcation is associated with global thermal denaturation, but it is not clear whether this finding is a good indicator of the exact outer boundary of the lethal tissue effect. STUDY DESIGN/MATERIALS AND METHODS: ILC with portal inflow occlusion was performed in human hepatic metastases of colorectal carcinoma directly after surgical resection (n = 5) or before surgical resection (n = 5) with laser parameters adapted to tumor diameter. Mitochondrial NADH-diaphorase activity and DNA integrity were assessed by histoenzymatic staining. RESULTS: In 7 of 10 tumors (mean diameter, 3.7 cm), an area of macroscopic coagulation (mean diameter, 4.2 cm) encircled the tumor in all three axes. Macroscopic coagulation corresponded to absent metabolism and disintegrated DNA. Furthermore, the macroscopic volumes of coagulation produced in tumor were comparable to the dimensions in normal porcine liver with the same laser parameters. CONCLUSION: ILC with portal inflow occlusion results in areas with complete cell avitality in the zone of tissue whitening in human hepatic liver metastases.

[Treatment of non-resectable liver tumors with percutaneous interstitial laser coagulation while interrupting blood circulation to the liver]. / Behandeling van patiënten met irresectable tumoren in de lever door middel van percutane interstitiële lasercoagulatie tijdens onderbreking van de bloedstroom naar de lever.

OBJECTIVE: To evaluate, in patients with hepatocellular carcinoma or colorectal carcinoma disseminated to the liver, treatment with interstitial laser coagulation (ILC) during temporary occlusion of vascular inflow in the liver: feasibility, complications and initial tumour response. DESIGN: Prospective, descriptive. METHODS: Patients were included if their tumours were surgically irresectable and smaller than 4 cm in diameter and did not exceed a number of 3. ILC was performed under general anaesthesia, basically via a percutaneous approach. Vascular inflow was occluded during laser treatment. Twenty-four hours after ILC a triphasic spiral CT was performed to assess the result of the treatment. RESULTS: In 10 patients 14 hepatic tumours were lasered in 12 treatment sessions (10 percutaneous and 2 at laparotomy). After 5 treatment sessions, complications were observed of which pain at the insertion site of the catheters was the most frequent. For 6 out of the 10 patients with percutaneous procedures, discharge was within 24 hours after ILC. Nine out of the 14 tumours (65%) were completely coagulated. CONCLUSION: ILC with vascular inflow occlusion is a safe and feasible technique that can be performed during a short hospital stay. Initial tumour response is 65% and these results justify determination of duration of response in a larger group of patients.

Critical temperature and heating time for coagulation damage: implications for interstitial laser coagulation (ILC) of tumors.

BACKGROUND: Interstitial laser coagulation (ILC) is a method of local tissue destruction for solid tumors such as irresectable hepatic metastases from colorectal cancer. With the availability of new magnetic resonance (MR) techniques, which allow real time tissue temperature mapping, it is essential to know the critical temperature and exposure times leading to cell death. MATERIALS AND METHODS/STUDY DESIGN: Samples (8 mm(3)) of solid rat tumor (CC-531, syngenic to the WAG/Rij rat strain), were warmed in tubes for four different temperatures (40, 50, 60 or 80 degrees C) and four different exposure times (3, 6, 12, or 24 minutes). Combinations were replicated in five-fold. Cell viability was assessed with three methods: Trypan blue exclusion test in collagenase/dispase dissociated samples, NADH activity in snap frozen samples and outgrowth for 2 weeks under the renal capsule of WAG/Rij rats. RESULTS: Results of the three methods revealed that viability was not affected with heating at 40 and 50 degrees C except for 24 minutes at 50 degrees C. At higher temperatures cell death occurred at all exposure times. CONCLUSION: The temperature range resulting in sufficient tissue coagulation for cell death is between 50 degrees C and 60 degrees C for a short duration (<3 minutes). These data can be used to achieve complete tumor destruction and minimal surrounding tissue damage during real-time MR-controlled ILC.

Long-term effects of interstitial laser coagulation in porcine liver with portal inflow occlusion: central versus peripheral lesions.

PURPOSE: Interstitial laser coagulation (ILC) is an attractive modality for local destruction of unresectable hepatic metastases. Portal inflow occlusion considerably increases its destructive capacity, resulting in lesions 5 cm in diameter; however, effects on adjoining major intrahepatic structures are unknown. Therefore, the purpose of this study was to assess the effects of ILC with portal inflow occlusion on the central portion of the liver as compared to the peripheral portions. MATERIALS AND METHODS: ILC was performed in pigs with portal inflow occlusion. Each animal received a single laser application with Nd:YAG light guided simultaneously through four interstitial fibers with 5 W per fiber during 6 minutes. Location of treatment was randomized to either central (n = 8) or peripheral (n = 8). Follow-up was for 1, 2, or 3 months with evaluation of liver functions and weight, as well as macroscopic and microscopic assessment of coagulated lesions and surrounding parenchyma. RESULTS: There was no treatment-related morbidity or mortality. No obstructive cholestasis or bile leakage was found. At every moment of evaluation, coagulated volumes in the central group were smaller than in the peripheral lesions (P = .03). Large vessels contiguous to the lesions in the central group were always intact and indications of portal hypertension or thrombosis of hepatic veins were not found. There were no significant differences between the two groups (liver functions [P > or = .15] and weight [P = .69]). CONCLUSION: ILC with portal inflow occlusion is a safe technique in the vicinity of vital structures in the liver of healthy pigs. These results justify studies to the feasibility and complication rate of portal inflow occlusion in patients with hepatic malignancies.

Accuracy of MR phase mapping for temperature monitoring during interstitial laser coagulation (ILC) in the liver at rest and simulated respiration.

The chemical shift or proton-resonance frequency (phase mapping) can be used to measure temperature changes. As a subtraction technique, it requires scans at exactly the same location, making it prone to respiration-induced artifacts. The accuracy of magnetic resonance (MR) phase mapping for temperature monitoring of interstitial laser coagulation (ILC) was therefore investigated in two ex vivo models with simulated respiration. MR temperatures were calibrated to interstitially measured temperature. Gradual cooling of a homogenous medium (gel) was monitored for four starting temperatures (room temperature, 40 degrees C, 50 degrees C, and 60 degrees C) during 30 min. Temperature increases were measured during ILC in ex vivo porcine liver with Nd:YAG for 6 min with 5 Watt. Experiments were performed at rest and with simulated respiratory motion (both n = 5). In liver, accuracy did not decrease with respiration simulation (P = 0.32), whereas a significant decline was found in the gel model (P = 0.002). In all experiments a small drift over time was observed between temperature determined with MR and thermoprobes. Correction for temperature-independent phase-shift at a reference location did not enhance agreement. Temperatures could be determined correctly by MR in the moving liver within a range of +/-3.5 degrees C after 6 min of laser application (95% confidence interval), justifying further pre-clinical studies.