Measurement of physical activity in clinical practice using accelerometers

Accelerometers are commonly used in clinical and epidemiological research for more detailed measures of physical activity and to target the limitations of self-report methods. Sensors are attached at the hip, wrist and thigh, and the acceleration data are processed and calibrated in different ways to determine activity intensity, body position and/or activity type. Simple linear modelling can be used to assess activity intensity from hip and thigh data, whilst more advanced machine-learning modelling is to prefer for the wrist. The thigh position is most optimal to assess body position and activity type using machine-learning modelling. Frequency filtering and measurement resolution needs to be considered for correct assessment of activity intensity. Simple physical activity measures and statistical methods are mostly used to investigate relationship with health, but do not take advantage of all information provided by accelerometers and do not consider all components of the physical activity behaviour and their interrelationships. More advanced statistical methods are suggested that analyse patterns of multiple measures of physical activity to demonstrate stronger and more specific relationships with health. However, evaluations of accelerometer methods show considerable measurement errors, especially at individual level, which interferes with their use in clinical research and practice. Therefore, better objective methods are needed with improved data processing and calibration techniques, exploring both simple linear and machine-learning alternatives. Development and implementation of accelerometer methods into clinical research and practice requires interdisciplinary collaboration to cover all aspects contributing to useful and accurate measures of physical activity behaviours related to health.

Platelet Adhesion in Polytetrafluoroethylene (PTFE) Vascular Grafts In Vivo and the Influence of Increased Intramuscular Pressure-An Experimental Model

Thrombogenicity of graft material is involved in early graft failure in small diameter grafts. The frequently seen postoperative swelling of the leg after distal revascularization may cause an increased intramuscular pressure and early graft failure.

Pairs of 4 mm polytetrafluoroethylene (PTFE) grafts were implanted. Autologous platelets were labeled with mIn-oxine. Platelet adhesiveness onto the grafts were analyzed from gamma camera images. Intramuscular pressures were measured with wick technique. Blood flow was measured. One graft served as control the other as test graft. Ninety minutes after declamping the i. m. pressure was increased in the test-leg to 30 mmHg, and later to 60 mmHg.

In the control-graft platelet uptake increased to a maximum 60 min after declamping. Blood flow and i.m. pressure remained uneffected. The test-grafts were initially similar but when i.m. pressure was increased to 30 mmHg activity in the grafts increased significantly. Blood flow decreased with 12% of initial flow. When i. m. pressure was raised to 60 mmHg platelet uptake continued to increase.

An increased intramuscular pressure of 30 mmHg or more significantly increase the amount of platelets adhering onto PTFE grafts, emphasizing the need for measuring intramuscular pressures after lower limb vascular revascularizations.

Validation of SenseWear Armband in children, adolescents, and adults

SenseWear Armband (SW) is a multisensor monitor to assess physical activity and energy expenditure. Its prediction algorithms have been updated periodically. The aim was to validate SW in children, adolescents, and adults. The most recent SW algorithm 5.2 (SW5.2) and the previous version 2.2 (SW2.2) were evaluated for estimation of energy expenditure during semi-structured activities in 35 children, 31 adolescents, and 36 adults with indirect calorimetry as reference. Energy expenditure estimated from waist-worn ActiGraph GT3X+ data (AG) was used for comparison. Improvements in measurement errors were demonstrated with SW5.2 compared to SW2.2, especially in children and for biking. The overall mean absolute percent error with SW5.2 was 24% in children, 23% in adolescents, and 20% in adults. The error was larger for sitting and standing (23%-32%) and for basketball and biking (19%-35%), compared to walking and running (8%-20%). The overall mean absolute error with AG was 28% in children, 22% in adolescents, and 28% in adults. The absolute percent error for biking was 32%-74% with AG. In general, SW and AG underestimated energy expenditure. However, both methods demonstrated a proportional bias, with increasing underestimation for increasing energy expenditure level, in addition to the large individual error. SW provides measures of energy expenditure level with similar accuracy in children, adolescents, and adults with the improvements in the updated algorithms. Although SW captures biking better than AG, these methods share remaining measurements errors requiring further improvements for accurate measures of physical activity and energy expenditure in clinical and epidemiological research.

Ultrasound Monitored Laser-Induced Local Hyperthermia in the Liver

Ultrasound (US) was used to monitor the size of tissue necrosis generated by Nd-YAG laser-induced local interstitial hyperthermia and tissue coagulation in 8 normal pig livers. Four treatments were done in each liver with 4 different energy settings. The size of the tissue necrosis measured on specimens was compared to the size measured on US. The laser energy caused a round tissue necrosis with some charring in the centre surrounded by a zone of white necrosis and a thin border of hyperaemia. A good correlation was found between the true and US-measured size of the necrosis diameters. It therefore seems possible to safely guide and monitor local laser hyperthermia in the liver with real-time US. The water-cooled quartz fibre used in this study has, however, some limitations.

High-frequency jet ventilation shortened the duration of gas embolization during laparoscopic liver resection in a porcine model

BACKGROUND

Positive pressure mechanical ventilation causes rhythmic changes in thoracic pressure and central blood flow. If entrainment occurs, it could be easier for carbon dioxide to enter through a wounded vein during laparoscopic liver lobe resection (LLR). High-frequency jet ventilation (HFJV) is a ventilating method that does not cause pronounced pressure or blood flow changes. This study aimed to investigate whether HFJV could influence the frequency, severity, or duration of gas embolism (GE) during LLR.

METHODS

Twenty-four anaesthetized piglets underwent lobe resection and were randomly assigned to either normal frequency ventilation (NFV) or HFJV (n=12 per group). During resection, a standardized injury to the left hepatic vein was created to increase the risk of GE. Haemodynamic and respiratory variables were monitored. Online blood gas monitoring and transoesophageal echocardiography were used. GE occurrence and severity were graded as 0 (none), 1 (minor), or 2 (major), depending on the echocardiography results.

RESULTS

GE duration was shorter in the HFJV group (P=0.008). However, no differences were found between the two groups in the frequency or severity of embolism. Incidence of Grade 2 embolism was less than that found in previous studies and physiological responses to embolism were variable.

CONCLUSION

HFJV shortened the mean duration of GE during LLR and was a feasible ventilation method during the procedure. Individual physiological responses to GE were unpredictable.

Elevated PEEP without effect upon gas embolism frequency or severity in experimental laparoscopic liver resection

BACKGROUND

Carbon dioxide (CO(2)) embolism is a potential complication in laparoscopic liver surgery. Gas embolism (GE) is thought to occur when central venous pressure (CVP) is lower than the intra-abdominal pressure (IAP). This study aimed to investigate whether an increased CVP due to induction of PEEP could influence the frequency and severity of GE during laparoscopic liver resection.

METHODS

Twenty anaesthetized piglets underwent laparoscopic left liver lobe resection and were randomly assigned to either 5 or 15 cm H(2)O PEEP (n=10 per group). During resection, a standardized injury to the left hepatic vein [venous cut (VC)] was created to increase the risk of GE. Haemodynamic and respiratory variables were monitored, and online arterial blood gas monitoring and transoesophageal echocardiography (TOE) were used. The occurrence and severity of embolism was graded as 0 (none), 1 (minor), or 2 (major), depending on the TOE results.

RESULTS

No differences were found between the two groups regarding the frequency or severity of GE, during either the VC (P=0.65) or the rest of the surgery (P=0.24). GE occurred irrespective of the CVP-IAP gradient.

CONCLUSIONS

Mechanisms other than the CVP-IAP gradient seemed during laparoscopic liver surgery to contribute to the formation of CO(2) embolism. This is of clinical importance to the anaesthetists.

High intra-abdominal pressure during experimental laparoscopic liver resection reduces bleeding but increases the risk of gas embolism

BACKGROUND

Various recommendations exist regarding intra-abdominal pressure (IAP) during laparoscopic liver resection. A high IAP may reduce bleeding but at the same time increase the risk of gas embolism. This study investigated the effects of two different IAPs during laparoscopic left liver lobe resection in piglets.

METHODS

Sixteen piglets underwent laparoscopic left liver lobe resection using carbon dioxide pneumoperitoneum of either 8 or 16 mmHg (8 per group). A combination of CUSA System 200™ and LigaSure™ instruments was used for parenchymal division. During resection, a standard injury to the left liver vein was also created to increase the risk of bleeding and/or gas embolism during the operation. Heart rate, cardiac output, and arterial, pulmonary arterial, pulmonary capillary wedge and central venous pressures were measured. Arterial blood gases were monitored continuously. Transoesophageal echocardiography was video recorded to detect and quantify gas embolism within the right cardiac ventricle. The duration of operation and bleeding were noted.

RESULTS

High IAP resulted in reduced bleeding (P = 0·016), but gas embolism occurred more frequently (P = 0·001) than with low IAP. Gas embolism disturbed gas exchange, with an increase in arterial pressure of carbon dioxide, and a decrease in arterial partial pressure of oxygen and pH. These effects were sustained for at least 30 min after surgery.

CONCLUSION

High IAP reduces the amount of bleeding but increases the risk of gas embolism. Monitoring for gas embolism is therefore indicated if a high IAP is used during laparoscopic liver resection.

Gas embolism during laparoscopic liver resection in a pig model: frequency and severity

BACKGROUND

Laparoscopic liver surgery is evolving rapidly. Carbon dioxide embolism is a potential complication. The aim of this work was to study the frequency and severity of gas embolism (GE) during laparoscopic liver lobe resection in a pig model and the resulting cardiovascular and respiratory changes.

METHODS

Fifteen anaesthetized piglets underwent laparoscopic left liver lobe resection. Haemodynamic and respiratory variables were monitored, including systemic and pulmonary arterial pressures, end-tidal CO2, and pulmonary dead space. Online blood gas monitoring and a transoesophageal echocardiography (TOE) were used. GE was graded semi-quantitatively as grade 0 (none), grade 1 (minor), or grade 2 (major), depending on the TOE results.

RESULTS

In 10 of 15 piglets, GE occurred. In total, 33 separate episodes of GE were recorded. All 13 episodes of grade 2 and three of grade 1 were serious enough to cause mainly respiratory, but also haemodynamic effects. Mostly, grade 1 GE caused only minor respiratory or haemodynamic changes. Most variables were affected during grade 2 GE; the most important were Pa(o(2)), Pa(co(2)), end-tidal CO2, Vd/Vt, and mean pulmonary arterial pressure.

CONCLUSIONS

GE occurred frequently during laparoscopic liver resection in this experimental study. Approximately half of the embolisms were serious enough to cause respiratory or haemodynamic disturbances or both. Pending further human studies, a combination of several monitoring techniques, with narrow limits for the alarm settings, will ensure correct interpretation of the complex physiological response to GE and reveal it early enough to alert the anaesthetist and the surgeon to the ongoing problem.

Physical activity, sports participation and aerobic fitness in children who have undergone surgery for congenital heart defects

AIM

To investigate physical activity, sports participation and aerobic fitness in children who have undergone surgery for congenital heart defects.

SUBJECTS AND METHODS

Children who had undergone surgery for congenital heart defects and healthy controls in the Gothenburg area were invited to participate in the study. All participants were aged 9-11 or 14-16 years. The activity monitor ActiReg was used to assess physical activity. Participants were interviewed about their participation in sports and performed a maximal exercise test on a bicycle with measured oxygen uptake.

RESULTS

A total of 32 and 25 patients, and 61 and 45 controls, in the two age-groups were included, respectively. The patients had a wide range of severity of congenital heart defects. The physical activity level was similar in the patients and the controls. The rate of sports participation was high for both patients and controls; 80-94% of all participants took part in sports at least once a week. The majority of the patients were considered to have at least a moderate level of aerobic fitness.

CONCLUSIONS

Although children who have undergone surgery for congenital heart defects have a similar level of physical activity compared with that of healthy children, some of them may require support to participate in exercise and vigorous physical activity.

Discomfort five years after laparoscopic and Shouldice inguinal hernia repair: a randomised trial with 867 patients. A report from the SMIL study group

BACKGROUND

In recent years long-term discomfort after inguinal hernia surgery has become an issue of great concern to hernia surgeons. Long-term results on discomfort from large randomised studies are sparse.

METHODS

One-thousand one-hundred and eighty-three patients were randomised in a multicentre trial with the primary aim of comparing recurrence rates after laparoscopic TAPP and Shouldice repair. Evaluating late discomfort and its possible risk factors were secondary objectives, and are reported here. The patients were clinically examined after 1 and 5 years, and answered questionnaires 2 and 3 years postoperation.

RESULTS

Of 1,068 operated patients, 867 were eligible for analysis after 5 years (81.2%). The percentage of patients experiencing discomfort of any kind were 8.5% in the TAPP group and 11.4% (p = 0.156) in the Shouldice group. Although discomfort was usually mild it was severe for 0.2 and 0.7%, respectively. Severe pain the first postoperative week was a risk factor for late discomfort in the Shouldice group (OR 2.25, P = 0.022) but not in the TAPP group. No other risk factor for late discomfort was found.

CONCLUSION

There was no difference between late discomfort at five-year follow-up after laparoscopic TAPP and Shouldice repair. Discomfort was mostly mild and pain during the first postoperative week was a prognostic variable for late discomfort in Shouldice patients.

Laparoscopic parenchymal division of the liver in a porcine model: comparison of the efficacy and safety of three different techniques

BACKGROUND

Bleeding is a known and CO2 embolization a suggested risk factor for increased morbidity after laparoscopic liver resection. Devices for laparoscopic liver parenchymal transection must be evaluated for safety in this context.

METHOD

Twelve piglets underwent laparoscopic surgery during CO2 pneumoperitoneum, each animal receiving three 6 cm long transections into the liver parenchyma made with ultrasonic dissector, ultrasonic shears and vessel sealing system, respectively. Endpoints were bleeding, operation time and gas embolization. The transections and embolization events, evaluated with transesophageal echocardiography, were video recorded. Bleeding and embolization were also assessed on video tapes and operating time measured. Arterial blood gases were recorded on line.

RESULTS

The ultrasonic dissector was least advantageous in terms of bleeding and operation time. Gas embolization was more frequent with the vessel sealing system than with the ultrasonic dissector and ultrasonic shears. During two episodes of gas embolization, pCO2 increased and pO2 and pH decreased.

CONCLUSIONS

Use of all three devices is feasible. Bleeding and operation time are greatest with the ultrasonic dissector. Gas embolization occurs during transection, though in most instances it is completely harmless. Laparoscopic liver surgery with these techniques used may pose a risk of gas embolization with clinical implications. Monitoring for such events is probably to be recommended.

The effects of experimental venous carbon dioxide embolization on hemodynamic and respiratory variables

BACKGROUND

Laparoscopic liver resection is a relatively new surgical procedure. Carbon dioxide (CO2) pneumoperitoneum and laparoscopic liver dissection are recognized as risk factors for CO2 embolism to the pulmonary circulation. The embolization can be difficult to detect and can theoretically increase peri-operative morbidity. The aim of this study was to evaluate the cardiopulmonary effects in a pig model during a time period of 4 h after an experimental CO2 embolization.

METHODS

Eleven piglets were anesthesized. Nine were embolized with a single intravenous injection of 0.4 ml/kg CO2 and two served as controls. Respiratory and cardiovascular variables, including pulmonary artery pressure and cardiac output, were monitored for 4 h after embolization, and arterial blood gases were monitored on-line.

RESULTS

The embolized piglets had an increase in ventilatory dead space, pulmonary vascular resistance and pulmonary artery pressure and a decrease in cardiac output that lasted throughout the 4-h observation time. The mean arterial pressure and heart rate were unchanged. An early sign of embolization was a rapid fall in end-tidal CO2 and P(a)O2 and a rise in P(a)CO2.

CONCLUSION

Negative changes in cardiopulmonary physiology persisted for at least 4 h after a single intravenous CO2 injection, in spite of this gas being highly soluble in blood. This is a more prolonged influence of CO2 embolization than previously described. Extensive monitoring for early detection of an embolization may be recommended to limit morbidity in patients undergoing laparoscopic liver surgery.

Virtual reality colonoscopy simulation: a compulsory practice for the future colonoscopist?

BACKGROUND AND STUDY AIM

As for any manual procedure, the learning curves for medical interventions can have undesirable phases, occurring mostly in the early experience of applying a technique. There have been impressive advances in endoscopic procedures during recent years, and there is an emerging trend that the number of procedures is increasing in parallel with these. In addition, the introduction of screening programs for colorectal cancer will also increase the numbers of procedures needed. Recent developments in medical simulation seem promising with regard to the possibility of "training out" undesirable parts of the learning curve outside the operating room. The aim of this study was to investigate whether the use of the AccuTouch flexible endoscopy simulator improves the early part of the learning curve in colonoscopy training.

METHOD

12 endoscopy trainees, 10 surgeons and two medical gastroenterologists, all with experience in gastroscopy but with no specific colonoscopy experience, were randomly assigned to either simulator training or to a control group. They all received the same theoretical study package and the training group practiced with the AccuTouch colonoscopy simulator until a predefined expert level of performance was reached. All trainees performed their first ten individual colonoscopies described in detail in a separate protocol.

RESULTS

Trainees in the simulator-trained group performed significantly better (P=0.0011) and managed to reach the cecum in 52% of their cases (vs. 19% in the control group), and were 4.53 times more likely to succeed compared with the controls. Additionally, there was a significantly shorter procedure time and less patient discomfort in the hands of the simulator-trained group.

CONCLUSION

Skills acquired using the AccuTouch simulator transfer well into the clinical colonoscopy environment. The results of this trial clearly support the plan to integrate simulator training into endoscopic education curricula.

Randomized clinical trial comparing 5-year recurrence rate after laparoscopic versus Shouldice repair of primary inguinal hernia

BACKGROUND

The Shouldice technique is the 'gold standard' of open non-mesh hernia repair. The aim of this study was to compare 5-year recurrence rates after Shouldice and laparoscopic transabdominal preperitoneal patch (TAPP) repair for primary inguinal hernia.

METHOD

Men with a primary unilateral inguinal hernia were randomized to either Shouldice or TAPP operation. An independent observer scored the surgeons' performance. Follow-up comprised clinical examination after 1 year, a questionnaire after 2 and 3 years, and a clinical examination after 5 years.

RESULTS

Between February 1993 and March 1996, 1183 patients were included. Nine hundred and twenty patients were followed for 5 years, 454 in the TAPP group and 466 in the Shouldice group. Recurrences were evenly distributed between groups throughout the follow-up period. The cumulative recurrence rate after 5 years was 6.6 per cent in the TAPP group and 6.7 per cent in the Shouldice group. Postoperative pain was a risk factor for recurrence after Shouldice operation but not after TAPP repair. There was a correlation between a low surgeon's performance score and recurrence.

CONCLUSION

The 5-year recurrence rate is acceptable, with no difference between TAPP and Shouldice repair. Poor operative performance resulted in a higher recurrence rate. The TAPP operation represents an excellent alternative for primary inguinal hernia repair.

Physical activity questionnaire for adolescents validated against doubly labelled water

OBJECTIVE

To validate a physical activity questionnaire for adolescents (PAQA) adapted from the International Physical Activity Questionnaire (IPAQ).

DESIGN

Energy expenditure was measured during a 14-day period with doubly labelled water (DLW). PAQA was administered as an interview at the end of the period, asking for physical activity in school, during transportation and leisure-time, during a habitual week. Energy expenditure (EE(PAQA)) was calculated as the product of total physical activity + sleep and predicted resting metabolic rate, and was compared to energy expenditure from DLW (EE(DLW)), thermic effect of feeding excluded.

SETTING

Participants were recruited from grade 9 in a compulsory school in Göteborg, Sweden. All data were collected at school, and distribution of DLW and measuring of resting metabolic rate were performed at Sahlgrenska University Hospital.

SUBJECTS

A total of 33 adolescents (16 girls, 17 boys) 15.7 (0.4) y performed all measurements.

RESULTS

: For the whole group, PAQA underestimated energy expenditure by 3.8 (1.7) MJ (P<0.001). There was a strong correlation (r = 0.62, P<0.001) between EE(PAQA) and EE(DLW), but not for boys (r = 0.42, P = 0.090) and girls (r = 0.33, P = 0.22) separately.

CONCLUSIONS

PAQA is not able to predict energy expenditure in Swedish adolescents, largely explained by the amount of unreported time. The ability to rank adolescents energy expenditure is questioned because of the gender effect, although we found a strong correlation for the whole group.

Liver operations in Sweden in 1987-99

BACKGROUND AND AIMS

Liver surgery is developing with new techniques and treatment modalities. The aim of this study is to describe liver surgery over a long period of time in a country with a public health care system.

PATIENTS AND METHOD

A register study including adult patients admitted for liver resection in Sweden (population 8.8 million) selected from the Inpatient Register 1987-99. Additional data were collected from the Swedish Cancer Register and the Cause of Death Register. Analyses of the patients, indications, mortality and causes of death are presented.

RESULTS

2,405 operations were performed (21 per million per year). The most frequent indication was colorectal metastases (27%). The 5-year survival after an operation for primary liver cancer and colorectal liver metastases was 27% and 26%, respectively.

CONCLUSIONS

Few patients were admitted for liver operations compared to expected figures. The survival rates are in conformity with those previously published. With an increasing awareness of the relatively favourable prognosis and the introduction of new methods, the volume of liver operations will probably increase in Sweden.

Radiofrequency ablation in the liver close to the bile ducts: can intraductal cooling offer protection?

BACKGROUND

One complication of radiofrequency ablation (RFA) of the liver is biliary duct damage. Intraductal cooling (IDC) has been proposed as a means of protection.

METHODS

In the first experiment, designed to evaluate the influence of IDC on the RFA procedure per se and on lesion formation, lesions were created in vivo in pig liver with and without IDC. The RFA needle was placed with a 1.5-cm safety margin from the bile ducts. In the second experiment, designed to evaluate the potential protective effects of IDC, lesions were created close to a bile duct with and without IDC.

RESULTS

With the safety margin, the RFA parameters and lesion size were not negatively affected by IDC. Microscopic examination revealed that IDC had a protective effect in most of the lesions created close to a bile duct.

CONCLUSIONS

The IDC procedure was feasible and had no negative effect on the RFA procedure or the lesions. However, the protective effect of IDC was not statistically significant (p = 0.12).

Energy intake in Swedish adolescents: validation of diet history with doubly labelled water

OBJECTIVE

To compare habitual energy intake (EI) estimated from diet history (DH) with total energy expenditure (TEE) measured with doubly labelled water (DLW) in adolescents.

DESIGN

DH included a detailed questionnaire and an interview. TEE was measured during a 14-day period. Adequate (AR), under- (UR) and over-reporters (OR) were defined from the ratio EI/TEE: AR 0.84-1.16, UR <0.84 and OR >1.16.

SETTING

Participants were recruited from grade 9 in a compulsory school in Göteborg, Sweden. All data were collected at school and DLW dosages were distributed at Sahlgrenska University Hospital.

SUBJECTS

A total of 35 adolescents (18 boys, 17 girls), 15.7 (0.4) y.

RESULTS

EI was 11.0 (3.6) MJ and TEE was 11.4 (2.1) MJ (P=0.42). DH was able to rank EI compared to TEE (Spearman's r=0.59, P< or =0.001). For girls, EI was 18% lower (P=0.0067) and for boys, EI was 7% higher (P=0.26) compared to TEE. The 95% limits of agreement for difference between TEE and EI were -5.6 to 6.5 MJ. In total, 20 subjects were defined as AR (57%), nine as UR (26%) and six as OR (17%). Energy from in-between meals was 33% lower (P=0.0043) in UR girls and 57% higher (P=0.026) in OR boys, compared to adequate reporting girls and boys, respectively. In UR girls, energy-adjusted intake (10 MJ) of specific foods did not differ significantly, fat was lower and carbohydrate and vitamin C were higher compared to AR girls (all P<0.05). OR boys had no significant differences in food and nutrient intake in 10 MJ compared to AR boys.

CONCLUSION

The diet history was able to capture EI for the group and to rank subjects. There was a wide individual range in reporting-accuracy related to gender.

SPONSORSHIP

The Ingabritt and Arne Lundberg Foundation, The Wilhelm and Martina Lundgren Foundation.

Long-term results from laparoscopic common bile duct exploration

BACKGROUND

The aim of this study was to evaluate the long-term results after laparoscopic common bile duct exploration (LCBDE).

METHODS

A retrospective review of 175 consecutive patients who underwent attempted LCBDE between 1992 and 1999 was conducted. Laparoscopic transcystic exploration was accomplished in 110 patients and laparoscopic choledochotomy in 52 patients. Conversion to an open common bile duct exploration was required for 13 patients (7.4%). Retained common bile duct stones occurred in eight patients (4.6%). The 30-day postoperative morbidity was 6.9%, and there was no 30-day mortality. All the patients (alive and localized) received a questionnaire evaluating long-term results.

RESULTS

Of the 175 patients, 169 (4 unrelated deaths and 2 patients lost to follow-up evaluation) received and 152 (90%) returned the questionnaire. The follow-up period ranged from 6 to 72 months (median, 36 months). One patient developed recurrent common bile duct stones. There were no signs or evidence of common bile duct stricture in any patient.

CONCLUSION

The LCBDE procedure can be performed without increased risk of late bile duct complications.

Postoperative convalescence after inguinal hernia surgery: prospective randomized multicenter study of laparoscopic versus shouldice inguinal hernia repair in 1042 patients

Interest in inguinal hernia surgery has increased significantly with the introduction of new operating techniques during the past decade. This multicenter study compared short-term results in patients treated by the laparoscopic transabdominal preperitoneal patch technique (TAPP; n = 518) and the Shouldice technique (n = 524). We evaluated demographics, operative data, complications, hospital stay, postoperative pain, use of cs, functional status, sick leave, and complaints up to 3 months postoperatively. The median operating time was shorter in the Shouldice group (55 vs. 65 min), but there were no significant differences in complication rates, and major complications were rare. The hospital stay was 1 day or less in over 98% of cases in both groups, but more operations were performed on outpatient basis in the Shouldice group. In the TAPP group postoperative pain and analgesic consumption were less, postoperative functional status was better, and sick leave was shorter (10 vs. 14 days). These results show that the two methods are equally safe and have few major complications. The TAPP operation is associated with less postoperative pain, better postoperative functional status, and shorter sick leave, but at the price of a longer operating time.

Does training in a virtual reality simulator improve surgical performance?

BACKGROUND

The development of computerized surgical simulators in a virtual reality environment demands models for proper validation. Recent investigations have shown that a virtual reality simulator (MIST-VR) is a reliable tool for the assessment of laparoscopic psychomotor skills and that it improves the automation of the so-called fulcrum effect. Therefore, we set out to determine whether training with the MIST-VR would improve the surgical performance of surgically inexperienced medical students and to see if results obtained in the simulator would correlate with surgical performance.

METHODS

A total of 29 medical students were randomized into two groups. One group received preoperative MIST-VR training. Both groups then performed a simulated laparoscopic appendectomy in a pig. The operations were videotaped and examined by three independent observers.

RESULTS

There was no significant difference in performance between the two groups. The performance with the MIST-VR correlated with the results in surgery.

CONCLUSION

A method that can measure surgical skill, based on the scoring of independent observers who view videotaped performances, seems to be reliable. MIST-VR did not improve the surgical skills of the subjects, but the results with MIST-VR did predict surgical outcome.

Optimal positive end-expiratory pressure (PEEP) settings in differential lung ventilation during simultaneous unilateral pneumothorax and laparoscopy: an experimental study in pigs

BACKGROUND

A combined thoraco-laparoscopic technique for esophageal resection is technically possible, but it requires special attention to ventilation. The positive insufflation pressure normally used in laparoscopy will, when communication between thorax and abdomen is established, create a pneumothorax.

METHODS

We performed an experimental study of differential lung ventilation with different levels of positive end-expiratory pressure (PEEP) settings during thoraco-laparoscopy in anesthetized pigs.

RESULTS

Positive pressure insufflation of carbon dioxide (CO2) resulted in elevated pulmonary capillary wedge pressure, hypercarbia, and respiratory acidosis. Hypoxemia, however, developed only at lower settings of PEEP. Heart rate, mean arterial pressure, and cardiac output remained relatively stable.

CONCLUSION

Pneumopleuroperitoneum under positive CO2 insufflation pressure had adverse effects on blood gases. Hypercarbia, respiratory acidosis, and hypoxemia were early manifestations that occurred even in the presence of hemodynamic stability. The application of PEEP equal to or above CO2 insufflation pressure improved blood gases; in particular, the hypoxia could be avoided. No beneficial effects of differential lung ventilation were documented.

HandPort-assisted laparoscopic splenectomy in massive splenomegaly

BACKGROUND

Laparoscopic splenectomy of normal-sized spleens is performed with increasing frequency. By using a handPort, which allows the intraperitoneal introduction of one surgeon's hand, massively enlarged spleens may also be extirpated via a laparoscopy-assisted technique.

METHODS

Seven patients (54-80 years) with massive splenomegaly (3.5-5.8 kg) underwent handPort-assisted laparoscopic splenectomy. All patients had spleens that extended beyond the umbilicus, hypersplenism, and discomfort in the upper left quadrant due to intractable hematological malignancy.

RESULTS

Both the operation and recovery were uneventful in five of the patients, but one patient had to be converted to an open procedure due to splenic damage and bleeding, and another was reoperated for hemorrhage from a trocar. The handPort allowed splenic protection while the trocars were introduced and instruments changed. It also enabled splenic mobilization, particularly prior to stapling of the hilar structures and dissection of the upper splenic pole.

CONCLUSIONS

HandPort-assisted laparoscopic splenectomy seems to be a viable alternative for massive splenomegaly, but it requires further evaluation with respect to safety, efficacy, and indication.

Hand-assisted laparoscopic surgery (HALS) with the HandPort system: initial experience with 68 patients

OBJECTIVE

To evaluate the feasibility and potential benefits of hand-assisted laparoscopic surgery with the HandPort System, a new device.

SUMMARY BACKGROUND DATA

In hand-assisted laparoscopic surgery, the surgeon inserts a hand into the abdomen while pneumoperitoneum is maintained. The hand assists laparoscopic instruments and is helpful in complex laparoscopic cases.

METHODS

A prospective nonrandomized study was initiated with the participation of 10 laparoscopic surgical centers. Surgeons were free to test the device in any situation where they expected a potential advantage over conventional laparoscopy.

RESULTS

Sixty-eight patients were entered in the study. Operations included colorectal procedures (sigmoidectomy, right colectomy, resection rectopexy), splenectomy for splenomegaly, living-related donor nephrectomy, gastric banding for morbid obesity, partial gastrectomy, and various other procedures. Mean incision size for the HandPort was 7.4 cm. Most surgeons (78%) preferred to insert their nondominant hand into the abdomen. Pneumoperitoneum was generally maintained at 14 mmHg, and only one patient required conversion to open surgery as a result of an unmanageable air leak. Hand fatigue during surgery was noted in 20.6%.

CONCLUSIONS

The hand-assisted technique appeared to be useful in minimally invasive colorectal surgery, splenectomy for splenomegaly, living-related donor nephrectomy, and procedures considered too complex for a laparoscopic approach. This approach provides excellent means to explore, to retract safely, and to apply immediate hemostasis when needed. Although the data presented here reflect the authors' initial experience, they compare favorably with series of similar procedures performed purely laparoscopically.

Antireflux surgery in Sweden, 1987-1997: a decade of change

BACKGROUND

The aim of this study was to analyse whether new therapeutic options--the introduction of proton-pump inhibitors (PPI) in 1989 and the laparoscopic technique in 1992--altered the surgical treatment of gastro-oesophageal reflux disease (GORD) in Sweden.

METHODS

Data obtained from the Centre for Epidemiology (EpC) on patients undergoing surgery for GORD from 1987 to 1997 was analysed, and the information was validated with a questionnaire to all surgical departments.

RESULTS

The questionnaire gave a response rate of 94%, and the figures corresponded well with those obtained from the EpC. In 1987, 456 antireflux procedures were performed. Ten years later this figure had increased to 1303. This approximately threefold increase started before the introduction of PPI and was even more pronounced during the following few years. The development of laparoscopic antireflux surgery did not alter this increase. In 1997, 76% of the procedures were performed laparoscopically. The fundoplication rate rose from 5.5 to 12.7 procedures/100,000 inhabitants. The rates varied greatly among different counties; 7 of 23 still had a fundoplication rate of less than 10 in 1997. The median number of procedures per hospital in 1997 was 10. Only two departments accomplished more than 50 antireflux procedures.

CONCLUSION

Within 5 years the laparoscopic technique replaced the open procedure as the method of choice. However, the increase in the frequency of antireflux surgery was apparent even before the introduction of laparoscopy.

[Laparoscopic living-donor nephrectomy. A small study shows positive results, but the procedure still lacks satisfactory evaluation]

Retrospective analysis and comparison of a small series of 12 laparoscopic live donor nephrectomy (LapLDN) procedures with 15 open live donor nephrectomies, all 27 performed in 1998, showed operating time to be significantly longer but sick leave shorter and hospital stay somewhat shorter in the LapLDN subgroup. One patient in the open procedure subgroup developed herniation and scar discomfort, and in one LapLDN procedure severe bleeding necessitated conversion to open nephrectomy. All kidneys in both subgroups manifested immediate resumption of function after transplantation. Though the LapLDN procedure has yet to be satisfactorily evaluated, the present findings were predominantly in its favour.

Laparoscopic common bile duct exploration

OBJECTIVE

To explore the feasibility of laparoscopic techniques for the removal of common bile duct (CBD) stones.

DESIGN

Retrospective analysis.

SETTING

University hospital, Sweden.

SUBJECTS

39 patients who underwent laparoscopic common bile duct exploration, either by a transcystic technique or by choledochotomy, between September 1992 and April 1995.

INTERVENTIONS

Cholecystectomy, intraoperative cholangiography, and removal of CBD-stones by a transcystic technique (n=22), laparoscopic choledocholithotomy (n=11), or after conversion to open choledocholithotomy (n=6).

MAIN OUTCOME MEASURES

Stone clearance rates, operative time, complications, and postoperative hospital stay.

RESULTS

Stone removal was achieved in 32/39 patients (82%) by a laparoscopic approach. Reasons for failure were early in our experience, and the result of technical difficulties or stones that were too large for the transcystic approach, or with impacted stones at choledochotomy. Postoperative morbidity was low (n=4, 10%) with no mortality.

CONCLUSIONS

Common bile duct stones can be removed in a large proportion of patients undergoing laparoscopic cholecystectomy, either by a laparoscopic transcystic technique or through a laparoscopic choledochotomy. The laparoscopic techniques need further evaluation, preferably in prospective multicentre trials comparing other treatment strategies including endoscopic sphincterotomy.

A survey of surgical treatment of gallstone disease and the diffusion of laparoscopic surgery in Sweden 1992-93

OBJECTIVE

To study the diffusion of laparoscopic biliary surgery in Sweden, 1992-93.

DESIGN

A prospective survey of all biliary surgery for gallstone disease recorded for 8 weeks in 1992 and the same period in 1993.

SETTING

All surgical departments in Sweden.

SUBJECTS

A consecutive series of 1938 patients in 1992 and 1748 patients in 1993.

MAIN OUTCOME MEASURES

The changing indications, diffusion, morbidity, mortality, postoperative and hospital stay after laparoscopic cholecystectomy (LC) in Sweden in 1992 compared with 1993.

RESULTS

Despite the spread of LC, the indications did not change between 1992 and 1993 (p=0.31). The total number of cholecystectomies decreased from 1938 in 1992 to 1748 in 1993. The overall percentage of laparoscopic cholecystectomies (LCs) increased from 74.7% to 81.2% (p <0.001) between 1992 and 1993. Postoperative morbidity and mortality after LC did not differ between 1992 and 1993, but the total morbidity was 9.0% in 1992 and 7.0% in 1993 (p=0.02). Mortality for all cholecystectomies did not change over the periods, being 0.6% in 1992 and 0.2% in 1993 (p=0.07). The numbers of LCs done in any hospital were divided in two groups, 20 or fewer and 21-80. In the smaller group, the postoperative morbidity was 7.1% and in the larger group it was 7.0%, (p=0.9). The postoperative mortality was 0.1% in both groups. The postoperative and total hospital stays of all cholecystectomies decreased from 3.4 days in 1992 to 2.9 days in 1993 (p=0.001) and from 5.0 in 1992 to 4.4 days in 1993 (p < 0.001), respectively. The postoperative and total hospital stays of LCs decreased from 2.0 in 1992 to 1.8 days in 1993 (p=0.009) and from 3.3 in 1992 to 2.9 days in 1993 (p=0.007), respectively.

CONCLUSION

Despite the introduction and diffusion of the new technology, LC, the indications for surgery did not change and the number of cholecystectomies did not increase from 1992 to 1993. The morbidity and mortality of LC and the mortality of all cholecystectomies were unchanged between 1992 and 1993, but the morbidity for all cholecystectomies decreased. The number of LC or all cholecystectomies done in any particular hospital were not related to morbidity or to mortality.

Population-based study of cancer risk and relative survival following sphincterotomy for stones in the common bile duct

BACKGROUND

Endoscopic sphincterotomy was introduced in 1974 as a procedure for removing stones in the common bile duct. To assess the long-term risk of cancer and relative survival, all patients who underwent this procedure at six different hospitals between 1977 and 1985 were identified.

METHODS

A total of 992 patients was identified and they were followed by linkage to the Swedish Death Registry and the Swedish Cancer Registry.

RESULTS

At 1 year or more after sphincterotomy there was no increased risk of cancer in the liver, gallbladder, bile duct or pancreas (standardized incidence ratio 0.80, 95 per cent confidence interval 0.3-1.9). Relative survival was lowered slightly in the first year after sphincterotomy, but did not differ from that of the background population thereafter.

CONCLUSION

Endoscopic sphincterotomy for stones in the common bile duct does not appear to affect the risk of cancer in the pancreas, liver or bile ducts, nor does it affect long-term survival.

[Laparoscopy possible even in cholelithiasis. Results for 96 patients from three different hospitals are reviewed]

At laparoscopic cholecystectomy, a procedure routinely used at Swedish surgery departments today, common bile duct stones are found to be present in 5-10 per cent of cases. During recent years, several alternative procedures have been evolved for the management of duct stones, such as operative or postoperative endoscopic sphincterolomy, or conversion to open surgery and choledochotomy. The article gives an account of laparoscopic treatment of common bile duct stones, and results obtained in 96 patients from three surgery departments in Sweden. Three different primary techniques were used: saline flushing via the cholangiography catheter, after intravenous injection of 1 mg of glucagon (in six cases of small stones); transcystic common duct exploration (TCDE), with cholodochoscopy and a Dermia basket (68 cases); and laparoscopic choledochotomy and choledochoscopy (22 cases). The success rate was 88 per cent (84/96), and mortality zero. In many cases the postoperative course was similar to that of patients undergoing laparoscopic cholecystectomy alone. We recommend TCDE in cases of common bile duct stones of no more than 8-9 mm in diameter, and where the cystic duct is large. Single-stage laparoscopic treatment of bile duct stones seems to be a safe and effective method of dealing with two problems in the same setting, and is an important alternative in the management of duct stones.

A cost-minimization analysis of laparoscopic cholecystectomy versus open cholecystectomy

BACKGROUND

Earlier economic analyses have evaluated charges but not costs, and have not considered the cost of production losses associated with open and laparoscopic cholecystectomy. This study attempted to accomplish an economic evaluation of open versus laparoscopic cholecystectomy from the point of view of society.

METHODS

A cost-minimization analysis, using a clinical decision model, was performed. The data used were taken from different clinical studies, Swedish national registers, local patient statistics, and hospital accounting systems. The direct and indirect costs were measured.

RESULTS

Laparoscopic cholecystectomy resulted in cost savings per patient amounting to about 2,400 SEK (as of 31 August 1994, Pound = 11.90 SEK; $1 = 7.76 SEK) compared with open surgery.

CONCLUSIONS

From the point of view of society, laparoscopic cholecystectomy was a cost-saving strategy if at least 68 patients were operated on yearly. However, with regard to hospital costs, open cholecystectomy was less expensive than laparoscopic cholecystectomy.

Effects of pneumoperitoneum on splanchnic hemodynamics: an experimental study in pigs

OBJECTIVE

To study the effects on splanchnic haemodynamics of pneumoperitoneum induced by carbon dioxide insufflation.

DESIGN

Controlled experimental study.

ANIMALS

11 Pigs weighing 19-30 kg.

INTERVENTION

The animals were divided into a control group (n = 4) and a experimental group (n = 7). Experimental animals were subjected to stepwise increasing intra-abdominal pressure from 0 mm Hg to 25 mm Hg by carbon dioxide insufflation.

MAIN OUTCOME MEASURES

Portal venous blood flow, portal venous blood pressure, portal/hepatic vascular resistance, and gastrointestinal vascular resistance.

RESULTS

At 25 mm Hg portal venous blood flow was reduced (66% of baseline), and portal venous blood pressure and portal/hepatic vascular resistance were increased (360% and 650% of baseline, respectively). The increase in gastrointestinal vascular resistance was less pronounced.

CONCLUSIONS

Increased intra-abdominal pressure caused significant changes in the splanchnic haemodynamics. The risk was greater if the intra-abdominal pressure exceeded 15 mm Hg.

Laparoscopic suture rectopexy

PURPOSE

This article describes a technique for laparoscopic suture rectopexy and assesses the postoperative results.

METHODS

The rectum was fixed to the presacral fascia with five to six sutures. The procedure was performed using a laparoscope in four patients.

RESULTS

There were no postoperative complications. In one patient a large enterocele was observed during the operation. This patient developed a recurrence about one month postoperatively.

CONCLUSION

Laparoscopic suture rectopexy might be an alternative to open rectopexy for patients with isolated rectal prolapse.

Hepatic extraction of hyaluronic acid in porcine peritonitis

The hepatic extraction of hyaluronic acid (HA) was studied in porcine fecal peritonitis in two groups of animals given various amounts of volume substitution. There was a progressive decrease in hepatic blood flow (QH) and a corresponding increase in the plasma concentration of HA in arterial blood over a 5-hour observation period, less pronounced in animals given more volume substitution. While hepatic clearance of HA decreased, the extraction ratio over the liver was not altered. The extracted amount of HA, which at steady state reflects the turnover of HA, was also unchanged. There was a significant correlation between QH and arterial HA concentration (r = 0.57; p < 0.05). The data suggest that the arterial HA concentration in sepsis reflects QH rather than an altered ability of the liver to eliminate HA.

Laparoscopic versus open cholecystectomy: hospitalization, sick leave, analgesia and trauma responses

Laparoscopic cholecystectomy has rapidly become established as the treatment of choice for cholecystolithiasis. There is very little evidence, however, to support the claimed benefit to patients. In the present study 30 consecutive patients below the age of 65 years without acute cholecystitis and with no signs of common bile duct stones were randomized to laparoscopic or conventional open cholecystectomy. Median (interquartile range) intravenous consumption of pethidine with a patient-controlled injection device between 13 and 24 h after surgery was 125 (62-175) mg in patients who underwent the laparoscopic procedure and 200 (150-250) mg in those who had open operation. Urinary adrenaline and cortisol levels as well as those of plasma glucose, C-reactive protein and interleukin 6 were increased after surgery in both groups of patients, but without any significant difference between them. The mean(s.d.) duration of postoperative hospital stay (2.8(0.8) versus 1.8(0.6) days) and sick leave (24.0(4.4) versus 11.7(4.1) days) was significantly longer with open than laparoscopic cholecystectomy. The findings demonstrate obvious advantages of laparoscopic surgery as regards postoperative pain and convalescence, although factors reflecting the magnitude of trauma did not differ.

Ultrasound monitored laser-induced local hyperthermia in the liver. An experimental study on pigs

Ultrasound (US) was used to monitor the size of tissue necrosis generated by Nd-YAG laser-induced local interstitial hyperthermia and tissue coagulation in 8 normal pig livers. Four treatments were done in each liver with 4 different energy settings. The size of the tissue necrosis measured on specimens was compared to the size measured on US. The laser energy caused a round tissue necrosis with some charring in the centre surrounded by a zone of white necrosis and a thin border of hyperaemia. A good correlation was found between the true and US-measured size of the necrosis diameters. It therefore seems possible to safely guide and monitor local laser hyperthermia in the liver with real-time US. The water-cooled quartz fibre used in this study has, however, some limitations.

Inhibition of CD18-dependent adherence of polymorphonuclear leukocytes does not affect liver oxygen consumption in fecal peritonitis in pigs

We tested the hypothesis that circulating polymorphonuclear leukocytes (PMNs), adhering to endothelium of the liver vascular bed are involved in the alterations of the liver oxygen delivery (DO2) and consumption (VO2) that is a result of fecal peritonitis in pigs. Twenty-two pigs were divided into three groups. Animals in group I (n = 7) served as controls. Fecal peritonitis was induced in groups II (n = 7) and III (n = 8). Animals in group III were pretreated with IB4, a monoclonal anti-CD18 antibody inhibiting adherence of PMNs to the endothelium. Peritonitis increased liver VO2 in groups II and III in spite of decreased liver DO2. In group I, circulating PMNs increased during the experimental period. Sepsis caused a decrease in the number of circulating PMNs in group II, an effect that was fully counteracted in group III, where the number of PMNs rose to control level. Myeloperoxidase activity and morphometric determination of PMN infiltration in liver biopsies virtually paralleled the circulating PMN count. Although fecal peritonitis is followed by a CD18-dependent leukopenia that can be counteracted by pretreatment with an anti-CD18 antibodies, this treatment does not affect the alteration in liver VO2 and DO2 observed.

[Laparoscopic surgery. A shift in paradigm?]

Since it was first introduced at the beginning of the century, laparoscopy has been developed by pioneers in the field of gynaecological surgery from a diagnostic aid to a high tech tool for use in various branches of surgery. In the near future, this rapidly developing technique, with three-dimensional video and robot-assisted surgery, will require well planned theoretical and practical training.