Laparoscopic approach to small intestinal obstruction in children: a preliminary experience.

SUMMARY: The use of laparoscopy for the management of acute intestinal obstruction is increasing. It has potential advantages over classic laparotomy. The objective of the current study was to evaluate the feasibility and outcome of laparoscopic management of small intestinal obstruction. A retrospective review of 30 children admitted for attempt of laparoscopic management of acute intestinal obstruction was performed. Their mean age was 6.7 +/- 1.73 years. Of the 30 laparoscopic attempts, 20 (66.7%) were performed successfully, whereas 10 patients (33.3%) needed a conversion to laparotomy because of inadequate laparoscopic visualization in 6 cases, gangrenous bowel in 2 cases, and inability to relieve the obstruction laparoscopically in 2 cases. There were no intra-or postoperative complications in the laparoscopic group. The mean operative time for the laparoscopic release of intestinal obstruction was 68 +/- 12.32 minutes and 102 +/- 9.67 minutes for the converted cases. The mean time of return of bowel function and mean hospital stay in the laparoscopic release of intestinal obstruction were significantly shorter. The study showed that laparoscopic release of intestinal obstruction in children is worthy of attempting initially. It is a feasible, effective, and safe alternative to laparotomy for most patients with acute intestinal obstruction.

Randomized clinical trial of stapled versus Milligan-Morgan haemorrhoidectomy.

BACKGROUND: The introduction of a stapling technique for the treatment of haemorrhoids has the potential for less postoperative pain, a short operating time and an early return to full activity. The outcome of stapled haemorrhoidectomy was compared with that of current standard surgery in a randomized controlled study. METHODS: Two hundred patients were randomized to either stapled haemorrhoidectomy (n = 100) or Milligan-Morgan haemorrhoidectomy (n = 100) between March 1997 and December 1998. Each patient received standardized postoperative analgesic and laxative regimens, and completed a linear analogue pain score every 6 h during the first day after operation, after the first motion and daily until the end of the first week. Operating time, frequency of postoperative analgesic intake, hospital stay, time to return to normal activity and postoperative complications were also recorded. RESULTS: The mean(s.d.) age of patients in the stapled and surgical groups was 44.1(3.2) and 49.1(12.2) years respectively. The stapled group had a shorter operating time, less frequent postoperative analgesia intake, shorter hospital stay and earlier return to normal activity. Early and late complications, and functional outcome were better in the stapled group. CONCLUSION: Use of a circular stapler in the treatment of haemorrhoidal disease was safe, and was associated with fewer complications than conventional haemorrhoidectomy.

Hepatic indocyanine green uptake and excretion in a rabbit model of steatosis.

Transplantation of a fatty liver is associated with a higher incidence of primary non-function of the graft. Indocyanine green (ICG) has been used for assessing hepatic dysfunction but not for quantifying liver steatosis. New Zealand white rabbits were fed a normal diet (group A) or a high-cholesterol (2%) diet for 4, 8, and 12 weeks in groups B, C, and D, respectively. Laparotomy was performed for liver exposure. Hepatic artery, portal vein, and total blood flow, hepatic microcirculation, portal pressure, liver function parameters, and blood cholesterol levels were measured. The hepatic ICG concentration was measured using near-infrared spectroscopy, and its uptake and excretion rates were calculated. The severity of steatosis was assessed from liver biopsy specimens by a semiquantitative grading system. Cholesterol feeding resulted in mild steatosis after 4 weeks and in moderate steatosis after 8 and 12 weeks. Mild steatosis was associated with insignificant changes in haemodynamic parameters, liver function, and ICG handling as compared with controls. Moderate steatosis caused a significant reduction in portal and total hepatic blood flow and microcirculation with a significant increase in hepatic artery flow and portal pressure. These haemodynamic changes were associated with a significant alteration in liver function tests. With moderate steatosis, ICG uptake and excretion were significantly reduced. The ICG uptake rate significantly correlated with total blood flow and microcirculation. The ICG excretion rate significantly correlated with the changes in bilirubin, liver enzymes, and albumin. Direct ICG quantification by near-infrared spectroscopy could be used to assess the severity of hepatic steatosis by reflecting impaired parenchymal perfusion and liver dysfunction.

Laparoscopic appendectomy in children: evaluation of different techniques.

Patients and surgeons frequently opt for laparoscopic appendectomy for treatment of acute appendicitis. Clinical studies have shown this approach to be a reasonable alternative to open appendectomy. The objective of the current study was to assess the outcome of laparoscopic appendectomy using three different techniques. The study sample consisted of 150 children with acute appendicitis who underwent surgery at Al-Azhar University Hospitals, Cairo, Egypt, and at Al Mishary Hospital in Riyadh, Saudi Arabia, between October 1997 and October 1999. The patients were allocated to undergo extracorporeal laparoscopic appendectomy, Endoloop laparoscopic appendectomy, or EndoGIA (Ethicon Endo-surgery, Inc., Cincinnati, OH, USA) laparoscopic appendectomy. All patients were assessed for the severity of the disease at baseline using clinical and hematologic indicators. The ages of the children ranged from 7 to 14 years, with a mean of 10 years (SD, 2.14 years). Of the children, 55.3% were female. The results showed that children who underwent laparoscopic appendectomy using the EndoGIA had statistically significant shorter operating times, did not have complications, and had the shortest duration of hospital stay (although duration of hospital stay did not reach the statistically significant level of P > 0.05). Therefore, the study showed that laparoscopic appendectomy using the EndoGIA is the procedure that is most recommended, except for the relatively high cost of the disposable materials. Endoloop laparoscopic technique was the second most preferable procedure, and the least preferred procedure was extracorporeal laparoscopically assisted appendectomy. The major drawback of the last technique is the high frequency of complications. Endoloop laparoscopic appendectomy with a purse-string suture can be performed safely if the EndoGIA is not available.

Assessment of hepatic ischaemia reperfusion injury by measuring intracellular tissue oxygenation using near infrared spectroscopy.

AIMS/BACKGROUND: Hepatic ischaemia/reperfusion (I/R) injury is a major cause of liver damage during liver surgery and transplantation. The relationship between the severity of I/R injury and the degree of intracellular hypoxia has not been investigated. METHODS: New Zealand white rabbits were used in 4 groups (n=6 each). At laparotomy, left lobe hepatic ischaemia was produced for 30, 45, or 60 min followed by 60 min reperfusion and compared with controls. Liver function, bile flow, and flow in the hepatic microcirculation (HM) were measured. Near infrared spectroscopy (NIRS) was used to monitor hepatic oxyhaemoglobin (HbO2), deoxyhaemoglobin (Hb), and cytochrome oxidase (Cyt Ox). RESULTS: I/R injury produced deranged liver function tests, reduced bile flow, and reduced flow in the microcirculation in comparison with controls. During ischaemia, HbO2 and Cyt Ox were significantly reduced in comparison with controls. After reperfusion, a biphasic change in tissue oxygenation was observed, with an initial increase in HbO2 and Cyt Ox followed by a progressive reduction. The reduction in tissue oxygenation with ischaemia and reperfusion paralleled the ischaemia time. After I/R, the changes in Cyt Ox (intracellular oxygenation) significantly correlated with the parameters of hepatocellular injury to a higher degree than HbO2 (extracellular oxygenation). CONCLUSION: This study shows the potential of monitoring the degree of I/R injury by measuring hepatic tissue intracellular oxygenation.

Measurement of hepatic tissue hypoxia using near infrared spectroscopy: comparison with hepatic vein oxygen partial pressure.

Hepatic hypoxia occurs during liver surgery and transplantation. The critical level associated with irreversible hepatocellular damage is unknown. Measurement of hepatic tissue oxygenation and hepatic vein oxygen partial pressure (HVPO(2)) reflects oxygen supply and consumption. Near infrared spectroscopy (NIRS) can be used to monitor hepatic oxyhaemoglobin (HbO(2)), deoxyhaemoglobin (Hb) and cytochrome oxidase (Cyt Ox) oxidation. This study compared regional hepatic tissue oxygenation (HbO(2), Hb and Cyt Ox) using NIRS with HVPO(2). The use of tissue oxygenation measured by NIRS and HVPO(2) as indicators of hepatic tissue hypoxia was also investigated. Large Landrace pigs (n = 5) underwent laparotomy and liver exposure. Systemic and hepatic haemodynamics were monitored continuously. NIRS probes were placed on the liver to record continuously HbO(2), Hb and Cyt Ox. Graded hypoxaemia was achieved by stepwise reduction of the fraction of inspired oxygen (FiO(2)) from 30% (baseline) to 4%. A significant decrease in hepatic arterial blood flow and total hepatic blood flow was seen with severe hypoxaemia while there was no significant change to portal vein blood flow. Oxygen partial pressures in the hepatic artery, portal vein and hepatic vein decreased progressively with all grades of hypoxaemia. There was an immediate reduction of hepatic HbO(2) and simultaneous increase in hepatic Hb with all grades of hypoxaemia. Hepatic Cyt Ox was reduced significantly only with FiO(2) < or =10%. A significant correlation (p<0.001) was found between the changes in hepatic oxygenation parameters measured by NIRS and HVPO(2). HVPO(2) measurement did not predict the reduction in intracellular tissue oxygenation demonstrated by NIRS with a decrease of Cyt Ox oxidation. In conclusion there was a good correlation between the tissue oxygenation parameters measured by NIRS and HVPO(2). However, the reduction of intracellular oxygenation found with severe hypoxaemia was demonstrated only by NIRS.

Effect of liver blood flow and function on hepatic indocyanine green clearance measured directly in a cirrhotic animal model.

BACKGROUND: Peripheral blood clearance of indocyanine green (ICG) has been used as a test of liver function but gives little information on biliary excretion. Hepatic ICG uptake and clearance can be measured directly by near-infrared spectroscopy (NIRS). Direct ICG measurement has not previously been correlated with liver blood flow and function in cirrhosis. METHODS: Two groups of New Zealand white rabbits (n = 12) underwent laparotomy for liver exposure. Cirrhosis was induced by feeding animals (n = 6) with a high-cholesterol (2 per cent) diet for 16 weeks. Hepatic blood flow and microcirculation were measured. Hepatic ICG concentration was measured directly using NIRS probes on the liver surface. From the ICG concentration-time curve, hepatic ICG uptake and excretion rates were calculated by a non-linear least square curve fitting method. RESULTS: There was a significant reduction in ICG uptake rate (mean(s.d.) 0.300(0.130) versus 2.040(0.420) min-1; P = 0.0001) and ICG excretion rate (0.007(0.009) versus 0.227(0.096) min-1; P = 0. 002) in cirrhotic animals. The hepatic ICG uptake rate correlated with hepatic blood flow and flow in the microcirculation (r = 0.81, P = 0.002; r = 0.92, P < 0.001, respectively). The hepatic ICG excretion rate was significantly associated with indicators of impaired liver function including bilirubin (r = - 0.86, P = 0.0004), aspartate aminotransferase (r = - 0.81, P = 0.001) and lactate dehydrogenase (r = - 0.83, P = 0.0008). CONCLUSION: ICG uptake measured directly by NIRS reflects the reduced liver blood flow and perfusion in cirrhosis and its excretion correlates with the degree of liver parenchymal dysfunction. This technique may allow a more accurate method of liver function assessment than peripheral blood ICG clearance.

Wavelet-based noise removal for biomechanical signals: a comparative study.

The purpose of this paper is to present wavelet-based noise removal (WBNR) techniques to remove noise from biomechanical acceleration signals obtained from numerical differentiation of displacement data. Manual and semiautomatic methods were used to determine thresholds for both orthogonal and biorthogonal filters. This study also compares the performance of WBNR approaches with four automatic conventional noise removal techniques used in biomechanics. The conclusion of this work is that WBNR techniques are very effective in removing noise from differentiated signals with sharp transients while leaving these transients intact. For biomechanical signals with certain characteristics, WBNR techniques perform better than conventional methods, as indicated by quantitative merit measures.

Experimental study of liver dysfunction evaluated by direct indocyanine green clearance using near infrared spectroscopy.

BACKGROUND: Blood clearance of indocyanine green (ICG) is an objective test of liver function. Hepatic ICG clearance can now be measured directly using near infrared spectroscopy (NIRS). The aim of this study was to evaluate measurement of hepatic ICG clearance by NIRS in an animal model of acute hepatic dysfunction. METHODS: New Zealand white rabbits (n = 36) underwent laparotomy for liver exposure. Hepatic blood flow and microcirculation were measured along with hepatic ICG concentration by NIRS. Hepatic ICG clearance was measured in groups of six animals after reduction of the hepatic blood flow by hepatic artery occlusion and portal vein partial occlusion, lobar ischaemia and reperfusion (I/R), colchicine administration and bile duct ligation. Hepatic ICG uptake and excretion rates were calculated by a non-linear least square curve fitting method from the ICG concentration-time curve. RESULTS: There was a significant positive correlation between hepatic ICG rate of uptake and both hepatic blood flow and microcirculation (r = 0.79, P = 0.0001; r = 0.59, P = 0.005 respectively). I/R resulted in a significant reduction of both the rates of ICG uptake (mean(s.d.) 0. 85(0.59) min-1; P = 0.0002 versus control) and ICG excretion (0. 020(0.006) min-1; P = 0.02 versus control). Colchicine decreased the rate of hepatic ICG excretion (0.030(0.010) min-1; P = 0.02 versus control) as did bile duct ligation (0.002(0.001) min-1; P = 0.01 versus control). CONCLUSION: Measurement of hepatic ICG clearance by NIRS is a promising technique for assessing hepatic parenchymal dysfunction and may have application in liver surgery and transplantation.

Effect of graded hypoxia on hepatic tissue oxygenation measured by near infrared spectroscopy.

BACKGROUND/AIMS: In liver transplantation ischaemia-reperfusion injury of the graft reduces hepatic tissue oxygenation which has prognostic value for patient survival. Near infrared spectroscopy (NIRS) can measure extracellular (haemoglobin oxygenation) and intracellular tissue oxygenation (cytochrome oxidase oxidation). However, it has not been validated for measuring hepatic tissue oxygenation in an experimental model with graded hypoxia. METHODS: New Zealand White rabbits (2.9+/-0.3 kg, n=9) underwent laparotomy for liver exposure. Heart rate, blood pressure, temperature, arterial blood pH and blood gas partial pressures were monitored during the experiments. Near infrared spectroscopy probes were placed on the liver surface to record continuously hepatic oxyhaemoglobin, deoxyhaemoglobin and cytochrome oxidase oxidation. Graded hypoxia was achieved by stepwise reduction of the inspired oxygen from 15 to 4%. During recovery from hypoxia 30% oxygen was administered. RESULTS: There was an immediate reduction of hepatic oxyhaemoglobin with hypoxia and a simultaneous increase of hepatic deoxyhaemoglobin. Hepatic oxyhaemoglobin showed a positive correlation with arterial oxygen pressure (r=0.77, p<0.001). Hepatic deoxyhaemoglobin showed a negative correlation with arterial oxygen pressure (r=-0.75, p<0.001). Hepatic cytochrome oxidase decreased significantly with an inspired oxygen of 10% or less and showed a positive correlation with arterial oxygen pressure (r= 0.90, p<0.001). CONCLUSIONS: Near infrared spectroscopy is an effective method for monitoring hepatic extracellular and intracellular tissue oxygenation.

Changes in tissue oxygenation of the porcine liver measured by near-infrared spectroscopy.

Near-infrared spectroscopy (NIRS) is a novel method for the measurement of tissue oxygenation and may have a role in monitoring liver oxygenation and viability. The aim of this study is to validate the application of NIRS for monitoring hepatic tissue oxygenation. Large Landrace pigs (n = 12) underwent laparotomy and liver exposure. Total hepatic blood flow (THBF) was measured by the Transonic Medical Flowmeter system. NIRS probes were placed on the liver surface to continuously record changes in hepatic tissue oxyhemoglobin (HbO2), deoxyhemoglobin (Hb), and the reduction-oxidation state of cytochrome oxidase (Cyt Ox). Reduction of hepatic tissue oxygenation was achieved by hepatic vascular inflow occlusion (n = 6) or reduction of inspired oxygen (FIO2; n = 6). The THBF changes correlated significantly with hepatic HbO2 (r = 0.84; P <.001) and Cyt Ox (r = 0.88; P <.001). With reduction of FIO2, a significant correlation was found between arterial oxygen saturation and hepatic HbO2 and Hb (r = 0.99 and r = -0.99, respectively; P <.0001). NIRS measurement of liver parenchymal oxygenation correlates well with changes in liver blood flow and arterial oxygenation.

The motion path of the digits.

This study investigates whether the path taken by the fingertips of the human hand during unrestricted flexion and extension follows a precise mathematical pattern: an equiangular spiral. Eight normal subjects participated in the study. Subjects performed numerous flexion and extension trials at a random speed. Motion was recorded by a 6-camera, 3-dimensional motion analysis system with 24 retroreflective markers affixed to the dominant hand at predetermined locations. Four hundred eighty flexion-extension arcs were analyzed. We used the coefficient of multiple determination to compare the flexion and extension motion arc of each finger to an equiangular spiral curve derived mathematically. Our results indicate that the path of the hand during flexion and extension closely follows the path of an equiangular spiral with the coefficient of multiple determination values consistently above 0.95.

Quantification of the morphological features of a full microvascular network.

Investigations into the changes that occur in microvasculature following the surgical procedure called delay have brought about the need for a computer system capable of quantifying the morphological features of a full microvascular network in terms of average vessel length, diameter, and tortuosity. Both the formulaic conventions that have been developed to measure these quantities as well as their implementation in the form of a HP-9000/UNIX based computer software system that we developed specifically for this purpose are discussed. Reliability studies performed using the final system to measure the microcirculatory network of a mouse latissmus dorsi muscle (LDM) showed 95% confidence intervals within 5% of means and coefficients of variability within 7% of means for all quantities measured in large (150-300 microns), medium (50-150 microns), and small (< 50 microns) diameter vessels. These variations were significantly smaller than the changes that were observed in a preliminary study comparing these microvascular network parameters before and after delay in the hairless mouse LDM, showing the proposed quantification methods to be well suited to the study of the microvascular changes following delay. It is hoped that the formulaic conventions, implementation process and reliability data will provide a useful comparison for other researchers interested in measuring similar features of microcirculatory networks.