Resected Surface Research Articles

Use of mouse liver mesothelial cells to prevent postoperative adhesion and promote liver regeneration after hepatectomy

Repeated hepatectomy is widely accepted as one of the most effective curative treatment for recurrent hepatocellular carcinoma or liver metastasis from colorectal cancer. It has, however, two critical issues; postoperative adhesion and decrease of liver regenerative capacity. Postoperative adhesion makes surgical operations technically more demanding, leading to increased mortality and morbidity rates. Although the liver has a remarkable regenerative ability, volume and functional restoration after multiple repeated hepatectomy is not generally complete. So a new procedure that overcomes these two issues is required. We examined if a fetal liver mesothelial cells (FL-MCs) sheet could solve these two clinical issues simultaneously. We established a novel mouse hepatectomy model that reproduces postoperative adhesion on the resected liver surface. We isolated FL-MCs from mouse fetal liver and prepared a cell sheet. The FL-MCs sheet was then transplanted to the resected liver surface. The FL-MCs sheet effectively prevented postoperative adhesion by expressing PCLP1, one of the transmembrane sialomucin family proteins and by activating the fibrinolytic system. Furthermore, the FL-MCs sheet facilitated liver regeneration by providing growth factors for hepatocytes, allowing quick recovery of liver weight and function. Additionally, we showed that an allogeneic FL-MCs sheet was as effective as a syngeneic cell sheet. We demonstrate that the FL-MCs sheet is able to not only prevent postoperative adhesion but also promote liver regeneration in both syngeneic and allogeneic transplantation, and hence FL-MCs may serve as a potentially useful cell source for regenerative medicine after hepatectomy.

Is a "sulcus cut" technique effective for determining the level of distal femoral resection in total knee arthroplasty?

Determining the level of distal femoral resection is crucial when performing total knee arthroplasty (TKA). However, variations in distal femoral resection are encountered unexpectedly. A "sulcus cut" technique is sometimes used to determine the level of distal femoral resection, but its effectiveness has not been evaluated. The aim of this study was to examine the reliability of the sulcus cut technique using computer simulation for preoperative planning. This study group comprised 40 knees in 34 patients (22 women, 12 men) scheduled for TKA. The preoperative planning software of a computed tomography (CT)-based navigation system was used. We determined the resected level of the femur so that the bone-implant interface of the femoral component was adjusted to the deepest subchondral bone of the trochlear groove in coronal CT images. We then measured each perpendicular distance from the resected surface of the proximal femur to the most distal point of the lateral and medial femoral condyles. The mean distances of the distal-lateral and distal-medial condylar resections from the femoral sulcus were 7mm (±1mm) and 8mm (±1mm), respectively. The resection level did not differ significantly between men and women or between different component sizes. There was a slightly positive correlation between the femoral mechanical and anatomical axis angle and the distance of the distal-lateral condylar resection from the femoral sulcus. The sulcus cut technique can be used to determine the desirable level of the distal femoral resection in TKA. Case series, Level IV.

Can Statistically Determined Prognostic Factors Predict the Long-Term Survival of Patients With Pancreatic Ductal Adenocarcinoma Following Surgical Resection?

The objective of this study were to analyze and describe the clinicopathological characteristics of long-term pancreatic ductal adenocarcinoma survivors and to determine if statistically identified prognostic factors can be used to predict the actual survival. Between January 2000 and December 2007, 537 patients with resectable pancreatic ductal adenocarcinoma underwent surgical resection at a single institute. Medical records were retrospectively reviewed, and 9 patients were excluded. Of the remaining 528, patients who survived for more than 5 years were classified as long-term survivors. The actual 5-year survival rate of all 528 included patients was 15.5% (82 patients; median follow-up period, 82.7 months). Fifty-eight patients (70.7%) were diagnosed with cancers located in the head of pancreas, and the median size was 2.5 cm (range, 0.8-12.0 cm). Three patients had focal involvement noted on the resected surfaces. Poorly differentiated carcinoma (9.8%), lymph node metastasis (32.9%), lymphovascular invasion (25.6%), and perineural invasion (48.8%) were detected. Fifty-five of the 82 long-term survivors whose clinicopathological characteristics included several dismal predictors survived for more than 5 years without recurrence. The long-term survivors identified in this study did not meet the appropriate prognostic criteria. Therefore, there are limitations in the use of statistically determined prognostic factors for estimating in the long term.

Crack formation on resected root surfaces subjected to conventional, ultrasonic, and laser root-end cavity preparation.

The aim of this study was to evaluate cracks on root ends following resection and cavity preparation with a laser and two established techniques. If root canal treatment of a tooth fails, an apicoectomy operation may be indicated. Three millimeters of the root tip is resected and a cavity of similar depth with parallel walls is cut to receive a root-end filling. Sixty extracted human maxillary anterior teeth were used. Their root canals were prepared with rotary instruments, and they were filled with gutta-percha. Twenty teeth were resected with tungsten carbide fissure burs, and their root-end cavities cut with tungsten carbide round burs at a slow speed (Group 1). The other 40 teeth were resected with an Er:YAG laser, and root-end cavities were made with the same laser (Group 2), or with an ultrasonically-powered zirconium nitride coated retrotip (Group 3). The number and types of cracks on the resected surfaces were assessed using a stereomicroscope before and after cavity preparation. Cracking was not significantly different between the more conventional group and the laser groups after resections (p>0.05) or following cavity preparation (p>0.05). In this in vitro study, the laser resection and root-end preparation technique did not influence the number or type of cracks formed on the root surfaces.

Anatomical differences between the resected tibial surface and tibial component in normal Chinese

Objective To obtain the linear parameters of proximal tibia in normal Chinese,and study the anatomical differences between the resected tibial surfaces and tibial baseplates of total knee prostheses.Methods A total of 82 normal Chinese / 135 knees (include 85 male and 50 female knees) was included,with an average age of 47.2 (range,19-82) years.All of the volunteers were scanned by Spiral CT,and the original CT images were stored in the work station (Adw 4.3).Then 3-D models of Chinese normal knees were reconstructed and two parameters were measured through volume reconstruction software,including mediolateral (ML) width and anterioposterior (AP) length.A coordinate system was formed with the mediolateral width as the X-axis and anterioposterior length as the Y-axis.A circle,5 mm in diameter,was used as the maximum coverage criterion.Three contemporary products (A,B,C) were used to analyze the data.From the results,we calculated the coverage percentage of the patients.Results The average ML width and AP length of the proximal tibia section were 78.03±2.92 mm and 50.62±2.46 mm in male,and 69.85±2.70 mm and 46.14±2.61 mm in female,respectively.The average ratio of AP length and ML width (RAP/ML) was 0.649 ±0.032 in male and 0.661± 0.031 in female,respectively.AP length and ML width showed statistical significance between different genders.The RAP/ML was larger in female,and the difference was statistically significant.The average coverage rate of prosthesis A,B and C was 42.55％,44.61％ and 27.41％,respectively.There was no statistically significant difference between prosthesis A and B.However,all of them showed statistical significance with prosthesis C.Conclusion The geometry and anatomy of proximal tibia in Chinese showed significant differences with that in Western.Those characteristic differences should be considered when we use the tibial plateau prosthesis designed by the Westerners. Key words: Tibia; Imaging, three-dimensional; Arthroplasty, replacement, knee

Marginal adaptation of new bioceramic materials and mineral trioxide aggregate: a scanning electron microscopy study.

This study aimed to compare the marginal adaptation of new bioceramic materials, EndoSequence Root Repair Material (ERRM putty and ERRM paste), to that of mineral trioxide aggregate (MTA) as root-end filling materials. Thirty-six extracted human single-rooted teeth were prepared and obturated with gutta-percha and AH-26 sealer. The roots were resected 3 mm from the apex. Root-end cavities were then prepared with an ultrasonic retrotip. The specimens were divided into three groups (n=12) and filled with MTA, ERRM putty or ERRM paste. Epoxy resin replicas from the resected root-end surfaces and longitudinally sectioned roots were fabricated. The gaps at the material/dentin interface were measured using scanning electron microscope (SEM). Transversal, longitudinal, and overall gap sizes were measured for each specimen. The data were analyzed using the Kruskal-Wallis test. In transversal sections, no significant difference was found between MTA, ERRM putty and ERRM paste (P=0.31). However, in longitudinal sections, larger gaps were evident between ERRM paste and dentinal walls compared to MTA and ERRM putty (P=0.002 and P=0.033, respectively). Considering the overall gap size values, the difference between three tested materials was not statistically significant (P=0.17). Within the limits of this study, the marginal adaptation of ERRM paste and putty was comparable to that of MTA. However, ERRM putty might be more suitable for filling the root-end cavities because of its superior adaptation compared to ERRM paste in longitudinal sections.

Defining a stimuli-response relationship in compensatory lung growth following major resection

Major lung resection is a robust model that mimics the consequences of loss-of-functioning lung units. We previously observed in adult canines, following 42% and 58% lung resection, a critical threshold of stimuli intensity for the initiation of compensatory lung growth. To define the range and limits of this stimuli-response relationship, we performed morphometric analysis on the remaining lobes of adult dogs, 2-3 years after surgical removal of ∼ 70% of lung units in the presence or absence of mediastinal shift. Results were expressed as ratios to that in corresponding control lobes. Lobar expansion and extravascular tissue growth (∼ 3.8- and ∼ 2.0-fold of normal, respectively) were heterogeneous; the lobes remaining next to the diaphragm exhibited a greater response. Tissue growth and capillary formation, indexed by double-capillary profiles, increased, regardless of mediastinal shift. Septal collagen fibers increased up to 2.7-fold, suggesting a greater need for structural support. Compared with previous cohorts following less-extensive resection, tissue volume and gas-exchange surface areas increased significantly only in the infracardiac lobe following 42% resection, exceeded two- to threefold in all lobes following 58% resection, and then exhibited diminished gains following ∼ 70% resection. In contrast, alveolar-capillary formation increased with incremental resection without reaching an upper limit. Overall structural regrowth was most vigorous and uniform following 58% resection. The diminishment of gains in tissue growth, following ∼ 70% resection, could reflect excessive or maldistributed mechanical stress that threatens septal integrity. Results also suggest additional independent stimuli of alveolar-capillary formation, possibly related to the postresection augmentation of regional perfusion.

Effect of applied force and blade speed on histopathology of bone during resection by sagittal saw

A sagittal saw is commonly used for resection of bone during joint replacement surgery. During sawing, heat is generated that can lead to an increase in temperature at the resected surface. The aim of this study was to determine the effect of applied thrust force and blade speed on generating heat. The effect of these factors and their interactions on cutting temperature and bone health were investigated with a full factorial Design of Experiments approach for two levels of thrust force, 15N and 30N, and for two levels of blade oscillation rate, 12,000 and 18,000 cycles per minute (cpm). In addition, a preliminary study was conducted to eliminate blade wear as a confounding factor. A custom sawing fixture was used to crosscut samples of fresh bovine cortical bone while temperature in the bone was measured by thermocouple (n=40), followed by measurements of the depth of thermal necrosis by histopathological analysis (n=200). An analysis of variance was used to determine the significance of the factor effects on necrotic depth as evidenced by empty lacunae. Both thrust force and blade speed demonstrated a statistically significant effect on the depth of osteonecrosis (p<0.05), while the interaction of thrust force with blade speed was not significant (p=0.22). The minimum necrotic depth observed was 0.50mm, corresponding to a higher level of force and blade speed (30N, 18,000cpm). Under these conditions, a maximum temperature of 93°C was measured at 0.3mm from the kerf. With a decrease in both thrust force and blade speed (15N, 12,000cpm), the temperature in the bone increased to 109°C, corresponding to a nearly 50% increase in depth of the necrotic zone to 0.74mm. A predictive equation for necrotic depth in terms of thrust force and blade speed was determined through regression analysis and validated by experiment. The histology results imply that an increase in applied thrust force is more effective in reducing the depth of thermal damage to surrounding bone than an increase in blade speed.

Morphometry of the medial tibial plateau in Turkish knees: correlation to the current tibial components of unicompartmental knee arthroplasty.

The objective of this study was to measure the resected surfaces of the tibia in knees of Turkish patients and to compare these measurements with the dimensions of tibial implants in current use. We made measurements of seven different dimensions of the medial tibial plateau at the virtual resection level for unicompartmental knee arthroplasty (UKA) on MRIs of 260 patients and the most commonly used four UKA implants in Turkey. Statistical analysis was performed by using Student's t-test, analysis of variance (ANOVA), chi-square test and Pearson's correlation coefficient by using SPSS software. The anteroposterior and widest mediolateral dimensions of the tibial plateau of Turkish knees were found relatively more approximate to the dimensions of Oxford and Zuk prostheses compared to that of Accuris and Mitus (p<0.001). The distance between the central mediolateral dimension and the widest mediolateral dimension was 2.4 (range: 0-6.3) mm in males and 2.6 (range: 0-6.2) mm in females. The maximum mediolateral dimension was found posterior to the central mediolateral dimension in the majority (202 out of 260) of cases. These findings point towards the asymmetry in the AP halves of the resected medial tibial condyle. Tibial components designed according to anthropometric measurements based on both Western and Asian populations do not perfectly meet the requirements of Turkish population. Designing different UKA prostheses for different populations are required for best fit.

Laser Resection of Lung Tissue: Heat Accumulation from Adjacent Laser Application and How to Cool It Down

Heat accumulation might induce thermal damage of the surrounding lung tissue, especially when multiple lesions are resected in one session. The present study aimed to investigate whether heat accumulates in the immediate vicinity of the resection surface and leads to thermal damage of the lung parenchyma, and what is the most effective cooling strategy in this situation. In normothermic perfused paracardial swine lobes (n = 6), four punctiform laser lesions forming a square were created. Each lesion was lasered at a power of 100 W for 5 seconds. Two test conditions with square sides of either 1.0 or 0.5 cm were compared. Temperatures were recorded immediately after completing the laser procedure in the square center and in the corners using a thermal camera and continued during the cooling process at 10-second intervals until normothermia (37°C). We examined two cooling methods: rinsing with ice-cold (4°C) Ringer solution during the laser procedure (group B, n = 6) or submerging the lung in ice-cold water for 5 seconds immediately after laser application (group C, n = 6). In the control group A (n = 6), there was no cooling. In the 0.5 cm squares, mean temperature in the center immediately after laser application was 103.17 ± 8.56°C, significantly higher than in the corners (76.39 ± 2.87°C, p < 0.05). Normothermia in the quadrant corners was reached after 81 ± 14 and after 108 ± 29 seconds in the centers. Tissue in the square center revealed histological signs of thermic cell damage. In the 1.0 cm squares, mean temperature in the center was 64 ± 5°C, and in the corners was 77 ± 3.1°C (p < 0.05). Normothermia was regained after 93 ± 22 seconds in the center and 120 ± 21 seconds in the corners. Histological examination in the 1.0-quadrant centers revealed no signs of thermic cell damage. Submerging the lobe into ice-cold water lowered the temperature rapidly to under 40°C, and normothermia was regained after 75 ± 1.3 seconds. Laser application to the lung parenchyma causes considerable heat accumulation in closely related lesions. To prevent such cell damage, a distance of at least 1.0 cm between laser targets should be maintained. If no topical cooling method applied, sufficient time for spontaneous tissue cooling before additional laser application should be provided. The most effective cooling strategy against heat accumulation is submerging in ice-cold water for at least 5 seconds.

Heat dissipation after nonanatomical lung resection using a laser is mainly due to emission to the environment: an experimental ex vivo study

Laser-directed resection of lung metastases is performed more frequently in recent years. The energy-loaded laser rays heat up the lung tissue, considerably. It is still unclear which mechanism is more important for tissue heat dissipation: the lung perfusion or the tissue emission. Therefore, we created a special experimental model to investigate the spontaneous heat dissipation after nonanatomical lung resection using a diode-pumped laser with a high output power. Experiments were conducted on paracardiac pig lung lobes (n = 12) freshly dissected at the slaughterhouse. Nonanatomical resection of lung parenchyma was performed without lobe perfusion in group 1 (n = 6), while group 2 (n = 6) was perfused at a physiological pressure of 25 cm H2O at 37 °C with saline via the pulmonary artery. For this, we used a diode-pumped neodymium-doped yttrium aluminum garnet (Nd:YAG) LIMAX® 120 laser (Gebrüder Martin GmbH & Co. KG, Tuttlingen, Germany) with a wavelength of 1,318 nm and a power output of 100 W. Immediately after completing laser resection, the lungs were monitored with an infrared camera (Type IC 120LV; Trotec, Heinsberg, Germany) while allowed to cool down. The resection surface temperature was taken at 10-s intervals and documented in a freeze-frame until a temperature of 37 °C had been reached. The temperature drop per time unit was analyzed in both groups. Immediately after laser resection, the temperature at the lung surface was 84.33 ± 8.08 °C in group 1 and 76.75 ± 5.33 °C in group 2 (p = 0.29). Group 1 attained the final temperature of 37 °C after 182.95 ± 53.76 s, and group 2 after 121.70 ± 16.02 s (p = 0.01). The temperature drop occurred exponentially in both groups. We calculated both groups’ decays using nonlinear regression, which revealed nearly identical courses. The mean time of tissue temperature of >42 °C, as a surrogate marker for tissue damage, was 97.14 ± 26.90 s in group 1 and 65.00 ± 13.78 s in group 2 (p = 0.02). Heat emission to the environment surpasses heat reduction via perfusion in nonanatomically laser-resected lung lobes. In developing a cooling strategy, a topical cooling method would be promising.

HEMORRHAGE PREVENTION AND COMPENSATION IN HEPATIC RESECTION SURGERY

Aim. To improve the results of surgery in patients with focal hepatic diseases using rational surgical tactics, purposeful transfusion therapy and effective hemostatic means. Materials and methods. During the period from 1995 to 2003, 398 patients with focal hepatic diseases were treated. 257 patients (64,6%) underwent hepatic resection including 98 (38,1%) – large hepatic resections (3 segments), 159 (61,9%) – minor hepatic resections. Patients were divided into two groups – the main group ( n =137) and the comparison group ( n =120). In the main group, 54 (39,4%) patients underwent large resections, 83 (60,6%) – minor ones. In the comparison group, 44 (36,7%) had large hepatic resections, 76 (63,3%) – minor ones. In the main group the following means were applied: preoperative autoblood reservation, principle of operation from the vessels, hepatic tissue dissection by means of ultrasonic destructor-aspirator and harmonic Ultracision «Johnson&Johnson» scalpel, Pringle manoeuvre, argonoplasmic coagulation of resected hepatic stump surface, local hemostatic means. In the comparison group, hepatic-duodenal ligament compression, isolation of vasculosecretory elements by resection line using digitoclasy, hepatic stump suturing was used by indications so as to prevent hemorrhage. Results. The volume of intraoperative hemorrhage in the main group reached 1100±20 ml, in the comparison group – 2700±250 ml ( p <0,001). The average number of transfused doses of allogenic blood in the main group was 2,1±0,3, in the comparison group – 12,5±1,3 ( p <0,001). The average volume of previously prepared transfused autoblood in the main group was 0,83±0,1 dose, in the comparison group it was not used. After preoperative autoblood reservation was included into the program, the average volume of transfused allogenic blood decreased from 11,1±1,6 to 1,5±1,1 doses ( p <0,001) in case of large hepatic resections and from 3,6±1,1 doses to 0 – in minor resections ( p <0,001). The postoperative lethality in the main group was 2,2% ( n =3), in the comparison group – 9,2% ( n =11). Conclusion. Introduction of modern equipment into surgical practice for the purpose of performing hepatic parenchyma dissection permits to reduce the volume of hemorrhage and the number of doses of infused donor erythromass. Local hemostatic means applied decrease the risk of developing hemorrhage and biliary excretion from the wound surface of hepatic stump in the postoperative period. The developed system of intraoperative and perioperative safety in hepatic resection surgery allows to reduce the risk of operative intervention, to lower the number of postoperative complications.

Comparison of local tissue damage: monopolar cutter versus Nd:YAG laser for lung parenchyma resection. An experimental study

Lung metastases are non-anatomically resected while sparing as much parenchyma as possible. For this purpose, a few surgeons use the Nd:YAG Laser LIMAX 120, whereas the majority of surgeons use a monopolar cutter like the MAXIUM. The aim of this experimental study was to investigate which instrument causes less lung-tissue damage at the same power output. These experiments were conducted on left lungs (n = 6) taken from freshly slaughtered pigs. The laser and the monopolar cutter were fixed in a hydraulic mover. The laser was focused at a distance of 3 cm to the lung tissue and the monopolar cutter was fixed in pressure-free contact with the lung surface. Both instruments were manoeuvred at a speed of 5, 10 and 20 mm/s in a straight line at an output of 100 watts over the lung surface. The lung lesions that ensued were then examined macro- and microscopically. The same procedures were repeated at a distance of 1 cm creating parallel lesions in order to analyse the lung tissue in between the lesions for thermal damage. In addition, two implanted capsules in the lung tissue simulating a lung nodule were resected with either the laser or the monopolar cutter. The resection surfaces were then examined by magnetic resonance imaging and histology for tissue damage. Finally, we created a 2-cm wide mark on the lung surface to test the resection capacity of both instruments within 1 min. The laser created sharply delineated lesions with a vaporization and coagulation zone without thermal damage of the surrounding lung tissue. With lowering the working speed, each zone was extended. At a working speed of 10 mm/s, the mean vaporization depth using the laser was 1.74 ± 0.1 mm and the mean coagulation depth was 1.55 ± 0.09 mm. At the same working speed, the monopolar cutter demonstrated a greater cutting effect (mean vaporization depth 2.7 ± 0.11 mm; P < 0.001) without leaving much coagulation on the resection surface (mean coagulation depth 1.25 ± 0.1 mm; P = 0.002). In contrast to the laser, the monopolar cutter caused thermal damage of the adjacent lung tissue. The adjacent tissue injury was detected in histological examination as well as in the MRI findings. Adjacent lung tissue after lung metastasectomy using the monopolar cutter was hyper-intensive in T2-weighted MR imaging, indicating a severe tissue damage. No significant changes in signal intensity were observed in T2-weighted imaging of the adjacent lung tissue after using the laser for lung resection. One minute of laser applied at a 100-watt output penetrated a lung surface area of 3.8 ± 0.4 cm(2) compared with 4.8 ± 0.6 cm(2) of surface after application of the monopolar cutter (P = 0.001). The monopolar cutter possesses indeed a greater cutting capacity than the laser, but it also causes more adjacent tissue injury. Thus, laser resection might be preferred for lung metastasectomy.

Endoscopic Treatment of Biliary Fistulas Developing After Liver Resections

Bile leaks are a major cause of mortality and morbidity after liver resections. We prospectively evaluated the safety and efficacy of endoscopic treatment of biliary fistulas developing after liver resections in 15 patients. Fistulas developed after extended right hepatectomy in 4, extended left hepatectomy in 8, and segmentectomy in 3 patients. Median time interval between surgery and endoscopic intervention was 10 days (range, 7 to 35 d). Endoscopic sphincterotomy followed by a nasobiliary drain insertion was the initial treatment. If the fistula persisted after 2 weeks, nasobiliary drain was replaced by a plastic stent. The effect of output (low in 10 and high in 5 patients) and the origin of fistula (stump in 10 and resection surface of the liver in 5 patients) on the time for closure were evaluated. Bile leakage ceased by only nasobiliary drainage catheter placement in 11 patients (73.3%). Plastic stents were inserted in 4 patients. There was a significant correlation between the output of bile leakage and the time needed for fistula closure. Endoscopic treatment methods are effective in patients with bile leaks due to liver resections.

Airtightness of lung parenchyma without a closing suture after atypical resection using the Nd:YAG Laser LIMAX(R) 120

Lung metastases can be non-anatomically resected with a Nd:YAG Laser. It is recommended that the resected lung surface be sealed by slowly resorbable sutures. However, the lung tissue may be restricted by the sutures once it is re-ventilated. Thus, it was analysed whether the lung parenchyma is airtight after laser resection without suturing the defect. The pulmonary artery of unimpaired paracardial lung lobes of freshly slaughtered pigs (mean weight 46 g) was cannulated and rinsed out via a hypotonic saline-heparin solution (5000 IE) until the perfusate was clear of body fluid. The lobular bronchus was connected to an airtight ventilation tube (Fa. VYGON 520 3.5 oral tube) and ventilated pressure-controlled (PEEP + 5 cm H₂O, P₁ = 20 cm H₂O, frequency = 10/min) via a respirator. All lobes were perfused with Ringer solution at 42°C at normothermia and normotonia. In group 1 (n = 8), an atypical peripheral parenchymal resection (average resected surface: 2 × 2 cm(2)) and in group 2 (n = 8), a deep atypical parenchymal resection (average resected surface: 4 × 4 cm(2)) were performed with the Nd:YAG Laser LIMAX 120 (output power at 100 watts). After post-resection ventilation of 15 min, the resection surface was tested for airtightness and burst pressure. All group 1 lobes tested airtight under pressure-controlled ventilation. The mean burst pressure was 34.4 mbar (SD ± 3.2 mbar). Six lobes of group 2 were also completely airtight. The remaining two lobes, however, revealed a serious parenchymal leak (score 3). This was caused by the cross-opening of a segmental bronchus, although the surrounding lung parenchyma was also airtight. The mean burst pressure of these lobes was 31.7 mbar (SD ± 4.08 mbar). There was no significant difference between the two groups (P = 0.12). Peripheral lung defects after Nd:YAG Laser resection might not be sutured, since the laser-induced vaporization of the lung parenchyma seems to be initially airtight. These experimental data warrant confirmation in a controlled clinical study.

Soft coagulation in partial nephrectomy without renorrhaphy: Feasibility of a new technique and early outcomes

To study the feasibility of a new partial nephrectomy technique using soft coagulation without renorrhaphy. Open partial nephrectomy using soft coagulation without renorrhaphy was carried out on 39 consecutive patients with renal tumors. The renal artery was clamped in the initial 23 cases (59%), whereas 16 surgeries (41%) were carried out without clamping. The resected surface of the kidney was coagulated solely by soft coagulation without renorrhaphy. Suturing was used only when the urinary collecting system was opened. The surgical results and perioperative complications were retrospectively evaluated. The mean age of patients was 63.1 years. The mean tumor size was 28.2 mm (range 10-56 mm). The mean RENAL nephrometry score was 8.03 (range 4-10). The mean cold ischemic time (in clamped cases) was 25 min. The mean operative time was 193 min (range 113-310 min), and the mean estimated total blood loss was 172 mL (range 20-530 mL) in all cases. All operations were uneventful, and none required blood transfusion or conversion to nephrectomy. Postoperative complications, such as hemorrhage, urinary fistula formation and requirement of hemodialysis, were not observed. All patients had negative surgical margins, and were free of disease recurrence during the follow-up period (3-49 months). Overall, a remarkable decrease in renal function was not evident at the end of the follow-up period. This new technique using soft coagulation appears to be safe and feasible for partial nephrectomy.

Technique of hepatic arterial anastomosis in living donor pediatric auxiliary partial orthotopic liver transplantation

Technique of hepatic arterial anastomosis in living donor pediatric auxiliary partial orthotopic liver transplantation

Gadoxetate uptake as a possible marker of hepatocyte damage after liver resection-preliminary data

To determine the feasibility of evaluating surgically induced hepatocyte damage using gadoxetate disodium (Gd-EOB-DTPA) as a marker for viable hepatocytes at magnetic resonance imaging (MRI) after liver resection. Fifteen patients were prospectively enrolled in this institutional review board-approved study prior to elective liver resection after informed consent. Three Tesla MRI was performed 3-7 days after surgery. Three-dimensional (3D) T1-weighted (W) volumetric interpolated breath-hold gradient echo (VIBE) sequences covering the liver were acquired before and 20min after Gd-EOB-DTPA administration. The signal-to-noise ratio (SNR) was used to compare the uptake of Gd-EOB-DTPA in healthy liver tissue and in liver tissue adjacent to the resection border applying paired Student's t-test. Correlations with potential influencing factors (blood loss, duration of intervention, age, pre-existing liver diseases, postoperative change of resection surface) were calculated using Pearson's correlation coefficient. Before Gd-EOB-DTPA administration the SNR did not differ significantly (p=0.052) between healthy liver tissue adjacent to untouched liver borders [59.55±25.46 (SD)] and the liver tissue compartment close to the resection surface (63.31±27.24). During the hepatocyte-specific phase, the surgical site showed a significantly (p=0.04) lower SNR (69.44±24.23) compared to the healthy site (78.45±27.71). Dynamic analyses revealed a significantly lower increase (p=0.008) in signal intensity in the healthy tissue compared to the resection border compartment. EOB-DTPA-enhanced MRI may have the potential to be an effective non-invasive tool for detecting hepatocyte damage after liver resection.

ANALYSIS OF THE REGENERATIVE PROCESS OF THE OPTIC TECTUM IN AN ANURAN (XENOPUS LAEVIS DAUDIN) FOLLOWING REMOVAL OF BOTH OPTIC LOBES

SUMMARY Seventy Xenopus laevis Daudin larvae (55 at stage 50 and 15 at stage 52–53, according to NIEUWKOOP & FABER, 1956) were submitted to bilateral ablation of the optic lobes and a study was made on the gradual evolution of the regenerative process from the 10th-90th day after the operation. The results obtained demonstrated that: 1. Regeneration of the optic tectum takes place by means of neural elements originating in the ependymal layer of the mesencephalic body. These cells, after covering the resection surface, multiply actively and, attaching themselves to the internal surface of the primitive pia mater, they migrate dorsally. The formation of a primary tectal lamina can be observed on about the 10th post-operative day. 2. In the early stages of the regenerative process of the optic tectum two factors have been shown to be of fundamental importance, regeneration of the pia mater and the pressure exerted by the rachidian-encephalic fluid. 3. Up to the 10th post-operative day the primary tectal lam...

HINTEGRA Revision Arthroplasty for Failed Total Ankle Prostheses

When a total ankle replacement fails, arthrodesis has been advocated as the treatment of choice. With the availability of a wide spectrum of implants, revision arthroplasty may become a viable alternative. We reviewed a consecutive series of 117 cases (116 patients [fifty-six female and sixty male]; mean age, 55.0 ± 12.0 years) in which a total ankle arthroplasty failed after a mean of 4.3 years and was revised with use of the HINTEGRA three-component total ankle prosthesis. The reason for revision involved the metallic components in sixty ankles (51%), the bone in twenty-eight (24%), the soft tissues in twenty (17%), and infection in nine (8%). The talar component was revised in 104 ankles (89%) and the tibial component, in 106 (91%). Early complications included a fracture of the malleoli in two ankles and a dislocation of the polyethylene insert in one. Seventeen (15%) of the revision arthroplasties required further revision surgery, in most cases for loosening of one or two of the prosthetic components. The mean American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score for the remaining 100 ankles (85%) improved from 44 ± 18 preoperatively to 72 ± 19 (p < 0.01) at the time of the latest follow-up (mean, 6.2 years). The estimated survival of the revision arthroplasties at nine years, with loosening of components as the end point, was 83%. The prevalence of component loosening was higher (p < 0.005) with the use of single-coated hydroxyapatite components (six of twenty-three ankles, 26%) than with double-coated components (five of ninety-four ankles, 5%). The correlation between the extent of bone loss at the resection surface and the prevalence of component failure was weak and not significant. The medium-term results of revision arthroplasty after a failed total ankle arthroplasty were similar to those after primary arthroplasty. The key to success was firm anchorage of the components to primary bone stock. A single hydroxyapatite component coating should no longer be used for revision total ankle arthroplasty.