Machine learning augmented near-infrared spectroscopy: In vivo follow-up of cartilage defects.

OBJECTIVE: To assess the potential of near-infrared spectroscopy (NIRS) for in vivo arthroscopic monitoring of cartilage defects. METHOD: Sharp and blunt cartilage grooves were induced in the radiocarpal and intercarpal joints of Shetland ponies and monitored at baseline (0 weeks) and at three follow-up timepoints (11, 23, and 39 weeks) by measuring near-infrared spectra in vivo at and around the grooves. The animals were sacrificed after 39 weeks and the joints were harvested. Spectra were reacquired ex vivo to ensure reliability of in vivo measurements and for reference analyses. Additionally, cartilage thickness and instantaneous modulus were determined via computed tomography and mechanical testing, respectively. The relationship between the ex vivo spectra and cartilage reference properties was determined using convolutional neural network. RESULTS: In an independent test set, the trained networks yielded significant correlations for cartilage thickness (ρ = 0.473) and instantaneous modulus (ρ = 0.498). These networks were used to predict the reference properties at baseline and at follow-up time points. In the radiocarpal joint, cartilage thickness increased significantly with both groove types after baseline and remained swollen. Additionally, at 39 weeks, a significant difference was observed in cartilage thickness between controls and sharp grooves. For the instantaneous modulus, a significant decrease was observed with both groove types in the radiocarpal joint from baseline to 23 and 39 weeks. CONCLUSION: NIRS combined with machine learning enabled determination of cartilage properties in vivo, thereby providing longitudinal evaluation of post-intervention injury development. Additionally, radiocarpal joints were found more vulnerable to cartilage degeneration after damage than intercarpal joints.

Evaluation of equine articular cartilage degeneration after mechanical impact injury using cationic contrast-enhanced computed tomography.

OBJECTIVE: Cationic agent contrast-enhanced computed tomography (cationic CECT) characterizes articular cartilage ex vivo, however, its capacity to detect post-traumatic injury is unknown. The study objectives were to correlate cationic CECT attenuation with biochemical, mechanical and histological properties of cartilage and morphologic computed tomography (CT) measures of bone, and to determine the ability of cationic CECT to distinguish subtly damaged from normal cartilage in an in vivo equine model. DESIGN: Mechanical impact injury was initiated in equine femoropatellar joints in vivo to establish subtle cartilage degeneration with site-matched controls. Cationic CECT was performed in vivo (clinical) and postmortem (microCT). Articular cartilage was characterized by glycosaminoglycan (GAG) content, biochemical moduli and histological scores. Bone was characterized by volume density (BV/TV) and trabecular number (Tb.N.), thickness (Tb.Th.) and spacing (Tb.Sp.). RESULTS: Cationic CECT attenuation (microCT) of cartilage correlated with GAG (r = 0.74, P < 0.0001), compressive modulus (Eeq) (r = 0.79, P < 0.0001) and safranin-O histological score (r = -0.66, P < 0.0001) of cartilage, and correlated with BV/TV (r = 0.37, P = 0.0005), Tb.N. (r = 0.39, P = 0.0003), Tb.Th. (r = 0.28, P = 0.0095) and Tb.Sp. (r = -0.44, P < 0.0001) of bone. Mean [95% CI] cationic CECT attenuation at the impact site (2215 [1987, 2443] Hounsfield Units [HUs]) was lower than site-matched controls (2836 [2490, 3182] HUs, P = 0.036). Clinical cationic CECT attenuation correlated with GAG (r = 0.23, P = 0.049), Eeq (r = 0.26, P = 0.025) and safranin-O histology score (r = -0.32, P = 0.0046). CONCLUSIONS: Cationic CECT (microCT) reflects articular cartilage properties enabling segregation of subtly degenerated from healthy tissue and also reflects bone morphometric properties on CT. Cationic CECT is capable of characterizing articular cartilage in clinical scanners.

Functional effects of an interpenetrating polymer network on articular cartilage mechanical properties.

OBJECTIVE: Depletion of glycosaminoglycans (GAGs) and degradation of collagen network are early hallmarks of osteoarthritis (OA). Currently, there are no chondroprotective therapies that mitigate the loss of GAGs or effectively restore the collagen network. Recently, a novel polymeric cartilage supplement was described that forms a charged interpenetrating polymer network (IPN) reconstituting the hydrophilic properties of the extracellular matrix (ECM). To investigate the mechanism by which this hydrophilic IPN improves articular cartilage material properties, a finite element (FE) model is used to evaluate the IPN's effect on the fibrillar collagen network, nonfibrillar matrix, and interstitial fluid flow. METHODS: Bovine osteochondral plugs were degraded with chondroitinase ABC to selectively decrease GAG content. Samples were mechanically tested before and after IPN treatment using unconfined testing geometry and stress-relaxation protocol. Every measurement was modeled separately using a fibril-reinforced poroviscoelastic FE model. Measurement replication was achieved by optimizing the following model parameters: initial and strain-dependent fibril network modulus (Ef0, Efε, respectively), nonfibrillar matrix modulus (Enf), initial permeability (k0) and strain-dependent permeability factor (M). RESULTS: Based on the FE model results, treatment of native and GAG depleted cartilage with the hydrophilic IPN increases the ECM stiffness and impedes fluid flow. The IPN did not alter the stiffness of fibrillary network. Cartilage permeability and the strain-dependent permeability factor decreased with increasing IPN w/v%. CONCLUSIONS: The IPN reconstitutes cartilage material properties primarily by augmenting the hydrophilic ECM. This reinforcement of the solid phase also affects the fluid phase reestablishing low permeability.

Highly nonlinear stress-relaxation response of articular cartilage in indentation: Importance of collagen nonlinearity.

Modern fibril-reinforced computational models of articular cartilage can include inhomogeneous tissue composition and structure, and nonlinear mechanical behavior of collagen, proteoglycans and fluid. These models can capture well experimental single step creep and stress-relaxation tests or measurements under small strains in unconfined and confined compression. Yet, it is known that in indentation, especially at high strain velocities, cartilage can express highly nonlinear response. Different fibril reinforced poroelastic and poroviscoelastic models were used to assess measured highly nonlinear stress-relaxation response of rabbit articular cartilage in indentation. Experimentally measured depth-dependent volume fractions of different tissue constituents and their mechanical nonlinearities were taken into account in the models. In particular, the collagen fibril network was modeled using eight separate models that implemented five different constitutive equations to describe the nonlinearity. These consisted of linear elastic, nonlinear viscoelastic and multiple nonlinear elastic representations. The model incorporating the most nonlinearly increasing Young׳s modulus of collagen fibrils as a function of strain captured best the experimental data. Relative difference between the model and experiment was ~3%. Surprisingly, the difference in the peak forces between the experiment and the model with viscoelastic collagen fibrils was almost 20%. Implementation of the measured volume fractions did not improve the ability of the model to capture the measured mechanical data. These results suggest that a highly nonlinear formulation for collagen fibrils is needed to replicate multi-step stress-relaxation response of rabbit articular cartilage in indentation with high strain rates.

Very early osteoarthritis changes sensitively fluid flow properties of articular cartilage.

In this study, fibril-reinforced poroelastic (FRPE) modeling was used for rabbit knee after anterior cruciate ligament transection (ACLT) to assess how the mechanical properties of collagen, proteoglycans, and fluid in articular cartilage change in early osteoarthritis, and how site-specific these changes are. Unilateral ACLT was performed in eight skeletally mature, female New Zealand white rabbits. A separate control (CTRL) group consisted of knee joints of five non-operated rabbits. Animals were sacrificed at four weeks after ACLT and cartilage-on-bone samples from femoral groove, medial and lateral femoral condyles, and tibial plateaus were harvested. A stress-relaxation protocol in indentation geometry was applied and the FRPE model was fitted to the experimental force-time curve by minimizing the mean absolute error between experiment and simulation. The optimized parameters were: fibril network modulus (Ef), representing the collagen network; non-fibrillar matrix modulus (Enf), representing the PG matrix; and permeability (k), representing fluid flow. Permeability was increased significantly in the ACLT group compared to the CTRL group knees at all sites except for the medial tibial plateau. ACLT also caused a decrease in the Ef at all sites except for the medial and lateral tibial plateaus. The Enf of the ACLT group knees was altered only for the lateral femoral condyle. The results of this study suggest that early osteoarthritis primarily affects cartilage permeability and impairs the collagen network stiffness in a site-specific manner. These findings from early osteoarthritis indicate that fluid flow velocity in articular cartilage may change prior to quantifiable structural alterations in the tissue.

Estimation of articular cartilage properties using multivariate analysis of optical coherence tomography signal.

OBJECTIVE: The aim was to investigate the applicability of multivariate analysis of optical coherence tomography (OCT) information for determining structural integrity, composition and mechanical properties of articular cartilage. DESIGN: Equine osteochondral samples (N = 65) were imaged with OCT, and their total attenuation and backscattering coefficients (µt and µb) were measured. Subsequently, the Mankin score, optical density (OD) describing the fixed charge density, light absorbance in amide I region (Aamide), collagen orientation, permeability, fibril network modulus (Ef) and non-fibrillar matrix modulus (Em) of the samples were determined. Partial least squares (PLS) regression model was calculated to predict tissue properties from the OCT signals of the samples. RESULTS: Significant correlations between the measured and predicted mean collagen orientation (R(2) = 0.75, P < 0.0001), permeability (R(2) = 0.74, P < 0.0001), mean OD (R(2) = 0.73, P < 0.0001), Mankin scores (R(2) = 0.70, P < 0.0001), Em (R(2) = 0.50, P < 0.0001), Ef (R(2) = 0.42, P < 0.0001), and Aamide (R(2) = 0.43, P < 0.0001) were obtained. Significant correlation was also found between µb and Ef (ρ = 0.280, P = 0.03), but not between µt and any of the determined properties of articular cartilage (P > 0.05). CONCLUSION: Multivariate analysis of OCT signal provided good estimates for tissue structure, composition and mechanical properties. This technique may significantly enhance OCT evaluation of articular cartilage integrity, and could be applied, for example, in delineation of degenerated areas around cartilage injuries during arthroscopic repair surgery.

Characterization of site-specific biomechanical properties of human meniscus-Importance of collagen and fluid on mechanical nonlinearities.

Meniscus adapts to joint loads by depth- and site-specific variations in its composition and structure. However, site-specific mechanical characteristics of intact meniscus under compression are poorly known. In particular, mechanical nonlinearities caused by different meniscal constituents (collagen and fluid) are not known. In the current study, in situ indentation testing was conducted to determine site-specific elastic, viscoelastic and poroelastic properties of intact human menisci. Lateral and medial menisci (n=26) were harvested from the left knee joint of 13 human cadavers. Indentation tests, using stress-relaxation and dynamic (sinusoidal) loading protocols, were conducted for menisci at different sites (anterior, middle, posterior, n=78). Sample- and site-specific axisymmetric finite element models with fibril-reinforced poroelastic properties were fitted to the corresponding stress-relaxation curves to determine the mechanical parameters. Elastic moduli, especially the instantaneous and dynamic moduli, showed site-specific variation only in the medial meniscus (p<0.05 between the sites). The instantaneous and dynamic elastic moduli of the anterior horn were significantly (p<0.05) greater in the medial than lateral meniscus. The phase angle showed no statistically significant variation between the sites (p>0.05). The values for the strain-dependent fibril network modulus (nonlinear behaviour of collagen) were significantly different (p<0.05) between all sites in the medial menisci. Additionally, there was a significant difference (p<0.01) in the strain-dependent fibril network modulus between the lateral and medial anterior horns. The initial permeability was significantly different (p<0.05) in the medial meniscus only between the middle and posterior sites. For the strain-dependent permeability coefficient, only anterior and middle sites showed a significant difference (p<0.05) in the medial meniscus. This parameter demonstrated a significant difference (p<0.05) between lateral and medial menisci at the anterior horns. Our results reveal that under in situ indentation loading, medial meniscus shows more site-dependent variation in the mechanical properties as compared to lateral meniscus. In particular, anterior horn of medial meniscus was the stiffest and showed the most nonlinear mechanical behaviour. The nonlinearity was related to both collagen fibrils and fluid.

Alterations in subchondral bone plate, trabecular bone and articular cartilage properties of rabbit femoral condyles at 4 weeks after anterior cruciate ligament transection.

OBJECTIVE: To quantify early osteoarthritic-like changes in the structure and volume of subchondral bone plate and trabecular bone and properties of articular cartilage in a rabbit model of osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT). METHODS: Left knee joints from eight skeletally mature New Zealand white rabbits underwent ACLT surgery, while the contralateral (CTRL) right knee joints were left unoperated. Femoral condyles were harvested 4 weeks after ACLT. Micro-computed tomography imaging was applied to evaluate the structural properties of subchondral bone plate and trabecular bone. Additionally, biomechanical properties, structure and composition of articular cartilage were assessed. RESULTS: As a result of ACLT, significant thinning of the subchondral bone plate (P < 0.05) was accompanied by significantly reduced trabecular bone volume fraction and trabecular thickness in the medial femoral condyle compartment (P < 0.05), while no changes were observed in the lateral compartment. In both lateral and medial femoral condyles, the equilibrium modulus and superficial zone proteoglycan (PG) content were significantly lower in ACLT than CTRL joint cartilage (P < 0.05). Significant alterations in the collagen orientation angle extended substantially deeper into cartilage from the ACLT joints in the lateral femoral condyle relative to the medial condyle compartment (P < 0.05). CONCLUSIONS: In this model of early OA, significant changes in volume and microstructure of subchondral bone plate and trabecular bone were detected only in the femoral medial condyle, while alterations in articular cartilage properties were more severe in the lateral compartment. The former finding may be associated with reduced joint loading in the medial compartment due to ACLT, while the latter finding reflects early osteoarthritic changes in the lateral compartment.

Site-dependent changes in structure and function of lapine articular cartilage 4 weeks after anterior cruciate ligament transection.

OBJECTIVE: The aim of this study was to investigate the site-dependent changes in the structure and function of articular cartilage in the lapine knee joint at a very early stage of osteoarthritis (OA), created experimentally by anterior cruciate ligament transection (ACLT). METHODS: Unilateral ACLT was performed in eight mature New Zealand white rabbits. ACL transected and contralateral (C-L) joints were prepared for analysis at 4 weeks after ACLT. Three rabbits with intact joints were used as a control group (CNTRL). Femoral groove, medial and lateral femoral condyles, and tibial plateaus were harvested and used in the analysis. Biomechanical tests, microscopy and spectroscopy were used to determine the biomechanical properties, composition and structure of the samples. A linear mixed model was chosen for statistical comparisons between the groups. RESULTS: As a result of ACLT, the equilibrium and dynamic moduli were decreased primarily in the femoral condyle cartilage. Up to three times lower moduli (P < 0.05) were observed in the ACLT group compared to the control group. Significant (P < 0.05) proteoglycan (PG) loss in the ACLT joint cartilage was observed up to a depth of 20-30% from the cartilage surface in femoral condyles, while significant PG loss was confined to more superficial regions in tibial plateaus and femoral groove. The collagen orientation angle was increased (P < 0.05) up to a cartilage depth of 60% by ACLT in the lateral femoral condyle, while smaller effects, but still significant, were observed at other locations. The collagen content was increased (P < 0.05) in the middle and deep zones of the ACLT group compared to the control group samples, especially in the lateral femoral condyle. CONCLUSION: Femoral condyle cartilage experienced the greatest structural and mechanical alterations in very early OA, as produced by ACLT. Degenerative alterations were observed especially in the superficial collagen fiber organization and PG content, while the collagen content was increased in the deep tissue of femoral condyle cartilage. The current findings provide novel information of the early stages of OA in different locations of the knee joint.

Structure-function relationships in osteoarthritic human hip joint articular cartilage.

OBJECTIVES: It is currently poorly known how different structural and compositional components in human articular cartilage are related to their specific functional properties at different stages of osteoarthritis (OA). The objective of this study was to characterize the structure-function relationships of articular cartilage obtained from osteoarthritic human hip joints. METHODS: Articular cartilage samples with their subchondral bone (n = 15) were harvested during hip replacement surgeries from human femoral necks. Stress-relaxation tests, Mankin scoring, spectroscopic and microscopic methods were used to determine the biomechanical properties, OA grade, and the composition and structure of the samples. In order to obtain the mechanical material parameters for the samples, a fibril-reinforced poroviscoelastic model was fitted to the experimental data obtained from the stress-relaxation experiments. RESULTS: The strain-dependent collagen network modulus (E(f)(ε)) and the collagen orientation angle exhibited a negative linear correlation (r = -0.65, P < 0.01), while the permeability strain-dependency factor (M) and the collagen content exhibited a positive linear correlation (r = 0.56, P < 0.05). The nonfibrillar matrix modulus (E(nf)) also exhibited a positive linear correlation with the proteoglycan content (r = 0.54, P < 0.05). CONCLUSION: The study suggests that increased collagen orientation angle during OA primarily impairs the collagen network and the tensile stiffness of cartilage in a strain-dependent manner, while the decreased collagen content in OA facilitates fluid flow out of the tissue especially at high compressive strains. Thus, the results provide interesting and important information of the structure-function relationships of human hip joint cartilage and mechanisms during the progression of OA.

Stoma care problems after stoma surgery in Northern Finland.

BACKGROUND AND AIMS: Stoma-related complications and problems in stoma care are common after gastrointestinal surgery requiring the construction of a stoma. The frequency and types of such complications and problems were evaluated in a patient cohort operated on in Oulu University Hospital. MATERIAL AND METHODS: A detailed questionnaire concerning clinical problems and stoma care was mailed to 163 stoma patients operated on during the years from 1995 to 2001 in Oulu University Hospital. One hundred and nineteen patients (70 percent) answered the questions adequately. The clinical variables concerning stoma complications and the patients' symptoms, problems with stoma care and adaptation to the situation were recorded. Special attention was paid to the patients' general wellbeing and social problems. RESULTS: Thirty-five patients (30%) had stoma complications, most commonly parastomal hernias (18 cases). Patients with an ileostomy had more difficulties with stoma handling more often than the patients with a colostomy. Seventy-eight patients (66%) were well adapted to their stoma, including 49 (72%) of the patients with a colostomy and 25 (56%) of the patients with an ileostomy. Of the 41 non-adapted patients, 12 did not accept their altered body image, ten had problems in social life and nine had difficulties because of faecal leakage. The quality of life analysis of 114 patients showed that their physical condition was better than before the operation in 55 cases (48%), unchanged in 16 (14%) and worse in 43 (38%). General mental health was better than before the operation in 52 cases (46%), unchanged in 23 (20%) and worse in 39 (34%) patients. Social functioning had improved after stoma surgery in 38 cases (34%), remained unchanged in 27 (24%) and deteriorated in 46 (42%) patients after stoma surgery. Patients with a colostomy reported worse subjective physical condition, mental health and social functioning than the patients with an ileostomy. CONCLUSIONS: Two-thirds of the patients had adapted to their stoma. The patients with an ileostomy had difficulties in stoma handling and the patients with a colostomy reported their physical, mental and social wellbeing to be affected.

Survival after operations for colorectal cancer in patients aged 75 years or over.

OBJECTIVE: To define factors that predict mortality and survival in patients with colorectal cancer who are aged 75 or over. DESIGN: Retrospective study. SETTING: University hospital, Finland. SUBJECTS: 231 patients aged 75 or over who were admitted to hospital with colorectal cancer during the 14-year period 1980-93. MAIN OUTCOME MEASURES: Morbidity, mortality, recurrence, and survival. RESULTS: In-hospital mortality after any kind of operation was 8/211 (4%), and 8/175 (5%) of those who had their tumours resected. Morbidity was 35/175 (20%). Factors associated with mortality were weight loss, Dukes'stage, extent of resection, and type of operation. Overall 5-year survival was 28%, overall 10-year survival was 4%, and median survival was 33 months (range 0-150). Survival was most closely related to Duke's stage, extent of resection, and recurrent disease on univariate analysis, but multivariate analysis identified only mode of recurrence (p < 0.0001), recurrent disease (p < 0.004), and extent of resection (p < 0.009) as independent predictors of survival. The recurrence rate after radical resection was 49/141 (35%) and the median disease-free interval was 10 months (range 4-64). Mortality after resection for recurrent cancer was 3/17 (18%) and morbidity 5/17 (29%). CONCLUSION: Age alone is not a risk factor for postoperative mortality or a predictor of long-term survival. Low mortality and acceptable long-term survival can be achieved in patients aged 75 or over if those with extensive distant metastases, and those whose general condition is too poor to stand a major operation, are treated conservatively.

Bowel preparation with oral polyethylene glycol electrolyte solution vs. no preparation in elective open colorectal surgery: prospective, randomized study.

PURPOSE: Efficient mechanical bowel preparation has been regarded as essential in preventing postoperative complications of colorectal surgery, but the necessity of bowel cleansing has been disputed recently. The aim of this study was to evaluate the outcome of elective colorectal surgery in patients with or without bowel preparation. METHODS: Altogether, 267 consecutive adult patients admitted for elective open colorectal surgery were randomly assigned either to the bowel preparation group with oral polyethylene glycol electrolyte solution (138 patients) or no preparation group (129 patients). Patients who were unable to drink polyethylene glycol electrolyte solution, those who had had bowel preparation within the previous week, and patients not needing opening of the bowel were excluded. Routine colorectal surgery was undertaken, and infectious and other complications were registered daily. Late complications were checked up one to two months after surgery. RESULTS: No deaths were recorded, and 76 percent of the patients in the polyethylene glycol electrolyte solution group and 81 percent in the unprepared group recovered without complication. Anastomotic leaks occurred in 4 percent of the polyethylene glycol electrolyte solution patients and in 2 percent of the other cases, and other surgical site infections occurred in 6 and 5 percent, respectively. None of the differences was statistically significant. There was no difference in restoration of bowel function. The median postoperative stay was eight days in both groups. CONCLUSIONS: Preoperative bowel preparation seems to offer no benefit in elective open colorectal surgery.

Survival after surgery for gastric cancer in patients over 70 years of age.

BACKGROUND AND AIMS: The increase of the elderly population in western societies will result in a considerable increase of gastric cancer patients older than 70 years requiring surgery. However, higher postoperative morbidity and mortality rates after major surgery in the elderly are well recognized. The aim of this study was to evaluate the risk factors of mortality and predictors of survival in elderly patients with gastric cancer. METHODOLOGY: We reviewed the data of the 165 patients evaluated for gastric cancer surgery in the Oulu University Hospital from January 1985 till December 1994 and made a computer analysis. RESULTS: Postoperative mortality was 12% both after all laparotomies and after all resections, and 6% after radical resections. Mortality after radical resection did not associate significantly with any clinical variable but morbidity was associated with the number of coexistent diseases. The median and cumulative 5-year survivals after radical resections were 40 months and 38%. Survival was closely related to diagnostic delay, preoperative loss of weight, two or more coexistent disease, location of tumor, and recurrence in univariate analysis, but multivariate analysis showed only preoperative weight loss and recurrent disease to be independent predictors of survival. CONCLUSIONS: Age alone is not a risk factor for postoperative mortality or a predictor of survival among elderly patients with gastric cancer. Early detection of malignancy and careful preoperative evaluation of the patients referred for resection are needed to improve survival.

Corrosion injury of the upper gastrointestinal tract after swallowing strong alkali.

OBJECTIVE: To review our experience of 9 patients who had attempted suicide by swallowing alkaline substances. DESIGN: Retrospective study. SETTING: Two university hospitals, Finland. PATIENTS: During the years 1987-1996. 9 patients who had swallowed more than 100 ml of strong alkali. RESULTS: 2 patients with oesophagorespiratory fistulas of the four with third degree injuries died in hospital, the first died of overwhelming sepsis and the second of multiple organ failure. The other two survived emergency staged resection and subsequent reconstruction. Delay between swallowing the alkali and the initial operation, and development of oesophagorespiratory fistulas were the most important predictors of death. Four patients with second degree injuries underwent oesophageal resection and reconstruction after they had developed oesophageal strictures. Two of these six survivors developed anastomotic strictures after reconstruction, both of which necessitated repeated oesophageal dilatations. One patient with a first degree injury was treated conservatively. CONCLUSIONS: An early and aggressive approach to severe third degree corrosive injuries of the upper gastrointestinal tract is needed to resect all necrotic tissue and to make it possible to do a successful reconstruction later. The development of oesophagorespiratory fistulas requires immediate attention, whereas first and second degree injuries can be treated after the patient has been stabilized.

Percutaneous cholecystostomy in acute cholecystitis in high-risk patients: an analysis of 69 patients.

BACKGROUND: Optimal treatment of acute cholecystitis in high-risk patients with acute cholecystitis continues to be a difficult therapeutic problem. With the development of more advanced radiological imaging techniques, percutaneous cholecystostomy (PCS) has been presented as an effective treatment alternative in critically ill patients. This paper reports our experiences of percutaneous cholecystostomy in the treatment of acute cholecystitis in a well defined high-risk patient group. METHODS: The data concerning 69 high-risk patients with acute cholecystitis treated by percutaneous cholecystostomy in Oulu University Hospital and Kokkola Central Hospital were analyzed. RESULTS: Ultrasound showed gallbladder stones in 71% (49/69) of the patients and 29% of them presented with acalculous cholecystitis. After PCS, pain diminished in 94% (61/65), fever in 90% (35/39), CRP values in 87% (53/61) and leucocyte count in 84% (46/55) of the patients. Before PCS, the CRP value was 132+/-106 mg/l and after PCS 79+/-73 mg/l (P = 0.001) and corresponding leucocyte counts were 14.7+/-5.0 and 9.3+/-3.2 (P = 0.001), respectively. The antegrade cholecystocholangiography was performed in 29 patients after PCS, and common bile duct stones were detected in 8 patients; these stones were treated by endoscopic papillotomy. Complications after PCS occurred in 17 patients (26%), but only two patients required emergency laparotomy. Mortality was 19% (13/69). Acute cholecystitis alone was the cause of death in only three patients. Mostly, fatal outcome was caused by the serious underlying diseases. CONCLUSION: According to our results, PCS should be the method of choice in high-risk patients with acute cholecystitis.

Analysis of late stomal complications following ostomy surgery.

BACKGROUND AND AIMS: This study was aimed to evaluate the late complications of ostomy surgery in a strictly followed patient population of a university hospital. MATERIAL AND METHODS: An actuarial analysis of the complications of 156 patients with permanent ostomies using the life-table method was performed. RESULTS: The crude and actuarial risks of late stomal complications in 156 patients after a mean follow-up of 8 years were 39 per cent and 59 per cent. The cumulative risk of complications did not differ between the stoma types. Paracolostomy hernia was the most common complication of the colostomy, 27 per cent, retraction of ileostomy, 24 per cent, and intestinal obstruction of urostomy, 28 per cent. Mesenteric fixation was here associated with a lower chance of prolapse (P < 0.025), but the closure of lateral space did not reduce the risk of intestinal obstruction. Skin irritation was more common after a creation of ileostomy than after other stoma creations (P < 0.001). The revisional surgery rate was lower following colostomy than following other stoma formations (P < 0.034). Adaptation to the stoma had occurred in 74% of the patients, but 8 per cent of the patients had intractable symptoms at the time of the analysis. CONCLUSION: Ostomy surgery involves a high rate of late complications and there is a small but important subgroup of patients whose quality of life is seriously affected.

Corrosive oesophageal injury. A study of four cases.

BACKGROUND AND AIMS: The ingestion of a corrosive agent including strong alkaline material causes serious caustic damage to the upper gastrointestinal tract. We describe four cases in patients who had ingested alkaline substances. MATERIAL AND METHODS: During the years 1992-1996, four patients who had ingested strong alkali were treated in the Oulu University Hospital. The patients were reviewed retrospectively. RESULTS: In one case a third-degree, in two cases a second-degree and in one case a first-degree injury developed in the oesophagus. The patient with first-degree injury was treated with repeated endoscopic dilatations and he refused any more aggressive surgical therapy. The patients with more severe injuries were operated, on all with good end results. CONCLUSION: Aggressive surgical treatment of severe corrosive injuries involving the upper gastrointestinal tract is recommended.

Metachronous cecal and sigmoid volvulus.

BACKGROUND AND AIMS: Metachronous cecal and sigmoid volvulus is very rare. MATERIAL AND METHODS: A case report. RESULTS AND CONCLUSION: Two different volvuli necessitated three operations. Cecal volvulus was treated by caecostomy and sigmoid volvulus by detorsion three years later. Sigmoid volvulus recurred after simple operative detorsion, but the patient recovered without complications after a mesocolosplasty. We recommend operative treatment when recurrent colonic volvulus is suspected, and resection is preferable in medically fit patients.