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PubMed1996

An experimental assessment of the risk of compartment syndrome during knee arthroscopy.

The purpose of this study was to objectively evaluate the risk of compartment syndrome as a complication during arthroscopy, particularly with the use of mechanical infusion systems. Little experimental data are available. This study shows that when elevated compartment pressures occur, extravasated fluid dissipates quickly, minimizing the risk of compartment syndrome and subsequent neuromuscular damage. Twelve live pig hind limbs (six swine) were used. Three additional limbs were used as shams. After anesthesia and portal placement for mechanical fluid infusion, two standardized capsulotomies were created to allow free extravasation of fluid. We dynamically monitored intraarticular pressure, and intracompartmental pressure in the anterior (leg), deep posterior (leg), and quadriceps (thigh) compartments. Nerve conduction studies were performed on the tibial and peroneal nerves. Data collection began at the onset of fluid infusion and continued after infusion ceased until elevated compartment pressures fell below 20 mm Hg. There were two study variables: intraarticular pressure (100, 150, or 200 mm Hg) and time of fluid ingress (30, 60, or 90 minutes). Following this, the swine were evaluated serially for 13 to 16 days. Repeat nerve conduction studies, muscle biopsies (in the three previously mentioned compartments), and electromyography were performed 13 to 16 days following the operation. Maximum compartment pressures during fluid infusion averaged 78.75 mm Hg. Significant variability existed when comparing the interrelationships of infusion time, maximum compartment pressures, time of resolution of elevated pressures, and intraarticular pressures. Most importantly, elevated compartment pressures resolved quickly (mean, 25.5 minutes; range, 0 to 100 minutes; n = 36 compartments) when stopping fluid infusion. Nerve conduction studies were normal on all postoperative studies. Electromyographic (EMG) analysis showed normal study results in the biceps, gracilis, abductor digiti quinti, and adductor digiti segundi. Although EMG analysis of the tibialis anterior and extensor digitorum brevis showed 1+ fibrillation (1+ to 4+ scale), this was seen in sham studies with tourniquet alone (no fluid infusion). Muscle biopsies were without evidence of myonecrosis. Finally, 5 of 6 swine ambulated without difficulty on the first postoperative day, whereas 1 swine limped for 2 days. All swine were normal by the 3rd postoperative day and also at the end of the study. These data show that in this model, the risk of developing sequela from compartment syndrome during arthroscopy is minimal, even when there exists significant fluid extravasation and elevated compartment pressures.

Animals↗

PubMed1998

Anatomic investigation of the deep posterior compartment of the leg.

The purpose of this study is to critically investigate the anatomy of the deep posterior compartment of the leg. Specifically, the relationship of the deep posterior compartment to the superficial posterior compartment and their insertion onto the posteromedial border of the tibia are assessed. Cross-sectioning of 10 fresh-frozen cadaver legs was performed at 2-cm increments. The inferior surface of each section was photographed. The photographs were visually analyzed, and the fascial separation between the posterior compartments along with their relationship to the posteromedial border of the tibia were recorded for each specimen. Magnetic resonance images in the axial plane of 10 healthy, normal volunteers' lower extremities at 2-cm increments were obtained and analyzed. All specimens and images demonstrated that the medial fascial attachment of the deep posterior compartment was along the posteromedial aspect of the tibia in the proximal third of the leg and was not superficially accessible. In the proximal third of the leg, the superficial posterior compartment fascial attachment overlapped the deep posterior compartment by inserting medial and anterior to the deep posterior compartment fascial attachment. In the middle and distal thirds of the leg, the medial fascial attachment of the deep posterior compartment shifted medially and anteriorly, making the deep posterior compartment superficially accessible. The surgeon must appreciate the change in the anatomic relationships along the medial side of the leg while performing double-incision four-compartment fasciotomy release to obtain a complete release of the muscular portion of the deep posterior compartment.

Cadaver↗

PubMed1983

The extraneuronal compartments for the distribution of isoprenaline in the rat heart.

The distribution of 3H-isoprenaline in the perfused rat heart was re-examined. After initial loading with 3H-isoprenaline hearts were washed out with amine-free solution; the efflux curves were subjected to the peeling technique, and half times for efflux and compartment sizes were determined. In contrast to earlier reports from his department (Bönisch et al. 1974;l Bönisch 1978), 3H-isoprenaline was found to distribute mainly into one extra-neuronal compartment, irrespective of whether COMT was intact or inhibited (by the presence of U-0521). It was also not influenced by pretreatment of the animals with reserpine. This type of distribution was influenced neither by the concentration of isoprenaline nor by the duration of the loading of the tissue with the amine. The one major extra-neuronal distribution compartment of 3H-isoprenaline has the characteristics of the "old" compartment III: it has a relatively short half time for the efflux of 3H-isoprenaline and it has a high activity of COMT. Moreover, corticosterone inhibits the inward and outward flux of 3H-isoprenaline into and from compartment III. The Ki for the inhibition by corticosterone of the efflux of 3H-isoprenaline (2 mumol/l) is very similar to the Ki for impairment of uptake2 (determined by Bönisch 1978). Apart from the major distribution compartment III, two minor distribution compartments were detected: On the one hand, experiments with hearts which had an intact COMT revealed that a minor distribution compartment IV (characterized by a long half time for efflux and by an absence of COMT activity) may exist, although its magnitude does not exceed one tenth of the former compartment IV. In addition, part of the quickly equilibrating (and rather small) compartment II was corticosterone-sensitive. When the results of Azevedo et al. (1983 are considered together with the present results, compartment III appears to represent the uptake of 3H-isoprenaline into myocardial cells, while it is likely that radioactivity accumulated in the smooth muscle of blood vessels may constitute the corticosterone-sensitive part of compartment II.

Animals↗

PubMed2007

A randomized controlled trial comparing a fascia iliaca compartment nerve block to a traditional systemic analgesic for femur fractures in a pediatric emergency department.

STUDY OBJECTIVE: We determine whether a fascia iliaca compartment nerve block can provide superior pain management compared with intravenous morphine sulfate for the initial pain management of femur fracture patients presenting to a pediatric emergency department. The primary outcome measured is pain scores; a difference of 15% in scores assessed at 30 minutes from the study's baseline pain management is considered clinically meaningful. Secondary outcomes include the duration of analgesia, the need for additional medications, adverse events, nerve block complications, and satisfaction scores. METHODS: This was a prospective, randomized, unblinded, controlled trial conducted on children aged 15 months to 18 years with acute femur fractures, presenting to a free-standing, tertiary care children's hospital. Patients were randomized to receive intravenous morphine sulfate or a fascia iliaca compartment nerve block using ropivacaine (Naropin). Pain scores (Children's Hospital of Eastern Ontario Pain Scale [CHEOPS]; Face, Legs, Activity, Cry and Consolability Pain Scale; Faces Pain Scale) were recorded at initial analgesic administration (baseline), at 5, 10, 15, 30, and 60 minutes, and then hourly up to 6 hours from baseline by trained nursing observers and research assistants. RESULTS: Fifty-five patients, 26 in the fascia iliaca compartment nerve block group and 29 in the morphine sulfate group, ranged in age from 16 months to 15 years (median 5.7 years). Baseline mean CHEOPS scores were similar: 9.4 fascia iliaca compartment nerve block and 9.5 morphine sulfate. Mean CHEOPS scores at 30 minutes after initial treatment were 5.87 for fascia iliaca compartment nerve block and 7.54 for morphine sulfate, with a difference of 1.67, which corresponds to an 18% (95% confidence interval [CI] 8% to 27%) difference in pain reduction between the 2 groups, according to the average baseline score of 9.45. Similar lower pain scores were observed in the fascia iliaca compartment nerve block group as early as 10 minutes from baseline and throughout the 6-hour duration of the study. In comparing the entire 6-hour CHEOPS pain scores, patients who received a fascia iliaca compartment nerve block showed lower scores by approximately 15% (95% CI 6% to 24%) compared to patients who received morphine sulfate. Median duration of analgesia was longer in the fascia iliaca compartment nerve block group compared with that in the morphine sulfate group (313 minutes [95% CI 154 to 360 minutes] versus 60 minutes [95% CI 10 to 255 minutes]). Fewer additional medications were given to patients who received the fascia iliaca compartment nerve block. No complications from the nerve block occurred. Satisfaction scores were higher with the fascia iliaca compartment nerve block among the medical staff. CONCLUSION: Fascia iliaca compartment nerve block provided clinically superior pain management compared with intravenous morphine sulfate at 30 minutes from baseline and throughout the initial 6 hours of medical treatment of children 16 months to 15 years who had isolated acute femur fractures. The results of this study, however, may be inflated by the nonblinding of the pain observers. Despite this potential bias, the fascia iliaca compartment nerve block should be considered as a valuable procedure in managing the pain commonly observed in these injured children.

Adolescent↗

PubMed1993

Cytoarchitecture of size-excluding compartments in living cells.

By fluorescence ratio imaging of large and small inert tracer particles in living cells, we have previously shown that particles 24 nm in radius are excluded from otherwise uncharacterized compartments in the distal and perinuclear cytoplasm (Luby-Phelps, K. and Taylor, D.L., 1988. Cell Motil. Cytoskel. 10, 28-37). In this study we examined the cytoarchitecture of these compartments. Whole-mount TEM showed that distal size-excluding compartments were devoid of membrane-bounded organelles and were filled with a dense cytomatrix consisting of numerous, long bundles of thin filaments interconnected by a more random meshwork of short thin filaments. The mean diameter of void spaces in the cytomatrix of distal excluding compartments was 31 nm, compared to 53 nm in adjacent non-excluding domains. The height of the distal excluding compartments was generally < or = 50% of the height in the adjacent non-excluding compartment. An electron-dense structure having the same projected outline as the perinuclear size-excluding compartment was visible by whole-mount TEM, but the cells were too thick and osmiophilic in this region to resolve any detail. Immunofluorescence localization of cytoskeletal proteins in distal excluding compartments indicated the presence of filament bundles containing F-actin nonmuscle filamin (ABP280) and alpha-actinin. F-actin and ABP280, but not alpha-actinin, were found also in between these filament bundles. Microtubules and vimentin generally were rare or absent from distal excluding domains. Staining of living cells with DMB-ceramide revealed that the perinuclear size-excluding compartment consisted of a compact, juxtanuclear domain coinciding with the trans-Golgi, surrounded by a more diffuse domain coinciding with a perinuclear concentration of endoplasmic reticulum. Intense immunofluorescence staining for vimentin was also observed in the perinuclear size-excluding compartment. We propose that the most likely mechanism for exclusion from distal compartments is molecular sieving by a meshwork of actin filament bundles interconnected by an F-actin/ABP280 gel network, while exclusion from the perinuclear compartment may be due to close apposition of cisternae in the trans-Golgi and a network or basket of vimentin filaments in the centrosomal region of the cell.

3T3 Cells↗

PubMed2002

Kinetic profiles by topographic compartments in muscle-invasive transitional cell carcinomas of the bladder: role of TP53 and NF1 genes.

We evaluated 71 muscle-invasive transitional cell carcinomas (TCCs) of the bladder by tumor compartments. Kinetic parameters included mitotic figure counting, Ki-67 index, proliferation rate (DNA slide cytometry), and apoptotic index (in situ end labeling [ISEL] of fragmented DNA using digoxigenin-labeled deoxyuridine triphosphate and Escherichia coli DNA polymerase [Klenow fragment]). At least 50 high-power fields per compartment were screened from the same tumor areas; results are expressed as percentage of positive neoplastic cells. Mean and SD were compared by tumor compartment. DNA was extracted from microdissected samples (superficial and deep) and used for microsatellite analysis of TP53 and NF1 by polymerase chain reaction-denaturing gradient gel electrophoresis. Significantly higher marker scores were revealed in the superficial compartment than in the deep compartment. An ISEL index of less than 1% was revealed in 63% (45/71) of superficial compartments and 86% (61/71) of deep compartments. Isolated NF1 alterations were observed mainly in superficial compartments, whereas isolated TP53 abnormalities were present in deep compartments. Lower proliferation and down-regulation of apoptosis define kinetically the deep compartment of muscle-invasive TCC of the bladder and correlate with the topographic heterogeneity, NF1-defective in superficial compartments and TP53-defective in deep compartments.

Carcinoma, Transitional Cell↗

PubMed1999

Parabolic quantitative structure-activity relationships and photodynamic therapy: application of a three-compartment model with clearance to the in vivo quantitative structure-activity relationships of a congeneric series of pyropheophorbide derivatives used as photosensitizers for photodynamic therapy.

An open three-compartment pharmacokinetic model was applied to the in vivo quantitative structure-activity relationship (QSAR) data of a homologous series of pyropheophorbide photosensitizers for photodynamic therapy (PDT). The physical model was a lipid compartment sandwiched between two identical aqueous compartments. The first compartment was assumed to clear irreversibly at a rate K0. The measured octanol-water partition coefficients, P(i) (where i is the number of carbons in the alkyl chain) and the clearance rate K0 determined the clearance kinetics of the drugs. Solving the coupled differential equations of the three-compartment model produced clearance kinetics for each of the sensitizers in each of the compartments. The third compartment was found to contain the target of PDT. This series of compounds is quite lipophilic. Therefore these drugs are found mainly in the second compartment. The drug level in the third compartment represents a small fraction of the tissue level and is thus not accessible to direct measurement by extraction. The second compartment of the model accurately predicted the clearance from the serum of mice of the hexyl ether of pyropheophorbide a, one member of this series of compounds. The diffusion and clearance rate constants were those found by fitting the pharmacokinetics of the third compartment to the QSAR data. This result validated the magnitude and mechanistic significance of the rate constants used to model the QSAR data. The PDT response to dose theory was applied to the kinetic behavior of the target compartment drug concentration. This produced a pharmacokinetic-based function connecting PDT response to dose as a function of time postinjection. This mechanistic dose-response function was fitted to published, single time point QSAR data for the pheophorbides. As a result, the PDT target threshold dose together with the predicted QSAR as a function of time postinjection was found.

Animals↗

PubMed1983

Effects of adrenaline on a compartment of slowly-exchangeable calcium in the perfused rat heart.

The effects of adrenaline on kinetically-distinct compartments of exchangeable calcium in the spontaneously-beating perfused rat heart were investigated under steady-state conditions using a 45Ca2+ outflow technique together with a nonlinear least-squares curve fitting procedure and 51Cr-EDTA to monitor the loss of freely-diffusible Ca2+ from the extracellular space. In addition to Ca2+ distributed in the vascular (compartment 1) and interstitial (compartment 2) spaces, the minimum number of kinetically-distinct compartments of cellular exchangeable Ca2+ (which include Ca2+ bound to extracellular sites on the sarcolemma) required to fit the data (compartments 3, 4 and 5) was three. A system in which cellular compartment 3 is linked to the vascular space and compartments 4 and 5 are linked to the interstitial space was consistent with the data. For hearts perfused under control conditions, the fractional transfer rates for Ca2+ outflow from cellular compartments 3, 4 and 5 were 0.70, 0.11 and 0.017 min-1, respectively. Adrenaline increased the quantity of exchangeable Ca2+ in compartment 5 and decreased that present in the compartment 4. Evidence that compartment 5 includes mitochondrial exchangeable Ca2+ is discussed. It is concluded that one of the actions of adrenaline on the heart is to increase the quantity of exchangeable Ca2+ in the mitochondria.

Animals↗

PubMed2000

Effect of acute reamed versus unreamed intramedullary nailing on compartment pressure when treating closed tibial shaft fractures: a randomized prospective study.

OBJECTIVE: To compare anterior and deep posterior compartment pressures during reamed and unreamed intramedullary nailing of displaced, closed tibial shaft fractures. DESIGN: Randomized prospective study. SETTING: University Hospital/Level I trauma center. PATIENTS: Forty-eight adults with forty-nine fractures treated with intramedullary nailing within three days of injury. INTERVENTION: After intraoperative placement of compartment pressure monitors, the tibia fractures were treated by either unreamed intramedullary nailing or reamed intramedullary nailing. A fracture table and skeletal traction were not used in any of these procedures. MAIN OUTCOME MEASUREMENTS: Compartment pressures and deltaP ([diastolic blood pressure] - [compartment pressure]) were measured immediately preoperatively, intraoperatively, and for twenty-four hours postoperatively. RESULTS: Compartment syndrome did not occur in any patient. Peak average pressures were obtained during reaming in the reamed group (30.0 millimeters of mercury anterior compartment, 34.7 millimeters of mercury deep posterior compartment) and during nail insertion in the unreamed group (33.9 millimeters of mercury anterior compartment, 35.2 millimeters of mercury deep posterior compartment). The average pressures quickly returned to less than thirty millimeters of mercury and remained there for the duration of the study. The deep posterior compartment pressures were lower in the reamed group than in the unreamed group at ten, twelve, fourteen, sixteen, eighteen, twenty, twenty-two, and twenty-four hours postoperatively (p < 0.05 at each of these times. A statistically significant difference between anterior compartment pressures could not be shown with the numbers available. The deltaP values were greater than thirty millimeters of mercury at all times after nail insertion in both the reamed and unreamed groups. CONCLUSION: These data support acute (within three days of injury) reamed intramedullary nailing of closed, displaced tibial shaft fractures without the use of a fracture table.

Adolescent↗

PubMed1997

Bilateral acute-on-chronic exertional lateral compartment syndrome of the leg: a case report and review of the literature.

PURPOSE: We report a previously undescribed case of bilateral acute exertional compartment syndrome of the lateral compartment arising from pre-existing chronic exertional compartment syndromes. CASE SUMMARY: A 21-year-old football player had a 1-year history of bilateral chronic exertional compartment syndrome. One day after practice his usual symptoms progressed instead of abated and he presented at 3:00 AM with bilateral acute lateral compartment syndromes. His lateral compartment pressures were > 100 mm Hg. Emergency surgical releases were performed and the patient recovered well with full return to competitive football in 4 weeks. DISCUSSION: No prior case of acute-on-chronic exertional compartment syndrome of the lateral compartment has been reported. In addition, this is a case of bilateral acute exertional compartment syndrome. The literature is reviewed with discussion of differential diagnosis, distribution, pathophysiology, and treatment of exertional compartment syndrome. RELEVANCE: Failure to recognize and emergently treat progression of a chronic to an acute exertional compartment syndrome can be devastating.

Adult↗

PubMed1997

Intramuscular partial oxygen tension monitoring in compartment syndrome--an experimental study.

Measuring intracompartmental pressure is a well-accepted method in evaluating a compartment syndrome, which may occur after limb ischaemia followed by reperfusion. As a compartment syndrome is paralleled by a decreased microcirculation it should be possible also to evaluate a compartment syndrome by measuring intramuscular partial oxygen tension (PO2). In this study, anaesthetized rats (spontaneous breathing via tracheotomy) were subjected to infrarenal ligation of the aorta. A pressure catheter was placed subfascial in the crural muscle group of one hind limb, whereas the contralateral side was prepared with a PO2 catheter. Besides a sham operated group, three experimental groups were subjected to either 2, 4 or 6 h of ischaemia followed by 4 h of reperfusion. One further group was also subjected to 4 h of ischaemia and 4 h of reperfusion but received a fasciotomy at the time of reperfusion. Compartment pressure and intramuscular PO2 were recorded every 15 min. For histological examination muscle specimens were obtained after each experiment. Two hours of ischaemia followed by 4 h of reperfusion did not result in any morphological changes and also in no significant change in compartment pressure during both phases, whereas PO2 significantly dropped during ischaemia (from 19.0 mmHg to 3.0-5.0 mmHg) and returned to normal during reperfusion. In prolonged ischaemia (4 h) morphologically a severe interstitial oedema was evident, compartment pressure increased during reperfusion (from 2.0 mmHg to 8.8 mmHg) and PO2 dropped during ischaemia to 3.0 mmHg and did not return to normal during reperfusion (10.5 mmHg versus 19.0 mmHg normal). In the case of 6 h ischaemia, partial necrosis and no interstitial oedema was found morphologically. There was no significant change in compartment pressure throughout the study, and PO2 remained significantly decreased even during reperfusion (2.0-3.0 mmHg). Normal compartment pressure could mislead to false negative interpretation of microcirculatory disorders preceding or following compartment syndrome, whereas PO2 clearly identifies the microcirculatory state of the muscle. Thus, intramuscular PO2 monitoring presents a valuable method in evaluating compartment syndrome, especially where there are suspected clinical signs and risk of ischaemia but normal compartment pressure.

Animals↗

PubMed2006

Continuous compartment pressure monitoring for tibia fractures: does it influence outcome?

BACKGROUND: Compartment syndrome is common in acute fractures of the tibia. Early diagnosis is important, as delayed treatment leads to significant complications. Continuous compartment pressure monitoring has been recommended to prevent late diagnosis of compartment syndrome associated with tibia fractures. In this study, we aim to examine the effect of continuous compartment pressure monitoring on outcome in acute tibia fractures. METHODS: We randomized 200 consecutive acute extra-articular tibia fractures into monitored and nonmonitored groups. The monitored group received continuous compartment pressure for 36 hours and the nonmonitored group received usual postoperative observations. In alert patients, the diagnosis of compartment syndrome was made clinically. In unconscious patients, a difference between compartment pressure and diastolic blood pressure (DeltaP) of less than 30 mm Hg was the criteria for fasciotomy. Patients were assessed for late sequelae of compartment syndrome (sensory loss, muscle weakness, contracture, and toe clawing) at 6 months. RESULTS: Eighty-nine percent of patients were followed up for a minimum of 6 months or to fracture union. There were five cases of compartment syndrome in the nonmonitored group and none in the monitored group. At 6 months, the complication rates and late sequelae in both groups were not significantly different. In the monitored group, there were 18 patients with DeltaP less than 30 mm Hg, none of whom developed compartment syndrome or late sequelae. In both groups, patients with high energy or open fractures had significantly more late sequelae. CONCLUSIONS: Continuous compartment pressure monitoring is not indicated in alert patients who are adequately observed.

Adolescent↗

PubMed1982

Ultrasound evaluation of the anterior musculofascial compartment of the leg following exercise.

An ultrasonic method is described to measure changes in width of the anterolateral leg compartment in its lower third following exercise. In 20 normal subjects, compartment widths increased an average of 8.6% following exercise, with joggers' compartments increasing 10.1%, as compared to 7.4% in nonjoggers. Control measurements of the compartment width in a cadaver leg showed excellent correlation with the ultrasound measurement. Following exercise, vascular responses and fluid transfers caused an increase in volume of the compartment contents, which is reflected in compartment widening. Because the compartment contents are usually contained by a complete but only moderately compliant wall, intracompartmental pressure will normally rise, and symptoms of a compartment syndrome will result. Diagnosis of exertional compartment syndrome in the leg has usually been made at clinical examination. Measurement of compartment width increase is intended to complement intracompartmental pressure and aid in differentiating the diagnosis of exertional compartment syndrome from shin splints, stress fracture, and tendonitis. Additionally, muscle atrophy, hypertrophy and growth can be recorded by the ultrasound technique.

Adult↗

PubMed1981

Quantitation of skeletal-muscle necrosis in a model compartment syndrome.

UNLABELLED: Skeletal-muscle necrosis was evaluated in previously pressurized canine compartments using technetium-99m stannous pyrophosphate and classic histological criteria. Intracompartmental necrosis was quantitated in the anterolateral muscle compartment of each dog by uptake of 99mTc stannous pyrophosphate using the contralateral anterolateral compartment as an internal control. Representative specimens of muscle were sampled in experimental and control legs of each dog and were analyzed by qualitative histological techniques. Muscle necrosis was assessed in compartments forty-eight hours after pressurization to levels of ten to 120 millimeters of mercury for eight hours in thirty-seven dogs. In another dog, neither anterolateral compartment was pressurized so that both compartments acted as control muscle. The results in these experiments identify a threshold pressure level (thirty millimeters of mercury) and duration (eight hours) at which significant muscle necrosis occurs at normal blood pressure. Our findings imply that a quantitative relationship exists between incorporation of 99mTc stannous pyrophosphate and the level of intracompartmental pressure. This uptake technique, however, is not suitable for diagnosing compartment syndrome in patients with a threatened compartment syndrome. We suggest that intracompartmental pressure measurements by the wick-catheter technique, in conjunction with clinical findings, offer the best means for diagnosing compartment syndrome. CLINICAL RELEVANCE: Significant muscle necrosis associated with an impending compartment syndrome occurs at a threshold intracompartmental pressure of thirty millimeters of mercury after eight hours. Since time variables are often unknown in suspected compartment syndromes, fasciotomy is recommended when intracompartmental pressure exceeds thirty millimeters of mercury in a patient with normal blood pressure. The use of this threshold pressure level as an indication for fasciotomy requires a device for measuring intracompartmental pressure such as the wick catheter.

Animals↗

PubMed1998

[Intramuscular pO2 monitoring in compartment syndrome--an experimental study].

HYPOTHESIS: Measuring intracompartmental pressure is a well accepted method in evaluating a compartment syndrome, which may occur after limb ischemia followed by reperfusion. As a compartment syndrome is paralleled by a decreased microcirculation it should be possible to evaluate a compartment syndrome also by measuring intramuscular pO2. METHODS: Anesthetized rats (spontaneous breathing via tracheotomy) were subjected to infrarenal ligation of the aorta. A pressure catheter was placed subfascial in the crural muscle group of one hind limb, whereas the contralateral side was prepared with a pO2 catheter. Besides a sham operated group, three experimental groups were subjected to either 2 hrs, 4 hrs or 6 hrs of ischemia followed by 4 hrs of reperfusion. One further group was also subjected to 4 hrs of ischemia and 4 hrs of reperfusion but received a fasciotomy at the time of reperfusion. Compartment pressure and intramuscular pO2 were recorded every 15 min. For histological examination muscle specimen were obtained after each experiment. RESULTS: Two hours of ischemia followed by 4 hrs of reperfusion did not result in any morphological changes and also not in any significant change in compartment pressure during both phases, whereas pO2 significantly dropped during ischemia (from 19.0 mmHg to 3.0-5.0 mmHg) and returned to normal during reperfusion. In prolonged ischemia (4hrs) morphologically a severe interstitial edema was evident, compartment pressure increased during reperfusion (from 2.0 mmHg to 8.8 mmHg) and pO2 dropped during ischemia down to 3.0 mmHg and did not return to normal during reperfusion (10.5 mmHg versus 19.0 mmHg normal). In case of 6 hrs ischemia, partial necrosis and only little interstitial edema were found morphologically. There was no significant change in compartment pressure throughout the study; and pO2 remained significantly decreased even during reperfusion (2.0-3.0 mmHg). DISCUSSION: Normal compartment pressure could mislead to false negative interpretation of compartment syndrome, whereas pO2 clearly identifies the microcirculatory state of the muscle. Thus, intramuscular pO2 monitoring presents a valuable method in evaluating compartment syndrome, especially in case of suspect clinical signs but normal compartment pressure.

Animals↗

PubMed1995

Compartment-directed physical examination of the knee can predict articular cartilage abnormalities disclosed by needle arthroscopy.

OBJECTIVE: To determine whether physical examination maneuvers that focus on each knee compartment and assess crepitus at several distinct sites can specifically disclose articular cartilage abnormalities in the compartment being assessed. METHODS: Twenty patients with knee pain were examined before needle arthroscopy. Crepitus was sought from the patellofemoral compartment, medial tibiofemoral compartment, and lateral tibiofemoral compartment. Any crepitus felt in the distal tibia during a tibiofemoral stress maneuver was recorded as transmitted bony crepitus (TBC). Needle arthroscopy assessed articular cartilage (5 sites) and both menisci in each knee. RESULTS: Crepitus by conventional assessment revealed patellar cartilage disruption (69% sensitive, 50% specific) and abnormalities of tibiofemoral cartilage (67% sensitive, 40% specific) but could not indicate their location. Tibiofemoral crepitus found cartilage disruption in the compartment at a sensitivity of 22% and a specificity of 100%, and with added tibiofemoral stress, a sensitivity of 65% and a specificity of 94% (the one "false positive" had bare bone in the other compartment). TBC was detected in 7 compartments, all of which had focal bare bone on tibial and femoral surfaces; 6 other compartments had tibial bare bone without TBC. Thus, TBC was 54% sensitive and 100% specific for tibial bare bone, and 88% sensitive and 100% specific for bone-on-bone. CONCLUSION: Compartment-directed physical examination of the painful knee can locate and assess the severity of certain articular cartilage abnormalities that are not reliably found by conventional methods. Transmitted bony crepitus is a specific finding for bone-on-bone in the compartment being assessed.

Adult↗

PubMed2003

A simpler way of comparing the labelling densities of cellular compartments illustrated using data from VPARP and LAMP-1 immunogold labelling experiments.

Quantitative immunoelectron microscopy of gold label in intracellular compartments often involves calculating labelling densities (LDs). These are related to antigen concentrations and usually refer gold particle counts to the sizes of compartments on sections (for example, golds per microm(2) of organelle profile area or per microm of membrane trace length). Here, we show how LD values can be estimated more simply (without estimating areas or lengths) and also how observed and expected LD values can be used to calculate a relative labelling index (RLI) for each compartment and then test statistically for preferential (non-random) labelling. For random labelling, RLI=1. Compartment size is estimated stereologically by superimposing random test points (which hit organelle profiles in proportion to their area) or test lines (which intersect membrane traces in proportion to their length). By this means, the observed LD of a compartment (LD(obs)) can be expressed simply as golds per test point (organelles) or per intersection (membranes). Furthermore, the LD obtained by dividing total golds (on all compartments) by total points or intersections (on all compartments) is the value to be expected (LD(exp)) when compartments label randomly. For each compartment, RLI=LD(obs)/LD(exp). Statistical analysis is undertaken by comparing observed distributions of golds with predicted random distributions (calculated from point or intersection counts). A compartment is preferentially labelled if two criteria are met: (1) its RLI>1 (i.e. LD(obs) is greater than LD(exp)) and (2) its partial chi-squared value makes a substantial contribution to total chi-squared value. This approach provides a simple and efficient way of comparing LDs in different compartments. Its utility is illustrated using data from VPARP and LAMP-1 labelling experiments.

Animals↗

PubMed1996

Cholinergic innervation in the human striatum: a three-compartment model.

The mammalian striatum is divided into compartments that are anatomically and neurochemically distinct. The dorsal striatum has been described as containing two compartments, striosomes and matrix, while the ventral striatum is thought to have a more complex, multi-compartmental organization. In this study, we sought to characterize the compartmentalization of the dorsal and ventral portions of the human striatum using choline acetyltransferase as a marker. Image analysis was used to assess relative densities of immunostaining, and three distinct, choline acetyltransferase-immunostained compartments were demonstrated: intensely immunostained, moderately immunostained and weakly immunostained areas. The dorsomedial portion of the striatum was made up of moderately immunostained regions embedded within a densely immunostained background, thus manifesting the characteristic striosome/ matrix organization of the dorsal striatum. However, the ventral and lateral two-thirds of the striatum were made up of a mixture of densely immunostained, moderately immunostained and weakly immunostained areas, with the moderately immunostained region forming the bulk of the background tissue, and smaller, densely immunostained and weakly immunostained regions embedded within it. These compartments were compared to regions defined by distinct levels of acetylcholinesterase immunostaining in adjacent sections; the staining patterns produced by the two cholinergic markers were found to be identical except in some portions of the nucleus accumbens, where acetylcholinesterase immunostaining was found to be more intense than choline acetyltransferase immunostaining. The immunoreactive somata were mapped within sections stained for choline acetyltransferase taken from different rostrocaudal levels of the striatum, and the distributions and densities of immunoreactive somata within these three cholinergic compartments were determined. In general, the densities of cholinergic somata roughly correlated with immunostaining intensity of regions, e.g. the most intensely immunostained compartment also had the highest densities of cholinergic somata. However, in the rostroventral striatum, the densities of cholinergic somata in the weakly immunostained compartment roughly equalled the densities of cholinergic somata in the moderately immunostained compartment, suggesting that local axonal arborizations of cholinergic cells may differ in density or orientation between the two compartments, or, alternatively, that some of the cholinergic cells in the weakly immunostained compartment may project outside of the striatum. The large proportion of striatum displaying ventral striatal characteristics (a complex, multi-compart-mental organization) in humans relative to that observed in other mammals suggests that the role of the ventral striatum may be expanded and more highly differentiated in the human brain.

Adult↗