Continuous Near-Infrared Spectroscopy Demonstrates Limitations in Monitoring the Development of Acute Compartment Syndrome in Patients with Leg Injuries

Trimodal wireless intramuscular device detects muscle pressure, flow, and oxygenation changes in porcine model of lower extremity compartment syndrome

PURPOSE

Compartment syndrome remains difficult to diagnose early in its clinical course. Pressure transducer catheters have been used to directly measure intracompartmental pressure (ICP), but this method is unreliable, with a false positive rate of 35%. We have previously used intramuscular near infrared spectroscopy to detect changes in tissue oxygen saturation (StO2) in response to increasing ICP using a novel implantable probe. However, measuring StO2 may not be sufficient to identify CS in the clinical setting. The pathophysiology of CS consists of increased ICP, leading to decreased tissue perfusion, and resulting in reduced tissue oxygenation. More clinically useful information may come from the integration of multiple data streams to aid in the diagnosis of CS. In this study, we present a novel, intramuscular probe capable of simultaneous measurement of ICP, StO2, and microvascular blood flow in a porcine model of ACS.

METHODS

Proof of concept for this device is demonstrated in a porcine lower extremity balloon compression model of ACS. Pressure was maintained for 20 min (short-term) or 3 h (long-term) before the balloon volume was removed.

RESULTS

In both short- and long-term experiments, as ICP increased with increasing balloon volume, the novel multimodal sensor simultaneously and reliably detected pressure elevation and corresponding reversible reductions in microvascular flow rate and tissue oxygenation.

CONCLUSION

This novel trimodal device simultaneously measured the elevated ICP, decreased perfusion, and tissue ischemia of evolving ACS, substantiating our basic understanding of CS pathophysiology.

[Diagnostics of acute compartment syndrome : Current gold standard and the state of science of noninvasive assessment methods]

Acute compartment syndrome (ACS) is defined by a disorder of the microcirculation due to a persistent pathological pressure increase within a muscle compartment. The ischemia of the tissue leads to an initially reversible functional impairment and finally irreversible damage of the musculature, nerves and other structures. Based on the understanding of the pathophysiology, the current diagnostic concepts and treatment using the so-called dermatofasciotomy of the affected muscle compartments can be derived. In addition to the suspicion of a possible ACS based on the medical history of the patient, the findings of the clinical examination are decisive. This review article gives a summary of all the essential aspects of the diagnostics. In clinically uncertain cases and for monitoring, an objectification of the findings using instrument-based techniques is increasingly required. Nowadays, invasive needle pressure measurement is available; however, due to limited reliability, specificity and sensitivity, these measurements only represent an aid to decision guidance supporting or advising against the indications for dermatofasciotomy. The increasing demands on making a certain diagnosis and justification of a surgical intervention from a legal point of view, substantiate the numerous scientific efforts to develop noninvasive instrument-based diagnostics. These methods are based either on detection of increasing intracompartmental pressure or decreasing perfusion pressure and microcirculation. The various measurement principles are summarized in a lucid form.

The Major Extremity Trauma Research Consortium: Development and Impact of an Orthopaedic Trauma Research Program

The Major Extremity Trauma Research Consortium (METRC) is a unique and ongoing military-civilian collaboration that resulted in the largest orthopaedic trauma research enterprise to date. The Consortium was established in September 2009 with funding from the Department of Defense. It employs a centralized data coordinating center and has grown into a network of nearly 400 investigators at 70 clinical centers. METRC conducts large multicenter clinical research studies selected and designed to improve outcomes among severely injured military and civilian patients with extremity trauma. Over the past decade, the consortium has implemented 35 such studies distributed among 19 principal investigators, enrolled more than 23,000 patients, published 61 articles, and received more than $150 million in funding from the Department of Defense, Patient Centered Outcomes Research Institute, and National Institutes of Health. This unique multidisciplinary research platform is a powerful community capable of addressing the challenging issues related to the evaluation, treatment, and recovery after severe extremity trauma. This body of work received the 2023 Elizabeth Winston Lanier Kappa Delta Award. An overview of the METRC development, organization, and research focus areas is presented.

Comparison and convergence of compartment syndrome techniques: a narrative review

INTRODUCTION

Compartment syndrome (CS) continues to be a legitimate orthopedic emergency as it leads to thousands of amputations and permanent nerve and tissue damage to undiagnosed patients for more than eight hours. In CS, intracompartmental pressure is elevated, causing reduced blood flow inside the limb compartments. An erroneous diagnosis may result in unnecessary fasciotomies, the only treatment for this condition.

AREAS COVERED

This review examines the previous and current diagnostic and therapeutic practices for compartment syndrome. It also performs a comparative analysis of each diagnostic technique and its foresights.

EXPERT OPINION

Currently, most clinicians rely on a physical examination of the patient to diagnose CS. The primary reason for the physical examination is the lack of a gold-standard device. The invasive intracompartmental pressure (ICP) measurement technique is still the most commonly used. On the other hand, many non-invasive approaches have the potential to be used as diagnostic tools; however, more research is needed before they can be accepted as standard clinical approaches.

Percutaneously introduced wireless intramuscular near-infrared spectroscopy device detects muscle oxygenation changes in porcine model of lower extremity compartment syndrome

Serial examination and direct measurement of intracompartmental pressure (ICP) are suboptimal strategies for the detection of acute compartment syndrome (CS) because they are operator-dependent and yield information that only indirectly reflects intracompartmental muscle perfusion. As a result, instances of unnecessary fasciotomy and unrecognized CS are relatively common. Recently, near-infrared spectroscopy (NIRS)-based systems for compartment monitoring have generated interest as an adjunct tool. Under ideal conditions, NIRS directly measures the oxygenation of intracompartmental muscle (StO₂ ), thereby obviating the challenges of interpreting equivocal clinical examination or ICP data. Despite these potential advantages, existing NIRS sensors are plagued by technical difficulties that limit clinical utility. Most of these limitations relate to their transcutaneous design that makes them susceptible to both interference from intervening skin/subcutaneous tissue, underlying hematoma, and instability of the skin-sensor interface. Here, we present a flexible, wireless, Bluetooth-enabled, percutaneously introducible intramuscular NIRS device that directly and continuously measures the StO₂ of intracompartmental muscle. Proof of concept for this device is demonstrated in a swine lower extremity balloon compression model of acute CS, wherein we simultaneously track muscle oxygenation, ICP, and compartment perfusion pressure (PP). The observed StO₂ decreased with increasing ICP and decreasing PP and then recovered following pressure reduction. The mean change in StO₂ as the PP was decreased from baseline to 30 mmHg was -7.6%. The mean difference between baseline and nadir StO₂ was -17.4%. Cross-correlations (absolute value) describing the correspondence between StO₂ and ICP were >0.73. This novel intramuscular NIRS device identifies decreased muscle perfusion in the setting of evolving CS.

Well Leg Compartment Syndrome: Pathophysiology, Prevention, and Treatment

The development of compartment syndrome involving the lower limb is a potentially devastating complication of prolonged surgery in patients held in the lithotomy position. Well leg compartment syndrome (WLCS) was recognized in 1953. The incidence of this condition has been reported to range from 0.20% to 0.03%. The mechanism of WLCS development in the absence of trauma appears to be related to prolonged hypoperfusion of the limb, pressure on the muscle compartments, and in some cases, reperfusion of the ischemic limb. This grave complication develops either during or immediately after prolonged surgery in which the patient was held in the Lloyd-Davies lithotomy or hemi-lithotomy position. Surgeons must be aware of the potential for WLCS development during prolonged surgery. Signs of developing WLCS include swelling, increased firmness of the muscle compartments, discoloration, and cooling of the limb. Preventive measures can be taken without contaminating the surgical field by returning the limb to the right atrium level. Once the diagnosis has been made, failure to prevent the development of WLCS requires extensile fasciotomy of each leg compartment to restore perfusion and relieve elevated intra-compartment pressures. This article reviews the pathophysiology, prevention, and treatment of WLCS.

Extremity compartment syndrome: A review with a focus on non-invasive methods of diagnosis

The article deals with an overview of acute extremity compartment syndrome with a focus on the option of non-invasive detection of the syndrome. Acute extremity compartment syndrome (ECS) is an urgent complication that occurs most often in fractures or high-energy injuries. There is still no reliable method for detecting ECS. The only objective measurement method used in clinical practice is an invasive measurement of intramuscular pressure (IMP). The purpose of this paper is to summarize the current state of research into non-invasive measurement methods that could allow simple and reliable continuous monitoring of patients at risk of developing ECS. Clinical trials are currently underway to verify the suitability of the most studied method, near-infrared spectroscopy (NIRS), which is a method for measuring the local oxygenation of muscle compartments. Less explored methods include the use of ultrasound, ultrasound elastography, bioimpedance measurements, and quantitative tissue hardness measurements. Finding a suitable method for continuous non-invasive monitoring of the syndrome would greatly improve the quality of care for patients at risk. ECS must be diagnosed quickly and accurately to prevent irreversible tissue damage that can occur within hours of syndrome onset and may even warrant amputation if neglected.

BioFACTS: biomarkers of rhabdomyolysis in the diagnosis of acute compartment syndrome - protocol for a prospective multinational, multicentre study involving patients with tibial fractures

INTRODUCTION

The ischaemic pain of acute compartment syndrome (ACS) can be difficult to discriminate from the pain linked to an associated fracture. Lacking objective measures, the decision to perform fasciotomy is based on clinical findings and performed at a low level of suspicion. Biomarkers of muscle cell damage may help to identify and monitor patients at risk, similar to current routines for patients with acute myocardial infarction. This study will test the hypothesis that biomarkers of muscle cell damage can predict ACS in patients with tibial fractures.

METHODS AND ANALYSIS

Patients aged 15-65 years who have suffered a tibial fracture will be included. Plasma (P)-myoglobin and P-creatine phosphokinase will be analysed at 6-hourly intervals after admission to the hospital (for 48 hours) and-if applicable-after surgical fixation or fasciotomy (for 24 hours). In addition, if ACS is suspected at any other point in time, blood samples will be collected at 6-hourly intervals. An independent expert panel will assess the study data and will classify those patients who had undergone fasciotomy into those with ACS and those without ACS. All primary comparisons will be performed between fracture patients with and without ACS. The area under the receiver operator characteristics curves will be used to identify the success of the biomarkers in discriminating between fracture patients who develop ACS and those who do not. Logistic regression analyses will be used to assess the discriminative abilities of the biomarkers to predict ACS corrected for prespecified covariates.

ETHICS AND DISSEMINATION

The study has been approved by the Regional Ethical Review Boards in Linköping (2017/514-31) and Helsinki/Uusimaa (HUS/2500/2000). The BioFACTS study will be reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology recommendations.

TRIAL REGISTRATION NUMBER

NCT04674592.

Defining Incidence of Acute Compartment Syndrome in the Research Setting: A Proposed Method From the PACS Study

OBJECTIVE

To compare the retrospective decision of an expert panel who assessed likelihood of acute compartment syndrome (ACS) in a patient with a high-risk tibia fracture with decision to perform fasciotomy.

DESIGN

Prospective observational study.

SETTING

Seven Level 1 trauma centers.

PATIENTS/PARTICIPANTS

One hundred eighty-two adults with severe tibia fractures.

MAIN OUTCOME MEASUREMENTS

Diagnostic performance (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver-operator curve) of an expert panel's assessment of likelihood ACS compared with fasciotomy as the reference diagnostic standard.

SECONDARY OUTCOMES

The interrater reliability of the expert panel as measured by the Krippendorff alpha. Expert panel consensus was determined using the percent of panelists in the majority group of low (expert panel likelihood of ≤0.3), uncertain (0.3-0.7), or high (>0.7) likelihood of ACS.

RESULTS

Comparing fasciotomy (the diagnostic standard) and the expert panel's assessment as the diagnostic classification (test), the expert panel's determination of uncertain or high likelihood of ACS (threshold >0.3) had a sensitivity of 0.90 (0.70, 0.99), specificity of 0.95 (0.90, 0.98), PPV of 0.70 (0.50, 0.86), and NPV of 0.99 (0.95, 1.00). When a threshold of >0.7 was set as a positive diagnosis, the expert panel assessment had a sensitivity of 0.67 (0.43, 0.85), specificity of 0.98 (0.95, 1.00), PPV of 0.82 (0.57, 0.96), and NPV of 0.96 (0.91, 0.98).

CONCLUSION

In our study, the retrospective assessment of an expert panel of the likelihood of ACS has good specificity and excellent NPV for fasciotomy, but only low-to-moderate sensitivity and PPV. The discordance between the expert panel-assessed likelihood of ACS and the decision to perform fasciotomy suggests that concern regarding potential diagnostic bias in studies of ACS is warranted.

LEVEL OF EVIDENCE

Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

A dual-sensor ultrasound based method for detecting elevated muscle compartment pressures: A prospective clinical pilot study

BACKGROUND

Acute compartment syndrome (ACS) is a limb-threatening condition associated with elevated muscle compartment pressures (MCPs). The only existing treatment of ACS is to reduce MCP by fasciotomy; however, a reliable clinical method for detecting elevated MCPs is lacking. A dual-sensor (ultrasound and pressure) technology to detect elevated MCPs was previously tested on cadavers. Our goal was to examine the use of this technology in the clinical setting.

METHODS

Patients with tibia fractures were prospectively enrolled. Observers used a dual-sensor probe to measure the amount of pressure required to flatten the anterior compartment fascia (CFFP). Direct-MCP measurements and 4-compartment fasciotomy were done for suspected ACS.

RESULTS

Fifty-two patients were enrolled into the study. Nine patients underwent fasciotomy for a clinical diagnosis of ACS. Both CFFP (p-value = 8.395e-08) and delta-CFFP (p-value = 4.114e-05) were significantly larger in the fasciotomy group compared to the non-fasciotomy group. CFFP measurements showed very strong correlations to the direct MCP measurements (p-value = 0.006746, rho = 0.9285714), and delta-CFFP showed strong correlation (p-value = 0.06627, rho = 0.75). CFFP measurements had good inter-observer variability, with an interclass correlation (ICC) of 0.814 (95%-Confidence Interval: 0.631-0.907) and excellent intra-observer variability with an ICC of 0.942 (95%-Confidence Interval: 0.921-0.958).

CONCLUSION

The results of this pilot study suggest that the proposed ultrasound-based method is useful in detecting elevated MCPs and may be helpful in the diagnosing ACS or ruling out the need for urgent fasciotomy. Large-scale clinical trials are needed to validate these claims.

Perfusion Pressure Lacks Diagnostic Specificity for the Diagnosis of Acute Compartment Syndrome

OBJECTIVE

To evaluate the diagnostic performance of perfusion pressure (PP) thresholds for fasciotomy.

DESIGN

Prospective observational study.

SETTING

Seven Level-1 trauma centers.

PATIENTS/PARTICIPANTS

One hundred fifty adults with severe leg injuries and ≥2 hours of continuous PP data who had been enrolled in a multicenter observational trial designed to develop a clinical prediction rule for acute compartment syndrome (ACS).

MAIN OUTCOME MEASUREMENTS

For each patient, a given PP criterion was positive if it was below the specified threshold for at least 2 consecutive hours. The diagnostic performance of PP thresholds between 10 and 30 mm Hg was determined using 2 reference standards for comparison: (1) the likelihood of ACS as determined by an expert panel who reviewed each patient's data portfolio or (2) whether the patient underwent fasciotomy.

RESULTS

Using the likelihood of ACS as the diagnostic standard (ACS considered present if median likelihood ≥70%, absent if <30%), a PP threshold of 30 mm Hg had diagnostic sensitivity 0.83, specificity 0.53, positive predictive value 0.07, and negative predictive value 0.99. Results were insensitive to more strict likelihood categorizations and were similar for other PP thresholds between 10- and 25-mm Hg. Using fasciotomy as the reference standard, the same PP threshold had diagnostic sensitivity 0.50, specificity 0.50, positive predictive value 0.04, negative predictive value 0.96.

CONCLUSION

No value of PP from 10 to 30 mm Hg had acceptable diagnostic performance, regardless of which reference diagnostic standard was used. These data question current practice of diagnosing ACS based on PP and suggest the need for further research.

LEVEL OF EVIDENCE

Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

The Incidence and Risk Factors Associated With the Need for Fasciotomy in Tibia and Forearm Fractures: An Analysis of the National Trauma Data Bank

OBJECTIVE

The aims of this study were to analyze a large national trauma database to determine the incidence of, risk factors for, and outcomes after a fasciotomy of the lower leg or forearm after fracture.

METHODS

Data from the National Trauma Data Bank for the years 2004-2016 were analyzed, and we identified 301,351 patients with forearm fractures and 369,237 patients with tibial fractures. Risk factors, length of stay (LOS), and mortality were assessed to determine associations with an injury that required a fasciotomy.

RESULTS

A total of 1.22% of the forearm fractures and 3.79% of the tibial fractures had a fasciotomy. Patients with a fasciotomy were more likely to have invasive procedures (P < 0.0001); have injuries resulting from machinery, motor vehicle collisions, and firearms (P < 0.0001); and smoke, use drugs, and/or alcohol (P < 0.05) compared with patients who did not undergo fasciotomies. Fasciotomy procedures were associated with longer LOS and higher mortality rate (P < 0.05).

CONCLUSIONS

The incidence of a fasciotomy is less than 5% in tibia or forearm fractures. Patients who underwent fasciotomy have higher energy injuries, increased alcohol or drug use, higher rates of surgical interventions, and increased LOS. Furthermore, having a fasciotomy is associated with increased mortality rate. When counseling patients and evaluating surgeon/hospital performance, fasciotomies can serve as an indicator and modifier for a more complex trauma pathology.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Noninvasive diagnostics for extremity compartment syndrome following traumatic injury: A state-of-the-art review

Acute compartment syndrome (ACS) is a serious medical condition that can occur following traumatic injury to an extremity. If left undiagnosed, ACS can eventuate in amputation of the limb or even death. Because of this, fasciotomy to release the pressure within the muscle and restore tissue perfusion is often performed upon suspicion of ACS, as the sequelae to fasciotomy are less severe than those associated with not performing the fasciotomy. Currently, the "gold standard" of diagnosis is based on clinical assessment of such symptoms as pain out of proportion to the injury, obvious high pressure and swelling, pain on passive stretch of the muscles in the affected compartment, and deficits in sensory and/ormotor functions. Diagnosis is often confirmed using invasive measurements of intramuscular pressure (IMP); however, controversy exists as to how direct IMP measurement should be accomplished and threshold pressures for accurate diagnosis. Because of this and the attendant issues with invasive measurements, investigators have been searching over the last 25 years for a noninvasive means to quantitatively measure IMP or perfusion to the limb. The purpose of this review is to summarize the current state of the art of noninvasive devices that could potentially be used to diagnose ACS accurately and objectively. To do this, we divide the discussion into those medical devices that primarily measure mechanical surrogates of IMP (e.g., tissue hardness or myofascial displacement) and those that primarily measure indices of tissue perfusion (e.g., tissue oxygen saturation via near-infraredspectroscopy). While near-infrared spectroscopy-basedtechnologies have shown the most promise, whether such technologies will be of diagnostic benefit await the completion of ongoing clinical trials. LEVEL OF EVIDENCE: Systematic Review, level II.