Non-invasive and reliable assessment of compartment elasticity by pressure related ultrasound: An in-vitro study

[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.

Chronic Exertional Compartment Syndrome in Athletes: An Overview of the Current Literature

Chronic exertional compartment syndrome is an incapacitating condition that primarily affects athletes and individuals with high activity levels. The exact etiology of the condition is unknown to date, but multiple factors play a role in its occurrence. The clinical presentation includes pain, tightness, muscle weakness, paresthesia, and cramps. Common tools utilized during the diagnostic approach include intramuscular compartment pressure measurement, advanced imaging to exclude other disorder entities, near-infrared spectrometry, and shear wave elastography, with the clinical diagnosis being the gold standard. Management includes both conservative and surgical options. Conservative treatment includes gait re-training and botulinum toxin injections. Further, the operative treatment has variable approaches and may be combined with conservative modalities. This article reviews the literature on chronic exertional compartment syndrome and elucidates future recommendations.

Non-invasive assessment of muscle compartment elasticity by pressure-related ultrasound in pediatric trauma: a prospective clinical study in 25 cases of forearm shaft fractures

BACKGROUND

Soft-tissue swelling after limb fractures in pediatric patients is well known to be a risk factor for developing acute compartment syndrome (ACS). Clinical assessment alone is uncertain in specific cases. Recently, we proposed a non-invasive ultrasound-based method to objectify muscle compartment elasticity for monitoring. We hypothesize a strong correlation between the soft-tissue swelling after stabilization of upper limb fractures and the compartment elasticity objectified with a novel ultrasound-based approach in pediatric trauma.

PATIENTS AND METHODS

In a prospective clinical study, children suffering forearm fractures but not developing an ACS were included. The muscle compartment elasticity of the m. flexor carpi ulnaris was assessed after surgical intervention by a non-invasive, ultrasound-based method resulting in a relative elasticity (RE in %) in both the control (healthy limb) and study group (fractured limb). Soft-tissue swelling was categorized in four different levels (0-3) and correlated with the resulting RE (%).

RESULTS

The RE in the study group (15.67%, SD ± 3.06) showed a significantly decreased level (p < 0.001) compared with the control (22.77%, SD ± 5.4). The categorized grade of soft-tissue swelling resulted in a moderate correlation with the RE (rs = 0.474).

CONCLUSIONS

The presented study appears to represent a novel approach to assess the posttraumatic pressure changes in a muscle compartment after fracture stabilization non-invasively. In this first clinical study in pediatric cases, our measurement method represents a low-cost, easy, and secure approach that has the potential to substitute invasive measurement of suspected ACS in muscle compartment conditions. Further investigations in lager cohorts are required to prove its daily clinical practicability and to confirm the expected reliability.

Value of Multimodality Ultrasound in Quantitative Evaluation of the Intra-compartmental Pressure and Perfusion Pressure in Acute Compartment Syndrome in a Rabbit Model

OBJECTIVE

The aim of the work described here was to investigate the feasibility of using multimodality ultrasound in quantitative evaluation of the intra-compartmental pressure (ICP) and perfusion pressure (PP) changes in acute compartment syndrome (ACS).

METHODS

Infusion technique was used to increase the ICP of the anterior compartment of 10 rabbits from baseline to 20, 30, 40, 50, 60, 70 and 80 mmHg. The anterior compartment was evaluated with conventional ultrasound, shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS). The shape of the anterior compartment, shear wave velocity (SWV) of the tibialis anterior (TA) muscle and CEUS parameters of the TA muscle were measured.

RESULTS

When the ICP exceeded 30 mmHg, the shape of the anterior compartment did not expand significantly with increasing ICP. There was a strong correlation between the SWV of TA muscle and measured ICP (ρ = 0.927). Arrival time (AT), time to peak (TTP), peak intensity (PI) and area under the curve (AUC) were significantly correlated with PP (AT, ρ = -0.763; TTP, ρ = -0.900; PI, ρ = 0.665; AUC, ρ = 0.706), whereas mean transit time (MTT) was not.

CONCLUSION

Multimodality ultrasound can be used to quantitatively evaluate ICP and PP and, thus, could provide more information for the rapid diagnosis and monitoring of ACS.

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.