Compartment syndrome of the hand following CT contrast extravasation

An 80-year-old woman was admitted to the hospital for investigation of syncopal episodes. A CT scan of the brain with contrast was ordered by the medical team for further analysis. Whilst undergoing the scan, there was extravasation of contrast through the cannula in the dorsum of the right hand. She had a past medical history of atrial fibrillation (AF), for which she was anticoagulated with Apixaban. Secondarily to the extravasation, a haematoma, likely associated with the anti-coagulant effect of Apixaban, also formed at the site of cannulation. In combination, these factors lead to the development of acute compartment syndrome (ACS) of the hand (See Fig. 1). The patient was examined by the plastic surgery registrar oncall who noted the patient was in significant discomfort, the hand and fingers were pale and grossly swollen, and the skin on the dorsum of the hand was threatened. The patient was expedited to theatre where evacuation of the contrast and haematoma was carried out under general anaesthetic. Fasciotomies of the hand compartments and carpal tunnel decompression were performed (See Fig. 2). Despite this intervention, the patient experienced extensive necrosis of the dorsal skin of her hand which subsequently required debridement and split skin grafting. (See Fig. 3). At follow up in clinic the skin grafts had healed and the patients function improved slowly with hand therapy. ACS is condition that results from an increase in pressure in one of the body’s closed fascial compartments. This can lead to irreversible muscle and nerve damage due to a decrease in perfusion pressure and resultant ischaemia. ACS presents as paraesthesia that may progress to anaesthesia and paralysis as nerve ischaemia worsens, severe pain disproportionate to the causative procedure or trauma and pallor is present. ACS can be caused by acute fractures, as well crush injuries, burns, infections and penetrating traumas but ultimately can be caused by anything that raises the pressure of a closed compartment. The hand is composed of 11 compartments separated by rigid fascia continuous with the fascia of the forearm: four dorsal and three volar interossei compartments as well as the thenar, hypothenar, adductor and mid-palm compartments. Muscles of the thenar compartment include abductor pollicis brevis, flexor pollicis brevis and opponens pollicis. Lying deep to these, the adductor compartment contains adductor pollicis. The dorsal and palmar interossei spaces lie adjacent to each other between the metacarpal bones and can be accessed through common incisions through the dorsum of the

An 80-year-old woman was admitted to the hospital for investigation of syncopal episodes. A CT scan of the brain with contrast was ordered by the medical team for further analysis. Whilst undergoing the scan, there was extravasation of contrast through the cannula in the dorsum of the right hand. She had a past medical history of atrial fibrillation (AF), for which she was anticoagulated with Apixaban. Secondarily to the extravasation, a haematoma, likely associated with the anti-coagulant effect of Apixaban, also formed at the site of cannulation. In combination, these factors lead to the development of acute compartment syndrome (ACS) of the hand (See Fig. 1). The patient was examined by the plastic surgery registrar oncall who noted the patient was in significant discomfort, the hand and fingers were pale and grossly swollen, and the skin on the dorsum of the hand was threatened.
The patient was expedited to theatre where evacuation of the contrast and haematoma was carried out under general anaesthetic. Fasciotomies of the hand compartments and carpal tunnel decompression were performed (See Fig. 2). Despite this intervention, the patient experienced extensive necrosis of the dorsal skin of her hand which subsequently required debridement and split skin grafting. (See Fig. 3). At follow up in clinic the skin grafts had healed and the patients function improved slowly with hand therapy.
ACS is condition that results from an increase in pressure in one of the body's closed fascial compartments. This can lead to irreversible muscle and nerve damage due to a decrease in perfusion pressure and resultant ischaemia. ACS presents as paraesthesia that may progress to anaesthesia and paralysis as nerve ischaemia worsens, severe pain disproportionate to the causative procedure or trauma and pallor is present.
ACS can be caused by acute fractures, as well crush injuries, burns, infections and penetrating traumas but ultimately can be caused by anything that raises the pressure of a closed compartment. The hand is composed of 11 compartments separated by rigid fascia continuous with the fascia of the forearm: four dorsal and three volar interossei compartments as well as the thenar, hypothenar, adductor and mid-palm compartments. Muscles of the thenar compartment include abductor pollicis brevis, flexor pollicis brevis and opponens pollicis. Lying deep to these, the adductor compartment contains adductor pollicis. The dorsal and palmar interossei spaces lie adjacent to each other between the metacarpal bones and can be accessed through common incisions through the dorsum of the hand. The mid-palm compartment is continuous with the carpal tunnel of the wrist. It contains flexor tendons, lumbricals, the superficial palmar arch and the digital nerves and vessels of the medial three-and-a-half fingers. The hypothenar compartment contains four muscles: abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi muscle, and palmaris brevis.
Extravasation of contrast is a rare complication of contrastenhanced CT scans, occurring in around 0.9% of patients and causing local reactions in approximately a quarter of these cases. 1,2 Several studies have identified contrast extravasation as a cause of ACS due to its direct mechanical compression of the region it enters. 3 While most extravasations cause mild discomfort, redness and swelling, the risk of more extensive tissue injury, ulceration and ACS is associated with a greater volume of extravasated fluid, with the use of hyperosmotic contrast and with the speed and route of injection. 3 Several methods have been suggested to decrease the frequency and harm of extravasation including the use of non-ionic, low osmolarity contrast, the supervision of contrast injecting pumps, the implementation of technologies that detect and notify of extravasation and direction of the patient to report discomfort at the site of cannulation. 4 Haematomas are also an established precipitating factor in the development of compartment syndrome. The risk of major bleeding in those taking Apixaban was found to be 3.3% per year compared to 0.15%-0.64% for those not receiving antiplatelet or anticoagulant therapy. 5,6 This was significantly lower than the risk when taking other anticoagulants such as Warfarin and Rivaroxaban but is important to consider when undergoing interventions that risk haematoma and haemorrhage formation such as intravenous cannulation. Despite this, it is currently considered safe to continue anticoagulant therapy before undergoing venous cannulation for interventional procedures. 7 Urgent surgical decompression of all affected compartments through fasciotomy is currently the gold standard of treatment for ACS. Initially, the patient should be closely monitored, any external compression such as a cast should be removed and the affected limb should be elevated above the level of the heart to balance the effort to maintain perfusion with the need to limit excessive swelling. Mubarek et al. suggest patients undergo fasciotomy if their intracompartmental pressure (ICP) exceeds 30 mmHg or if they are systemically hypotensive and their ICP exceeds 20 mmHg. 8 Rorabeck et al. found that fasciotomies performed within 6 h almost always resulted in complete return of limb function. 9 However, the likelihood of complete return of function is rapidly reduced the longer the delay before surgery. Approximately a third of patients undergoing fasciotomies experience complications postoperatively including necrosis of affected tissue, wound dehiscence, graft infection, neurological deficits and chronic regional pain. 10 Other complications of ACS include rhabdomyolysis, resulting in renal failure. Specifically in the upper limb a delayed presentation of ACS may result in a Volkmann's contracture: a claw-like deformity caused by permanent flexion at the wrist, hand and fingers.
Acute compartment syndrome resulting from extravasation of contrast fluid is a rare but potential consequence of contrastenhancing CT scans. Decompressive fasciotomy is an effective treatment for such cases but efforts should be made to reduce the risk of extravasation where possible. Further research into the specific factors that increase the risk of harm from contrast infusion will provide better direction for future clinical practise.