Overview
Definition:
Fasciotomy for forearm compartment syndrome is a surgical procedure involving the incision and release of inelastic fascial layers that enclose the muscle compartments of the forearm
This relieves elevated intracompartmental pressure, restoring blood flow and preventing irreversible ischemic damage to muscles and nerves.
Epidemiology:
Forearm compartment syndrome is less common than in the lower leg but can occur after severe trauma (fractures, crush injuries), prolonged ischemia with reperfusion, or even with less severe injuries in susceptible individuals
Incidence is difficult to quantify due to varying definitions and reporting.
Clinical Significance:
Untreated forearm compartment syndrome can lead to permanent functional deficits, including muscle contractures (e.g., Volkmann's ischemic contracture), nerve palsy, chronic pain, and loss of sensation and motor function
Prompt diagnosis and surgical decompression are critical for limb salvage and functional recovery.
Clinical Presentation
Symptoms:
Severe, deep, and disproportionate pain out of proportion to the apparent injury
Pain that is exacerbated by passive stretch of the affected muscles
Paresthesias or numbness in the distribution of the median, ulnar, or radial nerves
Weakness in specific muscle groups depending on the affected compartment.
Signs:
Tense, swollen, and firm forearm
Pain with passive finger or wrist extension
Pallor or cyanosis of the digits (late sign)
Absent or diminished pulses (late sign)
Decreased sensation to light touch
Motor deficits in intrinsic hand muscles or extrinsic finger flexors/extensors.
Diagnostic Criteria:
Clinical diagnosis is paramount and based on the classic signs and symptoms
While objective pressure measurements can support the diagnosis, they are not always available or practical in emergent settings
A high index of suspicion is key
The classic five Ps (Pain, Pallor, Pulselessness, Paresthesia, Paralysis) are often present in advanced stages.
Diagnostic Approach
History Taking:
Detailed history of injury mechanism (blunt trauma, crush injury, fracture, burn, prolonged immobility, reperfusion injury)
Time elapsed since injury
Any previous orthopedic interventions or vascular access
Presence of other comorbidities that may affect perfusion.
Physical Examination:
Palpation of the forearm for tenseness and swelling
Assess all compartments
Test passive stretch of finger and wrist joints for pain provocation
Perform sensory and motor testing for all nerve distributions and muscle groups
Assess capillary refill and skin color of digits.
Investigations:
Compartmental pressure monitoring: Normal forearm intracompartmental pressure is <10 mmHg
A delta pressure (diastolic blood pressure - intracompartmental pressure) of <20-30 mmHg is highly suggestive of compartment syndrome
Imaging (X-ray, CT, MRI) may reveal associated fractures or soft tissue injuries but typically do not diagnose compartment syndrome itself
Ultrasound can sometimes identify fascial bulging.
Differential Diagnosis:
Fractures with associated soft tissue swelling
Deep vein thrombosis
Cellulitis
Peripheral nerve injury
Arterial injury
Tendon rupture
Burn eschar.
Management
Initial Management:
Remove any constricting dressings, casts, or splints
Elevate the limb to the level of the heart (avoid excessive elevation which can worsen ischemia)
Avoid local pressure
Administer analgesia
Consult orthopedic surgery immediately.
Medical Management:
Strict monitoring of vital signs and neurological status
Pain control with intravenous analgesics
Avoidance of drugs that can compromise perfusion
Tetanus prophylaxis if indicated.
Surgical Management:
Fasciotomy is indicated when intracompartmental pressure is elevated (typically >30 mmHg, or a delta pressure <20-30 mmHg)
The goal is to divide the fascia of all involved compartments
The standard approach involves multiple longitudinal incisions over the most tense compartments
The dorsal compartment (extensor muscles) and volar compartments (flexor muscles) are typically addressed
In severe cases, decompressive fasciotomy may also involve the intrinsic hand muscles.
Supportive Care:
Aggressive wound care post-fasciotomy
Frequent neurological and vascular checks
Pain management
Antibiotics if infection is suspected
Mobilization as tolerated once stable
Physiotherapy and occupational therapy are crucial for functional recovery.
Complications
Early Complications:
Hemorrhage from the fasciotomy incisions
Nerve injury during the procedure
Infection at the incision sites
Incomplete decompression leading to persistent ischemia
Compartment syndrome in an unaddressed compartment.
Late Complications:
Volkmann's ischemic contracture
Chronic pain
Significant functional deficits (loss of grip strength, fine motor skills)
Scarring and adhesions
Sensory loss
Nerve entrapment in scar tissue
Malunion or nonunion of associated fractures.
Prevention Strategies:
Prompt recognition and treatment of compartment syndrome
Careful application of casts and dressings
Avoiding circumferential dressings that can constrict
Vigilant monitoring post-injury or surgery
Early decompressive fasciotomy when indicated.
Prognosis
Factors Affecting Prognosis:
Timeliness of diagnosis and intervention is the most critical factor
The severity of the initial injury
The extent of ischemic damage
The patient's age and overall health status
The adequacy of the surgical decompression
Adherence to postoperative rehabilitation.
Outcomes:
With timely and adequate fasciotomy, functional recovery can be good, though often with some residual deficits
Delayed or missed diagnosis significantly worsens the prognosis, often leading to permanent disability
Long-term rehabilitation is essential for maximizing functional outcome.
Follow Up:
Regular follow-up with orthopedic surgery is required
This includes monitoring for wound healing, assessing for signs of infection, evaluating nerve function, and assessing muscle strength and joint range of motion
Extensive physiotherapy and occupational therapy are typically needed for several months to years post-operatively.
Key Points
Exam Focus:
High suspicion is key for diagnosis
Pain with passive stretch is a hallmark sign
The delta pressure of <20-30 mmHg is a critical indicator for fasciotomy
All compartments (dorsal, volar) should be considered for decompression
Volkmann's contracture is a dreaded sequela of untreated compartment syndrome.
Clinical Pearls:
Never underestimate forearm pain following trauma
If compartment syndrome is suspected, do not wait for pulselessness
it is a late and ominous sign
Liberalize fasciotomy in equivocal cases
the consequences of delayed decompression are far worse than those of an unnecessary fasciotomy
Aggressive rehabilitation is paramount for functional recovery.
Common Mistakes:
Delaying fasciotomy due to indecision or lack of pressure monitoring
Incomplete decompression by not addressing all involved compartments
Inadequate postoperative care and rehabilitation
Overreliance on objective measurements when clinical suspicion is high.