Mangled Extremity Severity Score (MESS)
About the Mangled Extremity Severity Score
The Mangled Extremity Severity Score (MESS) is a scoring system used to assess the severity of extremity trauma and predict the need for amputation. It was developed by Johansen et al. in 1990 and has been widely used in trauma centers to guide decision-making in cases of severe limb injuries.
The MESS takes into account four critical factors: skeletal/soft tissue injury, limb ischemia, shock, and patient age. Each factor is assigned a score, and the total score helps predict the likelihood of limb salvage versus amputation.
Clinical Use
The MESS is used in the initial assessment of patients with severe extremity trauma to help guide treatment decisions. A score of 7 or greater has been associated with a high likelihood that amputation will be necessary.
It's important to note that the MESS is just one tool in the decision-making process. The final decision regarding limb salvage versus amputation should be made by an experienced trauma team considering all clinical factors, including the patient's overall condition, associated injuries, and available resources.
Score Components
Skeletal/Soft Tissue Injury
- Low energy (simple fracture, civilian gunshot wound, small knife wound): 1 point
- Medium energy (open or multiple fractures, dislocation): 2 points
- High energy (close-range shotgun or high-velocity gunshot wound, crush injury): 3 points
- Very high energy (above + gross contamination, soft tissue avulsion): 4 points
Limb Ischemia
- Normal perfusion: 0 points
- Reduced pulse but normal perfusion: 1 point
- Pulseless, paresthesias, diminished capillary refill: 2 points
- Cool, paralyzed, insensate, numb: 3 points (doubled if ischemia > 6 hours)
Shock
- Systolic BP > 90 mmHg consistently: 0 points
- Hypotension transiently: 1 point
- Persistent hypotension: 2 points
Age
- < 30 years: 0 points
- 30-50 years: 1 point
- > 50 years: 2 points
Score Interpretation
| MESS Score | Interpretation |
|---|---|
| < 7 | Limb salvage likely to be successful |
| ≥ 7 | Amputation likely to be necessary |
Limitations
- The MESS was developed before many modern advances in microsurgery, vascular surgery, and critical care.
- Some studies have questioned its predictive value in certain populations or injury patterns.
- The score does not account for associated nerve injuries, which can significantly impact functional outcomes.
- It does not consider patient comorbidities or functional requirements.
- The decision to amputate should never be based solely on a scoring system.
References
- Johansen K, Daines M, Howey T, Helfet D, Hansen ST Jr. Objective criteria accurately predict amputation following lower extremity trauma. J Trauma. 1990;30(5):568-572.
- Bosse MJ, MacKenzie EJ, Kellam JF, et al. A prospective evaluation of the clinical utility of the lower-extremity injury-severity scores. J Bone Joint Surg Am. 2001;83(1):3-14.
- Sheean AJ, Krueger CA, Napierala MA, Stinner DJ, Hsu JR; Skeletal Trauma Research Consortium (STReC). Evaluation of the mangled extremity severity score in combat-related type III open tibia fracture. J Orthop Trauma. 2014;28(9):523-526.