Mangled Extremity Severity Score (MESS)

MESS explained

The mangled extremity severity score evaluates how severe limb trauma is (particularly lower extremity trauma) and helps discriminate between salvageable limbs and cases where amputation is likely.

This early prognosis score can be used in the emergency department and accounts for the following limb trauma characteristics:

*Trauma patients undergo a thorough trauma assessment and resuscitation and after initial stabilization in the ER, an orthopaedics consultation should be done as a matter of urgency to reduce type of ischemia.

**Simple fractures, stabbings or gunshots are considered low energy, dislocations or multiple fractures have medium energy while high spend MVA, rifle shots and in general most high speed trauma are at the high end. Injuries that have a high energy mechanism also result in gross contamination from the exposure to the environment.

Result interpretation

The result provided by the MESS can discriminate between a salvageable limb and one that requires empiric amputation.

Each of the five items in the score is awarded a number of points and the final score results from summing them. A cut-off at 7 points was established in the original study. This indicates that all patients scoring above 7 are at increased risk of amputation.

However, this cut-off is consistent with findings from the 1990s. Current surgical techniques may suggest that limb trauma previously considered unsalvageable has more chances, thus a cut off of 8 or 9 would be more relevant.

The MESS is used in the trauma assessment centre during the initial evaluation of the patient with lower or upper extremity trauma, along other tools, such as the Gustilo Classification of injury. The GCI states whether the wound is grade I, II or III while observing the bone puncture and tissue and vascularisation damage.

Whilst a perfectly accurate prediction of amputation risk is not entirely possible, the MESS offers important information about the characteristics of trauma, even in cases where skeletal or soft tissue repairing and reconstruction are necessary.

About the study

The MESS was created in 1990 by Johansen et al., following a retrospective analysis of severe lower extremity injuries in 25 trauma victims. The initial results indicated a cut of level at the score of 6. A derived larger center study then settled the score of 7 as the 100% cut off for amputation procedures.

A subsequent prospective trial of MESS in lower extremity injuries showed prediction accuracy.

The model was found to have a poor specificity but high sensitivity in scoring trauma patients with injuries of the extremities thus allowing triage, classification and outcome prediction.

Other trauma assessments

There are several anatomic trauma assessments that are used in emergency rooms to evaluate the severity of injuries and stratify patients in regard to adverse outcome risk. These are some examples:

■ Abbreviated Injury Score (AIS);

■ Injury Severity Score (ISS);

■ Revised Trauma Score (RTS);

■ Penetrating Abdominal Trauma Index (PATI);

■ Anatomic Profile (AP);

■ Trauma Score - Injury Severity Score (TRISS).

Original source

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):568-72; discussion 572-3.

Validation

Togawa S, Yamami N, Nakayama H, Mano Y, Ikegami K, Ozeki S. The validity of the mangled extremity severity score in the assessment of upper limb injuries. J Bone Joint Surg Br. 2005; 87(11):1516-9.

Other references

1. Kumar MK, Badole C, Patond K. Salvage versus amputation: Utility of mangled extremity severity score in severely injured lower limbs. Indian J Orthop. 2007; 41(3):183-7.

2. Helfet DL, Howey T, Sanders R, Johansen K. Limb salvage versus amputation. Preliminary results of the Mangled Extremity Severity Score. Clin Orthop Relat Res. 1990; (256):80-6.