An objective value obtained from any of the limb salvage scoring systems–LSSSs used to help clinicians decide when to attempt limb salvage and when to proceed directly to amputation.
The MESS, NISSSA, and HFS-97 all heavily weigh the initial neurological examination, and assume that an acute sensory impairment correlates with diminished limb-salvage capacity and that the initial examination demonstrates the final deficit. That said, ischaemia, contusion, stretch, or compression can cause transient neurological injury. In the LSI, the neurological deficit is scored based on anatomical nerve findings.
The ideal trauma limb-salvage index should be:
100% sensitive–all amputated limbs with trauma limb-salvage scores at or above the scoring system’s threshold, and
100% specific–all salvaged limbs with trauma limb-salvage scores below the threshold.
Perfectly accurate. A high specificity would ensure that few salvageable limbs are incorrectly assigned a score above the decision threshold. High sensitivity limits inappropriate delays in amputation when the limb is not salvageable.
Meta-analysis indicates that LSSSs have limited usefulness and can’t be the sole criterion for amputation decisions; most lack sensitivity–and thus fail to support LSSS scoring as a predictor of amputation, despite high specificity. The high specificity of the scores confirms that low scores could be used to predict limb-salvage potential.
Scores at or above the amputation threshold should be used cautiously when deciding the fate of a lower extremity with a high-energy injury.
Mangled extremity scoring systems
• Hannover Fracture Scale-97–HFS-97
• Limb Salvage Index–LSI
• Mangled Extremity Severity Score–MESS
• Nerve Injury, Ischemia, Soft-Tissue Injury, Skeletal Injury, Shock, and Age–NISSSA Score
• Predictive Salvage Index–PSI
Synonym Mangled extremity score