Vascular Trauma in the Extremities: Factors Associated with the Outcome and Assessment of Amputation Indexes

Abstract

Background: Traumatic vascular injury in the extremities may be associated with a low mortality rate but can lead to limb loss that seriously affects patients' functionality. Multiple scoring systems have been designed to evaluate the prognosis, but none are 100% predictive. The management of traumatic vascular injury remains challenging and depends mostly on the surgeon's experience.

Objectives: We identified the risks associated with limb loss and further investigated the utility of current amputation indexes.

Methods: We retrospectively reviewed 53 cases of traumatic vascular injury in the extremities at a tertiary referral medical center over the past ten years (January 2011-December 2020). The mangled extremity severity score (MESS), limb salvage index (LSI), and predictive salvage index (PSI) were used to assess the traumatized limbs. The injury characteristics and outcomes were evaluated using regression analysis.

Results: The incidence of limb loss was 20.8% (n = 11), and open fractures were the most related factor. Extensive involvement of soft tissue, vascular injury combined with tibia or fibula fractures, initial shock status, and the amount of transfusion were associated with limb loss.

Conclusions: Our study identified the risk factors and clinical utility of MESS, PSI, and LSI. While both LSI and PSI had acceptable diagnostic accuracy, amputation should be decided based on a variety of criteria and clinical features. Salvaging any limb that has not become apparently futile seems logical, yet the presence of certain factors may suggest a worse outcome.

Keywords: Amputation index; Mangled extremity; Vascular trauma.

Figure 1

Diagnostic and treatment algorithm for vascular injury associated with extremity trauma. This figure summarizes the preoperative assessment and treatment protocol for patients with vascular injuries in the traumatized limb. A fasciotomy should be performed whenever a tense compartment is present. * Confronting an extremely bony dislocation, a damage control orthopedic surgery with temporary fixation may be performed prior to vascular repair to maintain stability at the anastomosis site. CTA, computed tomography angiography; PTEF, polytetrafluoroethylene.

Figure 2

The Kaplan-Meier survival rate analysis of the 30-day cumulative survival of traumatized limbs associated with open fractures and shock. (A) Significantly lower incidence of limb salvage in extremities with an open fracture (red dashed line) than in those without an open fracture (blue dashed line) is demonstrated. (B) Patients with an initial shock status (red dashed line) lose their limbs more rapidly than those without (blue dashed line). The associated confidence interval (CI) is plotted in a continuous line with the same color as the risk factor.

Figure 3

Receiver operating characteristic (ROC) curves of the accuracy concerning amputation indexes. The ROC curves of LSI (A), M-LSI (B), MESS (C), M-MESS (D), PSI (E), and M-PSI (F) in discriminating amputation by a cut-off value are plotted in this figure. The traumatized limb was evaluated with both original and modified (M-, the time factor was excluded) amputation indexes. The cut-off point was retrieved using Youden index analysis of an individual amputation index. Sensitivity is defined as the proportion of amputees with a score above a given value, whereas specificity is the percentage of patients in the limb salvage group having a score below the index’s set point. The AUC increased with the modified amputation index. Both the original (A) and modified (B) LSIs can better discriminate if a limb should be amputated or salvaged. AUC, area under the receiver operating characteristic curve; LSI, limb salvage index; MESS, mangled extremity severity score; PSI, predictive salvage index.