Predictive Factors for Failure of Limb Salvage in Blunt Leg Trauma Associated with Vascular Injuries.

INTRODUCTION: Blunt leg trauma is common; however, it is rarely associated with significant vascular injury. This study was undertaken to determine the risk factors attributed to failure of limb salvage in acute postoperative period in blunt leg trauma with vascular injuries after revascularization.
METHODS: A retrospective analysis was conducted of all patients with blunt leg trauma involving bone and soft tissue associated with vascular injuries. They were studied in terms of demographic data, associated comorbidities, mechanism of trauma, associated extra leg injuries, type and nature of bone fractures, soft-tissue injuries, nerve injuries, time of ischemia, Injury Severity Score (ISS), Mangled Extremity Severity Score (MESS), injured vascular segments, modality of vascular repair, modality of bone fixation, thrombosis at the site of vascular repair, complications, limb salvage failure, and mortality.
RESULTS: Vascular injuries were identified in 45 arterial segments and 9 popliteal veins among 31 patients. The patients were 93% male, with a mean age of 31 years. The MESS ranged from 6 to 11, and the ISS ranged from 9 to 41. The main pathology of the injured vessels was contusion/thrombosis in 28 legs, which were repaired by interposition-reversed long saphenous vein graft. Seven patients developed postoperative thrombosis and underwent thrombectomy/embolectomy. Failure of limb salvage occurred in seven limbs with no mortality.
CONCLUSIONS: Severe multi-segmental bone fractures, prolong ischemic time of >10 h, and MESS of ≥9 are significant predictors of limb loss in patients with blunt leg trauma in association with vascular injuries. Copyright:

INTRODUCTION

Blunt leg trauma is common. However, it is rarely associated with a significant vascular injury.[12] The high energy of crushing trauma can cause extensive tissue damage with detrimental outcome such as high morbidity and mortality.[3] Management of associated life-threatening injuries takes priority which might lead to delay in definitive vascular repairs with subsequent limb loss.[4]

Limb salvage attempts are possible in the majority of blunt lower-limb trauma.[56] However, the decision might be difficult. Therefore, several scoring systems were designed to assess the severity of limb injury and to guide the treating team for limb salvage or primary amputation.[178910] The Mangled Extremity Severity Score (MESS) is widely used because it is simple with high specificity and accuracy.[18] However, MESS cannot be used as the sole criterion for the decision for lower-limb amputation primarily without attempted salvage.[11121314]

The most important risk factor for early limb loss is failed revascularization which is time dependent.[156] Several studies have been explored the factors associated with failure of limb salvage following blunt leg trauma with vascular injury. The aim of this study was to determine the risk factors attributed to failure of limb salvage in acute postoperative period in blunt leg trauma with vascular injuries after trials of revascularization.

METHODS

A retrospective analysis was conducted of all patients with blunt leg trauma involving bones and soft tissues associated with vascular injuries managed at our center from January 2005 to March 2017.

Patients' medical records were reviewed for demographic data, associated comorbidities, mechanism of trauma, associated extra leg injuries, type and nature of bone fractures, soft-tissue injuries, nerve injuries, time of ischemia, Injury Severity Score (ISS), MESS, injured vascular segments, modality of vascular repair, modality of bone fixation, thrombosis at the site of vascular repair, complications, failure of limb salvages, and mortality during the short-term follow-up period, which was defined as the period necessary for healing of all wounds/amputation sites and patients referral for rehabilitation (1–6 months).

Patients with blunt leg trauma involving bones and soft tissues associated with vascular injuries were managed initially by a multidisciplinary team including general, orthopedic, vascular, plastic surgeons and radiologists. All patients had rapid assessment and stabilization according to the American Surgical Society guidelines for Advanced Trauma and Life Support at the emergency department.[15] Assessment of vascular injuries was conducted clinically looking for hard signs of vascular injuries (profuse arterial bleeding, expanding hematoma, hematoma with felt pulse, clinical signs of foot ischemia, and absent arterial signals distal to the injury by handheld Doppler) and soft signs (nature and site of injuries, reduced foot perfusion, hematoma, bleeding, and abnormal arterial signals by handheld Doppler). ISS and MESS were assessed for each patient. Based on the presence or absence of “hard” clinical signs of arterial injury, an early indication must be placed for immediate surgical exploration versus additional diagnostic interventions such as arteriography or computed tomography angiography (CTA).

On the operative table, patient stabilization and limb exploration were carried simultaneously. Proximal control was achieved through nonviolated area; intravenous heparin was given as indicated. The decision of limb salvage or primary amputation was assessed by the multidisciplinary team (orthopedic, vascular, and plastic surgeons).

External or internal bone fixation was deferred after revascularization. Vascular repair was performed according to the type of vascular injuries. Four-compartment fasciotomy was done for limbs with crushing injuries or prolonged ischemic time more than 6 h before revascularization. Immediate reconstructive procedures were performed to cover exposed bone or vessels. The integrity of vascular repair was re-assessed clinically at the end to ensure adequate foot perfusion (worm foot, normal capillary refill, palpation for distal pulses, and hand Doppler examination) supported with on table arteriogram (if foot perfusion was questionable). Patients were monitored in the intensive care unit in the immediate postoperative period (48 h). Patients were followed up by the multidisciplinary team until healing of all wounds and patient referral for rehabilitation. During rehabilitation period, the patients were followed through the orthopedic outpatient's clinic at regular intervals.

In consistent with our center policies, patients or their guardians received a full explanation of the initial management's plans, the possible complications, and anticipated functional outcome. Informed written consent was obtained for every individual procedure.

Limb salvage failure was defined as limbs ended with short-term secondary amputation. Short-term secondary amputation was defined as major amputation (above or below the knee) performed in the defined period of follow-up.

Bone fractures were classified according to Gustilo classification system for long bone.[16] In this study, bone fractures were grouped into tibial fractures if the tibia had open comminuted fracture at on site (proximal, mid, or distal part) and both bone (tibia and fibula) fractures if both bones had open comminuted fractures at one site (proximal, mid, or distal part). Severe both bone (tibia and fibula) fractures are referred to open comminuted fractures of both bones at two separate sites (proximal with/mid or distal parts). Soft-tissue injuries were grouped into contused/lacerated legs, crushed legs without gross soft-tissue loss, and crushed leg with gross soft-tissue loss.

The patients were divided into two groups based on major amputations after attempted revascularization: Group A with successful limb salvage and Group B with failure of limb salvage. Demographic and clinical risk characteristics of the two groups were compared using the IBM SPSS Statistics for Windows, version 22 (IBM Corp.). Data were described using frequency distribution and analyzed using Chi-square test. P < 0.05 was considered statistically significant.

RESULTS

Thirty-one patients with attempted limb salvage after blunt leg trauma with vascular injury were included. There were 29 males and 2 females, with an age ranging from 7 to 56 years. Nine patients (29%) were >30 years, whereas 22 (71%) were ≤30 years. The mechanisms of blunt injuries were motor vehicle related in 25 patients (80%), machine-related injuries in 3 patients (10%), and falling down in 3 patients (10%).

Isolated leg injuries were found in 16 patients (51.6%), whereas the rest of the patients had associated extra leg injuries (upper extremity/shoulder, chest, abdomen, pelvic, and contralateral limb). ISS scores ranged from 9 to 41. The mean ISS for the group was 22.65 ± 9.43 (22.25 ± 9.05 for successful salvage compared and 24.00 ± 11.330 for failed attempted limb salvages [FALSs]). Hard signs of vascular injuries were found in 23 legs (external profuse arterial bleeding in 13, ischemic limb in 6, and expanding pulsatile hematoma 4 patients). Preoperative arteriogram (before the adaptation of CTA) and CTAs were performed in 21 patients when suspected multiple leg vascular segment injuries in 17 patients and presence of soft signs of vascular injuries in 4 patients.

All bone fractures were compound comminuted of Gustilo IIIC; tibia was fractured in nine patients, both bones were fractured at proximal, mid, or distal end in 15, and severe both bone fractures at both ends in 7 patients. External fixations were used for 23 patients and internal fixation in 8 patients. Soft-tissue injuries were as follows: laceration/contusion in 9 patients, crushed without tissue loss in 11 patients, and crushing with tissue loss in 11 patients. Associated nerve injuries occurred in 18 legs; six of them were transected and they were repaired primarily, whereas the remaining 13 were contused.

There were 45 injured arterial segments with concomitant 9 popliteal veins. The majority of vascular injuries were contusion/stretching and thrombosis, whereas one popliteal artery, one tibio-peroneal-trunk (TPT), and two popliteal veins had lateral puncture wound by bony spikes, in addition to one completely transected TPT. In 30 legs, the popliteal/TPT or both were the main injured arterial segments with concomitant popliteal vein, anterior tibial artery, posterior tibial artery, and peroneal arterial injuries. Arterial repair was needed for all legs. Popliteal/TPT injuries were repaired for 27 legs by interposition-reversed long saphenous vein graft, in addition to one leg which had injured anterior and posterior tibial arteries without popliteal/TPT. Long saphenous veins were harvested from contralateral site. Vascular segment injuries and modality of repair are listed in Table 1.

Table 1

Vascular segment injuries and repairs

Injured vascular segment	Number	Interposition vein graft	Direct repair	Ligation
Popliteal A	12	11	1	0
TPT	10	8	2	0
Popliteal artery+TPT	8	8	0	0
Anterior tibial artery	8	5	0	3
Posterior tibial artery	5	4	0	1
Peroneal artery	2	o	0	2
Popliteal vein	9	7	2	0

TPT: Tibioperoneal trunk

On the table, postoperative thrombosis occurred for 7 legs, for which revision of vascular repair was needed (6 arteries and one vein); 3 of the revised anastomosis needed proximal extension of vessels debridement, 2 needed distal extension of vessel debridement, 1 repaired artery, and 1 vein developed proximal anastomotic thrombosis that needed removal of local thrombus and anastomotic revision without vessel's debridement. Two of the revised arterial repairs had recurrent thrombosis for the second time in the postoperative period (24–48 h).

Amputation was needed for 7 limbs (4 above the knee and 3 below the knee). The causes of amputation were arterial revascularization-related problems in 4 patients (2 early re-thrombosis in addition to third thromboses that occurred 5th postoperative days and disruption of the anastomosis due to infection with bleeding at 9th postoperative day), two of the amputations were related to life-threatening sepsis, and one amputation was performed secondary to failed reconstruction and extensive muscle debridement. Complications are listed in Table 2.

Table 2

Complications of attempted limb salvages

Complication	n
Superficial wound infections	8
Deep infection/acute osteomyelitis	3
Myoglobin urea	6
Systemic sepsis/SIRS	2
Acute renal failure (transient)	3
Failed flap	3
Donor site infection (split thickness skin graft)	5
External fixation pin-tract infection	6
Chronic osteomyelitis	3
Arterial thrombosis	3
Bleeding due to arterial anastomotic disruption	1
Limb salvage failures	7

SIRS: Systemic inflammatory response syndrome

The demographic and clinical characteristics in relation to FALS are listed in Table 3. In this study, patient's age, hypotension (<90 mmHg) on arrival, associated extra leg injuries, soft-tissue injuries, injured arterial segments, and nerve injuries were not found to be significantly associated with FALSs.

Table 3

Demographic and clinical risk characteristics in relation to failed attempted limb salvage

Risk factors	Failed attempted salvages		Total, n (%)	P
	No, n (%)	Yes, n (%)
Age of patients (years)
≤30	18 (81.8)	4 (18.2)	22 (71)	0.384
>30	6 (66.7)	3 (33.3)	9 (29)
Mangled extremity severity score
≤8	22 (88)	3 (12)	25 (80.6)	0.014
≥9	2 (33.3)	4 (66.7)	6 (19.4)
Ischemic time (h)
≤10	20 (90.9)	2 (9.1)	22 (71)	0.012
>10	4 (44.5)	5 (55.6)	9 (29)
Arterial hypotension (<90 mmHg): Yes	14 (82.4)	3 (17.6)	17 (54.8)	0.671
Associated extra leg injuries	12 (80)	3 (20)	15 (48.4)	1.00
Fractured tibia/both bones at one end	22 (91.7)	2 (8.3)	24 (77.4)	0.002
Severe both bones at the two ends	2 (28.6)	5 (71.4)	7 (29.0)
Contusion/laceration	8 (88.9)	1 (11.1)	9 (29)	0.639
Crushed with/without lost flab	16 (72.7)	6 (27.3)	22 (71)
Popliteal artery and tibioperoneal injury	6 (75)	2 (25)	8 (25.8)	1.00
Popliteal artery injury	16 (80.0)	4 (20)	20 (64.5)	1.00
Tibioperoneal trunk injuries	13 (72.2)	5 (27.8)	18 (58.1)	0.667
Posterior tibial artery	2 (40)	3 (60)	5 (16.1)	0.062
Anterior tibial artery injuries	5 (62.5)	3 (37.5)	8 (25.8)	0.335
Popliteal vein injuries	6 (66.6)	3 (33.3)	9 (29)	0.384
Arterial and venous injuries	6 (66.6)	3 (33.3	9 (29)	0.384
Arterial thrombosis/disruption
No	20 (87)	3 (13.0)	23 (74.2)	0.053
Yes	4 (50)	4 (50)	8 (25.8)
On table thrombosis (arterial or venous)	5 (71.4)	2 (28.6)	7 (22.6)	0.642
Bone fixation before vascular repairs	13 (81.2)	3 (18.8)	16 (51.6)	0.685
Bone fixation after vascular repair	11 (73.3)	4 (26.7)	15 (48.4)
Nerve injury	15 (83.3)	3 (16.7)	18 (60)	0.392
Fasciotomy	14 (82.4)	3 (17.6)	17 (54.8)	0.671

The following factors were found to be associated significantly with FALSs: MESS ≥9, time of ischemia of >10 h, and severe both bone (tibia and fibula) fractured proximally and distally. None of the patients with attempted salvage died.

DISCUSSION

Lower extremity trauma with concomitant orthopedic and vascular injury is associated with a high degree of limb loss. Blunt leg traumas with vascular component are uncommon serious injuries. The most important risk factor for early limb loss is failed revascularization.[156171819] Scoring systems were proposed to guide the treating team in making the decision for salvage or amputation.[178910] However, most of the scoring systems had been reported to be less reliable than they were stated once devised. Therefore, they cannot be used as the sole criterion for primary amputation decision.[1114] The clinical judgment of a multidisciplinary team with the help of a scoring system might be the prime guide to save or amputate the limb.[616] Improved techniques of microsurgery, fracture stabilization, bone reconstruction, and vascular techniques had made limb salvage possible.[20] Early reconstruction and internal fixation might be appropriate.[2122] Although delayed wound closure was used as the standard treatment, it may be a cause of additional tissue infection.[22232425]

In this study, patients had attempted limb salvage after exploration by a multidisciplinary team approach. In agreement with others, motor vehicle-related accidents were the major causes of blunt leg trauma with vascular component.[214]

Limbs with MESS score of ≥9 showed a significantly high rate of failed attempted salvages in comparison to limb with MESS score of ≤8 (P < 0.05). A score of 9 may be the cutoff point for attempted limb salvages.

Vascular injury can have devastating consequences in patients, as irreversible ischemia can occur in as short as 6–8 h. However, period of reversible tissue ischemia is variable depending on the state of collateral circulation and the extent of injuries. In this study, ischemic time of >10 h had worse prognosis for limb salvage compared to legs with ischemic time of ≤10 h (P < 0.05).

Bones fracture (tibia and fibula) at ≥2 separate sites demonstrated a significant difference in limb salvage failure compared to other patterns of fractures (P < 0.05). The nature of bone fractures had been suggested to be associated with poor outcome.[26] In Gustilo classification system for long bone fractures, there was a wide diversity of the injury severity within each specific group.[27] Severe comminuted fractures had more complications and longer time for healing than simple ones.[111] Blunt popliteal arterial injuries with severe comminuted bone fractures can predict lower-limb amputations.[28] An amputation rate of 29% was reported for blunt leg trauma involving concomitant both bone fractures (tibia and fibula) and popliteal artery injuries.[2] The healing capacity is impaired with increasing displacement of fractured fragments and increased degree of fragmentations.[29]

The rate of failed attempted limb salvage in association with different segments of arterial injuries showed no significant difference in this study. The pathologies of 28 injuries to the popliteal artery and TPT were contusion/thrombosis. However, only one popliteal and one TPT had lateral injuries by bony spikes, in addition to one completely transected TPT. The mechanisms of arterial injuries in blunt trauma are as follows: traction/avulsions/thrombosis, entrapment, and penetration by bone fragments resulting in lateral punctures or complete transection. Isolated segment can be injured more likely with low-energy penetrating trauma, while high-energy blunt trauma can lead to long segment of stretching, contusion, and thrombosis.[1730] The extent of such injuries can be underestimated on gross appearance, especially when dealing with popliteal/TPT injuries. The extent of wall contusion and intimal injuries was underestimated by our initial judgments which might be explained the immediate thrombosis that occurred to 5 repairs in this group of patients, where they needed further refreshment and debridement of the injured contused vessels proximally or distally.

Patients with popliteal arterial injuries due to blunt trauma had a 2.6-fold increased risk for amputation compared to other arterial injuries of the extremities.[2831] Furthermore, amputation rate of 100% was reported secondary to popliteal trifurcation injuries.[32]

Concomitant injuries to tibial arteries were not found to be associated with increased risk for failed attempted limb salvage in our study, contrary to the reported increased risk for failed attempted limb salvages (secondary limb amputation) due to injuries involving tibial arteries.[192133]

Popliteal vein injuries occurred in 29% of blunt leg trauma in this study. The rate of venous injuries was high in comparison to that reported with blunt trauma of the legs by studies.[2] However, venous injuries did not contribute to significant difference in relation to failed attempted limb salvages. Although venous repairs were reported to have good long-term patency,[34] published data did not support our finding, where a combination of arterial and venous injuries was reported to be associated with higher amputation rate compared to arterial injuries without concomitant venous injuries.[233]

Patient's age, nerve injuries whether contusion or transection, presence of shock on arrival to hospital, type of soft-tissue injuries, and associated extra leg injuries did not contribute significantly to worse outcome related to attempted limb salvages. However, nerve injuries were considered important risk factors for poor functional and long-term disability outcome.[791119]

Patient's age used to be part of the scoring systems and important risk factors for primary amputation.[181130] However, others argue against the importance of age as risk factor for amputations.[31333536] In this study, 71% of patients were young ≤30 years of age; therefore, the results should be interpreted in that context.

ISSs are not predictive of the functional recovery of successfully salvaged limbs,[373839] and they could not be used as the sole criterion in clinical practice to go for primary amputation.[11121314] There was no mortality among our study group.

Limb salvage was achieved in 77.2% of injured legs in this study which was comparable to what had been reported in blunt trauma with associated vascular component.[182240] Failed revascularization was responsible for 4 out of 7 amputations. However, failed revascularization, sepsis, and failed soft-tissue managements were the main factors responsible for secondary lower-limb amputation. The major risk factors responsible for failed attempted limb salvages in this study were due to the extent and nature of bone injuries, prolonged ischemia >10 h, and high MESS ≥9. However, the limited number of patients in this study, the relative short period of follow-up, long-term rehabilitation coasts, and the lack of functional outcome data on the salvaged limbs constituted the limitation of this study.

CONCLUSIONS

Severe multi-segmental bone fractures, prolong ischemic time of >10 h, and MESS of ≥9 are significant predictors of limb loss in patients with blunt leg trauma in association with vascular injuries.

Research quality and ethics statement

This study was approved by the Institutional Review Board of Jordan University of Science and Technology. The authors followed applicable EQUATOR Network () guidelines during the conduct of this research project.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.