Prevalence and Predictors of Lower Limb Amputation in the Spinal Cord Injury Population
Background: Despite limited data demonstrating altered hemodynamics in the lower extremities (LEs) among the population with spinal cord injury (SCI) and increased frequency of peripheral arterial disease (PAD), epidemiologic data are limited for amputations, a potential consequence. This study investigates the association of amputation due to vascular complications as a secondary outcome measure within the SCI population.
Methods: A retrospective cohort study was performed within a veteran population with SCI at a US Department of Veteran Affairs hospital to determine the prevalence of limb loss. We hypothesized that premorbid SCI increased the likelihood of LE amputation.
Results: Of 1055 charts reviewed, 91 (8.7%) patients had an amputation, 70 (76.1%) had a dysvascular etiology. Transfemoral amputations were the most common level (n = 53) of amputation. Our results showed a positive correlation between the completeness of injury and the prevalence of amputation.
Conclusion: There is an increased frequency of amputation among the veteran population with SCI compared with that of the general US population. Amputations frequently occur at more proximal levels with motor complete injuries. Studies using a larger population and multiple centers are needed to confirm this alarming trend.
Injury by Impairment Scale Level
Forty-nine (11.5%) of 426 patients with AIS level A SCI had undergone amputation. In order of prevalence, 23 (46.9%) were unilateral TFA, 17 (34.6%) were bilateral TFA, 10.2% were partial foot/toe, 4.1% were unilateral TTA, and 4.1% were a TTA/TFA combination. Both hip and knee disarticulations were classified in the TFA category.
Sixteen (13.0%) of 123 patients with AIS level B SCI had undergone amputation; 5 (31.3%) of those amputations were unilateral TFA, 6 (37.5%) were bilateral TFA, 3 (18.8%) were partial toe or foot, and 1 (6.3%) was for unilateral and bilateral TTA each.
Twelve (8.4%) of 143 patients with AIS level C SCI had undergone amputation: 6 (50.0%) were bilateral TFA; 3 (25.0%) were unilateral TFA; and 3 (25.0%) were unilateral TTA.
Fourteen (3.9%) of 356 patients with AIS level D SCI had undergone amputation. Of those 6 (42.9%) underwent a partial foot/toe amputation; 5 (35.7%) had undergone a unilateral TTA, and 1 (7.1%) underwent amputation in each of the following categories: bilateral TTA, unilateral TFA, and bilateral TFA each.
None of the 7 individuals with AIS E level SCI had undergone amputation.
Health Risk Factors
Of the 91 patients with amputation, the majority (81.3%) were either former or current smokers. Thirty-six percent of those who had undergone amputation had a diagnosis of DM, while only 21% of those who had not undergone amputation had a diagnosis of DM.
At the time of their annual examination 532 patients had a diagnosis of HTN while 523 patients did not. Among patients with amputations, 59 (64.8%) had HTN, while 32 (35.2%) did not. Of the 964 patients without amputation, the prevalence of HTN was 50.9%
.Of 1055 patients with SCI, only 103 (9.8%) had a PAD diagnosis, including 38 (41.9%) patients with amputation. Just 65 (6.7%) patients with SCI without amputation had PAD (P < .001). PAD is highly correlated with dysvascular causes of amputation. Among those with amputations due to dysvascular etiology, 50.0% (35/70) had PAD, but for the 21 amputations due to nondysvascular etiology, only 3 (14.3%) had PAD (P = .004).
