The Iraq-Iran war from 1980 through 1988 left more than one million dead or injured people.1 Of the 398,587 injured, 11,570 underwent lower limb amputation. Of these, 578 persons had amputation in both lower limbs.2
When determining the amputation level, many factors such as tissue viability, prosthetic options, gait dynamics, cosmetic aspect, and biomechanics of the residual limb are considered.3 Phantom limb sensation, phantom limb pain, and generalized residual limb pain are complicated feelings, probably maintained by afferent, central, and efferent dysfunction.4 Phantom limb sensation and pain are neuropathic perceptions in a portion of a limb that was amputated. Most amputees experience some degree of phantom limb pain and sensation, but the natural history generally shows a diminishing of these feelings in both frequency and intensity over the first few weeks to months after the amputation.5 The prevalence of phantom pain, defined as pain in the limb that is no longer present, has been reported to be as high as 85%, whereas the reports on the prevalence of residual limb pain vary from 10% to 13% at 2 years postamputation to 55% to 76% in longstanding amputees.6 Phantom limb sensation is nonpainful sensation perceived as emanating from the portion of the amputated limb.7 Its prevalence is reported to be as high as 79% in the study by Ehde et al., thus somewhat more prevalent than phantom limb pain (72%) and residual limb pain (74%). Amputation-related chronic pain, including pain in the phantom limb and residual limb, impairs function8,9 and is negatively correlated with employment.10–12 Back pain has been reported to affect 52% to 71% of amputees in the United States.
The primary aim of this study is to determine the prevalence and characteristics of phantom limb pain, phantom limb sensation, and spine pain and to evaluate their relevance to the various levels of amputation.
Participants were recruited from the pool of war victims who had undergone bilateral lower limb amputations from 1980 to 2006. In this study, all the available bilateral lower limb amputees (400 amputees) were invited by Janbazan Medical and Engineering Research Center to a recreational camp; of these 335 amputees participated. They were visited by three physiatrists. After obtaining participants' consent, questionnaires were completed. Inclusion criteria were as follows: 1) 6 or more months since lower limb amputation; 2) 18 years or older; and 3) war-related bilateral lower limb amputation. Exclusion criteria were perceptual and cognitive impairments, which would make the answers unreliable.
The questionnaire assessed a number of dimensions of phantom sensations, phantom limb pain and spine pain, course and level of amputation, and prosthesis use. Phantom pain- or sensation-related questions were divided into sections distinguishing the types of sensations, and respondents were asked to answer questions on each phenomenon. To facilitate participants' understanding of the pain categories, the types of pain and sensation were defined for them in the following ways. “Phantom limb pain” referred to painful sensation in the missing limb. “Phantom limb sensation” was defined as sensations in the missing limb that were not painful. The causes of amputation were asked from amputees or their associates; the level of amputation was determined by the physiatrists. Prosthesis use was evaluated during the previous 4 weeks. For amputees who decided not to use prostheses, we asked the reasons and then classified the answers based on the presence of residual limb pain, high weight of prosthesis, need for repair, and others. The participants were asked questions regarding cervical, thoracic, and low back pain.
DEMOGRAPHIC AND AMPUTATION HISTORY QUESTIONNAIRE
Participants were asked demographic questions including their gender, age, educational level, employment status, and marital status. They also answered questions specific to their amputation, including the date of their most recent amputation, the reason for the amputation, the level of amputation, and prosthesis use.
Present, worst, least, and average pain were assessed by means of an all-point numerical rating pain scale (0 = no pain; 10 = pain as bad as it could be). Intensity was classified into four categories: very mild (1–2), mild (3–4), moderate (5–6), and severe (7–10).
All war-related bilateral lower limb amputees throughout the country were invited by Janbazan Medical and Engineering Research Center to a recreational camp. Of the 400 bilateral amputees, 335 amputees participated in our study. After taking consent, three physiatrists interviewed and examined the participants and filled the detailed questionnaire. Information was analyzed and compared with similar literature.
DESCRIPTION OF PARTICIPANTS
The majority of participants in the sample were men (97.6%) and married. More than half of the participants (58.5%) reported an education of 12th grade or higher. Occupation, daily prosthesis use, and prosthesis wearing characteristics are listed in Table 1. The causes of lower limb injury leading to amputation are listed in Table 2. The most common level of injury was transtibial (53%), transfemoral (36%), and knee disarticulation (6%; Table 3). Many amputees complained of spine pain during the past 4 weeks. Most of them complained of low back pain (53%). Approximately 22% of amputees had neck pain, and 9% were suffering from thoracic spine pain. All participants were prescribed prostheses for both limbs. Approximately 21% of amputees did not wear prostheses during the past 4 weeks. The rate of prosthesis use avoidance is as follows: 62% in hip disarticulation (8 limbs), 21% in transfemoral amputation (51 of 238 limbs), 20% in knee disarticulation (9 of 43 limbs), and 6% in transtibial amputation (23 of 347 limbs).
PHANTOM LIMB SENSATION
More than three fourths of the sample (n = 273, 83%) reported that they experienced phantom limb sensation (Table 4). According to the table, only approximately 15% of the sample had persistent phantom sensation (described by always or often), and the majority of them (85%) complained of episodic phantom sensation. Phantom sensation intensity (bothersomeness) in less than 17% of the sample was severe. Approximately 82% transfemoral and 83% transtibial amputees experienced phantom sensation.
PHANTOM LIMB PAIN
Approximately two thirds of the sample (64%) reported that they experienced phantom limb pain (Table 4); approximately 18% of the sample experienced phantom pain more than 8 hr/day in the past 4 weeks; and the intensity of phantom pain was severe in only 13% of the sample. Approximately 65% transfemoral and 63% transtibial amputees experienced phantom limb pain.
The major purpose of our study was to quantify and specify the prevalence and characteristics of phantom limb sensation and phantom limb pain in war-related bilateral lower limb amputees and their relevance to various levels of amputation. In our investigation, approximately 83% of the sample experienced phantom sensation, the majority of them were episodic, and less than 17% of them experienced annoying sensations. Approximately two thirds (64%) of the sample were suffering from phantom pain. Phantom pain was less prevalent than phantom sensation, but approximately one third of the participants experienced moderate to severe pain. There was no difference between prevalence of phantom limb pain or sensation in transfemoral and transtibial amputations. Houghton et al.13 investigated 176 lower limb amputees and reported the prevalence of phantom limb sensation and phantom limb pain in 82% and 78% of participants, respectively. Jensen et al.14 reported the prevalence of phantom pain during first 6 months of amputation in about 59%. In the study by Wartan et al.15 on 590 British veteran amputees, phantom pain, phantom sensation, and residual limb pain were reported in 55%, 67%, and 56%, respectively. Dillingham et al.16 studied 14 amputees from the Persian gulf war and reported phantom pain in 64% of amputees. Douglas et al.17 reported the prevalence of phantom pain, phantom sensation, and residual limb pain in 61%, 79%, and 76% of lower limb amputees, respectively. In the study by Ehde et al. on 255 cases of lower limb amputees, 79%, 72%, and 74% reported phantom limb sensation, phantom limb pain, and residual limb pain, respectively, and finally in the study by Ephraim et al. involving 914 persons with limb loss, phantom pain, residual limb pain, and back pain were reported in 79.9%, 67.7%, and 62.3% of amputees, respectively. According to the aforementioned studies, the prevalence of phantom limb pain and phantom limb sensation were 55% to 80% and 67% to 82%, respectively, and in our study, the prevalence of phantom sensation was a bit more than previous studies. More than half of the amputees (62%) were suffering from back pain (53% low back pain). Low back pain was reported in 51% and 56% of transtibial and transfemoral amputees, respectively. Neck pain was reported in 22% of amputees, and there was no significant difference in the various levels of amputation. Most of the transtibial amputees wore prostheses (94). Despite the great percentage of limb loss, most amputees had a job (73.1%) and were married (97.6%).
There were some limitations to this study. This study focused only on war victims who are bilateral lower limb amputees and excluded single limb and upper limb amputees; thus, it was not necessarily representative of the population of persons with amputation and, therefore, may limit the generalization of the results. In this study, we tried to understand whether there were any increased percentages of phantom pain or sensation rate compared with single limb amputations, but according to the aforementioned literature that studied single limb amputees, we did not find any significant difference. Furthermore, some amputees might have exaggerated pain characteristics to take secondary gain, and it would be so difficult to determine these possibilities. Almost all patients received medication for phantom pain or sensation, but we did not exclude a very small minority of patients who did not receive any medication.
Phantom limb pain and phantom limb sensation are highly prevalent in war-related bilateral lower limb amputees, but only approximately 13% and 5% of them experienced severe (rating 7–10) phantom limb pain and phantom limb sensation, respectively. There is no relevance between the level of amputation and the rate of phantom limb pain or sensation. Furthermore, the rate of phantom pain or sensation did not increase in bilateral amputations compared with single limb amputations. Despite higher levels of limb loss, most amputees had a job and an active life. Spine pain is common in lower limb amputees, and 53% and 22% of participants complained of low back pain and neck pain, respectively, thus, this seems to be an important item needing attention in dealing these patients. Another survey is required to elucidate the impact of severe phantom pain and accompanying medical conditions on activities of daily living.
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