Cross-sectional study of alteration of phantom limb pain with visceral stimulation in military personnel with amputation.

INTRODUCTION Phantom limb pain is pain perceived in a region of the body that is no longer present. It occurs in 50 to 80 percent of all people with amputation [1]. Descriptions of phantom limb pain by patients are frequently referred to as knifelike, burning, sticking, throbbing, or shocking sensations [2]. The pain is often episodic in nature and of variable duration [3]. The number of military personnel with amputation in the United Kingdom has risen markedly as a result of the recent conflicts in Iraq and Afghanistan. This is due to the pattern of injuries caused by improvised explosive devices and improvements in trauma care that have resulted in a greater survival rate [4]. While phantom limb pain is a well-recognized phenomenon [5], clinical experience has suggested that the augmentation of phantom limb pain with visceral stimulation is an issue for many military personnel with amputation (visceral stimulation being the sensation of the bowel or bladder either filling or evacuating). However, the prevalence of this phenomenon is not known. The aim of this study was to investigate the prevalence of the alteration in phantom limb sensation with visceral stimulation in military personnel with amputation and the effect that visceral stimulation has on phantom limb pain intensity. METHODS A questionnaire was designed to assess the severity of phantom limb pain and how it altered from the patient's baseline with visceral stimulation using a pain visual analog scale (VAS), which was graded from 0 (no pain) to 10 (most severe pain imaginable). The patient group was military inpatients at Defence Medical Rehabilitation Centre (DMRC) Headley Court who had undergone amputations, secondary to traumatic injury, of one or both of their lower limbs. This was a cross-sectional study, including all patients admitted to DMRC Headley Court over a period of 2 mo. Patients were offered the questionnaire during the hospital admission assessment by the admitting doctor. [FIGURE 1 OMITTED] All patients were treated by the same multidisciplinary rehabilitation team. This included regular reviews by pain specialists as well as extensive postamputation counseling. Each patient was started on an initial postoperative analgesia pathway of opiate analgesia as well as being loaded with pregabalin. Medication dosage was titrated to patient response, and further amendments to medications were undertaken if required (Figure 1). Occupational therapists were involved in the treatment of all patients with the use of various therapies. A Graded Motor Imagery treatment plan consisting of a three-stage synaptic exercise process was used. This involved left/right discrimination, imagined movements, and mirror therapy with active range-of-motion exercises for 1 h a day for a minimum of 6 wk. Patients recorded the presence and intensity of phantom limb pain at rest using the pain VAS. They also recorded whether and how this pain altered with a need to micturate or micturition, and/or a need to defecate or defecation, again using a pain VAS. Time since amputation, level of amputation, and medications used were also recorded. Patients were asked whether any of the medications or any other treatments had helped with this pain, whether the pain had improved over time, and to describe the pain in their own words. Ethical approval was granted for this study by the Ministry of Defence Research Ethics Committee (MODREC). RESULTS All 75 patients approached completed the questionnaire. Their average age was 26.3 yr (range 18-42 yr, standard deviation 5.2). There were 74 male patients and 1 female patient. The presence of phantom limb pain at baseline was reported in 64 of 75 (85%) of cases. The mean VAS in these 64 cases was 3.6 [+ or -] 2.1. An alteration of phantom limb pain following visceral stimulation was reported by 42 of 75 (56%) patients. …