Background & Aims

Phantom limb pain (PLP) is defined as a painful sensation referring to the missing limb and prevalence can be estimated in up to 80% of all patients after limb amputation. The onset of PLP is variable, with most occurring soon after amputation. Pain intensity is frequently reported as moderate to severe with 10% of amputees reporting severe pain more than 6 months after surgery. Pain may be related to certain position or movement of the phantom, and may be exacerbated by physical factors like pressure on the residual limb or emotional factors like stress. PLP is more intense in the distal portions of the phantom and has qualities of neuropathic pain such as burning, stabbing, pricking pain. Telescoping i.e. the retraction of the phantom towards the amputated limb has been reported in up to 30% of patients. PLP affects patients’ quality of life with 25-50% reporting severe pain-related impairment.

Methods

We describe a case of a 25 year old female who was admitted to Khoo Teck Puat Hospital for polytrauma from a road traumatic accident. She suffered the following injuries: traumatic subarachnoid haemorrhage (SAH) and subdural haemorrhage (SDH), left humerus open fracture s/p fixation, right tibia shaft and right ankle fracture s/p fixation, left upper cervical ICA dissection s/p stenting, left above knee amputation (AKA) with subsequent revision of stump. She was referred to the Pain Clinic 4 years after her traumatic AKA with complaints of phantom limb pain, she reported burning and stabbing pain in the missing limb which occurred daily and affected her sleep and quality of life. She was also diagnosed with hyper-vigilance and heightened startle response secondary to the accident not amounting to full fledged post traumatic stress disorder (PTSD) and anxiety.

Results

She was started on gabapentin which was titrated to response up to 1800mg/day and nortriptyline 10mg once nightly was added. She was commenced on mirror therapy which provides the impression of viewing the amputated limb, which lead to less pain and better movement in the amputated limb. She was seen by psychiatry and started on escitalopram 15mg once nightly as well as psychology for relaxation strategies and mindfulness. She was also reviewed by occupational therapy regarding optimal fitting of her prosthesis. Through multi-disciplinary team care comprising pain physician, psychiatry and psychology, occupational and physical therapy, she had marked improvement in her PLP and was able to function independently in the community and with her activities of daily living.

Conclusions

Peripheral and central factors both contribute to phantom limb pain. Peripheral factors result from abnormal nociceptive input from the residual limb or ectopic discharge from a stump neuroma. Central factors are due to central sensitisation with increased excitability of the dorsal horn neurons, reduction of inhibitory processes and reorganisation of the somatosensory cortex. Psychological factors do not seem to contribute to the causation but may instead affect the course and severity of the pain. Randomised controlled trials for the treatment of PLP are lacking. Sodium channel blockers (gabapentin and pregabalin) and tricyclic antidepressants are the treatments of choice. Ketamine, topical lignocaine and capsaicin have been shown to reduce PLP. Mirror therapy has also been shown to reduce PLP and enhance ability to move the phantom limb.

References

Erlenwein J, Diers M, Ernst J, Schulz F, Petzke F. Clinical updates on phantom limb pain. Pain Rep. 2021; 6(1): e888
Flor H. Phantom-limb pain: characteristics, causes, and treatment. Lancet Neurol. 2002; 1(3): 182-9

Presenting Author

Christine Ong

Poster Authors

Hui Jing Christine Ong

MD

Khoo Teck Puat Hospital

Lead Author

Tut Choon Low

MBBS

Lead Author

Topics

  • Specific Pain Conditions/Pain in Specific Populations: Pain in Amputees