Disappearance of Phantom Limb Pain During Cauda Equina Compression by Spinal Meningioma and Gradual Reactivation After Decompression

Pain in the Context of Sensory Deafferentation

Pain that accompanies deafferentation is one of the most mysterious and misunderstood medical conditions. Prevalence rates for the assorted conditions vary considerably but the most reliable estimates are greater than 50% for strokes involving the somatosensory system, brachial plexus avulsions, spinal cord injury, and limb amputation, with controversy surrounding the mechanistic contributions of deafferentation to ensuing neuropathic pain syndromes. Deafferentation pain has also been described for loss of other body parts (e.g., eyes and breasts) and may contribute to between 10% and upwards of 30% of neuropathic symptoms in peripheral neuropathies. There is no pathognomonic test or sign to identify deafferentation pain, and part of the controversy surrounding it stems from the prodigious challenges in differentiating cause and effect. For example, it is unknown whether cortical reorganization causes pain or is a byproduct of pathoanatomical changes accompanying injury, including pain. Similarly, ascertaining whether deafferentation contributes to neuropathic pain, or whether concomitant injury to nerve fibers transmitting pain and touch sensation leads to a deafferentation-like phenotype can be clinically difficult, although a detailed neurologic examination, functional imaging, and psychophysical tests may provide clues. Due in part to the concurrent morbidities, the physical, psychologic, and by extension socioeconomic costs of disorders associated with deafferentation are higher than for other chronic pain conditions. Treatment is symptom-based, with evidence supporting first-line antineuropathic medications such as gabapentinoids and antidepressants. Studies examining noninvasive neuromodulation and virtual reality have yielded mixed results.

Phantom phenomena in limb amputees – a review article

Amputation leading to the loss of a body part is associated not only with significant economic costs, but also serious consequences of medical and socio-psychological nature. It is the ultimate means to save a life or improve its quality. The most difficult challenges faced by amputees include accepting changes regarding their own physiognomy and the resulting life restrictions. The patient subjected to amputation is faced with an extremely difficult adaptation process, during which s/he should strive for a maximum degree of independence. Unfortunately, a large group of patients also struggles with various types of sensations and pain located within the lost limb − i.e., so-called phantom phenomena. This is a special group of phenomena of diverse nature, “located” within the lost limb. The occurrence of phantom limb syndrome in amputee patients is extremely common. This problem affects from 45% to even 98% of patients after amputation of one or both upper and lower limbs. The main purpose of this article is to describe phantom phenomena observed in patients after limb amputation in light of current literature. The definition, historical outline, types of phantom phenomena are presented, as well as hypothetical pathomechanisms, factors influencing the frequency and intensity of phantom phenomena and available treatment methods. The work was based on numerous text sources and the author’s own experience.

Phantom limb pain from spinal sarcoma: a case report

Phantom limb pain is a frequent sequela of amputation. A high prevalence of residual limb pain and back pain also exists among amputees. We present a case of a new-onset severe phantom limb pain resulting from a metastatic spinal mass in an 81-year-old patient with a history of malignant sarcoma and an old hip disarticulation amputation. The metastatic lesion, upon imaging, was found to involve the L3 vertebra and caused moderate compression of the thecal sac on the right and severe right lateral recess stenosis. After the mass was resected, the patient's phantom limb pain resolved. Our case report demonstrates that spinal metastatic pathologies may be a cause of phantom limb pain and should be included in the differential diagnosis of new-onset phantom limb pain or a change in phantom limb pain.

Postamputation pain: epidemiology, mechanisms, and treatment

Postamputation pain (PAP) is highly prevalent after limb amputation but remains an extremely challenging pain condition to treat. A large part of its intractability stems from the myriad pathophysiological mechanisms. A state-of-art understanding of the pathophysiologic basis underlying postamputation phenomena can be broadly categorized in terms of supraspinal, spinal, and peripheral mechanisms. Supraspinal mechanisms involve somatosensory cortical reorganization of the area representing the deafferentated limb and are predominant in phantom limb pain and phantom sensations. Spinal reorganization in the dorsal horn occurs after deafferentataion from a peripheral nerve injury. Peripherally, axonal nerve damage initiates inflammation, regenerative sprouting, and increased "ectopic" afferent input which is thought by many to be the predominant mechanism involved in residual limb pain or neuroma pain, but may also contribute to phantom phenomena. To optimize treatment outcomes, therapy should be individually tailored and mechanism based. Treatment modalities include injection therapy, pharmacotherapy, complementary and alternative therapy, surgical therapy, and interventions aimed at prevention. Unfortunately, there is a lack of high quality clinical trials to support most of these treatments. Most of the randomized controlled trials in PAP have evaluated medications, with a trend for short-term Efficacy noted for ketamine and opioids. Evidence for peripheral injection therapy with botulinum toxin and pulsed radiofrequency for residual limb pain is limited to very small trials and case series. Mirror therapy is a safe and cost-effective alternative treatment modality for PAP. Neuromodulation using implanted motor cortex stimulation has shown a trend toward effectiveness for refractory phantom limb pain, though the evidence is largely anecdotal. Studies that aim to prevent PA P using epidural and perineural catheters have yielded inconsistent results, though there may be some benefit for epidural prevention when the infusions are started more than 24 hours preoperatively and compared with nonoptimized alternatives. Further investigation into the mechanisms responsible for and the factors associated with the development of PAP is needed to provide an evidence-based foundation to guide current and future treatment approaches.