Chronic regional pain syndrome (CRPS) is characterized by ongoing disproportionate sensory, vasomotor, sudomotor, and trophic changes that occur in a region of the body, in no specific dermatome. It is a diagnosis of exclusion and has variable progression. The Budapest criteria provide the most sensitive and specific guidelines for the diagnosis of CRPS.1,2 According to these criteria, there must be at least one of the following symptoms in 3 of 4 of the above categories for clinical diagnosis: hyperalgesia, allodynia, skin color and temperature change, edema, decreased range of motion, motor dysfunction, trophic changes, tremor, or dystonia.1–3 Additionally, there must be 1 sign in 2 of the categories at the time of clinical presentation and no other plausible diagnosis.1–3 The criterion for research purposes differs from the clinical criterion by requiring at least one of the above symptoms in each of the categories and 1 sign in 2 or more of the categories.3
There are 2 types of CRPS: type 1 is not associated with known nerve damage, while type 2 is suspected when there is an inciting event causing nerve damage such as trauma or surgery.1–3 Treatment of CRPS is aimed at improving functionality and desensitizing the inappropriate signaling by restoring balance in the central nervous system through drugs, interventional regional techniques, and psychological therapy.3
We describe a case of a 59-year-old man who presented 7 months after coronary artery bypass surgery with symptoms and signs of truncal CRPS. After pharmacologic and regional block treatments failed, the patient underwent a trial of a spinal cord stimulation (SCS) with subsequent >90% relief of his pain and improvement in his daily life.
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A 59-year-old man with a history of coronary artery disease presented with persistent bilateral axillary pain after coronary artery bypass. His pain started 2 months after surgery initially beginning in the left axilla and subsequently spreading to his back, scapula, and contralateral right axilla over a period of 5 months. He described this pain as burning numbness that was deep, stabbing, and constant in nature with extension into the bilateral axilla crossing to midclavicular line, rated at 7–8/10. His initial regimen included oxycodone/acetaminophen 7.5/325 mg 3 times per day and pregabalin 75 mg twice per day.
His condition had intensified since onset with worsening hyperesthesia with movement and light touch. He complained of allodynia to the point that wearing a shirt and putting on deodorant was barely tolerable. He described waxing and waning erythema, and subjective swelling of his chest wall from the midaxillary line to midclavicular line with the associated dried skin of his chest wall, decreased sweating, and decreased ability to raise his arms. These signs and symptoms are shown in the Figure. In addition, the patient relayed he could not exercise and was having relationship problems due to his depression and debilitation. Physical examination revealed allodynia bilaterally from the third to the eighth intercostal spaces, greater on the left side and erythematous changes in these distributions compared to the abdomen and shoulders. At this time, he was diagnosed with type 1 CRPS of the trunk.1,2
Over the course of the next 14 weeks, treatment from our pain clinic consisted of bilateral paravertebral blocks performed at the level of the fifth and sixth thoracic vertebral bodies and optimization of the patient’s pharmacologic regimen. The paravertebral blocks were performed with local anesthetic and steroid 2 weeks after initial consult. Medical optimization included increasing his pregabalin to the maximum daily dose of 300 mg and initiating naproxen 500 mg twice daily, desipramine 20 mg at night, and venlafaxine 75 mg daily; we also attempted to wean his oxycodone to 5 mg daily.
Despite the above treatments, the patient experienced increased sensitivity to pain, subcutaneous swelling of the chest wall, increased frequency of chest wall erythema, and inability to wean from opioids. This resulted in the patient resorting to increased alcohol intake for coping with pain and depression, which had significant effects on the patient’s marriage. Given the patient’s debilitation and lack of improvement, a SCS trial was performed 10 months after onset of symptoms.
Using fluoroscopic guidance, 2 introducer needles were placed in the posterior epidural space using a loss of resistance technique at the T10/11 level. Two 16-contact cylindrical SCS leads were advanced in the posterior epidural space with the top contact of 1 lead right paramedian at the level of the seventh cervical vertebral body, and the top contact of the second lead was positioned left paramedian at the level of the third thoracic vertebral body. Stimulation was concordant along the entire right upper extremity and left flank corresponding to the patient’s previous pain description. Conventional stimulation using continuous stimulation cycle and alternating programs using 60 or 70 Hz and between 7.4 and 12.0 mA were used for the trial. During the trial, the patient reported >75% improvement in bilateral chest wall and bilateral scapular pain and denied the need for any opioids after 1 week.
Permanent SCS lead and generator placement occurred in the operating room with monitored anesthesia care for comfort, 12 months after the onset of symptoms. The Boston Scientific Spectra System device was internalized, with generator placement in patient’s subcutaneous tissue in the right flank. At 2-week follow-up, the patient continued to be satisfied with his relief, stating >90% relief of his CRPS pain complaints and described no complications. At 6-week follow-up, the patient sustained >90% pain relief and had started an exercise regimen. For programming, he continued to use the same programming (conventional stimulation at 60–70 Hz and between 7.4 and 12.0 mA) as during the trial. He remained off opioids, taking only venlafaxine. He stopped using alcohol to cope and reported improvement in his depression and marital relationship.
The pathophysiology of CRPS is multifaceted with symptoms implicating the involvement of the immune and autonomic, central, and peripheral nervous systems. One theory postulates decreased sympathetic outflow to the affected region resulting in dysfunctional blood flow to the area and increased nociceptive firing. The potential treatments of CRPS include blocks, psychotherapy, drugs, occupational therapy, and progressive stimulation.3
The first randomized controlled trial investigating SCS for treatment of CRPS by Kemler et al4 demonstrated significant relief of pain with SCS and physical therapy combined in 39% of patients at 6 months after placement compared with physical therapy alone. In 2008, Kemler et al4 showed a decreased effectiveness of SCS in patients after 5 years; at this time, the symptom relief was equal to physical therapy alone.5 Despite this, 95% of the patients reported they would undergo repeat implantation due to significant pain relief.5
There are multiple studies which show that SCS is a cost-effective long-term treatment for patients with chronic pain syndromes, including CRPS.5–11 In 2013, Geurts et al7 demonstrated long-term pain treatment in 63% of patients defined by >30% pain reduction over 12 years. A prospective clinical study by Harke et al9 showed long-term benefit of SCS in patients with upper limb CRPS type 1 through increased fist grip strength after 35 months. The ACCURATE trial comparing dorsal root ganglion (DRG) versus SCS stimulation in patients with CRPS in the lower extremities found 53.3% of subjects receiving SCS had success of pain relief at 12 months as compared to 79.3% in the DRG group.6 While this trial suggests that DRG is more efficacious in the treatment of CRPS or causalgia, DRG would not have been a suitable choice for our patient due to the symptoms stemming from multiple spinal levels and thoracic placement being off-label for DRG. Currently, there is an ongoing prospective randomized, double-blind, and placebo-controlled crossover trial by investigating the effects of 5 different SCS modalities with pain reduction as the primary outcome and temperature asymmetry as the secondary outcome measure; thus, the future prospects for expanding and optimizing stimulation as an analgesic modality are abundant.10
It is hypothesized that SCS works by activating the dorsal columns and dorsal horn of the spinal cord and suppressing the efferent sympathetic nervous system output and inhibitory interneurons.3,12,13 Alleviation of symptoms is dependent on thoughtful and specific lead placement based on the anatomy of the spinal cord.14 Dermatomal mapping demonstrates that cervical levels, C3–C7, supply the arm and axilla.3 The fasciculus cuneatus corresponds with the upper body and extremities and is the most lateral tract within the dorsal column. It is for these reasons, we placed our lead at C7 to the right of midline, and ipsilateral with the right scapular and axillary pain, and the other lead was placed at T3 to the left of midline, and contralateral to the truncal symptoms. With this lead placement, there is inhibition of signals from the ascending bilateral dorsal columns to cover our patient’s truncal and right upper extremity symptoms. Additionally, lateral placement of the leads may inhibit signaling from the bilateral spinothalamic tracts.
Our case report is an example of how precise lead placement can provide full coverage for affected areas by manipulating the input and output of the contributing spinal cord tracts. Truncal and unilateral limb CRPS may be favorable for treatment with SCS when other treatment modalities have failed, as shown in this case report. More prospective randomized controlled trials are needed to determine the success rate, optimal timing of placement, and long-term benefits of SCS as a standard treatment for truncal CRPS.
Name: Lauren M. Poe, DO.
Contribution: This author helped write and edit the manuscript.
Name: Christopher M. Sobey, MD.
Contribution: This author helped write and edit the manuscript.
This manuscript was handled by: BobbieJean Sweitzer, MD, FACP.
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