A 71 year old male with medical history of myocardial infarction s/p aortocoronary bypass surgery (CABG x4) in 2018, had developed shingles prior to CABG. Patient was evaluated at physiatry clinics for severe, diffuse, constant, burning right hemithorax pain, of one year duration since his emergent surgery.
Patient’s pain interfered with sleep, was exacerbated by soft tactile stimuli including friction from clothes, and mildly alleviated upon squeezing a pillow against his chest as sensory trick. Examination showed allodynia, hyperpathia and dysesthesias along right T7-T10 dermatomal distribution. Clinical impression was a possible intercostal neuralgia versus post-thoracotomy pain syndrome, refractory to mainstay pharmacotherapy and intercostal nerve block for T9-T10 levels; hence, IncobotulinumtoxinA infiltration trial was offered.
Initially IncobotulinumtoxinA 150 units was infiltrated, by placing a subtotal 100 units subcutaneously among forty 2.5 unit flares at 1.5cm of each other, distributed along affected right hemithorax dermatomes T7-T10 from mid-axillary line to abdominal and peri-scar regions. The remaining 50 units were administered at corresponding right T7-T10 dorsal skin and paraspinals using electromyographic guidance.
Patient reported pain relief in just 3 days. During the12 week’s reassessment, patient presented mild and tolerable residuals of pain only affecting a narrowed anatomical region over right T7-T8 abdominal region. Decision was made to omit infiltration on right T9-T10 abdomen for the second IncobotulinumtoxinA trial.
Our experience showed that a once chronic, intractable hemithorax pain with neuropathic qualities was responsive to a single IncobotulinumtoxinA infiltration, achieving greater than 50% pain relief. We hypothesize this patient’s exceptional treatment response was mediated by our injection technique - learned from previous clinical experience, which targets the whole sclerotome segment. We hypothesize this injection technique, when performed with neurotoxin, advances the onset of pain relief and facilitates a longstanding sustained therapeutic response, possibly mediating modulatory effects on chronic pain.
Keryl Motta-Valencia– PMR Attending physician, VA Caribbean Healthcare System
Rocio Delgado-Diaz– PGY3, PM&R Residency Program, Veterans Health Administration, San Juan, Puerto Rico
Ady Correa-Mendoza– PGY 3 Resident, VA Caribbean Healthcare System, San Juan, PR
Eduardo Maldonado-Colón– Resident Physician, VA Caribbean Healthcare System
Anabel Jimenez-Figueroa– PMR Attending physician, VA Caribbean Healthcare System
Joanne Gonzalez- Feliciano– PMR Attending physician, VA Caribbean Healthcare System