title: Has central sensitization become independent of nociceptive input in chronic pancreatitis patients who fail thoracoscopic splanchnicectomy?
abstract: OBJECTIVE
  Central sensitization due to visceral pancreatic nociceptive input may be important in chronic pancreatitis pain. We investigated whether bilateral thoracoscopic splanchnicectomy (BTS) to reduce nociceptive input in chronic pancreatitis patients (CPP) with poor pain control affects supraspinal and spinal sensitization.
  
  
  METHODS
  Seventeen CPP were studied preoperatively and 6 weeks after BTS. Pressure pain thresholds (PPT) were measured in clavicle and pancreatic dermatomes reflecting supraspinal and spinal central sensitization, respectively. Patients with increased PPT after BTS (hypoalgesic) were compared to those without (hyperalgesic) and PPT vs. pain numeric rating scale (NRS) changes compared.
  
  
  RESULTS
  After BTS, ten patients showed C5 PPT increases (hypoalgesic; median change 87 kPa), 7 patients had unaltered/lower PPT (hyperalgesic; -135 kPa). Preoperative pain NRS was similar between groups (4 vs. 5, P = 0.2). After BTS hypoalgesic group NRS was lower (1 vs. 6; P = 0.008) and NRS change greater (-2 vs. 0; P = 0.005). Whole group NRS and C5 PPT change correlated significantly and negatively (r = 0.53; P < 0.05), but not for pancreatic PPT.
  
  
  CONCLUSIONS
  Reduced supraspinal-but not spinal-central sensitization after BTS was associated with significantly reduced pain scores in a majority of CPP. A subgroup showed no reductions in supraspinal central sensitization after BTS, coupled to no significant pain NRS reduction. Our results suggest that a subgroup of CPP has altered pain processing that may be independent of ongoing peripheral nociceptive input, resulting in persisting pain despite BTS. If confirmed, these results indicate the importance of sensory testing for indications and management of pain treatments.
authors: Pain and Nociception Neuroscience Research Group, Department of Surgery, Radboud University Nijmegen Medical Centre, The Netherlands.
authors: Stefan A W
authors: SA
authors: Bouwense
authors: Hessel C J L
authors: HC
authors: Buscher
authors: Harry
authors: H
authors: van Goor
authors: Oliver H G
authors: OH
authors: Wilder-Smith
mesh_terms: D059333:Central Nervous System Sensitization / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods*; D050500:Pancreatitis, Chronic / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D013153:Splanchnic Nerves / Q000503:physiopathology / Q000601:surgery*; D013906:Thoracoscopy / Q000379:methods; D017211:Treatment Failure