AREAS OF RESEARCH ACTIVITY

1) Perioperative nociception and pain

Our research emphasis in this area is on diagnosing and quantifying perioperative nociceptive inputs due to surgery and their consequences in the acute postoperative period (up to 1 week postoperatively). The insight derived from this research offers a basis for more rational mechanism-based anaesthetic and analgesic management of the surgical patient, and forms the basis for the prevention of subsequent pain chronification (cf. below). more...

Main ongoing projects:

• Documenting pain and analgesic management on the PACU as the basis of a quality management system
• Hyperalgesia on the PACU: Incidence, factors and modulation

(PhD Tobias Schreyer)

 

2) Pain chronification

Over the last five years, it has become obvious that surgery is a major source of chronic pain, with some types of surgery (e.g. amputation, thoracotomy) being associated with chronic pain incidences of over 50% one year after surgery. In view of the poor prognosis and therapeutic response of such chronic pain, the prevention of chronic pain after surgery is a major societal challenge. A further reason for the attractiveness of researching the mechanisms of chronic pain after surgery is that we can follow its entire course from before the initiating trauma until the actual development of chronic pain. This knowledge may also help provide insight into the chronification of other types of pain. more...

Main ongoing projects:

• Documenting the incidence of chronic pain after surgery: retrospective studies of various surgical interventions
• Neuroplasticity and pain chronification after surgical interventions: prospective studies of mastectomy, sternotomy and thoracotomy

(PhD Monique Steegers)

• Preventing Pain Chronification after Surgery: Using Quantitative Sensory Testing to Predict Patients at Risk and to Understand Mechanisms as a Basis for Effective Preventive Treatment Strategies (financed by ZONMW)
• Relative Contributions of Humoral and Nerve Nociceptive Inputs to Postoperative Central Sensitisation and Pain: Interaction of Extended Perioperative COX-2 Inhibition and Local Anaesthetic Blockade for Breast Malignancy Surgery (financed by an independent investigator research grant from Pfizer)

 

3) Chronic pain syndromes

Chronic pain is a major societal problem, both from the medical and from the employment point of view. In the Netherlands, for example, population prevalences of 40% are reported for chronic low back pain. Chronic pain, once established, is difficult to treat and has a poor prognosis, with 32% of chronic low back pain patients, for example, being unable to work at all. Thus the prevention of chronic pain should be a major goal, as already discussed above.

A major reason why established chronic pain is so difficult to treat is the lacking understanding of underlying mechanisms. This leads to symptom based diagnostic categorization, with the probable consequence that many disorders based upon diverse mechanisms are lumped together in a single diagnostic category. This, together with an approach focused almost exclusively on (pain) symptom control, is the underlying cause of the very limited therapeutic success presently achieved even by the best centres active in pain medicine. Thus the main focus of our research on chronic pain is the development of diagnostic techniques providing insights into mechanisms, particularly those involving alterations of pain and sensory processing (neuroplasticity). These techniques provide us with the basis for our research into optimization of pharmacological (e.g. drugs) and non-pharmacological (e.g. electrical stimulation, neuromodulation) therapeutic interventions for chronic pain. The diagnostic techniques at presently being developed, validated and applied to various chronic pain syndromes include batteries of a variety of types of active and passive quantitative testing to monitor neuroplasticity, neuroimaging techniques (e.g. fMRI; in collaboration with the F.C. Donders Centre), neurophysiological methods (e.g. single run evoked potentials, ERP; in collaboration with NICI) and cognitive testing batteries (in collaboration with NICI).

Our research on chronic pain has a particular emphasis on chronic pain due to surgery, low back pain, complex regional pain syndrome (CRPS) and visceral pain syndromes such as chronic pancreatitis. We are at present studying and following large collectives of these patients to understand underlying mechanisms and improve diagnostics. To date, we have been able to demonstrate the extensive contributions of central sensitization (hyperalgesia, both nociceptive input dependent and autonomous) in several of the pain syndromes listed above – and the negative contribution of currently accepted therapies (e.g. chronic opioid treatment) to this phenomenon. These results are thus supportive of the concept that chronic pain is a neurological disease group in its own right, with its own unique pattern of mechanisms (e.g. central sensitization, neurodegeneration, alterations of cognitive function) and thus with its own specific diagnostic and therapeutic requirements.

Main ongoing projects:

• Neuroplasticity and the chronic pain of pancreatitis
• Effects of therapeutic interventions on neuroplasticity and pain in chronic pancreatitist

(PhD Hessel Buscher)

• Visceral and somatic QST colonic surgery: an observational study
• Complex visceral pain syndromes: effects on visceral and somatic QST

(PhD Willem Brinkert)

• Are segmental nerve blocks useful in the identification and treatment of spinal segmental pain in patients with chronic radiating low back pain without overt focal neurological deficits?

(PhD André Wolff)

• Pain mechanisms in patients with CRPS type I: An fMRI study
• Pain mechanisms in patients with chronic low back pain: An fMRI study

(PhD Noortje Vis)