Cryoneurolysis for Cutaneous Neuropathic Pain

The Effect of Ultrasound-guided Cryoneurolysis on Persistent Cutaneous Neuropathic Pain After Surgery and Trauma

Feasibility study with 25 patients investigating the effect of cryoneurolysis on persistent cutaneous neuropathic pain after surgery and trauma. All patients receive active treatment (cryoneurolysis). The study design is unblinded, non-randomized, non-controlled.

Inclusion Criteria:

• Age > 17 years
• ASA (American Society of Anesthesiologists) physical status classification system I-III
• Informed consent
• Capable of subjective evaluation of pain
• Capable of reading and understanding Danish and informed written consent
• Average pain intensity >49/100 on VAS in the primary focal pain area for a minimum of 6 months at the time of inclusion
• Relevant injury (surgery or trauma) of peripheral nerves
• Plausible cutaneous location of pain
• In the area of pain, at least one of the following (1-8): (1) Hypo/anesthesia for touch/brush (2) Hypo/anesthesia for cold (3) Hypo/anesthesia for warmth (4) Hypo/anesthesia for pinprick (5) Allodynia for touch/brush (6) Allodynia for cold (7) Allodynia for warmth (8) Hyperalgesia for pinprick
• Neuropathic pain score (Douleur Neuropathique en 4 Questions, DN-4) >3/10
• Definitive diagnosis of neuropathic pain (Finnerup et al 2016)

Exclusion Criteria:

• Inability to cooperate
• Inability to understand Danish
• Allergy to local anesthetic
• Infection in the area of cryo probe insertion
• Significant competitive chronic pain
• Progressive neurologic disease
• Increased risk at needle insertion and cold exposure (e.g. Raynaud, coagulopathies)
• Uncontrolled severe systemic disease
• Implanted electronic devices unless approved by the relevant medical specialist
• Previous cryoneurolysis with no relevant effect for the same neuropathic pain
• Previous interventional pain therapy (e.g. spinal cord stimulation) with no relevant effect for the same neuropathic pain
• Expected duration of life < 2 years
• Pregnancy
• Abuse of alcohol, narcotics or medicine
• Current psychiatric disease
• Inclusion in other clinical trials
• Ongoing patient complaint
• Body mass index < 18.5 or > 34.9 kg/m2
• Change of pain therapy within the last 28 days prior to inclusion