Cryoanalgesia is a branch of cryotherapy (cold therapy) whose analgesic (pain-relieving) effect was known early on. As an external application of cold to relieve pain, for example, on the skeletal system in bruises and similar injuries, cryotherapy is one of the physical therapy methods and is widely used. However, cryoanalgesia, which is the topic here, refers to a minimally invasive procedure that achieves pain relief by icing a nerve plexus. Among several other applications, cryoanalgesia is primarily used to treat pain associated with so-called facet syndrome when conventional pain therapy fails. Facet syndrome is a complex of diseases affecting the facet joints of the spine, the so-called zygapophyseal joints (intervertebral joints). These are small, paired joints that exist between the articular processes (processus articularis) of adjacent vertebrae and provide mobility to the spine. The facet syndrome is characterized by a pain symptomatology that appears pseudoradicular (i.e. similar to the so-called radicular symptomatology in nerve root irritations directly at the exit from the spinal cord). Most often, facet syndrome occurs in the lumbar region of the spine (lumbar spine) due to stress. There are many causes for this symptomatology.
Indications (areas of application)
Main indication – denervation (nerve transection) of the facet joints for pain management in:
- Misused and overused facet joints.
- Reduction in height of the intervertebral space/reduction in disc height.
- Instability of the facet joints as a result of surgical interventions on the intervertebral disc.
- Neuritis (inflammation of the nerves) of the facet joint nerves.
- Osteoporosis (bone loss) or osteoporotic fractures (bone fractures) with irritation of the facet joint nerves.
- Spondyloarthritis (degenerative, arthritic changes of the facet joints).
- Synovitis (synovial inflammation) of the facet joints.
Other indications
- Intercostal pain – in rib metastases (daughter tumors in the rib area).
- Neuralgiform pain – pain that originates from a nerve itself.
- Postthoracotomy pain – pain following surgical opening of the chest.
- Triggerable pain
- Trigeminal neuralgia – pain originating directly from the trigeminal nerve (fifth cranial nerve responsible for sensitive innervation of the facial skin).
- Injury to peripheral nerves, e.g., accidental or iatrogenic (caused by a medical procedure).
Contraindications
- Inflammatory or rheumatic genesis.
- Infectious genesis
- Marcumarization that cannot be reversed
- Patients at risk who are not fit for surgery
- Tumors in the target area of treatment
Before surgery
Before the operation, a detailed medical history must be taken and the patient must be informed about possible complications. Radiographic examination of the spine, in addition to thorough clinical inspection, ensures planning of the surgery. Platelet aggregation inhibitors (prevent aggregation of blood platelets (thrombocytes); blood-thinning medications) should be discontinued approximately 5 days prior to surgery. This must be checked with the help of a blood test (coagulation parameters). To support wound healing, it is recommended that the patient stop nicotine consumption.
The procedure
Direct exposure of the peripheral nerve to cold can achieve conduction anesthesia, which means that pain impulse conduction is interrupted. This conduction block lasts for a long time, is reversible, and can be performed several times. The details of the procedure are described here using denervation of the facet joints as an example:
Cryoanalgesia can be performed during open spine surgery, or can take place percutaneously (“through the skin“) as a minimally invasive procedure. The operation takes place under sterile conditions, i.e. in a clean room (operating room). The surgical area is covered sterilely and the skin is thoroughly disinfected. The local anesthetic (local anesthetic) is applied to the incision site by means of quaddling. A probe is advanced into the target area through a stab incision.This is done under radiological control, i.e. fluoroscopy (X-ray in “real time”). The probe is double-walled so that it can be cooled internally with carbon dioxide or nitrogen. The pain-conducting nerve is then iced at approximately -60 °C. During this procedure, structures of the nerve tissue are damaged only to the extent that regeneration can occur completely in weeks or months.
After surgery
After surgery, close monitoring of the patient is necessary. In addition to surgical follow-up, the patient’s neurologic status must also be closely monitored to detect potential complications early.
Potential complications
- Irreversible damage to the nerve
- Infections
- Local frostbite – e.g. on the surface of the skin.
