Periradicular Therapy

Periradicular therapy (PRT) is a CT-guided procedure (CT-PRT; CT: computed tomography) developed in the 1980s. It is a common percutaneous (applied through the skin) form of therapy in neurosurgery, used primarily as a pain therapy for radicular symptoms (pain originating from the nerve roots in the spine). The basis of the procedure is the application of a local anesthetic or corticosteroids directly to the locally inflamed, compressed or stretched nerve root. Periradicular therapy is a low-risk, minimally invasive treatment. The procedure is preferable to surgery in all cases, unless severe paralysis is present. This procedure has both therapeutic and diagnostic value. If the origin of specific complaints is unclear or if the imaging does not match the symptomatology, the comparison during the puncture can provide information: If the pain – triggered by the contact of the cannula with the nerve root – matches the pattern of complaints, the application of medication is indicated. If this is not the case, further search for another cause is needed.

Indications (areas of application)

  • Compression-induced radicular pain
  • Acute or chronic radicular symptoms due to disc protrusion or prolapse (bulging of the disc or herniated disc)
  • Radicular lumbar syndromes
  • Stenosis of the neuroforamina – narrowing of the exit holes of the nerves from the spine.
  • Unclear radicular pain – it is not apparent from which nerve root the pain originates
  • Postoperative (after surgery) radicular pain.

Contraindications

  • Higher degree paralysis (these should be treated immediately by surgery).
  • Acute infections
  • Thrombocytopenias (lack of platelets) and blood clotting disorders.
  • Allergies to the drugs or contrast media to be applied.
  • Known cerebrospinal fluid leak – the spinal cord and brain are located in a closed space filled with cerebrospinal fluid, a clear nourishing fluid. If this space has a hole, there is a risk of administration of narcotics into the central nervous system with significant side effects).

Before treatment

  • To confirm the indication, a pathomorphologic correlate should be available in a recent cross-sectional imaging (CT, better MRI) before the procedure.
  • Inform the patient at least 24 hours before therapy.
  • Current cross-sectional examinations of the therapy region.
  • Current blood coagulation (Quick > 90%), blood count, C-react. Protein (CRP) in erosive osteochondrosis (degenerative disease of bone and cartilage).

The following quality standards should be present:

  • The physician performing the intervention must be board certified in orthopedics or neurosurgery and have sufficient surgical experience in the spine.
  • The intervention should be performed exclusively in a clinic with an operating department and the possibility of inpatient treatment.
  • The intervention should be performed under CT or MRI guidance.
  • An image document and written report should be obtained for each treatment.
  • If more than 3 PRT’s per segment have been performed, this must be decidedly justified in writing, e.g. in the case of spinal or recess stenosis.

The procedure

Before the procedure, the coagulation status (blood clotting) and any allergies to contrast media or the drugs must be checked. During the procedure, the patient is in the prone position for lumbar (involving the lumbar vertebrae) and thoracic (involving the thoracic vertebrae) PRT and in the lateral position for cervical (involving the cervical vertebrae) PRT. The procedure is performed under CT control, which means that the treating physician can follow each of his or her steps pictorially. First, a CT is taken of the target root to determine the exact location, angle and depth of the puncture. The region is marked and then thoroughly disinfected. The puncture needle is now placed and advanced toward the nerve root; local anesthesia (local anesthetic) may be required. The position of the injection needle is then checked with possible position correction via CT.If the needle is in the correct position, the patient will describe a pain sensation that corresponds to the usual manner of his complaints. This is followed by the aspiration test, which is performed to exclude a spinal tap or intrathecal application in the further course. The aspiration test is positive if a small amount of test fluid is aspirated from the cannula. This would mean that the spinal cord has been punctured. There is a risk of injury and of administration of the anesthetic into the central nervous system, this can have severe side effects. If aspiration is negative, contrast is injected to follow the distribution of the fluid on the CT. If this is correct, the drug can be applied slowly. After removal of the surgical instruments, the wound is disinfected and dressed with a plaster bandage. In the case of complaints caused by complex changes in the spine and affecting several nerve roots, two segments are treated with a time delay. Treatment of additional nerve roots should be done in a separate session.

After treatment

  • Immediately after treatment, paresthesias (numbness) or feelings of weakness and even temporary paralysis may occur in the leg. These symptoms usually resolve on their own after 2 to 5 hours.
  • On the day of treatment, the patient should take it easy, avoid sporting activities and lifting heavy loads. Furthermore, the patient should not drive himself (but bring a driver).

Possible complications

  • Contrast agent intolerance
  • Drug side effects (essentially due to glucocorticoids):
    • Facial flushing
    • Hyperhidrosis (increased sweating)
    • Glucose level increase
    • Blood pressure rise
    • Stomach discomfort
    • Calf cramps
  • Bleeding
  • Infection
  • Nerve injury
  • Paralysis
    • Temporary paralysis [common].
    • Transient paralysis associated with accidental application to the dural sac
    • Permanent paralysis up to paraplegia [extremely rare].