Techniques in regional anesthesia & pain management最新文献

Thoracic spine pain is a relatively common condition. Pain in this region may be attributable to dysfunction of the thoracic facet joint. The true prevalence of thoracic facet pain remains somewhat elusive. Although challenging to diagnose at times, this joint is amenable to several therapeutic options. Radiofrequency neurotomy and thoracic medial branch blocks are normally used to treat facetogenic pain originating in the thoracic spine. Although demonstrating promise, larger, robustly designed trials are needed to further elucidate the appropriate treatment of this disorder.

Partial neurotomy of painful large joints may be accomplished by radiofrequency (RF) lesioning of the articular branch innervation of these joints. Successful RF lesions of the knee and the hip are clinically useful procedures whose success depends upon the knowledge of articular branch neuro anatomy and the practitioner’s optimized choice of RF probe for the procedure. Although clearly indicated for patients who may not be medically suitable for arthroplasty, the procedures may be invaluable in preserving functional mobility and providing non-opiate pain relief for many patients with articular pain including those with postarthroplasty pain. Techniques for diagnostic nerve blocks and varied approaches for anatomically optimized RF lesioning of the innervation of the hip and knee are provided.

Chronic abdominal pain is a complex physical and psychological problem that requires comprehensive treatment options tailored to the needs of patients. Splanchnic nerve blocks and radiofrequency denervation of greater and lesser splanchnic nerves may provide prolonged treatment effect that still needs to be studied in a randomized prospective fashion. Here we describe improved fluoroscopy-guided technique for the radiofrequency ablation of splanchnic nerves, details on approach, technique, and potential complications.

Radiofrequency ablation (RFA) is a safe and effective pain therapy with efficacy principally reliant upon induced thermal damage of neural sensory afferents. Most peripheral RFA involves induced axonal damage but cell bodies may be involved indirectly. Radiofrequency electrodes (RFE) are not simple high-temperature probes and better insight regarding RFE function from an electrical engineering viewpoint may improve clinical outcomes by reducing the risk of poor or inadequate heating of the target nerves. RFE heating is highly influenced by the configuration and properties of the perielectrode tissues with the shape and size of RFE-produced protein coagulum seen in vitro with homogeneous media such as egg white, liver, or chicken skeletal muscle undoubtedly significantly different than the biological lesions occurring during in vivo clinical use. Understanding RFA requires consideration of the nature of the specific perielectrode tissues. A theoretical basis for optimized RFE function for lumbar medial branch (MB) neurotomy is presented with introduction of the concepts of clinically useful heating and useless heating. Conventional RFE is limited in the amount of current/heating produced for a given active electrode surface area before producing a radiofrequency generator fault and an inverse relationship exists between clinically useful heating and useless heating. Technical details of RFE function are discussed that may differ from presently accepted technique. Tined RFE, similar in function to conventional RFE, may offer a small advantage if properly used, and possibly a disadvantage if used incorrectly. Directly conducted heat is often neglected in considering RFA, but should be considered, especially with water-cooled RFE (WCRFE). Theory and empirical results suggest that WCRFE might become a preferred tool for much, but not all, RFA, but adoption has been limited by electrode cost and reimbursement policies. Conventional and tined RFE may produce poor outcomes if placed improperly, but complications due to overheating are quite rare. Conversely, WCRFE introduces far more heat into perielectrode tissues and reduces the likelihood of a poor clinical outcome, but avoidance of complications due to overheating of adjacent tissues requires a thoughtful understanding of the spatial and thermal characteristics of the WCRFE.

Neck pain is a common diagnostic entity, with a lifetime prevalence of between 65% and 80%. Appreciation of the role of the cervical facet joints in the etiology of cervical spine pain is paramount to providing sustained pain relief for individuals suffering from degenerative and posttraumatic neck pain. Studies have demonstrated that approximately 60% of patients who sustain whiplash-type rear-end motor vehicle collisions would have pain that results from the facet joints alone, or in conjunction with the cervical intervertebral disks. An appreciation of the anatomical foundation for the development of these painful conditions includes knowledge of the dual, overlapping innervation of each cervical facet joint with contributions from levels at, and above the joint. Medial branch nerves invest the joints; are held closely adherent to the articular pillars by tendons of the semispinalis capitis muscles; and can be treated using local anesthetic nerve blocks followed by radiofrequency (RF) procedures for prolonged benefit. Nerves in facet joints contain modified nociceptors, including silent nociceptors, low-threshold mechanoreceptors, and mechanically sensitive nociceptors. Nerves within facet joints are both free and encapsulated and contain Substance P and calcitonin gene–related peptide. Treatment approaches must address these diverse anatomical and physiological phenomena to provide the highest level of interventional therapy. Large, well-conducted studies have demonstrated the efficacy and safety of providing short-term symptomatic pain relief using cervical facet medial branch nerve blocks. Continuous-energy thermal lesioning RF ablation techniques of the cervical medial branches may produce pain relief that persists for up to 12 months in two-thirds of patients so treated. A systematic review of well-conducted studies recently published confirmed that the evidence in favor of using RF ablation is level II for the long-term effectiveness of RF neurotomy and facet joint nerve blocks in managing cervical facet joint pain. Imaging for performing these procedures is mandatory to assure success and to minimize adverse events from occurring. Fluoroscopy is a standard imaging technique, but ultrasound and even computed tomography scan guidance have been documented to be satisfactory in properly trained interventionalists. The cervical facet joints with their medial branches represent a reliable target for directing interventional therapies aimed at addressing nociceptive type pain, albeit with a neurogenic component. Future studies would reflect our evolving appreciation of these intricate anatomical networks of innervation and their role in the etiology of chronic headache and neck pain.

The objective of this article is to recommend an approach to radiofrequency ablation (RFA) of the sacral lateral branches that is safe, effective, and simple to perform. To do so, one must identify the proper patient, perform a diagnostic block to confirm the sacroiliac joint as the pain generator, and then, after 2 successful blocks, move to RFA of the sacral lateral branches as the next step in treatment. The choice of an RFA technique is controversial. Here, an argument is made for moving to bipolar RFA of the lateral branches of S1-S3. If pain is refractory, then cooled RFA may be an appropriate next step in care.