Sacral Lateral Branches Research Articles

Incidence of neuropathic pain after cooled radiofrequency ablation of sacral lateral branch nerves.

To determine the incidence of neuropathic pain after cooled radiofrequency ablation (RFA) of the sacral lateral branches for the treatment of chronic posterior sacroiliac joint complex pain. Retrospective chart review of all patients with chronic posterior sacroiliac joint complex pain who underwent cooled RFA of the sacral lateral branches in our practice between July 2011 and February 2014. Single academic pain practice at a tertiary care medical center. Thirty-six patients with chronic posterior sacroiliac joint complex pain. All charts were reviewed to determine the procedure date, unilateral or bilateral, number of levels treated, and number of individual lesions. Side effects were assessed for their presence or absence, character, intensity, duration, and whether treatment was initiated or symptoms resolved spontaneously. Forty-eight separate procedures were performed, with a total of 193 levels and 430 lesions. Three patients had transient postprocedure neuropathic pain yielding a 0.7% (95% confidence interval [CI]± 0.4%) rate of this complication per lesion. This proportion increases to 6.2% (95% CI ± 3.5%) per procedure and to 9.4% (95% CI ± 5.2%) per patient. The incidence of postprocedural neuropathic pain after cooled RFA for posterior sacroiliac joint complex denervation is low and in a similar range to that in the lumbar spine. We consider this procedure safe to be utilized by pain medicine practitioners.

Cooled Sacroiliac Radiofrequency Denervation for the Treatment of Pain Secondary to Tumor Infiltration: A Case-Based Focused Literature Review

Background: The sacroiliac (SI) joint is a common cause of low back pain, for which radiofrequency (RF) denervation has been shown to provide long-term relief. However, controversy exists surrounding the innervation, which treatment paradigm to utilize, and how best to select patients who might benefit. Objective: To describe a patient with terminal breast cancer and tumor infiltration of the sacroiliac joint who was treated with cooled RF of the sacral lateral branches as an end-oflife palliative measure. The objectives of this review are to provide insight into the innervation of the SI joint; address controversial issues surrounding the targeted nerves in a patient with transitional anatomy; outline risk-mitigation strategies; and highlight the need for individually tailored treatment plans. Methods: Case-based focused literature review in a patient treated with cooled RF ablation of the L4-S3 primary dorsal rami and lateral branches. Results: Treatment was tailored to facilitate the rapid treatment of this terminal patient by performing the prognostic blocks and RF ablation at the same visit. Until her death 5 days post-procedure, the patient reported significant pain relief and began to ambulate and use the bathroom on her own, activities she could not do before treatment. In addition to functional improvement, she was also able to significantly reduce her opioid intake. Conclusion: This is the first report of cooled SI joint RF ablation to treat cancer pain. Our patient’s positive response to the procedure suggests the possibility that the lateral branches innervate not only the posterior ligaments, but also the bony articulation. The decision to proceed with RF ablation on the same day as a prognostic lateral branch block was based on our patient’s terminal condition, and the fact that cooled RF does not require sensory stimulation to ensure proximity to the target nerves. Because of her transitional anatomy, we elected to target L4. Key words: Cancer, denervation, innervation, radiofrequency, sacroiliac joint, transitional anatomy

Bipolar Radiofrequency Lesion Geometry: Implications for Palisade Treatment of Sacroiliac Joint Pain

Ex vivo photographic temperature mapping of bipolar radiofrequency (RF) lesions in animal tissue is performed over a wide range of electrode tip spacings, tip lengths, tip diameters, tip temperatures, and lesion times. In vivo temperature measurements collected during clinical treatment of sacroiliac joint (SIJ) pain corroborate those collected ex vivo. Generation of a "strip lesion" connecting two separated bipolar electrode tips is demonstrated ex vivo for tip spacings as large as 20 mm. A rounded rectangular bipolar lesion with midline dimensions 12 mm × 15 mm × 8 mm (L × W × D) is demonstrated using 10 mm parallel tip spacing, 10 mm tip lengths, 20 gauge cannulae, 90°C tip temperature, and 3-minute lesion time. Lesion length can be increased to 18 mm by using 15 mm tip lengths. Lesion width can be increased to 17 mm by using 12 mm tip spacing. The size of conventional bipolar lesions can exceed the size of lesions produced both by conventional monopolar RF (12 mm × 7 mm × 7 mm ellipsoidal) and by cooled monopolar RF as used in spinal pain management (10 mm × 10 mm × 10 mm spherical). SIJ pain is treated by placing 5 to 7 straight RF cannulae perpendicular to the dorsal sacrum and producing 4 to 6 overlapping bipolar RF lesions between the dorsal sacral foramina and the ipsilateral SIJ. This bipolar "palisade" (a defensive fence) creates a continuous lesion spanning the region through which multiple sacral lateral branch nerves travel along irregular, branching paths to reach the SIJ.

Cooled Radiofrequency (RF) of L5 Dorsal Ramus for RF Denervation of the Sacroiliac Joint: Technical Report

The sacroiliac joint is a common source of chronic low back pain. We recently described the use of cooled radiofrequency (RF) electrodes for performing lateral branch neurotomy to treat sacroiliac joint pain. The procedure involves lesioning the lateral branches of the posterior primary rami at S1-S3, and the L5 dorsal ramus (L5DR). While the cooled RF electrode has been adopted as a means for lesioning the lateral branches, conventional RF electrodes are used to lesion the L5DR. The objective of this technical report is to evaluate the acute safety of denervating the L5DR using cooled RF electrode. Electronic chart review was conducted on 100 consecutive RF procedures. Data collected included age, sex, years of pain, body mass index, post-procedural pain, numbness, weakness, and other complications. Of 100 procedures 82 were completed using cooled electrode for sacral lateral branches and L5DR. Of the 82 procedures completed using cooled RF to L5DR, 24 were reported to be of high difficulty and 19 with poor visualization (bowel gas). There were no major complications related to the procedure. Four patients reported increased pain: two from the conventional RF of L5DR group and two from the cooled RF group. All of the pains were transient and returned to the baseline within 6 weeks. There were two patients experiencing localized numbness over the upper medial quadrant of the buttock, both in cooled RF group. There was no reported weakness of the lower extremity. Two patients complained of increased lower back pain and two of prolonged itching. This review demonstrates the acute safety of using cooled RF for L5DR denervation with no report of significant or unusual patient complications. To establish frequency of complication associated with the treatment, a larger registry is required.

The Ability of Multi-Site, Multi-Depth Sacral Lateral Branch Blocks to Anesthetize the Sacroiliac Joint Complex

To determine the physiologic effectiveness of multi-site, multi-depth sacral lateral branch injections. Double-blind, randomized, placebo-controlled study. Outpatient pain management center. Twenty asymptomatic volunteers. The dorsal innervation to the sacroiliac joint (SIJ) is from the L5 dorsal ramus and the S1-3 lateral branches. Multi-site, multi-depth lateral branch blocks were developed to compensate for the complex regional anatomy that limited the effectiveness of single-site, single-depth lateral branch injections. Bilateral multi-site, multi-depth lateral branch green dye injections and subsequent dissection on two cadavers revealed a 91% accuracy with this technique. Session 1: 20 asymptomatic subjects had a 25-g spinal needle probe their interosseous (IO) and dorsal sacroiliac (DSI) ligaments. The inferior dorsal SIJ was entered and capsular distension with contrast medium was performed. Discomfort had to occur with each provocation maneuver and a contained arthrogram was necessary to continue in the study. Session 2: 1 week later; computer randomized, double-blind multi-site, multi-depth lateral branch blocks injections were performed. Ten subjects received active (bupivicaine 0.75%) and 10 subjects received sham (normal saline) multi-site, multi-depth lateral branch injections. Thirty minutes later, provocation testing was repeated with identical methodology used in session 1. Presence or absence of pain for ligamentous probing and SIJ capsular distension. Seventy percent of the active group had an insensate IO and DSI ligaments, and inferior dorsal SIJ vs 0-10% of the sham group. Twenty percent of the active vs 10% of the sham group did not feel repeat capsular distension. Six of seven subjects (86%) retained the ability to feel repeat capsular distension despite an insensate dorsal SIJ complex. Multi-site, multi-depth lateral branch blocks are physiologically effective at a rate of 70%. Multi-site, multi-depth lateral branch blocks do not effectively block the intra-articular portion of the SIJ. There is physiological evidence that the intra-articular portion of the SIJ is innervated from both ventral and dorsal sources. Comparative multi-site, multi-depth lateral branch blocks should be considered a potentially valuable tool to diagnose extra-articular SIJ pain and determine if lateral branch radiofrequency neurotomy may assist one with SIJ pain.

The Ability of Single Site, Single Depth Sacral Lateral Branch Blocks to Anesthetize the Sacroiliac Joint Complex

To determine the physiologic effectiveness of single site, single depth sacral lateral branch injections. Randomized, controlled, and double-blinded study. Outpatient pain management center. Fifteen asymptomatic volunteers. The dorsal sacroiliac ligament was probed and the sacroiliac joint was injected with contrast medium until capsular distension occurred. The presence or absence of pain with each maneuver was noted. Under double-blind conditions, subjects returned 1 week later for L5 dorsal ramus and S1-4 lateral branch injections; 10 subjects received 4% lidocaine (active) injections while five subjects received saline (control) injections. After 30 minutes, subjects had repeat ligamentous probing and capsular distension of the same sacroiliac joint that was previously tested. The presence or absence of pain with each maneuver was noted. In a parallel anatomic study, S1 and S2 lateral branch injections with green dye were performed on two nonembalmed cadavers. Dissection was undertaken to quantify the degree of staining of these target lateral branch nerves. Presence or absence of pain for ligamentous probing and sacroiliac joint capsular distension. Forty percent had no discomfort upon repeat ligamentous probing after active lateral branch injections while 100% retained pain upon repeat ligamentous probing with control lateral branch injections. Forty percent of the active group and 20% of the control group did not feel repeat capsular distension of the sacroiliac joint after the lateral branch injections. In the anatomic study, 11 lateral branch nerves were isolated while staining occurred in only four cases or 36%. Anatomic limitations exist with single site, single depth sacral lateral branch injections rendering them physiologically ineffective on a consistent basis.

Cooled Radiofrequency System for the Treatment of Chronic Pain from Sacroiliitis: The First Case‐Series

Sacroiliitis and sacroiliac (SI) joint dysfunction are frequent causes of the chronic lower back pain. Therapeutic solutions include intra-atricular injections with short-term pain relief and surgical fusion, which appears ineffective. Radiofrequency (RF) of the joint capsule or lateral branches has been previously reported with variable successes. Cooling tissue adjacent to the electrode (cooled RF) increases the radius of lesion. We present here the first retrospective data on pain relief and changes in function after such RF denervation. We reviewed electronic records of 27 patients with chronic low back pain (median 5 years) who underwent cooled RF of S1, S2, and S3 lateral branches and of dorsal ramus (DR) L5 following two diagnostic SI joint blocks (>50% of pain relief). Patient sample consisted of 20 women and 7 men, 38 to 92 years old. Pain disability index (PDI), visual analog scale (VAS) pain scores, global patient satisfaction (GPE) and opioid use before and 3-4 months after the procedure were analyzed. One patient had an incomplete chart. Observed were improvements in function (PDI) from 32.7 +/- 9.9 to 20.3 +/- 12.1 (P < 0.001) and VAS pain scores 7.1 +/- 1.6 to 4.2 +/- 2.5 (P < 0.001) at 3-4 months after the procedure. Opioid use decreased from median 30 to 20 mg morphine equivalent. Eighteen patients rated their improvement in pain scores using GPE as improved or much improved, while eight claimed minimal or no improvement. The majority of patients with chronic SI joint pain experienced a clinically relevant degree of pain relief and improved function following cooled RF of sacral lateral branches and DR of L5 at 3-4 months follow-up.