Are the nerves supplying the anterior sacroiliac joint nociceptive?

BACKGROUND: Sacroiliac joint (SIJ) pain is often difficult to diagnose. Moreover, while its anatomical characteristics have been well studied, its innervation and the contributions of particular nerves remain controversial, especially in relation to posterior joint innervation. To our knowledge, previous studies have not investigated the presence of nociceptive fibres in the nerves innervating the anterior SIJ. MATERIALS AND METHODS: Eight adult cadaveric sides underwent dissection of the anterior SIJ. Adjacent anterior rami were examined for branches to the anterior SIJ. Any branches contributing to the anterior SIJ were measured and then resected. These samples were fixed in formalin and substance P was identified immunohistologically. RESULTS: On all sides, 1-2 small branches (mean diameter of 0.33 mm) arose from the posterior aspect of the L4 anterior ramus (12.5%), the L5 anterior ramus (62.5%), or simultaneously from both the L4 and L5 anterior rami (25%). These branches had a mean length of 13.5 mm. All histological samples contained nerve tissue. All samples of nerve fibres traveling to the anterior SIJ were positive for diffuse substance P reactivity. There were no histological differences between sides or sex. Each of the branches identified as travelling to the SIJ exhibited similar positivity for substance P. CONCLUSIONS: This cadaveric study demonstrates that the anterior SIJ nerve fibres carry pain fibres. This new knowledge has application to patients with SIJ syndrome and to its various treatments including interventional approaches to SIJ pain.

Evaluation of an Ultrasound-Assisted Longitudinal Axis Lateral Crest Approach to Radiofrequency Ablation of the Sacroiliac Joint.

OBJECTIVE: The aim of the study was to evaluate the effectiveness and procedural characteristics of a novel, ultrasound/fluoroscopically guided technique (longitudinal axis sacroiliac joint radiofrequency ablation) for sacroiliac joint denervation. DESIGN: A single-arm cohort with historical cohort comparison was used in this study. METHODS: Thirty-seven participants underwent longitudinal axis sacroiliac joint radiofrequency ablation after 50% or more pain reduction after diagnostic dual-block criterion. Outcomes were the proportion of participants with 50% or more pain reduction and mean Pain Disability Quality of Life Questionnaire change. Subanalysis included longitudinal axis sacroiliac joint radiofrequency ablation procedural and fluoroscopy times compared with participants previously treated with palisade radiofrequency ablation technique. RESULTS: Primary outcome worst case analysis demonstrated a responder rate of 64.9% (95% confidence interval = 48.8%-78.2%) and 59.5% (95% confidence interval = 43.5%-73.7%) at 3 and 6 mos. There was significant decrease in mean Pain Disability Quality of Life Questionnaire at 3 (45.6 ± 9.5 to 21.4 ± 16.0, P < 0.001) and 6 mos (45.6 ± 9.5 to 23.0 ± 16.5, P < 0.001). Longitudinal axis sacroiliac joint radiofrequency ablation required more procedure time than the palisade technique (38.2 ± 7.9 vs. 32.1 ± 6.9 mins, P = 0.031) but less fluoroscopy time (35.0 ± 11.8 vs. 57.6 ± 16.8 secs, P < 0.001). CONCLUSIONS: Longitudinal axis sacroiliac joint radiofrequency ablation resulted in improvement in pain, disability, and quality of life at 3 and 6 mos. Compared with the palisade technique, longitudinal axis sacroiliac joint radiofrequency ablation required greater procedure time but less fluoroscopy time.

Preliminary Results of Endoscopic Radiofrequency Treatment of the Sacroiliac Joint Syndrome.

BACKGROUND AND STUDY: The sacroiliac joint (SIJ) may be the primary source of pain in 15 to 25% of patients with axial low back pain. Furthermore, 75% of patients who have had fusion surgery develop SIJ pain within 10 years. Treatment options include SIJ blocks, radiofrequency (RF) denervation, and fusion. The RF techniques range from ablation of the nerves supplying the joint, creating lesions to the joint itself, or a combination of both techniques. However, different clinical studies could only identify a limited or, in some cases, no effect in decreasing of pain intensity and duration of the effect. METHODS: In this retrospective study, we selected 23 patients with SIJ pain, with a duration of more than 12 months and a 50% pain reduction on the Numeric Rating Scale (NRS) after diagnostic block. All patients received endoscopic ablation of the medial branch L5/S1 and the lateral branches, exiting the sacral foramina on S1/S2 and S2/S3 on both sides while using only one incision on each side. Telephone interviews were conducted with all patients. The outcome was determined with Odom's criteria, percent reduction NRS, subjective assessment of the patient, and duration of the effect. RESULTS: According to Odom's criteria, 79% of the patients showed acceptable to excellent results and confirmed that denervation helped them to manage their daily lives better. The average pain reduction in the responder group was 57% with an average duration of 13.4 months. CONCLUSION: In this retrospective study, we could demonstrate the practicability and effectiveness of endoscopic SIJ denervation in the treatment of SIJ pain using only one incision for three levels on each side. Further studies should investigate if this procedure is more effective than percutaneous RF.

High-frequency thermal coagulation to treat middle cluneal nerve entrapment neuropathy.

OBJECTIVE: Middle cluneal nerve entrapment (MCN-E) around the sacroiliac joint can elicit low back pain (LBP). Pain control can be obtained with anesthetic nerve blocks; however, when their effectiveness is transient, surgical release may be necessary. We investigated the efficacy of radiofrequency thermocoagulation (RFTC) in patients with MCN-E. METHODS: Between December 2018 and August 2019, 11 consecutive patients (4 men, 7 women; mean age 76.4 years) with intractable medial buttock pain due to MCN-E underwent MCN RFTC. The mean symptom duration was 49.5 months; pre-RFTC local MCN blocks provided pain relief for a mean of 7.7 days. The severity of pain in the medial buttock due to MCN-E was recorded before and 2, 6, 12, and 24 weeks after RFTC on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). RESULTS: All patients reported pain alleviation; there were no complications. While there was a significant difference in the pre- and post-RFTC treatment NRS (p < 0.05), the RDQ scores were significantly lower only after 12 weeks. The duration of pain relief was significantly prolonged by RFTC (p < 0.05). Two patients suffered pain relapse 10 weeks post-RFTC; pain alleviation was obtained by re-RFTC performed 2 weeks after pain recurrence. Two other patients relapsed 20 and 21 weeks post-RFTC; their symptoms also disappeared by MCN block administered 24 weeks after they had undergone RFTC. CONCLUSION: RFTC may safely control intractable LBP due to MCN-E.

Cost-Effectiveness of Radiofrequency Denervation for Patients With Chronic Low Back Pain: The MINT Randomized Clinical Trials.

OBJECTIVES: To evaluate the cost-effectiveness of radiofrequency denervation when added to a standardized exercise program for patients with chronic low back pain. METHODS: An economic evaluation was conducted alongside 3 pragmatic multicenter, nonblinded randomized clinical trials (RCTs) in The Netherlands with a follow up of 52 weeks. Eligible participants were included between January 1, 2013, and October 24, 2014, and had chronic low back pain; a positive diagnostic block at the facet joints (n = 251), sacroiliac (SI) joints (n = 228), or a combination of facet joints, SI joints, and intervertebral discs (n = 202); and were unresponsive to initial conservative care. Quality-adjusted life-years (QALYs) and societal costs were measured using self-reported questionnaires. Missing data were imputed using multiple imputation. Bootstrapping was used to estimate statistical uncertainty. RESULTS: After 52 weeks, no difference in costs between groups was found in the facet joint or combination RCT. The total costs were significantly higher for the intervention group in the SI joint RCT. The maximum probability of radiofrequency denervation being cost-effective when added to a standardized exercise program ranged from 0.10 in the facet joint RCT to 0.17 in the SI joint RCT irrespective of the ceiling ratio, and 0.65 at a ceiling ratio of €30 000 per QALY in the combination RCT. CONCLUSIONS: Although equivocal among patients with symptoms in a combination of the facet joints, SI joints, and intervertebral discs, evidence suggests that radiofrequency denervation combined with a standardized exercise program cannot be considered cost-effective from a societal perspective for patients with chronic low back pain originating from either facet or SI joints in a Dutch healthcare setting.

Sacroiliac Joint Ablation Using MR-HIFU.

The sacroiliac joint is the culprit in 15-30% of patients with chronic lumbar back pain. Ablation of the posterior sensory nerves supplying the joint is an established treatment option before arthrodesis. We report the successful application of MR-HIFU in a patient with therapy-refractory pain using the Sonalleve MR-HIFU system. The outpatient procedure was performed under spinal anaesthesia and analgosedation. The ramus dorsalis of L5 as well as the lateral branches of the ramus dorsalis S1-S3 was targeted, and tissue peak temperature per sonication was controlled using MR-thermometry. There were no post-interventional complications. Clinical improvement began 4 days post-intervention with complete resolution of the pain after 1 month.

Innervation of the Anterior Sacroiliac Joint.

OBJECTIVE: Sacroiliac joint pain can be disabling and recalcitrant to medical therapy. The innervation of this joint is poorly understood, especially its anterior aspect. Therefore, the present cadaveric study was performed to better elucidate this anatomy. METHODS: Twenty-four cadaveric sides underwent dissection of the anterior sacroiliac joint, with special attention given to any branches from regional nerves to this joint. RESULTS: No femoral, obturator, or lumbosacral trunk branches destined to the anterior sacroiliac joint were identified in the 24 sides. In 20 sides, one or two small branches (less than 0.5 mm in diameter) were found to arise from the L4 ventral ramus (10%), the L5 ventral ramus (80%), or simultaneously from both the L4 and L5 ventral rami (10%). The length of the branches ranged from 5 to 31 mm (mean, 14 mm). All these branches arose from the posterior part of the nerves and traveled to the anterior surface of the sacroiliac joint. No statistical significance was found between sides or sexes. CONCLUSIONS: An improved knowledge of the innervation of the anterior sacroiliac joint might decrease suffering in patients with chronic sacroiliac joint pain.

Sacro-Iliac Joint Sensory Block and Radiofrequency Ablation: Assessment of Bony Landmarks Relevant for Image-Guided Procedures.

Image-guided sensory block and radiofrequency ablation of the nerves innervating the sacro-iliac joint require readily identifiable bony landmarks for accurate needle/electrode placement. Understanding the relative locations of the transverse sacral tubercles along the lateral sacral crest is important for ultrasound guidance, as they demarcate the position of the posterior sacral network (S1-S3 ± L5/S4) innervating the posterior sacro-iliac joint. No studies were found that investigated the spatial relationships of these bony landmarks. The purpose of this study was to visualize and quantify the interrelationships of the transverse sacral tubercles and posterior sacral foramina to inform image-guided block and radiofrequency ablation of the sacro-iliac joint. The posterior and lateral surfaces of 30 dry sacra (15 M/15 F) were digitized and modeled in 3D and the distances between bony landmarks quantified. The relationships of bony landmarks (S1-S4) were not uniform. The mean intertubercular and interforaminal distances decreased from S1 to S4, whereas the distance from the lateral margin of the posterior sacral foramina to the transverse sacral tubercles increased from S1 to S3. The mean intertubercular distance from S1 to S3 was significantly (p < 0.05) larger in males. The interrelationships of the sacral bony landmarks should be taken into consideration when estimating the site and length of an image-guided strip lesion targeting the posterior sacral network.

Ultrasound indications for chronic pain management: an update on the most recent evidence.

PURPOSE OF REVIEW: The ability of ultrasound to provide detailed anatomic visualization while avoiding radiation exposure continues to make it an appealing tool for many practitioners of chronic pain management. This review will present the most recent evidence regarding the use of ultrasound-guidance for the performance of interventional procedures in the treatment of chronic pain. RECENT FINDINGS: For a variety of different procedures, studies continue to compare ultrasound-guided techniques to commonly used fluoroscopic or landmark-based techniques. Small, randomized controlled trials are beginning to demonstrate that ultrasound-guided approaches to interventional pain procedures can be as well tolerated and effective as the traditionally used techniques, while providing some potential advantages in terms of decreased radiation exposure, avoidance of vascular structures, and in some cases, improved efficiency and decreased rates of adverse effects. SUMMARY: Despite continued interest in ultrasound-guided techniques for chronic pain management procedures, the evidence is still limited mainly to small, randomized trials and case series. For some procedures, such as stellate ganglion block and peripheral joint injections, recent evidence appears to be tilting in favor of ultrasound-guidance as the preferred technique, though fluoroscopy continues to be a much more reliable method for detection of intravascular uptake of injectate.

[The crux of the sacroiliac joint]. / De crux van het sacro-iliacale gewricht.

Pain from the sacroiliac (SI) joint is, along with osteoarthritis of the facet joints, one of the main sources of mechanical low back pain. Here we discuss the negative results of two recent randomized controlled trials in the Netherlands on the use of radiofrequency (RF) denervation to treat low back pain arising from the SI joint. Possible causes of treatment failure are discussed. The authors also discuss the use of an intra-articular injection of the combination of a local anaesthetic and a glucocorticoid as an alternative to RF denervation.

Clinical Outcome Following Radiofrequency Denervation for Refractory Sacroiliac Joint Dysfunction Using the Simplicity III Probe: A 12-Month Retrospective Evaluation.

BACKGROUND: Sacroiliac joint syndrome (SIJ) is diagnosed in 10% to 25% of cases of lower back pain. The response to traditional radiofrequency (RF) denervation of the SIJ has being inconsistent. The Simplicity III RF probe (Neruotherm. Inc.) offers a novel treatment option. OBJECTIVE: To evaluate the long-term clinical outcome (12 months) refractory SIJ syndrome in terms of pain intensity and functional improvement. A 50% reduction in intensity pain intensity (VAS) at 12 months was deemed clinically significant. STUDY DESIGN: A 12-month retrospective observational evaluation all of adults treated with RF for refractory SIJ. SETTING: Chronic pain management center. METHODS: The medical records of all adults treated with this technique was retrospectively reviewed. The primary outcome was pain intensity scores (VAS) over a 12 months period; Secondary outcomes included Roland-Morris Functional scores (RMF), Brief Pain Inventory (BPI), general health assessment (Sf12), and patient satisfaction scores (GPI), which were recorded pre and post denervation. REULTS: Pain Intensity improved by 4.7 points compared to pre-treatment representing a 61% reduction in pain at 12 months (n=11, P < 0.001). Significant improvements in (a) RMF (P < 0.01, W2 = 0.63 (large effect size); (b) BPI (P < 0.001, W2 = 0.72 (strong effect size); and (c) Sf12 (P < 0.01) were noted. Overall patients were satisfied with the outcome (GPI = 77.7%). LIMITATIONS: The retrospective in nature of the study and the small sample size are limitations. As it was our policy to monitor the progress of the individuals since the introduction of this technique a reliable method of recording the baseline and outcome variables at each point of contact was in place. Access to a complete set of variables in all individuals over a 12-month period was therefore possible, which we feel contributes to the quality of the dataset. CONCLUSION: By creating a consistent radiofrequency lesion between the sacral foramen and the SIJ will reliably capture the innervation to the SIJ with significant long-term clinical improvement. This technique should be considered earlier in the treatment algorithm of individuals suffering from SIJ symptoms.

Comprehensive anatomical and immunohistochemical review of the innervation of the human spine and joints with application to an improved understanding of back pain.

BACKGROUND: Pain of spinal origin contributes significantly to cervical, thoracic, and lower back pain presentations. Such pain originates in the nerve fibers supplying the joints or the surrounding ligaments and intervertebral discs. Although there has been little detailed discussion of spinal bony innervation patterns in the literature, the clinical implications of these patterns are anatomically and medically significant. METHODS: The present review provides a detailed analysis of the innervation of the spine, identifying the unique features of each part via online search engines. CONCLUSIONS: The clinical implications of these various studies lie in the importance of the innervation patterns for the mechanism of spinal pain. Immunohistochemical studies have provided further evidence regarding the nature of the innervation of the spine.

Long-term follow-up in sacroiliac joint pain patients treated with radiofrequency ablative therapy.

Sacroiliac joint (SIJ) pain is responsible for up to 40% of all cases of lumbar back pain. Objective Report the long-term efficacy of radiofrequency denervation for sacroiliac joint pain at six, twelve and eighteen months.Method Third-two adults' patients with sacroiliac join pain diagnosis were included for a prospective study. Primary outcome measure was pain intensity on the Numeric Rating Scale (NRS). Secondary outcome measure was Patient Global Impression of Change Scale (PGIC).Results Short-term pain relief was observed, with the mean NRS pain score decreasing from 7.7 ± 1.8 at baseline to 2.8 ± 1.2 at one month and to 3.1 ± 1.9 at six months post-procedure (p < 0.001). Long-term pain relief was sustained at twelve and eighteen months post-procedure, with NRS pain remaining at 3.4 ± 2.1 and 4.0 ± 2.7, respectively.Conclusion Radiofrequency denervation of the SIJ can significantly reduce pain in selected patients with sacroiliac syndrome.

Long-term follow-up in sacroiliac joint pain patients treated with radiofrequency ablative therapy / Seguimento longo em pacientes com sacroileíte submetidos a terapia de radiofrequência ablativa

Sacroiliac joint (SIJ) pain is responsible for up to 40% of all cases of lumbar back pain. Objective Report the long-term efficacy of radiofrequency denervation for sacroiliac joint pain at six, twelve and eighteen months.Method Third-two adults’ patients with sacroiliac join pain diagnosis were included for a prospective study. Primary outcome measure was pain intensity on the Numeric Rating Scale (NRS). Secondary outcome measure was Patient Global Impression of Change Scale (PGIC).Results Short-term pain relief was observed, with the mean NRS pain score decreasing from 7.7 ± 1.8 at baseline to 2.8 ± 1.2 at one month and to 3.1 ± 1.9 at six months post-procedure (p < 0.001). Long-term pain relief was sustained at twelve and eighteen months post-procedure, with NRS pain remaining at 3.4 ± 2.1 and 4.0 ± 2.7, respectively.Conclusion Radiofrequency denervation of the SIJ can significantly reduce pain in selected patients with sacroiliac syndrome.

A Sacroileíte pode ser responsável por até 40% dos casos de dor lombar crônica. Objetivo Análise da eficácia da denervação por radiofrequência na articulação sacro-ilíaca em seis, doze e dezoito meses.Método Trinta e dois pacientes com diagnóstico de sacroileíte foram incluídos em estudo prospectivo. O prognóstico primário foi avaliado pela escala visual analógico (NRS). O prognóstico secundário foi avaliado pela escala de impressão global de mudança pelo paciente (PGIC).Resultados Melhora a curto prazo da dor foi observada, com redução media na NRS de 7,7 ± 1,8 para 2,8 ± 1,2 após 1 mês e para 3,1 ± 1,9 em 6 meses do procedimento (p < 0,001). Após 12 e 18 meses, o NRS manteve-se 3,4 ± 2,1 e 4,0 ± 2,7, respectivamente.Conclusão A denervação da articulação sacro-ilíaca por radiofrequência pode reduzir significativamente a dor em pacientes com sacroileíte.

The surgical neurovascular anatomy relating to partial and complete sacral and sacroiliac resections: a cadaveric, anatomic study.

PURPOSE: Pelvic and sacral surgeries are considered technically difficult due to the complex multidimensional anatomy and the presence of significant neurovascular structures. Knowledge of the key neurovascular anatomy is essential for safe and effective execution of partial and complete sacral resections. The goal of this anatomic, cadaveric study is to describe the pertinent neurovascular anatomy during these procedures. METHODS: Three embalmed human cadaveric specimens were used. Sacrectomies and sacroiliac joint resections were simulated and the structures at risk were identified. Both anterior and posterior approaches were evaluated. RESULTS: During sacroiliac joint resection, L5 nerve roots are at high risk for iatrogenic injury; the vasculatures at greatest risk are the common iliac vessels and internal iliac vessels with L5-S1 and S1-S2 high sacrectomies. Minor bleeding risk is associated with S2-S3 osteotomy because of the potential to damage superior gluteal vessels. S3-S4 osteotomy presents a low risk of bleeding. Adjacent nerve roots proximal to the resection level are at high risk during higher sacrectomies. CONCLUSIONS: Several sacrectomy techniques are available and selection often depends on the specific case and surgeon preference; nevertheless, anatomic knowledge is extremely important. Considering the highly variable anatomic relations of the vascular bundles, a preoperative evaluation with CT or MRI with vascular reconstruction may be helpful to decrease bleeding risk by preemptively binding the internal iliac vessels in cases where higher tumors are present. To decrease the risk of damaging nerve roots, it is recommended to perform the resection as close to the involved foramina as possible.

Spine epidural and sacroiliac joints injections--when and how to perform.

OBJECTIVES: To review the state-of-the-art of image-guided techniques used to treat painful syndromes of the lower back, their indications, how they should be performed, their related risks and the expected results. METHODS: We describe the actual standards about image-guided infiltrative therapies both on spine and on sacroiliac joints. RESULTS: Both spinal epidural and sacroiliac injections appear useful in a large percentage of treated patients to get control of the perceived pain. Performing these therapies under CT or fluoroscopic guidance is the best and safest way to obtain satisfactory results because it is possible to target the use of drugs directly to the involved painful structures. CONCLUSIONS: Image-guided injections of the epidural space and of the sacroiliac joints are effective techniques for the treatment of pain; their effectiveness is sometimes not lasting for long periods of time but considering the low associated risk when performed by trained personnel, they can be easily repeated.

Cadaveric study of sacroiliac joint innervation: implications for diagnostic blocks and radiofrequency ablation.

BACKGROUND AND OBJECTIVES: Optimization of clinical outcomes of lateral branch radiofrequency ablation or blocks for sacroiliac joint (SIJ) pain requires precise nerve localization; however, there is a lack of comprehensive morphological studies. The objectives of this cadaveric study were to document SIJ innervation relative to bony landmarks in 3 dimensions and to identify reference points visible under ultrasound and fluoroscopy for optimal needle placement. METHODS: In 25 cadaveric hemipelves, L5-S4 lateral branches were exposed, digitized, and modeled in 3 dimensions. The models were used to compare innervation patterns between specimens and to quantify the distances of the nerves innervating the SIJ relative to the transverse sacral tubercles (TSTs) and posterior sacral foramina. Quadrants of origin of the nerves were recorded. RESULTS: The SIJ was innervated by the posterior sacral network: S1-S2 contributed in all specimens, S3 in 88%, L5 in 8%, and S4 in 4%. Most frequently, the lateral branch(es) emerged from the inferolateral S1, superolateral and inferolateral S2, and superolateral S3 quadrants. All TSTs were easily identifiable elevations that were used to landmark the nerves innervating the SIJ. The majority of branches of the posterior sacral network crossed the lateral sacral crest between TST1-3, with the greatest concentration between TST2-3. Only 3 specimens had a branch superior or inferior to these landmarks. CONCLUSIONS: Based on the innervation pattern and using bony landmarks identifiable under ultrasound and fluoroscopy, 2 radiofrequency ablation techniques were proposed. Further research is required to determine the accuracy and reliability of needle placement and to evaluate clinical outcomes.

The anatomy of the lateral branches of the sacral dorsal rami: implications for radiofrequency ablation.

BACKGROUND: The sacroiliac joint (SIJ) is a major source of pain in patients with chronic low back pain. Radiofrequency ablation (RFA) of the lateral branches of the dorsal sacral rami that supply the joint is a treatment option gaining considerable attention. However, the position of the lateral branches (commonly targeted with RFA) is variable and the segmental innervation to the SIJ is not well understood. OBJECTIVES: Our objective was to clarify the lateral branches' innervation of the SIJ and their specific locations in relation to the dorsal sacral foramina, which are the standard RFA landmark. METHODS: Dissections and photography of the L5 to S4 sacral dorsal rami were performed on 12 hemipelves from 9 donated cadaveric specimens. RESULTS: There was a broad range of exit points from the dorsal sacral foramina: ranging from 12:00 - 6:00 position on the right side and 6:00 - 12:00 on the left positions. Nine of 12 of the hemipelves showed anastomosing branches from L5 dorsal rami to the S1 lateral plexus. LIMITATIONS: The limitations of this study include the use of a posterior approach to the pelvic dissection only, thus discounting any possible nerve contribution to the anterior aspect of the SIJ, as well as the possible destruction of some L5 or sacral dorsal rami branches with the removal of the ligaments and muscles of the low back. CONCLUSION: Widespread variability of lateral branch exit points from the dorsal sacral foramen and possible contributions from L5 dorsal rami and superior gluteal nerve were disclosed by the current study. Hence, SIJ RFA treatment approaches need to incorporate techniques which address the diverse SIJ innervation.