Clinical Anatomy and Measurement of the Medial Branch of the Spinal Dorsal Ramus

Anatomical Observation and Clinical Significance of the Medial Branch of the Lumbar Dorsal Rami

STUDY DESIGN

Anatomical study.

OBJECTIVE

This study aimed to elaborate on the anatomical characteristics of the medial branch of the lumbar dorsal rami and to discuss its possible clinical significance.

SUMMARY OF BACKGROUND DATA

Radiofrequency ablation targeting the medial branch of the lumbar dorsal rami has been increasingly used in the clinical management of facetogenic low back pain (FLBP). Nonetheless, attention is also being given to complications such as atrophy of the lumbar soft tissues and muscles. Therefore, a more detailed understanding of the innervation pattern on the facet joint may improve the precision of nerve ablation therapy for FLBP.

METHODS

An anatomical study of eight human specimens was carried out. The anatomic characteristics of the medial branch were observed and recorded.

RESULTS

The medial branch originates from the lumbar dorsal rami, running close to the root of the posterolateral side of the superior articular process of the inferior cone. When passed through the mamillo-accessory ligament, it turns direction to the medial and caudal side, running in the multifidus muscle. In our study, each medial branch sent out two to five branches along the way. All the medial branches in L1-L4 gave off one to two small branches when crossing the facet joint and innervated the joint of the lower segment. Nineteen medial branches (23.75%) gave off recurrent branches to innervate the joint at the upper segment.

CONCLUSION

The anatomical features of the medial branch remain similar in each lumbar segment. There are two types of joint branches, including the articular fibers that emanate from the medial branch as it runs along the medial border of the facet joint and the recurrent branch from the medial branch that innervates the upper facet joint. Moreover, an anastomotic branch was found in the medial branches between different segments.

Comparison of the Efficacy of Different Radiofrequency Techniques for the Treatment of Lumbar Facet Joint Pain: Combined with Anatomy

PURPOSE OF REVIEW

Lumbar facet pain is generally considered to be one of the major causes of chronic low back pain. Each lumbar facet joint is innervated by the medial branch of the posterior spinal nerve from its own level and above. Radiofrequency (RF) of the medial branch of the posterior branch of the spinal nerve is an effective method for the treatment of lumbar facet pain. RF technology is diverse, including traditional radiofrequency (TRF), pulsed radiofrequency (PRF), cooled radiofrequency (CRF), low-temperature plasma radiofrequency ablation (CA), and other treatment methods. The purpose of this paper is to compare the efficacy of different radiofrequency techniques and to analyze the reasons for this in the context of anatomy.

RECENT FINDINGS

There have been studies confirming the differences in efficacy of different RF techniques. However, most of the studies only compared two RF techniques, not four techniques, TRF, CRF, PRF, and CA, and did not analyze the reasons for the differences in efficacy. This article reviews the differences in the efficacy of the above four RF techniques, clarifies that the differences are mainly due to the inability to precisely localize the medial branch of the posterior branch of the spinal nerve, analyzes the reasons for the inability to precisely localize the posterior branch of the spinal nerve in conjunction with anatomy, and proposes that the development of RF technology for lumbar facet pain requires more in-depth anatomical, imaging, and clinical studies.

Percutaneous radiofrequency ablation and endoscopic neurotomy for lumbar facet joint syndrome: are they good enough?

OBJECTIVE

Lumbar facet joint (LFJ) syndrome is one of the common causes of low back pain (LBP). There are different views on percutaneous and endoscopic radiofrequency. The purpose of this systematic review and meta-analysis is to explore the therapeutic effect of radiofrequency ablation on LBP originating from LFJ and compare the therapeutic effect of percutaneous radiofrequency ablation and endoscopic neurotomy.

METHODS

We included randomized controlled trials which compared the efficiency of percutaneous radiofrequency ablation and conservative treatment (sham procedures, facet joint injection, physiotherapy, exercise, or oral medication) or compared the efficiency of percutaneous radiofrequency ablation and endoscopic neurotomy for LFJ syndrome. We searched in PubMed and Web of Science from inception to March 27, 2023. Meta-analysis was performed using RevMan 5.4 software.

RESULTS

A total of 11 randomized controlled trials were included. Among them, nine studies were used for evaluating efficiency of percutaneous radiofrequency ablation, and two studies were used for evaluating efficiency of endoscopic neurotomy. Pooled data from two studies reporting outcomes at 1 year did not show a benefit from facet joint denervation by comparing the percutaneous radiofrequency ablation and conservative treatment (standardized mean difference (SMD) = -0.87, 95% confidence interval (CI) [-2.10, 0.37], P = 0.17). There was no significant difference between percutaneous radiofrequency ablation and endoscopic neurotomy at 1-month follow-up (mean difference (MD) = -0.13, 95%CI [-0.18, -0.44], P = 0.41). At 12-month follow-up the pain relief in the endoscopic neurotomy was significantly better than that in the percutaneous radiofrequency ablation group (MD = 1.98, 95%CI [1.60, 2.36], P < 0 .0001).

CONCLUSION

The LBP was significantly relieved shortly after percutaneous radiofrequency ablation. Compared with percutaneous radiofrequency ablation, endoscopic neurotomy seems to have a longer effect. A longer follow-up period is needed to confirm its effectiveness.

Multifidus Denervation After Radiofrequency Ablation of the Medial Nerve Alters the Biomechanics of the Spine-A Computational Study

Radiofrequency ablation of the medial branch is commonly used to treat chronic low back pain involving facet joints, which accounts for 12% to 37% of the total cases of chronic low back pain. An adverse effect of this procedure is the denervation of the multifidus muscle, which may lead to its atrophy which can affect the spine and possibly disc degeneration. This study aims to quantify changes in joint angles and loading caused by multifidus denervation after radiofrequency ablation. AnyBody model of the torso was used to evaluate intervertebral joints in flexion, lateral bending, and torsion. Force-dependent kinematics was used to calculate joint angles and forces. These dependent variables were investigated in intact multifidus, unilateral, and bilateral ablations of L3L4, L4L5, and L5S1 joints. The results showed pronounced angular joint changes, especially in bilateral ablations in flexion, when compared with other cases. The same changes' trend from intact to unilaterally then bilaterally ablated multifidus occurred in joint angles of lateral bending. Meanwhile, joint forces were not adversely affected. These results suggest that multifidus denervation after radiofrequency ablation affects spinal mechanics. Such changes may be associated with abnormal tissue deformations and stresses that can potentially alter their mechanobiology and homeostasis, thereby possibly affecting the health of the spine.

Facet Joint Syndrome: Pathophysiology, Diagnosis, and Treatment

Facet joint osteoarthritis (OA) is the most frequent form of facet joint syndrome. Medical history, referred pain patterns, physical examination, and diagnostic imaging studies (standard radiographs, magnetic resonance imaging, computed tomography and single-photon emission computed tomography) may suggest but not confirm lumbar facet joint (LFJ) syndrome as a source of low back pain (LBP). However, the diagnosis and treatment of facet joint syndrome is still controversial and needs further study. It is widely acknowledged that block with local anesthetic is perhaps the most effective method to establish a diagnosis of pain from LFJ. Particularly, there are different rates of success among different populations selected for diagnostic block with various positive criteria. Currently, in addition to conservative treatments for pain such as painkillers, functional exercises, and massage, there are many other methods, including block, denervation of the nerves that innervate the joints by radiofrequency, freezing or endoscopy, and injections. Due to the limited duration of pain relief from neurolysis of medial branch, many scholars have recently turned their targets to dorsal roots and LFJ capsules. Therefore, we reviewed the latest research progress of facet joint syndrome from diagnosis to treatment.

Facet overhang: A novel parameter in the pathophysiology of multifidus muscle atrophy

The relationship between degenerative zygapophysial joint (facet) arthropathy and multifidus muscle atrophy has not been rigorously evaluated. The purpose of this study was to determine if specific morphological features of degenerative facet arthropathy are correlated with multifidus muscle atrophy. We retrospectively reviewed medical records and imaging studies of patients with lumbar spinal stenosis. Facet overhang, bridging osteophyte formation, facet effusion, and facet angles were evaluated by univariable and multivariable regression to identify independent associations with deep and superficial parts of the multifidus total cross-sectional area (tCSA), functional cross-sectional area (fnCSA), and fatty infiltration (FI). Facet overhang was classified as severe in 50 females (53.2%) versus 56 males (36.9%) (p = 0.030). Severity of facet overhang and female sex were independently associated with smaller deep part of the multifidus tCSA and fnCSA as well as higher FI, reflecting greater atrophy of the deep region compared to total muscle mass. In comparison, severe facet overhang (p < 0.001; OR = 3.47, 95% CI = 2.13-5.66) and female sex (p < 0.001; OR = 4.19, 95% CI = 2.58-6.79) were independently associated only with higher superficial part of the multifidus FI, reflecting muscle steatosis without significant lean muscle atrophy. In patients with degenerative lumbar spinal stenosis, facet overhang is an independent risk factor for deep part of the multifidus atrophy. Bridging osteophyte formation, facet effusion, and facet angles were not independently associated with deep part of the multifidus atrophy.

Baastrup’s Disease in Pediatric Gymnasts

Baastrup’s disease is a rare, often misdiagnosed, and causes back pain in children. It is characterized by degenerative changes of both spinous processes and interspinous soft tissues between two adjacent vertebrae. Repetitive spinal movements in the sagittal plane predispose injury to posterior elements of the spine. Chronic flexion and extension strain the interspinous ligament, causing the neighboring spinous processes to adjoin. Patients typically report midline back pain in the lumbar region, which radiates both cephalad and caudad but not laterally. Pain is aggravated by extension and palpation and is alleviated with flexion. Some children with Baastrup’s do not experience pain but present with swelling along the spinous processes. Diagnosis is dependent on distinctive radiologic findings and exam features. Increased interspinous spaces and bone remodeling may be observed. While the current treatment for pain associated with Baastrup’s is directed towards physical therapy, massage therapy, nonsteroidal anti-inflammatory medications, muscle relaxants, and rest from activity, this is the first report of children undergoing interventional modalities for the treatment of back pain associated with Baastrup’s disease. We present two unique pediatric cases of female gymnasts with Baastrup’s disease who were successfully treated by two different techniques: interspinous ligament injection and medial branch block.

How I do it? Full endoscopic lumbar rhizotomy for chronic facet joint pain due to failed back surgery syndrome

BACKGROUND

Failed back surgery syndrome (FBSS) is a general term for persistent postoperative back pain with or without accompanying radicular pain. FBSS may present as chronic facet joint pain.

METHODS

We introduced full endoscopic lumbar rhizotomy for patients suffering from facet joint pain due to FBSS. Facet joint block was introduced into the facet joint to determine whether pain improved after the injection.

CONCLUSION

With full endoscopic lumbar rhizotomy, the surgeon can identify the regions involved more clearly and directly. Although it is an invasive procedure, it provides a more effective and safe treatment for patients with FBSS-related facet joint pain.

Percutaneous spinal endoscopy with unilateral interlaminar approach to perform bilateral decompression for central lumbar spinal stenosis: radiographic and clinical assessment

Background

Recently, a percutaneous spinal endoscopy unilateral posterior interlaminar approach to perform bilateral decompression has been proposed for use in treatment of lumbar spinal stenosis, As a development and supplement to traditional surgery, its advantages regarding therapeutic effects and prognosis, such as minor soft tissue damage, little intraoperative blood loss, and a quick return to daily life. However, there are few analyses of this surgery with a follow-up of more than 1 year,we conducted this study in order to quantitatively investigate radiographic and clinical efficacies of this surgery for central lumbar spinal stenosis.

Materials and methods

Forty-six patients with central lumbar spinal stenosis were enrolled from January 2017 to July 2018. The visual analog scale (VAS) for back pain and leg pain, Oswestry disability index (ODI), modified MacNab criteria were used to evaluate clinical efficiency at preoperative and postoperative time points. The intervertebral height index (IHI), cross-sectional area of the spinal canal (CSAC), calibrated disc signal (CDS) and spinal stability were examined to assess radiographic decompression efficiency via magnetic resonance imaging and X-ray at preoperative and postoperative time points.

Results

The VAS score for lower back pain and leg pain improved from 7.50 ± 0.78 to 1.70 ± 0.66 and from 7.30 ± 0.79 to 1.74 ± 0.68, respectively, and the ODI improved from 72.35 ± 8.15 to 16.15 ± 4.51. In terms of modified MacNab criteria, 91.3% of the patients achieved good or excellent outcomes. Furthermore, significant changes after surgery were observed for the percentage of CSAC, increasing from 125.3 ± 53.9 to 201.4 ± 78 mm²; however, no significant differences were observed for the remaining measurement indicators.

Conclusions

The clinical and radiographic efficacies of this surgery for central lumbar spinal stenosis were good in short-term follow-up, and this surgery did not cause meaningful changes in IHI, CDS, and spine stability in short-term follow-up. The effect of long-term follow-up needs further investigation.

In vivo measurements of medial branch nerve depth and adjacent osseous structures for ablation of facet-related back pain: Predictors for patient candidacy

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The average distance from skin-to-MB at a 15 angle to the skin and the average thickness of the pedicles both increased as the lumbar level increased.

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The linear regression model returned BMI, vertebral level, and gender as significant predictors of MB depth.

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The MB resides 107 mm or less in depth when measured at a 15° angulation from the skin in > 95% of patients.

Background

Methods

Results

Conclusions

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group

BACKGROUND

The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.

METHODS

After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.

RESULTS

17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).

CONCLUSIONS

Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Ultrasound practice for chronic pain procedures: A comprehensive review

Chronic pain management techniques have evolved in recent years. With regard to this, ultrasound (US) technology has become a standard for most acute pain procedures and essential for postsurgical pain relief and enhanced recovery after surgery protocols. This manuscript summarizes clinical studies evaluating US use for chronic pain management and compares efficacy with standard techniques including fluoroscopy (FL). US possesses several unique benefits when compared with FL, including elimination of radiation exposure while providing similar clinical outcomes. In summary, US use for chronic pain procedures is emerging as a viable, safe, and effective modality. Additional studies are needed to best appreciate US and its role in chronic pain management.

T12 Dorsal Root Ganglion Stimulation to Treat Chronic Low Back Pain: A Case Series

INTRODUCTION

Dorsal root ganglion stimulation (DRG-S) is a neuromodulation technique for treating neuropathic pain syndromes. Research has demonstrated DRG-S to be more effective than conventional SCS in treating RSD/CRPS, particularly of the lower extremities. Results from recent case series and prospective studies suggest that DRG-S may be effective in treatment of pain syndromes considered to have non-neuropathic components and characteristics (e.g. nociceptive). There have been multiple, small studies demonstrating efficacy of DRG-S for axial low back pain. There has, however, been no consensus regarding the best location for DRG lead placement in the treatment of low back pain.

METHODS

Patients presenting with refractory low back pain in a private pain management practice were considered for DRG-S. Patients were provided a trial stimulator prior to potential implantation. Per standard practice, pain intensity, disability, general health status, and quality of life were followed using the visual analog scale (VAS), Oswestry Disability Index, EQ-5D index, and the SF-36 survey, respectively. Data were collected prior to implantation and at variable follow-ups after DRG-S initiation.

RESULTS

Seventeen consecutive patients presented with predominantly axial low back pain with/without a secondary component of lower extremity pain. All were trialed and subsequently implanted for DRG-S. Leads were placed at T12 to target the low back. Stimulation levels were set very low, below that of which patients experienced paresthesias. Last follow-up times averaged 8.3 months. More than half of the patients experienced pain relief ≥80%, with an average low back pain relief of 78% at last follow-up. Additionally, substantial improvements in physical and mental functioning, disability, and quality of life were reported.

CONCLUSIONS

T12 DRG-S can be an effective treatment for chronic axial low back pain. Stimulation results in reduced pain and disability, while improving quality of life. These outcomes can be achieved without paresthesias.

Anatomical description of anaesthetic spread after deep erector spinae block at L-4

INTRODUCTION

Thoracic erector spinae plane (ESP) block is now used for postoperative analgesia. However, although reports of lumbar ESP have been published, the anesthetic spread and mechanism of action of this technique remains unclear. We describe the lumbar ESP block technique and evaluate the spread of 20ml of solution administered at the level of the transverse process of L4 in a cadaver model.

METHODS

Observational study after 12 lumbar ESP blocks at L4 on a fresh cadaver model (6 bilaterally). The spread of 20ml of injected contrast solution was assessed by computed tomography in all 6 samples. Four of the samples were evaluated by anatomical study, 2 by plane dissection, and 2 others were frozen and cut into 2-2.5cm axial slices.

RESULTS

The injected solution spread from L2 to L5 in a cranio-caudal direction in the erector spinae muscle, reaching the facet joints medially and the thoracolumbar fascia laterally. In 33% of cases the solution did not spread anterior to the transverse process; in 51%, spread was minimal and did not affect the corresponding spinal nerves, and in 2 samples (16%), spread was extensive and reached the corresponding spinal nerves.

CONCLUSIONS

Lumbar ESP at L4 always acts on the posterior branches of the spinal nerves, but seldom spreads to the paravertebral space to block the spinal nerve.

Chronic localized back pain due to entrapment of cutaneous branches of posterior rami of the thoracic nerves (POCNES): a case series on diagnosis and management

Introduction and aim

Chronic back pain (CBP) may be caused by a variety of conditions including dysfunctional muscles, ligaments or intervertebral discs, improper movement of vertebral column joints, or nerve root compression. Recently, CBP was treated successfully in a patient having an entrapment of cutaneous branches of the posterior rami of the thoracic nerves, termed posterior cutaneous nerve entrapment syndrome (POCNES). Our aim is to describe clinical presentation, differential diagnosis, and management of patients with such a neuropathic pain syndrome.

Methods

This study analyzed prospectively obtained data from consecutive patients suspected of having POCNES, presenting to two Dutch hospitals between January 2013 and September 2016. Patients received a diagnostic 2–5 mL 1% lidocaine injection just below the thoracolumbar fascia. Pain was scored using a numerical rating scale (0 = no pain to 10 = worst possible pain). A >50% pain reduction was defined as success. A neurectomy was proposed if pain reduction was temporary or insufficient after one to three injections. Long-term treatment effect was determined using a verbal rating scale (VRS; 1 = very satisfied, no pain, to 5 = pain worse).

Results

Fourteen patients (12 women, median age 26, age range 18–73) were diagnosed with POCNES. Eighty-one percent (n=11) reported a >50% pain drop after injection (NRS pain scores of median 8.0 [IQR 7.0–8.0] to median 3.0 [IQR 1.5–3.5], P<0.001). In one patient, repeated injections were successful long-term (VRS score of 2). Two patients declined surgery, whereas the remaining eleven underwent a neurectomy that was successful in seven (64%). A 57% long-term efficacy (median 29 months follow-up, range 5–48, VRS score 1–2) was attained in the entire study population.

Conclusion

POCNES should be considered in the differential diagnosis of chronic localized back pain. A treatment regimen including injections and neurectomy of the specific cutaneous branch results in long-term pain relief in more than half of these patients.

Bipolar Radiofrequency Facet Ablation of the Lumbar Facet Capsule: An Adjunct to Conventional Radiofrequency Ablation for Pain Management

Radiofrequency facet ablation (RFA) has been performed using the same technique for over 50 years. Except for variations in electrode size, tip shape, and change in radiofrequency (RF) stimulation parameters, using standard, pulsed, and cooled RF wavelengths, the target points have remained absolutely unchanged from the original work describing RFA for lumbar pain control. Degenerative changes in the facet joint and capsule are the primary location for the majority of lumbar segmental pathology and pain. Multiple studies show that the degenerated facet joint is richly innervated as a result of the inflammatory overgrowth of the synovium. The primary provocative clinical test to justify an RFA is to perform an injection with local anesthetic into the facet joint and the posterior capsule and confirm pain relief. However, after a positive response, the radiofrequency lesion is made not to the facet joint but to the more proximal fine nerve branches that innervate the joint. The accepted target points for the recurrent sensory branch ignore the characteristic rich innervation of the pathologic lumbar facet capsule and assume that lesioning of these recurrent branches is sufficient to denervate the painful pathologic facet joint. This report describes the additional targets and technical steps for further coagulation points along the posterior capsule of the lumbar facet joint and the physiologic studies of the advantage of the bipolar radiofrequency current in this location. Bipolar RF to the facet capsule is a simple, extra step that easily creates a large thermo-coagulated lesion in this capsule region of the pathologic facet joint. Early studies demonstrate bipolar RF to the facet capsule can provide long-term pain relief when used alone for specific localized facet joint pain, to coagulate lumbar facet cysts to prevent recurrence, and to get more extensive pain control by combining it with traditional lumbar RFA, especially when RFA is repeated.