Cervical Zygapophysial Joint Research Articles

Effectiveness of Intermediate Cervical Plexus Block in Whiplash-Associated Disorder: A Prospective Observational Trial in Fifty Patients

BACKGROUND: Whiplash trauma can result in a range of symptoms, including chronic neck pain, headache, facial pain, upper back pain, and tinnitus, which comprises whiplash-associated disorder (WAD). Intermediate cervical plexus block (iCPB) is a novel intervention that targets the upper cervical nerves and anecdotal reports suggest benefits in WAD. OBJECTIVES: We hypothesized that the cervical plexus may have a role in the pathogenesis of WAD and blocking the cervical plexus may provide analgesia. STUDY DESIGN: Prospective observational trial. SETTING: Tertiary pain medicine unit at a university teaching hospital. METHODS: Adult patients who presented with refractory chronic neck pain following whiplash were included in a prospective observational trial. The pragmatic trial studied the effectiveness of 2 sequential cervical plexus blocks (iCPB with local anesthetic [iCPB-LA] and iCPB with steroid and LA mixture [iCPB-Steroid]) in refractory chronic neck pain following whiplash. Patients who reported < 50% relief at 12 weeks after iCPB-LA were offered iCPB-Steroid. Primary outcome was “neck pain at its worst in the last 24 hours” at 12 weeks. Secondary outcomes included change in neck disability index, employment status, and mood. RESULTS: After excluding cervical zygapophyseal joint dysfunction, 50 patients underwent the iCPB-LA between June 2020 and August 2022. Five patients reported > 50% relief (durable relief) at 12 weeks and 3 patients were lost to follow-up. Forty-two patients received iCPB-Steroid. iCPB-Steroid was associated with significant reduction in neck pain, neck disability, and improvement in mood at 12 weeks when compared to the block with LA. In addition, iCPB-Steroid was associated with significant reduction in neck pain and disability at 24 weeks. Due to functional improvement, 34 patients (34/50, 78%) were able to maintain employment. LIMITATIONS: This is an open-label, observational, single-center study in a limited cohort under a single physician. Cervical facet joint dysfunction was ruled out clinically and radiologically. CONCLUSIONS: Cervical plexus may play a central role in the pathogenesis of WAD. iCPB could potentially be a treatment option in this cohort. KEY WORDS: Intermediate cervical plexus block, whiplash, trigemino-cervical complex, whiplash-associated disorder, neck pain, chronic headache

Prospective Observational Trial of Intra-Articular Cervical Zygapophyseal Joint Corticosteroid Injections in Patients with Increased Peri-Zygapophyseal Joint MRI Short Tau Inversion Recovery Signal: A Pilot Study

Prospective Observational Trial of Intra-Articular Cervical Zygapophyseal Joint Corticosteroid Injections in Patients with Increased Peri-Zygapophyseal Joint MRI Short Tau Inversion Recovery Signal: A Pilot Study

Cervical medial branch block progression to radiofrequency neurotomy: A retrospective clinical audit

BackgroundChronic axial neck pain (CANP) due to zygapophysial joint arthropathy is best diagnosed via cervical medial branch block (MBB). However, the paradigm by which MBB is used to select patients for cervical radiofrequency neurotomy (RFN) is contested. Dual diagnostic cervical MBB with a minimum of ≥80% pain relief to diagnose cervical zygapophysial joint pain has been accepted by some Medicare Local Coverage Determinations as the method for selecting patients for cervical RFN. There are some who would argue that the utility of the dual diagnostic MBB and the ≥80% pain relief cut off lacks utility in clinical practice. The suspicion being those who progress from MBB1 to MBB2 will then flow from MBB2 to RFN without fail. Does clinical practice using dual diagnostic MBBs and using an ≥80% pain relief cut off reduce patient eligibility for cervical RFN after both MBB1 and MBB2? MethodsA retrospective clinical audit was carried out at an academic institution spine center from January 1st to December 31st, 2019. Charts were selected based on Current Procedural Terminology codes for MBB, then included if the cervical medial branches were targeted. Charts were then reviewed for procedural progression. Results21/51 (24%, 95% Confidence Interval 12-35%) patients progressed from MBB1 to MBB2. Of those 21 patients, 13 patients progressed from MBB2 to RFN (62%, 95% CI 41-83%). In total, 13/51 (14%, 95% CI 14-37%) patients who were initially suspected to have CANP due to zygapophysial joint pain progressed to RFN. Both MBB1 and MBB2 hindered the progression of 30/51 patients (59%, 95% CI 45-72%) and 8/21 patients (38%, 95% CI 17-59%), respectively. ConclusionBoth MBB1 and MBB2 served to filter patients from progression to RFN using dual MBBs with an ≥80% pain relief cutoff.

Patient Expectancy Does Not Predict Success or Failure of Thermal Neurotomy for Persistent Zygapophysial and Sacroiliac Joint Pain.

The placebo effect is important in determining the outcome of the treatment of pain for which expectancy and context are the main contributors. The variable success of thermal neurotomy spinal pain procedures is often seen as evidence of the placebo effect. Conversely, proponents of pain procedures explain poorer outcomes by technical procedure deficiencies, including inadequate diagnosis. This cohort study set out to determine whether patient expectancy is a contributing factor in the outcome of thermal neurotomy to the cervical, thoracic, and lumbar zygapophysial and sacroiliac joints. This single-practitioner, single-site retrospective analysis of prospectively gathered cohort data of 549 patients evaluated the impact of patient preprocedure expectancy (rated on a simple 0-10 or 0-4 numerical rating scale) on outcomes in a large consecutive series of patients who had undergone thermal neurotomy treatment between 2009 and 2019. In addition, a portion of patients were asked to what extent they hoped for or desired a good outcome. Successful pain relief (≥75% reduction from baseline) was not associated with a higher preprocedure expectancy than were failed procedures. Hope and desire demonstrated no impact on the positive or negative impact of the procedure. Altogether, patient expectation of outcome, hope, and desire are not associated with the outcome of effective pain relief by thermal neurotomy that has been performed to the appropriate and commonly available technical standards. Further work is needed to determine the influence of patient expectation across a range of pain intervention modalities.

Fetal cervical zygapophysial joint with special reference to the associated synovial tissue: a histological study using near-term human fetuses

Human fetal cervical vertebrae are characterized by the large zygapophysial joint (ZJ) extending posteriorly. During our recent studies on regional differences in the shape, extent, and surrounding tissue of the fetal ZJ, we incidentally found a cervical-specific structure of synovial tissues. This study aimed to provide a detailed evaluation of the synovial structure using sagittal and horizontal sections of 20 near-term fetuses. The cervical ZJ consistently had a large cavity with multiple recesses at the margins and, especially at the anterior end, the recess interdigitated with or were located close to tree-like tributaries of the veins of the external vertebral plexus. In contrast to the flat and thin synovial cell lining of the recess, the venous tributary had cuboidal endothelial cells. No or few elastic fibers were identified around the ZJ. The venous-synovial complex seems to be a transient morphology at and around birth, and it may play a role in the stabilization of the growing cervical ZJ against frequent spontaneous dislocation reported radiologically in infants. The venous-synovial complex in the cervical region should be lost and replaced by elastic fibers in childhood or adolescence. However, the delayed development of the ligament flavum is also likely to occur in the lumbar ZJ in spite of no evidence of a transient venous-synovial structure. The cuboidal venous endothelium may simply represent the high proliferation rate for the growing complex.

Fluoroscopically-Guided Cervical Zygapophyseal Therapeutic Joint Injections May Reduce the Need for Radiofrequency Neurotomy

Background: There is a paucity of literature studying therapeutic intraarticular zygapophyseal (commonly referred to as facet) joint injections in the atraumatic patient population. As a result of this, intraarticular injections have been dismissed as a possible treatment for cervical zygapophyseal joint-mediated pain. Radiofrequency neurotomy (RFN) is currently the accepted treatment for facet joint neck pain. Objective: This prospective observational study investigated injection response in an atraumatic population to determine treatment viability and whether injections reduce the need for RFN in neck pain patients. Study Design: Observational case series study. Setting: This study took place in the outpatient clinic of a private practice. Methods: The double-block paradigm (DBP) was used to determine if symptoms were zygapophyseal joint-mediated. Lidocaine and bupivacaine diagnostic injections were used. Participants passing the DBP underwent fluoroscopically-guided cervical zygapophyseal joint injections (betamethasone and 1% lidocaine) and 1 year of follow-up. Outcomes were a Verbal Numeric Scale score (VNS) > 2, 50% decrease in VNS, patient-reported improvement, and opioid use at the 1-year follow-up. Results: One hundred and eighteen patients were enrolled; 51 passed the DBP. These 51 patients underwent injections. Forty-four patients (59 joints) were surveyed 1 year later with 7 follow-up losses. Thirty-four of 59 joints showed ≥ 2-point VNS reductions or ≥ 50% overall symptomatic improvement after 1 year. Twenty-four of 44 ceased narcotics use. Limitations: The limitations of this research included the lack of randomization and blinding, smaller sample size, and reliance on subjective reporting from the participants both immediately after the procedures and at follow-up. As this was a prospective observational study, there is the possibility of unintended bias by both patients as well as the authors. Conclusion: Cervical zygapophyseal joint injections may reduce the need for RFN; additional studies are required. Key words: Neck pain, facet joint, cervical zygapophyseal joint injections, radiofrequency neurotomy

Fear-Avoidance Beliefs in Chronic Cervical Zygapophyseal Joint Pain Relieve With Medial Branch Block

Background: Chronic posterior neck pain is common, affecting 50–75% of people for 1 year or longer. The zygapophyseal joint is reported to be one of most common causative factors. The fear-avoidance is a model that describes how individuals develop chronic pain as a result of avoidant behaviour based on fear. Previous studies shown that medial branch block (MBB) and radio frequency neurotomy were effective for intractable pain.Material And Method: Case 1, TMK, Male, 57 yo, left posterior neck pain, VAS neck 7-8, NDI 46 %, no radiating pain, no neurological deficit. FABQ-PA score showed high fear (60%). Physical examination provokes facet joint pain. Neuroimaging revealed facet degeneration on T1WI and T2WI MRI. Case 2, RDW, Male, 45 yo, left posterior neck pain, VAS neck 8-9, NDI 40 %, no radiating pain, no neurological deficit. FABQ-PA score showed high fear (63%). Physical examination provokes facet joint pain. Neuroimaging revealed facet degeneration on T1WI and T2WI MRI. Case 3, TAY, Female, 52 yo, bilateral posterior neck pain, VAS neck 8-9, NDI 52 %, no radiating pain, no neurological deficit. FABQ-PA score showed high fear (60%). Physical examination provokes facet joint pain. Neuroimaging revealed facet degeneration on T1WI and T2WI MRI.Results: Our study reveals that C-MBB might ensure pain relief and decrease analgesic need. Physical activity at 1-, 3- and 6-months post-CMBB intervention were 65%, 60% and 68% of patients, respectively, gained >50% pain relief.Conclusion: Therapeutic MBB may provide an option for chronic high fear-avoidance beliefs pain of zygapophyseal joint.

Improving Fluoroscopic Visualization for Lower Cervical Medial Branch Blocks with a Modified Swimmer’s View: A Technical Report

Neural blockade of the cervical medial branches is a validated procedure in the diagnosis and treatment of cervical zygapophyseal joint pain. Fluoroscopic visualization of the lower cervical medial branch target zones (CMBTZs) in lateral view is sometimes challenging or not possible due to the patient's shoulders obscuring the target. Large shoulders and short necks often exacerbate the problem. Clear visualization is critical to accuracy and safety. We aim to describe a method for optimal fluoroscopic visualization of the lower CMBTZs using a modified swimmer's view. A technical report. A private practice. Discussion with accompanying fluoroscopic images of the cervical spine, focusing on the lateral aspects of the lower cervical articular pillars in both the traditional lateral view and modified swimmer's view. Four authors served as volunteers for undergoing fluoroscopic x-rays in both views. Visualization of each lower CMBTZ was attempted and stored. The most caudal, clearly visualized levels were compared in both views for each participant. Visualization of the lower CMBTZs can be successfully obtained with the modified swimmer's view and in select patients is superior to a lateral view. A limitation to this study is the design as a technical report. A future prospective study is warranted. Modified swimmer's view can serve as a primary method of visualizing the lower CMBTZs or an alternate view when a lateral view is unable to clearly demonstrate target landmarks. This can improve the ease, accuracy, and safety of performing diagnostic cervical medial branch blocks (CMBBs). Swimmer's view, cervical medial branch block, facet joint, fluoroscopy.

Fear-Avoidance Beliefs in Chronic Cervical Zygapophyseal Joint Pain Relieve With Medial Branch Block

Fear-Avoidance Beliefs in Chronic Cervical Zygapophyseal Joint Pain Relieve With Medial Branch Block

An ectopic intramedullary hematopoietic niche in a cervical spine meniscoid: a case report

We present the first documented case of an ectopic intramedullary hematopoietic niche within a cervical zygapophyseal joint intra-articular meniscoid. The meniscoid was identified in the cervical spine of an 81-year-old male cadaver, located at the dorsal aspect of the right C4-5 zygapophyseal joint, and was noted to be larger and more dense than other meniscoids during disarticulation and dissection of the joint. Histologically, the meniscoid contained hematopoietic cells surrounded by lamellar bone, and was lined with articular cartilage on the surface protruding into the joint cavity. Radiologically, the structure was hypointense on both T1- and T2-weighted magnetic resonance imaging sequences. The potential mechanisms underpinning development of this novel finding and the possible clinical implications are discussed in this report.

Clinical Diagnostic Tests versus Medial Branch Blocks for Adults with Persisting Cervical Zygapophyseal Joint Pain: A Systematic Review and Meta-Analysis.

Purpose: A systematic review and meta-analysis were performed to identify clinical tests for diagnosing cervical zygapophyseal joint pain (CZP) and to determine their diagnostic accuracy. Method: A search strategy was carried out to find relevant evidence published in CINAHL, Embase, MEDLINE, and PEDro from 1980 to January 1, 2015, pertaining to the clinical diagnosis of CZP. Quality assessment was completed using the Quality Assessment of Diagnostic Accuracy Studies-2. Results were analyzed to pool sensitivity and specificity and clarify diagnostic value. Results: Seven articles (n=463) were included for data synthesis and review. Intersegmental mobility tests were found to have the highest diagnostic accuracy, with pooled sensitivity of 0.91 (95% CI: 0.85, 0.94) and specificity of 0.74 (95% CI: 0.65, 0.81). The pooled sensitivity for mechanical sensitivity (palpation) was 0.88 (95% CI: 0.78, 0.95), and specificity was 0.61 (95% CI: 0.50, 0.71). Conclusion: Limited studies are available that discuss the clinical diagnosis of CZP, and significant heterogeneity is present in the available data. In this review, intersegmental mobility tests were found to be the most accurate. Clustering of tests, agreement on a reference standard, and further exploration of CZP referral patterns are recommended.

Radiofrequency Denervation Improves Health-Related Quality of Life in Patients with Thoracic Zygapophyseal Joint Pain.

To describe a practical approach for the diagnosis and treatment of thoracic zygapophyseal joint pain and to present preliminary clinical data on the effects of this treatment approach on health-related quality of life. An observational study. Specialist outpatient pain clinic in northern Sweden. Patients with long-term thoracic pain. We describe a method of radiofrequency denervation of thoracic zygapophyseal joints. We compared health-related quality of life between patients who underwent radiofrequency denervation of thoracic zygapophyseal joints and patients who underwent radiofrequency denervation for lumbar and cervical zygapophyseal joint pain. Treatment according to the Spine Intervention Society Guidelines was performed on the lumbar region in 178 patients and in the cervical region in 55 patients. Another 82 patients were treated in the thoracic region with our proposed technique. A survival plot of improvements in health-related quality of life revealed that all three treatments were effective in 65% or more of patients. The improvement in health-related quality of life was maintained for 12 or more months after treatment in 47% to 51% of patients. Our results suggest that radiofrequency denervation of thoracic zygapophyseal joint pain is as effective as radiofrequency denervation, the standard treatment, for lumbar and cervical zygapophyseal joint pain. If these results can be confirmed by other centers, radiofrequency denervation is likely to become more widely available for the treatment of thoracic zygapophyseal joint pain.

The influence of a depressed scapular alignment on upper limb neural tissue mechanosensitivity and local pressure pain sensitivity

BackgroundA depressed scapular alignment could lead to prolonged and repetitive stress or compression of the brachial plexus, resulting in sensitization of neural tissue. However, no study has investigated the influence of alignment of the scapulae on sensitization of upper limb neural tissue in otherwise asymptomatic people. In this case-control study, we investigate the influence of a depressed scapular alignment on mechanosensitivity of the upper limb peripheral nervous system as well as pressure pain thresholds (PPT). MethodsAsymptomatic individuals with neutral vertical scapular alignment (n = 25) or depressed scapular alignment (n = 25) participated. We measured the upper limb neurodynamic test (ULNT1), including assessment of symptom response and elbow range of motion (ROM), and PPT measured over upper limb peripheral nerve trunks, the upper trapezius muscle and overlying cervical zygapophyseal joints. ResultsSubjects with a depressed scapular reported significantly greater pain intensity (t = 5.7, p < 0.0001) and reduced elbow extension ROM (t = −2.7, p < 0.01) during the ULNT1 compared to those with a normal scapular orientation. Regardless of the location tested, the group presenting with a depressed scapular had significantly lower PPT compared to those with a normal scapular orientation (PPT averaged across all sites: normal orientation: 3.3 ± 0.6 kg/cm2, depressed scapular: 2.1 ± 0.5 kg/cm2, p < 0.00001). ConclusionsDespite being asymptomatic, people with a depressed scapular have greater neck and upper limb neural tissue mechanosensitivity when compared to people with a normal scapular orientation. This study offers insight into the potential development of neck-arm pain due to a depressed scapular position.

Immunohistochemical investigation of nerve fiber presence and morphology in elderly cervical spine meniscoids

Background ContextInnervation of anatomical structures is fundamental to their capacity to generate nociceptive impulses. Cervical spine meniscoids are hypothesized to be contributors to neck pain; however, their innervation is not comprehensively understood. PurposeThis study aimed to examine the presence and morphology of nerve fibers within cervical spine meniscoids and adjacent joint capsules. Study DesignThis is a cross-sectional study. Patient SampleThe sample consists of cervical hemispines of 12 embalmed cadavers (mean [standard deviation] age 82.9 [6.5] years, six female, six left). Either the right or the left half of the cervical spine (hemispine) of each cadaver was included in the sample. So six left sides and six right sides of the cadaver cervical spines made up the 12 hemispines that formed the sample. MethodsCervical spine meniscoids and adjacent joint capsules were excised from lateral atlantoaxial and cervical zygapophyseal (C2–C3 to C6–C7) joints (n=67), then paraffin embedded. Meniscoids were sectioned sagittally (5 µm), slide mounted, and immunohistochemistry was performed using primary antibodies to neurofilament heavy (NF-H) and pan-neurofilament (Pan-NF) to identify nerve tissue. The study was supported by institutional graduate student funding. The authors have no conflicts of interest to declare. ResultsSeventy-seven meniscoids (23 lateral atlantoaxial, 54 cervical zygapophyseal) were extracted and processed (154 sections in total). Sixty-four individual nerve fiber bundles were identified (26 NF-H positive, 38 Pan-NF positive) from 14 meniscoids. Nerves immunoreactive to both NF-H and Pan-NF were identified in 13 of 77 meniscoids (10 of 14 lateral atlantoaxial joint) from 11 joints (eight cadavers). Nerves were always located in joint capsules except three exclusively Pan-NF immunoreactive nerve fiber bundles from two adipose meniscoids. ConclusionsThe low nerve prevalence in elderly cervical spine meniscoids, with nerves only found in two adipose type meniscoids, suggests these structures may play a minimal role in cervical nociception generation in this demographic. The joint capsules, which were more frequently innervated, appear to be more likely generators of nociception in the elderly. Joint capsule nerves were mostly NF-H positive, indicating potential Aδ-fiber presence.

Chronic Whiplash Associated Disorders (WAD): Responses to Nerve Blocks of Cervical Zygapophyseal Joints.

This study explores the prevalence of facet joint pain in chronic Whiplash Associated Disorder (WAD). Forty-seven patients with chronic WAD were scheduled for medial branch blocks of the cervical spine. The patient's localization of the pain together with established pain maps guided to the first level of zygapophyseal joint to be tested. The joint was anesthetized by injecting bupivacaine (0.5 ml; 5 mg/ml) to the medial branches of the cervical dorsal rami above and below the joint. If a positive response was noted, the schedule continued with a double-blinded sequence with a placebo (saline) and bupivacaine. If a negative response was noted, other joint levels were anesthetized until all joints from C2 to C7 were tested. The responses were assessed using a visual analog scale (VAS) in a predefined protocol.The study was carried through with a definition of a positive response to a diagnostic block as a VAS decrease ≥50% compared with baseline during a minimum of 3 hours after the block. All other responses were regarded as negative. The data were also analyzed using a definition of a positive response as a VAS decrease ≥80%, and figures from this analysis are presented as the main result of the study. The study yielded 29% true positive responders, 60% non-responders, and 11% placebo responders. A substantial amount of patients with chronic WAD have their persistent pain emanating from cervical zygapophyseal joints.

Percutaneous radiofrequency rhizotomy for cervical zygapophyseal joint mediated neck pain: A retrospective review of outcomes in forty-four cases.

Percutaneous radiofrequency (RF) rhizotomy of the medial branches of the dorsal rami from the spinal nerves is the standard treatment for cervical zygapophyseal joint mediated pain. There is a paucity of data regarding the longevity of analgesia following this procedure. To determine the duration of complete pain relief, analgesic consumption and any adverse events following percutaneous cervical RF rhizotomy. Retrospective chart review of patients who had undergone percutaneous cervical RF rhizotomy for zygapophyseal joint mediated neck pain. Patient reviews were undertaken by the pain consultant at 6 weeks, 6 months and 1 year following the procedure. Where follow-up was incomplete, the patient was assumed only to have had pain relief until their last review where complete pain relief had been documented. Analgesic consumption and any adverse events were recorded. The data was analysed using Microsoft Excel®. At 12 months 63.64% of patients were pain free. Median duration of complete pain relief was 52 weeks. Patients who experienced pain relief had ceased using prescription analgesia by their 6 week review. There were no repeat cervical RF rhizotomies, procedure related infections or unplanned hospital admissions. Percutaneous cervical RF rhizotomy is an effective treatment for cervical zygapophyseal joint mediated neck pain.

Chapter 32 - Functional anatomy of the spine

Among other important features of the functional anatomy of the spine, described in this chapter, is the remarkable difference between the design and function of the cervical spine and that of the lumbar spine. In the cervical spine, the atlas serves to transmit the load of the head to the typical cervical vertebrae. The axis adapts the suboccipital region to the typical cervical spine. In cervical intervertebrtal discs the anulus fibrosus is not circumferential but is crescentic, and serves as an interosseous ligament in the saddle joint between vertebral bodies. Cervical vertebrae rotate and translate in the sagittal plane, and rotate in the manner of an inverted cone, across an oblique coronal plane. The cervical zygapophysial joints are the most common source of chronic neck pain. By contrast, lumbar discs are well designed to sustain compression loads, but rely on posterior elements to limit axial rotation. Internal disc disruption is the most common basis for chronic low-back pain. Spinal muscles are arranged systematically in prevertebral and postvertebral groups. The intrinsic elements of the spine are innervated by the dorsal rami of the spinal nerves, and by the sinuvertebral nerves. Little modern research has been conducted into the structure of the thoracic spine, or the causes of thoracic spinal pain.

The anatomy and morphometry of cervical zygapophyseal joint meniscoids.

Meniscoids are folds of synovial membrane that project into the articular cavities of zygapophyseal joints throughout the cervical spine. These structures have been implicated in musculoskeletal neck pain; however, their anatomy has not been extensively investigated. The purpose of this study was to explore the morphometry and composition of the cervical zygapohyseal joint meniscoids. Twelve adult cadaveric hemi-spines were dissected and their C2-3 to C6-7 zygapophyseal joints disarticulated (six female; six left; mean 81.5 years, SD 7.3 years). Meniscoids were identified and their surface area, protrusion length and articular cartilage degeneration measured. Specimens were then sectioned sagittally, stained with haematoxylin and eosin, and examined with a light microscope. Data were analysed descriptively and using non-parametric hypothesis testing (significance p < 0.05). Meniscoids were identified in 86% of zygapophyseal joints examined; 50% contained both ventral and dorsal meniscoids, 7% contained a ventral meniscoid only and 29% contained a dorsal meniscoid only. Meniscoids were classified as adipose (4%), fibrous (74%), or fibroadipose (22%) based upon histological composition. There were no significant associations between meniscoid size (surface area or protrusion length) and gender, position in joint, spinal level, or articular degeneration. Increased articular degeneration was associated with fibrous meniscoid classification. The morphological patterns observed, such as the association of fibrous meniscoids with cartilage degeneration, may provide insight into the significance of the zygapophyseal joint meniscoids in neck pathology. Further investigation is needed to explore the morphological qualities of these structures in a pathological population.

Formic acid demineralization does not affect the morphometry of cervical zygapophyseal joint meniscoids.

Demineralization can facilitate the dissection of soft tissue structures in inaccessible locations by softening surrounding bone so that it can be easily removed without risking damage to the structure of interest. However, it is unclear whether demineralization alters the morphometry of soft tissues if used for this purpose. We have therefore examined the effect of extended-immersion formic acid demineralization on the size and shape of cervical zygapophyseal joint meniscoids to evaluate its usefulness as a means of facilitating dissection and examination of soft tissue structures from bony regions. Four cadaveric cervical spines were dissected, and three randomly selected zygapophyseal joints from each spine (12 in total) were removed, disarticulated and immersed in 5% formic acid for 32 days. Each joint was examined using a surgical microscope and photographed, and meniscoid length and surface area measured at days 0, 4, 18, and 32. Measurements were made on magnified digital photographs, and each measurement was repeated three times to determine intra-rater reliability. Data were analyzed using repeated-measures analysis of variance. Significance was set at p < 0.05. There were no significant differences between any of the measures over time for all of the variables assessed (F = 0.302-1.576, p = 0.226-0.759, partial η (2) = 0.029-0.136). For all measurements, intra-rater reliability was high (intra-class correlation > 0.9). These results support the use of formic acid demineralization to facilitate the study of cervical spine meniscoids by dissection, as even after a period of extended immersion in the solution, the morphometry of the structures was not significantly altered. Findings may have implications for dissection studies of other meniscoid-like soft tissue structures that use formic acid demineralization.

Radio-Frequency Ablation Treatment of Chronic Neck and Low Back Pain Attributable to Facet Joints

Spine pain is a major cause of disability for which conservative treatment strategies are not universally effective. Radio-frequency ablation of nerves supplying the zygapophysial joints should be considered in selected patients for whom routine treatments do not provide acceptable relief. Following a brief discussion of the principles of radio-frequency therapy, we describe the relevant anatomy, appropriate patient selection, and basic procedural techniques for ablative therapies of the cervical and lumbar zygapophysial joints.