A History of the Development of Radiofrequency Neurotomy.

Background: Chronic, recurrent neck pain is common and is associated with high pain intensity and disability, which is seen in 14% of the adult general population. Controlled studies have supported the existence of cervical facet or zygapophysial joint pain in 36% to 67% of these patients. However, these studies also have shown false-positive results in 27% to 63% of the patients with a single diagnostic block. There is also a paucity of literature investigating therapeutic interventions of cervical facet joint pain. Study Design: A systematic review of cervical facet joint interventions. Objective: To evaluate the accuracy of diagnostic facet joint nerve blocks and the effectiveness of cervical facet joint interventions. Methods: Medical databases and journals were searched to locate all relevant literature from 1966 through December 2008 in the English language. A review of the literature of the utility of facet joint interventions in diagnosing and managing facet joint pain was performed according to the Agency for Healthcare Research and Quality (AHRQ) criteria for diagnostic studies and observational studies and the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials. Level of Evidence: The level of evidence was defined as Level I, II, or III based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF). Outcome Measures: For diagnostic interventions, studies must have been performed utilizing controlled local anesthetic blocks which achieve at minimum 80% relief of pain and the ability to perform previously painful movements. For therapeutic interventions, the primary outcome measure was pain relief (short-term relief up to 6 months and long-term relief greater than 6 months) with secondary outcome measures of improvement in functional status, psychological status, return to work, and reduction in opioid intake. Results: Based on the utilization of controlled comparative local anesthetic blocks, the evidence for the diagnosis of cervical facet joint pain is Level I or II-1. The indicated evidence for therapeutic cervical medial branch blocks is Level II-1. The indicated evidence for radiofrequency neurotomy in the cervical spine is Level II-1 or II-2, whereas the evidence is lacking for intraarticular injections. Limitations: A systematic review of cervical facet joint interventions is hindered by the paucity of published literature and lack of literature for intraarticular cervical facet joint injections. Conclusions: The evidence for diagnosis of cervical facet joint pain with controlled comparative local anesthetic blocks is Level I or II-1. The indicated evidence for therapeutic facet joint interventions is Level II-1 for medial branch blocks, and Level II-1 or II-2 for radiofrequency neurotomy. Key words: Chronic neck pain, cervical facet or zygapophysial joint pain, cervical medial branch blocks, controlled comparative local anesthetic blocks, cervical radiofrequency neurotomy, cervical intraarticular facet joint injections

In this study, a porcine model was used to study whether a nerve reaction in the anulus fibrosus of a lumbar disc or in a facet joint capsule could cause a muscular response in the multifidus musculature. To determine if there is an interrelationship between the intervertebral disc and facet joint innervation and the multifidus musculature as a possible pain mechanism. The innervation of the anulus fibrosus of the intervertebral disc and the capsule of the facet joint is well described in the literature, although the functions of these nerves are poorly understood. An interrelationship between this innervation and the paraspinal musculature has not been previously described. Fifteen adult pigs were used to measure the electromyographic response in the multifidus musculature to electrical stimulation of the lateral region of the disc anulus and the facet joint capsule in the L1-L2 motion segment. Motor unit action potentials were recorded using three sets of bipolar needle electrodes placed into the deepest fascicles of the multifidus, bilateral to the L2, L3, and L4 spinous processes. The effect of lidocaine injection into the facet joint and subperiosteal muscle detachment on the electromyographic response were studied. Stimulation of the disc anulus fibrosus induced reactions in the multifidus on multiple levels and on the contralateral side, whereas stimulation of the facet joint capsule induced reactions predominantly on the same side and segmental level as the stimulation. Introduction of lidocaine into the facet joint resulted in a significantly reduced electromyographic response to either stimulation, with the most drastic reduction seen when stimulating the facet joint capsule. Subperiosteal detachment of the paraspinal muscles prevented any muscular response. Stimulation of the disc and the facet joint capsule produced contractions in multifidus fascicles. The clinical implications are that there may be interactive responses between injured or diseased structures, i.e., disc or facet joints, and the paraspinal musculature. Activation of the multifidus muscles may have a stabilizing effect, constraining the motion of the lumbar spine. Longstanding muscular contraction may produce ischemic conditions and may be a potential source of pain.

Cervical therapeutic intraarticular facet joint injections, therapeutic medial branch blocks, and radiofrequency neurotomy have been applied in managing chronic neck pain of cervical facet joint origin. However, the effectiveness of these modalities continues to be debated. The purpose of this study was to determine the clinical effectiveness of therapeutic cervical medial branch blocks with or without steroids. A randomized, double-blind, controlled trial. An interventional pain management practice, a specialty referral center, a private practice setting in the United States. To evaluate the clinical outcomes of therapeutic cervical medial branch blocks with local anesthetic with or without steroids in managing chronic neck pain of facet joint origin. A total of 120 patients meeting inclusion criteria were included. All of the patients met the diagnostic criteria of cervical facet joint pain by means of comparative, controlled diagnostic blocks, with at least 80% relief. Group I consisted of cervical medial branch blocks with bupivacaine only and Group II consisted of cervical medial branch blocks with bupivacaine and steroid. Therapeutic cervical medial branch blocks with local anesthetic with or without steroids were administered. Main outcome measures included numeric pain scores, Neck Disability Index (NDI), opioid intake, and work status evaluated at baseline, 6, 12, 18, and 24 months. The one-year results of outcomes were published in 2008. This manuscript describes the 2-year results. Significant improvement was defined as at least 50% improvement in pain relief and/or functional status improvement. Patient outcomes were measured at baseline, 3, 6, 12, 18, and 24 months post-treatment with the Numeric Rating Scale (NRS), the Neck Disability Index (NDI), employment status, and opioid intake. Decrease of ≥ 50% of NRS scores and Oswestry scores were considered significant. Eighty-five percent of patients in Group I and 93% of patients in Group II showed significant pain relief (≥ 50%) at 2 years. The average number of treatments for 2 years was 5.7. The duration of average pain relief with each procedure was 17-19 weeks on average in both groups. Significant improvement of pain and function was demonstrated for 83 to 89 weeks over a period of 2 years. The study limitations include the lack of a placebo group. In this study, therapeutic cervical medial branch blocks instituted after the diagnosis, with controlled comparative local anesthetic blocks with 80% concordant pain relief, repeated approximately 6 times over a period of 2 years, provided significant improvement over a period of 2 years. NCT00332722.

Effective treatment of low back pain (LBP) originating in the lumbar and sacroiliac joints is difficult to achieve. The objective of the current study was to compare the clinical effectiveness of radiofrequency (RF) neurotomy versus conservative nonsurgical approaches for the management of chronic lumbar and sacroiliac joint pain. The PICOS framework was adhered to (P [population]: patients with a history of chronic function-limiting lumbar and sacroiliac joint pain lasting at least 6 months; I [intervention]: RF neurotomy; C [comparator]: other nonsurgical treatments; O [outcomes]: the Oswestry Disability Index (ODI), measurement for pain, and a quality of life (QoL) questionnaire; S [study design]: meta-analysis). Two trained investigators systematically searched Medline, Cochrane, EMBASE, and ISI Web of Knowledge databases for relevant studies published in English through March 2019. Patients treated with RF neurotomy (n = 528) had significantly greater improvement in ODI scores, pain scores and QoL measured by EQ-5D compared with controls (n = 457); however, significant heterogeneity was observed when data were pooled from eligible studies. In subgroup analyses, patients who received RF neurotomy had a significantly greater improvement in ODI scores compared with those with sham treatment. Patients treated with RF achieved significantly greater improvement in pain scores compared with controls who received sham treatment or medical treatment. In a subgroup analysis of pain in the sacroiliac joint and in lumbar facet joints, the RF neurotomy group achieved a significantly greater improvement in ODI score and pain scores compared with the control group. The ODI score and pain score were improved after 2 months of follow up in the analyses stratified by follow-up duration. Use of RF neurotomy as an intervention for chronic lumbar and sacroiliac joint pain led to improved function; however, larger, more directly comparable studies are needed to confirm this study's findings.

Nonrandomized controlled cohort. To characterize subaxial cervical facet joint kinematics and facet joint capsule (FJC) deformation during in vivo, dynamic flexion-extension. To assess the effect of single-level anterior arthrodesis on adjacent segment FJC deformation. The cervical facet joint has been identified as the most common source of neck pain, and it is thought to play a role in chronic neck pain related to whiplash injury. Our current knowledge of cervical facet joint kinematics is based on cadaveric mechanical testing. Fourteen asymptomatic controls and 9 C5-C6 arthrodesis patients performed full range of motion flexion-extension while biplane radiographs were collected at 30 Hz. A volumetric model-based tracking process determined 3-dimensional vertebral position with submillimeter accuracy. FJC fibers were modeled and grouped into anterior, lateral, posterior-lateral, posterior, and posterior-medial regions. FJC fiber deformations (total, shear, and compression-distraction) relative to the static position were determined for each cervical motion segment (C2-C3 through C6-C7) during flexion-extension. No significant differences in the rate of fiber deformation in flexion were identified among motion segments (P = 0.159); however, significant differences were observed among fiber regions (P < 0.001). Significant differences in the rate of fiber deformation in extension were identified among motion segments (P < 0.001) and among fiber regions (P = 0.001). The rate of FJC deformation in extension adjacent to the arthrodesis was 45% less than that in corresponding motion segments in control subjects (P = 0.001). In control subjects, FJC deformations are significantly different among vertebral levels and capsule regions when vertebrae are in an extended orientation. In a flexed orientation, FJC deformations are different only among capsule regions. Single-level anterior arthrodesis is associated with significantly less FJC deformation adjacent to the arthrodesis when the spine is in an extended orientation. 4.

Introduction CX3CL1 and its receptor (CX3CR1) are part of a chemokine system involved in leukocyte recruitment and adhesion in chronic inflammatory disease. From previous study, the CX3CL1 and CX3CR1 activity has been investigated in ligamentum flavum, synovial membrane, and intervertebral discs, but not with the facet joint capsule-related issue. The purpose of this study is to investigate the following: (1) The role of fractalkine (CX3CL1)/CX3CR1 chemokine on facet joint capsular laxity in degenerative lumbar spondylolisthesis (DLS); (2) Correlation between expression of CX3CL1/CX3CR1 chemokine and degree of slippage by lumbar spondylolisthesis. Method The mRNA concentrations of CX3CL1/CX3CR1 chemokine were analyzed in the surgically obtained facet joint capsule specimens from grade 1 spondylolisthesis ( n = 12), grade 2 spondylolisthesis ( n = 12), and more than grade 3 spondylolisthesis ( n = 11) by real-time PCR. Grade 1 to 3 is being decided on degree of slippage which is, less than 5 mm, between 5 to 10 mm, and more than 10 mm. The localization of CX3CL1/CX3CR1 chemokine within the facet joint capsule was determined using immunohistochemical study. Plasma level of soluble fractalkine (sFKN) was measured by enzyme-linked immunosorbent assay (ELISA), respectively. Result The cells that shows higher CX3CL1/CX3CR1 chemokine expression ratio in the facet joint capsule are observed in tissues acquired from patients with higher degree of slippage by lumbar spondylolisthesis ( p = 0.000, 0.000). In ELISA, the plasma levels of sFKN was significantly higher in the group with more severe degree of slippage ( p = 0.002). There was greater CX3CL1/CX3CR1 expression in higher grade spondylolisthesis as quantified by RT–PCR ( p = 0.000, 0.003). Degree of slippage in patients with DLS were significantly correlated with serum CX3CL1 level ( R2 = 0.451, p = 0.000) and with mRNA expression of CX3CL1/CX3CR1 ( R2 = 0.360, p = 0.000) ( R2 = 0.205, p = 0.006). Conclusion This study identified for the first time that increases in CX3CL1 and CX3CR1 expressing cells are significantly related to facet joint capsular laxity, which may provide new conceptual and therapeutic approaches for treating spinal spondylolisthesis.

Background: It has been proposed that cervical facet joint capsules are a major source of whiplash pain. However, there is a paucity of neurophysiologic data to support this hypothesis. The purposes of this study were to determine the distribution of A-δ and C-fiber sensory receptors in the facet joint capsule and to test their patterns of response to stretch and related sensory function. Methods: Laminectomy from C4 to C7 was performed in seventeen goats, while they were under general anesthesia, to expose the C6 nerve roots. Customized dual bipolar electrodes were used to record neural activity from one of the C6 branches. An 8 or 15-V electrical stimulus was used to provoke receptor activity in nine designated areas on the dorsal part of the C5-C6 facet joint capsule. Receptors were classified on the basis of conduction velocities. The waveform of an identified receptor was set up as a template to determine its neural activity in response to capsular stretch. The characteristics of each single receptor's response to capsular stretch were analyzed to determine its sensory function as a mechanoreceptor or nociceptor. Results: Two hundred and forty-eight receptors on the dorsal part of the C5-C6 facet joint capsule were evoked by electrical stimulation in the seventeen goats. More C-fiber receptors were found on the dorsolateral aspect of the facet joint capsule, where tendons and muscles were attached. The response to stretch of 120 receptors, from twelve goats, were analyzed to classify them into one of four categories (high-threshold mechanoreceptors, non-saturated low-threshold mechanoreceptors, saturated low-threshold mechanoreceptors, and silent receptors) or as unclassified receptors. Conclusions: The existence of receptors in the facet joint capsule indicates that the capsule has pain and proprioceptive sensory functions. Clinical Relevance: The cervical facet joint capsule may be a pain generator in whiplash-related disorders and chronic neck pain. On the basis of the assumption that human and goat facet-joint-capsule innervations are similar, it appears that treatment focusing on the dorsolateral aspect of the cervical facet joint may produce more effective outcomes by ablation of neural activity from nociceptors and the mechanoreceptors that are involved in pain.

To demonstrate the validity of placing electrodes parallel to the target nerve in lumbar radiofrequency neurotomy. Previous data on the anatomy of the lumbar dorsal rami were reviewed and a demonstration cadaver was prepared. Under direct vision, electrodes were placed on, and parallel to, the L4 medial branch and the L5 dorsal ramus. Photographs were taken to record the placement, and radiographs were taken to illustrate the orientation and location of the electrode in relation to bony landmarks. In order to lie in contact with, and parallel to, the target nerve, electrodes need to be inserted obliquely from below, so that their active tip crosses the neck of the superior articular process. At typical lumbar levels, the tip should lie opposite the middle two quarters of the superior articular process. At the L5 level, it should lie opposite the middle and posterior thirds of the S1 superior articular process. If electrodes are placed parallel to the target nerve, the lesions made can be expected to encompass the target nerves. If electrodes are placed perpendicular to the nerve, the nerve may escape coagulation, or be only partially coagulated. Placing the electrode parallel to the nerve has a demonstrated anatomical basis, and has been vindicated clinically. Other techniques lack such a basis, and have not been vindicated clinically. Suboptimal techniques may underlie suboptimal outcomes from lumbar medial branch neurotomy.

Diagnostic Medial Branch Blocks before Lumbar Radiofrequency Zygapophysial (Facet) Joint Denervation

The zygapophysial joints, together with the intervertebral disc, form a functional spine unit. The importance of the zygapophysial joints as a pain generator is often underestimated because the prevalence of zygapophysial joint pain (10–80 %) is difficult to specify. The prevalence increases with age, and it often comes along with other pain sources. Zygapophysial joints are typical synovial joints with a dual nerve supply from the medial branches of the dorsal rami. The joint capsule and the surrounding structures are richly innervated. The stretching of the capsule and loads being transmitted through the joint can cause pain. Degenerative changes are commonly found. Zygapophysial joints are often affected by osteoarthritis and inflammatory processes. Often additional factors including synovial cysts, spondylolisthesis, spinal canal stenosis, and injuries are present. Zygapophysial joint pain is a somatic referred pain. Morning stiffness and pain when moving from a sitting to a standing position are typical. No historic or physical examination variables exist to identify zygapophysial joint pain. Also, radiologic findings do not have a diagnostic value for zygapophysial joint pain. The most accepted method for diagnosing zygapophysial joint pain is controlled medial branch block. It is the most validated of all spinal interventions, although false-positive and false-negative results exist and the degree of pain relief after medial branch blocks remains contentious. The only truly validated treatment is radiofrequency neurotomy. The available techniques vindicate the use of medial branch neurotomy provided that the correct technique is used and patients are selected rigorously using controlled blocks.

Lumbar facet joints are a well recognized source of low back pain and referred pain in the lower extremity in patients with chronic low back pain. Conventional clinical features and other non-invasive diagnostic modalities are unreliable in diagnosing lumbar zygapophysial joint pain. Controlled diagnostic studies have shown the prevalence of lumbar facet joint pain in 27% to 40% of the patients with chronic low back pain without disc displacement or radiculitis, with a false-positive rate of 27% to 47% with a single diagnostic block. A systematic review of diagnostic and therapeutic lumbar facet joint interventions. To determine the clinical utility of diagnostic and therapeutic lumbar facet joint interventions in managing chronic low back pain of facet joint origin. Review of the literature for clinical studies on efficacy and utility of facet joint interventions in diagnosing and managing facet joint pain was performed according to the Agency for Healthcare Research and Quality (AHRQ) criteria for diagnostic studies and observational studies and the Cochrane Musculoskeletal Review Group criteria as utilized for interventional techniques for randomized trials. Data sources included relevant literature of the English language identified through searches of Medline and EMBASE from 1966 to December 2008 and manual searches of bibliographies of known primary and review articles. Analysis results were performed for diagnostic and therapeutic interventions separately. The level of evidence was defined as Level I, II, or III with 3 subcategories in Level II based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF) for therapeutic interventions. For diagnostic interventions, studies must have been performed utilizing controlled local anesthetic blocks. Pain relief was categorized as at least 80% pain relief from baseline pain and ability to perform previously painful movements. For therapeutic interventions, the primary outcome measure was pain relief with secondary outcome measures of improvement in functional status, psychological status, return to work, and reduction in opioid intake. For therapeutic interventions, short-term pain relief was defined as relief lasting 6 months or less and long-term relief as longer than 6 months. Based on USPSTF criteria, evidence showed Level I or II-1 for diagnostic facet joint nerve blocks. Based on the review of included therapeutic studies, Level II-1 to II-2 evidence was indicated for lumbar facet joint nerve blocks with indicated level of evidence of Level II-2 to II-3 for lumbar radiofrequency neurotomy. The shortcoming of this systematic review of lumbar facet joint interventions is the paucity of published literature. The evidence for diagnosis of lumbar facet joint pain with controlled local anesthetic blocks is Level I or II-1. The indicated level of evidence for therapeutic lumbar facet joint interventions is Level II-1 or II-2 for lumbar facet joint nerve blocks, Level II-2 or II-3 evidence for radiofrequency neurotomy, and Level III (limited) evidence for intraarticular injections.

Facet joint capsules (FJC) may experience large mechanical deformation under spine motion. There has been no previous quantitative study of the relationship between capsular strain and sensory nerve activation in spine FJC in vivo. Space limitation in the cervical spine makes such a study difficult, as the facet joint must be loaded while simultaneously monitoring nerve discharge from nerve roots immediately adjacent to the loaded tissue. A new methodology was developed to investigate biomechanical and neurophysiological properties of spine facet joint capsules in vivo. The method incorporated a custom-fabricated testing frame for facet joint loading, a stereoimaging system, and a template-matching technique to obtain single afferent response. It was tested by loading goat C5-C6 FJC in vivo with simultaneous nerve root recordings and 3D strain tracking of the capsules. Preliminary data showed that 18 of 23 afferents (78.3%) were found to be mechanosensitive to tensile stretch, and five were not responsive, even under tensile load as high as 27.5 N. Mechanosensitive afferents in goat capsules had tensile strain thresholds of 0.119+/-0.080. Neural responses of all mechanosensitive units showed statistically significant correlations (all P<<0.05) with both capsular load (r(2)=0.744+/-0.109) and local strain (r(2)=0.868+/-0.088). This method enables the investigation of the correlation between tissue load, deformation and neural responses of mechanoreceptors in spine facet joint capsules, and can be adapted to investigate tissue loading and neural response of other soft tissues.

Background: The trends of the expenditures of facet joint interventions have not been specifically assessed in the fee-for-service (FFS) Medicare population since 2009 Objectives: The objective of this investigation is to assess trends of expenditures and utilization of facet joint interventions in FFS Medicare population from 2009 to 2018. Study Design: The study was designed to analyze trends of expenditures and utilization of facet joint interventions in FFS Medicare population from 2009-2018 in the United States. In this manuscript: • A patient was considered as undergoing facet joint interventions throughout the year. • A visit included all regions treated during the visit. • An episode was considered as one per region utilizing primary codes only. • Services or procedures were considered all procedures (multiple levels). Data for the analysis was obtained from the standard 5% national sample of the Centers for Medicare &amp; Medicaid Services (CMS) physician outpatient billing claims for those enrolled in the FFS Medicare program from 2009 to 2018. All the expenditures were presented with allowed costs and also were inflation adjusted to 2018 US dollars. Results: This analysis showed expenditures increased by 79% from 2009 to 2018 in the form of total cost for facet joint interventions, at an annual rate of 6.7%. Cervical and lumbar radiofrequency neurotomy procedures increased 185% and 169%. However, inflation-adjusted expenditures with 2018 US dollars showed an overall increase of 53% with an annual increase of 4.9%. In addition, using inflation-adjusted expenditures per procedures increased, the overall 6% with an annual increase of 0.7%. Overall, per patient costs, with inflation adjustment, decreased from $1,925 to $1,785 with a decline of 7% and an annual decline of 0.8%. Allowed charges per visit also declined after inflation adjustment from $951.76 to $849.86 with an overall decline of 11% and an annual decline of 1.3%. Staged episodes of radiofrequency neurotomy were performed in 23.9% of patients and more than 2 episodes for radiofrequency neurotomy in 6.9%, in lumbar spine and 19.6% staged and 5.1% more than 2 episodes in cervical spine of patients in 2018. Limitations: This analysis is limited by inclusion of only the FFS Medicare population, without adding utilization patterns of Medicare Advantage plans, which constitutes almost 30% of the Medicare population. Conclusions: Even after adjusting for inflation, there was a significant increase for the expenditures of facet joint interventions with an overall 53% increase. Costs per patient and cost per visit declined. Inflation-adjusted cost per year declined 7% overall and 0.8% annually from $1,925 to $1,785, and inflation-adjusted cost per visit also declined 11% annually and 1.3% per year from $952 in 2009 to $850 in 2018. Key words: Facet joint interventions, facet joint nerve blocks, facet joint neurolysis, facet joint injections, Medicare expenditures

Dear Sir, During one of my efforts at peer reviewing an article on Bpulsed radiofrequency^ (PRF), I came upon a reference citation (previously published in Neuroradiology), which seemed to reflect an error. Direct exploration of the involved reference article, which was actually a letter to editor, and also the original article upon which the letter was directed, alerted me to a possible error in interpretation or understanding. Since the interpretation, and hence the resulting inference may naturally mislead others, I would like to clarify in the hopes of better informing readers. Masala et al. performed a prospective study on 92 patients with chronic low back pain, diagnosed as due to facet joint etiology, by controlled diagnostic, medial branch blocks [1]. The study’s main (true) objective was to evaluate the effectiveness of medial branch neurotomy performed by thermal radiofrequency (RF) in patients with facet joint syndrome, in decreasing pain and improving the quality of life. However, in their publication, they inserted the following sentences, which are misleading. In the first sentence of their abstract, they state: BThis study aimed to assess the effectiveness of pulsed radiofrequency medial branch dorsal ramus neurotomy in patients with facet joint syndrome^. Additionally, in the last sentence of their introduction, they also state: BThe purpose of this study is to evaluate the efficacy of the application of pulsed radiofrequency (RF) waves to medial branches of dorsal rami in the treatment of chronic facet joint pain^. Reading through the entire article, a physician familiar with the use of conventional, thermal radiofrequency neurotomy understands that the use of the term pulsed radiofrequency in the abstract, and in the introduction section is incorrect. Throughout the section on methodology, the investigators demonstrate that a thermal radiofrequency neurotomy was performed on the medial branches. The supporting sentences clearly indicate that the needles were placed in parallel to the respective medial branches by obtaining an ipsilateral oblique, slightly tunneled (caudad angle) view; after anaesthetising the area, thermoablation was completed by heating at 80 °C for 70 s. I am not entirely sure whether this mistake on the part of the main authors was due to a misunderstanding regarding the actual PRF application in pain interventions, or rather simply a use of incorrect terminology. In either case, this mistake was sufficient a generate a comment by Roy and Chatterjee which unfortunately leads to a further misinterpretation, or incorrect understanding of the main article [2]. Roy and Chatterjee question the use of pulsed RF by Masala et al.: Bwhat motivated the authors to opt for pulsed radiofrequency in facet pain cases is not clear^, and cite evidence to show that thermal RF is superior to pulsed RF. They further question the decision to omit a placebo group, by objecting to the proposed treatment (PRF) as a well-established technique in comparison to the thermal RF. Drs. Roy and Chatterjee were no doubt correct in their conceptualization and understanding of pulsed RF and thermal RF; however, it seems that they either did not read the methodology of the article they were commenting on, (perhaps misunderstood the methodology of the article they were commenting upon). Simply put, they could have just asked the authors not to use the term Bpulsed^, as it was evident otherwise. I would like to make one general observation, and another specific observation. As authors of a scientific paper, we have * Harsha Shanthanna shanthh@mcmaster.ca

Neurophysiological and biomechanical characterization of goat cervical facet joint capsules