
==== Front
Interv Pain Med
Interv Pain Med
Interventional Pain Medicine
2772-5944
Elsevier

S2772-5944(21)00009-1
10.1016/j.inpm.2021.100009
100009
Original Article
Lumbar medial branch block progression to radiofrequency neurotomy: A retrospective audit of clinical practice
Sherwood David david.sherwood@uhkc.org
a∗
Berlin Evan b
Gill Benjamin c
Epps Adam b
Gardner James b
Schneider Byron b
a Department of Orthopedics, University Health Lakewood Medical Center, Kansas City, MO, USA
b Department of Physical Medicine and Rehabilitation, Vanderbilt University Medical Center, Nashville, TN, USA
c Department of Physical Medicine and Rehabilitation, University of Missouri, Columbia, MO, USA
∗ Corresponding author. 7900 Lee's Summit Road, Kansas City, MO, 64139, USA. david.sherwood@uhkc.org
06 1 2022
3 2022
06 1 2022
1 1 10000918 10 2021
28 12 2021
29 12 2021
© 2021 The Author(s)
2021
https://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Introduction

Chronic axial low back pain due to zygapophysial joint arthropathy is best diagnosed via lumbar medial branch block (MBB). However, the paradigm by which MBB is used to select patients for lumbar radiofrequency neurotomy (RFN) is contested. Dual diagnostic lumbar MBB with a minimum of ≥80% pain relief to diagnose lumbar zygapophysial joint pain are accepted by some Medicare Local Coverage Determination (LCD) as the method for selecting patients for RFN for the management of lumbar zygapophysial joint pain. However, some argue that dual diagnostic MBB and the ≥80% pain relief threshold lack utility in clinical practice, given that those that progress from MBB1 to MBB2 will then flow from MBB2 to RFN without fail.

Study

Pragmatic retrospective clinical audit.

Objective

Does clinical practice of dual diagnostic lumbar MBBs and an ≥80% pain improvement diagnostic threshold reduce patient eligibility for RFN after both MBB1 and MBB2?

Results

Using dual diagnostic lumbar MBBs and an ≥80% pain improvement diagnostic threshold, 90/167 (54%, 95% CI 46–61%) patients successfully progressed from MBB1 to MBB2. Of those 90 patients, 66 patients (73%, 95% CI 64–82%) successfully progressed from MBB2 to RFN. Both MBB1 and MBB2 impacted the eligibility of the progression of 77/167 (46%, 95% CI 39–54%) patients and 24/90 patients (27%, 95% CI 18–36%), respectively. An additional sub-cohort analysis which included all the patients from the ≥80% pain relief cohort, and those who progressed at the discretion of the providers with 50–79% relief revealed that 124/167 patients (74%, 95% CI 68–81%) successfully progressed from MBB1 to MBB2. Of those 124 patients, 99 patients (80%, 95% CI 73–87%) progressed from MBB2 to RFN. In this laxer criteria cohort, MBB1 and MBB2 impacted the eligibility of the progression of 43/167 patients (26%, 95% CI 19–32%) and 25/124 patients (20%, 95% CI 13–27%), respectively.

Conclusion

MBB1 and MBB2 both filtered patients from progression to lumbar RFN using dual MBBs with an ≥80% pain relief criteria. It also held true when using a more relaxed pain relief selection criterion as well. Dual MBB's and ≥80% pain improvement criteria as a selection paradigm led to half as many lumbar RFNs being performed when compared to a single MBB and ≥80% pain improvement criteria. In theory, a more rigid selection paradigm treats less patients but exposes fewer to unnecessary RFNs while a laxer selection paradigm treats more patients but exposes more to unnecessary RFNs.

Keywords

Spine
Neurotomy
Ablation
Radiofrequency
Pain Management
Low Back Pain
Facet Joint
Z-joint
Zygapophysial Joint
Zygapophyseal joint
Chronic pain
Nonoperative
==== Body
pmc1 Introduction

Acute low back pain is common and has a favorable natural course [1,2]. However, chronic axial low back pain (CALBP), defined as pain greater than 3 months without the presence of radicular or myelopathic symptoms, is less common but among the most costly and debilitating diagnoses [[3], [4], [5], [6]]. There are many phenotypes of CALBP, which can be differentiated by thoughtful evaluation and intervention [[7], [8], [9], [10]]. Based on the cohort examined and criteria for selection, the zygapophysial joint, also known colloquially as the z-joint or facet joint, is implicated in 5–50% of CALBP cases [[11], [12], [13], [14], [15], [16], [17], [18], [19], [20]]. The most rigorous diagnostic selection methodology revealed a 15% prevalence [21]. Radiofrequency neurotomy (RFN) of the associated lumbar medial branches is a validated and efficacious intervention to treat this population [13,18,[22], [23], [24]]. No physical exam maneuvers, historical features, or imaging studies can independently diagnose CALBP of zygapophysial joint origin [13,17,25,26]. The diagnosis of zygapophysial joint pain is best achieved by medial branch block (MBB) [12,13,15,16,19,[26], [27], [28], [29], [30]]. [][12], [13], [15], [16], [19], [26], [27], [28], [29], [30][].

The paradigm through which MBB is used to diagnose zygapophysial joint pain is contested given the false positive rate for a single lumbar MBB is within the range of 15–45% [11,12,18,19,23,[25], [26], [27],[30], [31], [32]]. Some practitioners argue for a single MBB, some argue for dual MBBs, and some argue for a no MBB protocol for the diagnosis and treatment of CALBP of zygapophysial etiology. Moreover, there are differing opinions regarding which threshold of pain relief percentage denotes success with the MBB. The specifics of these debates are important but have been discussed previously and are beyond the scope of the present objective [15,23,25,27,29,30,[33], [34], [35]]. [][15], [23], [25], [27], [29], [30], [33], [34], [35][].

Dual MBBs with an 80% or greater pain relief cut off to diagnose zygapophysial joint pain have been accepted by the Spine Intervention Society (SIS) and some Medicare LCDs as the most appropriate method for diagnosing lumbar zygapophysial joint pain [36,37]. Some published consensus guidelines debate the merits of this selection criteria [30]. The argument against the dual block paradigm and the 80% or greater pain relief cut off is that a less stringent selection criteria may treat more patients and save healthcare dollars but potentially at the expense of more treatments upon patients that were false positives. Moreover, there are some who argue anecdotally that all patients who matriculate from the first MBB to the second MBB graduate to RFN, thus questioning the value of MBB2 in their practice setting.

The Spine Intervention Society endorses a dual block paradigm using an 80% or greater pain relief cut off given a preponderance of research demonstrating the highest positive outcome rates when patients are enrolled via this paradigm [36]. In 2020, Schneider et al. produced a systematic review which stratified qualifying data to demonstrate that using this patient selection paradigm, physicians may expect a 50–60% chance of patients achieving 50% relief, a 50% chance of achieving 80% relief, and a 25% chance of achieving complete relief along with improvements in function and decreased use of analgesics [23]. By advocating for these selection criteria, the Spine Intervention Society has made an endorsement towards “precision medicine” in the field of Interventional Pain Management.

The 2020 Multisociety International Working Group Consensus practice guidelines on lumbar facet joint pain recommend a single block using 50% or greater pain relief as the cut off [30]. Those consensus guidelines recognize that a no block paradigm likely benefits the most patients at the expense of treating some who may not benefit, while a dual block paradigm likely produces the highest rates of successful RFN outcomes but at the expense of withholding treatment for some who may benefit [30]. The consensus guidelines examined this statistical Rorschach test, and thus recommended a reasonable middle ground single block paradigm. The guidelines state that this decision allows physicians to practice “personalized medicine” tailored to their patient's needs, such that there exist contexts in which either a no block, single block, or dual block paradigm are most appropriate [30].

By not endorsing a dual block paradigm, it can be reasonably inferred that the authors of the consensus guidelines feel that the second medial branch block (MBB2) does not typically confer utility in clinical practice. Our research attempts to add further data to the conversation on the utility of MBB2 in clinical practice.

There have been prior seminal and valued studies which have assessed the significance of differing block paradigms as it relates to RFN outcomes, prognostic ability of differing pain-relief cut offs for RFN outcomes, and the financial cost of differing block paradigms [14,35,[41], [42], [43]]. Nested within those studies exist data, which is like our own, but importantly not identical. Our data is uniquely positioned as to address if prospective trial data regarding the utility of MBB1 and MBB2 to both prevent matriculation to RFN at some degree is manifested in clinical practice.

No prior studies have retrospectively audited clinical practice using the dual block paradigm and 80% or greater pain relief criteria to the dedicated assessment of whether this methodology reduce the number of patients who flow from MBB to RFN at both MBB1 and MBB2.

Our study is a retrospective review protocol study that set out to challenge this suspicion, does clinical practice using dual diagnostic lumbar MBBs and an 80% or greater pain relief reduce the number of patients who matriculate from MBB1 to MBB2 to RFN?

2 Methods

Institutional Review Board (IRB) approval was obtained. A database was retrospectively established with all recipients who underwent lumbar medial branch blocks based on Current Procedural Terminology (CPT) codes within a single department at a large academic institution between January 1st, 2019 and December 31st, 2019. Four fellowship-trained physiatrists performed all procedures in this study.

2.1 Procedural technique

The procedural technique for each provider noted in their associated procedure notes was consistent with the guidelines established by the Spine Intervention Society for MBB of the lumbar spine. [36] No patient was offered MBB1 before completing 4–6 weeks of conservative care. No patient received sedation. While data was not collected on local anesthetic usage, 2/4 of the physicians reviewed never use local anesthetic for this procedure while the remaining 2/4 physicians rarely use local anesthetic for this procedure. When local anesthetic was used, it was 2% lidocaine injected as a subdermal wheel using roughly 0.5 ​mL's. At the provider's discretion, 2% lidocaine or 0.5% bupivacaine were used for either MBB1 or MBB2. The same anesthetic was not used for both MBB1 and MBB2. No provider used steroids. No more than 0.5 ​cc per unilateral level was used. To reduce false negatives, contrast was always used before the anesthetic was injected to assess for vascular uptake and appropriate localization of the injectate.

2.2 Pain relief criteria

A minimum of 80% or greater pain relief determined a diagnostic MBB per our retrospective protocol. However, as this was a pragmatic retrospective review of clinical practice, each provider could matriculate patients with a ≥50% pain improvement threshold based on clinical judgement, as this was the insurance standard during the study time frame. Patients diagnosed via this method were identified separate from the studied cohort. Ultimately, the preferred tool for defining pain relief and thus matriculation to RFN was at the discretion of the provider. Those measurement tools included: (1) pre and post injection NRS or VAS data, (2) patient pain diaries of NRS and percentage relief scoring, and (3) post-injection follow-up visits where NRS or VAS scores were collected by patient recall.

2.3 Inclusion and exclusion criteria

2.3.1 Inclusion criteria

1. First lumbar medial branch block was performed between January 1st, 2019 and December 31st, 2019.

2. The procedure only targeted the lumbar medial branches or the L5 dorsal ramus.

2.3.2 Exclusion criteria

1. Patients received a lumbar medial branch block or neurotomy before January 1st, 2019 to the same level and laterality.

2. The procedure targeted either the cervical or thoracic medial branches, or the sacral lateral branches.

3. The patient did not undergo medial branch block, rather a procedure with the same CPT code (e.g., facet injection or costovertebral joint injection)

The medical records of patients selected with the above criteria were individually reviewed by a team of five physicians. The researchers collected data on the patient's demographics (i.e., age, sex), duration of pain, target nerve levels, pre-procedure pain, post-procedure pain, pain relief duration of the MBBs, if patient proceeded to the second MBB, the rationale for failure to matriculate if documented, and if the patient proceeded to RFN.

If the patient did not follow-up after the first or second medial branch block, regardless of immediate post-procedure pain score, it was considered a failure to matriculate. All data were stored in password-secured documents. Data shared between researchers was sent via encrypted emails with no patient identifiable information, in accordance with the Health Insurance Portability and Privacy Act.

3 Results

A total of 167 patients underwent lumbar MBB and fulfilled the inclusion and exclusion criteria. The mean duration of pain was 49.3 months. The mean numeric rating score (NRS) pre-MBB1 was 6.0. The mean NRS pre-MBB2 was 5.3. The mean time between MBB1 and MBB2 was 26 days. There were 54 unilateral and 113 bilateral patients. The L1-2, 2–3 joints were targeted in 6 patients (3.6%), the L2-3 joint was targeted in 2 patients (1.2%), the L2-3, L3-4 joints were targeted in 6 patients (3.6%), the L2-3, L3-4, L4-5 joints were targeted in 3 patients (1.8%), the L3-4 joint was targeted in 4 patients (2.4%), and the L4-5, 5–1 joints were targeted in the remaining 146 patients (87.4%). Aside from insufficient improvement in reported pain, other reasons were identified in the medical records for lack of progression to RFN. See Table 1.Table 1 List of alternative reasons collected for lack of progression.

Table 1Reason	MBB1	MBB2	
Declined Further Treatment	1	2	
Lost to Follow Up	2	4	
Sustained Pain Relief	3	2	
Excessive Discomfort	1	0	
Insurance Denial	0	1	

3.1 ≥ ​80% pain relief in both MBB1 and MBB2 cohort

Based on a threshold of 80% pain improvement, 90/167 patients (54%, 95% CI 46–61%) progressed from MBB1 to MBB2 after ≥80% pain improvement. Of those 90 patients, 66 patients (73%, 95% CI 64–82%) also progressed from MBB2 to RFN. Ultimately, 66/167 (40%, 95% CI 32–47%) patients who were initially suspected to have zygapophysial joint pain progressed to RFN. The application of the ≥80% relief screening threshold in both MBB1 and MBB2 impacted the RFN eligibility of 77/167 patients (46%, 95% CI 39–54%) and 24/90 patients (27%, 95% CI 18–36%), respectively. See Fig. 1.Fig. 1 Flow of patients from the first medial branch block to the second medial branch block to radiofrequency neurotomy in the ≥80% pain relief cohort.

Fig. 1

3.2 Clinical practice, ≥50% pain relief in both MBB1 and MBB2 cohort

This cohort includes all the patients from the ≥80% pain relief in both MBB1 and MBB2 cohort, and those who progressed at the discretion of the providers with 50–79% relief. In total, 124/167 patients (74%, 95% CI 68–81%) successfully progressed from MBB1 to MBB2. Of those 124 patients, 99 patients (80%, 95% CI 73–87%) progressed from MBB2 to RFN. Ultimately, 99/167 patients (59%, 95% CI 52–67%) who were initially suspected to have potential CALBP due to zygapophysial joint pain progressed to RFN. In our clinical practice audit, MBB1 and MBB2 impacted the eligibility of the progression of 43/167 patients (26%, 95% CI 19–32%) and 25/124 patients (20%, 95% CI 13–27%), respectively. See Fig. 2.Fig. 2 Flow of patients from the first medial branch block to the second medial branch block to radiofrequency neurotomy in the clinical practice cohort.

Fig. 2

Of note, 9/167 (5%, 95% CI 2–9%) patients had ≥80% pain relief after MBB1 but 50%–79% pain relief after MBB2 yet still advanced to RFN. Similarly, 15/167 (9%, 95% CI 5–13%) patients had 50%–79% pain relief after MBB1 and ≥80% pain relief after MBB2 yet still advanced to RFN.

4 Discussion

In this retrospective review from January 1st, 2019, to December 31st, 2019, of practice habits reflective of SIS and some Medicare LCD guidelines of dual diagnostic lumbar MBBs with an ≥80% pain relief criteria, both MBB1 and MBB2 served to filter patients from progression to RFN. Moreover, this held true using either ≥80% pain relief or the less rigorous clinical practice cohort. In both selection habits, patients were filtered from RFN progression at both MBB1 and MBB2.

Chronic axial low back pain is admittedly challenging to treat. Despite improved diagnostic specificity to individual pathologies, there remains a lack of robustly validated interventions to manage each concern [7,8,[38], [39],40]. Inconsistent efficacy with interventions is at least partially due to differing patient selection methods and subsequent heterogeneous data sets. As demonstrated in broad analysis, outcomes for RFN tend to worsen with less selective criteria [23]. Enhanced identification of successful interventions will perhaps occur with consistent and prolonged application of dual diagnostic MBB with an ≥80% pain relief threshold. Furthermore, use of single-institution registries and large insurance-based datasets may also be leveraged to assess pragmatic outcomes of procedures such as RFN. Clinical over-utilization of this procedure in patients without lumbar zygapophyseal pain carries a theoretical risk of poorer outcomes, which may ultimately restrict access of the procedure to the entire population.

The lack of RFN outcome data is addressed in Limitations. However, despite no RFN outcome data, some inferences may be made. If our practice had utilized a single block paradigm and 50% pain relief cut off as endorsed by the Multisociety Consensus Practice Guidelines, 124 RFN's would have been carried out compared to the 66 using the dual block paradigm and 80% pain relief cut off as endorsed by the Spine Intervention Society [30,36]. In our clinical audit, the Consensus guidelines exposed an additional 66 patients to RFN, or a 200% increase over the SIS endorsed guidelines.

Our research perhaps corroborates that using a dual block paradigm and 80% or greater pain relief cutoff in the clinical setting is needed to replicate the patient selection in research which shows the highest RFN outcomes. Moreover, by relaxing that rigor, we should expect outcome rates to worsen, yet we may treat more patients. Cohen et al. (2010) masterfully compared multiple selection paradigms to demonstrate that a dual block paradigm was the most precise when selecting patients for successful RFN, albeit at the expense of those who were filtered out by either block who may have benefited [35]. While our study did not aim to replicate that of Cohen, our study did pragmatically evaluate the utilization of RFN in clinical practice when a two-block paradigm is used, 66 RFNs, and be extension how many RFNs would have occurred if only a single block paradigm and 50% pain relief cutoff had been applied, 124 RFNs [30].

4.1 Clinical practice, ≥50% pain relief in both MBB1 and MBB2 cohort

The physicians involved in this study practice at a large, research-oriented academic institution. Overall, a firm criterion of ≥80% reported pain improvement was favored for progression to RFN. However, some patients progressed with greater than 50% relief but without fulfilling the selection criteria currently endorsed by SIS and some Medicare LCD guidelines. Specifically, 34/167 (20%, 95% CI 14–26%) advanced from MBB1 to MBB2 and 33/124 (27%, 95% CI 19–34%) advanced from MBB2 to RFN without demonstrating 80% relief at MBB1 and/or MBB2.

In 2010, Cohen et al. reported using a dual block ≥50% pain relief criterion to demonstrate 29/50 (58%) progression from MBB1 to MBB2, and 14/26 (54%) progression from MBB2 to RFN [35]. In our study, 124/167 (74%) progressed from MBB1 to MBB2 and 99/124 patients (80%) progressed from MBB2 to RFN when using a dual block ≥50% pain relief criterion. These differences may be explained by differing patient populations and differing patient selection for both the procedure itself and advancement.

In this cohort, there was a common scenario in which a patient's pain scores would reduce from a 7 to a 2, or a 4 to a 1. In both scenarios, a passive observer might deem these results successful. However, by use of the ≥80% pain relief criteria, both the 7 to 2 and 4 to a 1 patient's would not have been deemed successful enough to further matriculate to the next stage as their pain relief is statistically 71% and 75%, respectively. Moreover, certain patients had a MBB carried out with the expressed understanding that complete pain relief was not a realistic expectation given underlying medical comorbidities which provided an inherent level of pain or alternative spinal pain generators which may not have been amenable to treatment. Thus, in these patients the ≥80% pain relief criteria were felt to be an unfair hurdle to define success.

In this practice of physicians, the clinical decision to progress when the results were between 50 and 79% resulted in some additional procedures but were not universally grounds for progression. We would argue that by allowing physicians leeway with regards to less rigid matriculation such that they may use clinical judgement to assess RFN success potential would remedy both the previously discussed issues we encountered. By allowing physicians to exercise their judgement of the patients in front of them, then perhaps the previously described incidents which might restrict care could be limited.

4.2 Limitations

Several limitations were identified within the course of this study. Regarding heterogeneity, the charts reviewed reflect the practice habits of four interventionalists. The ultimate selection criteria for medial branch block candidacy were at the discretion of each provider. Furthermore, the methods of pain threshold determination and reporting were non-standardized between physicians. Therefore, any associated findings lack generalizability given presumed differences in patient selection or referral patterns.

As noted above, there are many reasons why a patient may not matriculate to RFN after MBB. While primarily due to inadequate pain relief based on diagnostic protocols, the figures in this study do not accommodate other reasons for cessation of progression. The lack of discrimination introduces a “best case” analysis bias in favor of the dual block paradigm. However, the aim of this analysis was an overall audit of clinical practice regarding the use of staged blocks as diagnostic filters rather than an elaboration of factors preventing RFN.

Many readers may seek outcome data related to these procedures. However, due to a lack of consistent post-RFN follow-up and data collection, outcome data would be potentially unreliable and misleading. Ultimately, this study was not designed to evaluate the outcomes of RFN.

5 Conclusion

This retrospective review of the practice habits of four spine providers at large tertiary academic spine center demonstrated filtration of patient progression to RFN from both MBB1 and MBB2 with use of ≥80% pain improvement criteria. The ≥80% threshold impacted RFN eligibility of 77/167 patients (46%, 95% CI 39–54%) following MBB1, and 24/90 patients (27%, 95% CI 18–36%) following MBB2. Impaired matriculation was also seen with less rigorous selection criteria. Dual MBB's and ≥80% pain improvement criteria as a selection paradigm led to half as many lumbar RFNs being performed when compared to a single MBB and ≥80% pain improvement criteria. In theory, a more rigid selection paradigm treats less patients but exposes fewer to unnecessary RFNs while a laxer selection paradigm treats more patients but exposes more to unnecessary RFNs.

Conflicts of interest

The authors declare no conflicts of interest.

Funding

The authors have no sources of funding to declare for this manuscript.
==== Refs
References

1 Dillane J.B. Fry J. Kalton G. Acute back syndrome—a study from general practice Br Med J 2 5505 1966 82 84 20791052
2 Vasseljen O. Woodhouse A. Bjrngaard J.H. Leivseth L. Natural course of acute neck and low back pain in the general population: the HUNT study Pain 154 8 2013 1237 1244 10.1016/j.pain.2013.03.032 23664654
3 Woolf A.D. Pfleger B. Burden of major musculoskeletal conditions Bull World Health Organ 81 9 2003 646 656 14710506
4 Carragee EJ. Persistent low back pain. https://doi.org/10.1056/NEJMcp.042054. doi:10.1056/NEJMcp042054.
5 Hart L.G. Deyo R.A. Cherkin D.C. Physician office visits for low back pain. Frequency, clinical evaluation, and treatment patterns from a U.S. national survey Spine 20 1 1995 11 19 10.1097/00007632-199501000-00003 7709270
6 Juch J.N.S. Maas E.T. Ostelo R.W.J.G. Effect of radiofrequency denervation on pain intensity among patients with chronic low back pain JAMA 318 1 2017 68 81 10.1001/jama.2017.7918 28672319
7 DePalma M.J. Diagnostic nihilism toward low back pain: what once was accepted, should No longer Be Pain Med Malden Mass 16 8 2015 1453 1454 10.1111/pme.12850
8 DePalma M.J. Ketchum J.M. Saullo T.R. Multivariable analyses of the relationships between age, gender, and body mass index and the source of chronic low back pain Pain Med Malden Mass 13 4 2012 498 506 10.1111/j.1526-4637.2012.01339.x
9 DePalma M.J. Ketchum J.M. Saullo T.R. Etiology of chronic low back pain in patients having undergone lumbar fusion Pain Med Malden Mass 12 5 2011 732 739 10.1111/j.1526-4637.2011.01098.x
10 DePalma M. Ketchum J. Saullo T. Schofferman J. Structural etiology of chronic low back pain due to motor vehicle collision Pain Med Malden Mass 12 11 2011 1622 1627 10.1111/j.1526-4637.2011.01246.x
11 Cohen S.P. Larkin T.M. Chang A.S. Stojanovic M.P. The causes of false-positive medial branch (facet joint) blocks in soldiers and retirees Mil Med 169 10 2004 781 786 10.7205/MILMED.169.10.781 15532341
12 Manchukonda R. Manchikanti K.N. Cash K.A. Pampati V. Manchikanti L. Facet joint pain in chronic spinal pain: an evaluation of prevalence and false-positive rate of diagnostic blocks Clin Spine Surg 20 7 2007 539 545 10.1097/BSD.0b013e3180577812
13 Bogduk N. Evidence-informed management of chronic low back pain with facet injections and radiofrequency neurotomy Spine J 8 1 2008 56 64 10.1016/j.spinee.2007.10.010 18164454
14 Cohen S.P. Stojanovic M.P. Crooks M. Lumbar zygapophyseal (facet) joint radiofrequency denervation success as a function of pain relief during diagnostic medial branch blocks: a multicenter analysis Spine J 8 3 2008 498 504 10.1016/j.spinee.2007.04.022 17662665
15 Van Zundert J. Mekhail N. Vanelderen P. van Kleef M. Diagnostic medial branch blocks before lumbar radiofrequency zygapophyseal (facet) joint denervation: benefit or burden? Anesthesiology 113 2 2010 276 278 10.1097/ALN.0b013e3181e33b02 20571358
16 Schwarzer A.C. Derby R. Aprill C.N. Fortin J. Kine G. Bogduk N. Pain from the lumbar zygapophyseal joints: a test of two models Clin Spine Surg 7 4 1994 331 336
17 Manchikanti L. Singh V. Pampati V. Are diagnostic lumbar medial branch blocks valid? Results of 2-year follow-up Pain Physician 6 2 2003 147 153 16883373
18 Dreyfuss P. Halbrook B. Pauza K. Joshi A. McLarty J. Bogduk N. Efficacy and validity of radiofrequency neurotomy for chronic lumbar zygapophyseal joint pain Spine 25 10 2000 1270 1277 10806505
19 Rocha ID da Cristante A.F. Marcon R.M. Controlled medial branch anesthetic block in the diagnosis of chronic lumbar facet joint pain: the value of a three-month follow-up Clinics 69 8 2014 529 534 10.6061/clinics/2014(08)05 25141111
20 Wahezi S.E. Alexeev E. Georgy J.S. Lumbar medial branch block volume-dependent dispersion patterns as a predictor for ablation success: a cadaveric study PM&R 10 6 2018 616 622 10.1016/j.pmrj.2017.11.011 29174073
21 MacVicar J. MacVicar A.M. Bogduk N. The prevalence of “pure” lumbar zygapophyseal joint pain in patients with chronic low back pain Pain Med Malden Mass 22 1 2021 41 48 10.1093/pm/pnaa383
22 Conger A. Burnham T. Salazar F. The effectiveness of radiofrequency ablation of medial branch nerves for chronic lumbar facet joint syndrome in patients selected by guideline-concordant dual comparative medial branch blocks Pain Med 21 5 2020 902 909 10.1093/pm/pnz248 31609391
23 Schneider B.J. Doan L. Maes M.K. Systematic review of the effectiveness of lumbar medial branch thermal radiofrequency neurotomy, stratified for diagnostic methods and procedural technique Pain Med 21 6 2020 1122 1141 10.1093/pm/pnz349 32040149
24 MacVicar J. Borowczyk J.M. MacVicar A.M. Loughnan B.M. Bogduk N. Lumbar medial branch radiofrequency neurotomy in New Zealand Pain Med Malden Mass 14 5 2013 639 645 10.1111/pme.12000
25 Engel A.J. Bogduk N. Mathematical validation and credibility of diagnostic blocks for spinal pain Pain Med Malden Mass 17 10 2016 1821 1828 10.1093/pm/pnw020
26 Manchikanti L. Pampati V. Fellows B. Bakhit C.E. The diagnostic validity and therapeutic value of lumbar facet joint nerve blocks with or without adjuvant agents Curr Rev Pain 4 5 2000 337 344 10.1007/s11916-000-0016-4 10998741
27 Bogduk N. Diagnostic nerve blocks in chronic pain Best Pract Res Clin Anaesthesiol 16 4 2002 565 578 10.1053/bean.2002.0252 12516892
28 Sehgal N. Dunbar E.E. Shah R.V. Colson J. Systematic review of diagnostic utility of facet (zygapophyseal) joint injections in chronic spinal pain: an update Pain Physician 10 1 2007 213 228 17256031
29 Bogduk N. Dreyfuss P. Govind J. A narrative review of lumbar medial branch neurotomy for the treatment of back pain Pain Med 10 6 2009 1035 1045 10.1111/j.1526-4637.2009.00692.x 19694977
30 Cohen S.P. Bhaskar A. Bhatia A. Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group Reg Anesth Pain Med April 3, 2020 10.1136/rapm-2019-101243 Published online
31 Schwarzer A.C. Aprill C.N. Derby R. Fortin J. Kine G. Bogduk N. The false-positive rate of uncontrolled diagnostic blocks of the lumbar zygapophyseal joints Pain 58 2 1994 195 200 10.1016/0304-3959(94)90199-6 7816487
32 Bogduk N. On diagnostic blocks for lumbar zygapophyseal joint pain F1000 Med Rep 2010 2 10.3410/M2-57 20948866
33 Derby R. Melnik I. Lee J.-E. Lee S.-H. Correlation of lumbar medial branch neurotomy results with diagnostic medial branch block cutoff values to optimize therapeutic outcome Pain Med 13 12 2012 1533 1546 10.1111/j.1526-4637.2012.01500.x 23126379
34 Cohen S.P. Strassels S.A. Kurihara C. Establishing an optimal “cutoff” threshold for diagnostic lumbar facet blocks: a prospective correlational study Clin J Pain 29 5 2013 382 391 10.1097/AJP.0b013e31825f53bf 23023310
35 Cohen S.P. Williams K.A. Kurihara C. Multicenter, randomized, comparative cost-effectiveness study comparing 0, 1, and 2 diagnostic medial branch (facet joint nerve) block treatment paradigms before lumbar facet radiofrequency denervation Anesthesiology 113 2 2010 395 405 10.1097/ALN.0b013e3181e33ae5 20613471
36 Practice Guidelines Spine intervention society https://www.spineintervention.org/general/custom.asp?page=Guidelines
37 Local Coverage Determination for Facet Joint Injections Medial branch blocks, and facet joint radiofrequency neurotomy (L34832) https://www.cms.gov/medicare-coverage-database/details/lcd-details.aspx?LCDId=34832&ver=18&CoverageSelection=Both&ArticleType=All&PolicyType=Final&s=All&KeyWord=facet+joint+injection&KeyWordLookUp=Title&KeyWordSearchType=And&bc=gAAAAAgAAAAA&
38 Dreyfuss P. Schwarzer A.C. Lau P. Bogduk N. Specificity of lumbar medial branch and L5 dorsal ramus blocks: a computed tomography study Spine 22 8 1997 895 902 9127924
39 DePalma M.J. Ketchum J.M. Saullo T. What is the source of chronic low back pain and does age play a role? Pain Med Malden Mass 12 2 2011 224 233 10.1111/j.1526-4637.2010.01045.x
40 Levin J.H. Prospective, double-blind, randomized placebo-controlled trials in interventional spine: what the highest quality literature tells us Spine J Off J North Am Spine Soc. 9 8 2009 690 703 10.1016/j.spinee.2008.06.447
41 Nath S. Nath C.A. Pettersson K. Percutaneous lumbar zygapophysial (Facet) joint neurotomy using radiofrequency current, in the management of chronic low back pain: a randomized double-blind trial discussion 1298 Spine (Phila Pa 1976) 33 12 2008 May 20 1291 1297 10.1097/BRS.0b013e31817329f0 PMID: 18496338 18496338
42 Derby Richard Melnik Irina Lee Jeong-Eun Lee Sang-Heon Cost comparisons of various diagnostic medial branch block protocols and medial branch neurotomy in a private practice setting Pain Med 14 3 March 2013 378 391 10.1111/pme.12026 23294522
43 Derby R. Melnik I. Lee J.E. Lee S.H. Correlation of lumbar medial branch neurotomy results with diagnostic medial branch block cutoff values to optimize therapeutic outcome Pain Med 13 12 2012 Dec 1533 1546 10.1111/j.1526-4637.2012.01500.x Epub 2012 Nov 5. PMID: 23126379 23126379
