The Source and the Course of the Articular Branches to the T4-T8 Zygapophysial Joints

The effectiveness of thoracic medial branch radiofrequency neurotomy using a three-tined electrode: A single-arm, retrospective cohort study

Background

Thoracic medial branch radiofrequency neurotomy (TMBRFN) is used to treat chronic thoracic facet joint pain, but research on its technique and effectiveness is still needed. The current International Pain and Spine Intervention Society Practice Guidelines do not describe a technique for TMBRFN.

Objectives

Evaluate the effectiveness of TMBRFN in patients with thoracic facet joint pain.

Methods

Single-arm, retrospective cohort study of consecutive patients from two Canadian musculoskeletal pain management clinics who underwent first-time TMBRFN between 2016 and 2022. The primary outcome was the proportion of patients with ≥50 % reduction in numerical rating scale (NRS) pain score at 3-months post-procedure. Secondary outcomes included the proportion of patients who achieved a ≥17-point reduction on the Pain Disability Quality-Of-Life Questionnaire-Spine (PDQQ-S) at 3-months, as well as mean patient-reported percentage pain relief and duration of relief after a successful index TMBRFN in individuals who reported a return of their index symptoms.

Results

18 consecutive patients (50.0 % male; mean age 60.9 ± 15.3 years; mean BMI 30.3 ± 6.9 kg/m2) were analyzed. At 3 months post-procedure, 10 patients (55.6 % [95%CI 33.7-75.4]) reported ≥50 % NRS pain reduction and 9 (50.0 % [95%CI 29.0-71.0]) reported ≥17-point PDQQ-S reduction. Of the 10 patients with successful treatment responses, 4 had a return of symptoms after an average of 9.3 ± 2.2 months with a reported retrospective mean percentage pain relief of 70.0 ± 34.6 %.

Conclusion

Within this cohort, approximately 60 % of patients experienced improvement in pain and disability at 3 months following TMBRFN. Among patients whose index symptoms returned after successful treatment, the average reported pain relief was 70 % for close to 9 months. Larger, prospective studies with long-term outcomes are needed to better elucidate the safety and effectiveness of TMBRFN.

Investigation of the anatomical course of articular branches to the thoracic zygapophysial joints

Background

Recent studies have questioned the validity of targeting the thoracic medial branch via anesthetic blocks or radiofrequency neurotomy for the diagnosis or treatment of pain from the thoracic zygapophysial joints.

Purpose

To define the origin and course of the articular branches to the thoracic zygapophysial joints at all levels.

Design

Cadaveric dissection.

Setting

The Gross Anatomy Laboratory at the University of New England College of Osteopathic Medicine.

Subjects

One cadaveric thoracic spine.

Methods

Gross and stereoscopic dissection of the bilateral dorsal rami T1-T12 was performed on one embalmed cadaver. The medial and lateral branches were traced from their cutaneous distribution to the origin at the dorsal ramus. The articular branches were identified using stereoscopic dissection by tracing their origin from the dorsal ramus or medial branch to the capsule of the zygapophysial joint. The images were recorded using digital photography.

Results

Twenty-two of the twenty-four articular branches were identified in a single cadaveric specimen. Articular branches at T7 on the right side and T9 on the left side were not identified. 5 of the 22 (18%) articular branches were observed to arise from the proximal segment of the medial branch of the dorsal ramus. Of the remainder, 17 of the 22 (78%) articular branches were observed to arise from the dorsal primary ramus itself. At levels T1-9, the articular branch coursed inferiorly along the lamina to reach the joint capsule. At levels T10-T12, the articular branch traversed the intervertebral foramen to reach the facet joint. The T12 medial branch on the left was seen to travel inferior to innervate the L1/L2 zygapophysial joint.

Conclusion

The source of the innervation for the thoracic zygapophysial is variable and can arise from the dorsal ramus itself or from the proximal segment of the medial branch. Unlike the cervical and lumbar medial branches, which innervate two joints each, in this case, the thoracic dorsal rami appear to innervate only the zygapophysial joint at the level of the nerve exit. It should be noted that the findings may be limited in their generalizability due to the reliance on a single cadaver study.

Comparison of two needle versus one needle lesioning techniques for thoracic medial branch neurotomy

Background and objectives

No prior studies have investigated an assumed advantage of creating a radiofrequency strip lesion for posterior element spinal axial pain using a two-needle technique (TNT) compared to a one-needle technique (ONT) that creates a single ovoid lesion. We explore the relationship of TNT compared to ONT on the magnitude and duration of pain relief following thoracic medial branch neurotomy (TMBN).

Methods

This study is a retrospective audit of consecutive patients treated with TMBN at a single site and interventionalist over ten years (2007-2017). All patients had undergone TMBN after failed conservative care and, with few exceptions, patient-reported ≥ 70% pain relief after thoracic medial branch block (TMBB). All patients had TMBN performed with a medial to lateral (MLA) radiofrequency cannula approach using either an ONT or TNT technique. We used parametric and nonparametric statistics and three levels of case analysis to assess for intergroup differences.

Results

Thirty-five consecutive patients underwent their primary TMBN, and two underwent both on a subsequent repeat using the MLA approach, 19 using the ONT, 18 using the TNT. The TNT group had clinically and statistically greater pain relief magnitude and duration than the ONT subgroup. The difference resulted in non-overlapping 95% confidence intervals for both percent pain relief and duration of pain relief using three levels of case analysis.

Conclusion

The comparison of TMBN techniques demonstrates a statistically significant separation of TNT to ONT sample mean values for magnitude and duration of pain relief when using TNT compared to ONT for TMBN using an MLA.

A proposed nomenclature for spinal imaging and interventional procedural reporting

Objective

To develop precise universal standard interventional spine nomenclature for reporting procedural details and anatomy.

Methods

There is no comprehensive nomenclature of spinal imaging anatomy that can be used for anatomical and procedural reporting. Given this critical lack of unifying terminology, a system of nomenclature was developed de novo by expert consensus, based upon clinical needs, and previously published reports.

Results

Nomenclature for anatomical and spine procedural reporting for interlaminar and transforaminal approaches was developed using zones in each view. Separate nomenclature for medial branch procedural reporting and discs and vertebral body location and procedural reporting is also presented.

Conclusion

There is a need for a unified anatomical location reporting system in interventional spine. The first step is the development of a precise, simple, and intuitive nomenclature, as reported here. The second is ratification followed by dissemination and adoption in clinical practice.

Combined thoracic medial branch radiofrequency and chemical neurotomy

Objective

Explore the effectiveness of thoracic medial branch neurotomy (MBN) using combined radiofrequency neurotomy and neurolytic lesioning.

Design

A retrospective cohort of consecutive patients with chronic thoracic axial pain treated in a community setting.

Interventions

We included all patients who underwent MBN between 2010 and 2016, selected for MBN primarily based on 70% relief following single or dual diagnostic medial branch blocks. Using 18-gauge cannulas, we placed electrodes and made lesions at the suspected location of the thoracic medial branch based on anatomic knowledge at the time; the thermal lesions were supplemented with 50% dextrose to enhance the lesion radius.

Measures

We defined success as ≥50% relief of their index thoracic pain not returning to baseline for at least six months. Patients not reached for follow-up were considered failures for worst-case analysis.

Results

Twenty-eight patients underwent an initial MBN between 2010 and 2016: Twenty-five of twenty-eight (89%) patients reported ≥70% pain reduction not returning to baseline for six months or longer. Using a worst-case analysis (WCA), patients reported average pain relief of 73% CI (63%,84%) with a mean duration of relief following the initial MBN of 9.9 months CI (6, 13.5). Seventeen of the initial 28 patients had a total of 31 repeat MBNs, 13/17 (76%) having pain relief reinstated after one or more repeat MBNs with an average duration of relief following a first repeat MBNs of 10.9 months CI (6.6,15.2).

Conclusion

Thoracic MBN combined with a mild neurolytic is a potentially effective treatment for thoracic pain in patients selected with positive diagnostic MBB. There were no complications noted. One can reinstate pain relief with repeated MBN in most patients should their symptoms return.