Medial Branch Research Articles

Generation and Editing of 2D Shapes using a Branched Representation

In this paper we propose a new planar shape representation, the medial branch graph representation (MBGR) which allows to easily generate, vary and edit all-new sorts of parametric shapes. Each MBGR shape is described by a collection of connected control circles organized as a graph. Each pair of connected circles generates a branch of the shape. The boundaries of the branches are designed using cubic Bézier curves which enable shape representation in a compact SVG format. Each circle is associated with a regularity parameter locally controlling the smoothness of the branch connections. In this way, we can manage shapes having both sharp corners and smooth boundaries. To illustrate the potential of the MBGR representation we have created an online facility ( https://mbgrg.github.io/mbgrg/ ) where the user can create/edit MBGR shapes automatically or interactively.

Targeted Muscle Reinnervation in the Upper Arm: A Functional Anatomical Study

BackgroundThe aim of this study was to accurately locate the neural fascicle controlling hand movement in the upper arm, to enhance expression of motor intention after targeted muscle reinnervation. MethodsThe right sides of the median, ulnar and radial nerves were dissected from distal to proximal in 6 fresh cadaver specimens. The sectional location and diameter of the functional fascicle were measured at 10 and 20 cm below the acromion. The diameter of the main muscle branches of muscle reinnervation target muscles was measured. ResultsThe median nerve branch of finger and wrist flexion was mainly located between the 9 and 12 o’clock positions in the plane 10 and 20 cm below the acromion, where the diameter of the nerve fascicle was 2.07 and 2.04 mm, respectively. The ulnar nerve branch of finger and wrist flexion was mainly located between the 8 and 12 o’clock positions, with a diameter of respectively 1.80 and 1.99 mm. The radial branch of finger and wrist extension was mainly located between the 10 and 2 o’clock positions in the plane 10 cm below the acromion and between 6 and 12 o’clock in the plane 20 cm below the acromion, with a diameter of respectively 2.57 and 3.03 mm. ConclusionsThe nerve fascicles innervating the flexor and extensor fingers were distributed in relatively constant regions of the median, ulnar and radial nerve trunks, and their diameters closely matched the muscle branches of the target muscle.

An unilateral double fenestration of the right external jugular vein: a rare variant.

This report presents a rare anatomical variation, double fenestration of the External jugular vein on the right side. During the routine dissection of a male cadaver aged 60 years, we observed a unilateral large double fenestration of the External jugular vein on the right side. After its formation from the posterior division of the retromandibular and posterior auricular veins, External jugular vein descended in the posterior triangle of neck. Here, it divided into medial, intermediate, and lateral veins that united again before draining into the subclavian vein. Lateral vein was the largest (7.2cm) and intermediate and medial veins were measuring 6.4cm each. Two large fenestrations, measuring 5.8cm each, arranged like a "double bubble" were seen in the External jugular vein extending from fourth to sixth cervical (C4 to C6) vertebrae. The medial branch of supraclavicular nerve was seen passing superficial to the distal part of External jugular vein. On the left side, the course of External jugular vein showed a standard pattern. Surgeons must be acquainted with the varied anatomy of the superficial neck veins to prevent major bleeding during operative procedures, including carotid endarterectomy, flap operations, & central venous catheterisation.

Optimal caudal needle angulation for lumbar medial branch denervation: A 3D cadaveric and clinical imaging comparison study

BackgroundLumbar medial branch (MB) radiofrequency ablation is a common intervention to treat facetogenic low back pain. The consensus among spine pain interventionalists is that capturing a greater length of the MB correlates with a longer duration of pain relief. Therefore, there has been interest in defining optimal needle angles to achieve parallel cannula placement. Presently, there is inconsistency regarding the optimal caudal needle angles. ObjectivesThe objectives of this study were to: 1) use a dissection-based 3D modelling methodology to quantify optimal caudal needle angles from cadaveric models; and 2) compare optimal cadaver-derived caudal needle angles with real-world patient-derived needle angles. MethodsEighteen formalin embalmed lumbosacral spine specimens were dissected, digitized, and modelled in 3D. Virtual needles were simulated and placed parallel with the L1-L5 MBs. Cadaver-derived caudal needle angles were measured from the high-fidelity 3D models with optimally placed virtual needles. Lateral fluoroscopic images of patients (n = 200) that received lumbar MB denervation were reviewed to measure patient-derived caudal needle angles (L3-L5 MB levels). Descriptive statistics were used to analyze the cadaver (L1-L5 MB levels) and patient-derived (L3-L5 MB levels) caudal needle angles. The cadaver and patient-derived mean caudal needle angles for L3-L5 MB levels were compared. ResultsThere was variability in the cadaver-derived mean caudal needle angles. The lowest mean caudal needle angle was the L1 MB level measured at 41.57 ± 8.56° (range: 27.14° - 53.96°). The highest was the L5 MB level with a mean caudal needle angle of 60.79 ± 8.55° (range: 46.97° - 79.74°). A total of 123 patients were included and 369 caudal needle angles (L3-L5 MB levels) were measured and analyzed. There was variability in the patient-derived mean caudal needle angles. The patient-derived mean caudal needle angles were 29.18 ± 8.77° (range: 11.80° - 61.31°), 33.34 ± 7.23° (range: 16.40° - 54.15°), and 49.08 ± 8.87° (range: 26.45° - 76.95°) for the L3, L4, and L5 MB levels, respectively. There was a significant difference in mean caudal needle angle between cadaver and patient-derived needle angles at the L3, L4, and L5 MB levels. ConclusionsAnalysis of cadaver-derived needle angles versus patient-derived data suggests optimization of lumbar MB denervation requires greater caudal angulation to achieve parallel needle placement. Further research is required to assess the clinical implications.

Anatomy of mamillo-accessory foramen and prevalence of ossified mamillo-accessory ligament in lumbar vertebrae related to age.

Ossification of the mamillo-accessory ligament (MAL) results in the formation of a mamillo-accessory foramen (MAF), which is associated with aging. The MAL tethers the medial branches of the lumbar dorsal rami to the lumbar vertebrae. A MAL ossified at the lumbar vertebrae can cause low back pain by compressing the medial branch of a dorsal ramus. Age ranges related to ossification of the MAL have not been reported in previous studies. The objective of the present study was to determine the prevalence of ossification of the MAL in the lumbar column and its relationship to aging, and to measure the newly formed MAF at each level of the lumbar vertebrae. This study examined 935 dried lumbar vertebrae from 187 donors at Khon Kaen University, Thailand, consisting of 93 females and 94 males. The research focused on ossification patterns of the MAL, categorizing them into three patterns. We found that over 50% of ossified MAL occurred in the 30-45-year-old range and the frequency increased with age. The prevalence of ossified lumbar MAL was 72.73%, especially in L5 on the left side in females (76.92%). The width of the MAF did not differ significantly between the sexes, but it was greater on the left side (2.46 ± 1.08; n = 76) than the right (2.05 ± 0.95; n = 72) (p = 0.016). Ossification of the MAL into the MAF progresses with age, leading to low back pain from nerve compression. Physicians should be aware of the MAF during anesthesia block to treat low back pain.

Effectiveness and cost-effectiveness of radiofrequency denervation versus placebo for chronic and moderate to severe low back pain: study protocol for the RADICAL randomised controlled trial

IntroductionLow back pain (LBP) is the leading global cause of disability. Patients with moderate to severe LBP who respond positively to a diagnostic medial nerve branch block can be offered...

Ultrasound-guided retromammillary injections in dogs: a feasibility, descriptive and anatomical study

ObjectiveTo evaluate the feasibility of an ultrasound-guided technique targeting the medial branches of the dorsal ramus of the spinal nerves (DRSN) by injecting a dye solution at the caudal aspect of the base of lumbar mammillary processes [i.e. the retromammillary (RM) space]. Study designFeasibility, descriptive, anatomical study. AnimalsEleven canine cadavers. MethodsUsing anatomical dissections, the relationship between the mammillary processes and the branches of the DRSN of the thoracolumbar and lumbar spine was studied in two cadavers. Subsequently, ultrasound-guided RM injections were administered in nine cadavers, randomly assigned to low volume (LV; 0.01 mL kg–1) of a dye solution at multiple points from L3 to L6 on one side, and high volume (HV; 0.4 mL kg–1) at a single L4 point on the contralateral side. Gross anatomical dissections were immediately performed after the injections. The RM injections were feasible if ultrasonographic landmarks were identifiable in at least 80% of cases, and 80% of LV injections showed medial branch staining. A one-sample binomial test was used for testing feasibility. ResultsThe medial branches emerged shortly after the DRSN exited the intervertebral foramen and traveled towards the caudal aspect of the base of the mammillary process, which served as the target injection point. With LV, 36 out of 36 (100%) injected medial branches were stained, meeting the criteria of feasibility (p < 0.001). The median (range) number of stained medial branches per cadaver were 4 (4–4) and 2 (1–3), with LV and HV, respectively. Although no lateral branches were stained with LV, 1 (0–2) was stained with HV. Neither ventral branch staining nor epidural spread was noted in any cadaver. Conclusions and clinical relevanceUltrasound-guided RM injections are feasible and allow for selective staining of the medial branch of the DRSN in canine cadavers at the lumbar spine.

An Explorative Anatomical Study on Inter-Individual Variation of the Tibial Nerve and Landmarks for Perineural Anesthesia in Horses.

Perineural anesthesia of the tibial nerve can be performed ultrasound-guided or blindly, with the latter still being commonly used in equine practice due to practical constraints, despite its lower accuracy and hence, common failure to achieve desensitization. This may be associated with anatomical variations or inadequate landmarks for injection. To examine the course of the tibial nerve, document potential anatomical variations, and determine optimal landmarks for perineural injection, dissection was conducted along the medial aspect of the tibia in 10 paired cadaver hindlimbs. No anatomical variations of the tibial nerve were observed. Mean tibial nerve thickness was 6 ± 1 mm. The junction with the plantar nerves was located at a maximum of 85 mm and the junction with the medial cutaneous branch was at a maximum of 150 mm proximal to the proximal aspect of the calcaneal tubercle. The mean distance of the tibial nerve to the cranial border of the superficial digital flexor was 11 ± 6 mm. In conclusion, problems with perineural anesthesia of the tibial nerve cannot simply be attributed to anatomical variations. The thickness of the nerve and the amount of perineural tissue may present specific challenges for achieving adequate desensitization. Our results support the generally recommended site for tibial nerve perineural injection at 100 mm proximal to the calcaneal tubercle and 11 mm cranial to the superficial digital flexor.

Anatomical assessments of injectate spread stratified by the volume of the intertransverse process block at the T2 level

BackgroundThis cadaveric study aimed to analyze injectate spread to target nerves during a single-injection, ultrasound-guided intertransverse process block.MethodsAn ultrasound-guided intertransverse process block with three different injectate volumes was administered to...

Poster 304: Isolating The Medial Meniscal Artery with Ultrasonography: Anatomical Characterization of the Novel Vascular Structure and a Technical Note on Imaging Technique

Objectives: The vascularity of the human meniscus was first famously described by Arnoczky and Warren, who used histological analysis to map out vessel contributions to the medial and lateral menisci. This study determined that the medial and lateral superior and inferior genicular arteries branches give rise to a perimeniscal capillary plexus within the capsular and synovial tissues of the knee. However, since this study, there have been limited investigations into the macro- and microvascularity of the menisci. This includes anatomical, biomechanical, and imaging studies. Doppler ultrasound is an easily accessible, safe, and non-invasive modality that gives clinicians real-time visualization of vascular anatomy. To date, there have been no ultrasound studies that have highlighted vascular deviations from the popliteal artery to the medical meniscus, including the newly discovered medial meniscal artery (MMA), as described in Part 1 of this study (Figure 1, from Part 1 of this investigation). The purpose of this study was to use find a reproducible ultrasound technique to identify the MMA and provide a detailed characterization of the vessel’s precise anatomy. We hypothesized that the MMA would be consistently identifiable in vivo using ultrasound imaging and that multiple anatomic variants of the MMA would exist. Methods: Fifty-six patients underwent ultrasound examination of the left knee. Patient demographics were collected. The MMA was isolated by one of two techniques. In the first approach, the inferior medial genicular artery (IMGA) was isolated and followed back to the popliteal artery, where the examiner then coursed the artery proximally to find medial-sided vasculature branching to the medial meniscus. In the second approach, the probe was started on the medial meniscus and once an arterial supply was found, it was traced back to the popliteal artery. Once the MMA was isolated by either technique, the following variables were measured: presence or absence of MMA, artery diameter, presence of arterial calcifications or atheromatous plaques, and any vascular variations. Once the MMA was found and isolated in the left knee, its presence was investigated in the right knee. Results: The MMA was identified in 50/56 patients (89.2%). The average vessel diameter was 0.89 mm (SD ± 0.39). All 50 patients with a MMA present on the left knee also had the presence of the artery on the right knee. None of the MMA isolated in this study were noted to have any plaques or calcifications. 45 patients were noted to have a Type 1 MMA, whereas five patients were noted to have a Type 2 MMA where the vessel shares an origin with the IMGA (Figure 2). Conclusions: This is the first study to utilize ultrasound to isolate and characterize the MMA in a in vivo human model. The MMA can be consistently seen on ultrasonography in the majority of patients and ultrasound examination demonstrated that the artery perforates into the meniscal tissue to contribute to the meniscal microplexus. The key methods to ensure reproducible identification of the artery and patient characteristics that produce lesser quality images are discussed in detail. Ultrasound identification in clinic may serve as a point-of-care diagnostic modality to determine the likelihood of success of procedures such as medial meniscal repair, given the artery provides a direct blood supply to the meniscus. The MMA may play a pivotal role in meniscal injury, repair, healing, and preservation. Future studies are necessary to determine the extent to which this vessel contributes to said mechanisms.

Effectiveness of the proximal medial branch in DIEP flaps for breast reconstruction using Hartrampf zone IV

BackgroundWhen performing breast reconstruction using a deep inferior epigastric artery perforator (DIEP) flap, including Hartrampf zone IV, the bipedicled DIEP flap has been argued to be necessary to ensure stable perfusion. However, a proximal medial branch (PMB), which is the most proximal perforator of the deep inferior epigastric artery, may make it possible to obtain adequate perfusion in a unilateral DIEP flap. This study aimed to clarify the detailed anatomical characteristics of PMB and its potential clinical application in breast reconstruction. MethodsThis retrospective study was conducted on breast reconstruction using the DIEP flap between May 2020 and July 2023. Data on PMB anatomy were collected from preoperative contrast-enhanced computed tomography angiography, and contralateral perfusion of the flap was estimated using intraoperative indocyanine green angiography. ResultsThe PMB was present in approximately 85% of cases, arising near the lateral border of the rectus abdominis, branching caudomedially in over half of the cases, and perforating 2.3cm laterally and 8.8cm caudally on average from the umbilicus. The average perfusion area of both zones II and IV significantly expanded to 96.5% and 74.2%, respectively, when the PMB was included in the DIEP flap, and 9 of 22 cases showed contrast extending to the entire zone IV. ConclusionsThe use of the DIEP flap with PMB is a good option for substantial-volume breast reconstruction. When utilizing the PMB, it is important to consider its specific anatomy, location of the main perforator, and pedicle length.

Radiofrequency ablation for the cervical spine.

Radiofrequency ablation (RFA), a minimally invasive procedure for pain reduction, is increasingly used for managing chronic neck pain and headaches. This article offers a concise overview of cervical spine RFA. In the context of RFA, heat is applied to specific nerve tissues to interrupt pain signals. Wallarian degeneration occurs as a result of the thermal injury to the nerve. The heat generated by the RFA procedure can damage the nerve fibers, initiating the degenerative process. Wallarian degeneration is a process that occurs in a nerve axon due to the thermal injury, leading to the breakdown and eventual degradation of the axon and its myelin sheath. However, nerves have regeneration capacity, especially the peripheral nerves, which are often the target of RFA for pain management. After Wallarian degeneration takes place, the nerve sheath, or the connective tissue surrounding the nerve, can serve as a scaffold for the growth of new nerve fibers. Over time, these new fibers can regenerate and re-establish connections, potentially restoring nerve function. Three common types are traditional thermal, water-cooled, and pulsed radio frequency ablation. Given the regenerative potential of nerves, these procedures are typically effective for 1 to 2 years, with some variability. Despite a 112% increase in Medicare claims for RFA from 2009 to 2018, it's recommended for patients who respond positively to diagnostic medial branch blocks, with recent guidelines suggesting a single block may be sufficient. Although generally effective, the procedure carries risks, including nerve and tissue injury. Notably, the procedure's increased utilization notably surpasses the most commonly reported prevalence rates of conditions it aims to treat. Moreover, diagnostic blocks performed before cervical RFA also have their risks, such as inadvertent vascular injections leading to seizures or paralysis. In summary, the risks and benefits of cervical RFA must be considered with regards to the patient's comorbidities and specific pain issues. The skill and experience of the practitioner plays a significant role in minimizing these risks. Detailed discussions with healthcare providers about the risks, benefits, and alternatives can help in making an informed decision about the procedure.

Can ultrasound-guided medial branch blocks be used to select patients for cervical facet joint radiofrequency neurotomy? A matched retrospective cohort validation study.

Medial branch blocks are used to select patients for cervical facet joint radiofrequency neurotomy (CRFN). Blocks are typically performed under fluoroscopic guidance (ie, fluoroscopy-guided blocks [FLBs]). The validity of ultrasound-guided blocks (USBs) is not well established. No prior research has compared cervical USB validity and FLB validity with CRFN outcome used as the criterion standard. To evaluate cervical USB versus FLB validity with CRFN outcome used as the criterion standard. Demographic and outcome data were extracted from the electronic medical records of 2 affiliated musculoskeletal pain management clinics for all patients between 2015 and 2023 inclusive who had cervical USB leading to CRFN. CRFN outcomes of each USB patient were compared with those of a matched FLB patient from the radiofrequency neurotomy (RFN) outcome database of the same clinics. Matching variables included patient age, sex, pain duration, diagnostic/prognostic block paradigm, and CRFN number. Each patient completed a numeric rating scale (NRS) pain score and Pain Disability Quality-of-Life Questionnaire (PDQQ) just before and 3months after CRFN. At repeat CRFN, patients provided a retrospective estimate of the duration and average magnitude (percentage) of relief after the CRFN. USB and FLB groups were comprised of 27 patients (58 RFNs) and 38 patients (58 RFNs), respectively. Post-RFN NRS pain severity and PDQQ-Spine scores demonstrated comparable (P > .05) absolute improvements, proportion of patients achieving ≥50% improvement, and attainment of the minimum clinically important difference. Retrospective estimates of pain relief magnitude and duration were also comparable. This study finds cervical USB and FLB to be comparably valid as defined by their ability to predict CRFN outcome. Within the limitations of operator competence, USB can be used to select patients for CRFN.

The Clinical Effects of C2 and C3 Medial Branch Block for Medically Intractable Headache : a Retrospective Study.

This study aimed to evaluate the clinical effects of medial branch blocks (MBB) C2 and C3 in treating patients with medically intractable headaches. The medical records of 81 patients with medically intractable headaches who underwent a C2/3 MBB between January 2019 and March 2022 were retrospectively reviewed. The degrees of pain were evaluated using a visual analogue scale (VAS) score (rating 0-10) on baseline and after procedures. To evaluate patients' satisfaction for the treatment, self-reporting measurements were examined and were categorized as excellent (>90% pain relief), good (50%-90% pain relief), fair (10%-50% pain relief), and none (<10% pain relief). The total number of MBB procedure was 107. The average baseline VAS score was 7.4 ±1.5, which improved significantly to 2.6 ±2.3, 3.6 ±2.6, and 4.5 ±3.2 on 1-3 days, 3-7 days, and 3 months after the procedure, respectively (Wilks' lambda within group test, P <0.001). For the subjective feeling of pain relief, percentages of "excellent" response in the self-reporting measurements were significantly decreased over time (chi-square test; P= 0.001). This study demonstrates clinical effectiveness of C2/3 MBB in patients with medically intractable headaches, with both early and prolonged benefits.

Rotational Evolution of Classical T Tauri Stars: Models and Observations

We developed a grid of stellar rotation models for low-mass and solar-type classical T Tauri stars (CTTS; 0.3M ⊙ < M * < 1.2M ⊙). These models incorporate the star–disk interaction and magnetospheric ejections to investigate the evolution of the stellar rotation rate as a function of the mass of the star M *, the magnetic field (B *), and stellar wind ( Ṁwind ). We compiled and determined stellar parameters for 208 CTTS, such as projected rotational velocity vsin(i) , mass accretion rate Ṁacc , stellar mass M *, ages, and estimated rotational periods using Transiting Exoplanet Survey Satellite (TESS) data. We also estimated a representative value of the mass-loss rate for our sample using the [O i] λ 6300 spectral line. Our results confirm that vsin(i) measurements in CTTS agree with the rotation rates provided by our spin models in the accretion-powered stellar winds picture. In addition, we used the approximate Bayesian computation technique to explore the connection between the model parameters and the observational properties of CTTS. We find that the evolution of vsin(i) with age might be regulated by variations in (1) the intensity of B * and (2) the fraction of the accretion flow ejected in magnetic winds, removing angular momentum from these systems. The youngest stars in our sample (∼1 Myr) show a median branching ratio Ṁwind/Ṁacc∼0.16 and median B * ∼ 2000 G, in contrast to ∼0.01 and 1000 G, respectively, for stars with ages ≳3 Myr.

Vacuum Disc Phenomenon Turned Gassy Disc Herniation: A Case Report

BACKGROUND: The vacuum phenomenon is a radiologic finding that results from gas accumulation within degenerated discs, joints, or vertebrae. This gas can herniate, causing back pain and/or radiculopathy. Asymptomatic imaging abnormalities can be coincidental and/or non-concordant with clinical presentation therefore warranting close evaluation. CASE REPORT: This 45-year-old man, previously diagnosed with lumbar facet arthropathy, returned to the clinic for left-sided axial low back pain. Imaging revealed that a gas filled mass in the right lateral recess was affecting the traversing right L5 and S1 nerve roots. Given the exclusive axial symptoms consistent with lumbar zygapophyseal joint arthropathy, the patient was treated with a repeat L3-4 medial branch and L5 dorsal ramus radiofrequency ablation and experienced subsequent near-complete pain resolution. CONCLUSIONS: Careful consideration must be taken when conducting clinical evaluation, imaging, diagnosis, and treatment of patients with low back pain given the significant frequency of abnormal, often nonconcordant, radiological findings. KEY WORDS: Pneumorrhachis, vacuum disc phenomenon, low back pain, case report

Characterization of the MSAP Flap in Head and Neck Surgical Oncology: A 3D Cadaveric Study.

The medial sural artery (MSA) perforator flap is a versatile free flap. However, the cutaneous perforators are not well characterized. The objectives of this pilot anatomical study were to: (1) visualize in three-dimensions, as in-situ, the origin, course, and distribution of the cutaneous perforators, (2) characterize the number and frequency of the perforators, and (3) quantify mean pedicle length. Thirteen cadaveric specimens were dissected, digitized, and modeled in 3D. Three-dimensional models and dissection photographs were used to determine the origin, course, number, distribution, and pedicle length of MSA perforators. The most common pattern consisted of three perforators (39% of specimens). The maximum number of perforators identified was four (23%). The majority of specimens (92%) had a cutaneous perforator originating from the lateral branch of the MSA and coursed most frequently in the second (43%) and third (37%) quartiles of the length of the tibia. Mean pedicle length was 19.1 ± 6.9 cm. Perforators originating from the medial branch of the MSA were significantly (p < 0.05) shorter than those from the lateral branch and were found to course only in the first quartile. The 3D models constructed in this study provide a comprehensive overview of the location and course of the perforators, enabling measurement of parameters in 3D-space. Anatomical characterization of the MSA perforator flap using 3D analysis can assist reconstructive surgeons in understanding the relevant anatomy and optimizing the surgical technique for flap harvest. N/A Laryngoscope, 134:4298-4303, 2024.

Differences between the healthcare systems of Quebec and France for the treatment of pain due to spinal disorders.

In Quebec, Canada, the public healthcare system offers free medical services. However, patients with spinal pain often encounter long waiting times for specialist appointments and limited physiotherapy coverage. In contrast, private clinics provide expedited care but are relatively scarce and entail out-of-pocket expenses. Once a patient with pain caused by a spinal disorder meets a pain medicine specialist, spinal intervention is quickly performed when indicated, and patients are provided lifestyle advice. Transforaminal epidural steroid injections are frequently administered to patients with radicular pain, and steroid injections are administered on a facet joint to control low back or neck pain. Additionally, medial branch blocks are performed prior to thermocoagulation. France's universal healthcare system ensures accessibility at controlled costs. It emphasizes physical activity and provides free physical therapy services. However, certain interventions, such as transforaminal and interlaminar epidural injections, are not routinely used in France owing to limited therapeutic efficacy and safety concerns. This underutilization may be a potential cause of chronic pain for many patients. By examining the differences, strengths, and weaknesses of these two systems, valuable insights can be gained for the enhancement of global spinal pain management strategies, ultimately leading to improved patient outcomes and satisfaction.

Normality analysis of numeric rating scale scores in patients with chronic axial spine pain before and after medial branch blocks: a multicenter study.

The statistical analysis typically used to compare pain before and after interventions assumes that scores are normally distributed. The present study evaluates whether numeric rating scale (NRS) scores, specifically NRS-11 scores, are indeed normally distributed in a clinically relevant cohort of adults with chronic axial spine pain before and after analgesic intervention. Retrospective review from 4 academic medical centers of prospectively collected data from a uniform pain diary administered to consecutive patients after they had undergone medial branch blocks. The pain diary assessed NRS-11 scores immediately before injection and at 12 different time points after injection up to 48 hours. D'Agostino-Pearson tests were used to test normality at all time points. One hundred fifty pain diaries were reviewed, and despite normally distributed pre-injection NRS-11 scores (K2 = 0.655, P = .72), all post-injection NRS-11 data were not normally distributed (K2 = 9.70- 17.62, P = .0001-.008). Although the results of parametric analyses of NRS-11 scores are commonly reported in pain research, some properties of the NRS-11 do not satisfy the assumptions required for these analyses. The data demonstrate non-normal distributions in post-intervention NRS-11 scores, thereby violating a key requisite for parametric analysis. We urge pain researchers to consider appropriate statistical analysis and reporting for non-normally distributed NRS-11 scores to ensure accurate interpretation and communication of these data. Practicing pain physicians should similarly recognize that parametric post-intervention pain score statistics might not accurately describe the data and should expect articles to utilize measures of normality to justify the selected statistical methods.

Multifidus atrophy and/or dysfunction following lumbar radiofrequency ablation: A systematic review.

Lumbar medial branch nerve radiofrequency ablation (LRFA) is an interventional procedure used to treat chronic lumbar facet joint pain. Because the medial branch nerves also innervate the multifidus muscle, it has been proposed that LRFA may pose a risk of multifidus atrophy and/or dysfunction. However, the quality and level of evidence to answer this clinical question have not been established. Therefore, this review aimed to systematically appraise the literature to discern whether the prevailing evidence substantiates the hypothesis in question. A systematic review compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed to evaluate the quality and level of evidence of studies reporting functional and/or structural changes in the multifidus muscle following LRFA. Only five cohort studies met inclusion criteria. Two studies assessed changes in multifidus function following LRFA with confirmed denervation at electromyography and significant reduction in multifidus shear modulus with ultrasound shear wave elastography. Of the four studies that evaluated changes in multifidus structure with magnetic resonance imaging following LRFA, two demonstrated a decrease in cross-sectional area or an increase in fat infiltration, one demonstrated no change, and one revealed an apparent increase. Given the destructive nature attributed to LRFA, some degree of multifidus atrophy and/or dysfunction may be plausible, albeit with a very low certainty that relies on a restricted body of literature of modest quality and with a presence of high bias. There is a paucity of studies discussing the potential association between LRFA and multifidus atrophy and/or dysfunction. In light of the shortage of high-quality studies and the absence of standardized protocols to assess both changes in the structure and function of the multifidus subsequent to LRFA, there is a pressing need for more prospective studies with a high methodological rigor to comprehensively address and answer this enduring debate in clinical practice.