Epidural Fat Research Articles

Diagnostic Efficacy of Posterior Epidural Fat Interposition on Magnetic Resonance T1-Weighted Sequence in the Diagnosis of Spondylolysis

Supportive radiologic signs may be needed to diagnose spondylolysis via lumbar magnetic resonance imaging (MRI). In spondylolysis (SL), the slight displacement of the corpus forward and lamina posteriorly can cause the interposition of posterior epidural fat (EFI), which is normally segmental. This study aimed to determine the diagnostic value of EFI, an indirect sign of SL, on lumbar mid-sagittal T1-weighted MRI. The lumbar MRI of 115 randomly selected patients with SL and degenerative disc disease (DDD) was randomized and assessed for the presence or absence of EFI by two masked observers. These observers were not permitted to examine the pars region. Inter-observer agreement was tested using Cohen's kappa coefficient. EFI was positive in 98 (85%) of 115 patients with SL, 14 (12%) in the DDD group, and 6 (5%) with an upper vertebral level adjacent to the SL. The difference was statistically significant (P < 0.01). In patients with SL, the EFI positivity rate was highest at L5 (94%) and lowest at L3 (33%). EFI positivity was observed in 13% of the patients with DDD. The specificity, sensitivity, positive predictive value, negative predictive value, and accuracy of EFI in diagnosing SL were mean 79%, 89%, 96%, 86%, and 96%, respectively. The highest diagnostic value of EFI was at the L5 level, where intra- and inter-observer reliability were nearly perfect. Epidural fat interposition is an indirect radiological finding with high reliability in diagnosing spondylolysis with mid-sagittal T1-weighted images in lumbar MRI.

The involvement of epidural fat in ossification of the ligamentum flavum: From the perspective of exosomal proteome

Ossification of the ligamentum flavum (OLF) is the primary etiology of thoracic spinal stenosis. The functional properties of epidural fat (EF), an adipose tissue located in close proximity to ligamentum flavum (LF), have been scarcely investigated. The metabolic state of adipocytes significantly influences their functionality, and exosomes play a pivotal role in intercellular communication. This study aimed to investigate the role of EF-derived exosomes in OLF and characterize their protein profile by proteomics analysis. Our findings demonstrate that exosomes obtained from EF adjacent to OLF possess the ability to enhance osteogenesis of fibroblasts in vitro. Furthermore, proteomics analysis revealed metabolic dysfunction in EF adipocytes and identified lactate dehydrogenase A (LDHA) as a potential mediator involved in the development of OLF. This study provides new insights into the pathogenic mechanism underlying OLF and offers a theoretical basis for preventing and treating ligament ossification.

Clinical, magnetic resonance imaging and computed tomography imaging findings in a young cat with epidural pyogranulomatous steatitis

AbstractA 4‐month‐old male domestic shorthair cat with a 36‐h history of acute and progressive painful paraplegia was referred. The neurological examination was consistent with T3‒L3 myelopathy. Magnetic resonance imaging of the thoracolumbar region revealed an extradural mass at the level of T12‒T13 that caused moderate spinal cord compression. The cat underwent T12‒T13 dorsal laminectomy decompressive surgery, and its neurological signs improved shortly after surgery. A diagnosis of epidural spinal steatitis was reached based on histopathological examination of the compressive mass. To the authors’ best knowledge, this is the first description of the magnetic resonance imaging and computed tomographic findings of histopathologically confirmed idiopathic sterile pyogranulomatous inflammation of epidural fat in a cat. Epidural idiopathic sterile pyogranulomatous steatitis should be included as a possible differential diagnosis in young cats with acute and progressive T3‒L3 myelopathy signs.

The Composition of the L5-S1 Neural Foramen on MRI—A Retrospective Cohort Study Examining the Anatomy Relevant to Transforaminal Epidural Steroid Injections

Transforaminal epidural steroid injections are commonly used for the treatment of radicular pain. Some providers opt for an antero-superior approach and others a postero-inferior approach. In this retrospective cohort study, we evaluated MRI evident anatomic differences between the antero-superior and postero-inferior neural foramen at L5-S1 that may be relevant when choosing an approach for injections. A total of 29 L5-S1 neural foramina that were targeted for transforaminal epidural steroid injections were included. Pre-procedure MRIs were assessed for the distribution of the fat within the foramen. Additionally, the presence of foraminal vessels and foraminal stenosis and the presence/absence of anterolisthesis was also observed. Final imaging data were obtained by majority opinion of three or four radiologists. There was a statistically significant difference in the distribution of foraminal fat between the postero-inferior foramen and the antero-superior foramen (p &lt; 0.001), with more fat generally in the postero-inferior foramen. Foraminal vessels were not consistently visualized. There was weak inter-reader reliability for the presence of vessels. In conclusion, this study suggests that there is a difference in the distribution of foraminal epidural fat between the postero-inferior and antero-superior foramen at L5-S1. Through MRI, vessels are inconsistently visualized and cannot be reliably detected on conventional MRI between readers.

MRI parameters predict central lumbar spinal stenosis combined with redundant nerve roots: a prospective MRI study.

To observe changes in the cauda equina nerve on lumbar MRI in patients with central lumbar spinal stenosis (LSS). 878 patients diagnosed with LSS by clinical and MRI were divided into the redundant group (204 patients) and the nonredundant group (674 patients) according to the presence or absence of redundant nerve roots (RNRs). The anteroposterior diameter of the spinal canal (APDS) and the presence of multiple level stenosis, disc herniation, thickening of ligamentum flavum (LF) and increased epidural fat were assessed on MRI. Univariate and multivariate logistic regression analyses were performed to explore the predictors of LSS combined with RNRs. Patients with LSS combined with RNRs had thicker epidural fat, smaller APDS and more combined multifaceted stenosis. Female patients and older LSS patients were more likely to develop RNRs; there was no difference between two groups in terms of disc herniation (p > 0. 05). Age, APDS, multiple level stenosis, and increased epidural fat were significantly correlated with the formation of LSS combined with RNRs (p < 0.05). A smaller APDS and the presence of multiple level stenosis, thickening of LF, and increased epidural fat may be manifestations of anatomical differences in patients with LSS combined with RNRs. Age, APDS, multiple level stenosis, and increased epidural fat play important roles. The lumbar spine was measured and its anatomy was observed using multiple methods, and cauda equina changes were assessed to identify the best anatomical predictors and provide new therapeutic strategies for the management of LSS combined with RNRs.

Barrier methods of prevention of epidural fibrosis at the lumbar level after microdiscectomy

The problem of cicatrical adhesion formation not only after microdiscectomies, but also after any spine surgery, remains unresolved to this day, being one of the main issues of spinal surgery. Several trigger mechanisms can be identified in the pathogenesis of epidural fibrosis formation: interaction of intervertebral cartilage components with surrounding tissues, disruption of vertebral canal integrity, dystrophy or complete absence of epidural fat, and presence of blood in the postoperative area. The pain syndrome associated with epidural fibrosis is persistent and increases after walking and prolonged being upright. There may be hyperaesthesia or hyperpathia in the innervation area of the affected roots and brisk tendon reflexes. Many authors are now trying to predict epidural fibrosis by analyzing immunological parameters and osteoprotegerin levels in blood serums, assessing anthropometric measures of patients, and examining the blood coagulation system. In modern neurosurgical society there is a clear view that epidural fibrosis should be prevented, but there are many prevention techniques. The following techniques have been identified: ligamentum flavum plasty and different variants of this operation, placement of an autograft from the inner flap of lumbar fascia into the intercostal space, use of autologous fat, use of fibrin glue, fibrous ring plasty, use of biodegradable membrane, application of anti-adhesion resorbable gel, insertion of wound drainage, use of amniotic sac, chitosan compounds in combination with L-glutamic acid, and many others.

Full Title: Is epidural and subcutaneous fat tissue thickness associated with lumbar disc herniation? Short Title: Epidural and subcutaneous fat tissue in disc herniation

Objective: Lumbar disc herniations(LDH) cause important clinical symptoms such as low back pain(LBP) and have many causes. This study investigates the role of epidural and subcutaneous fat tissue thickness in LDH. Materials and Methods: In this cross-sectional study, individuals aged 18-83 with lumbar magnetic resonance imaging (MRI) due to LBP were evaluated retrospectively between July 2023 and January 2024. According to lumbar MRI, they were divided into two groups: those with or without herniation. Both groups measured epidural fat tissue thickness(EFTT) and subcutaneous fat tissue thickness(SFTT) at all lumbar levels. The relationship between the two groups in terms of EFTT and SFTT was examined statistically. Results: According to lumbar MRI, herniation was detected in 292 patients, and no herniation was detected in 300 patients. SFTT was found to be greater in the group with herniation than in the group without herniation at all lumbar levels (p = 0.0001). EFTT was lower in the group with herniation at all levels (p = 0.0001). In the group with herniation, there was a statistically significant correlation between the number of hernia levels and SFTT (r: 0.54, p: 0.0001) and EFTT negatively (r: -0.22, p: 0.0001). Conclusion: An increase in SFTT thickness and a decrease in EFTT are associated with disc herniation. This relationship is a result of the mechanical and inflammatory damage caused by obesity. In addition, the relationship between herniation and the decrease in EFTT demonstrates the protective function of epidural fat tissue.

Transthyretin amyloid deposition in ligamentum flavum (LF) is significantly correlated with LF and epidural fat hypertrophy in patients with lumbar spinal stenosis

Lumbar spinal stenosis (LSS) is a degenerative disease characterized by intermittent claudication and numbness in the lower extremities. These symptoms are caused by the compression of nerve tissue in the lumbar spinal canal. Ligamentum flavum (LF) hypertrophy and spinal epidural lipomatosis in the spinal canal are known to contribute to stenosis of the spinal canal: however, detailed mechanisms underlying LSS are still not fully understood. Here, we show that surgically harvested LFs from LSS patients exhibited significantly increased thickness when transthyretin (TTR), the protein responsible for amyloidosis, was deposited in LFs, compared to those without TTR deposition. Multiple regression analysis, which considered age and BMI, revealed a significant association between LF hypertrophy and TTR deposition in LFs. Moreover, TTR deposition in LF was also significantly correlated with epidural fat (EF) thickness based on multiple regression analyses. Mesenchymal cell differentiation into adipocytes was significantly stimulated by TTR in vitro. These results suggest that TTR deposition in LFs is significantly associated with increased LF hypertrophy and EF thickness, and that TTR promotes adipogenesis of mesenchymal cells. Therapeutic agents to prevent TTR deposition in tissues are currently available or under development, and targeting TTR could be a potential therapeutic approach to inhibit LSS development and progression.

Minimally Invasive Transforaminal Lumbar Interbody Fusion (MI-TLIF): A Video Technique Guide.

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has been established as an excellent alternative to the traditional open approach for the treatment of degenerative conditions of the lumbar spine1-3. The procedure is performed with the patient under general anesthesia and on a radiolucent table in order to allow for intraoperative fluoroscopy. The procedure is performed through small incisions made over the vertebral levels of interest, typically utilizing either a fixed or expandable type of tubular dilator, which is eventually seated against the facet joint complex4. A laminectomy and/or facetectomy is performed in order to expose the disc space, and the ipsilateral neural elements are visualized5. The end plates are prepared, and an interbody device is placed after the disc is removed. Pedicle screws and rods are then placed for posterior fixation. Nonoperative alternatives include physical therapy and corticosteroid injections. Other operative techniques include open TLIF or other types of lumbar fusion approaches, such as posterior lumbar interbody fusion (PLIF), anterior lumbar interbody fusion, lateral or extreme lateral interbody fusion, or oblique lumbar interbody fusion. Open TLIF was developed in order to obtain a more lateral approach to the lumbar disc space than was previously possible with PLIF. The goal of this was to minimize the amount of thecal-sac and nerve-root retraction required during PLIF4. Additionally, as the number of patients who required revision after PLIF increased, the need arose for an approach to the lumbar spine that circumvented the posterior midline scarring from previous PLIF surgical sites6. MI-TLIF was introduced to reduce the approach-related paraspinal muscle damage of open TLIF5. Indications for MI-TLIF include most degenerative pathology of the lumbar spine, including disc herniation, low-grade spondylolisthesis, and spinal and foraminal stenosis7. However, MI-TLIF allows for less robust correction of deformity than other minimally invasive approaches; therefore, MI-TLIF may not be as effective in cases of substantial spinal deformity or high-grade spondylolisthesis8. MI-TLIF results in significantly less blood loss, postoperative pain, and hospital length of stay compared with open TLIF1-3. Although some studies have suggested increased operative time for MI-TLIF9,10, meta-analyses have shown comparable operative times between the 2 techniques1-3. It is thought that the discrepancy in reported operative times is the result of a learning curve and that, once that is overcome, the difference in operative time between the 2 techniques becomes minimal11,12. One disadvantage of MI-TLIF that has remained constant in the literature is its increased intraoperative fluoroscopy time compared with open TLIF3,13. The complication rate has largely been found to be equivalent between open and MI-TLIF1-3 or slightly lower with MI-TLIF14, especially in the hands of an experienced surgeon15. Finally, the fusion rate and improvement in patient outcome scores have also been found to be largely equivalent1-3. We suggest placing the ipsilateral pedicle screw after the interbody cage has been inserted.Fully visualize the Kambin triangle16 prior to performing the facetectomy. Protect the exiting and traversing nerve roots by placing small cottonoids around them and retracting delicately.Bone removed during facetectomy can be utilized as autograft for the interbody cage.Avoid removing pedicle bone during decompression.If central stenosis is present, the neural decompression should be extended medial to the epidural fat so that the dura mater can be visualized all of the way to the contralateral pedicle.Perform an adequate end plate preparation prior to interbody insertion while being mindful to avoid injuring the end plate, to minimize the risk of future cage subsidence.Confirm correct placement of the interbody device on intraoperative fluoroscopy.If bone morphogenic protein is utilized, be careful not to pack too much posteriorly as this may cause nerve irritation. TLIF = transforaminal lumbar interbody fusionMI-TLIF = minimally invasive TLIFPLIF = posterior lumbar interbody fusionALIF = anterior lumbar interbody fusionLLIF = lateral lumbar interbody fusionXLIF = extreme lateral interbody fusionOLIF = oblique lumbar interbody fusionDLIF = direct lateral interbody fusionMRI = magnetic resonance imagingA/P = anteroposteriorEMG = electromyographicBMP = bone morphogenic proteinXR = x-ray (radiograph)OTC = over the counterDVT = deep vein thrombosisPE = pulmonary embolismMI = myocardial infarctionMIS = minimally invasive surgeryOR = operating roomLOS = length of stayVAS = visual analog scaleODI = Oswestry Disability IndexM-H = Mantel-HaenszelRR = risk ratioCI = confidence intervalNSAIDs = nonsteroidal anti-inflammatory drugs.

Value of CT in targeted CT-guided epidural blood patching: Predictors for successful epidural punctures

Background and purposeDifferentiating epidural from intrathecal punctures before computed tomography (CT)-guided epidural blood patching (EBP) is subjective, relying on operator experience. This study aimed to investigate CT findings for epidural and intrathecal punctures and identify reliable predictors for successful epidural punctures before targeted CT-guided EBP. Materials and methodsWe included 65 patients with low-cerebrospinal fluid (CSF)-pressure headache receiving targeted CT-guided EBP between January 2021 and October 2022 in this retrospective study. We analyzed clinical data, technical information, and CT features before EBP. Fisher's exact test was used for discrete variables, while Mann–Whitney U test was used for continuous variables. Positive (PLR) and negative likelihood ratios (NLR) were calculated to identify predictors for confirming epidural punctures. ResultsWe confirmed 43 patients as epidural punctures and 22 patients as intrathecal punctures. Before contrast injection, epidural fat at the needle tip in the epidural group was higher than the intrathecal group (37.2 % [16/43] vs. 4.5 % [1/22], p = 0.006). After contrast injection, the “contrast-needle tip connection” sign was mostly observed in the epidural group than the intrathecal group (95.3 % [41/43] vs. 9.1 % [2/22], p < 0.001). Additionally, the epidural group had significantly higher boomerang-shaped contrast morphology than the intrathecal group (65.1 % [28/43] vs. 9.1 % [2/22], p < 0.001). The “contrast-needle tip connection” sign had the highest PLR (10.49) and lowest NLR (0.05). ConclusionIdentifying epidural fat at the needle tip, “contrast-needle tip connection” sign, and boomerang-shaped contrast morphology on CT scans are useful for confirming proper placement of the needle tip within the epidural space.

MR imaging differentiating features between lytic and degenerative lumbosacral spondylolisthesis.

Spondylolisthesis is characterized by the displacement of one vertebral body in relation to the adjacent vertebra. It is commonly observed in the lower lumbar region and can be caused by a variety of factors, including spondylolysis (a fracture in the pars interarticularis) or degenerative disease. Magnetic resonance imaging (MRI) is becoming increasingly popular as the primary modality for evaluation of low back pain and is often used in the absence of radiographs or Computed Tomography. However, it can be challenging for radiologists to differentiate between the two types of spondylolisthesis based on MRI alone. The goal of this article is to identify key imaging features on MRI that can aid radiologists in differentiating between spondylolysis and degenerative spondylolisthesis on MRI. Five key concepts are discussed: the "step-off" sign, the "wide canal" sign, T2 cortical bone signal on MRI, epidural fat interposition, and fluid in the facet joints. The utility, limitations and potential pitfalls of these concepts are also discussed to provide a comprehensive understanding of their use in differentiating between the two types of spondylolisthesis on MRI.

Assessment of epidural fat at C7-T1 with image review prior to cervical interlaminar epidural steroid injections.

Journal Article Accepted manuscript Assessment of epidural fat at C7-T1 with image review prior to cervical interlaminar epidural steroid injections Get access Paul M Kitei, MD, Paul M Kitei, MD Department of Rehabilitation Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PennsylvaniaDepartment of Physical Medicine & Rehabilitation, Rothman Orthopaedic Institute, Philadelphia, Pennsylvania Corresponding author (Paul M. Kitei, paul.kitei@rothmanortho.com). Search for other works by this author on: Oxford Academic PubMed Google Scholar David E Surrey, MD, David E Surrey, MD Department of Physical Medicine & Rehabilitation, Rothman Orthopaedic Institute, Philadelphia, Pennsylvania Search for other works by this author on: Oxford Academic PubMed Google Scholar David S Stolzenberg, DO, David S Stolzenberg, DO Department of Rehabilitation Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PennsylvaniaDepartment of Physical Medicine & Rehabilitation, Rothman Orthopaedic Institute, Philadelphia, Pennsylvania Search for other works by this author on: Oxford Academic PubMed Google Scholar Jeremy I Simon, MD Jeremy I Simon, MD Department of Rehabilitation Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PennsylvaniaDepartment of Physical Medicine & Rehabilitation, Rothman Orthopaedic Institute, Philadelphia, Pennsylvania Search for other works by this author on: Oxford Academic PubMed Google Scholar Pain Medicine, pnad050, https://doi.org/10.1093/pm/pnad050 Published: 22 April 2023 Article history Received: 04 April 2023 Revision received: 16 April 2023 Accepted: 18 April 2023 Published: 22 April 2023

After drilling superior articular process via posterolateral approach, bleeding from epidural fat tissue occurred. The bleeding stopped by water pressure of irrigation saline solution by blocking the outflow from working channel but not by the electrocoagulation using bipolar coagulator. Absorbable hemostatic gauze immediately stopped the bleeding and the hemostasis continued after removal of the gauze.

After drilling superior articular process via posterolateral approach, bleeding from epidural fat tissue occurred. The bleeding stopped by water pressure of irrigation saline solution by blocking the outflow from working channel but not by the electrocoagulation using bipolar coagulator. Absorbable hemostatic gauze immediately stopped the bleeding and the hemostasis continued after removal of the gauze.

Correlation of spinal epidural fat volume with body mass index: a longitudinal study

PurposeSpinal epidural lipomatosis is abnormal accumulation of normal fat in the epidural space with weight loss suggested as first-line therapy in select symptomatic patients. However, moderate to large longitudinal studies establishing concordant changes between body mass index and epidural fat are lacking. The purpose of this study was to longitudinally assess this relationship. MethodsWe performed an ancillary study of the Habitual Diet and Avocado Trial. Baseline and six-month abdominal MRIs were analyzed for 98 overweight or obese but otherwise healthy subjects. Dorsal epidural fat volumes in the lumbar spine were measured and correlated with changes in body mass index, changes in visceral fat volume, and demographic information. ResultsThere was a linear relationship between body mass index changes and epidural fat volume changes with a one-point change in body mass index corresponding to a 45 mm3 change in dorsal epidural fat volume (p < 0.001, 95% CI 31.87 to 76.77) as well as between visceral fat volume changes and epidural fat volume changes (regression coefficient 0.51, p < 0.001, 95% CI 0.22 to 0.47). Age was inversely related with subjects older than 45.7 years tending to lose epidural fat (regression coefficient −0.22, p = 0.025, 95% CI -10.43 to −0.72). ConclusionChanges in spinal dorsal epidural fat volume parallel changes in body mass index and visceral fat, supporting weight loss as initial treatment for uncomplicated obesity-associated spinal epidural lipomatosis.

Management of dynamic cervical kyphosis with dorsal epidural lipomatosis: a Hirayama disease variant? Illustrative case.

Hirayama disease, a cervical myelopathy characterized most commonly by a self-limiting atrophic weakness of the upper extremities, is a rare entity, scarcely reported in the literature. Diagnosis is made by spinal magnetic resonance imaging (MRI), which typically shows loss of normal cervical lordosis, anterior displacement of the cord during flexion, and a large epidural cervical fat pad. Treatment options include observation or cervical immobilization by collar or surgical decompression and fusion. Here, the authors report an unusual case of a Hirayama-like disease in a young White male athlete who presented with rapidly progressive paresthesia in all 4 extremities and no weakness. Imaging showed characteristic findings of Hirayama disease as well as worsened cervical kyphosis and spinal cord compression in cervical neck extension, which has not previously been reported. Two-level anterior cervical discectomy and fusion and posterior spinal fusion improved both cervical kyphosis on extension and symptoms. Given the disease's self-limiting nature, and a lack of current reporting, there remains no consensus on how to manage these patients. Such findings presented here demonstrate the potentially heterogeneous MRI findings that can be observed in Hirayama disease and emphasize the utility of aggressive surgical management in young, active patients whereby a cervical collar may not be tolerated.

Could Spinal Epidural Lipomatosis Be the Hallmark of Metabolic Syndrome on the Spine? A Literature Review with Emphasis on Etiology.

Spinal epidural lipomatosis is defined by an excessive amount of epidural fat in the spinal canal, usually in the lumbosacral tract: a well-known cause of lumbar pain and spinal stenosis with a possible wide range of neurological symptoms. Recent research data reveal that, nowadays, obesity has become the main cause of spinal epidural lipomatosis. Moreover, this condition was recently recognized as a previously unknown manifestation of metabolic syndrome. Radiological studies (CT and MRI) are the only tools that are able to diagnose the disease non-invasively. Indeed, radiologists play a key role in disease recognition, with subsequent possible implications on patients' systemic health assessments. Despite its clinical importance, the condition is still underreported and neglected. The current literature review summarizes all the main etiologies of spinal epidural lipomatosis, particularly regarding its linkage with metabolic syndrome. An overview of disease characteristics from diagnosis to treatment strategies is also provided.

Arachnoiditis Extending Beyond Operative Site

Lumbar epidural fibrosis may occur after a lumbar discectomy, replacing normal epidural fat with non-physiologic scar tissue, binding the dura and nerve roots to the surrounding structures, and causing arachnoiditis. Lumbar arachnoiditis occurs in 6%-16% of postoperative surgeries in the lumbar region, usually at the site of the laminectomy into the spinal canal. This case report covers a 35-year-old male patient who underwent a discectomy with resulting arachnoiditis multiple levels cranial of the site of laminectomy.We illustrate the first reported case of diffuse arachnoiditis causing residual pain after a lumbar discectomy.

Fibrotic and inflammatory characteristics of epidural fat adjacent to the ossification area in patients with ossification of the ligament flavum.

To observe histological and inflammatory characteristics of epidural fat (EF) adjacent to the ossification area in patients with ossification of the thoracic ligament flavum (TOLF) and provide a preliminary research basis for investigating the impact of the EF on OLF. Samples of EF and autologous subcutaneous adipose tissue (SCAT) from TOLF patients (n=26) and non-TOLF patients (n=23) were harvested during posterior thoracic spine surgery. Adipocyte size and fibrosis were measured by histology. Vascularization and inflammatory cell infiltration were evaluated by immunohistochemical staining. Adipogenesis-related genes were assessed by real-time quantitative PCR. Conditioned media from cultured EF were evaluated via enzyme-linked immunosorbent assay to detect the secretion of inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor (TNF-α), and leptin. The phosphorylated STAT3 protein level in ligament flavum (LF) was examined using Western blot. Adipocytes size in EF was similar between in the TOLF and non-TOLF groups, but significantly smaller than that from autologous SCAT. Adipogenesis-related mRNA expression in EF was lower than that in SCAT. More fibrosis and vascularization were found in TOLF than in non-TOLF. EF in the TOLF group exhibited more macrophages and B lymphocytes infiltrated. The levels of cytokines such as IL-6, TNF-α, and leptin secreted by EF were significantly higher in the TOLF group than non-TOLF. The level of phosphorylated STAT3 in LF was significantly upregulated in the TOLF group. Morphologically, EF adjacent to the ossification area is smaller and more uniform than autologous SCAT, exhibiting a characteristic similarity to visceral fat. EF in the TOLF group shows a more fibrotic, vascularized, and inflammatory phenotype, which secretes multiple cytokines. The phosphorylated STAT3 protein was significantly upregulated in the TOLF group. Whether these properties of EF directly affect the process of OLF needs to be further explored.

Prx1+ MPCs Accumulate in the Dura Mater of Wild-Type and p21-/- Mice Followed by a Specific Reduction in p21-/- Dural MPCs.

Epidural fat contains a population of mesenchymal progenitor cells (MPCs), and this study explores the behavior of these cells on the adjacent dura mater during growth and in response to injury in a p21 knockout mouse model. p21-/- mice are known to have increased cell proliferation and enhanced tissue regeneration post-injury. Therefore, it is hypothesized that the process by which epidural fat MPCs maintain the dura mater can be accelerated in p21-/- mice. Using a Prx1 lineage tracing mouse model, the epidural fat MPCs are found to increase in the dura mater over time in both C57BL/6 (p21+/+ ) and p21-/- mice; however, by 3weeks post-tamoxifen induction, few MPCs are observed in p21-/- mice. These endogenous MPCs also localize to dural injuries in both mouse strains, with MPCs in p21-/- mice demonstrating increased proliferation. When epidural fat MPCs derived from p21-/- mice are transplanted into dural injuries in C57BL/6 mice, these MPCs are found in the injury site. It is demonstrated that epidural fat MPCs play a role in dural tissue maintenance and are able to directly contribute to dural injury repair. This suggests that these MPCs have the potential to treat injuries and/or pathologies in tissues surrounding the spinal cord.

Anatomic description of the basivertebral nerve and meningeal branch of the spinal nerve in the dog

PurposeThe existence of the basivertebral nerve and meningeal branch of the spinal nerve has not been proven in dogs to date. The objectives of this study are to 1) determine whether dogs have a meningeal branch of the spinal nerve (MBSN) and a basivertebral nerve (BVN) and to (2) describe anatomical characteristics of these two nerves. Authors also put forward a discussion on the possible clinical relevance of these findings. Material and methodsDissections were performed on six embalmed dogs at the Veterinary Faculty of Barcelona with the use of stereomicroscopy and microsurgery equipment. ResultsThe MBSN (grossly) and BVN (grossly and histologically) were identified in the cervical, thoracic, and lumbar region in all dog specimens. In addition, other small fibers (suspected nerves) entering the vertebral body through small foramina close to the end plates were identified. Histological examination of the tissues confirmed the presence of nerve fibers (myelinated and unmyelinated) in suspected BVN samples. Results of the present study indicated that dogs have BVNs. Also, suspected nerve fibers were identified among the epidural fat, running from the intervertebral foramina, that likely represent the MBSN. ConclusionThese findings open up the discussion on extrapolation of treatment options employed in human medicine for “low back pain”, such as BVN ablation, which is discussed in this article. Further anatomic and clinical studies of the innervation for the vertebral body, periosteum, vasculature, dorsal longitudinal ligament and anulus fibrosus are necessary to elucidate possible anatomical variants and breed differences as well as potential clinical (e.g., therapeutic) relevance.