Facet joint injections for management of low back pain: a clinically focused review

Lumbar facet joints have been implicated in chronic low back pain in up to 45% of patients with low back pain (LBP). Facet joint pain diagnosis and management are always challenging for pain physicians. Facet joint pain is not diagnosed by specific demographic features, pain characteristics, or physical findings, even though electrodiagnostic studies and imaging modalities are available. Although comparative local anesthetics or placebo saline injections can be used, diagnostic blocks are the only reliable diagnostic measures according to the current literature. Treatment of chronic LBP arising due to facet joint includes intraarticular injections, medial branch blocks, and radiofrequency neurotomy. However, the evidence of their clinical efficacy is continuously under scrutiny. Pain physicians must have a detailed understanding of the spinal anatomy in order to perform safe and effective interventional procedures. This review outlines the important aspects of spinal anatomy as they relate to interventional pain management related to facet joint injections. Additionally, we provide a comprehensive review of the procedure and clinical evidence.

New insights into pathways of the accessory nerve and transverse cervical artery for distal selective accessory nerve blockade

Background@#The aim of this study was to clarify the topographical relationship between the accessory nerve (AN) and transverse cervical artery (TCA) to provide safe and convenient injection points for AN blockade. @*Methods@#This study included 21 and 30 shoulders of 14 embalmed Korean adult cadavers and 15 patients, respectively, for dissection and ultrasound (US) examination. @*Results@#The courses of the TCA and AN in the scapular region were classified into four types based on their positional relationships. Type A indicated the nerve that was medial to the artery and ran parallel without changing its location (38%). In type B (38%), the nerve was lateral to the artery and ran parallel without changing its location. In type C (19%), the nerve or artery traversed each other only once during the whole course. In type D (5%), the nerve or artery traversed each other more than twice forming a twist. At the levels of lines I-IV, the nerve was relatively close to the artery (approximately 10 mm). TCAs were observed in all specimens around the superior angle of the scapula at the level of line II, whereas they were not found below line VI. In US images of the patients, the TCA was commonly observed at the level of line II (93.3%) where all ANs and TCAs were observed in cadaveric dissection. @*Conclusions@#The results expand the current knowledge of the relation between the AN and TCA, and provide helpful information for selective diagnostic nerve blocks in the scapular region.

New insights into pathways of the dorsal scapular nerve and artery for selective dorsal scapular nerve blockade

BACKGROUND: The aim of this study was to clarify the topographical relationships between the dorsal scapular nerve (DSN) and the dorsal scapular artery (DSA) in the interscapular region to identify safe and convenient injection points related to DSN blockade. METHODS: Thirty shoulders of embalmed Korean cadavers and 50 live subjects were used for dissection and ultrasound (US) analysis. RESULTS: The running patterns of the DSA and DSN in the interscapular region were classified into 3 types. Type I was defined as nerves that were medial to the artery and parallel without changing location (80.0% of specimens). In type II (13.3%), the nerve and artery traversed one another only one time over their entire length. In type III (6.7%), the nerve and artery traversed one another, resembling a twist. Above the level of the scapular spine, the nerve was always medial to the artery. Below the scapular spine, the number of arteries was obviously decreased. Most of the arteries were lateral to the medial border of the scapula, except at the level of the superior angle of the scapula artery (SA). The positional tendency of the DSN toward the medial or lateral sides from the medial border of the scapula was similar. In US imaging of live subjects, the DSA was most observed at the level of the SA (94.0%). CONCLUSIONS: Results of this study enhance the current knowledge regarding the pathway of the DSN and DSA and provide helpful information for selective diagnostic nerve blocks in the interscapular region.

Chronic Treatment with Combined Chemotherapeutic Agents Affects Hippocampal Micromorphometry and Function in Mice, Independently of Neuroinflammation

Chemotherapeutic agents induce long-term side effects, including cognitive impairment and mood disorders, particularly in breast cancer survivors who have undergone chemotherapy. However, the precise mechanisms underpinning chemotherapy-induced hippocampal dysfunction remain unknown. In this study, we investigated the detrimental effects of chronic treatment with a combination of adriamycin and cyclophosphamide (AC) on the neuronal architecture and functions of the hippocampi of female C57BL/6 mice. After chronic AC administration, mice showed memory impairment (measured using a novel object recognition memory task) and depression-like behavior (measured using the tail suspension test and forced swim test). According to Golgi staining, chronic AC treatment significantly reduced the total dendritic length, ramification, and complexity as well as spine density and maturation in hippocampal neurons in a sub-region-specific manner. Additionally, the AC combination significantly reduced adult neurogenesis, the extent of the vascular network, and the levels of hippocampal angiogenesis-related factors. However, chronic AC treatment did not increase the levels of inflammation-related signals (microglial or astrocytic distribution, or the levels of pro-inflammatory cytokines or M1/M2 macrophage markers). Thus, chronic AC treatment changed the neuronal architecture of the adult hippocampus, possibly by reducing neurogenesis and the extent of the vasculature, independently of neuroinflammation. Such detrimental changes in micromorphometric parameters may explain the hippocampal dysfunction observed after cancer chemotherapy.

Appearance of osteoporosis in rat experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) in Lewis rats is characterized by transient paralysis followed by recovery. To evaluate whether transient paralysis in EAE affects bone density, tibiae of EAE rats were morphologically investigated using micro-computed tomography and histology. The parameters of bone health were significantly reduced at the peak stage of EAE rats relative to those of controls (p < 0.05). The reduction of bone density was found to remain unchanged, even in the recovery stage. Collectively, the present data suggest that osteoporosis occurs in paralytic rats with monophasic EAE, possibly through the disuse of hindlimbs and/or autoimmune inflammation.

Evaluation of effect of red ginseng on ovariectomy-induced bone loss in C3H/HeN mice / 동물의과학연구지

Panax ginseng, also known as Korean ginseng, has long been used as a broad tonic in Oriental medicine to augment vitality, health, and longevity, particularly in older people. This study investigated the effects of Korean red ginseng (RG) on bone loss in ovariectomized (OVX) mice. C3H/HeN mice (10-weeks-old) were divided into sham and OVX groups. OVX mice were treated with vehicle, 17beta-estradiol (E2), RG (oral administration, 250 mg/kg/day), or RG (intraperitoneal administration, 50 mg/kg/every other day) for 6 weeks. Serum E2 concentration and alkaline phosphatase (ALP) activity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical properties and osteoclast surface level were measured. There was no significant difference in the degree of grip strength, body weight, uterine weight, mechanical property, tibiae length, or tibiae weight between the OVX and RG-treated groups. Compared with the OVX group, the serum ALP level was significantly lower in the RG-treated groups. Serum E2 levels and osteoclast surface levels did not change between the OVX and RG-treated groups. RG could not preserve trabecular bone volume, trabecular bone number, trabecular separation, trabecular thickness, structure model index, or bone mineral density of the proximal tibiae metaphysic. In conclusion, there was no definite effect of RG on OVX-induced bone loss in C3H/HeN mice.

Establishment of a murine model for radiation-induced bone loss using micro-computed tomography in adult C3H/HeN mice / 한국실험동물학회지

Bone changes are common sequela of radiation therapy for cancer. The purpose of this study was to establish an experimental model of radiation-induced bone loss in adult mice using micro-computed tomography (microCT). The extent of changes following 2 Gy gamma irradiation (2 Gy/min) was studied at 4, 8, 12 or 16 weeks after exposure. Adult mice that received 1, 2, 4 or 6 Gy of gamma-rays were examined 12 weeks after irradiation. Tibiae were analyzed using microCT. Serum markers and biomechanical properties were measured and the osteoclast surface was examined. A significant loss of trabecular bone in tibiae was evident 12 weeks after exposure. Measurements performed after irradiation showed a dose-related decrease in trabecular bone volume fraction (BV/TV) and bone mineral density (BMD), respectively. The best-fitting dose-response curves were linear-quadratic. Taking the controls into accounts, the lines of best fit were as follows: BV/TV (%)= -0.071D2-1.799D+18.835 (r2=0.968, D=dose in Gy) and BMD (mg/cm3) = -3.547D2-14.8D+359.07 (r2=0.986, D=dose in Gy). Grip strength and body weight did not differ among the groups. No dose-dependent differences were apparent among the groups with regard to mechanical and anatomical properties of tibia, serum biochemical markers and osteoclast activity. The findings provide the basis required for better understanding of the results that will be obtained in any further studies of radiation-induced bone responses.

Fast neutron irradiation deteriorates hippocampus-related memory ability in adult mice

Object recognition memory and contextual fear conditioning task performance in adult C57BL/6 mice exposed to cranial fast neutron irradiation (0.8 Gy) were examined to evaluate hippocampus-related behavioral dysfunction following acute exposure to relatively low doses of fast neutrons. In addition, hippocampal neurogenesis changes in adult murine brain after cranial irradiation were analyzed using the neurogenesis immunohistochemical markers Ki-67 and doublecortin (DCX). In the object recognition memory test and contextual fear conditioning, mice trained 1 and 7 days after irradiation displayed significant memory deficits compared to the sham-irradiated controls. The number of Ki-67- and DCX-positive cells decreased significantly 24 h post-irradiation. These results indicate that acute exposure of the adult mouse brain to a relatively low dose of fast neutrons interrupts hippocampal functions, including learning and memory, possibly by inhibiting neurogenesis.

Differential patterns of nestin and glial fibrillary acidic protein expression in mouse hippocampus during postnatal development

Intermediate filaments, including nestin and glial fibrillary acidic protein (GFAP), are important for the brain to accommodate neural activities and changes during development. The present study examined the temporal changes of nestin and GFAP protein levels in the postnatal development of the mouse hippocampus. Mouse hippocampi were sampled on postnatal day (PND) 1, 3, 6, 18, and 48. Western blot analysis showed that nestin expression was high at PND 1 and markedly decreased until PND 18. Conversely, GFAP expression was acutely increased in the early phase of postnatal development. Nestin immunoreactivity was localized mainly in the processes of ramified cells at PND 1, but expression subsequently decreased. In contrast, GFAP was evident mainly in the marginal cells of the hippocampus at PND 1, but immunoreactivity revealed satellite, radial, or ramified shapes of the cells from PND 6-48. This study demonstrates that the opposing pattern of nestin and GFAP expressions in mouse hippocampus during postnatal development occur in the early development stage (PND 1-18), suggesting that the opposing change of nestin and GFAP in early postnatal development is important for neural differentiation and positioning in the mouse hippocampus.

Cytotoxicity of gamma-ray in rat immature hippocampal neurons

This in vitro study evaluated the detrimental effect of acute gamma (gamma)-irradiation on rat immature hippocampal neurons. Rat immature hippocampal neurons (0.5 day in vitro) were irradiated with 0~4 Gy gamma-rays. Cytotoxicity was analyzed using a lactate dehydrogenase release assay at 24 h after gamma-irradiation. Radiation-induced cytotoxicity in immature hippocampal neurons increased in a dose-dependent manner. Pre-treatments of pro-apoptotic caspase inhibitors and anti-oxidative substances significantly blocked gamma-irradiation-induced cytotoxicity in immature hippocampal neurons. The results suggest that the caspase-dependent cytotoxicity of gamma-rays in immature hippocampal cultured neurons may be caused by oxidative stress.

Amifostine ameliorates recognition memory defect in acute radiation syndrome caused by relatively low-dose of gamma radiation

This study examined whether amifostine (WR-2721) could attenuate memory impairment and suppress hippocampal neurogenesis in adult mice with the relatively low-dose exposure of acute radiation syndrome (ARS). These were assessed using object recognition memory test, the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, and immunohistochemical markers of neurogenesis [Ki-67 and doublecortin (DCX)]. Amifostine treatment (214 mg/kg, i.p.) prior to irradiation significantly attenuated the recognition memory defect in ARS, and markedly blocked the apoptotic death and decrease of Ki-67- and DCX-positive cells in ARS. Therefore, amifostine may attenuate recognition memory defect in a relatively low-dose exposure of ARS in adult mice, possibly by inhibiting a detrimental effect of irradiation on hippocampal neurogenesis.

Morphometric Analysis of Tibial Bone in Three Strains of Mice Using Micro-computed Tomography / 한국실험동물학회지

This study investigated the trabecular and cortical bone microarchitecture of tibia in 14-week-old C3H/HeN, C57BL/6J and ICR mice using micro-computed tomography (micro-CT). Defined volumes of interest were scanned at a resolution of 17 micrometer (isotropic). The X-ray tube was set at photon energy of 50 kV, current of 200 microA, exposure time 1.2 sec, and a 0.5 mm-thick aluminium filter. For quantification of bone mineral density (BMD), the bone samples were scanned by micro-CT together with 2 calibration phantoms. The image slices were reconstructed using 3-dimensional CT analyzer software. C3H/HeN mice showed significantly higher levels of bone volume fraction, trabecular number and BMD, and lower levels of trabecular separation, structure model index and degree of anisotropy compared to C57BL/6J or ICR mice in trabecular bone area. So the C3H/HeN mouse appeared to be a good model animal for the study on the changes of trabecular bone with high trabecular bone mass.

Morphometric Analysis of Tibial Bone in Three Strains of Mice Using Micro-computed Tomography / 한국실험동물학회지

This study investigated the trabecular and cortical bone microarchitecture of tibia in 14-week-old C3H/HeN, C57BL/6J and ICR mice using micro-computed tomography (micro-CT). Defined volumes of interest were scanned at a resolution of 17 micrometer (isotropic). The X-ray tube was set at photon energy of 50 kV, current of 200 microA, exposure time 1.2 sec, and a 0.5 mm-thick aluminium filter. For quantification of bone mineral density (BMD), the bone samples were scanned by micro-CT together with 2 calibration phantoms. The image slices were reconstructed using 3-dimensional CT analyzer software. C3H/HeN mice showed significantly higher levels of bone volume fraction, trabecular number and BMD, and lower levels of trabecular separation, structure model index and degree of anisotropy compared to C57BL/6J or ICR mice in trabecular bone area. So the C3H/HeN mouse appeared to be a good model animal for the study on the changes of trabecular bone with high trabecular bone mass.