L5 Lumbar Research Articles

Biomechanical analysis of lumbar interbody fusion with an anisotropic hyperelastic model for annulus fibrosis

Based on computed tomography scanning images, this paper developed a detailed finite element model for the human L2–L4 lumbar spine segment with or without L3–L4 fusion. The model included vertebrae, intervertebral disc, facet articulating surfaces and various ligaments. A previously developed hyperelastic fibre-reinforced constitutive model was used to characterize the material property of annulus fibrosus. Numerical results of L3–L4 motion unit such as load–displacement curves and nucleus pressure were compared with experimental data to validate the FE model. The normal and fused lumbar spine segments under various loading conditions, such as flexion, extension and axial rotation, were analysed. The motion range and stress distribution of the L2–L4 models under different loading conditions were then obtained to investigate the effect of lumbar fusion operation. It was shown that under the same loading condition, the fused model had a much smaller body motion range. Interbody fusion brought out obviously different stress distribution in adjacent intervertebral disc annulus fibrosus. And it also increased the intradiscal pressure of adjacent intervertebral disc significantly.

Melanocortin 4 receptor antagonists attenuates morphine antinociceptive tolerance, astroglial activation and cytokines expression in the spinal cord of rat

Chronic use of morphine is accompanied by the development of morphine tolerance, which is one of the major problems associated with opiate treatment. Experimental evidence indicates that melanocortin 4 receptor (MC4R) is involved in development of morphine tolerance. Therefore, we investigated the influence of repeated intrathecal injection of a MC4R antagonist (HS014) on the development of morphine tolerance as measured by hot-plate test. It was also examined whether a single i.t. HS014 administration could counteract the loss of analgesic potency of morphine in morphine tolerant rats. We examined also the influence of i.t. HS014 administration on astrocytes activation and cytokines expression in the spinal cord of rat during morphine tolerance. Morphine treatment (10mg/kg, i.p. twice daily) over 5 days induced tolerance as reflected by a significant reduction of withdrawal latency from 29.67±1.81s to 8.67±1.70s in the hot-plate test. Repeated coadministration of HS014 and morphine, significantly prevented the development of morphine tolerance. A single administration of an MC4R antagonist restored morphine analgesic potency in morphine tolerant rats. Using immunohistochemical staining, we demonstrated the administration of MC4R during the induction of morphine tolerance inhibited the activation of astrocytes; reduced the expression of proinflammatory cytokines interleukin-1β, IL-6, and tumor necrosis factor-α; upregulated the expression of anti-inflammatory cytokines IL-10 at the L5 lumbar spinal cord. These results suggest that MC4R may be involved in the mechanisms of morphine tolerance and antagonists of this receptor may be a possible new target in the search for strategies preventing the development of morphine tolerance.

Neuroprotective Effects of N-Acetyl-Cysteine and Acetyl-L-Carnitine after Spinal Cord Injury in Adult Rats

Following the initial acute stage of spinal cord injury, a cascade of cellular and inflammatory responses will lead to progressive secondary damage of the nerve tissue surrounding the primary injury site. The degeneration is manifested by loss of neurons and glial cells, demyelination and cyst formation. Injury to the mammalian spinal cord results in nearly complete failure of the severed axons to regenerate. We have previously demonstrated that the antioxidants N-acetyl-cysteine (NAC) and acetyl-L-carnitine (ALC) can attenuate retrograde neuronal degeneration after peripheral nerve and ventral root injury. The present study evaluates the effects of NAC and ALC on neuronal survival, axonal sprouting and glial cell reactions after spinal cord injury in adult rats. Tibial motoneurons in the spinal cord were pre-labeled with fluorescent tracer Fast Blue one week before lumbar L5 hemisection. Continuous intrathecal infusion of NAC (2.4 mg/day) or ALC (0.9 mg/day) was initiated immediately after spinal injury using Alzet 2002 osmotic minipumps. Neuroprotective effects of treatment were assessed by counting surviving motoneurons and by using quantitative immunohistochemistry and Western blotting for neuronal and glial cell markers 4 weeks after hemisection. Spinal cord injury induced significant loss of tibial motoneurons in L4–L6 segments. Neuronal degeneration was associated with decreased immunostaining for microtubular-associated protein-2 (MAP2) in dendritic branches, synaptophysin in presynaptic boutons and neurofilaments in nerve fibers. Immunostaining for the astroglial marker GFAP and microglial marker OX42 was increased. Treatment with NAC and ALC rescued approximately half of the motoneurons destined to die. In addition, antioxidants restored MAP2 and synaptophysin immunoreactivity. However, the perineuronal synaptophysin labeling was not recovered. Although both treatments promoted axonal sprouting, there was no effect on reactive astrocytes. In contrast, the microglial reaction was significantly attenuated. The results indicate a therapeutic potential for NAC and ALC in the early treatment of traumatic spinal cord injury.

Early effects of zoledronic acid and teriparatide on bone microarchitecture, remodeling and collagen crosslinks: Comparison between iliac crest and lumbar vertebra in ewes

Iliac crest bone biopsies are used to assess the mechanism of action of drug treatments, yet there are little data comparing this site to sites prone to fracture. The purpose of this study was to compare the delay and the amplitude of responses to treatment in two different bone sites. The short‐term effects of zoledronic acid and teriparatide on microarchitecture, collagen crosslinks and bone remodeling were evaluated in iliac crest and lumbar vertebrae. Aged ewes (n=8/gr) received either vehicle (CTRL) or a single injection of zoledronic acid (ZOL, 10mg) or daily injections of teriparatide (TPTD, 20μg/d) for 3months. Blood samples were collected monthly for assessing bone turnover markers. At the end of the study, a transiliac bone biopsy (IC) and L1 lumbar vertebrae (LV1) were collected to assess bone microarchitecture; pyridinoline (PYD), deoxypyridinoline (DPD), pentosidine (PEN) content, static and dynamic parameters of bone remodeling. In CTRL, Tb-BV/TV was significantly higher in LV1 than IC (p<0.0001). This was associated with a trend of higher Tb.N, Tb.Th, DA, an inferior Conn.D and a lower bone turnover as shown by the decreases of osteoid parameters, MS/BS, Ac.f in LV1 when compared to IC. In addition, the ratio PYD/DPD was 4 times higher in LV1 than IC. After 3months, significant decreases of sALP (p<0.001) and sCTX (p<0.001) were observed in the ZOL-group whereas in TPTD-group, after transient increases, they returned to baseline values. When compared to their respective CTRL, ZOL induced significant increases in Tb.BV/TV, Conn.D, Tb.N and Tb.Sp, in IC but not in LV1. Regardless of the site, ZOL markedly depressed the bone turnover: The static parameters of bone formation significantly decreased and the diminution of MS/BS, BFR/BS and Ac.f varied from −94 to −98% vs CTRL (p<0.01 to 0.001). It was associated with a diminution of the DPD content and the PYD/DPD ratio mainly in IC cortices. In contrast, after 3months, TPTD did not modify the 3D structure and microarchitecture in IC and LV1, except a trend of higher Conn.D in IC, compared to IC-CTRL. TPTD treatment induced a significant increase in cortical porosity in LV1 (p<0.05) when compared to LV1-CTRL. Static parameters of bone formation and resorption were augmented in both sites, significantly only in LV1 (p<0.05) with a trend of increases in MS/BS and BFR/BS, compared to LV1-CTRL. In conclusion, in adult ewes, the bone mass, microarchitecture, remodeling and collagen crosslink content differ according to the bone site (iliac crest and vertebra). Furthermore, after 3months, the responses to ZOL and TPTD were of different magnitude and delay between the two bone sites. The distinction of bone sites to study the early effects of anti-osteoporotic therapies appears meaningful in order to approach their site-specific anti-fracture efficacy.

Spinal Cord Ischemia After Endovascular Embolization of a Type II Endoleak Following Endovascular Aneurysm Repair

We report a rare case of severe spinal cord ischemia with neurological consequences in a patient who presented after endovascular treatment of a type II endoleak following endovascular aneurysm repair. An enlarging abdominal aortic aneurysm post-endovascular aneurysm repair was detected owing to a persistent type II endoleak caused by a communication between the iliolumbar and L4 lumbar artery for which the patient underwent supraselective embolization with particles and coils. Immediately after the procedure, the patient experienced an acute onset of neurological symptoms in the right lower limb while limb arterial perfusion remained unaffected. Magnetic resonance imaging-magnetic resonance angiography revealed an acute ischemic process at the L2-L4 level. Further follow-up revealed persistence of the endoleak, and the patient was referred to our institution for open surgical treatment. To the best of our knowledge, this is the first report of severe spinal cord ischemia after transcatheter embolization of the feeding iliolumbar branches of a type II endoleak. Care must be taken during embolization of the feeding artery of type II endoleaks, which may also supply the spinal cord, to minimize the risk of possible spinal cord ischemia.

Complement factor C5a and C5a receptor contribute to morphine tolerance and withdrawal-induced hyperalgesia in rats

Morphine is a potent opioid analgesic. However, the repeated use of morphine causes tolerance and hyperalgesia. Neuroinflammation has been reported to be involved in morphine tolerance and withdrawal-induced hyperalgesia. The complement system is a crucial effector mechanism of immune responses. The present study investigated the roles of complement factor C5a and C5a receptor (C5aR) in the development of morphine tolerance and withdrawal-induced hyperalgesia. In the present study, the levels of C5a and C5aR were increased in the L5 lumbar spinal cords of morphine-tolerant rats. The administration of C5a promoted the development of hyperalgesia and the expression of spinal antinociceptive tolerance to intrathecal morphine in both mechanical and thermal test. However, these phenomena caused by morphine were significantly attenuated by the C5aR antagonist PMX53. These results suggest that complement activation within the spinal cord is involved in morphine tolerance and withdrawal-induced hyperalgesia. C5a and C5aR may serve as novel targets for the control of morphine tolerance and withdrawal-induced hyperalgesia.

Pattern of Porcine Intervertebral Disk by Sensory Innervation-A Preliminary Retrograde Neuronal Tract-Tracing Study

Introduction The problem of intervertebral disk degeneration has been approached from many sides, from orthopedic surgery to molecular biology, and the scientific literature on the subject is particularly diverse. For many intervertebral disk diseases, model system plays an important role in clarifying pathomechanisms and testing novel therapeutic techniques. The goal of this study was to elucidate the detailed origin pattern of sensory nerve fibres within the porcine lumbar intervertebral disk, to provide the basis for further experiments focusing on the physiology, pathophysiology and neurogenically-driven regenerative potential of this organ in a new animal model. Materials and Methods Six juvenile female pigs were injected with 350 µmL of a mixture composed of 30 µmL of 5% aqueous solution of a fluorescent retrograde tracer Fast Blue (FB) and 320 µmL of a radiologic contrasting agent (Omnipaque; 300 mg Iohexolum/mL; Nycomed, Ireland) into the intervertebral disk located between the L4 and L5 lumbar vertebra. The position of the needle was checked radiologically before the deposition of the solution into the pulpous nucleus of the disk under study. After 2 weeks survival period (an optimal time for FB transport to the parent perikarya of nerve terminals supplying the disk) all animals were sacrificed, transcardially perfused with freshly prepared 4% buffered paraformaldehyde and bilateral dorsal root ganglia (DRGs). Th13 to Cq1 were collected, cryoprotected and then sectioned on a cryostat into 10-µmL-thick serial sections. The presence, distribution, and the diameter of retrogradely labelled DRG neurons were investigated under the BX61 fluorescence microscope (Olympus Poland) in each section. Results After application of the tracer into the nucleus pulpous of the L4/L5 intervertebral disk, FB-positive sensory neurons were found in bilateral ThL1-6 DRGs. The average number of FB-positive cells supplying the injected disk yielded approximately 930 cells per animal (ranging from 713 to 1148). The relative frequency of FB-labelled neurons in particular DRGs studied was as follow: L1 0.9%, L2 4.5%, L3-11.5%, L4-63%, L5-11.8, and L6-3.3 (taking all traced neurons found as 100%). Furthermore, it has been found that traced cells belonged to two morphologically distinct classes of DRG neurons: a vast majority of them were small diameter, whereas only few belonged to the class of large-diameter (up to 50µm) neurons. For example, the most of FB + /CGRP + small-size neurons were also immunoreactive to P Conclusion The present study clearly shows that the pattern of porcine intervertebral disk sensory innervation is very complicated and originated from numerous DRGs along the spinal cord. As the present data are preliminary one, and we don't know, as to whether there are any differences in the chemical coding ( = neurotransmitter(s) synthetized and used) of disk-projecting neurons in particular DRGs, it is hard to predict any physiological relevance of the presence of traced sensory cells in such a distant DRG as, Th13 or S2. However, as DRG neurons of different diameter are thought to fulfill different physiological functions, one may suggest that the “small” FB-positive perikarya are involved in conveying nociceptive information from the disk, while the “large” ones are mechanoceptors rather. However, further studies are needed to clarify both the chemical coding of the disk-projecting DRG neurons, as well as to elucidate their physiological relevance for maintaining the disk homeostasis. Moreover, this study provides for the first time data concerning the sources and distribution pattern of sensory neurons supplying an intervertebral disk in the domestic pig, an animal that may be used as a new animal model for studying physiological and pathophysiological processes within this organ. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared

Pattern of Porcine Intervertebral Disk by Sensory Innervation-A Preliminary Retrograde Neuronal Tract-Tracing Study

IntroductionThe problem of intervertebral disk degeneration has been approached from many sides, from orthopedic surgery to molecular biology, and the scientific literature on the subject is particularly diverse. For many intervertebral disk diseases, model system plays an important role in clarifying pathomechanisms and testing novel therapeutic techniques. The goal of this study was to elucidate the detailed origin pattern of sensory nerve fibres within the porcine lumbar intervertebral disk, to provide the basis for further experiments focusing on the physiology, pathophysiology and neurogenically-driven regenerative potential of this organ in a new animal model.Materials and MethodsSix juvenile female pigs were injected with 350 µmL of a mixture composed of 30 µmL of 5% aqueous solution of a fluorescent retrograde tracer Fast Blue (FB) and 320 µmL of a radiologic contrasting agent (Omnipaque; 300 mg Iohexolum/mL; Nycomed, Ireland) into the intervertebral disk located between the L4 and L5 lumbar vertebra. The position of the needle was checked radiologically before the deposition of the solution into the pulpous nucleus of the disk under study. After 2 weeks survival period (an optimal time for FB transport to the parent perikarya of nerve terminals supplying the disk) all animals were sacrificed, transcardially perfused with freshly prepared 4% buffered paraformaldehyde and bilateral dorsal root ganglia (DRGs). Th13 to Cq1 were collected, cryoprotected and then sectioned on a cryostat into 10-µmL-thick serial sections. The presence, distribution, and the diameter of retrogradely labelled DRG neurons were investigated under the BX61 fluorescence microscope (Olympus Poland) in each section.ResultsAfter application of the tracer into the nucleus pulpous of the L4/L5 intervertebral disk, FB-positive sensory neurons were found in bilateral ThL1-6 DRGs. The average number of FB-positive cells supplying the injected disk yielded approximately 930 cells per animal (ranging from 713 to 1148). The relative frequency of FB-labelled neurons in particular DRGs studied was as follow: L1 0.9%, L2 4.5%, L3-11.5%, L4-63%, L5-11.8, and L6-3.3 (taking all traced neurons found as 100%). Furthermore, it has been found that traced cells belonged to two morphologically distinct classes of DRG neurons: a vast majority of them were small diameter, whereas only few belonged to the class of large-diameter (up to 50µm) neurons. For example, the most of FB + /CGRP + small-size neurons were also immunoreactive to PConclusionThe present study clearly shows that the pattern of porcine intervertebral disk sensory innervation is very complicated and originated from numerous DRGs along the spinal cord. As the present data are preliminary one, and we don't know, as to whether there are any differences in the chemical coding ( = neurotransmitter(s) synthetized and used) of disk-projecting neurons in particular DRGs, it is hard to predict any physiological relevance of the presence of traced sensory cells in such a distant DRG as, Th13 or S2. However, as DRG neurons of different diameter are thought to fulfill different physiological functions, one may suggest that the “small” FB-positive perikarya are involved in conveying nociceptive information from the disk, while the “large” ones are mechanoceptors rather. However, further studies are needed to clarify both the chemical coding of the disk-projecting DRG neurons, as well as to elucidate their physiological relevance for maintaining the disk homeostasis. Moreover, this study provides for the first time data concerning the sources and distribution pattern of sensory neurons supplying an intervertebral disk in the domestic pig, an animal that may be used as a new animal model for studying physiological and pathophysiological processes within this organ.I confirm having declared any potential conflict of interest for all authors listed on this abstractYesDisclosure of InterestNone declared

The surgical treatment for a rare case of double-level isthmic spondylolisthesis in L4 and L5 lumbar spine: decompression, reduction and fusion.

An unusual case of a double-level isthmic spondylolisthesis of the lumbar spine in a 38-year-old female was described. The patient had been suffering from low back pain for 8years and did not respond to conservative treatment. Her medical examination revealed that grade II isthmic spondylolisthesis was present both at L-4 to L-5 and at L-5 to S-1. The patient was managed by surgical treatment. After the reduction of lysthesis with posterior instrumentation, posterior lumbar interbody fusion (PLIF) technique was performed for double level. At a recent follow-up, 1year after the surgery, the symptoms of the patient were completely resolved, reduction was preserved, and fusion was achieved. PLIF with posterior instrumentation and reduction seems to be a convenient treatment option in the treatment for double-level spondylolisthesis.

The comparison of the effect of intrathecal levobupivacaine and bupivacaine for ano-rectal surgery

Objectives: Spinal anesthesia is widely used for ano-rectal surgery. We aimed to compare the anesthetic potencies and hemodynamic effects of levobupivacaine and bupivacaine with fentanil intrathecally administered in patients undergoing ano-rectal surgery. Materials and methods: After Dicle University Medical Faculty Research Hospital ethical committee approval and written consent of the patients who underwent anorectal surgery were obtained, sixty patients between the ages of 18-65 with ASA I-II were enrolled in this study. The patients were randomly allocated to two groups; Group I recived 9 mg bupivacaine 0.5% and 20 mcg fentanil (total 2 ml), and Group II received 9 mg levobupivacaine 0.5% and 20 mcg fentanyl (total 2.6 ml). Spinal anesthesia was performed using a 26 G spinal needle via the L4-5 lumbar intervertebral space. Patients’ grade of sensory block was assessed with pin prick test, and the grade of motor block was assessed with bromage scale. Hemodynamic data were also recorded. Results: Two segment regression time and of sensory block onset time are similar between the groups. Motor block onset time was longer in bupivacaine group than levobupivacaine group but motor block regression time was shorter in group levobupivacaine. Hemodynamic parameters were similar in both groups. Conclusions: Our results shows that levobupivacaine which has similar features with bupivacaine in terms of sensory block may be a good alternative to bupivacaine in the operations in which development of the motor blocks is unwanted.

Recombinant receptor activator of nuclear factor κB exhibits more marked inhibitory effects on osteoclasts compared with recombinant osteoprotegerin in vitro and in vivo.

The aim of the present study was to compare the osteoclast-inhibiting ability of recombinant osteoprotegerin (OPG) protein (rhOPG-Fc) and recombinant receptor activator of nuclear factor κB (rhRANK) in vitro and in vivo. Osteoclasts were cultured with either rhOPG-Fc or rhRANK for 9 days. The number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and resorption pits in bone slices were then counted. In the in vivo investigation, female mice were bilaterally ovariectomized (OVX) and intraperitoneally injected with 3 mg/kg rhOPG-Fc or rhRANK for 12 weeks, respectively. Bone metabolism, bone mineral density and microstructure changes were then evaluated. The number of TRAP-positive cells and bone resorption pits decreased significantly following culture with either rhOPG-Fc or rhRANK, and this was more marked following culture with rhRANK compared with rhOPG-Fc. The levels of calcium and alkaline phosphatase in the serum were similar pre-OVX and after 12 weeks of treatment, while the levels of phosphorus in the serum were higher following treatment with rhRANK compared with rhOPG. The bone mineral density (BMD) of the whole body, femoral neck and L4 lumbar vertebral body in the mice treated with either rhOPG-Fc or rhRANK increased markedly. In addition, the mice treated with rhRANK exhibited significantly higher BMD in the femoral neck and lumbar vertebral body compared with those treated with rhOPG-Fc. Microcomputed tomography analysis demonstrated that the mice treated with rhRANK exhibited an increased bone volume and structure model index, and decreased trabecular spacing compared with those treated with rhOPG-Fc. rhRANK increased the inhibition of osteoclast differentiation and bone resorption, and rescued OVX-induced osteoporosis more effectively compared with rhOPG-Fc.

Lipoxin A4 analog attenuates morphine antinociceptive tolerance, withdrawal-induced hyperalgesia, and glial reaction and cytokine expression in the spinal cord of rat

Spinal neuroinflammation has been shown to play an important role in the development of morphine tolerance and morphine withdrawal-induced hyperalgesia. Lipoxins are endogenous lipoxygenase-derived eicosanoids that can function as “braking signals” in inflammation. The present study investigated the effect of 5 (S), 6 (R)-lipoxin A4 methyl ester (LXA4ME), a stable synthetic analog of lipoxin A4, on the expression of antinociceptive tolerance and withdrawal-induced hyperalgesia in chronic morphine-treated rats. Chronic morphine administration through repeated subcutaneous injection induced the development of hyperalgesia and the expression of spinal antinociceptive tolerance to morphine. However, LXA4ME treatment significantly attenuated the development of hyperalgesia and the expression of spinal antinociceptive tolerance to intrathecal morphine in both mechanical and thermal test. Moreover, the administration of LXA4ME during the induction of morphine tolerance inhibited the activation of microglia and astrocytes; reduced the expression of proinflammatory cytokines interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α); upregulated the expression of anti-inflammatory cytokines IL-10 and transforming growth factor-β1 (TGF-β1); and inhibited nuclear factor-kappa B (NF-κB) activation at the L5 lumbar spinal cord. These results suggest that treatment of LXA4ME provides a potential preventative or therapeutic approach for morphine tolerance and associated abnormal pain sensitivity.

The evaluation of lumbosacral dysplasia in young patients with lumbosacral spondylolisthesis: comparison with controls and relationship with the severity of slip

Comparison of lumbosacral dysplasia between normal individuals and patients with low and high grade spondylolisthesis has not been done previously. The objective of this study is to evaluate the relationship between lumbosacral dysplasia and severity of slip in young patients with lumbosacral spondylolisthesis. Postero-anterior and lateral radiographs of 120 normal individuals and 131 patients with developmental spondylolisthesis (91 low and 40 high grades) were reviewed. Quantitative evaluation of lumbosacral dysplasia was done using 6 criteria involving the degree of laminar dysplasia, degree of facet dysplasia, size of L5 transverse processes, L5/S1 disc height, type of sacral doming and L5 lumbar index. Subjects were categorized as having no/low, moderate or severe dysplasia based on the total dysplasia score. Comparisons in total dysplasia score between normal, low grade and high grade groups were performed and the correlation between degree of dysplasia and percentage of slip was assessed. Most normal individuals (88.3%) had no/low dysplasia; most patients with low grade spondylolisthesis (61.5%) had moderate dysplasia, while most patients with high grade spondylolisthesis (72.5%) had severe dysplasia. There was a significant difference in dysplasia between normal individuals and patients with spondylolisthesis. Dysplasia also varied significantly between low and high grade spondylolisthesis. There was a strong positive correlation (r = 0.63) between severity of dysplasia and percentage of slip. There is a significant relationship between the severity of spondylolisthesis and lumbosacral dysplasia, with mainly no/low dysplasia observed in controls and increasing total dysplasia scores in higher grades of spondylolisthesis. In addition, a variable degree of dysplasia was found within groups with low or high grade spondylolisthesis, suggesting that different subgroups of patients exist with regard to dysplasia. Thus the degree of dysplasia varies in spondylolisthesis and it is possible that different grades of dysplasia could relate to different prognoses or outcomes with treatment.

Which to Use to Evaluate Change in BMD at Follow-Up: RMS-SD or RMS-%CV?

There is bias toward the use of root-mean-square standard deviation (RMS-SD) over root-mean-square coefficient of variation (RMS-%CV) to calculate a least significant change (LSC) value that is used to determine if change in bone mineral density (BMD) at follow-up is statistically significant. In part, this bias is based on the assumption that SD is relatively constant over a wide range of BMD as opposed to %CV, which is assumed to increase as BMD decreases. However, evidence to support these assumptions is scant. The purpose of this project was to determine the frequency of discrepancies in interpretation of follow-up data using an LSC based on RMS-SD (LSC-SD) vs RMS-%CV (LSC-%CV). A convenience sample of 100 patients returning for follow-up dual-energy X-ray absorptiometry scans was used to compare the frequency of change in BMD exceeding LSC-SD vs LSC-%CV. Results showed that agreement in exceeding (or not) both LSC-SD and LSC-%CV was 94% for L1–L4 (lumbar spine), femoral neck, and total hip. Disagreements were characterized by BMD changes that usually marginally exceeded either LSC-SD or LSC-%CV but not the other, and they occurred at both high and low absolute BMD. We conclude that significant change in BMD typically exceeds both LSC-SD and LSC-%CV. Thus, there seems to be no basis for the bias in favor of using LSC-SD as long as RMS-SD and RMS-%CV are calculated in the same manner. Furthermore, a criterion that both LSC-SD and LSC-%CV must be exceeded may help avoid overcalling marginal change as being significant, especially at high and low BMD.

A New Expanded Cage Designed for Lumbar Disc Herniation: Finite Element Analysis

Objective. To evaluate biomechanics of the new-designed cage for lumbar interbody fusion by using FEMs analysis.Methods. Five validated finite element models of L4–L5 lumbar segments were established to simulate the intact lumbar segement, lumbar discectomy and lumbar discectomy instrumented posterior lumbar interbody fusion with single three kinds of cage (threaded cage, impacted cage and new expanded cage), and analyzed the biomechanics of these models.Results. The maximum ranges of motion and the maximum stress of facet joint were appeared in discectomy model, and the insertion of cages obviously decreased the range and the maximum stresses in all motions. However, only the ranges in expanded cage model were lower than those in intact model. Conclusions. The new-designed expanded cage resulted in highest stability and lowest stress of facet joint in fusion models.

Role of poly (ADP-ribose) polymerase 1 in spinal cord in a rat model of neuropathic pain

Objective To evaluate the role of poly (ADP-ribose) polymerase 1 (PARP1) in spinal cord in a rat model of neuropathic pain.Methods One hundred and eighty male Wistar rats weighing 180-220 g were randomly divided into 4 groups( n =45 each): sham operation group(group S),neuropathic pain group (group NP),siRNA negative control group (group NS) and PARP1-siRNA group (group PS).Neuropathic pain was produced by L5 spinal nerve ligation (SNL).Viral of PARP1-siRNA or viral of siRNA negative control was injected intrathecally after SNL in groups PS or NS.Mechanical pain threshold was determined at 3,7 and 14 d after SNL.Then the rats were sacrificed and L5 lumbar spinal tissues were removed for determination of coexpression of PARP1 with glial fibrillary acidic protein (GFAP) (by immunohistochemistry double stain),protein expression of PARP1 and GFAP (by Western blot),and mRNA expression of PARP1 and GFAP (by RT-PCR).Results Compared with group S,mechanical pain threshold was significantly decreased and the protein and mRNA expression of GFAP and PARP1 up-regulated in groups NP,NS and PS( P ＜ 0.05).Compared with groups NP and NS,mechanical pain threshold was significantly increased and the protein and mRNA expression of GFAP and PARP1 down-regulated in group PS (P ＜ 0.05).There was no significant difference in above indexes between groups NP and NS(P ＞0.05 ).PARR1 was expressed in the astrocytes in the spinal cord.Conclusion PARP1 is involved in the formation and maintainance of neuropathic pain in rats via activating astrocytes. Key words: ADP-ribose; Neuralgia; Spinal cord

Endometrial stromal sarcoma metastasis to the lumbar spine and sphenoid bone

Endometrial stromal sarcoma (ESS) is typically associated with metastasis to the abdomen, pelvis, and lung. We found three case reports of ESS metastasis to the bone (two to the thoracic spine, and one to the parietal bone). Our objective is to review the literature on ESS spinal and intracranial metastases and, report the first case of ESS metastatic to the lumbar paraspinal region and sphenoid bone. A 53-year-old female with ESS status-post radiation, chemotherapy, and pelvic exenteration surgery presented with right hip weakness, back pain, and radicular leg pain that were explained by chemotherapy-induced neuropathy, radiation-induced lumbosacral plexopathy, and femoral nerve and obturator nerve injury during pelvic exenteration surgery. During routine positron emission tomography, we found metastasis to the L3 lumbar spinal region. L3 laminectomy and subtotal resection of the mass was performed with tumor residual in the neuroforamina and pedicles. One month later, magnetic resonance imaging (MRI) performed for persistent headaches revealed a large lesion in the sphenoid bone that was biopsied transsphenoidally with the same diagnosis, but no further surgery was performed. She is intolerant of chemotherapy and currently undergoing whole brain radiation. Delay in the diagnosis and management of lumbar paraspinal and sphenoid bone metastasis of ESS likely occurred because of the uniqueness of the location and aggressiveness of ESS metastasis. Health care providers should be aware of potentially aggressive metastasis of ESS to bone, in particular the unusual locations of the lumbar paraspinal region and sphenoid bone.

Initiation of segmental locomotor-like activities by stimulation of ventrolateral funiculus in the neonatal rat

Descending control is critically important for the generation of locomotor activities. Yet, our understanding of the descending control system of locomotion is limited. We hypothesized that stimulation of the ventrolateral funiculus (VLF) induces rhythmic activity in lumbar neurons that is correlated with locomotor-like activity in the neonatal rat. Intracellular recordings were conducted in the L2-L3 lumbar segments, while locomotor-like output was monitored in the L2 and L5 ventral roots. Stimulation of the VLF at thoracic segments induced locomotor-like activity in the L2 and L5 ventral roots in majority of the preparations (26/33). In a few midline split cord preparations (4/13), VLF stimulation induced rhythmic locomotor-like bursts in either L2 or L5 ventral root without alternating pattern between the ventral roots. The response latencies suggest that VLF stimulation induced antidromic activation (<1ms, 8 cells), monosynaptic activation (1-3ms, 18 cells), and oligosynaptic activation (3.5-5ms, 14 cells) of segmental neurons in the lumbar region. VLF stimulation induced rhythmic membrane potential oscillations with or without bursting of action potentials in 9 of 40 putative interneurons. The membrane potential oscillations were in phase with the locomotor-like output of the L2 ventral root in 7 of the 9 cells while the other 2 cells oscillated in phase with the L5 ventral root activity. We have thus demonstrated that descending axons exist in the VLF which make synaptic connections with segmental neurons in the lumbar region that may be a critical element of the locomotor neural network for the initiation of locomotion.

Sacro-lumbar Intersegmental Spinal Reflex in Autonomic Pathways Mediating Female Sexual Function

Autonomic neurons in paracervical ganglia mediating vasodilation in the female reproductive tract receive inputs from both midlumbar and sacral spinal levels. However, it is not known how the lumbar pathways are activated. This study tested whether stimulation of pudendal sensory nerve could activate lumbar spinal outflows to paracervical ganglia via a spinal reflex pathway. Isolated spinal cords with attached peripheral nerves were removed from urethane-anesthetized female guinea pigs and perfused via the aorta with physiological salt solution. Spinal pathways to midlumbar preganglionic neurons were tested by recording extracellular compound action potentials (CAPs) in lumbar splanchnic or distal hypogastric nerves after electrical stimulation of thoracic spinal cord or the pudendal nerve. CAPs also were recorded from pelvic nerves after pudendal nerve stimulation. Sensory neurons were retrogradely traced from the pudendal nerve and characterized immunohistochemically. Activation of preganglionic neurons projecting from midlumbar spinal cord to paracervical ganglia following stimulation of pudendal sensory nerves in isolated preparations. Thoracic spinal cord stimulation produced CAPs in hypogastric nerves that were abolished by transection of L3 lumbar splanchnic nerves. Pudendal nerve stimulation produced CAPs in L3 lumbar splanchnic, hypogastric, and pelvic nerves, demonstrating an ascending intersegmental spinal circuit to midlumbar levels in addition to the sacral spinal circuit. These CAPs in hypogastric nerves were enhanced by bicuculline (10 µM), blocked by tetrodotoxin (1 µM) but were not affected by hexamethonium (200 µM). Retrograde axonal tracing revealed four groups of sensory neurons in S3 dorsal root ganglia that were distinguished immunohistochemically. Midlumbar preganglionic neurons projecting to paracervical ganglia regulating blood flow and motility in the female reproductive tract can be activated by an ascending intersegmental spinal pathway from pudendal sacral inputs, which is inhibited by local spinal circuits. This pathway will help understand pathological conditions affecting reproductive function.

Finite Element Lumbar Spine Facet Contact Parameter Predictions are Affected by the Cartilage Thickness Distribution and Initial Joint Gap Size

Current finite element modeling techniques utilize geometrically inaccurate cartilage distribution representations in the lumbar spine. We hypothesize that this shortcoming severely limits the predictive fidelity of these simulations. Specifically, it is unclear how these anatomically inaccurate cartilage representations alter range of motion and facet contact predictions. In the current study, cadaveric vertebrae were serially sectioned, and images were taken of each slice in order to identify the osteochondral interface and the articulating surface. A series of custom-written algorithms were utilized in order to quantify each facet joint's three-dimensional cartilage distribution using a previously developed methodology. These vertebrae-dependent thickness cartilage distributions were implemented on an L1 through L5 lumbar spine finite element model. Moments were applied in three principal planes of motion, and range of motion and facet contact predictions from the variable thickness and constant thickness distribution models were determined. Initial facet gap thickness dimensions were also parameterized. The data indicate that the mean and maximum cartilage thickness increased inferiorly from L1 to L5, with an overall mean thickness value of 0.57 mm. Cartilage distribution and initial facet joint gap thickness had little influence on the lumbar range of motion in any direction, whereas the mean contact pressure, total contact force, and total contact area predictions were altered considerably. The data indicate that range of motion predictions alone are insufficient to establish model validation intended to predict mechanical contact parameters. These data also emphasize the need for the careful consideration of the initial facet joint gap thickness with respect to the spinal condition being studied.