Pathology of lumbar nerve root compression. Part 2: morphological and immunohistochemical changes of dorsal root ganglion

The effect of dietary sesame oil and ginger oil as antioxidants in the adult rat dorsal root ganglia after peripheral nerve crush injury

AIM

The purpose of this study was to investigate the effect of dietary sesame oil and ginger oil supplements on the dorsal root ganglia following a sciatic nerve crush model in male Wistar albino rats.

MATERIALS AND METHODS

Crush injury models have been done by means of graded forceps (50 Newton). The animals were given a daily sesame oil (4 ml/kg/day) and ginger oil (400 mg/kg/day) via oral gavage for a period of 28 days. Dorsal root ganglia from the L5 levels were harvested. Processing of tissues was done for electron microscopy and light microscopy. Immunohistochemical staining with active caspase-3 antibody and qualitative ultrastructural analyses of tissues were made by a light and a transmission electron microscope, respectively.

RESULTS

The results showed that crush injury leads to remarkable ultrastructural changes in sensory neurons, such as swollen mitochondria, disruption of cristae structure, glial cell proliferation and, consequently, phagocytosis of the damaged neuron. These ultrastructural changes were less evident in the treated groups, and both natural compounds reduced the expression of activated caspase-3, which may also affect ultrastructural changes.

CONCLUSION

The application of the natural products sesame oil and ginger oil may represent a supportive approach to the protection of sensory neurons against the destructive effects of peripheral nerve crush injury.

Lumbar safety triangle: comparative study of coronal and coronal oblique planes in 3.0-T magnetic resonance imaging

Objective

To compare the measurements of the lumbar safety triangle (Kambin's triangle) and the invasion of the dorsal root ganglion in the triangle in coronal and coronal oblique planes.

Materials and Methods

A cross-sectional study, in which 210 3.0-T magnetic resonance images of L2-L5 were analyzed in coronal and coronal oblique planes. Exams with lumbar spine anomalies were excluded. Demographic (sex and age) and radiological variables were recorded by a single evaluator.

Results

Most sample was female (57.1%), mean age 45.5 ± 13.3 (18-98 years). The measurements average, as well as the areas, gradually increased from L2 to L5. The dorsal root ganglion invaded the triangle in all images. The safety triangle average area was smaller in the coronal oblique plane than in the coronal plane. Of the seven dimensions of safety triangle obtained for each level of the lumbar spine, six were significantly smaller in the coronal oblique plane than in the coronal plane. The only dimension that showed no difference was the smallest ganglion dimension.

Conclusion

The dimensions and areas investigated were smaller in coronal oblique plane, especially the area (difference > 1 mm). The analysis of the triangular zone in this plane becomes important in the preoperative assessment of minimally invasive procedures.

Effect of concurrent aerobic exercise and bone marrow stromal cell transplantation on time-dependent changes of myogenic differentiation-related cascades in soleus muscle after sciatic nerve injury

The purpose of this study was to investigate the time-dependent alteration in whether concurrent aerobic exercise and bone marrow stromal cell (BMSC) engraftment could regulate myogenic differentiation-related signaling pathway in the soleus up to 35 days after sciatic nerve injury (SNI). The rats were divided as follows: the normal control (CON, n=5), sedentary group (SED, n=20), treadmill exercise group (TEX, n=20), BMSC transplantation group (BMSC, n=20), TEX+BMSC transplantation group (TEX+BMSC, n=20) 7, 14, 21, and 35 days after SNI. SNI was applied into the thigh and treadmill exercise was comprised of walking at a speed of 4 to 8 m/min for 30 min once a day. Harvested BMSC at a density of 5×10⁶ in 50-μL phosphate-buff-ered saline was injected into the injury site. Phosphorylated (p) extracellular signal-regulated kinase 1/2 expression was dramatically upregulated in BMSC and BMSC+EX groups from 21 days after SNI compared to those in the SED group. P-ribosomal s6 kinase (RSK) was sharply increased 14 days later, and then rapidly downregulated from day 21, whereas TEX, BMSC and TEX+ BMSC groups significantly kept up expression levels of p-RSK until 35 days post injury than SED group. TEX+BMSC group significantly increased activation of protein kinase B-mammalian target of rapamycin in the soleus from day 14 and myoblast determination protein 1-myogen-in pathways was activated in TEX+BMSC group from day 21. Present findings provide information that combined intervention of aerobic exercise and BMSC transplantation might be a reliable therapeutic strategy for overcoming the morphological and functional problems in denervated soleus muscle.

Effect of simultaneous application of positional release technique and Maitland mobilization technique on sciatica: a randomized controlled trial

Background

Low back pain (LBP) associated with sciatica is considered the primary cause of seeking medical and physical therapy advice. Treating sciatica symptoms is the main goal in the physical therapy practice, and the literature supports the use of manual therapy techniques in management of patients with sciatica.

Objectives

This study aimed to assess the effect of simultaneous application of positional release technique and grade-4 Maitland mobilization technique on sciatic nerve sensory nerve conduction velocity (NCV) in patients with LBP associated with sciatica.

Methods

A randomized controlled trial was performed among 50 patients (mean age 41.86 ± 7.90) diagnosed with LBP with sciatica. Patients were randomly assigned to two groups: experimental “group A, n = 25” and control “group B, n = 25.” Patients were tested twice, before and after a 6-week period, during which group A received a traditional physical therapy program along with piriformis muscle positional release technique and grade-4 Maitland mobilization technique, while group B received a traditional physical therapy program along with a sham mobilization technique.

Results

Statistical analysis revealed a significant increase (p < 0.05) in the sciatic nerve sensory NCV in the post-test condition compared with the pre-test in group A with no significant difference (p > 0.05) in group B.

Conclusion

Simultaneous application of the piriformis muscle positional release technique and grade-4 Maitland mobilization technique on lower lumbar spine may improve sciatic nerve function in patients with LBP associated with sciatica.

Resistance exercise promotes functional test via sciatic nerve regeneration, and muscle atrophy improvement through GAP-43 regulation in animal model of traumatic nerve injuries

Resistance training improves muscle strength through a combination of neural plasticity and muscle hypertrophy. This study aimed to evaluate the effects of resistance exercise on sciatic nerve regeneration and histology, growth-associated protein 43 (GAP-43) expressions, and soleus muscle atrophy following traumatic nerve injuries in Wistar rats. In the present study, 40 male Wistar rats were randomly assigned into four groups: healthy control (HC) as a sham group was exposed to the surgical procedures without any sciatic nerve compression, lesioned control (LC), resistance training (RT,non-lesioned), and lesioned rats+RT (LRT) (n=10 in each). The RT group performed a resistance-training program 5 days/week for 4 weeks. Sciatic functional index (SFI) score, beam score and Basso, Beattie, and Bresnahan (BBB) score decreased and the hot plate time increased significantly in the LC‌ group compared to the HC (p<0.05) group. However, the LRT‌ group showed a significant increase in the SFI score (p=0.001) and a significant decrease in hot plate time (p=0.0232) compared to the LC group. The LC group also showed neurological morphological damage and muscle atrophy and a decrease in GAP-43 in nerve tissue. In comparison to the LC group, a significant increase in sciatic nerve caliber, diameter, number of muscle fibers, and the expression of GAP-43‌ (p<0.05) was observed in the LRT group. Doing resistance training even for four weeks seems to affect sciatic nerve lesions and injuries. It can also repair and regenerate nerve tissue by upregulating GAP-43 expression‌, improving motor behavioral tests, and controlling muscle atrophy.

Mechanisms of bone pain: Progress in research from bench to bedside

The field of research on pain originating from various bone diseases is expanding rapidly, with new mechanisms and targets asserting both peripheral and central sites of action. The scope of research is broadening from bone biology to neuroscience, neuroendocrinology, and immunology. In particular, the roles of primary sensory neurons and non-neuronal cells in the peripheral tissues as important targets for bone pain treatment are under extensive investigation in both pre-clinical and clinical settings. An understanding of the peripheral mechanisms underlying pain conditions associated with various bone diseases will aid in the appropriate application and development of optimal strategies for not only managing bone pain symptoms but also improving bone repairing and remodeling, which potentially cures the underlying etiology for long-term functional recovery. In this review, we focus on advances in important preclinical studies of significant bone pain conditions in the past 5 years that indicated new peripheral neuronal and non-neuronal mechanisms, novel targets for potential clinical interventions, and future directions of research.

[Neurogenic intermittent claudication in patients with degenerative lumbar stenosis]

OBJECTIVE

To study the clinical manifestations of neurogenic intermittent claudication (NIC) in patients with degenerative lumbar stenosis (DLS).

MATERIAL AND METHODS

The neurological status, intensity and nature of pain syndrome, and pain-free walking distance were evaluated in 83 NIC patients with DPS, who underwent surgical treatment.

RESULTS

The predominance of the clinical picture of sensorimotor pain (n=30; 36.1%) and isolated pain (n=31; 37.3%) forms of NIC was established. Isolated sensory (n=1; 1.2%), sensorimotor (n=3; 3.6%), and motor-pain (n=4; 4.8%) forms were significantly less common. In 6 (7.2%) patients, there was a pain-free form of NIC. In most patients, surgical treatment led to regression of neurological symptoms and an increase in the distance of pain-free walking. No relationship was found between the demographic and clinical characteristics of patients (gender, age, pain severity, pain-free walking distance), MRI results and the features of NIC clinical picture. In 4 patients, the phenomenon of pacing was revealed in the form of an increase in pain at the beginning of walking and a significant decrease or complete regression as walking continues.

CONCLUSION

The clinical picture of NIC is polymorphic, its pain-free course is possible. The decision on the feasibility of surgical treatment of patients with PLS is possible taking into account the clinical picture of NIC and MRI results.

Can Foraminal Stenosis Due to Lumbar Isthmic Spondylolisthesis Cause Axonopathy in the Lower Extremity?

This study aimed to investigate, using electrodiagnosis, whether foraminal stenosis due to isthmic spondylolisthesis (IS) causes peripheral nerve axonopathy. We retrospectively reviewed the medical records of the Yeungnam University Hospital and included 46 patients (mean age = 60.8 ± 13.7 years; male:female = 24:22) with foraminal stenosis due to IS. We classified foraminal stenosis grading based on T2 and T1 sagittal spinal magnetic resonance imaging (MRI). Patients were divided into mild (n = 18) and severe foraminal stenosis (n = 28) groups. To evaluate axonopathy in the lower extremity, results of compound motor action potential (CMAP) of the extensor digitorum brevis muscle (EDB) and abductor hallucis brevis muscle (AHB), and sensory nerve action potential (SNAP) of the sural nerve were retrieved. No statistically significant difference was observed in the amplitude of CMAP of the EDB and AHB and SNAP of the sural nerve with the severity of foraminal stenosis. However, age showed a statistically significant relationship with the amplitude of NCS in the EDB, AHB, and sural nerves (p < 0.001). The severity of foraminal stenosis due to IS showed no relationship with axonopathy beyond age-related degeneration of the lower extremities. Therefore, if there is robust axonopathy in lower extremities, physicians should consider pathologies other than foraminal stenosis due to IS.

The impact of increasing interbody fusion levels at the fractional curve on lordosis, curve correction, and complications in adult patients with scoliosis

OBJECTIVE

Radiculopathy from the fractional curve, usually from L3 to S1, can create severe disability. However, treatment methods of the curve vary. The authors evaluated the effect of adding more levels of interbody fusion during treatment of the fractional curve.

METHODS

A single-institution retrospective review of adult patients treated for scoliosis between 2006 and 2016 was performed. Inclusion criteria were as follows: fractional curves from L3 to S1 > 10°, ipsilateral radicular symptoms concordant on the fractional curve concavity side, patients who underwent at least 1 interbody fusion at the level of the fractional curve, and a minimum 1-year follow-up. Primary outcomes included changes in fractional curve correction, lumbar lordosis change, pelvic incidence - lumbar lordosis mismatch change, scoliosis major curve correction, and rates of revision surgery and postoperative complications. Secondary analysis compared the same outcomes among patients undergoing posterior, anterior, and lateral approaches for their interbody fusion.

RESULTS

A total of 78 patients were included. There were no significant differences in age, sex, BMI, prior surgery, fractional curve degree, pelvic tilt, pelvic incidence, pelvic incidence - lumbar lordosis mismatch, sagittal vertical axis, coronal balance, scoliotic curve magnitude, proportion of patients undergoing an osteotomy, or average number of levels fused among the groups. The mean follow-up was 35.8 months (range 12-150 months). Patients undergoing more levels of interbody fusion had more fractional curve correction (7.4° vs 12.3° vs 12.1° for 1, 2, and 3 levels; p = 0.009); greater increase in lumbar lordosis (-1.8° vs 6.2° vs 13.7°, p = 0.003); and more scoliosis major curve correction (13.0° vs 13.7° vs 24.4°, p = 0.01). There were no statistically significant differences among the groups with regard to postoperative complications (overall rate 47.4%, p = 0.85) or need for revision surgery (overall rate 30.7%, p = 0.25). In the secondary analysis, patients undergoing anterior lumbar interbody fusion (ALIF) had a greater increase in lumbar lordosis (9.1° vs -0.87° for ALIF vs transforaminal lumbar interbody fusion [TLIF], p = 0.028), but also higher revision surgery rates unrelated to adjacent-segment pathology (25% vs 4.3%, p = 0.046). Higher ALIF revision surgery rates were driven by rod fracture in the majority (55%) of cases.

CONCLUSIONS

More levels of interbody fusion resulted in increased lordosis, scoliosis curve correction, and fractional curve correction. However, additional levels of interbody fusion up to 3 levels did not result in more postoperative complications or morbidity. ALIF resulted in a greater lumbar lordosis increase than TLIF, but ALIF had higher revision surgery rates.

Effects of neural mobilization in patients after lumbar microdiscectomy due to intervertebral disc lesion

BACKGROUND

Neural mobilization (NM) techniques have been shown to improve the neural tissue's viscoelastic properties that may lead to recover of the function of the nerve after lumbar spine surgery. This study aimed to determine the effects of NM in addition to standard rehabilitation on lumbar and sciatic pain intensity, disability level, and quality of life in patients after receiving a microdiscectomy of the intervertebral lumbar disc (IVD).

METHODS

Twenty-four participants (age 41.3 ± 8.3 years old) within 3-4 weeks of a microdiscectomy of an IVD were randomly allocated to control (CTRL; n = 12) or NM group (n = 12). The CTRL group received ten standard rehabilitation sessions. The NM group received the same rehabilitation sessions with the addition of NM techniques. The intensity of lumbar and sciatic pain (visual analogue scale), disability level (Oswestry disability index), and health-related quality of life (SF-36 questionnaire) were measured before and after the intervention.

RESULTS

Within-group analysis revealed a significant reduction in lumbar (p < 0.05) and sciatic pain intensity (p < 0.001), disability level (p < 0.001), and improvement in the physical function and problems, vitality, emotional well-being, and pain SF-36 items (p < 0.05) in both groups. There were no statistical differences between groups in all outcomes.

CONCLUSION

A standard rehabilitation protocol alone or in combination with NM techniques are equally effective in reducing pain and disability level, as well as improving quality of life in patients after a microdiscectomy due to intervertebral lumbar disc lesion.

The effect of needle tip position on the analgesic efficacy of pulsed radiofrequency treatment in patients with chronic lumbar radicular pain: a retrospective observational study

Background

Pulsed radiofrequency (PRF) is a treatment modality that alleviates radicular pain by intermittently applying high-frequency currents adjacent to the dorsal root ganglion. There has been no comparative study on analgesic effect according to the position of the needle tip in PRF treatment. The objective of this study is to evaluate the clinical outcomes of PRF according to the needle tip position.

Methods

Patients were classified into 2 groups (group IP [group inside of pedicle] and group OP [group outside of pedicle]) based on needle tip position in the anteroposterior view of fluoroscopy. In the anteroposterior view, the needle tip was advanced medially further than the lateral aspect of the corresponding pedicle in group IP; however, in group OP, the needle tip was not advanced. The treatment outcomes and pain scores were evaluated at 4, 8, and 12 weeks after applying PRF.

Results

At 4, 8, and 12 weeks, there were no significant differences between the successful response rate and numerical rating scale score ratio.

Conclusions

The analgesic efficacy of PRF treatment did not differ with the needle tip position.

Role of MHC-I Expression on Spinal Motoneuron Survival and Glial Reactions Following Ventral Root Crush in Mice

Lesions to the CNS/PNS interface are especially severe, leading to elevated neuronal degeneration. In the present work, we establish the ventral root crush model for mice, and demonstrate the potential of such an approach, by analyzing injury evoked motoneuron loss, changes of synaptic coverage and concomitant glial responses in β2-microglobulin knockout mice (β2m KO). Young adult (8-12 weeks old) C57BL/6J (WT) and β2m KO mice were submitted to a L4-L6 ventral roots crush. Neuronal survival revealed a time-dependent motoneuron-like cell loss, both in WT and β2m KO mice. Along with neuronal loss, astrogliosis increased in WT mice, which was not observed in β2m KO mice. Microglial responses were more pronounced during the acute phase after lesion and decreased over time, in WT and KO mice. At 7 days after lesion β2m KO mice showed stronger Iba-1+ cell reaction. The synaptic inputs were reduced over time, but in β2m KO, the synaptic loss was more prominent between 7 and 28 days after lesion. Taken together, the results herein demonstrate that ventral root crushing in mice provides robust data regarding neuronal loss and glial reaction. The retrograde reactions after injury were altered in the absence of functional MHC-I surface expression.

Treatment of only the fractional curve for radiculopathy in adult scoliosis: comparison to lower thoracic and upper thoracic fusions

OBJECTIVE

Many options exist for the surgical management of adult spinal deformity. Radiculopathy and lumbosacral pain from the fractional curve (FC), typically from L4 to S1, is frequently a reason for scoliosis patients to pursue surgical intervention. The purpose of this study was to evaluate the outcomes of limited fusion of the FC only versus treatment of the entire deformity with long fusions.

METHODS

All adult scoliosis patients treated at the authors' institution in the period from 2006 to 2016 were retrospectively analyzed. Patients with FCs from L4 to S1 > 10° and radiculopathy ipsilateral to the concavity of the FC were eligible for study inclusion and had undergone three categories of surgery: 1) FC only (FC group), 2) lower thoracic to sacrum (LT group), or 3) upper thoracic to sacrum (UT group). Primary outcomes were the rates of revision surgery and complications. Secondary outcomes were estimated blood loss, length of hospital stay, and discharge destination. Spinopelvic parameters were measured, and patients were stratified accordingly.

RESULTS

Of the 99 patients eligible for inclusion in the study, 27 were in the FC group, 46 in the LT group, and 26 in the UT group. There were no significant preoperative differences in age, sex, smoking status, prior operation, FC magnitude, pelvic tilt (PT), sagittal vertical axis (SVA), coronal balance, pelvic incidence-lumbar lordosis (PI-LL) mismatch, or proportion of well-aligned spines (SVA < 5 cm, PI-LL mismatch < 10°, and PT < 20°) among the three treatment groups. Mean follow-up was 30 (range 12-112) months, with a minimum 1-year follow-up. The FC group had a lower medical complication rate (22% [FC] vs 57% [LT] vs 58% [UT], p = 0.009) but a higher rate of extension surgery (26% [FC] vs 13% [LT] vs 4% [UT], p = 0.068). The respective average estimated blood loss (592 vs 1950 vs 2634 ml, p < 0.001), length of hospital stay (5.5 vs 8.3 vs 8.3 days, p < 0.001), and rate of discharge to acute rehabilitation (30% vs 46% vs 85%, p < 0.001) were all lower for FC and highest for UT.

CONCLUSIONS

Treatment of the FC only is associated with a lower complication rate, shorter hospital stay, and less blood loss than complete scoliosis treatment. However, there is a higher associated rate of extension of the construct to the lower or upper thoracic levels, and patients should be counseled when considering their options.

Physiologic facet capsule stretch can induce pain & upregulate matrix metalloproteinase-3 in the dorsal root ganglia when preceded by a physiological mechanical or nonpainful chemical exposure

BACKGROUND

Neck pain from cervical facet loading is common and induces inflammation and upregulation of nerve growth factor (NGF) that can sensitize the joint afferents. Yet, the mechanisms by which these occur and whether afferents can be pre-conditioned by certain nonpainful stimuli are unknown. This study tested the hypothesis that a nonpainful mechanical or chemical insult predisposes a facet joint to generate pain after a later exposure to typically nonpainful distraction.

METHODS

Rats were exposed to either a nonpainful distraction or an intra-articular subthreshold dose of NGF followed by a nonpainful distraction two days later. Mechanical hyperalgesia was measured daily and C6 dorsal root ganglia (DRG) tissue was assayed for NGF and matrix metalloproteinase-3 (MMP-3) expression on day 7.

FINDINGS

The second distraction increased joint displacement and strains compared to its first application (p = 0.0011). None of the initial exposures altered behavioral sensitivity in either of the groups being pre-conditioned or in controls; but, sensitivity was established in both groups receiving a second distraction within one day that lasted until day 7 (p < 0.024). NGF expression in the DRG was increased in both groups undergoing a pre-conditioning exposure (p < 0.0232). Similar findings were observed for MMP-3 expression, with a pre-conditioning exposure increasing levels after an otherwise nonpainful facet distraction.

INTERPRETATION

These findings suggest that nonpainful insults to the facet joint, when combined, can generate painful outcomes, possibly mediated by upregulation of MMP-3 and mature NGF.

Treatment of the Fractional Curve of Adult Scoliosis With Circumferential Minimally Invasive Surgery Versus Traditional, Open Surgery: An Analysis of Surgical Outcomes

STUDY DESIGN

Retrospective, multicenter review of adult scoliosis patients with minimum 2-year follow-up.

OBJECTIVE

Because the fractional curve (FC) of adult scoliosis can cause radiculopathy, we evaluated patients treated with either circumferential minimally invasive surgery (cMIS) or open surgery.

METHODS

A multicenter retrospective adult deformity review was performed. Patients included: age >18 years with FC >10°, ≥3 levels of instrumentation, 2-year follow-up, and one of the following: coronal Cobb angle (CCA) > 20°, pelvic incidence and lumbar lordosis (PI-LL) > 10°, pelvic tilt (PT) > 20°, and sagittal vertical axis (SVA) > 5 cm.

RESULTS

The FC was treated in 118 patients, 79 open and 39 cMIS. The FCs had similar coronal Cobb angles preoperative (17° cMIS, 19.6° open) and postoperative (7° cMIS, 8.1° open), but open had more levels treated (12.1 vs 5.7). cMIS patients had greater reduction in VAS leg (6.4 to 1.8) than open (4.3 to 2.5). With propensity matching 40 patients for levels treated (cMIS: 6.6 levels, N = 20; open: 7.3 levels, N = 20), both groups had similar FC correction (18° in both preoperative, 6.9° in cMIS and 8.5° postoperative). Open had more posterior decompressions (80% vs 22.2%, P < .001). Both groups had similar preoperative (Visual Analogue Scale [VAS] leg 6.1 cMIS and 5.4 open) and postoperative (VAS leg 1.6 cMIS and 3.1 open) leg pain. All cMIS patients had interbody grafts; 35% of open did. There was no difference in change of primary CCA, PI-LL, LL, Oswestry Disability Index, or VAS Back.

CONCLUSION

Patients' FCs treated with cMIS had comparable reduction of leg pain compared with those treated with open surgery, despite significantly fewer cMIS patients undergoing direct decompression.

Wireless high-frequency dorsal root ganglion stimulation for chronic low back pain: A pilot study

OBJECTIVE

Evaluation of the efficacy of a wireless high-frequency stimulator placed over selected DRG of exiting nerve roots for the treatment of chronic low back pain.

DESIGN

Feasibility.

SUBJECTS

Six subjects with chronic, intractable back pain refractory to standard medical treatment.

METHODS

Four stimulators (Freedom-4A) provided by Stimwave Technologies, were implanted over the DRG exiting nerve roots, bilaterally at both the T9 and L2 vertebral levels. Subjects were asked to evaluate stimulation independently with the devices turned on at T9 and subsequently L2 for each of 2 weeks. Subjects were then monitored for 8 weeks with the preferred stimulator. Pain reduction with the Visual Analog Scale (VAS), functionality with the Oswestry Disability Index (ODI), Patient Global Impression of Change (PGIC) and medication usage were evaluated.

RESULTS

Four subjects preferred T9 stimulation with only one subject preferring stimulation at L2. One subject dropped out of the study before conclusion of the 4-week evaluation and is not included in this report. Average pain levels (n = 5) at 12-week post-implantation decreased with 61% for back pain and 56% for leg pain with a significant reduction in pain medication, including a 100% reduction in opioid pain medications. The average reduction in disability was 12%. Subjects reported an average impression of change of 6 (1 = no change, 7 = great deal better).

CONCLUSIONS

Wireless high-frequency stimulation of the DRG is a viable option to treat chronic low back pain. Preliminary results show a subject preference for stimulation at the T9 vertebral level.

Chromatolysis: Do injured axons regenerate poorly when ribonucleases attack rough endoplasmic reticulum, ribosomes and RNA?

After axonal injury, chromatolysis (fragmentation of Nissl substance) can occur in the soma. Electron microscopy shows that chromatolysis involves fission of the rough endoplasmic reticulum. In CNS neurons (which do not regenerate axons back to their original targets) or in motor neurons or dorsal root ganglion neurons denied axon regeneration (e.g., by transection and ligation), chromatolysis is often accompanied by degranulation (loss of ribosomes from rough endoplasmic reticulum), disaggregation of polyribosomes and degradation of monoribosomes into dust‐like particles. Ribosomes and rough endoplasmic reticulum may also be degraded in autophagic vacuoles by ribophagy and reticulophagy, respectively. In other words, chromatolysis is disruption of parts of the protein synthesis infrastructure. Whereas some neurons may show transient or no chromatolysis, severely injured neurons can remain chromatolytic and never again synthesize normal levels of protein; some may atrophy or die. Ribonuclease(s) might cause the following features of chromatolysis: fragmentation and degranulation of rough endoplasmic reticulum, disaggregation of polyribosomes and degradation of monoribosomes. For example, ribonucleases in the EndoU/PP11 family can modify rough endoplasmic reticulum; many ribonucleases can degrade mRNA causing polyribosomes to unchain and disperse, and they can disassemble monoribosomes; Ribonuclease 5 can control rRNA synthesis and degrade tRNA; Ribonuclease T2 can degrade ribosomes, endoplasmic reticulum and RNA within autophagic vacuoles; and Ribonuclease IRE1α acts as a stress sensor within the endoplasmic reticulum. Regeneration might be improved after axonal injury by protecting the protein synthesis machinery from catabolism; targeting ribonucleases using inhibitors can enhance neurite outgrowth and could be a profitable strategy in vivo. © 2018 Wiley Periodicals, Inc. Develop Neurobiol, 2018

Sericin and swimming on histomorphometric parameters of denervated plantar muscle in Wistar rats

Objective

To analyze the combined effects of the silk protein sericin and swimming exercise on histomorphometry of the plantar muscle in Wistar rats.

Methods

Forty adult rats were randomly allocated into 5 groups comprising 8 animals each, as follows: Control, Injury, Sericin, Swim, and Swim plus Sericin. Three days after crushing of the sciatic nerve the rats in the Swim and Swim plus Sericin Groups were submitted to swimming exercise for 21 days. Rats were then euthanized and the plantar muscle harvested and processed.

Results

Cross-sectional area, peripheral nuclei and muscle fiber counts, nucleus/fiber ratio and smallest muscle fiber width did not differ significantly between groups. Morphological analysis revealed hypertrophic fibers in the Swim Group and evident muscle damage in the Swim plus Sericin and Injury Groups. The percentage of intramuscular collagen was apparently maintained in the Swim Group compared to remaining groups.

Conclusion

Combined treatment with sericin and swimming exercise did not improve muscle properties. However, physical exercise alone was effective in maintaining intramuscular connective tissue and preventing progression of deleterious effects of peripheral nerve injury.

The treatment effect of hamstring stretching and nerve mobilization for patients with radicular lower back pain

[Purpose] In this paper, hamstring stretching and nerve mobilization are conducted on patients with radicular lower back pain, and changes to pain levels, pressure thresholds, angles of knee joint extension, and disorder levels of lower back pain were studied. [Subjects and Methods] The subjects were divided into two groups: one group conducted hamstring stretches and was comprised of 6 male and 5 female subjects, and the other group received nerve mobilization treatment and was comprised of 5 male and 6 female subjects. [Results] Pain level and the disorder index of lower back pain were significantly alleviated after the intervention in both groups. Pressure threshold and angles of knee extension were significantly increased after the intervention in both groups. Comparing the two groups, the alleviation of pain was more significant in the nerve mobilization group. [Conclusion] Patients with radicular lower back pain showed significant differences in pain level, pressure threshold, knee extension angle, and disorder index of lower back pain for both the hamstring stretching group and nerve mobilization group after the treatment. Hamstring stretching and nerve mobilization can be usefully applied for the therapy of patients with radicular lower back pain.

Relevant Anatomy, Morphology, and Implantation Techniques of the Dorsal Root Ganglia at the Lumbar Levels

OBJECTIVES

While dorsal root ganglion (DRG) stimulation has been available in Europe and Australia for the past five years and in the United States for the past year, there are no published details concerning the optimal procedures for DRG lead implantation.

MATERIALS AND METHODS

We describe several techniques that can be applied to implant cylindrical leads over the DRG, highlighting some tips and tricks according to our experiences. Focus is mainly shifted toward implantations in the lumbar area. We furthermore give some insights in the results we experienced in Spain as well as some worldwide numbers.

IMPLANT TECHNIQUES AND RESULTS

A 14-gauge needle is placed using a "2-Level Technique (2-LT)" or exceptionally a "1-Level Technique (1-LT)" or a "Primary- or Secondary Technique" at the level of L5. The delivery sheath, loaded with the lead, is advanced toward the targeted neural foramen. The lead is placed over the dorsal aspect of the DRG. A strain relief loop is created in the epidural space. Sheath and needle are retracted and the lead is secured using an anchor or anchorless technique. In Spain, 87.2% (N = 78) of the selected patients have been successfully implanted. Seven (8.9%) had a negative trial and three (4.2%) were explanted. Average VAS score decreased from 8.8 to 3.3 and on average 94.5% of the pain area was covered. In our center's subjects (N = 47 patients, 60.3% of all implanted patients in Spain), VAS scores decreased from an average of 8.8-1.7 and pain coverage averaged 96.4%. We used an average of 1.8 electrodes. Worldwide more than 4000 permanent cases have been successfully performed.

CONCLUSIONS

We present implantation techniques whereby a percutaneous lead is placed over the DRG through the use of a special designed delivery sheath. Further investigation of the safety, efficacy, and sustainability of clinical outcomes using these devices is warranted.

Treatment of FBSS Low Back Pain with a Novel Percutaneous DRG Wireless Stimulator: Pilot and Feasibility Study

OBJECTIVES

Test a miniaturized neurostimulator transforaminally placed at the dorsal root ganglion (DRG) and evaluate the device's safety and efficacy in treating failed back surgery syndrome (FBSS) low back pain.

DESIGN

Pilot, two-phase study.

SUBJECTS

Eleven subjects with chronic intractable neuropathic trunk and/or lower limbs pain were included.

METHODS

The system consisted of an implantable, miniaturized stimulator, provided by Stimwave Technologies (Freedom-4) and an external transmitter. Only one stimulator per subject was implanted unilaterally and transforaminally at L1 to L5 levels. During Phase 1 of the study, the stimulators were not anchored. In Phase 2, the stimulators were anchored. Subjects were treated during 45 days after which the stimulator was removed. Pain reduction, implant duration, and stimulator migration were registered.

RESULTS

Overall pain reduction was 59.9%, with only one device placed at one location, covering only a portion of the painful areas in the majority of the subjects. In Phase 1, the non-anchored stimulators migrated a mean of 8.80 mm and in Phase 2 a mean of 1.83 mm. Stimulator migration did not correlate with changes in pain relief. Mean time-to-implant duration was 10 minutes and no adverse events were reported during implant, follow-up period, or after explant.

CONCLUSIONS

The pain reduction results indicate that the Freedom-4 spinal cord stimulation (SCS) Wireless System is a viable treatment of low back pain through stimulation of the DRG, and better overall pain reduction may be achieved by implanting multiple devices. With short percutaneous implant times and excellent safety profile, this new system may offer health cost savings.

Mechanical properties of nerve roots and rami radiculares isolated from fresh pig spinal cords

No reports have described experiments designed to determine the strength characteristics of spinal nerve roots and rami radiculares for the purpose of explaining the complexity of symptoms of medullary cone lesions and cauda equina syndrome. In this study, to explain the pathogenesis of cauda equina syndrome, monoaxial tensile tests were performed to determine the strength characteristics of spinal nerve roots and rami radiculares, and analysis was conducted to evaluate the stress-strain relationship and strength characteristics. Using the same tensile test device, the nerve root and ramus radiculares isolated from the spinal cords of pigs were subjected to the tensile test and stress relaxation test at load strain rates of 0.1, 1, 10, and 100 s^-1 under identical settings. The tensile strength of the nerve root was not rate dependent, while the ramus radiculares tensile strength tended to decrease as the strain rate increased. These findings provide important insights into cauda equina symptoms, radiculopathy, and clinical symptoms of the medullary cone.

Use of neuropathic pain questionnaires in predicting persistent postoperative neuropathic pain following lumbar discectomy for radiculopathy

OBJECT Failed-back surgery syndrome has been historically used to describe extremity neuropathic pain in lumbar disease despite structurally corrective spinal surgery. It is unclear whether specific preoperative pain characteristics can help determine which patients may be susceptible to such postoperative disabling symptoms. METHODS This prospective study analyzed surgical microdiscectomy patients treated for lumbar, degenerative, painful radiculopathy. Clinical parameters included general demographics, preoperative and postoperative clinical examination status, self-reported pain and disability scores, and neuropathic pain scores. The screening tests for neuropathic pain were the Douleur Neuropathique 4 and Leeds Assessment of Neuropathic Symptoms and Signs, with correlation tested for ordinal score and screen positivity. Multiple logistic regression analysis was used to define predictors of postoperative symptomatology. RESULTS Twelve percent of the 250 patients with radiculopathy who underwent microdiscectomy experienced persistent postoperative neuropathic pain (PPNP) with only modest, if any, relief of leg pain. The condition was highly associated with abnormal preoperative screen results for neuropathic pain, but not sex, smoking status, or preoperative pain severity (α = 0.05). Good correlation was seen between the 2 screening tests used in this study for both absolute ordinal score (Spearman ρ = 0.84; p < 0.001) and the threshold for terming the patient as having neuropathic pain features (Spearman ρ = 0.48; p < 0.001). Younger age at treatment also correlated with a higher likelihood of developing PPNP (p = 0.03). CONCLUSIONS This population exhibited a low overall frequency of PPNP. Higher neuropathic pain screening scores correlated strongly with likelihood of significant postoperative leg pain. Further work is required to develop more accurate prognostication tools for radiculopathy patients undergoing structural spinal surgery.

Lumbar dorsal root Ganglia location: an anatomic and MRI assessment

Background

The dorsal root ganglion (DRG) is a key structure in the mechanism of symptomatic radicular pain, weakness and change in sensation. DRG localization can assist in the decision making process of which areas require decompression, and type of procedure that should be performed to treat radicular symptoms. In this study we determine dimensions of lumbar foramina, DRG and its relationship to the neuroforamina through anatomic and magnetic resonance imaging (MRI) evaluation Agreement between MRI and anatomic assessment of DRG location will be determined.

Methods

Sixteen embalmed cadavers, 10 females and 6 males, aged 68 to 106 years had an MRI of the thoracolumbar spine followed by dissection. Measurements made included foraminal height and width, DRG size and nerve root take off angle. The center of the DRG and its relationship to the foramina were measured and the probability of agreement between anatomic and MRI assessment were made.

Results

The greatest width of the DRG was 6.5mm bilaterally at L5 (range 3.2-6.5mm). The nerve root take off angle was largest at L5 on the left (range 50.5o-58.8o) and L4 on the right (range 50.5o-57.2o). The center of the DRG was found bilaterally in the medial zone of the foramen of L1-4 and lateral zone at L5. Foramina size increased from L1 to L5 in the ventral to dorsal and cephalad to caudal direction. Pedicle width increased from L1 to L5. The estimated overall probability of agreement between anatomic and MRI DRG location was 86.3% (95% confidence interval = 77.5% − 92.0%).

Conclusions

The percentage of agreement between MRI and anatomic evaluation of lumbar DRG location significantly exceeded our pre-defined threshold of 70% (p = 0.0013).

Clinical Relevance

Our results aid in surgical decision-making as true anatomic position can be directly correlated to what's seen on MRI.

Nerve stretch injury induced pain pattern and changes in sensory ganglia in a clinically relevant model of limb-lengthening in rabbits

We used a model of tibial lengthening in rabbits to study the postoperative pain pattern during limb-lengthening and morphological changes in the dorsal root ganglia (DRG), including alteration of substance P (SP) expression. Four groups of animals (naive; OG: osteotomized only group; SDG/FDG: slow/fast distraction groups, with 1 mm/3 mm lengthening a day, respectively) were used. Signs of increasing postoperative pain were detected until the 10(th) postoperative day in OG/SDG/FDG, then they decreased in OG but remained higher in SDG/FDG until the distraction finished, suggesting that the pain response is based mainly on surgical trauma until the 10(th) day, while the lengthening extended its duration and increased its intensity. The only morphological change observed in the DRGs was the presence of large vacuoles in some large neurons of OG/SDG/FDG. Cell size analysis of the S1 DRGs showed no cell loss in any of the three groups; a significant increase in the number of SP-positive large DRG cells in the OG; and a significant decrease in the number of SP-immunoreactive small DRG neurons in the SDG/FDG. Faster and larger distraction resulted in more severe signs of pain sensation, and further reduced the number of SP-positive small cells, compared to slow distraction.

Changes in compressed neurons from dogs with acute and severe cauda equina constrictions following intrathecal injection of brain-derived neurotrophic factor-conjugated polymer nanoparticles

This study established a dog model of acute multiple cauda equina constriction by experimental constriction injury (48 hours) of the lumbosacral central processes in dorsal root ganglia neurons. The repair effect of intrathecal injection of brain-derived neurotrophic factor with 15 mg encapsulated biodegradable poly(lactide-co-glycolide) nanoparticles on this injury was then analyzed. Dorsal root ganglion cells (L₇) of all experimental dogs were analyzed using hematoxylin-eosin staining and immunohistochemistry at 1, 2 and 4 weeks following model induction. Intrathecal injection of brain-derived neurotrophic factor can relieve degeneration and inflammation, and elevate the expression of brain-derived neurotrophic factor in sensory neurons of compressed dorsal root ganglion. Simultaneously, intrathecal injection of brain-derived neurotrophic factor obviously improved neurological function in the dog model of acute multiple cauda equina constriction. Results verified that sustained intraspinal delivery of brain-derived neurotrophic factor encapsulated in biodegradable nanoparticles promoted the repair of histomorphology and function of neurons within the dorsal root ganglia in dogs with acute and severe cauda equina syndrome.

A rat model for chronic spinal nerve root compression

OBJECTIVES

The pathophysiology of radiculopathy associated with lumbar spinal stenosis and lumbar disc herniation is incompletely understood. The goal of the present study was to establish a chronic spinal nerve root compression model that can mimic lumbar disc herniation or spinal stenosis using silicone tube compression. We also try to link the pathology changes of damaged nerve root with the reaction of microglia in spinal cord in same rat at different time points.

METHODS

Thirty rats were used in this study. The L5 nerve roots (dorsal and ventral) were exposed by hemilaminectomy; the diameter of the L5 nerve root was measured at the 2 mm proximal from the dorsal root ganglia. The dorsal and ventral nerve roots of L5 were compressed using a silicone tube, and the sham group was only exposed dorsal and ventral roots of L5. Five rats from the sham group were perfused at 8 days after surgery, and 25 rats from the model groups were perfused at 3, 8, 12, 45 days, and 5 months after surgery, each model group was composed of 5 rats according to the time point. The L5 spinal cord segments and nerve root that compressed by silicone tube were harvested from the same rat. Microglia and neuron in the spinal cord were stained by immunohistochemistry, and the nerve root was shown by electron microscope.

RESULTS

In sham-operated rat, the arrangement of axon and myelin sheath is normal, the ventral root is mainly composed of large axon (>6 μm) and it is composed of 46.3 % of all the axons of the ventral root; the average myelin thickness of large axon is 1.86 μm; the dorsal root is mainly composed of medium (2-3.9 or 4-5.9 μm) axons and they are composed of 79.1 % of all the axons of the dorsal root; the average myelin thickness of this category is 0.94 or 1.55 μm. The average myelin thickness of large axon in ventral root reduced to 0.97 and 1.19 μm from more than 1.86 μm after compression for 3 and 8 days separately. Most of myelin sheath disappeared after 12 days of compression; the myelin sheath was partly restored at 45 days after compression which the myelin sheath thickness of large axons in ventral root was 0.47 μm. The medium category in dorsal root reduced to 0.59 or 0.72 μm from 0.94 μm, and 1.55 μm after compression for 3 days (p < 0.05 to p < 0.0001). The medium category axon in dorsal root is also 0.47 μm after compression for 45 days (p ≤ 0.0001). The myelin sheath was almost totally restored at the 5 months of compression; the myelin sheath thickness returned to normal and the axons were intact in structure under EM. The number of Iba1-positive microglia increased by 18.69, 40.44, and 18.49 % after compression for 3, 8, and 12 days separately in the ipsilateral dorsal horn and 21.26, 32.15, 22.87 % in ventral horns, and the activation of microglia was also prominent in contralateral sides of the dorsal and ventral horn at 8 days time point. The microglia cell reconverted to resting status after compression for 45 days or 5 months.

CONCLUSION

The chronic spinal nerve root compression with silicone tube produces a recoverable damage to nerve root, which produces recoverable microglial activation in the spinal cord. These results demonstrated that the chronic spinal nerve root compression with silicone tube could mimic the pathological changes of lumbar spinal stenosis or lumbar disc herniation.

Diffusion tensor imaging and T2 relaxometry of bilateral lumbar nerve roots: feasibility of in-plane imaging

Lower back pain is a common problem frequently encountered without specific biomarkers that correlate well with an individual patient's pain generators. MRI quantification of diffusion and T2 relaxation properties may provide novel insight into the mechanical and inflammatory changes that occur in the lumbosacral nerve roots in patients with lower back pain. Accurate imaging of the spinal nerve roots is difficult because of their small caliber and oblique course in all three planes. Two-dimensional in-plane imaging of the lumbosacral nerve roots requires oblique coronal imaging with large field of view (FOV) in both dimensions, resulting in severe geometric distortions using single-shot echo planar imaging (EPI) techniques. The present work describes initial success using a reduced-FOV single-shot spin-echo EPI acquisition to obtain in-plane diffusion tensor imaging (DTI) and T2 mapping of the bilateral lumbar nerve roots at the L4 level of healthy subjects, minimizing partial volume effects, breathing artifacts and geometric distortions. A significant variation in DTI and T2 mapping metrics is also reported along the course of the normal nerve root. The fractional anisotropy is statistically significantly lower in the dorsal root ganglia (0.287 ± 0.068) than in more distal regions in the spinal nerve (0.402 ± 0.040) (p < 10(-5) ). The T2 relaxation value is statistically significantly higher in the dorsal root ganglia (78.0 ± 11.9 ms) than in more distal regions in the spinal nerve (59.5 ± 7.4 ms) (p < 10(-5) ). The quantification of nerve root DTI and T2 properties using the proposed methodology may identify the specific site of any degenerative and inflammatory changes along the nerve roots of patients with lower back pain.

Activation of glial cells in the spinal cord of a model of lumbar radiculopathy

PURPOSE

Glial cells in the spinal cord of a lumbar radiculopathy model were investigated using immunohistochemical methods. Neuropathic pain is a consequence of neural plasticity. In models of neuropathic pain models, roles for glial cells in the development of pain behaviors have been reported. Accumulating evidence suggests that activation of p38 mitogen-activated protein kinase (p38) in glial cells contributes to the pathogenesis of neuropathic pain. We examined whether activation of glial cells is involved in the development of neuropathic pain-like behavior observed in a model of lumbar radicular pain that we developed. However, the pathogenesis of lumbar radiculopathy and in particular the effect of spinal glial activation on pain transmission in the dorsal horn of the spinal cord are still not fully known.

METHODS

The left L5 spinal root of Sprague-Dawley rats was ligated proximal to the DRG to produce models of lumbar radiculopathy. Protein levels of phosphorylated-p38 (p-p38) in the spinal cord were quantified by Western blot analysis. Double-immunofluorescense studies of p-p38 and specific markers of glia and neurons were performed to determine when and which types of cells were activated in the spinal cord.

RESULTS

We observed p38 activation in hyperactive microglia in the dorsal horn ipsilateral to surgery at 1 and 7 days after root constriction, but not in astrocytes or neurons.

CONCLUSIONS

Constriction of the lumbar root activated microglia in the spinal cord at 1 and 7 days after surgery, and then returned to normal state at 28 days after surgery, while pain behavior continued. These findings suggest that development of lumbar radicular pain may be initiated by activation of microglia.

Avaliação do exercício físico como fator de analgesia em um modelo experimental de ciatalgia

OBJETIVO: Avaliar a eficácia do exercício físico (natação e salto) atuando na redução do quadro álgico de ratos submetidos a um modelo experimental de ciatalgia. MÉTODOS: 24 ratos Wistar foram divididos em quatro grupos: grupo Placebo (GP), grupo Natação (GN), grupo Natação 10% (GN10) e grupo Salto (GS). Todos os grupos foram submetidos ao modelo de ciatalgia e avaliados em relação à dor pós-exercício pelo teste de incapacidade funcional e pelo filamento de Von Frey. RESULTADOS: Na comparação intragrupos houve diferenças significativas, para todos os grupos, nos momentos pós-lesão comparados com o pré-lesão, por ambos os instrumentos de avaliação. Com o filamento de Von Frey observou-se diferença significativa nos grupos GN10 e GS nos momentos finais de avaliação. Na comparação intergrupos não houve diferenças significativas com nenhum instrumento de avaliação. CONCLUSÃO: O tratamento com exercício físico não foi eficaz para reduzir o quadro álgico de ratos submetidos à ciatalgia.

Percutaneous coblation nucleoplasty in patients with contained lumbar disc prolapse: 1 year follow-up in a prospective case series

BACKGROUND

Nucleoplasty appears a successful minimally-invasive treatment for symptomatic contained disc herniation (protrusion). The purpose of this prospective study was to assess the effectiveness of nucleoplasty for alleviating pain and dysfunction in our patients.

METHOD

All patients who presented with established low back and/or leg pain of at least 3 months' duration were clinically followed for 1 year following the nucleoplasty procedure. Self-reported grading of pain using the Visual Analogue Scale (VAS) and the Roland Morris Disability Questionnaire (RMDQ), and subjective global rating of overall satisfaction were recorded and analysed.

RESULTS

Eighty-three patients, aged between 20 and 65 years who were treated with nucleoplasty were included in the study. No complications were noted. At the 12-month-follow-up, the median VAS and RMDQ scores were significantly reduced in the patients who were considered successful (VAS by 6-7 points, RMDQ by 8 points) compared to the patients who were considered failed showing much less reduction. (P = 0.000 in both cases; Mann-Whitney U test.) There was no significant difference in the baseline VAS and RMDQ scores in the two groups. Patients who were considered to have failed the procedure tended to be older. Multi-level disc decompression did not appear to be a risk factor for failure.

CONCLUSIONS

This disc decompression procedure was a safe and effective treatment option for carefully selected patients affected by low back and leg pain due to contained disc herniation.

Changes in blood flow, oxygen tension, action potentials, and vascular permeability induced by arterial ischemia or venous congestion on the lumbar dorsal root ganglia in dogs

It is generally believed that radiculopathy associated with the degenerative conditions of the spine may result from both mechanical compression and circulatory disturbance. However, the basic pathophysiology of circulatory disturbance induced by ischemia and congestion is not fully understood. This study investigated the effect of ischemia and congestion on the dorsal root ganglion (DRG) using an in vivo model. The sixth and seventh lumbar laminae were removed and the seventh lumbar DRG was exposed using adult dogs. The aorta was clamped as an ischemic model in the DRG, and the inferior vena cava was clamped as a congestion model at the sixth costal level for 30 min using forceps transpleurally. Measurements of blood flow, partial oxygen pressure, and action potentials in the DRG were recorded over a period of 1 h after clamp release. Finally, we examined the status of intraganglionic blood permeability under a fluorescence microscope following injection of Evans blue albumin into the cephalic vein to determine the type of circulatory disturbance occurring in the DRG. Immediately after inferior vena cava clamping, the central venous pressure increased approximately four times and marked extravasation of protein tracers was induced in the lumbar DRG. Blood flow, partial oxygen pressures, and action potentials within the DRG were more severely affected by the aorta clamping; however, this ischemic model did not reveal any permeability changes in the DRG. The permeability change in the DRG was more easily increased via venous congestion than by arterial ischemia. The intraganglionic venous flow was stopped with compression at much lower pressures than that needed to impact arterial flow. From a clinical perspective, intraganglionic edema formation, rather than arterial ischemia, may be an earlier phenomenon inducing DRG dysfunction.

Microsurgical approach to the spinal canal in rats

The spinal cord of the rat has become a widely used model for biodynamic, pharmaceutical and neurological experiments. However, no standard procedure to approach the spinal cord in rats has been published in detail. We present a description of a dorsal approach to the spine, spinal canal and myelon of the rat. This approach provides sufficient exposure of the neural structures to perform extended microsurgery at the spinal nerve-roots, the lateral and dorsal myelon and vertebral structures under a surgical microscope. Perioperative management, anaesthesia and anatomical landmarks are discussed and common pitfalls are described.

Microvascular system of the lumbar dorsal root ganglia in rats. Part I: a 3D analysis with scanning electron microscopy of vascular corrosion casts

Object

So far, the morphological features of the vascular system supplying the dorsal root ganglion (DRG) have been inferred only from microangiograms. However, in the past most of these studies lacked 3D observations. This study presents the details of the microvasculature of the lumbar DRG visualized by scanning electron microscopy of vascular corrosion casts.

Methods

Wistar rats were anesthetized with intraperitoneal sodium pentobarbital. After thoracotomy, the vascular system was perfused with heparinized saline, and Mercox resin was injected into the thoracic aorta. After polymerization of the resin, the vascular casts were macerated with potassium hydroxide, washed with water, and dried. The casts were examined with a scanning electron microscope.

Results

The vascular cast of the DRG was observed to have a higher density of vessels than the nerve root. Bifurcation or anastomoses of capillaries took place at approximately right angles, in a T-shaped pattern. Within the DRG, both the arterial supply and the capillary network contained blood flow control structures (ring-shaped constrictions in the cast probably representing a vascular sphincter in the microvessel). Three types of vessels could be distinguished: tortuous, straight, and bead-like capillaries. The dilations, bulges, and tortuousness of capillaries could serve the function of locally increasing the capillary surface area in a sensory neuron.

Conclusions

The results of this study suggest a causal relationship between the metabolic demands of local neuronal activity and both the density of the capillary network and the placement of the blood flow control structures.

Efeitos do ultrassom terapêutico em modelo experimental de ciatalgia

A ciática possui grande prevalência geral e seu tratamento tende a resolver as causas de compressão nervosa. A fisioterapia objetiva reduzir os sintomas causados pela compressão. O presente estudo teve como objetivo avaliar a eficácia do ultrassom terapêutico sobre a dor, em animais submetidos a modelo experimental de ciatalgia. Foram usados 18 ratos neste estudo, divididos em três grupos: GS (n = 4), submetido a modelo de ciatalgia e tratados com ultrassom desligado; GUP (n = 7), submetido à ciatalgia e tratados com ultrassom pulsado 2W/cm² (SATP; 0,4 - SATA); e grupo GUC (n = 7), submetido à ciática e ultrassom contínuo (0,4W/cm²). O nervo ciático do membro posterior direito foi exposto à compressão com fio categute em quatro pontos. No 3º dia pós-operatório (PO), iniciou-se tratamento indireto por quatro dias. No 9º dia PO, o tratamento direto começou sobre a área do procedimento cirúrgico, por cinco dias consecutivos. O tempo de elevação da pata, durante a marcha, foi avaliado antes e após a ciatalgia, no 3º, 6º, 9º e 13º PO. Os resultados demonstraram que a aplicação do ultrassom reduziu a dor com ambos os tratamentos efetivos e tendeu a ser mais eficaz na forma pulsada.

Ultra-som terapêutico contínuo térmico em modelo experimental de ciatalgia

O ultra-som é um recurso fisioterapêutico que pode atuar na redução dos sintomas da ciatalgia. O objetivo deste estudo foi verificar a eficácia do ultra-som terapêutico, no modo contínuo, em duas diferentes densidades de potência (0,5 W/cm² e 1 W/cm²), na redução do quadro álgico em ratos submetidos a modelo experimental de ciatalgia. Foram utilizados 20 ratos, divididos em 3 grupos: G1 (n=6) submetido à ciatalgia e a tratamento placebo; G2 (n=7) submetido à ciatalgia e tratado com ultra-som com 0,5 W/cm²; e G3 (n=7) submetido à ciatalgia e tratado com ultra-som com 1 W/cm². A ciatalgia foi provocada por lesão cirúrgica de compressão do nervo no membro posterior direito de todos os animais. O tratamento na região do procedimento cirúrgico, iniciado no 3º dia pós-operatório, consistiu em 10 sessões diárias de 5 minutos. Verificou-se a dor pelo do tempo de elevação da pata (TEP) durante a marcha, medido pré-cirurgia e em mais cinco momentos. Os resultados mostram aumentos no TEP em todos os grupos após a lesão; e, naqueles tratados com ultra-som terapêutico, houve diminuição significativa da TEP, restaurando-se os valores iniciais, sendo mais precoce e intensa em G2. Conclui-se que a entrega na forma continua do ultra-som terapêutico foi eficaz na redução da dor ciática.

Immunohistochemical and histological study of human uncovertebral joints: a preliminary investigation

STUDY DESIGN

A descriptive cadaveric study.

OBJECTIVE

To investigate the anatomy and innervation of the uncovertebral joint to determine if it is synovial in nature and capable of generating pain.

SUMMARY OF BACKGROUND DATA

There is controversy with regard to the anatomic and histological makeup of the uncovertebral interface with some authors considering it a joint and others disc tissue. No research has investigated the presence of pain generating neurotransmitters within the uncovertebral cartilaginous and capsular tissue.

METHODS

Tissue from uncovertebral capsule and cartilage was harvested for each uncovertebral surface starting at the C2-C3 to the C6-C7 cervical segment. The tissue was placed in 4% paraformaldehyde fixative, then dehydrated and embedded in paraffin. Ten micron sections were cut through the tissue blocks and mounted on slides. The tissue was rehydrated and either stained with hematoxylin and eosin (H and E) or immunostained with antisera against protein gene product 9.5 (PGP 9.5), substance P (SP), neuropeptide Y (NPY), and calcitonin gene-related peptide (CGRP).

RESULTS

The sample consisted of 2 unembalmed fresh male human cadavers of a mean age of 83 years. Chondrocytes and synoviocytes were identified at the capsular tissue of each uncovertebral interface from C2-C3-C6-C7. Immunoreactivity for PGP 9.5, SP, CGRP, and NPY was observed at all uncovertebral interface levels in capsular tissue.

CONCLUSION

The presence of both synoviocytes and chondrocytes has been recorded in the present study, suggesting that the uncovertebral interface is synovial in nature. Immunoreactivity to PGP 9.5, SP, CGRP, and NPY indicates the presence of nerve fibers from both the somatic and autonomic nervous systems. These findings suggest that the uncovertebral joints are potential pain generators in the cervical spine.

Cytokine mRNA expression in painful radiculopathy

Inflammatory cytokines contribute to lumbar radiculopathy. Regulation of cytokines for transient cervical injuries, with or without longer-lasting inflammation, remains to be defined. The C7 root in the rat underwent compression (10gf), chromic gut suture exposure (chr), or their combination (10gf+chr). Ipsilateral C7 spinal cord and dorsal root ganglia (DRG) were harvested at 1 hour after injury for real-time PCR analysis of IL-1beta, IL-6, and TNF-alpha. Cytokine mRNA increased after all 3 injuries. TNF-alpha mRNA in the DRG was significantly increased over sham after 10gf+chr (P = .026). Spinal IL-1beta was significantly increased over sham after 10gf and 10gf+chr (P < .024); IL-6 was significantly increased after 10gf+chr (P < .024). In separate studies, the soluble TNF-alpha receptor was administered at injury and again at 6 hours in all injury paradigms. Allodynia was assessed and tissue samples were harvested for cytokine PCR. Allodynia significantly decreased with receptor administration for 10gf and 10gf+chr (P < .005). Treatment also significantly decreased IL-1beta and TNF-alpha mRNA in the DRG for 10gf+chr (P < .028) at day 1. Results indicate an acute, robust cytokine response in cervical nerve root injury with varying patterns, dependent on injury type, and that early increases in TNF-alpha mRNA in the DRG may drive pain-related signaling for transient cervical injuries.

PERSPECTIVE

Inflammatory cytokine mRNA in the DRG and spinal cord are defined after painful cervical nerve root injury. Studies describe a role for TNF-alpha in mediating behavioral sensitivity and inflammatory cytokines in transient painful radiculopathy. Results outline an early response of inflammatory cytokine upregulation in cervical pain.

Proteomic analysis of differential proteins related to the neuropathic pain and neuroprotection in the dorsal root ganglion following its chronic compression in rats

The aim of the study was to identify the differential protein expressions related to neuropathic pain and neuroprotection in the dorsal root ganglion (DRG) following chronic compression of DRG (CCD) in rats. We conducted a proteomics study of L(4) and L(5) DRG after CCD for 28 days. A total of 98 protein spots were detected with significant changes in their expression levels after CCD and 15 protein spots were identified by the matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. Of these proteins, annexin A2, protein kinase C epsilon (PKCepsilon), glyceraldehyde-3-phosphate dehydrogenases (GAPDH), and heat shock protein 70 (HSP70) were up-regulated significantly compared with the normal control. These four proteins and p11, which was annexin A2 light chain, were further examined by Western blotting. The results of Western blotting and the proteomic analysis showed consistent data. Moreover, real-time quantitative RT-PCR experiments indicated that CCD-induced increase in protein levels was associated with an up-regulation of annexin A2 and PKCepsilon gene expression. In conclusion, this study highlights the molecular process in DRG underlying neuropathic pain. CCD is associated with the up-regulation of annexin A2 and PKCepsilon and their related genes. The up-regulation of GAPDH and HSP70 suggests that there exist concurrent processes of nervous injury and neuroprotection in the course of neuropathic pain.