Applicative value of T2 mapping in evaluating lumbosacral nerve root injury induced by lumbosacral disc herniation.

BACKGROUND: To alleviate the damage caused by nerve root entrapment mediated by lumbosacral disc herniation (LDH), an imaging method that allows quantitative evaluation of the lumbosacral nerve injury is necessary. PURPOSE: To investigate the diagnostic value of magnetic resonance (MR) T2 mapping in nerve root injury caused by LDH. MATERIAL AND METHODS: A total of 70 patients with unilateral sciatic nerve pain and 35 healthy volunteers were divided into three groups: LDH with nerve root entrapment; LDH without nerve root entrapment; and 35 healthy volunteers. All participants underwent 3.0-T MR with T1-weighted (T1W) imaging, T2-weighted (T2W) imaging, and T2-mapping images. T2 was measured and observed with the left and right nerve roots of the L4-S1 segments in healthy volunteers; the differences between the three groups were compared. T2 and the relaxation rate of nerve root injury were analyzed. RESULTS: T2 showed significant differences among the three groups (F = 89.494; P = 0.000), receiver operating characteristic curve revealed that the T2 relaxation threshold was 79 ms, the area under curve (AUC) area was 0.86, sensitivity was 0.77, and specificity was 0.74; the T2 relaxation rate was 1.06, the AUC area was 0.88, sensitivity was 0.74, and specificity was 0.85. CONCLUSION: T2 mapping could quantitatively evaluate the nerve root injury with lumbar disc degeneration. Hence, it can be used for the clinical evaluation of nerve root entrapment caused by LDH.

Lumbar plexus safe working zones with lateral lumbar interbody fusion: a systematic review and meta-analysis.

PURPOSE: Significant risk of injury to the lumbar plexus and its departing motor and sensory nerves exists with lateral lumbar interbody fusion (LLIF). Several cadaveric and imaging studies have investigated the lumbar plexus position with respect to the vertebral body anteroposterior plane. To date, no systematic review and meta-analysis of the lumbar plexus safe working zones for LLIF has been performed. METHODS: This systematic review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Relevant studies reporting on the position of the lumbar plexus with relation to the vertebral body in the anteroposterior plane were identified from a PubMed database query. Quantitative analysis was performed using Welch's t test. RESULTS: Eighteen studies were included, encompassing 1005 subjects and 2472 intervertebral levels. Eleven studies used supine magnetic resonance imaging (MRI) with in vivo subjects. Seven studies used cadavers, five of which performed dissection in the left lateral decubitus position. A significant correlation (p < 0.001) existed between anterior lumbar plexus displacement and evaluation with in vivo MRI at all levels between L1-L5 compared with cadaveric measurement. Supine position was also associated with significant (p < 0.001) anterior shift of the lumbar plexus at all levels between L1-L5. CONCLUSIONS: This is the first comprehensive systematic review and meta-analysis of the lumbar neural components and safe working zones for LLIF. Our analysis suggests that the lumbar plexus is significantly displaced ventrally with the supine compared to lateral decubitus position, and that MRI may overestimate ventral encroachment of lumbar plexus.

Localization of Nerve Growth Factor Expression to Structurally Damaged Cartilaginous Tissues in Human Lumbar Facet Joint Osteoarthritis.

Purpose: Nerve Growth Factor (NGF) is a pivotal mediator of chronic pain and plays a role in bone remodelling. Through its high affinity receptor TrkA, NGF induces substance P (SP) as key downstream mediator of pain and local inflammation. Here we analysed NGF, TrkA and SP tissue distribution in facet joint osteoarthritis (FJOA), a major cause of chronic low back pain. Methods: FJOA specimens (n=19) were harvested from patients undergoing intervertebral fusion surgery. Radiologic grading of FJOA and spinal stenosis, followed by immunohistochemistry for NGF, TrkA and SP on consecutive tissue sections, was performed in ten specimens. Explant cultures (n=9) were used to assess secretion of NGF, IL-6, and SP by FJOA osteochondral tissues under basal and inflammatory conditions. Results: NGF was predominantly expressed in damaged cartilaginous tissues (80%), occasionally in bone marrow (20%), but not in osteochondral vascular channels. NGF area fraction in cartilage was not associated with the extent of proteoglycan loss or radiologic FJOA severity. Consecutive sections showed that NGF and SP expression was localized at structurally damaged cartilage, in absence of TrkA expression. SP and TrkA were expressed in subchondral bone marrow in both presence and absence of NGF. Low level NGF, but not SP secretion, was detected in four out of eighteen FJOA explants under both basal or inflammatory conditions (n=2 each). Conclusion: NGF is associated with SP expression and structural cartilage damage in osteoarthritic facet joints, but not with radiologic disease severity. NGF tissue distribution in FJOA differs from predominant subchondral bone expression reported for knee OA.

Anatomical study and clinical significance of rami communicantes of the lumbar spine.

BACKGROUND AND OBJECTIVES: Rami communicantes (RC) infiltration and radiofrequency lesions are new techniques for the treatment of discogenic low back pain (DLBP). Their efficacy is controversial, and the classification of RC remains unclear. We aimed to explore the differences between RC and reclassify RC according to their anatomical characteristics. METHODS: Sixteen sides of the lumbar spine from eight adult male embalmed cadavers were dissected. The presence of RC was noted. The morphology, origin, distribution, course, quantity and spatial orientation of RC on the lumbar spine were examined. The length and width of the RC were measured by a caliper. RESULTS: A total of 213 RC were found in the 8 cadavers in the lumbar region. RC were divided into three types: superficial rami (70, 32.86%), which penetrated the psoas major (PM) and ran above the aponeurosis of the PM; deep rami (125, 58.69%), which ran along the waist of the vertebral body beneath the aponeurosis of the PM; and discal rami, which ran over and adhered to the surface of the intervertebral disc. Superficial rami were divided into two subtypes: oblique rami (45, 21.13%) and parabolic rami (25, 11.74%), which crossed the vertebra and the disc in an oblique and a parabolic course, respectively. CONCLUSIONS: RC should play an important role in the innervation of the lumbar spine. Detailed knowledge of RC in the lumbar region may help surgeons improve the efficacy of infiltration and percutaneous radiofrequency as a supplementary treatment for DLBP.

Origin, branching pattern, foraminal and intraspinal distribution of the human lumbar sinuvertebral nerves.

BACKGROUND CONTEXT: The lumbar sinuvertebral nerve (SVN) innervates the outer posterior intervertebral disc (IVD); it is thought to mediate discogenic low-back pain (LBP). Controversy, however, exists on its origins at higher (L1-L2) versus lower (L3-L5) lumbar levels. Additionally, lack of knowledge regarding its foraminal and intraspinal branching patterns and extensions may lead to iatrogenic damage. PURPOSE: To systematically describe the origins of the L2 and L5 SVNs, their morphological variation in the intervertebral foramen (IVF) and intraspinal distribution. STUDY DESIGN: Dissection-based study of 20 SVNs with histological confirmation in five embalmed human cadavers. METHODS: The origin, branching pattern and distribution of the L2 and L5 SVNs was investigated bilaterally in five human cadavers using dorsal and anterolateral dissection approaches. Parameters studied included somatic and/or autonomic SVN root contributions, foraminal SVN morphology and course, diameter, branching point, intraspinal distribution and IVD innervation pattern. Nerve tissue was confirmed by immunostaining for neurofilament and S100 proteins. RESULTS: The SVN and its origins was identified in all except one IVF at L2 and in all foramina at L5. At L2, the SVN arose in nearly 90% of sides from both somatic and autonomic roots and at L5 in 40% of sides. The remaining SVNs were formed by purely autonomic roots. The SVN arose from significantly more roots at L2 than L5 (3.1 ± 0.3 vs. 1.9 ± 0.3, respectively; p=.022). Four different SVN morphologies could be discerned in the L2 IVF: single filament (22%), multiple (parallel or diverging) filament (33%), immediate splitting (22%) and plexiform (22%) types, whereas the L5 SVN consisted of single (90%) and multiple (10%) filament types. SVN filaments were significantly thicker at L2 than L5 (0.48 ± 0.06 mm vs. 0.33 ± 0.02 mm, respectively; p=.043). Ascending SVN filaments coursed roughly parallel to the exiting spinal nerve root trajectory at L2 and L5. Branching of the SVN into ascending and descending branches occurred mostly intraspinal both at L2 and L5. Spinal canal distribution was also similar for L2 and L5 SVNs. Lumbar posterior IVDs were innervated by the descending branch of the parent SVN and ascending branch of the subjacent SVN. CONCLUSIONS: The SVN at L2 originates from both somatic and autonomic roots in 90% of cases and at L5 in 40% of cases. The remaining SVNs are purely autonomic. In the IVF, the L2 SVN is morphologically heterogeneous, but generally consists of numerous filaments, whereas at L5 90% contains a single SVN filament. The L2 SVN is formed by more roots and is thicker than the L5 SVN. Intraspinal SVN distribution is confined to its level of origin; lumbar posterior IVDs are innervated by corresponding and subjacent SVNs (ie, two spinal levels). CLINICAL SIGNIFICANCE: Our findings indicate that L5 discogenic LBP may be mediated both segmentally and nonsegmentally in 40% of cases and nonsegmentally in 60% of cases. Failure of lower lumbar discogenic pain treatment may be the result of only interrupting the nonsegmental pathway, but not the segmental one as well. Relating SVN anatomy to microsurgical spinal approaches may prevent iatrogenic damage to the SVN and the formation of postsurgical back pain.

Botulinum Toxin Type A for Lumbar Sympathetic Ganglion Block in Complex Regional Pain Syndrome: A Randomized Trial.

BACKGROUND: The present study was designed to test the hypothesis that botulinum toxin would prolong the duration of a lumbar sympathetic block measured through a sustained increase in skin temperature. The authors performed a randomized, double-blind, controlled trial to investigate the clinical outcome of botulinum toxin type A for lumbar sympathetic ganglion block in patients with complex regional pain syndrome. METHODS: Lumbar sympathetic ganglion block was conducted in patients with lower-extremity complex regional pain syndrome using 75 IU of botulinum toxin type A (botulinum toxin group) and local anesthetic (control group). The primary outcome was the change in the relative temperature difference on the blocked sole compared with the contralateral sole at 1 postoperative month. The secondary outcomes were the 3-month changes in relative temperature differences, as well as the pain intensity changes. RESULTS: A total of 48 participants (N = 24/group) were randomly assigned. The change in relative temperature increase was higher in the botulinum toxin group than in the control group (1.0°C ± 1.3 vs. 0.1°C ± 0.8, respectively; difference: 0.9°C [95% CI, 0.3 to 1.5]; P = 0.006), which was maintained at 3 months (1.1°C ± 0.8 vs. -0.2°C ± 1.2, respectively; P = 0.009). Moreover, pain intensity was greatly reduced in the botulinum toxin group compared with the control group at 1 month (-2.2 ± 1.0 vs. -1.0 ± 1.6, respectively; P = 0.003) and 3 months (-2.0 ± 1.0 vs. -0.6 ± 1.6, respectively; P = 0.003). There were no severe adverse events pertinent to botulinum toxin injection. CONCLUSIONS: In patients with complex regional pain syndrome, lumbar sympathetic ganglion block using botulinum toxin type A increased the temperature of the affected foot for 3 months and also reduced the pain.

Magnetic resonance imaging-guided lumbar nerve root infiltrations: optimization of an in-house protocol.

BACKGROUND: For the treatment of radicular pain, nerve root infiltrations can be performed under MRI guidance in select, typically younger, patients where repeated CT exams are not desirable due to associated radiation risk, or potential allergic reactions to iodinated contrast medium. METHODS: Fifteen 3 T MRI-guided nerve root infiltrations were performed in 12 patients with a dedicated surface coil combined with the standard spine coil, using a breathhold PD sequence. The needle artifact on the MR images and the distance between the needle tip and the infiltrated nerve root were measured. RESULTS: The distance between the needle tip and the nerve root was 2.1 ± 1.4 mm. The visual artifact width, perpendicular to the needle long axis, was 2.1 ± 0.7 mm. No adverse events were reported. CONCLUSION: This technical note describes the optimization of the procedure in a 3 T magnetic field, including reported procedure time and an assessment of targeting precision.

A comparison of three different surgery approaches and methods for neurologically intact thoracolumbar fractures: a retrospective study.

OBJECTIVES: The purpose of this study was to evaluate and compare the feasibility, safety, and efficacy of conventional open pedicle screw fixation (COPSF), percutaneous pedicle screw fixation (PPSF), and paraspinal posterior open approach pedicle screw fixation (POPSF) for treating neurologically intact thoracolumbar fractures. METHODS: We retrospectively reviewed 108 patients who were posteriorly stabilized without graft fusion. Among them, 36 patients underwent COPSF, 38 patients underwent PPSF, and 34 patients underwent POPSF. The clinical outcomes, relative operation indexes, and radiological findings were assessed and compared among the 3 groups. RESULTS: All of the patients were followed up for a mean time of 20 months. The PPSF group and POPSF group had shorter operation times, lower amounts of intraoperative blood loss, and shorter postoperative hospital stays than the COPSF group (P < 0.05). The radiation times and hospitalization costs were highest in the PPSF group (P < 0.05). Every group exhibited significant improvements in the Cobb angle (CA) and the vertebral body angle (VBA) correction (all P < 0.05). The COPSF group and the POPSF group had better improvements than the PPSF group at 3 days postoperation and the POPSF group had the best improvements in the last follow-up (P < 0.05). CONCLUSION: Both PPSF and POPSF achieved similar effects as COPSF while also resulting in lower incidences of injury. PPSF is more advantageous in the early rehabilitation time period, compared with COPSF, but POPSF is a better option when considering the long-term effects, the costs of treatment, and the radiation times.

Motor Unit Number Index in Evaluating Patients With Lumbar Spinal Stenosis.

OBJECTIVE: Motor unit number index is a quantitative electrophysiological measure that provides an index of the number of motor neurons supplying a muscle. The aim of this exploratory study was to assess the utility of motor unit number index in the evaluation of patients with lumbar spinal stenosis. DESIGN: Participants were assigned to three groups: clinical and radiological lumbar stenosis (lumbar spinal stenosis with neurogenic intermittent claudication), group A; radiological lumbar spinal stenosis without neurogenic intermittent claudication, group B; and a control group, group C. Patients self-rated their pain and functional disability using the numerical rating scale and a series of functional questionnaires. An electromyographer performed nerve conduction tests, electromyography, and motor unit number index testing. RESULTS: Seventeen patients completed the study. There were 9, 5, and 3 patients in groups A, B, and C, respectively. There were no discernable differences in motor unit number index values of any individual muscle or combined motor unit number index score between the three groups. Motor unit number index values did not correlate to pain/functional measures. CONCLUSIONS: In this exploratory study, motor unit number index did not demonstrate discriminatory ability between patients with lumbar spinal stenosis and was not correlated with pain and functional measures. Further study is needed to explore motor unit number index's role in longitudinal evaluation of patients with the clinical syndrome of lumbar spinal stenosis.

Does the L5 spinal nerve move? Anatomical evaluation with implications for postoperative L5 nerve palsy.

PURPOSE: While palsy of the L5 nerve root due to stretch injury is a known complication in complex lumbosacral spine surgery, the underlying pathophysiology remains unclear. The goal of this cadaveric study was to quantify movement of the L5 nerve root during flexion/extension of the hip and lower lumbar spine. METHODS: Five fresh-frozen human cadavers were dissected on both sides to expose the lumbar vertebral bodies and the L5 nerve roots. Movement of the L5 nerve root was tested during flexion and extension of the hip and lower lumbar spine. Four steps were undertaken to characterize these movements: (1) removal of the bilateral psoas muscles, (2) removal of the lumbar vertebral bodies including the transforaminal ligaments from L3 to L5, (3) opening and removing the dura mater laterally to visualize the rootlets, and (4) removal of remaining soft tissue surrounding the L5 nerve root. Two metal bars were inserted into the sacral body at the level of S1 as fixed landmarks. The tips of these bars were connected to make a line for the ruler that was used to measure movement of the L5 nerve roots. Movement was regarded as measurable when there was an L5 nerve excursion of at least 1 mm. RESULTS: The mean age at death was 86.6 years (range 68-89 years). None of the four steps revealed any measurable movement after flexion/extension of the hip and lower lumbar spine on either side (< 1 mm). Flexion of the hip and lower lumbar spine revealed lax L5 nerve roots. Extension of the hip and lower lumbar spine showed taut ones. CONCLUSION: Significant movement or displacement of the L5 nerve root could not be quantified in this study. No mechanical cause for L5 nerve palsy could be identified so the etiology of the condition remains unclear.

Gross anatomical study of the thoracolumbar primary dorsal branches and their course from the spinal cord to the skin in the cat.

The course of spinal nerves and the corresponding cutaneous areas are fundamental for numerous therapeutic approaches used in complementary veterinary medicine. Positive effects of these methods are primarily based on segmental reflex arcs which are associated with the course of the spinal nerves. In this morphological study, the lateral cutaneous branches of the thoracolumbar dorsal branches from Th9 to L7 were examined in cats with special regard to their anatomical course. A four-layer dissection was carried out to reveal the course of nerves between the intervertebral foramina and their point of entry into the skin, starting in the dorsal midline. Dorsal branch courses and covered distances were documented and measured in each layer. The covered distance was evaluated by the Caudal Shift Index (CSIn ) on both body sides and within each layer. The 'back region' was used as relative dimensional unit, describing the distance between the cranial tips of two consecutive spinous processes. Overall, the mean CSIn for dorsal branches of Th9 to L7 amounted to three back regions from the intervertebral foramen to the skin entry point of a dorsal nerve branch. This provides therapists with clues and should be put into practice, by extending the treatment area up to three segments caudally from the nerve exit point. Furthermore, the results of this study present new data on inferred lumbar dermatomes in cats, data which until now have only been transferred from other species. These results may serve as an anatomical foundation for manual therapies.

Cost-Effectiveness of Radiofrequency Denervation for Patients With Chronic Low Back Pain: The MINT Randomized Clinical Trials.

OBJECTIVES: To evaluate the cost-effectiveness of radiofrequency denervation when added to a standardized exercise program for patients with chronic low back pain. METHODS: An economic evaluation was conducted alongside 3 pragmatic multicenter, nonblinded randomized clinical trials (RCTs) in The Netherlands with a follow up of 52 weeks. Eligible participants were included between January 1, 2013, and October 24, 2014, and had chronic low back pain; a positive diagnostic block at the facet joints (n = 251), sacroiliac (SI) joints (n = 228), or a combination of facet joints, SI joints, and intervertebral discs (n = 202); and were unresponsive to initial conservative care. Quality-adjusted life-years (QALYs) and societal costs were measured using self-reported questionnaires. Missing data were imputed using multiple imputation. Bootstrapping was used to estimate statistical uncertainty. RESULTS: After 52 weeks, no difference in costs between groups was found in the facet joint or combination RCT. The total costs were significantly higher for the intervention group in the SI joint RCT. The maximum probability of radiofrequency denervation being cost-effective when added to a standardized exercise program ranged from 0.10 in the facet joint RCT to 0.17 in the SI joint RCT irrespective of the ceiling ratio, and 0.65 at a ceiling ratio of €30 000 per QALY in the combination RCT. CONCLUSIONS: Although equivocal among patients with symptoms in a combination of the facet joints, SI joints, and intervertebral discs, evidence suggests that radiofrequency denervation combined with a standardized exercise program cannot be considered cost-effective from a societal perspective for patients with chronic low back pain originating from either facet or SI joints in a Dutch healthcare setting.

Diagnosis of lumbar radiculopathy using simultaneous MR neurography and apparent T2 mapping.

We sought to assess the utility of simultaneous apparent T2 mapping and neurography with the nerve-sheath signal increased by inked rest-tissue rapid acquisition of relaxation-enhancement imaging (SHINKEI-Quant) for the quantitative evaluation of compressed nerves in patients with lumbar radiculopathy. Thirty-two patients with lumbar radiculopathy and 5 healthy subjects underwent simultaneous apparent T2 mapping and neurography with SHINKEI-Quant. Regions of interest (ROIs) were placed in the lumbar dorsal root ganglia (DRG) and the spinal nerves distal to the lumbar nerves bilaterally at L4-S1. The T2 relaxation times were measured on the affected and unaffected sides. The T2 ratio was calculated as the affected side/unaffected side. Pearson correlation coefficients were calculated to determine the correlation between the T2 relaxation times or T2 ratio and clinical symptoms. An ROC curve was used to examine the diagnostic accuracy and threshold of the T2 relaxation times and T2 ratio. We observed no significant differences in the T2 relaxation times between the nerve roots on the left and right at each spinal level in healthy subjects. In patients, lumbar neurography revealed swelling of the involved nerve, and prolonged T2 relaxation times compared with that of the contralateral nerve. The T2 ratio correlated with leg pain. The ROC analysis revealed that the T2 relaxation time threshold was 127 ms and the T2 ratio threshold was 1.07. To our knowledge, this is the first study to show the utility of SHINKEI-Quant for the quantitative evaluation of lumbar radiculopathy.

Muscle responses to radicular stimulation during lumbo-sacral dorsal rhizotomy for spastic diplegia: Insights to myotome innervation.

OBJECTIVE: Most of knowledge on muscle radicular innervation was from explorations in root/spinal cord pathologies. Direct and individual access to each of the lumbar-sacral -ventral and dorsal- nerve roots during dorsal rhizotomy for spastic diplegia allows precise study of the corresponding muscle innervation. Authors report the lumbo-sacral segmental myotomal organization obtained from recordings of muscle responses to root stimulation in a 20-children prospective series. METHODS: Seven key-muscles in each lower limb and anal sphincter were Electromyography (EMG)-recorded and clinically observed by physiotherapist during L2-to-S2 dorsal rhizotomy. Ventral roots (VR), for topographical mapping, and dorsal roots (DR), for segmental excitability testing, were stimulated, just above threshold for eliciting muscular response. RESULTS: In 70% of the muscles studied, VR innervation was pluri-radicular, from 2-to-4 roots, with 1 or 2 roots being dominant at each level. Overlapping was important. Muscle responses to DR stimulation were 1.75 times more extended compared to VR stimulation. Inter-individual variability was important. CONCLUSIONS: Accuracy of root identification and stimulation with the used method brings some more precise information to radicular functional anatomy. SIGNIFICANCE: Those neurophysiological findings plead for performing Intra-Operative Neuromonitoring when dealing with surgery in the lumbar-sacral roots.

The phenotypic morphology of human lumbar plexus roots associated with changes in the thoracolumbar vertebral count and trade-off.

This study investigated the developmental basis for the human phenotypic morphology of the interaction between the vertebrae and the nerve plexus by evaluating changes in the human lumbar plexus according to various thoracolumbar formulas. The dissection found that the changes in lumbar nerve roots reported by experimental embryology studies to be concomitant with thoracolumbar trade-off, i.e., a change in vertebrae from thoracic to lumbar with no change in the overall thoracolumbar count, were not apparent in humans with the usual 17 or mutant 16 thoracolumbar vertebrae. When vertebral changes in two segments were examined by comparing spines with a reduced thoracolumbar count of 16 to those with an increased count of 18, this tended to show only a single-segment caudal shift of the lumbar plexus. We cannot provide evidence for the phylogenetic difference in the concomitant changes of lumbar nerves and vertebrae, but comparisons between experimental rodents and humans highlighted fewer and shorter lumbar vertebra and more complicated lumbar plexus in humans. Therefore, these multiple differences may contribute to a human phenotypic morphology that is not evident in the concomitant transformation of vertebrae and lumbar nerves reported in experimental rodents.

Direct anterior decompression of L4 and L5 nerve root in sacral fractures using the pararectus approach: a technical note.

PURPOSE: To describe a new surgical technique for neurolysis and decompression of L4 and L5 nerve root entrapment after vertical sacral fractures via the pararectus approach for acetabular fractures, and to present four case examples. PATIENTS AND METHODS: We retrospectively evaluated four patients suffering radiculopathy from entrapment of the L4 or L5 nerve root in vertical sacral fractures between January and December 2016. The mean follow-up period after surgery was 18 (range 7-27) months. All patients underwent direct decompression and neurolysis of the L4 and L5 nerve roots via the single-incision, intrapelvic, extraperitoneal pararectus approach. RESULTS: In all patients, the L4 and L5 nerve root was successfully visualized and decompressed, proving feasibility of the pararectus approach for this indication. No patient presented with a neural tear. Complete neurologic recovery was present in one patient at last follow-up; two patients had incomplete recovery of their radiculopathy; and one patient had no improvement after nerve root decompression. CONCLUSIONS: The pararectus approach allows for sufficient visualisation and direct decompression and neurolysis of the L4 and L5 nerve root entrapped in vertical sacral fractures. Although neurologic recovery was not achieved in all patients in this small case series, the approach may be a suitable alternative to posterior approaches and other anterior approaches such as the lateral window of the ilioinguinal approach.

Using EMG to deliver lumbar dynamic electrical stimulation to facilitate cortico-spinal excitability.

BACKGROUND: Potentiation of synaptic activity in spinal networks is reflected in the magnitude of modulation of motor responses evoked by spinal and cortical input. After spinal cord injury, motor evoked responses can be facilitated by pairing cortical and peripheral nerve stimuli. OBJECTIVE: To facilitate synaptic potentiation of cortico-spinal input with epidural electrical stimulation, we designed a novel neuromodulation method called dynamic stimulation (DS), using patterns derived from hind limb EMG signal during stepping. METHODS: DS was applied dorsally to the lumbar enlargement through a high-density epidural array composed of independent platinum-based micro-electrodes. RESULTS: In fully anesthetized intact adult rats, at the interface array/spinal cord, the temporal and spatial features of DS neuromodulation affected the entire lumbosacral network, particularly the most rostral and caudal segments covered by the array. DS induced a transient (at least 1 min) increase in spinal cord excitability and, compared to tonic stimulation, generated a more robust potentiation of the motor output evoked by single pulses applied to the spinal cord. When sub-threshold pulses were selectively applied to a cortical motor area, EMG responses from the contralateral leg were facilitated by the delivery of DS to the lumbosacral cord. Finally, based on motor-evoked responses, DS was linked to a greater amplitude of motor output shortly after a calibrated spinal cord contusion. CONCLUSION: Compared to traditional tonic waveforms, DS amplifies both spinal and cortico-spinal input aimed at spinal networks, thus significantly increasing the potential and accelerating the rate of functional recovery after a severe spinal lesion.

A digital anatomic investigation of the safe triangle areas for L1-5 percutaneous minimally invasive discectomy.

PURPOSE: To reconstruct the three-dimensional safe triangle areas at L1-5 based on the computed tomography digital data, analyze the safe scopes for the puncture location and angles, and provide anatomic references for percutaneous lumbar discectomy. METHODS: Computed tomography data from patients and control group were imported from the database and anatomical reference parameters were measured in Mimics software. The rebuilt model was rotated clockwise along the M-axis to measure the inscribed circle radius of the safe triangle at different angles. Based on the outer diameter of the largest cannula, the safe angles were calculated. The distances between points on the projection of safe triangle-inscribed circle and the upper lumbar spinous process were measured. Similarly, while the safe triangle was on the left side, the model was contra-rotated to measure all the parameters. RESULTS: There was no significant difference between the patient and control group in both the least distance between the selected anatomical reference locations and the safe triangle-inscribed circle radius at L4-5. According to the series which had a largest cannula of 2.5 mm, the safe puncture angles increased with the descending disc levels. The optimal angles were 40°-45° for L1-2, 45°-50° for L2-3, 50° for L3-4, and 55° for L4-5 separately. The differences between genders in the distances of paired reference points were significant. CONCLUSIONS: Individual safe localization of the percutaneous puncture could be obtained by analyzing the three-dimensional relationship between the puncture localization and anatomical landmarks.

BMSCs-Derived Exosomes Ameliorate Pain Via Abrogation of Aberrant Nerve Invasion in Subchondral Bone in Lumbar Facet Joint Osteoarthritis.

Lumbar facet joint osteoarthritis (LFJ OA) is regarded as one of the common causes of low back pain (LBP). The pathogenesis and underlying mechanism of this disease are largely unknown, there is still no effective disease-modifying therapy. This study aims to investigate the efficacy of exosomes derived from bone marrow mesenchymal stem cells (BMSCs) on the pathogenesis and behavioral signs of LBP in the LFJ OA mouse model. The pathogenetic change in cartilage and aberrant nerve invasion in the subchondral bone of LFJ in a mouse model after treatment with BMSC-exosomes was evaluated. BMSC-exosomes could relieve pain via abrogation of aberrant CGRP-positive nerve and abnormal H-type vessel formation in the subchondral bone of LFJ. Moreover, BMSC-exosomes attenuated cartilage degeneration and inhibited tartrate-resistant acid phosphatase expression and RANKL-RANK-TRAF6 signaling activation to facilitate subchondral bone remodeling. These results indicated that BMSC-exosomes could relive behavioral signs of LBP and pathological processes in LFJ OA. BMSC-exosomes have a prominent protective effect and might be a potential therapeutic option for the treatment of LFJ OA causing LBP. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:670-679, 2020.