Lumbosacral Nerve Roots Research Articles

MR neurography of lumbosacral nerve roots: Diagnostic value in chronic inflammatory demyelinating polyradiculoneuropathy and correlation with electrophysiological parameters

PurposeMR neurography(MRN) is an advanced imaging technique to visualize peripheral nerves. Our aim was to determine the value of morphological features of lumbosacral nerve roots on MRN in diagnosing chronic inflammatory demyelinating polyradiculoneuropathy(CIDP) and analyze their correlations with electrophysiological parameters. MethodsMRN of lumbosacral plexus was performed in 21 CIDP patients and 21 healthy volunteers. The cross-sectional areas(CSAs) and signal intensities(SI) of L3 to S1 nerve roots were measured and compared between two groups. Receiver operating characteristic(ROC) curves were plotted to assess the diagnostic accuracy. All patients also underwent nerve conduction studies. Correlations between CSAs and SI of lumbosacral nerve roots and electrophysiological parameters were analyzed. ResultsCompared with control group, CIDP patients showed significantly increased CSAs and SI from L3 to S1 nerve root (P < 0.001 and P < 0.05 respectively for all nerve roots). The CSAmean and SImean were 28.04 ± 8.55mm2, 1.314 ± 0.199 for patient group and 14.91 ± 2.36mm2,1.155 ± 0.094 for control group. ROC analysis revealed the best diagnostic accuracy for the CSAmean with an area under the curve of 0.968 and optimal cut-off value of 19.20 mm2. CSAs of L5 or S1 nerve root correlated positively with central latency and negatively with conduction velocity of tibial nerve. SI of L5 also had a positive correlation with latency of sural nerve. ConclusionsEvaluation of lumbosacral nerve roots on MRN in a quantitative manner may serve as an important tool to support the diagnosis of CIDP.

Thoracic 11-Lumbar 1 Laminoplasty for Resection of Conus Arteriovenous Malformation: 2-Dimensional Operative Video.

Conus medullaris spinal arteriovenous malformations are uniquely classified by the Spetzler classification. They possess a glomus (type II) nidus in either or both the intra- and extramedullary compartments, with multiple feeding arteries and niduses resulting in complex venous drainage patterns. These characteristics make resection of these lesions challenging, and these lesions are associated with a high risk for recurrence. This patient presented with a subarachnoid hemorrhage, and thorough imaging evaluation revealed a conus arteriovenous malformation. The patient underwent thoracic 11 to lumbar 1 laminoplasty for resection of the lesion. The arteriovenous malformation was circumdissected off the conus and lumbosacral nerve roots using sharp dissection and bipolar forceps. It was visualized both before and after resection with indocyanine green fluoroscopy. The patient tolerated the procedure well, and postoperative angiography demonstrated complete resection. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Use of Magnetic Resonance Neurography for Evaluating the Distribution and Patterns of Chronic Inflammatory Demyelinating Polyneuropathy.

ObjectiveTo evaluate the distribution and characteristics of peripheral nerve abnormalities in chronic inflammatory demyelinating polyneuropathy (CIDP) using magnetic resonance neurography (MRN) and to examine the diagnostic efficiency.Materials and MethodsThirty-one CIDP patients and 21 controls underwent MR scans. Three-dimensional sampling perfections with application-optimized contrasts using different flip-angle evolutions and T1-/T2- weighted turbo spin-echo sequences were performed for neurography of the brachial and lumbosacral (LS) plexus and cauda equina, respectively. Clinical data and scores of the inflammatory Rasch-built overall disability scale (I-RODS) in CIDP were obtained.ResultsThe bilateral extracranial vagus (n = 11), trigeminal (n = 12), and intercostal nerves (n = 10) were hypertrophic. Plexus hypertrophies were observed in the brachial plexus of 19 patients (61.3%) and in the LS plexus of 25 patients (80.6%). Patterns of hypertrophy included uniform hypertrophy (17 [54.8%] brachial plexuses and 21 [67.7%] LS plexuses), and multifocal fusiform hypertrophy (2 [6.5%] brachial plexuses and 4 [12.9%] LS plexuses) was present. Enlarged and/or contrast-enhanced cauda equina was found in 3 (9.7%) and 13 (41.9%) patients, respectively. Diameters of the brachial and LS nerve roots were significantly larger in CIDP than in controls (p < 0.001). The largest AUC was obtained for the L5 nerve. There were no significant differences in the course duration, I-RODS score, or diameter between patients with and without hypertrophy.ConclusionMRN is useful for the assessment of distribution and characteristics of the peripheral nerves in CIDP. Compared to other regions, LS plexus neurography is more sensitive for CIDP.

Up-regulation of heat shock protein 27 inhibits apoptosis in lumbosacral nerve root avulsion-induced neurons

Lumbosacral nerve root avulsion leads to widespread death of neurons in the anterior horn area of the injured spinal cord, which results in dysfunction in the lower extremities. Heat shock protein 27 (Hsp27) has been found to play cytoprotective roles under adverse conditions. However, the role of Hsp27 in neurons after lumbosacral nerve root avulsion is unknown. The aim of the present study was to investigate the effects and mechanism of action of Hsp27 on neurons after lumbosacral nerve root avulsion. It was found that Hsp27 expression was elevated in the anterior horn area of the injured spinal cord and the up-regulation of Hsp27 protected neurons against apoptosis after lumbosacral nerve root avulsion. In addition, Hsp27 plays an anti-apoptotic role by suppressing oxidative stress reactions. These findings indicated that Hsp27 may play a key role in resistance to lumbosacral nerve root avulsion-induced neuron apoptosis and may prove to be a potential strategy for improving prognosis after lumbosacral nerve root avulsion.

Computed Tomography−Guided Posterolateral Transsacral Ala Approach to Presacral L5 Schwannoma: Technical Note

Presacral schwannomas are rare benign tumors that may reach large size before becoming symptomatic. Total surgical removal has been considered the best treatment option. Tumors arising from the presacral area are commonly managed through anterior approaches, whereas posterior approaches are used for pure intrasacral tumors or large lesions with both intrasacral and presacral extension, alone or in combination with anterior approaches. We describe a quick and minimally invasive navigation-guided posterolateral approach to a right presacral L5 schwannoma. The lesion was microsurgically removed through high-speed drilling of the upper portion of the right sacral ala, under intraoperative neurophysiologic monitoring. The postoperative course was unremarkable, and the patient experienced improvement in his sensory disturbance. Postoperative magnetic resonance imaging and computed tomography scan showed the complete excision of the lesion and the removal of the upper sacral ala with preservation of the right L5-S1 articular complex. The histologic examination confirmed a schwannoma (World Health Organization grade I). The posterolateral transsacral ala approach may represent a minimally invasive option in the surgical management of presacral well-circumscribed benign tumors. Spinal navigation could be properly used to facilitate lesion exposure and to minimize the bone removal. The intraoperative neurophysiologic monitoring is an essential tool for the preservation of the lumbosacral nerve roots.

Quantitative assessment of diabetic amyotrophy using magnetic resonance neurography-a case-control analysis.

To quantitatively characterize diabetic amyotrophy (DA), or diabetic lumbosacral radiculoplexopathy, and compare with controls using magnetic resonance neurography (MRN). Forty controls and 23 DA cases were analyzed qualitatively and quantitatively. Cross-sectional areas (CSAs) of bilateral L3 through S2 lumbosacral nerve roots, femoral nerves, and sciatic nerves (proximal and distal measurements) were measured. A linear model was used to assess the nerve location and case/control effect on angle-corrected CSAs. Intra- and inter-reader analysis was performed using intraclass correlation (ICC). In DA cases, abnormalities of the lumbosacral nerve roots, sciatic, femoral, and obturator nerves were seen in 21/23, 16/23, 21/23, and 9/23, respectively. Denervation abnormalities of multiple abdominopelvic muscles were seen. Quantitatively, the CSA of all measured LS plexus nerve roots and bilateral femoral nerves were significantly larger in DA cases vs. controls by 45% (95% CI, (30%, 49%); p< 0.001). The ICC was moderate for inter-rater analysis = 0.547 (95% CI, 0.456-0.626) and excellent for intra-rater analysis = 0.90 (95% CI, 0.89-92). Multifocal neuromuscular lesions related to diabetic amyotrophy were qualitatively and quantitatively detected on MRN. Qualitative abnormalities distinguished cases from controls, and nerve CSAs of cases were significantly larger than those of controls. Therefore, MRN may be employed as a non-invasive diagnostic tool for the evaluation of diabetic amyotrophy. • Qualitative abnormalities of lumbosacral nerve roots, their peripheral branches, and muscles are seen in DA. • The lumbosacral nerve roots and their peripheral branches in diabetic amyotrophy cases are significantly larger in cross-sectional area than non-diabetic subjects by 45% (95 CI, 30%, 49%; p < 0.001). • The ICC was moderate for inter-rater analysis = 0.547 (95% CI, 0.456-0.626) and excellent for intra-rater analysis = 0.90 (95% CI, 0.89-92).

Protocol for the development of a core outcome set for cauda equina syndrome: systematic literature review, qualitative interviews, Delphi survey and consensus meeting

IntroductionCauda equina syndrome (CES) is a serious neurological condition most commonly due to compression of the lumbosacral nerve roots, which can result in significant disability. The evidence for acute intervention...

Diffusion tensor imaging of diabetic amyotrophy.

To qualitatively and quantitatively characterize the nerves of patients with diabetic amyotrophy (DA) using magnetic resonance neurography (MRN) with diffusion tensor imaging (DTI). Forty controls and 13 DA cases were analyzed. 1.5-Tesla and 3.0-Tesla MRN with DTI was used. Qualitative data from 13 patient records were recorded. Region of interest (ROI) measurements were taken of bilateral L3 through S2 lumbosacral nerve roots, femoral nerves, and sciatic nerves. An ANOVA and multiple linear regression analysis were performed. An intraclass correlation coefficient (ICC) was calculated between two readers. In DA cases, abnormalities of the lumbosacral nerve roots (n = 11 patients), sciatic (n = 10), femoral (n = 13), and obturator nerves (n = 4) were seen; denervation changes of the abdominopelvic muscles were also identified. Quantitatively, minimum and mean nerve signals on B600 were significantly less than controls (p < 0.001). Minimum and mean ADC values were significantly greater in cases than in controls (p < 0.001 and p = 0.002 respectively). Mean fractional anisotropy (FA) values were significantly lower in cases than in controls (p = 0.041). There were no significant differences in the minimum FA values between cases and controls. Minimum and mean ADCs correlated positively with highest recorded hemoglobin A1 (HbA1c) while controlling for sex, age, and BMI (β = 0.518, p < 0.001 and β = 0.302, p = 0.020 respectively). ICCs were 0.892 (B600), 0.717 (ADC), and 0.730 (FA). Neuromuscular lesions secondary to DA are qualitatively and quantitatively identified on MRN with DTI, and a positive correlation of ADC levels with serum HbA1c levels exists. Thus, MRN with DTI can be employed as a non-invasive diagnostic tool, if DA is suspected.

Anatomic measurement and clinical significance of the lumbosacral nerve roots

Anatomic measurement and clinical significance of the lumbosacral nerve roots

Protecting Surgeons' Fingers from Radiation Exposure during Lumbosacral Selective Nerve Root Block.

Introduction Fluoroscopy-guided selective nerve root block (SNRB) is useful for the diagnosis and treatment of nerve root pain. However, the procedure exposes the surgeon's hands to radiation. Therefore, the purpose of this randomized prospective study was to assess the radiation exposure per unit time of the surgeon's fingers during performance of a lumbosacral SNRB and to calculate the annual exposure time limits for four hand-protection methods. Methods We prospectively recruited patients scheduled for an SNRB and measured the radiation exposure using a ring-type passive radiation dosimetry device attached to the distal phalanx of the index finger of the hand performing the needle placement. Patients were randomly divided into the following four groups: a) the direct exposure group, b) the 0.03-mmPb glove group, c) the 0.25-mmPb glove group, and d) the forceps group (in which the needle was held using forceps such that the fingers did not enter the irradiation field). Results We recruited 40 consecutive patients (16 men and 24 women), with a mean age of 69 years. In all cases, SNRB was successfully performed without complications. The average exposure per hour for each of the four groups was as follows: 0.67 ± 0.56 mSv/s in the direct exposure group, 0.12 ± 0.07 mSv/s in the 0.03-mmPb glove group, 0.019 ± 0.02 mSv/s in the 0.25-mmPb glove group, and 0.001 ± 0.004 mSv/s in the forceps group (p < 0.01). The average annual exposure time limit was 12.4 min in the direct exposure group, 67.9 min in the 0.03-mmPb glove group, 7.5 h in the 0.25-mmPb glove group, and 5.0 days in the forceps group. Conclusions Using a radiation reduction glove or forceps greatly decreased the radiation exposure and increased the annual exposure time limit for SNRB.

Superior Gluteal Vein (SGV) Syndrome: An Intrapelvic Cause of Sciatica

Objective: The role of malformed or dilated branches of iliac vessels in causing pelvic pain and sciatica is not well understood. We describe cases of sciatica in which laparoscopy revealed compression of lumbosacral (LS) nerve roots by variant superior gluteal veins (SGVs). In demonstrating an improvement in symptoms after decompression, we identify this neurovascular conflict as a potential intrapelvic cause of sciatica.

Extradural Characteristics of the Origins of Lumbosacral Nerve Roots.

A great number of unsuccessful intervertebral herniated disk surgeries in the lumbosacral region have highlighted the importance of a comprehensive knowledge of the different types of nerve root anomalies. That knowledge gained by anatomical studies (and intraoperative findings) might contribute to better results. In our study we focused on intraspinal extradural lumbosacral nerve root anomalies and their possible role in radiculopathy. The study was performed on 43 cadavers within 24 hours after death (32 men and 11 women). Bodies were dissected in the prone position, and a laminectomy exposed the entire spinal canal for the bilateral examination of each spinal nerve root from its origin to its exit through the intervertebral foramen or sacral hiatus. Uncommon extradural features in the lumbosacral region were pursued and documented. The spinal dural sac was also opened, aimed at recognizing the normotyped, prefixed, or postfixed type of plexus. A total of 20.93% of anomalies of extradural lumbosacral nerve root origins were observed, with the normotyped plexus prevailing. We observed atypical spacing of exits of lumbosacral roots (four cases), two roots leaving one intervertebral foramen (one case), extradural anastomoses (two cases), and missing extradural nerve root courses (two cases). The results were differentiated according to the normotyped, prefixed, or postfixed plexus type. Results of similar studies dealing with anomalies of lumbosacral nerve roots were aimed at improving the results of herniated disk surgeries because ∼ 10% of misdiagnoses are related to ignorance of anatomical variability. Our observations may help explain the differences between the clinical picture and generally accepted anatomical standards.

The clinical features and outcome of scan-negative and scan-positive cases in suspected cauda equina syndrome: a retrospective study of 276 patients

BackgroundThe majority of patients presenting with suspected clinical cauda equina syndrome (CES) have no identifiable structural cause for their symptoms (‘scan-negative’ CES). Understanding these patients aids clinical differentiation and management in CES.MethodsA retrospective electronic note review was undertaken of patients presenting with suspected CES, defined as ≥ 1 of acute bladder, bowel, sexual dysfunction or saddle numbness, to a regional neurosciences centre. We investigated radiology, clinical features, psychiatric and functional disorder comorbidities and outcome of patients with ‘scan-negative’ CES and patients with MRI confirmed compression of the cauda equina (‘scan-positive’ CES).Results276 patients were seen over 16 months. There were three main radiologically defined patient groups: (1) ‘scan-positive’ CES (n = 78, mean age 48 years, 56% female), (2) ‘scan-negative’ CES without central canal stenosis but with lumbosacral nerve root compression not explaining the clinical presentation (n = 87, mean age 43 years, 68% female) and (3) ‘scan-negative’ CES without neural compromise (n = 104, mean age 42 years, 70% female). In the two ‘scan-negative’ groups (no neural compromise and nerve root compression), there were higher rates of functional disorders (37% and 29% vs. 9%), functional neurological disorders (12% and 11% vs 0%) and psychiatric comorbidity (53% and 40% vs 20%). On follow-up (mean 13–16 months), only 1 of the 191 patients with ‘scan-negative’ CES was diagnosed with an explanatory neurological disorder (transverse myelitis).ConclusionsThe data support a model in which scan-negative cauda equina syndrome arises as an end pathway of acute pain, sometimes with partly structural findings and vulnerability to functional disorders.

Movements of the lumbo-sacral nerve roots in the spinal canal induced by straight leg raising test: an anatomical study.

The pain involved in the herniated discs could be generated by some mobility of the nerve roots during straight leg raising (SLR). SLR produces some movement of nerves, but the magnitude of this displacement needs to be thorough, that is why we have investigated lumbo-sacral nerve root displacement in the spinal canal during the passive straight leg raise (SLR). Fourteen cadavers underwent laminectomy to mark the nerve roots of L2-S1 with lead balls. X-rays were taken during different movements imposed on the body: bilateral hip extension, left SLR then right and bilateral SLR. By superimposing these images two by two, the displacement of the nerve roots is quantified numerically during the various SLR maneuvers with respect to the reference position corresponding to the bilateral hip extension. The median range of the different nerve root movements ranged from 0.10 to 0.51cm (p < 0.05 except for the L2 root) when the left SLR is applied, from 0.26 to 0.48cm (p < 0.05) with the right SLR and from 0.30 to 0.65cm (p < 0.05) with a bilateral SLR. No statistically significant relationship was found between age and movement value. The lumbo-sacral nerve roots in the spinal canal region move statistically significantly in response to the clinically applied SLR test, except for L2 root during the left SLR. This movement is symmetric and greater when a bilateral SLR is applied. These anatomical results are correlated with those observed empirically in clinical practice.

Friday, September 28, 2018 1:00 PM–2:30 PM abstracts: a new look at imaging: 211. The feasibility of transcutaneous transabdominal stimulation of the lumbosacral nerve roots in lumbar spine surgery

BACKGROUND CONTEXT Intraoperative neuromonitoring during lumbar spine surgery has primarily relied on triggered and/or free-run electromyography (EMG) in mapping neural structures in the surgical field. Transcranial motor evoked potentials (MEPs) provide monitoring of the spinal cord, with nonspecific myotome activation following. Their application in lumbar procedures is increasingly being considered and utilized for cauda equina and nerve root monitoring. MEPs are more sensitive to detect a variety of spinal cord injury mechanisms, including ischemia, and, as such, have a higher sensitivity and specificity than stimulated electromyography (sEMG) with a higher postoperative predictive value for spinal cord deficits. The drawbacks of MEPs include the requirement for total intravenous anesthesia (TIVA), difficulty in achieving complete and reproducible baseline stimulation responses in relevant myotomes, lack of agreement on alarm criteria, and the potential for MEP-related injuries like tongue lacerations. Most importantly, MEPs are not validated in isolated lumbar applications, where the cauda equina and nerve roots, rather than the spinal cord, are at risk. There have, however, been several studies that have evaluated the utility of MEPs in XLIF. PURPOSE The purpose of this study was to assess the feasibility of using transabdominal muscle action potential (TMAPTM, NuVasive, Inc. San Diego, CA, USA) generation in lumbar fusions as an alternative to transcranial MEPs. This first analysis focuses on the feasibility and reproducibility of using this monitoring modality to activate individual lower-extremity myotomes. STUDY DESIGN/SETTING A prospective, multicenter, observational evaluation of the feasibility and utility of lower extremity nerve root compound muscle action potential monitoring in response to transabdominal stimulation was undertaken. Enrollment was completed at 15 US sites. Primary inclusion criteria included patients being at least 18 years of age who were undergoing extreme lateral interbody fusion (XLIF, NuVasive, Inc., San Diego, CA, USA) between L2-3 and L4-5, inclusive of L4-5. PATIENT SAMPLE A total of 335 patients were enrolled. Mean age of the patients was 64 years, 60% of patients were female, and patients had an average BMI of 30.6. A total of 524 levels of XLIF were treated in the 335 patients (mean, 1.6 per patient). The most common indication for surgery was spondylolisthesis (79%). OUTCOME MEASURES TMAP stimulation thresholds (mA) and myotome measurements (using a 30mV CMAP amplitude threshold) were taken prior to the initial incision at baseline, throughout the procedure at five minute intervals, and then again after closure. METHODS The technique for TMAP generation included the application of standard EMG bipolar pair recording electrodes on five myotomes per leg, one pair each on adductor magnus, vastus lateralis, vastus medialis, tibialis anterior, and biceps femoris. Stimulation was delivered transabdominally at approximately the superior end of the cauda equina. This stimulation pathway was selected to enable direct depolarization of the entire lumbosacral motor pathway as superior as possible to the surgical corridor, while remaining inferior to the spinal cord. The stimulation cathode was placed on the patient's posterior midline near the L1-2 disc space. The stimulation anode was placed on the patient's anterior midline superior to the umbilicus. For each TMAP stimulation, a series of pulses was applied with increasing stimulation intensity to identify the minimum stimulation intensity (threshold) required to elicit a compound muscle action potential (CMAP) for each individual myotome. RESULTS At baseline, all patients were stimulated transabdominally and a discrete CMAP response from at least one lower extremity myotome recorded. Out of a total of 3,350 myotomes (five bilateral myotomes per patient, per stimulation time point) stimulated at baseline, 3,255 (97.2%) yielded a CMAP in response to TMAP stimulation. At surgical closure, all patients had at least one myotome that was able to be activated with TMAP, with 94.6% of myotomes (3,169 myotomes) yielding a CMAP. Mean baseline stimulation threshold was 570mA (standard deviation (stdev), 192mA) with mean stimulation at closure of 599mA (stdev, 202mA), p CONCLUSIONS These data suggest that lower extremity nerve root monitoring can be accomplished reproducibly with TMAPs without the associated challenges or risk of traditional transcranial MEPs. While the TMAP technique using a novel stimulation application can supplement neural mapping via evoked EMG during XLIF, it also has potential utility in all lumbar surgical procedures where nerve roots are at risk. Subsequent analyses from this project will include injury detection and avoidance automation assessments.

Mechanical Traction for Lumbar Radicular Pain: Supine or Prone? A Randomized Controlled Trial.

The aim of the study was to compare the effects of mechanical lumbar traction either in the supine or in the prone position with conventional physical therapy (PT) in patients with chronic low back pain and lumbosacral nerve root involvement in terms of disability, pain, and mobility. Participants (N = 125) were randomly assigned to receive 15 sessions of PT with additional mechanical lumbar traction either in the supine position (supine traction group) or in the prone position (prone traction group) or only PT without traction (PT only group). Patients were assessed at baseline and at the end of the PT sessions in terms of disability, pain, and mobility. Disability was assessed using the modified Oswesty Disability Index; pain was assessed using a visual analog scale, and lumbar mobility was assessed using the modified lumbar Schober test. One hundred eighteen patients completed the trial. All groups improved significantly in the Oswesty Disability Index, visual analog scale, and modified lumbar Schober test (P < 0.05). In the between-group analysis, improvements of Oswesty Disability Index and visual analog scale were found significantly better in the prone traction group compared with the PT only group (adjusted P = 0.031 and 0.006, respectively). Addition of traction in the prone position to other modalities resulted in larger immediate improvements in terms of pain and disability, and the results suggest that when using traction, prone traction might be first choice. Further research is needed to confirm the benefits of lumbar traction in the prone position.

Induced lumbosacral radicular symptom referral patterns: a descriptive study

Background ContextLumbosacral radicular symptoms are commonly evaluated in clinical practice. Level-specific diagnosis is crucial for management. Clinical decisions are often made by correlating a patient's symptom distribution and imaging with sensory dermatomal maps. It is common for patients to describe non-dermatomal symptom patterns and for imaging to demonstrate pathology at levels not predicted by a dermatomal map. These observations suggest that the referred symptom distribution from lumbosacral nerve root provocation is different from dermatomal maps. This phenomenon has been demonstrated in the cervical spine but not in the lumbosacral spine. PurposeThe objective of this study was to characterize potential lumbosacral radicular symptom referral patterns induced during transforaminal epidural injections. Study Design/SettingThis is an observational descriptive study. Patient SampleThe patient sample included 71 consecutive patients with lumbosacral radicular pain undergoing lumbosacral transforaminal epidural injections at an outpatient interventional spine practice. Outcome MeasuresEach subject drew the location of provoked lumbosacral radicular symptoms on a pain diagram. Materials and MethodsSeventy-one consecutive patients undergoing 125 fluoroscopically guided lumbosacral transforaminal epidural injections at an outpatient interventional spine practice were included in the study. The described location of provoked symptoms was recorded (1) after final needle positioning, (2) after injection of up to 0.5 mL of contrast solution, and (3) after injection of up to a 1 mL test dose of 1% lidocaine. Each subject drew the location of provoked symptoms on a diagram. The provoked symptom diagrams for each lumbosacral segmental level were combined to create composite nerve root, level-specific, symptom referral pattern maps. ResultsOf the 125 injections, 87 provoked referred symptoms and were included in the analysis. Thirty-eight injections did not provoke referred pain symptoms and were excluded from further analysis. Four nerve roots were tested at L1 and eight were tested at L2. Because of the small number of subjects, composite diagrams and statistical analysis were not completed for these levels. Eleven nerve roots were analyzed at L3, 28 at L4, 34 at L5, and 11 at S1. Composite symptom referral pattern maps were created for levels L3, L4, L5, and S1. Although the symptom distribution occasionally followed the expected dermatomal maps, most often the referral was outside of the patterns expected for each level. The most common symptom referral pattern for levels L3–S1 was the buttock, the posterior thigh, and the posterior calf. ConclusionsThe level-specific provoked symptom distribution during lumbosacral transforaminal epidural injections is frequently different from that predicted by classic lumbosacral dermatomal maps. Referred pain to the buttock, the posterior thigh, or the posterior calf may come from L3, L4, L5, or S1 nerve root segmental irritation.

Quantitative Evaluation of Compressed L4-5 and S1 Nerve Roots of Lumbar Disc Herniation Patients by Diffusion Tensor Imaging and Fiber Tractography

To delineate fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of compressed nerve roots in patients with lumbar disc herniation by diffusion tensor imaging and fiber bundle tracing and investigate the relationship between FA and ADC values and Swiss Spinal Stenosis Questionnaire and visual analog scale scores. Twenty patients with lumbar disc herniation and 20 age- and sex-matched healthy volunteers were assessed using the Swiss Spinal Stenosis Questionnaire and visual analog scale. All subjects underwent conventional sagittal T1-weighted and T2-weighted magnetic resonance imaging, axial T2-weighted imaging, and diffusion tensor imaging and fiber tractography. In 20 patients with lumbar disc herniation, there were 31 nerve roots involved (9/31 L4, 15/31 L5, and 7/31 S1). Mean Swiss Spinal Stenosis Questionnaire scores of patients were 53.55% ± 11.91%, and mean visual analog scale scores were 5.96 ± 1.64. FA values of lumbar nerve roots were 0.332 ± 0.014 in healthy volunteers. FA values of compressed lumbar nerve roots were 0.251 ± 0.022, significantly lower than FA values of contralateral noncompressed nerve roots and lumbar nerve roots of healthy volunteers. ADC values of lumbar nerve roots were 1.763 ± 0.075 in healthy volunteers. ADC values of compressed lumbar nerve roots were 2.090 ± 0.078, significantly higher than ADC values of contralateral noncompressed nerve roots and lumbar nerve roots of healthy volunteers. Fiber tractography is capable of delineating microstructural changes of lumbosacral nerve roots, and radiculopathy in lumbar disc herniation is associated with significant changes in FA and ADC values.

Selective dorsal rhizotomy: current state of practice and the role of imaging.

Spastic diplegic cerebral palsy (CP) is the most common form of CP. A specific goal-oriented approach, tailored to the child, is essential to management in all forms of CP. Selective dorsal rhizotomy (SDR) is a neurosurgical procedure that permanently reduces lower limb spasticity in children with spastic diplegic CP. The current technique is performed through a single level laminectomy at the level of the conus and, with the aid of intraoperative electromyography (EMG), allows selective division of the afferent lumbosacral nerve roots. In carefully selected children, reduction in spasticity has positive effects on the growing child. SDR is associated with minimal complications and good long-term outcomes. This article describes the surgical technique and patient selection, including the importance of medical imaging, and discusses the long-term outcomes of SDR.

Neuroinflammation of the spinal cord and nerve roots in chronic radicular pain patients.

Numerous preclinical studies support the role of spinal neuroimmune activation in the pathogenesis of chronic pain, and targeting glia (eg, microglia/astrocyte)- or macrophage-mediated neuroinflammatory responses effectively prevents or reverses the establishment of persistent nocifensive behaviors in laboratory animals. However, thus far, the translation of those findings into novel treatments for clinical use has been hindered by the scarcity of data supporting the role of neuroinflammation in human pain. Here, we show that patients suffering from a common chronic pain disorder (lumbar radiculopathy), compared with healthy volunteers, exhibit elevated levels of the neuroinflammation marker 18 kDa translocator protein, in both the neuroforamina (containing dorsal root ganglion and nerve roots) and spinal cord. These elevations demonstrated a pattern of spatial specificity correlating with the patients' clinical presentation, as they were observed in the neuroforamen ipsilateral to the symptomatic leg (compared with both contralateral neuroforamen in the same patients as well as to healthy controls) and in the most caudal spinal cord segments, which are known to process sensory information from the lumbosacral nerve roots affected in these patients (compared with more superior segments). Furthermore, the neuroforaminal translocator protein signal was associated with responses to fluoroscopy-guided epidural steroid injections, supporting its role as an imaging marker of neuroinflammation, and highlighting the clinical significance of these observations. These results implicate immunoactivation at multiple levels of the nervous system as a potentially important and clinically relevant mechanism in human radicular pain, and suggest that therapies targeting immune cell activation may be beneficial for chronic pain patients.