Hyperemesis-induced Wernicke-Korsakoff Syndrome due to Hypergastrinemia during Long-term Treatment with Proton Pump Inhibitors.

We herein report a patient with Wernicke-Korsakoff syndrome (WKS) who had neither a history of alcoholism or of history of gastric surgery. A 56-year-old woman was transferred to our hospital because of the loss of consciousness and she was diagnosed to have Wernicke encephalopathy. She showed proton pump inhibitor-induced refractory hypergastrinemia with the subsequent development of hyperemesis and a vitamin B1 deficiency.

Do We Have Adequate Flexion-extension Radiographs for Evaluating Instability in Patients With Lumbar Spondylolisthesis?

STUDY DESIGN: A retrospective cohort study of consecutive patients. OBJECTIVE: To investigate whether adequate flexion-extension was acquired in standard functional radiographs in lumbar spondylolisthesis. SUMMARY OF BACKGROUND DATA: In lumbar spondylolisthesis, flexion-extension radiographs taken in the standing position are most commonly used to evaluate spinal instability. However, these functional radiographs occasionally depend on the patient's effort and cooperation, they can provide different results. METHODS: This study included 92 consecutive patients diagnosed with L4-5 degenerative lumbar spondylolisthesis. We analyzed the flexion-extension radiographs taken with the patient being led by the hand (LH) and those taken without LH (NLH). Sagittal translation (ST), segmental angulation (SA), posterior opening (PO), and lumbar lordosis (LL) were measured on functional radiographs taken in both tests. Then, ST, SA, PO, detection rate of instability, and LL observed in LH were compared with those observed in NLH. Furthermore, the correlation of the difference was evaluated between ST, lumbar angulation, and LL. RESULTS: A relative value of ST was 9.5% ±â€Š4.3% in LH and 5.6% ±â€Š3.3% in NLH, which differed significantly (P < 0.001). SA and PO were also significantly greater in LH than in NLH. The detection rate of instability was 71.7% in LH and 30.4% in NLH (P < 0.001). LL measurement on flexion showed 17.6°â€Š±â€Š13.5° in LH and 28.2°â€Š±â€Š12.2° in NLH, which differed significantly (P < 0.001). However, no significant difference was found in LL on extension between LH and NLH. There was a moderate correlation between the difference of ST, SA, PO, and LL on flexion. CONCLUSION: Flexion with physical assistance was useful for the detection of abnormal lumbar mobility. Taking radiation exposure into consideration, physical assistance such as using a table in front of a patient could lead the similar evaluation of the segmental instability. LEVEL OF EVIDENCE: 2.

Mid-term Clinical Results of Microendoscopic Decompression for Lumbar Foraminal Stenosis.

INTRODUCTION: There have been several reports on surgical techniques involving microendoscopy or percutaneous endoscopy for treating lumbar foraminal stenosis (LFS). However, no studies have assessed the mid-term clinical results of endoscopic techniques in spite of their relatively long history. In this study, we report 20 consecutive cases of LFS treated by our microendoscopic technique focusing on clinical results with a follow-up of at least two years. METHODS: Twenty consecutive cases of LFS treated with microendoscopic decompression were followed up at 1, 2, 6, and 12 months postoperatively and annually thereafter. The patients were 14 males and 6 females, and the mean age at the time of surgery was 64.7 years. The Japanese Orthopaedic Association (JOA) score was used as the clinical outcome index. RESULTS: Of the 20 patients, 16 were monitored successfully for more than 2 years. The follow-up rate was 80.0%, and the mean follow-up period was 66.3 months. The JOA score improved from 13.8 points before surgery to 24.6 points at final follow-up. Revision fusion surgeries were performed in two cases for LFS recurrence. CONCLUSIONS: The microendoscopic technique effectively treats LFS.

Analysis of Neuropathic Pain Using Magnetic Resonance Imaging T2 Mapping of Intervertebral Disc in Chronic Low Back Pain.

STUDY DESIGN: Cross sectional study. PURPOSE: The study aimed to analyze mechanisms underlying chronic low back pain (CLBP) using magnetic resonance imaging (MRI) T2 mapping of the intervertebral disc (IVD). OVERVIEW OF LITERATURE: MRI T2 mapping utilizes the T2 values for quantifying moisture content and collagen sequence breakdown. We previously used MRI T2 mapping for quantifying the extent of IVD degeneration (IVDD) and showed a correlation between the degeneration of the posterior annulus fibrosus (AF) and CLBP. METHODS: We enrolled 40 patients with CLBP (17 males, 23 females; mean age, 50.8±1.6 years; range, 22-60 years). IVDs were categorized as the anterior AF, nucleus pulposus (NP), and posterior AF, and T2 value for each disc was measured. T2 values, assessed using the Japanese neuropathic pain (NeP) screening questionnaire, of the NeP and nociceptive pain (NocP) groups were compared. RESULTS: T2 values of the NocP and NeP groups were 64.7±5.6 ms and 58.1±2.3 ms for the anterior AF; 67.0±4.6 ms and 59.6±2.1 ms for NP; and 70.7±4.6 ms and 51.0±1.2 ms for the posterior AF, respectively. T2 values for IVDD were significantly lower in the NeP group than those in the NocP group (p<0.01). CONCLUSIONS: The results indicate a correlation between the degeneration of posterior AF and NeP. MRI T2 mapping may be beneficial for detecting NeP caused by IVDD and can help formulate targeted analgesic therapies.

Comparison of Health-related Quality of Life Between Double-door Laminoplasty and Selective Laminoplasty for Degenerative Cervical Myelopathy, With a Minimum Follow-up of 5 Years.

STUDY DESIGN: A retrospective analysis of prospectively collected multicenter observational data. OBJECTIVE: The aim of this study was to compare the health-related quality of life (HR-QOL) of double-door laminoplasty (DDL) and selective laminoplasty (SL) in patients with degenerative cervical myelopathy (DCM) in two institutions, with a minimum follow-up of 5 years. SUMMARY OF BACKGROUND DATA: No study has compared DDL and SL regarding postoperative HR-QOL with a follow-up of more than 5 years. METHODS: One-hundred ninety patients who underwent DDL (n = 77) or SL (n = 113) participated in this study. Short-form 36 (SF-36), Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), Neck Disability Index (NDI), and visual analog scale (VAS) values were compared between the groups. RESULTS: Thirty-seven DDL and 52 SL patients were evaluated. The mean follow-up period was 8 years and the follow-up rate was 46.8%. No significant differences were found regarding age and JOA score at baseline. At the follow-up, there were no significant differences in SF-36, JOACMEQ, and VAS score, while the NDI score for headache and sleeping were higher in the SL group. After dividing the SL group into short and long SL subgroups, the long SL subgroup showed a significantly lower score in bodily pain in SF-36, lower and bladder function in JOACMEQ, and pain intensity, personal care, headaches, and sleeping in NDI compared with the other groups. CONCLUSION: No significant differences were found in SF-36, JOA score, and NDI, except for the NDI subscale of headache and sleeping. The subgroup analysis showed that the long SL group showed a decreased QOL compared with the short SL and DDL groups. LEVEL OF EVIDENCE: 3.

Differentiating spinal intradural-extramedullary schwannoma from meningioma using MRI T2 weighted images.

OBJECTIVE:: Prior studies advocate the subjective visual differences between meningioma and schwannoma on T2 weighted images, however objective measurement of signal intensity differences may be useful in certain cases. The aim of this study was to investigate whether an objective evaluation of SIs on T2 weighted images would be useful to differentiate spinal schwannomas from meningiomas. METHODS:: The patients with spinal MRIs demonstrating path proven and subsequently treated intradural extramedullary spinal tumors were selected between April 2008 and May 2017. Regions of interest (ROIs) were measured in the tumor and subcutaneous fat on the same image, and we calculated the SI ratio between tumor and fat ROIs. RESULTS:: Twenty patients each with meningioma and schwannoma were enrolled. The SI ratios of schwannomas were significantly higher than those of meningiomas (both researcher 1 and 2: p = 0.002). The areas under the curve by researchers 1 and 2 were 0.780. The cutoff value of SI ratio by both of researchers 1 and 2 to differentiate between schwannomas from meningiomas was 0.420 (sensitivity: 80.0%, specificity: 70.0-75.0%). CONCLUSION:: The SI ratio, calculated from the SIs of the tumor and fat on T2 weighted images, is useful for differentiating spinal schwannomas from meningiomas to obtain an accurate diagnosis. ADVANCES IN KNOWLEDGE:: Signal intensity ratio of the spinal tumor and fat on T2 weighted images is useful for differentiating schwannomas from meningiomas to obtain an accurate diagnosis.

The Difference in Gender Affects the Pathogenesis of Ligamentum Flavum Hypertrophy.

INTRODUCTION: Gender differences may play a role in the pathogenesis of lumbar spinal stenosis. However, few reports that discuss the effects of gender differences in ligamentum flavum (LF) hypertrophy have been published, and no study has investigated the relationship between LF thickness and the quantitative value of intervertebral disc (IVD) degeneration. This study aimed to investigate the impact of gender on the pathomechanisms underlying LF hypertrophy, focusing on the relationship among LF thickness, IVD degeneration, and age. METHODS: The subjects include 100 patients with low back pain and leg numbness, tingling, or pain. We measured LF thickness and the T2 values of IVDs using MR imaging and analyzed the relationship among LF thickness, T2 values of IVDs, and age. The interclass correlation coefficient (ICC) was calculated as the inter-rater reliability between the LF thickness values measured by two investigators. RESULTS: ICC was calculated for the two measurements of LF thickness (r = 0.923, 95% CI: 0.907-0.936). No statistically significant difference in the T2 values of IVDs was observed between females and males from L2/3 to L5/S. There were significantly negative linear correlations between LF thickness and the T2 values of IVDs at all levels, but this correlation was not observed in females at L4/5. There were significantly negative linear correlations between age and the T2 values of IVDs from L2/3 to L5/S for all patients, females, and males (r = 0.422-0.756). In addition, there were significantly positive linear correlations between age and LF thickness from L2/3 to L4/5 for all patients (r = 0.329-0.361) and females (r = 0.411-0.481). Correlations were not observed for males at all levels or for all patients at L5/S. CONCLUSIONS: The relationships identified among LF thickness, age, and IVD degeneration suggest that gender differences play a role in the pathogenesis of LF hypertrophy.

Suppression of Sympathetic Nerve Sprouting by Local Administration of an α-antagonist Around the Dorsal Root Ganglion in a Lumbar Radiculopathy Model.

STUDY DESIGN: Animal experimental study with intervention. OBJECTIVE: The purpose of this study was to elucidate whether local administration of an α-antagonist around the dorsal root ganglion (DRG) suppressed sympathetic nerve sprouting, from the acute to the chronic pain development phase, in a lumbar radiculopathy model using immunohistochemical methods. SUMMARY OF BACKGROUND DATA: The abnormal sympathetic-somatosensory interaction may underlie some forms of neuropathic pain. There were several reports suggesting α-antagonists are effective to treat neuropathic pain. However, its pathophysiological mechanisms remain obscure. METHODS: We used 70 male Sprague-Dawley rats. After root constriction (RC), rats received a series of three local injections of the nonselective α-antagonist phentolamine around the DRG for 3 days. There were three groups of rats: those that were injected from the day of surgery and those injected from day 4 and third group injected from day 11. The control rats were subjected to RC but equal-volume normal saline injections, and the naïve rats were not subjected to any surgical procedures. At the 14th postoperative day, the left L5 DRG was removed, embedded in paraffin, and sectioned. Sections were then immunostained with antibodies to tyrosine hydroxylase (TH). To quantify the extent of the presence of sympathetic nerve fibers, we counted TH-immunoreactive fibers in the DRG using a light microscope equipped with a micrometer graticule. We counted the squares of the graticule, which contained TH-immunoreactive fibers for each of five randomly selected sections of the DRG. RESULTS: In the naïve group, TH-immunoreactive fibers were scarce in the DRG. α-antagonist injections from postoperative day 0 and 4 suppressed sympathetic nerve sprouting compared with the control group. α-antagonist injections from postoperative day 11 had no suppressant effect compared with the control group. CONCLUSION: The α-antagonist administered around the DRG could suppress neural plastic changes in the early phase after nerve injury. LEVEL OF EVIDENCE: N/A.

Long-Term Outcome of Microendoscopic Diskectomy for Lumbar Disk Herniation. A Clinical Study of Consecutive 112 Cases with More than 5-Year Follow-Up.

Background Clinical results and recurrence rate after microendoscopic diskectomy (MED) with long-term follow-up is still unclear, in spite of its relatively long history. Materials and Methods A total of 112 who underwent MED participated in this study. Operative time, blood loss, serum C-reactive protein (CRP), creatine kinase (CK), and visual analog scale (VAS) were evaluated as indexes of surgical invasiveness. The 36-Item Short Form Survey Instrument (SF-36), Japanese Orthopaedic Association (JOA) score, patient satisfaction, and recurrence were also evaluated with a follow-up of at least 5 years. Results The mean operative time was 86.7 minutes, and the mean blood loss was 35.7 mL. The mean CRP on postoperative day 3 and CK on the first postoperative day was 0.72 mg/dL and 224.6 IU/L, respectively, and VAS to assess surgical site pain on the first postoperative day was 24.9 mm on average. The improvement rate in the JOA score was 68.7%. The physical component summary of SF-36 in norm-based scoring was improved from 23.4 to 48.6. Overall, 90.8% of patients evaluated their response to the surgery as extremely satisfied or satisfied. The recurrence rate was 10.5%, and reoperation was performed in 7.9% of patients. Conclusions MED is a technique that offers both reduced invasiveness and good long-term clinical results.

Sympathectomy and Sympathetic Blockade Reduce Pain Behavior Via Alpha-2 Adrenoceptor of the Dorsal Root Ganglion Neurons in a Lumbar Radiculopathy Model.

STUDY DESIGN: Animal experimental study with intervention. OBJECTIVE: We investigated whether sympathectomy and pharmacological sympathetic blockade reduced pain behavior and reversed adrenoceptor mRNA expression of the dorsal root ganglion (DRG) in a lumbar radiculopathy model. SUMMARY OF BACKGROUND DATA: The abnormal sympathetic-somatosensory interaction may underlie some forms of neuropathic pain. There are several reports that sympathectomy and pharmacological sympathetic blockades are often effective to treat neuropathic pain. However, its pathophysiological mechanisms remain obscure. METHODS: We used 91 male Sprague-Dawley rats. Just after root constriction (RC), the rats underwent sympathectomy or received 3 local injections of subtype-specific α-adrenergic receptor antagonists around the DRG. We evaluated the analgesic effects of sympathectomy and sympathetic blockade using behaviors indicative mechanical allodynia and thermal hyperalgesia. We estimated the mRNA expression levels of the DRG adrenoceptor subtypes using real time reverse transcription polymerase chain reaction. RESULTS: Sympathectomy and α2-antagonist significantly reduced the mechanical allodynia and thermal hyperalgesia after RC. Real time reverse transcription polymerase chain reaction analysis indicated that sympathectomy possibly reversed α2A- and α2B-adrenoceptors mRNA overexpression in the DRG after RC. CONCLUSION: We considered that pain behaviors of neuropathic pain are due, at least in part, to enhanced sympathetic noradrenergic transmission within the DRG. Suppression of sympathetic activity by reducing adrenergic release, α2-adrenoceptor stimulation, and/or α2-adrenoceptor upregulation in the DRG may relieve neuropathic pain. LEVEL OF EVIDENCE: 3.

Mapping occipital bone thickness using computed tomography for safe screw placement.

OBJECT Safe and effective insertion of occipital bone screws requires morphological analysis of the occipital bone, which is poorly documented in the literature. The authors of this study present morphological data for determining the area of screw placement for optimal internal fixation. METHODS The subjects of this institutional review board-approved retrospective study were 105 individuals without head and neck disease who underwent CT imaging at the authors' hospital. There were 55 males and 50 females, with a mean age of 57.1 years (range 20-91 years). Measurements using CT were taken according to a matrix of 55 points following a grid with 1-cm spacing based on the external occipital protuberance (EOP). RESULTS The maximum thickness of the occipital bone was at the level of the EOP at 16.4 mm. Areas with thicknesses > 8 mm were more frequent at the EOP and up to 2 cm in all directions, as well as up to 1 cm in all directions at a height of 1 cm inferiorly, and up to 3 cm from the EOP inferiorly. The male group tended to have a thicker occipital bone than the female group, and the differences were significant around the EOP. The ratio of the trabecular bone to the occipital bone thickness was > 30% in the central region. At positions more than 2 cm laterally, the ratio was < 15%, and the ratio gradually decreased further laterally. CONCLUSIONS Screws that are 8 mm long can be placed in the area extending 2 cm laterally from the EOP at the level of the superior nuchal line and approximately 3 cm inferior to the center. These results suggest that it may be possible to effectively insert a screw over a wider area than the conventional reference range.

Analysis of chronic low back pain with magnetic resonance imaging T2 mapping of lumbar intervertebral disc.

BACKGROUND: Magnetic resonance imaging (MRI) T2 mapping utilizes the T2 values for quantification of moisture content and collagen sequence breakdown. Recently, attempts at quantification of lumbar disc degeneration through MRI T2 mapping have been reported. We conducted an analysis of the relationship between T2 values of degenerated intervertebral discs (IVD) and chronic low back pain (CLBP). METHODS: The subjects who had CLBP comprised 28 patients (15 male, 13 female; mean age 48.9 ± 9.6 years; range 22-60 years). All subjects underwent MRI and filled out the low back pain visual analog scale (VAS) and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The disc was divided into the anterior annulus fibrosus (AF), the nucleus pulposus (NP), and the posterior AF, and each T2 value was measured. This study involved 25 asymptomatic control participants matched with the CLBP group subjects for gender and age (13 male, 12 female; mean age 43.8 ± 14.5 years; range 23-60 years). These subjects had no low back pain, and constituted the control group. RESULTS: T2 values for IVD tended to be lower in the CLBP group than in the control group, and these values were significantly different within the posterior AF. The correlation coefficients between the VAS scores and T2 values of anterior AF, NP and posterior AF were r = 0.30, -0.15 and -0.50. The correlation coefficient between the JOABPEQ scores (low back pain) and T2 values of anterior AF, NP and posterior AF were r = -0.0041, 0.11 and 0.42. Similarly, the JOABPEQ scores (lumbar function) were r = -0.22, -0.12 and 0.57. CONCLUSIONS: The results indicated a correlation between posterior AF degeneration and CLBP. This study suggests that MRI T2 mapping could be used as a quantitative method for diagnosing discogenic pain.

Evaluation of sciatic nerve function after ultrasonic and electrocautery muscle dissection: an electromyographic study.

BACKGROUND: Minimally invasive surgery has been developed with various innovative surgical tools. Ultrasonic (US) blades have been introduced as an alternative to conventional electrocautery (EC) monopolar device. The purpose of the present study was to evaluate the effects of surgical devices used for muscle dissection close to peripheral nerves on motor nerve function using electromyographic (EMG) recordings. MATERIALS AND METHODS: A total of 24 rats were used in this study. The rats were assigned to the following three groups: Control (n = 8), EC (n = 8), and US (n = 8). A stimulus electrode was placed under the sciatic nerve at a sciatic notch. A pair of recording electrodes was implanted into the midbelly regions of the gastrocnemius muscle. To evoke compound muscle action potentials (CMAPs), 3-V stimuli with 0.3-ms duration were applied to the sciatic nerve at a frequency of 1 Hz. After the recording of the baseline, a monopolar surgical device (EC or US) was applied to cut the muscle 10 mm in length and 2 mm away on both sides of the sciatic nerve. Amplitude and latency of the evoked CMAPs were measured. CMAPs were monitored until 3 hours after the device application. RESULTS: The EC device caused a marked drop in the amplitude of CMAP with no recovery at the end of the experiment. In the US group, the amplitude of CMAP was stable and constant CMAP over 3 hours, similar to the control group could be measured. In all three groups, the latency of CMAP showed no significant changes through the experiment. CONCLUSION: The study showed that the EC device resulted in injury to several motor units in the sciatic nerve. The US device may be a safe tool for muscle dissection around peripheral nerves.

Transient receptor potential ankyrin 1 in spinal cord dorsal horn is involved in neuropathic pain in nerve root constriction rats.

BACKGROUND: Lumbar radicular pain is categorized as a type of neuropathic pain, but its pathophysiological mechanisms are not fully understood. The substantia gelatinosa (SG) in the spinal cord dorsal horn receives primary afferent inputs and is considered to be a therapeutic target for treating neuropathic pain. In vivo patch-clamp recording is a useful procedure for analyzing the functional properties of synaptic transmission in SG neurons. Transient receptor potential ankyrin 1 (TRPA1) has been widely identified in the central and peripheral nervous systems, such as in the peripheral nociceptor, dorsal root ganglion, and spinal cord dorsal horn and is involved in synaptic transmission of pain. However, its functional role and mechanism of pain transmission in the spinal cord dorsal horn are not well understood. The purpose of this study was to use in vivo patch-clamp analysis to examine changes in the excitatory synaptic transmission of SG neurons treated with TRPA1 antagonist and to clarify the potential role of TRPA1 in the rat spinal cord dorsal horn. RESULTS: The rats with root constriction (RC) showed mechanical hypersensitivity, hyperalgesia, and thermal hyperalgesia. In addition, pin pricks elicited pain-related behavior even in the sham and naïve rats. These pain-related behaviors were significantly attenuated by intrathecal injection of a TRPA1 antagonist. The degrees of intrathecal injection efficacy were equivalent among the 3 groups (RC, sham, and naïve groups). In an electrophysiological study, the frequencies and amplitudes of excitatory postsynaptic currents (EPSCs) were significantly increased in the RC rats compared with those in the sham and naïve rats. Spontaneous EPSCs and evoked-EPSCs by non-noxious and noxious stimuli were significantly decreased by TRPA1 antagonist. As in the behavioral study, there were no statistically significant differences among the 3 groups. CONCLUSION: These data showed that the TRPA1 antagonist had an inhibitory effect on mechanical hypersensitivity and hyperalgesia as well as on physiological pain transmission in the spinal cord dorsal horn. This suggests that TRPA1 is consistently involved in excitatory synaptic transmission even in the physiological state and has a role in coordinating pain transmission.

Atypical fungal vertebral osteomyelitis in a tsunami survivor of the Great East Japan Earthquake.

STUDY DESIGN: Case report. OBJECTIVE: We report a rare case of fungal vertebral osteomyelitis in a tsunami survivor of the Great East Japan Earthquake. SUMMARY OF BACKGROUND DATA: Fungal vertebral osteomyelitis due to Scedosporium apiospermum (S. apiospermum) is extremely rare. We describe the case of a 45-year-old male who developed vertebral osteomyelitis by S. apiospermum 1 month after near drowning in the huge tsunami after the Great East Japan Earthquake. METHODS: The patient was treated with a combination of percutaneous posterolateral endoscopic debridement and antifungal therapy. The case was evaluated with radiography and computed tomography, and his white blood cell count and C-reactive protein level in serum were measured 20 months after initiation of treatment. RESULTS: The patient had no low back pain and both white blood cell count and C-reactive protein had remained normal. Radiographs and computed tomography of lumbar spine demonstrated sclerotic change of endplates and spur formation bridging the L3 and L4 vertebral bodies. CONCLUSION: We report a rare case of the fungal vertebral osteomyelitis caused by S. apiospermum. If a patient develops severe back pain after a near-drowning episode in dirty water such as a swamp or a river, the clinician should be suspicious of the possibility of fungal spondylitis by S. apiospermum.

Microendoscopy-assisted muscle-preserving interlaminar decompression for lumbar spinal stenosis: clinical results of consecutive 105 cases with more than 3-year follow-up.

STUDY DESIGN: A retrospective review of data collected prospectively on patients who underwent microendoscopy-assisted muscle-preserving interlaminar decompression (MILD) for lumbar spinal stenosis. OBJECTIVE: To evaluate the clinical results including surgical invasiveness and reduction rate of facet joint with a follow-up of more than 3 years. SUMMARY OF BACKGROUND DATA: Hatta et al reported microscopic posterior decompression procedure, MILD for lumbar spinal stenosis with reference to the cervical central approach put forth by Shiraishi. Mikami et al applied spinal microendoscopy to MILD procedure (microendoscopy-assisted MILD). METHODS: One hundred five consecutive patients, who underwent microendoscopy-assisted MILD, participated in this study. Operative time, blood loss, visual analogue scale (VAS), serum creatine kinase and C-reactive protein, surgical complications, reduction rate of the facet joint, Japanese Orthopaedic Association score, and Short-Form 36 were evaluated. RESULTS: The operative time was 99.3 minutes and the intraoperative bleeding was 15.7 mL on average. The mean VAS score to assess surgical site pain was 20.6 mm on postoperative day 1. The mean serum creatine kinase on postoperative day 1 and C-reactive protein on postoperative day 3 were 145.4 IU/L and 2.7 mg/dL, respectively. Surgical complications were identified in 2 cases, cauda equina injury and dural tear. The mean reduction rate of the facet joint was 3%. The follow-up rate was 83.3% and the mean follow-up period was 52.7 months. The Japanese Orthopaedic Association score improved significantly from 14.8 to 23.7 points on average. Significant improvements in Short-Form 36 were observed in all subscales except in General Health. Revision surgical procedures were performed in 8 cases at the operated level including 4 of juxtafacet cyst, 3 of disc herniation, and 1 of insufficient decompression. CONCLUSION: Microendoscopy-assisted MILD is a minimally invasive procedure and favorable clinical results can be expected for lumbar spinal stenosis. LEVEL OF EVIDENCE: 4.

Microendoscopic discectomy in athletes.

BACKGROUND: Management of lumbar disc herniation in athletes is challenging because a prolonged period of postoperative rehabilitation prevents the athlete from participating in sporting activity, resulting in loss of competitive form. No study reporting the clinical results of microendoscopic discectomy (MED) in athletes was identified in a literature search through PubMed, in spite of the relatively long history of this treatment. The objective of this study was to evaluate the efficacy of MED for athletes, focusing on their ability to quickly resume their sports activity. METHODS: Twenty-five competitive athletes, who underwent MED participated in this study. The level of sporting activity patients were capable of achieving, and the time until complete return to competitive level were assessed. The Japanese Orthopaedic Association (JOA) score and short form 36 (SF-36) were also evaluated. RESULTS: Two patients did not return to sporting activity for reasons unrelated to the lumbar diseases. Among the remaining 23 cases, 19 (82.6 %) successfully returned to their original levels of sporting activity. One patient (4.4 %) could not return to his pre-injury level of sporting activity because of residual pain. He changed his field from a high school sports team to a low-level sports society. The mean period until complete return to competition was 10.8 weeks (range 5-16 weeks). Three patients (13.0 %) could not resume sporting activity because of residual pain. The mean improvement rate of JOA score at final follow-up was 80.4 %. Significant improvements in SF-36 were observed in all subscales except in general health perceptions. CONCLUSIONS: MED is a well-balanced technique which offers a high probability of return and an early return to the same level of sporting activity, both of which are optimal aims in treatment of athletes with lumbar disc herniation.

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.

Does norepinephrine influence pain behavior mediated by dorsal root ganglia?: a pilot study.

BACKGROUND: Postganglionic neurons in the sympathetic nervous system reportedly are involved in lumbar radicular pain and release norepinephrine (NE), a neurotransmitter. Increased numbers of sympathetic nerve fibers have been found in dorsal root ganglion (DRG) neurons in a root constriction model. Whether this is a reasonable model for pain, however, is unclear QUESTIONS/PURPOSES: We asked whether: (1) painful behaviors occurred in the root constriction model; (2) NE enhanced the excitability of DRG neurons in the root constriction model; and (3) which adrenoceptors were related to the mediation of the NE effects. METHODS: The L5 root was sutured proximal to the DRG as the root constriction model. Behavioral tests were performed until 28 days after surgery. At 10 to 14 days after the root constriction, DRG neurons were quickly excised and digested with collagenase for electrophysiologic studies. Action potentials were recorded from single DRG neurons using a whole-cell patch clamp technique. NE (10 µmol/L) was directly applied to the DRG neurons. The adrenergic sensitivity was examined in combination with antagonists. RESULTS: The rats with root constriction exhibited painful behavior. NE increased the excitability of DRG neurons in the root constriction model. The effects of NE were inhibited by pretreatment with an α-antagonist and α(2)-antagonist but not an α(1)-antagonist. CONCLUSIONS: Our observations suggest NE plays an important role in generating lumbar radicular pain mainly via α(2)-adrenoceptors. CLINICAL RELEVANCE: An α(2)-antagonist may be an appropriate agent for trials to treat lumbar radicular pain.

Changes in synaptic transmission of substantia gelatinosa neurons in a rat model of lumbar radicular pain revealed by in vivo patch-clamp recording.

Little is known about the pathophysiological mechanisms of radicular pain. We investigated changes in synaptic transmission of substantia gelatinosa (SG) neurons after an injury to the L5 nerve root using in vivo patch-clamp recording. A total of 141 SG neurons were recorded at L4 and L5 segmental levels of the spinal cord in root constriction rats and sham-operated control rats. At L4 and L5 segmental levels, SG neurons without a receptive field were observed only in root constriction rats, and the frequencies of spontaneous action potential firings in SG neurons were higher in the root constriction group than in the control group. At the L5 segmental level, the frequencies and amplitudes of spontaneous excitatory postsynaptic currents (EPSCs) as well as the proportion of multireceptive neurons among SG neurons was higher in the root constriction group than in the control group. At the L4 segmental level, the frequencies and amplitudes of spontaneous EPSCs were increased in the root constriction group, but the proportions of cell types did not change. The mean amplitudes of EPSCs evoked by mechanical stimuli at L4 and L5 segmental levels were larger in the root constriction group than in the control group. The results indicated that injuring the nerve root led to characteristic excitatory synaptic transmission in SG neurons at each segmental level and changed sensory processing in SG neurons at the segment to which the injured nerve projected. These changes could lead to spontaneous pain, mechanical allodynia, and hyperalgesia contributing to the pathogenesis of radicular pain.