Effects of arterial ischemia and venous congestion on the lumbar nerve root in dogs

Lumbar Spinal Stenosis and Minimally Invasive Lumbar Decompression: A Narrative Review

Background

Lumbar spinal stenosis (LSS) is a common pain condition that causes lumbar back pain, radiating leg pain, and possible functional impairment. MILD is an emerging minimally invasive treatment for LSS. It is an image-guided percutaneous procedure designed to debulk hypertrophied ligamentum flavum. However, the exact short- and long-term efficacy, safety profile, indication criteria, and certain procedure details reported in medical literature vary.

Objective

This narrative review was to elucidate efficacy, safety profile, certain procedure details, advantages, and limitations of MILD.

Study Design

This is a narrative review.

Setting

All included articles are clinic trials including analytic studies and descriptive studies.

Methods

PubMed, Cochrane Library, and Scopus were searched. Only clinical trials of MILD procedure were included. Information of indications, contraindications, VAS scores, ODI scores, effective rate, efficacy durations, and certain procedure details was focused on.

Results

According to the literature, for the MILD procedure, the VAS score could be reduced from a pre-treatment level of 6.3-9.6 to a post-treatment level of 2.3-5.8. The ODI score could be reduced from a pre-treatment level of 38.8-55.3 to a post-treatment level of 27.4-39.8. The effective rate of the MILD procedure was reported to be 57.1%-88%. A 2-year postoperative stability of efficacy was also supported. One RCT study testified superior efficacy of MILD over epidural steroid injection.

Limitations

There is few high-quality literature in the review. Moreover, the long-term efficacy of MILD cannot be revealed according to the current literature.

Conclusion

Based on the reviewed literature, MILD is an effective and safe procedure. MILD can reduce pain intensity and improve functional status significantly. Therefore, it is a preferable option for LSS patients who failed conservative treatments, but not for those who require immediate invasive decompression surgery.

Impact of Sarcopenia on Percutaneous Epidural Balloon Neuroplasty in Patients with Lumbar Spinal Stenosis: A Retrospective Analysis

Background and Objectives: With the aging population, the incidence of degenerative lumbar spinal stenosis (LSS) is increasing. Sarcopenia is an age-related muscular decrease. Although epidural balloon neuroplasty is effective in patients with LSS refractory to conventional treatments, its effect has not been assessed in patients with sarcopenia. Therefore, this study evaluated the effect of epidural balloon neuroplasty in patients with LSS and sarcopenia. Materials and Methods: This retrospective study reviewed the following details from the electronic medical records: patient characteristics, including sex, age, body mass index, diabetes, hypertension, stenosis grading, pain duration, location, pain intensity, and medications. Back and leg pain intensity was evaluated before and after the procedure at one, three, and six months during the follow-up period. A generalized estimating equations model was used at six months follow-up. Patients were divided into sarcopenia and non-sarcopenia groups using the cross-sectional area of the psoas muscle at the level of L3 on magnetic resonance imaging. Results: A total of 477 patients were included (sarcopenia group: 314 patients, 65.8%; non-sarcopenia group: 163 patients, 34.2%). Age, sex, body mass index, and medication quantification scale III were statistically different between both groups. The generalized estimating equations analyses-with unadjusted and adjusted estimation-revealed a significantly reduced pain intensity after the procedure compared to the baseline in both groups. The difference in pain intensity between both groups was not statistically different. Conclusions: Percutaneous epidural balloon neuroplasty may be considered for patients with chronic lumbar LSS regardless of accompanying sarcopenia.

Robotic first rib resection for thoracic outlet syndrome

Robotic resection of the “offending portion” of the first rib in patients with thoracic outlet syndrome (TOS) has been associated with excellent results. The results have been due to (I) a better understanding of the pathogenesis of TOS, and (II) the technical advantages of the robotic platform. This article outlines the recent understanding of the pathogenesis of TOS, and reports the experience with robotic resection of the “offending portion” of the first rib in patients with neurogenic and venous TOS. Patients diagnosed with TOS underwent robotic first rib resection. Diagnosis of TOS was made by magnetic resonance angiography (MRA). On a thoracoscopic platform, the robot was used to dissect the “offending portion” of the first rib. A total of 162 patients underwent robotic first rib resection. Eighty-three patients underwent robotic first rib resection for Paget-Schroetter syndrome (PSS) (venous TOS). There were 49 men and 34 women. Mean age was 24±8.5 years. Operative time was 127.6±20.8 minutes. Median hospitalization was 4 days. There were no surgical complications, neurovascular injuries, or mortality. At a median follow-up of 24 months, all patients had an open subclavian vein (SV) for a patency rate of 100%. Seventy-nine patients underwent robotic first rib resection for neurologic symptoms of the upper extremity (neurogenic TOS). There were 29 men and 50 women. Mean age was 34±9.5 years. Operative time was 87.6±10.8 minutes. There were no intraoperative complications. Hospital stay ranged from 2–4 days with a median hospitalization of 3 days. There were no neurovascular complications. There was no mortality. In patients with neurogenic symptoms, Quick DASH Scores (mean ± SEM) decreased from 60.3±2.1 preoperatively to 5±2.3 in the immediate postoperative period, and 3.5±1.1 at 6 months (P<0.0001). Immediate relief of symptoms was seen in 71/79 (91%) patients. Persistent paresthesia was seen in 9/79 (9%) immediately postop and 3/79 (3.8%) patients at 6 months. Following the appropriate identification of the “offending portion” of the first rib which results in compression of the SV at its junction with the innominate vein by MRA, robotic resection of the “offending portion” of the first rib allows is associated with excellent results.

Imaging and histopathologic features of reversible nerve root and peripheral nerve edema secondary to disc herniation in a cat

Nerve root enlargement with increased contrast uptake has been reported in dogs and humans secondary to nerve root compression. In cats, nerve root enlargement and contrast uptake only have been reported in association with inflammatory and neoplastic diseases, but not as a sequela to nerve root compression. An 8‐year‐old oriental short hair cat was presented with acute neurologic deficits consistent with left‐sided sciatic nerve deficit and possible L6‐S1 myelopathy. Magnetic resonance imaging (MRI) was performed and identified compression of the cauda equina and L7 nerve root associated with intervertebral disc herniation (IVDH) at L6‐L7 as well as widespread sciatic nerve enlargement with moderate rim enhancement. A hemilaminectomy was performed to evacuate herniated disc material. The nerve root was biopsied and submitted for histological evaluation. Interstitial nerve edema was diagnosed. Follow‐up MRI 3 months postoperatively showed complete remission of the changes. Nerve root thickening together with contrast enhancement may represent nerve edema in cats secondary to IVDH.

Vascular compromise in a torsed transposed ulnar nerve case in support of intravenous contrast administration

Nerve torsion is a recognized etiology in brachial and peripheral neuropathy. Vascular compromise of peripheral nerves is uncommon given their unique vascular supply. Preoperative imaging diagnosis of nerve torsion and vascular compromise can be made in some cases, which impacts treatment. We present a previously unreported case of long segment torsion and vascular compromise of the ulnar nerve following anterior subcutaneous transposition with a description of the imaging findings based on the unique structure of the nerve and the presence of a blood nerve barrier (BNB) and a discussion of the potential vulnerability of a transposed and torsed nerve.

Computed Tomographic Measures of Funnel-Shaped Lumbar Vertebral Canal and Articular Process Dysplasia Malformations Differ Between German Shepherd and Belgian Malinois Military Working Dogs

Researchers who study the selection and breeding program criteria for military working dogs aim to help maximize the years of active duty service. Computed tomographic (CT) quantitative phenotyping has been previously described as a method for supporting these research studies. Funnel-shaped lumbar vertebral foramen malformations have been previously described in Labrador retriever military working dogs and proposed to be risk factors for impaired arterial perfusion of nerve tissues during exercise. Articular process dysplasia malformations have been previously described in varying dog breeds and proposed to be risk factors for articular process degenerative joint disease and vertebral foramen stenosis. Aims of this retrospective, cross-sectional study were to describe quantitative CT phenotyping methods for characterizing funnel-shaped lumbar vertebral foramina and articular process dysplasia malformations and to apply these methods in a comparison between groups of German shepherd and Belgian Malinois military working dogs. A military working dog hospital's database was searched for German shepherd and Belgian Malinois dogs aged <6 years that had CT scans of the lumbosacral region during the period of 2008–2016. Observers unaware of CT findings recorded available clinical data for each of the dogs. An observer unaware of clinical data recorded CT measures of funnel-shaped lumbar vertebral foramina and articular process dysplasia malformations for each of dogs and each of the lumbar vertebrae that were available in the scans. A total of 59 dogs were sampled: 41 German shepherd and 18 Belgian Malinois. Articular process dysplasia and funnel-shaped vertebral foramen phenotypic traits were present in both breeds in this sample, with the frequency and quantitative measure of these traits being greater in German shepherd dogs and heavier dogs. Lower weight dogs had a lesser degree of a funnel-shaped foramen at all sampled vertebral locations. A consistent relationship between articular process dysplasia measures and body weight was not seen. Computed tomography measures of funnel shaped vertebral foramina were greater in German shepherd vs. Belgian Malinois dogs at the L7 vertebra (P < 0.01). The CT measures of cranial articular process dysplasia were greater in German shepherd vs. Belgian Malinois dogs at the L4 (P < 0.01) and L5 (P < 0.05) vertebrae.

Surgical Intervention for Cauda Equina Syndrome in the Second and Third Trimesters of Pregnancy: A Report of Three Cases

CASE

Low back pain affects >50% of pregnant women. However, cauda equina syndrome (CES) during pregnancy is rare. Because a delay in treatment increases the risk of irreversible neurologic damage, acute onset is regarded as a surgical emergency. We describe 3 cases of CES in pregnant women at 24, 27, and 30 weeks' gestation, respectively.

CONCLUSION

All 3 of the patients underwent surgical decompression in the prone position under general anesthesia with continuous external monitoring of the fetal heart rate. Intraoperative findings were noteworthy for epidural venous plexus engorgement in 2 of the patients. There were no complications for the patients or the fetuses, and all 3 of the patients had postoperative resolution of the neurologic symptoms.

Combined epidural adhesiolysis and balloon decompression can be effective in intractable lumbar spinal stenosis patients unresponsive to previous epidural adhesiolysis

Moderate evidence exists regarding percutaneous epidural adhesiolysis (PEA) being an effective treatment for lumbar spinal stenosis (LSS). Although PEA is successfully performed using balloon-less epidural catheters, many patients with severe adhesions cannot obtain satisfactory results. Combined treatment with balloon-inflatable catheters for PEA and balloon decompression recently demonstrated sufficient pain relief and functional improvement in patients with intractable LSS. We compared the effects of PEA and balloon decompression in patients with intractable LSS who did not undergo PEA and those who were unresponsive to previous PEA with a balloon-less catheter.We examined 315 patients who underwent PEA and balloon decompression with balloon-inflatable catheters. Patients with intractable LSS were divided into those without previous PEA (No-PEA) and those unresponsive to previous PEA using balloon-less catheters (Prev-PEA). The numeric rating scale, Oswestry disability index, and global perceived effect of satisfaction scale were measured at 0, 1, 3, and 6 months after the intervention. Responder analysis was performed based on changes in measured scales and indices.A successful treatment response was observed at 1, 3, and 6 months after the intervention in 56.4%, 42.7%, and 32.9%, respectively, of the No-PEA group and in 48.9%, 37.8%, and 25.6%, respectively, of the Prev-PEA group. No significant between-group differences were detected. Pain intensities and functional status improved and were maintained throughout follow-up after PEA with balloon decompression using balloon-inflatable catheters.This modality may represent a useful alternative to overcome the limitations of preexisting adhesiolysis procedures.

Effectiveness and safety of acupotomy for lumbar disc herniation: a study protocol for a randomized, assessor-blinded, controlled pilot trial

BACKGROUND

Acupotomy aims to reduce pressure on the nerve, improve surrounding blood circulation, and recover the kinetic state of soft tissue in treating lumbar disc herniation. Although several previous studies have suggested the potential use and substantial benefits of acupotomy, there is still insufficient evidence regarding this technique. This trial is designed to determine if acupotomy is more effective than manual acupuncture in improving low back pain and/or leg pain, disability, lumbar mobility, and quality of life in patients with herniated lumbar disc.

METHODS

Fifty eligible patients will be randomly assigned to an acupotomy group or a manual acupuncture group in a 1:1 ratio. The experimental group will receive acupotomy at the affected side's inner core muscles and soft tissue at the level of the herniated disc where tenderness appears (twice per week for 2 weeks). The control group will receive manual acupuncture (thrice per week for 2 weeks) at GV3 (Yaoyangguan) and the bilateral BL23 (Shenshu), BL24 (Qihaishu), BL25 (Dachangshu), and BL26 (guanyuanshu) for local points and the bilateral GB30 (Huantio), BL40 (Weizhong), and BL60 (Kunlun) for distant points. The primary outcome will be the mean change in the visual analog scale from baseline to 4 weeks (2 weeks after final treatment). The Oswestry Disability Index, Modified-Modified Schober Test, and EuroQol five dimensions questionnaire will determine secondary outcomes. Adverse events will be evaluated at every visit.

DISCUSSION

This study will provide valuable data and insights for a confirmative, full-scale randomized controlled trial to determine the clinical effects of acupotomy.

Clinical Effect of Acupotomy Combined with Korean Medicine: A Case Series of a Herniated Intervertebral Disc

The aim of this study is to evaluate the effect of acupotomy for treating patients with a herniated intervertebral disc (HIVD). This case series includes five HIVD patients who were treated at the Department of Acupuncture and Moxibustion, Daejeon University Dunsan Korean Hospital, Daejeon, Korea, from January 2015 to April 2015. Acupotomy was performed three times over a 2-week period, along with Korean medical treatment. The outcomes were evaluated by using a numeric rating scale (NRS), physical examination, the Oswestry Low Back Pain Disability Index (ODI), the Short-Form 36-Item Health Survey (SF-36), and the Surgical Safety Checklist. The NRS and physical examination results, as well as the ODI scores, were improved in all cases. No significant differences were noted on the SF-36. No patients had any adverse effects. This study, with its findings of encouraging responses in reducing low back pain and radiating pain and in recovering the kinetic state of soft tissue, supports the potential use of acupotomy for the treatment of patients suffering from HIVD.

Percutaneous Adhesiolysis Versus Transforaminal Epidural Steroid Injection for the Treatment of Chronic Radicular Pain Caused by Lumbar Foraminal Spinal Stenosis: A Retrospective Comparative Study

OBJECTIVE

To investigate the efficacy of percutaneous adhesiolysis (PA) compared to fluoroscopy (FL)-guided transforaminal epidural steroid injection (TFESI) in patients with radicular pain caused by lumbar foraminal spinal stenosis (LFSS) by assessing pain relief and functional improvement at 4 and 12 weeks post-procedure.

METHODS

This retrospective study included 45 patients who underwent PA or FL-guided TFSEI for radicular pain caused by LFSS of at least 3 months' duration. Outcomes were assessed with the Oswestry Disability Index (ODI) and Verbal Numeric Pain Scale (VNS) before the procedure and at 4 and 12 weeks post-procedure. A successful outcome was defined by >50% improvement in the VNS score and >40% improvement in the ODI score.

RESULTS

ODI and VNS scores improved 4 and 12 weeks post-procedure in both groups. Statistically significant differences between groups were observed in ODI and VNS at 12 weeks (p<0.05). The proportion of patients with successful outcomes was significantly different between the two groups only at the 12-week time point.

CONCLUSION

Our study suggests that PA is effective for pain reduction and functional improvement in patients with chronic radicular pain caused by LFSS. Therefore, PA can be considered for patients with previous ineffective responses to conservative treatment. Although PA seems to be more effective than TFEFI according to the results of our study, in order to fully elucidate the difference in effectiveness, a prospective study with a larger sample size is necessary.

Effectiveness and Factors Associated with Epidural Decompression and Adhesiolysis Using a Balloon-Inflatable Catheter in Chronic Lumbar Spinal Stenosis: 1-Year Follow-Up

OBJECTIVES

This study aimed to investigate the efficacy of the combined balloon decompression with a balloon-inflatable catheter (ZiNeu) in addition to conventional epidural adhesiolysis, and to identify factors that predict patient responses.

STUDY DESIGN

An institutional single-armed prospective observational study.

SUBJECTS

Chronic refractory lumbar spinal stenosis.

METHODS

This study was performed in 61 patients with spinal stenosis who suffered from chronic (at least 3 months) lumbar radicular pain with or without lower back pain. Patients had failed to maintain improvement for more than 1 month with conventional epidural injection. The numeric rating scale (NRS) and Oswestry disability index (ODI) were each measured at 1, 3, 6, and 12 months after percutaneous epidural adhesiolysis and balloon decompression with a ZiNeu catheter.

RESULTS

The percentage of successful responders was 72.1%, 60.7%, 57.4%, and 36.1% of patients at 1, 3, 6, and 12 months, respectively. A single combined treatment of percutaneous epidural adhesiolysis and balloon decompression with a ZiNeu catheter provided sufficient pain relief and functional improvement in patients with chronic refractory lumbar spinal stenosis, and the improvement was maintained for 12 months (P < 0.001). Multivariate logistic regression analysis showed that absence of diabetes independently predicted successful response at 12 months after percutaneous epidural decompression and adhesiolysis with the balloon catheter (Odds ratio = 0.080; 95% confidence interval = 0.009-0.676; P = 0.020).

CONCLUSIONS

The combined epidural adhesiolysis and balloon decompression with a ZiNeu catheter led to significant pain relief and functional improvement in a subset of patients with refractory spinal stenosis.

Circulatory dynamics of the cauda equina in lumbar canal stenosis using dynamic contrast-enhanced magnetic resonance imaging

BACKGROUND CONTEXT

There has been no study regarding the cauda equina circulation of patients with neurogenic intermittent claudication (NIC) in lumbar spinal canal stenosis (LSCS) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

PURPOSE

The mechanism responsible for the onset of NIC was investigated using DCE-MRI to examine changes in cauda equina blood flow in patients with LSCS.

STUDY DESIGN

This was a retrospective longitudinal registry and magnetic resonance imaging study.

PATIENT SAMPLE

The subjects consisted of 23 patients who had LSCS associated with NIC (stenosis group). Ten asymptomatic volunteers who did not have NIC served as controls (control group). In the LSCS group, the cross-sectional area of the dural sac was <75 mm2 at the site of most severe stenosis. These patients were further divided into single and double stenosis subgroups.

OUTCOME MEASURES

The main measures we used were the signal intensity (S-I) ratio and the shape and size of the time intensity (T-I) curves. We compared these between the stenosis and control groups.

METHODS

At first, plain T1-weighted MR images were obtained and the lumbar dural sac cross-sectional area was measured using a digitizer. For DCE-MRI, sagittal T1-weighted images of the same slice were acquired continuously for 10 minutes after administration of gadolinium as an intravenous bolus to observe the distribution of contrast medium (gadolinium) in the cauda equina. To objectively evaluate changes in contrast enhancement of the cauda equina at the site of canal stenosis, regions of interest were established. The signal intensity (SI) ratio was calculated to compare the signal intensities before and after contrast enhancement, and time-intensity curves were prepared to investigate changes over time.

RESULTS

The static imaging findings and the changes of gadolinium uptake showed striking differences between the study and control patients. In the stenosis group, abnormal intrathecal enhancement showed around the site of stenosis on enhanced MR imaging. The SI ratio at the site of canal stenosis had a slower increase in the arterial phase when compared with that in the control group and remained high in the venous phase for up to 10 minutes. Finally, abnormal intrathecal enhancement was visible around the site of stenosis on enhanced MR imaging in all patients.

CONCLUSIONS

These clinical data indicate that cauda equina nerve roots in the LSCS patients are pathologic even when symptoms are not elicited in the supine position, suggesting that intraradicular venous congestion and edema themselves do not influence the existence of radicular symptoms.

The relationship between the duration of acute cauda equina compression and functional outcomes in a rat model

STUDY DESIGN

Immunohistochemical and behavioral study using a rat model of acute cauda equina syndrome (CES).

OBJECTIVE

To determine the effect of duration of extradural cauda equina compression (CEC) on bladder, sensory, and motor functions.

SUMMARY OF BACKGROUND DATA

Cauda equina syndrome is a devastating injury treated with surgical decompression. Controversy exists regarding the optimal timing of surgery. Animal models of CES have focused on motor recovery but have not evaluated pain behavior or bladder function.

METHODS

A 4-mm balloon-tipped Fogarty catheter was inserted between the fifth and sixth lumbar lamina into the dorsal epidural space and inflated to compress the nerve roots at the L5 level. Maximal inflation was maintained at a constant balloon pressure of 304 Kpa for 1 or 4 hours. The catheter was inserted but not inflated in sham animals. During a 4-week period, pain behavior, bladder function, and locomotor function were assessed. Postmortem bladders and the lesion site were collected for analysis.

RESULTS

Mechanical allodynia was 2-fold greater in 1-hour CEC rats than 4-hour CEC (P=0.002) and sham-operated (P=0.001) rats at 4 weeks after injury. Hind limb locomotor function was not different between groups at 4 weeks after injury. Both the 1-hour and 4-hour CEC group rats retained greater volumes of urine than the sham-operated rats throughout the 4-week period (P<0.05). At 4 weeks, bladder weight and volume were 2-fold greater in the 4-hour CEC group than in the 1-hour CEC group (P=0.006 and P=0.01, respectively). Histology of the bladder wall revealed an overall thinning after 4-hour CEC. Histology of the lesion site revealed a greater overall severity of injury after 4-hour CEC than after 1-hour CEC (P=0.04) and sham operation (P=0.002).

CONCLUSION

Our data suggest that recovery of motor function is less affected by the timing of decompression compared with bladder function and pain behavior. Early decompression preserved bladder function but was associated with allodynia.

LEVEL OF EVIDENCE

N/A.

Effects of Wonli Acupuncture Procedure in Patients with LSS: A Clinical, Retrospective Study

Background. Lumbar spinal stenosis (LSS) is a disease with increasing prevalence due to prolongation of average life span. Despite various treatment methods, many limitations remain unsolved. Objective. We are reporting cases of patients who have been treated with Wonli Acupuncture, a method of treating LSS by directly approaching the intervertebral foramen and interlaminar space with acupuncture needles different from those used in original acupuncture. Methods. A total of 82 patients with LSS were treated with Wonli Acupuncture, and out of those, 47 patients without exclusion criteria were selected for the following research. We compared the pretreatment VAS and ODI scores based on 1-year follow-up measurements. Results. The ODI value dropped by 15.3 ± 24.8 on average (from 35.2 ± 19.9 at the baseline to 19.8 ± 20.6 at the reading) (P < 0.01) and the average VAS also dropped by 19.2 ± 37.2 (from 60.7 ± 23.1 at baseline to 41.5 ± 31.9 at the reading) (P < 0.01). Conclusions. Wonli Acupuncture was found to have clinical efficacy for lumbar spinal stenosis.

Pathophysiology, diagnosis and treatment of intermittent claudication in patients with lumbar canal stenosis

Spinal nerve roots have a peculiar structure, different from the arrangements in the peripheral nerve. The nerve roots are devoid of lymphatic vessels but are immersed in the cerebrospinal fluid (CSF) within the subarachnoid space. The blood supply of nerve roots depends on the blood flow from both peripheral direction (ascending) and the spinal cord direction (descending). There is no hypovascular region in the nerve root, although there exists a so-called water-shed of the bloodstream in the radicular artery itself. Increased mechanical compression promotes the disturbance of CSF flow, circulatory disturbance starting from the venous congestion and intraradicular edema formation resulting from the breakdown of the blood-nerve barrier. Although this edema may diffuse into CSF when the subarachnoid space is preserved, the endoneurial fluid pressure may increase when the area is closed by increased compression. On the other hand, the nerve root tissue has already degenerated under the compression and the numerous macrophages releasing various chemical mediators, aggravating radicular symptoms that appear in the area of Wallerian degeneration. Prostaglandin E1 (PGE1) is a potent vasodilator as well as an inhibitor of platelet aggregation and has therefore attracted interest as a therapeutic drug for lumbar canal stenosis. However, investigations in the clinical setting have shown that PGE1 is effective in some patients but not in others, although the reason for this is unclear.

Limaprost alfadex and nonsteroidal anti-inflammatory drugs for sciatica due to lumbar spinal stenosis

PURPOSE

Limaprost, a prostaglandin E1 analog, has vasodilatory properties and increases blood flow of the nerve root. However, it has not been clarified whether limaprost affects pain sensation associated with radiculopathy due to lumbar spinal stenosis (LSS). The aim of this study was to compare the efficacy of oral limaprost with nonsteroidal anti-inflammatory drugs (NSAIDs) for radiculopathy.

METHODS

We performed a multicenter prospective randomized trial. Patients with LSS who had radicular-type neurologic intermittent claudication assessed based on a self-reported diagnostic support tool were randomized into three treatment groups. Limaprost, NSAIDs, or limaprost plus NSAIDs were administered orally for 6 weeks. Leg pain, low back pain (LBP) and the associated symptoms were assessed by a numerical rating scale (NRS) both at rest and on movement as well as the Roland-Morris Disability Questionnaire (RDQ) and Short Form (SF)-36.

RESULTS

Sixty-one patients were enrolled in the study. Each treatment finally reduced radicular pain, and the improvement was prominent in a combination treatment. There were no significant differences in radicular pain among three groups at final follow-up. LBP was not influenced by limaprost, and a significant reduction of LBP and RDQ was confirmed in a combination treatment compared with limaprost. Physical function of the SF-36 subscales after a combination treatment showed a marked alleviation compared with NSAIDs.

CONCLUSIONS

These obtained findings suggest that the effects of limaprost seem to be limited to radicular pain, not for LBP. Overall, a combination treatment might be more effective in the management of radiculopathy induced by LSS than monotherapy with either agent.

Patterns of epidural venous varicosity in lumbar stenosis

Objective

Epidural venous varicosity (congestion of the epidural vein) is rarely introduced as an influential factor of clinical symptoms. However, there are several studies suggesting that epidural venous varicosity results in neurologic symptoms. We would like to highlight evidence that epidural venous varicosity results in neurologic symptoms and the relation between epidural venous varicosity and neural structure observed during the surgery. Based on our experiences, we also propose a new classification of epidural venous varicosity.

Methods

29 patients with symptomatic lumbar stenosis received microsurgical decompression via partial hemilaminectomy. The authors retrospectively reviewed all recorded intraoperative pictures and categorized patterns of venous varicosities with relationship to neural structures.

Results

Type A is conditions in which epidural veins are dilated but located parallel to the nerve root on the lateral side of the nerve root and thus do not compress the nerve root. Type B is conditions in which varices are located on the anterior lateral side of the nerve root to compress the nerve root. Type C is conditions in which varices are encircled around the nerve root and compressing the nerve root.

Conclusion

Epidural venous varicosity is observed in most lumbar stenosis patients with clinical symptoms. Of the types, the types of epidural venous varicosity compressing nerve structures were Type B and Type C. All epidural venous varicosities were removed regardless of classification during operations. Most patients showed relief in clinical symptoms after the operation. We thought to epidural venous varicosity as a factor that causes clinical symptoms of lumbar stenosis.

Clinical experiences of transforaminal balloon decompression for patients with spinal stenosis

Lumbar spinal stenosis is a commonly treated with epidural injections of local anesthetics and corticosteroids, however, these therapies may relieve leg pain for weeks to months but do not influence functional status. Furthermore, the majority of patients report no substantial symptom change over the repeated treatment. Utilizing balloon catheters, we successfully treated with three patients who complained persistent symptoms despite repeated conventional steroid injections. Our results suggest that transforaminal decompression using a balloon catheter may have potential in the nonsurgical treatment of spinal stenosis by modifying the underlying pathophysiology.

Hemorrhagic facet cyst in the lumbar spine causing contralateral leg symptoms: a case report

Here we present a case of hemorrhagic lumbar facet cyst presenting with progressive radiculopathy only on the contralateral side. If a patient has previous back pain or neuropathy for several months and then suddenly deteriorates, hemorrhagic facet cyst of the lumbar spine should be part of the differential diagnosis. However, as in the present case, we should be aware that there is a possibility of a contralateral lesion.

A novel hypothesis about mechanisms affecting conduction velocity of central myelinated fibers

The hypothesis that gap junctions are implicated in facilitating axonal conduction has not yet been experimentally demonstrated at the electrophysiological level. We found that block of gap junctions with oleammide slows down axonal conduction velocity in the hippocampal Schaffer collaterals, a central myelinated pathway. Moreover, we explored the possibility that support by the oligodendrocyte to the axon involves energy metabolism, a hypothesis that has been recently proposed by some of us. In agreement with this hypothesis, we found that the effect of oleammide was reversed by pretreatment with creatine, a compound that is known to increase the energy charge of the tissue. Moreover, conduction velocity was also slowed down by anoxia, a treatment that obviously decreases the energy charge of the tissue, and by ouabain, a compound that blocks plasma membrane Na/K-ATPase, the main user of ATP in the brain. We hypothesize that block of gap junctions slows down conduction velocity in central myelinated pathways because oligodendrocytes synthesize ATP and transfer it to the axon through gap junctions.

Pathomechanisms of sciatica in lumbar disc herniation: effect of periradicular adhesive tissue on electrophysiological values by an intraoperative straight leg raising test

STUDY DESIGN

This study is aimed to investigate the changes of nerve root functions during the straight leg raising (SLR) test in vivo.

OBJECTIVE

To investigate the relationship between nerve root movement and the electrophysiological values during an intraoperative SLR test.

SUMMARY OF BACKGROUND DATA

The SLR test is one of the most significant signs for making a clinical diagnosis of lumbar disc herniation. A recent study showed that intraradicular blood flow apparently decreased during the SLR test in patients with disc herniation.

METHODS

The study included 32 patients who underwent microdiscectomy. During the surgery, the nerve root motion affected by the hernia was observed during the SLR test. The patients' legs were allowed to hang down to the angle at which sciatica had occurred and the change of nerve root action potentials was measured. After removal of the hernia, a similar procedure was repeated. The periradicular specimens collected during surgery were examined by light and electron microscope.

RESULTS

In all patients intraoperative microscopy revealed that the hernia was adherent to the dura mater of the nerve roots. During the SLR test, the limitation of nerve root movement occurred by periradicular adhesive tissue and amplitude of action potential showed a sharp decrease at the angle that produced sciatica. After removal of the hernia, all the patients showed smooth gliding of the nerve roots during the test, and there was no marked decrease of amplitude. Our data suggest that temporary ischemic changes in the nerve root cause transient conduction disturbances. Pathologic examination showed that the periradicular tissue consisted of the granulation with vascularization and many inflammatory cell infiltrations.

CONCLUSION

The presence of periradicular fibrosis will compound the nerve root pain by fixing the nerve in one position, thereby increasing the susceptibility of the nerve root to tension or compression.

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

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

Blood flow analysis of compressed nerve root after intravenous injection of lipo-prostaglandin E1

Prostaglandin E(1) (PGE(1)) is a potent vasodilator as well as an inhibitor of platelet aggregation and has therefore attracted interest as a therapeutic drug for lumbar canal stenosis. However, investigations in the clinical setting have shown that PGE(1) is effective in some patients but not in others, although the reason for this is unclear. The aim of the present study was to measure changes in intraradicular blood flow after intravenous injection of lipo-PGE(1) (0.15 microg/kg) using a laser Doppler flow meter in control model and nerve root compression model. Then, the nerve root in which blood flow was measured was removed and examined histologically. Intravenous injection of lipo-PGE(1) also resulted in marked increase of blood flow in the uncompressed nerve roots of the control group, but caused minimal enhancement of blood flow at the sites of nerve root compression exhibiting Wallerian degeneration. It is concluded that lipo-PGE(1) has less effect on markedly degenerated nerve roots than it does on those that are normal.