Abstract: A 48-year-old man suffered from intractable neck pain irradiating to his right arm. Magnetic resonance imaging (MRI) of the cervical spine was unremarkable. A right-sided diagnostic C6-nerve root blockade was performed. Immediately following this seemingly uneventful procedure he developed a MRI-proven fatal cervical spinal cord infarction. We describe the blood supply of the cervical spinal cord and suggest that this infarction resulted from an impaired perfusion of the major feeding anterior radicular artery of the spinal cord, after local injection of iotrolan, bupivacaine, and triamcinolon-hexacetonide around the C6-nerve root on the right side.

Abstract: STUDY DESIGN The possibility to prevent nucleus pulposus-induced functional and structural nerve root injury by selective tumor necrosis factor-alpha inhibition was assessed in an experimental model in the pig spine. OBJECTIVE The objective of the study was to evaluate the role of tumor necrosis factor-alpha in the mediation of nucleus pulposus-induced nerve injury by using selective inhibition. SUMMARY OF BACKGROUND DATA The cytokine tumor necrosis factor-alpha has been suggested to play a key role in the nerve root injury induced by local application of nucleus pulposus. However, previous studies have not been able to distinguish the effects between tumor necrosis factor-alpha and other disc-related cytokines because of the use of nonspecific cytokine inhibition. METHODS Autologous nucleus pulposus was harvested from a lumbar disc and applied to the porcine sacrococcygeal cauda equina. The pigs were simultaneously treated with two selective tumor necrosis factor-alpha inhibitors (etanercept n = 8 and infliximab n = 5), a heparin analogue (enoxaparin n = 5) or saline for control (n = 5). After 7 days the nerve conduction velocity over the application zone was determined and samples of the exposed nerve roots were collected for light microscopic evaluation. RESULTS The two tumor necrosis factor-alpha inhibitors prevented the reduction of nerve conduction velocity and also seemed to limit the nerve fiber injury, the intracapillary thrombus formation, and the intraneural edema formation. However, treatment with enoxaparin did not seem to be different from control regarding reduction of nerve conduction velocity or histologic changes. CONCLUSIONS The data clearly indicate that tumor necrosis factor-alpha is involved in the basic pathophysiologic events leading to nerve root structural and functional changes after local application of nucleus pulposus. The study therefore provides a basic scientific platform with potential clinical implications regarding the use of anti-tumor necrosis factor-alpha medication as treatment in patients with disc herniation and sciatica.

Abstract: Cranial sensory innervation is supplied mainly by the trigeminal nerves and by the first cervical nerves. Excitatory and inhibitory interactions among those nerve roots may occur in a mechanism called nociceptive convergence, leading to loss of somato-sensory spatial specificity. Three volunteers in an experimental trial had sterile water injected over their greater occipital nerve on one side of the neck. Pain intensity was evaluated 10, 30 and 120 s after the injection. Two of the patients reported intense pain. Trigeminal autonomic features, suggestive of parasympathetic activation, were seen associated with trigeminally distributed pain. These data add to and reinforce previous evidence of convergence of cervical afferents on the trigeminal sensory circuit.

Abstract: All 38 patients listed for day-case spinal endoscopy over a 12-month period (April 1998 - April 1999), who had chronic severe low back pain with a radiculopathic element, were studied prospectively. The mean [range] pain duration before treatment was 10.9 [2-26] years and 50% had failed back surgery syndrome. In all patients in whom treatment was completed (n = 34), the pain-generating nerve roots were located through symptom interaction with the patient. All had epidural scar tissue, 14 (41%) having dense adhesions. Mobilisation of adhesions around the nerve root (neuroplasty) was performed so that a pocket was formed for the subsequent placement of bupivacaine, Depomedrone and clonidine. No intra-operative complications occurred and side-effects were minimal. Follow-up over a 12-month period showed statistically significant reductions in pain scores and disability. Spinal endoscopy may be the diagnostic method of choice for epidural fibrosis. It has substantial therapeutic and research potential. Prospective randomised studies are required.

Abstract: Cytokine antagonists for use in localized clinical disorders are provided for the treatment and prevention of damage to the optic nerve, other cranial nerves, spinal cord, nerve roots, peripheral nerves or muscles caused by any one of the following: a herniated nucleus pulposus, osteoarthritis, other forms of arthritis, disorders of bone, disease, or trauma. The cytokine antagonists are used to treat these disorders by local administration. These cytokine antagonists include antagonists to tumor necrosis factor.

Abstract: STUDY DESIGN: The histochemical changes in the multifidus muscle in 29 patients with L4-L5 lumbar intervertebral disc herniation were studied. OBJECTIVES: To clarify how nerve root impairment affects the histochemical properties of the lumbar multifidus muscle in patients with lumbar intervertebral disk herniation. SUMMARY OF BACKGROUND DATA: There have been several studies on histochemical changes in lumbar muscles in patients with nerve root impairment, but the findings concerning changes in muscle fiber sizes vary among investigators. METHODS: Biopsy specimens were obtained intraoperatively from the L4 and L5 bands of the multifidus muscle on the affected and nonaffected sides. The specimens were stained with ATPase to evaluate the size of the fibers and structural changes. RESULTS: In the L5 muscle band, the mean sizes of Type 1 and Type 2 fibers on the affected side were significantly smaller than those on the nonaffected side (Type 1: P < 0.01, Type 2: P < 0.001). The decrease in size was 6.4% for Type 1 and 9.8% for Type 2. Increased percentages of Type 1 fibers and a high incidence of small angular fibers and fiber type grouping were also shown on the affected side. In contrast, in the L4 muscle band, no side-to-side differences in the histologic findings were observed. There was no significant level-to-level difference in the mean size of Type 1 or Type 2 fibers on either the affected or the nonaffected side. CONCLUSIONS: These results suggest that nerve root impairment leads to atrophy of Type 1 and Type 2 fibers, with structural changes in the multifidus muscle only at the involved level.

Abstract: STUDY DESIGN This study was designed to investigate, using neurophysiologic techniques in an in vivo rat model, the effect of application of nucleus pulposus to the nerve root on the neural activity of the dorsal root ganglion and the corresponding receptive fields. OBJECTIVES To assess a further role of the dorsal root ganglion in mechanisms of radicular pain in lumbar disc herniation. SUMMARY OF BACKGROUND DATA It has been suggested that the epidural application of autologous nucleus pulposus without mechanical compression causes nerve root inflammation and related radicular pain in lumbar disc herniation. Concerning the dorsal root ganglion, its mechanical hypersensitivity and potential for generating ectopic discharges have been reported. However, the effect of autologous nucleus pulposus on the dorsal root ganglion is uncertain. METHODS In adult Sprague-Dawley rats spontaneous neural activity was recorded from the surgically exposed L5 dorsal root using electrophysiologic techniques, and the mechanosensitivity of L5 dorsal root ganglia and corresponding receptive fields on the hind paw were measured using calibrated nylon filaments. Autologous nucleus pulposus from the tail or fat was implanted at the L5 nerve root. Neural activity was monitored for 6 hours. RESULTS Spontaneous neural activity in the nucleus pulposus group gradually increased and showed significant differences compared with the fat group from 2.5 to 6 hours after exposure. The mechanosensitivity of the dorsal root ganglia showed significant increases compared with the fat group. CONCLUSIONS After application of nucleus pulposus to the nerve root, the dorsal root ganglion demonstrated increased excitability and mechanical hypersensitivity. These results suggest that nucleus pulposus causes excitatory changes in the dorsal root ganglion.

Abstract: Trigeminal neuralgia is a well-recognized complication of multiple sclerosis, In patients with neuralgia not responding to medical treatment or transcutaneous ablative procedures, the pain can often be treated successfully by partial rhizotomy of the trigeminal sensory root. We have examined partial trigeminal rhizotomy specimens from six multiple sclerosis patients. aged between 34 and 77 years, with intractable trigeminal neuralgia lasting between 18 months and 11 years. The rhizotomy specimens were placed in buffered glutaraldehyde immediately after resection, and subsequently processed for electron microscopy. In all cases, this revealed demyelination in the proximal (CNS) part of the nerve root, with associated gliosis and variable inflammation. A consistent feature was the presence of clusters of juxtaposed axons without intervening glial processes. Similar juxtaposition of axons was previously observed in trigeminal neuralgia due to vascular compression of the nerve root. Experimental studies indicate that this arrangement of demyelinated axons is conducive to both spontaneous impulse activity and ephaptic spread of excitation. The demyelination and associated juxtaposition of axons may therefore account for key aspects of the pathogenesis of trigeminal neuralgia.

Abstract: This article reviews some recent findings on peripheral mechanisms related to the development of oro-facial pain after trigeminal nerve injury. Chronic injury-induced oro-facial pain is not in itself a life-threatening condition, but patients suffering from this disorder undoubtedly have a reduced quality of life. The vast majority of the work on pain mechanisms has been carried out in spinal nerve systems. Those studies have provided great insight into mechanisms of neuropathic spinal pain, and much of the data from them is obviously relevant to studies of trigeminal pain. However, it is now clear that the pathophysiology of the trigeminal nerve (a cranial nerve) is in many ways different to that found in spinal nerves. Whereas some of the changes seen in animal models of trigeminal nerve injury mimic those occurring after spinal nerve injury (e.g., the development of spontaneous activity from the damaged axons), others are different, such as the time-course of the spontaneous activity, some of the neuropeptide changes in the trigeminal ganglion, and the lack of sprouting of sympathetic terminals in the ganglion. Recent findings provide new insights that help our understanding of the etiology of chronic injury-induced oro-facial pain. Future investigations will hopefully explain how data gained from these studies relate to clinical pain experience in man and should enable the rapid development of new therapeutic regimes.

Abstract: Diagnostic nerve blocks: The popularity of neural blockade as a diagnostic tool in painful conditions, especially in the spine, is due to features like the unspecific character of spinal pain, the irrelevance of radiological findings and the purely subjective character of pain. It is said that apart from specific causes of pain and clear radicular involvement with obvious neurological deficits and corresponding findings of a prolapsed disc in MRI or CT pictures, a diagnosis of the anatomical cause of the pain can only be established if invasive tests are used [5]. These include zygapophyseal joint blocks, sacroiliacal joint blocks, disc stimulation and nerve root blocks. Under controlled conditions, it has been shown that among patients with chronic nonradicular low back pain, some 10-15% have zygapophyseal joint pain [58], some 15-20% have sacroiliacal joint pain [36, 59] and 40% have pain from internal disc disruption [60]. The diagnostic use of neural blockade rests on three premises. First, pathology causing pain is located in an exact peripheral location, and impulses from this site travel via a unique and consistent neural root. Second, injection of local aneasthetic totally abolishes sensory function of intended nerves and does not affect other nerves. Third, relief of pain after local anaesthetic block is attributable solely to block of the target afferent neural pathway. The validity of these assumptions is limited by complexities of anatomy, physiology, and psychology of pain perception and the effect of local anaesthetics on impulse conduction [28]. Facet joints: The prevalence of zygapophyseal joint pain among patients with low back pain seems to be between 15% and 40% [62], but apparently only 7% of patients have pure facet pain [8, 29]. Facet blockade is achieved either by injection of local anaesthetic into the joint space or around the medial branches of the posterior medial rami of the spinal nerves that innervate the joint. There are several problems with intraarticular facet injections, mainly failure to enter the joint capsule and rupture of the capsule during the injection [11]. There is no physiological means to test the adaequacy of medial nerve block, because the lower branches have no cutaneous innervation. Medial ramus blocks (for one joint two nerves have to be infiltrated) are as effective as intraarticular joint blocks [37]. Reproducibility of the test is not high, the specifity is only 65% [61]. For diagnosis of facet pain fluoroscopic control is always necessary as in the other diagnostic blocks. Sacroiliacal joint: Definitely the sacroiliacal joint can be the source of low back pain. Stimulation of the joint by injection in subjects without pain produces pain in the buttock, in the posterior thigh and the knee. There are many clinical tests which confirm the diagnosis, but the interrater reliability is moderate [53]. Intraarticular injection can be achieved in the lower part of the joint with fluoroscopic guidance only, but an accurate intraarticular injection, which is confirmed by contrast medium, even at this place is often difficult. It is not clear whether intraarticular spread is necessary to achieve efficacy. Discography: Two primary syndromes concerning the ventral compartment have been described: anular fissures of the disc and instability of the motion segment. In the syndrome of anular tear, leakage of nucleus pulposus material into the anulus fibrosus is considered to be the source of pain. The studies of Vaharanta [71] and Moneta [41] show a clear and significant correlation between disc pain and grade 3 fissures of the anulus fibrosus. intervertebral discs are difficult to anaesthetize. Intradiskal injections of local anaesthetics may succeed in relieving the patient's pain, but such injections are liable to yield false negative results if the injected agent fails to adequately infiltrate the nerve endings in the outer anulus fibrosus that mediate the patient's pain. In the majority of cases MRI provide adaequate information, but discography may be superior in early stages of anular tear and in clarifying the relation between imaging data and pain [71]. Selective spinal nerve injection: In patients with complicated radiculopathy, the contribution of root inflammation to pain may not be certain, or the level of pathology may be unclear. Diagnostic root blocks are indicated in the following situations: atypical topography of radicular pain, disc prolapses or central spinal stenosis at more than one level and monoradicular pain, lateral spinal stenosis, postnucleotomysyndrome. Injection of individual spinal nerves by paravertebral approach has to be used to elucidate the mechanism and source of pain in this unclear situations. The premise is that needle contact will identify the nerve that produces the patient's characteristic pain and that local anaesthetic delivered to the pathogenic nerve will be uniquely analgesic. Often, this method is used for surgical planning, such as determining the site of foraminotomy. All diagnostic nerve root blocks have to be done under fluoroscopic guidance. Pain relief with blockade of a spinal nerve cannot distinguish between pathology of the proximal nerve in the intervertebral foramen or pain transmitted from distal sites by that nerve. Besides, the tissue injury in the nerve's distribution and neuropathic pain (for instance as a result of root injury) likewise would be relieved by a proximal block of the nerve. Satisfactory needle placement could not be achieved in 10% of patient's at L4, 15% at L5 and 30% at S1 [28]. The positive predictive value of indicated radiculopathy confirmed by surgery ranged between 87-100% [14, 22]. The negative predictive value is poorly studied, because few patients in the negative test group had surgery. Negative predictive values were 27% and 38% of the small number of patients operated on despite a negative test. Only one prospective study was published, which showed a positive predictive value of 95% and an untested negative predictive value [66]. Some studies repeatedly demonstrated that pain relief by nerve root block does not predict success by neuroablative procedures, neither by dorsal rhyzotomy nor by dorsal gangliectomy [46]. Therapeutic nerve blocks - facet joints: Intraarticular injection of steroids offer no greater benefit than injections of normal saline [8, 15] and long lasting success is lacking. In this case, a denervation of the medial branches can be considered. To date three randomized controlled studies of radiofrequency facet denervation have been published. One study [20] reported only modest outcomes and its results remained inconclusive, another study [72] with a double blind controlled design showed some effects in a small selected group of patients (adjusted odds ratio 4.8) 3, 6 and 12 months after treatment, concerning not only reduction of pain but alleviating functional disability also. The third study (34a) showed no effect 3 months after treatment. Discogenic pain: Intradiscal radiofrequency lesions, intradiscal injections of steroids and phenol have been advocated, but there are no well controlled studies. Just recently, intradiscal lesion and denervation of the anulus has been described with promising results, but a randomized controlled study is lacking up to now [31, 55]. Epidural Steroids: Steroids relieve pain by reducing inflammation and by blocking transmission of nociceptive C-fiber input. Koes et al. [33] reviewed the randomized trials of epidural steroids: To date, 15 trials have been performed to evaluate the efficacy, 11 of which showed method scores of 50 points (from 100) ore more. The trials showed inconsistent results of epidural injections. Of the 15 trials, 8 reported positive results and 7 others reported negative results. Consequently the efficacy of epidural steroid injections has not yet been established. The benefits of epidural steroid injections seem to be of short duration only. Future efficacy studies, which are clearly needed, should take into account the apparent methological shortcomings. Furthermore, it is unclear which patients benefit from these injections. In our hands the injection technique can be much improved by fluoroscopic guidance of the needle, with a prone position of the patient, and lateral injection at the relevant level and with a small volume (1-2 ml) and low dose of corticosteroid (20 mg triamcinolone in the case of a monoradicular pain, for example). In the case of epidural adhesions in postoperative radicular pain [50], the study of Heafner showed that the additional effect of hyaloronidase and hypertonic saline to steroids was minimal. In our hands there was no effect in chronic radicular pain 3 months after the injection.

Abstract: Study Design. A cross-sectional study in sciatic population.Objectives.To evaluate the separate roles of nerve root entrapment—based on magnetic resonance imaging—and other discogenic pain mechanisms on disability and physical signs among symptomatic sciatic patients.Summary of Background Data. Data

Abstract: Rhombencephalitis due to Listeria monocytogenes is characterized by progressive cranial nerve palsies and subacute inflammation in the brain stem. In this paper, we report observations made on mice infected with L. monocytogenes. Unilateral inoculation of bacteria into facial muscle, or peripheral parts of a cranial nerve, induced clinical and histological signs of mainly ipsilateral rhombencephalitis. Similarly, unilateral inoculation of bacteria into lower leg muscle or peripheral parts of sciatic nerve was followed by lumbar myelitis. In these animals, intraaxonal bacteria were seen in the sciatic nerve and its corresponding nerve roots ipsilateral to the bacterial application site. Development of myelitis was prevented by transsection of the sciatic nerve proximally to the hindleg inoculation site. Altogether, our results support the hypothesis that Listeria rhombencephalitis is caused by intraaxonal bacterial spread from peripheral sites to the central nervous system.

Abstract: STUDY DESIGN A lumbar radiculopathy model investigated pain behavioral responses after nerve root reinjury. OBJECTIVES To gain a further understanding of central sensitization and neuroinflammation associated with chronic lumbar radiculopathy after repeated nerve root injury. SUMMARY OF BACKGROUND DATA The pathophysiologic mechanisms associated with chronic radicular pain remain obscure. It has been hypothesized that lumbar root injury produces neuroimmunologic and neurochemical changes, sensitizing the spinal cord and causing pain responses to manifest with greater intensity and longer duration after reinjury. However, this remains untested experimentally. METHODS Male Holtzman rats were divided into two groups: a sham group having only nerve root exposure, and a chromic group in which the nerve root was ligated loosely with chromic gut suture. Animals underwent a second procedure at 42 days. The chromic group was further divided into a reinjury group and a chromic-sham group, in which the lumbar roots were only re-exposed. Bilateral mechanical allodynia was continuously assessed throughout the study. Qualitative assessment of spinal cord glial activation and IL-beta expression was performed. RESULTS Mechanical allodynia was significantly greater on both the ipsilateral and contralateral sides after reinjury (P < 0.001), and the response did not return to baseline after reinjury, as it did with the initial injury. There were also persistent spinal astrocytic and microglial activation and interleukin-1beta expression. CONCLUSIONS The bilateral responses support central modulation of radicular pain after nerve root injury. An exaggerated and more prolonged response bilaterally after reinjury suggests central sensitization after initial injury. Neuroinflammatory activation in the spinal cord further supports the hypothesis that central neuroinflammation plays an important role in chronic radicular pain.

Abstract: Although several clinical applications of transpedicular screw fixation in the lumbar spine have been documented for many years, few anatomic studies concerning the lumbar pedicle and adjacent neural structures have been published. The lumbar pedicle and its relationships to adjacent neural structures were in- vestigated through an anatomic study. Our objective is to highlight important considerations in perform- ing transpedicular screw fixation in the lumbar spine. Twenty cadavers were used for observation of the lumbar pedicle and its relations. After removal of whole posterior bony elements including spinous processes, laminae, lateral masses, and inferior and superior facets, the isthmus of the pedicle was exposed. Pedicle width and height (PW and PH), interpedicular distance (IPD), pedicle-inferior nerve root distance (PIRD), pedicle-superior nerve root distance (PSRD), pedicle-dural sac distance (PDSD), root exit angle (REA), and nerve root diameter (NRD) were measured. The results indicated that the average distance from the lumbar pedicle to the adja- cent nerve roots superiorly, inferiorly and to the dural sac medially at all levels ranged from 2.9 to 6.2 mm, 0.8 to 2.8 mm, and 0.9 to 2.1 mm, respectively. The mean PH and PW at L1-L5 ranged from 10.4 to 18.2 mm and 5.9 to 23.8 mm, respec- tively. The IPD gradually increased from L1 to L5. The mean REA in- creased consistently from 35° to 39°. The NRD was between 3.3 and 3.9 mm. Levels of significance were shown for the P<0.05 and P<0.01 levels. On the basis of this study, we can say that improper placement of the pedicle screw medially and infe- riorly should be avoided.

Abstract: This study evaluates the use of magnetic resonance imaging (MRI) in the diagnosis of lumbosacral nerve root anomalies. Prevalence of anomalous nerve roots has been based on anatomic dissection or preoperative neuroradiologic investigations. Three hundred seventy-six patients with low back pain and/or radicular pain who underwent MRI of the lumbar spine were reviewed. Sixty-five cases of nerve root anomalies were found (an incidence of 17.3%) of which 1 case of cranial origin, 5 cases of caudal origin, 2 cases of conjoined nerve root, and 57 cases of furcal nerve roots (15.1%) were identified. Furcal nerve roots were most commonly found at L3 and L4 levels and were classified, according to their division, into intra-and extraforaminal. MRI provided accurate information on lumbosacral nerve root anomalies.

Abstract: Study design An experimental study to clarify the effects of pentoxifylline, as an anti-tumor necrosis factor-alpha therapy on endoneurial fluid pressure in the dorsal root ganglion using an animal model of herniated nucleus pulposus. Objectives To investigate the effects of anti-tumor necrosis factor-alpha therapy to nucleus pulposus-induced nerve root/dorsal root ganglion changes. Summary of background data It has been reported experimentally that application of nucleus pulposus into epidural space induces morphologic and functional changes in the nerve roots and induces compartment syndrome in the dorsal root ganglia. Tumor necrosis factor-alpha has been considered a key pathogenic factor in the initiation and maintenance of neuropathic pain states. Methods A total of 11 adult, female Sprague-Dawley rats had their left L5 nerve roots and associated dorsal root ganglions exposed. Autologous nucleus pulposus was applied to the L5 nerve root just proximal to the dorsal root ganglion. A piece of Spongel (Yamanouchi Pharmaceutical Co., Tokyo) containing 20 microL of 1000 microg/mL pentoxifylline was applied with the nucleus pulposus (NP+PTX group). In control animals nucleus pulposus was applied with a piece of Spongel containing 20 microL of physiologic saline solution in a similar fashion (NP+PS group). Endoneurial fluid pressure was recorded with a servo-null micropipette system using glass micropipettes with tip diameters of 4 microm. Endoneurial fluid pressure in the dorsal root ganglion was measured before and 3 hours after application of test substances. After measurement of endoneurial fluid pressure, the nerve root and dorsal root ganglion were processed for histology and evaluated by light microscope. Results Values of endoneurial fluid pressure before application of test substances were as follows: 2.4 +/- 1.2 cm H2O in the NP+PS (control) group and 1.8 +/- 0.4 cm H2O in the NP+PTX group. There was no statistically significant difference between these two pretreatment measurements. However, values of endoneurial fluid pressure after application were as follows: 8.6 +/- 1.8 cm H2O in the NP+PS group and 2.9 +/- 0.8 cm H2O in the NP+PTX group. Values of endoneurial fluid pressure in the NP+PTX group were significantly lower compared with the NP+PS group. Histologic examination consistently showed only a slight degree of edema evident in the NP+PTX group compared with the NP+PS group. Conclusion Pentoxifylline, an anti-tumor necrosis factor-alpha drug, prevented the dorsal root ganglion compartment syndrome caused by topical application of nucleus pulposus. Anti-inflammatory cytokine therapy may become an effective treatment of sciatica due to disc herniation.

Abstract: STUDY DESIGN A case report of a patient with cervical spinal cord and nerve root compression caused by a meningioma en plaque together with calcification of the posterior longitudinal ligament is presented,with a review of the literature. OBJECTIVE To present the diagnosis of a calcified dural meningioma en plaque, with extradural extension into the ligamentum flavum, in a woman with cervical myelopathy and neuropathy. SUMMARY OF BACKGROUND DATA This case demonstrates that the cervical spine can be involved in dural meningioma en plaque with calcifications, in a manner mimicking ossification of the ligamentum flavum, which has never been previously reported. METHODS A patient presenting with cervical cord and nerve root compression caused by ossification of the posterior longitudinal ligament and a concurrent calcified dural meningioma en plaque was treated surgically and has made a gradual recovery. Imaging studies,surgical findings, and histopathologic evaluation were analyzed to support the diagnosis. RESULTS At surgery, ossification of the posterior longitudinal ligament was noted, along with a calcified lesion involving the posterior cervical dura and the adjacent ligamentum flavum. A calcified meningioma was diagnosed by histopathologic examination of the dural-based lesion. CONCLUSION Although previously not described, the diagnosis of calcified dural meningioma en plaque should be considered in all patients presenting with spinal cord and/or nerve root compression,even at cervical levels. Although ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum are more common etiologies of partially circumferential spinal calcification, dural-based meningiomas with extension into the surrounding ligaments demand early recognition because they can be associated with a poorer prognosis.

Abstract: Background and Objective The Holmium: YAG (Ho: YAG) laser has been used for the ablation of prolapsed discs but alternative techniques are available, and this application remains controversial. It also has potential for the decompression of nerve roots within narrowed foraminae with the technique of endoscopic laser foraminoplasty. Traditional methods of decompression necessitate a major surgical procedure with potential destabilisation of the lumbar spinal segment. Nevertheless, minimally invasive techniques are attractive only if serious complications can be avoided. This study reports the peak temperatures reached in surrounding tissues with and without saline irrigation. Study Design/Materials and Methods Investigation of the hypothesis was carried out in excised sheep lumbar spines. T-type thermocouples were used for the measurement of tissue temperatures during laser ablation of nerve root foraminae. The temperature was assessed in the nerve root, dura mater, and disc space. Results The Ho: YAG laser was effective in widening the foraminae by approximately 1.5 mm with a total energy of 4.60 kJ. This was statistically significant in both vertical and horizontal directions (P < 0.0003 and P < 0.00005, respectively). The mean temperature of the nerve root, dura, and disc space during the procedure was 44 ± 3.1°C, 42.8 ± 4.7°C, and 41 ± 3.4°C respectively. There were transient high peaks seen in the temperature profiles. Using saline irrigation at 27 ml/minutes these temperatures were reduced to 34.1 ± 1.8°C (P = 0.0002), 34.9 ± 1.5°C (P = 0.002), and 37.2 ± 1.2°C (P < 0.014), for nerve roots, dura, and disc space respectively. Conclusions Laser ablation of bone and ligament for nerve root decompression using the Ho: YAG laser may offer substantial advantages, but the risk of serious complication may only be avoided if the technique is combined with saline irrigation. Lasers Surg. Med. 29:33–37, 2001. © 2001 Wiley-Liss, Inc.

Abstract: Interstitial cystitis is the most disabling nonmalignant disorder seen by urologists. Chronic debilitating urinary bladder symptoms (severe pain and pelvic floor muscular dysfunction) often progress despite maximal medical attempts at management. Although the exact cause remains unknown, a neuropathic etiology has recently been suggested( 1,2). This case report describes the use of Selective Nerve Root Stimulation (SNRS) for the treatment of intractable pelvic pain and motor dysfunction in a patient with Interstitial cystitis (IC).

Abstract: Study design Morphologic features of the dorsal root ganglia were investigated in patients with herniation of the nucleus pulposus by means of magnetic resonance myelography. Objectives This study was undertaken to assess morphologic changes of the dorsal root ganglia in patients with herniation of the nucleus pulposus and to determine the relations between the morphologic features of the dorsal root ganglia and clinical features. Summary of background data It has recently been reported that application of the nucleus pulposus to a nerve root induces edema in the rat dorsal root ganglion. Edema in the human dorsal root ganglion resulting from lumbar disc herniation has not been discussed in the literature, to the authors' knowledge. Methods Eighty-three consecutive patients (average age 42.1 years; range 17 to 77 years) with monoradicular symptoms were examined. Dorsal root ganglion morphologic features, i.e., indentations and swelling, were evaluated by magnetic resonance myelography. The dorsal root ganglion swelling at each level was quantitatively expressed as a ratio of the dorsal root ganglion width on the involved side to that of the contralateral side and was termed dorsal root ganglion ratio. Eighty-three uninvolved levels were chosen as controls in a randomized manner. Factors possibly contributing to the morphologic changes in the dorsal root ganglion were investigated. Neurologic symptoms, evaluated by the Japan Orthopaedic Association scoring system, were correlated to the morphologic changes. The morphologic features were followed up for 1 year after treatment in a small group of patients. Results Dorsal root ganglion indentations were always found in the narrowed intervertebral foramens. The incidence of indentations was significantly higher at the involved nerve roots (10.8%) than at the uninvolved nerve roots (4.0%) (P = 0.026). Patients with dorsal root ganglion indentations were significantly older (P = 0.0008). Leg pain scores in patients with indentations were significantly poor (P = 0.007). The dorsal root ganglion ratios were significantly higher at the involved levels than at the uninvolved levels (P = 0.001); the means +/- SD were 1.19 +/- 0.25 and 1.08 +/- 0.13, respectively. Patients with lateral herniated nucleus pulposus had significantly higher dorsal root ganglion ratios than those with central herniated nucleus pulposus (P = 0.0001); the mean ratios +/- SD were 1.48 +/- 0.32 and 1.10 +/- 0.12, respectively. A moderate positive correlation was found between dorsal root ganglion ratio and age (Pearson's correlation coefficient = 0.313). There was moderate negative correlation between the dorsal root ganglion ratio and leg pain, gait, motor, and total Japan Orthopaedic Association score (correlation coefficients were = -0.385, -0.350, -0.422, and -0.358, respectively). The dorsal root ganglion ratios were significantly diminished at 1-year follow-up (P = 0.001); the means +/- SD were 1.22 +/- 0.22 and 1.09 +/- 0.07, respectively. Indentations observed before treatment disappeared after treatment. Conclusions Swelling and impingement in the involved dorsal root ganglion were clearly visualized by magnetic resonance myelography. The swelling and indentations were well correlated with severity of leg pain. These findings have important value in understanding the pathophysiology of the nerve roots in herniated nucleus pulposus.

Abstract: Study Design The relations between the location of the dorsal root ganglion and pre-and postoperative symptoms were reviewed retrospectively in 27 patients who underwent radiculography and posterior discetomy Objectives To evaluate the clinical features and surgical outcome of extraforaminal lumbar disc herniation based on the location of dorsal root ganglion Summary of Backgroun Data The location of dorsal root ganglia has been reported to be coorelated with a variety of radicular symptoms Extraforaminal lumbar disc herniation has several specific clinical features, one of which is sever radicular pain However, there is no report in the litterature on the association between the location of the dorsal root ganglia and the severity of the symptoms of extraforaminal lumbar disc herniation Methods The radiographic location of the dorsal root ganglion of each compressed nerve root was determined by preoperative direct radiculograms All patients were classified into the following three groups according to the location of dorsal root gaanglion: intraspinal, intraforaminal, and extraforaminal The incidences of these dorsal root ganglion and clinical paramethers such as the level of the compressed nerve root, the degree of limitation on straight leg raising test, the severity of the pre- and postoperative subjective symptoms (leg pain, low back pain, and walking capacity), clinical signs (sensory and motor disturbance), and the recovery rate were investigated Results The degree of limitation on the staight leg raising test in the extraforaminal group tended to be low, compared with that in the intraspinal and intraforaminal groups Low back pain in the extraforaminal groups Low back pain in the extraforaminal groups was more sever than that in the intraspinal and intraforaminal groups Preoperative leg pain in the extraforaminal groups was significantly more sever that that in the intraspinal group, and the walking capacity in the extraforaminal groupe tended to be loxer than that in the intraspinal and intraforaminal groups No significant differances were found between the location of dorsal root ganglion and the preoperative sensory or motor disturbance and surgical outcomes Conclusion The location of the dorsal root ganglion might influence the severity of radicular symptoms (pain and walking distance) in patients with extraforaminal lumbar disc herniation

Abstract: The authors present the case of a 62-year-old man with a 4-month history of progressive left-sided C-5 radiculopathy and dizziness. Neuroimaging studies revealed a looped vertebral artery (VA) that had migrated into the widened left C4-5 intervertebral foramen. The patient underwent vascular reconstruction of the VA loop, in which there was minimal manipulation of the C-5 nerve root, via a left-sided anterolateral approach after a balloon occlusion test. Postoperatively the patient's symptoms improved immediately, and there were no signs of recurrence within the 2-year follow-up period. This excellent outcome supports the belief that a proper surgical reconstruction of the compressive, tortuous VA should be the therapeutic option of choice, which carries a lower risk of the nerve root injury and improves the hemodynamics in the posterior circulation.

Abstract: STUDY DESIGN A case report of a man with a gigantic cellular schwannoma in the sacrum treated with high sacral amputation accompanied by careful nerve root-sparing dissection. OBJECTIVES To describe the atypical clinical course of an intrasacral cellular schwannoma and the surgical procedure of high sacral amputation performed in a way to prevent needless sacrifice of functionally essential nerve roots. SUMMARY OF BACKGROUND DATA Fundamentally, a cellular schwannoma is a benign tumor, but the clinical course is atypical. The symptoms are mild and the clinicopathologic features often mislead us to make a diagnosis of malignancy. The occurrence rate of intraosseous cellular schwannoma was reported to be 0.2% of all bony tumors, and the main location was the retroperitoneal space in the pelvis. Forty-one cases of giant intrasacral schwannomas have been reported so far. Among them, large sacral schwannoma with anterior cortex erosion and associated intrapelvic extension was extremely rare. METHODS The patient presented with a 5-year history of right leg and buttock pain, which did not disturb his daily activities. After a histopathologic diagnosis and a complete set of image studies, high sacral amputation with preservation of uninvolved nerve roots was performed at S1-S2 through a combined anterior and posterior approach. Both S1 nerve roots and the right S2-S3 nerve roots were saved using a threaded saw. The lumbar spine was stabilized to the pelvic girdle using spinal instrumentation with posterolateral fusion. RESULTS Eighteen months after the tumor was resected the patient had a very good clinical outcome, and there were no radiologic signs of instability or recurrence of the tumor. Locomotor function of both lower extremities and bowel and urinary functions were well maintained. The patient returned to his previous work. CONCLUSIONS High sacral amputation following a combined anteroposterior approach provided good results without causing any disability. A detailed preoperative planning and careful dissection of uninvolved nerve roots prevented unnecessary neurologic impairment in locomotion and the detrusor and anorectal function.

Abstract: Neurosarcoidosis is a diagnostic challenge, especially if systemic symptoms are absent. We present a 49-year-old woman with isolated neurosarcoidosis. The main symptom was loss of vision in the left eye. Brain MR imaging showed 6 high-signal white matter lesions frontotemporally on proton density and T2-weighted turbo spin-echo images. Coronal fat-saturated turbo FLAIR images of the orbits showed a swollen left optic nerve with increased signal intensity, which finding has not been previously published in sarcoid optic neuropathy. A control MR examination showed meningeal enhancement of the left optic nerve and leptomeningeal enhancing lesions around the brain stem. Spinal MR revealed leptomeningeal enhancement throughout the spinal cord and asymptomatic enhancing cauda equina lesions, mimicking subarachnoid tumour seeding, and an enhancing nerve root mass at Th12/L1. Biopsy of the latter lesion revealed non-caseating granulomas consistent with sarcoidosis.

Abstract: STUDY DESIGN An experimental study was conducted to evaluate the effects of lidocaine on nucleus pulposus-induced pathophysiologic changes. OBJECTIVES To investigate the effects of lidocaine on blood flow in the hind paws and endoneurial fluid pressure in the dorsal root ganglia in a rat model of herniated nucleus pulposus, and to clarify the therapeutic mechanisms of nerve root infiltration. SUMMARY OF BACKGROUND DATA It has been shown experimentally that application of nucleus pulposus to the nerve roots increases endoneurial fluid pressure and decreases blood flow in the dorsal root ganglia and the corresponding hind paw. These changes are thought to be an important pathogenic mechanism associated with sciatica caused by disc herniation. Nerve root infiltration is one of the nonoperative effective therapies for radiculopathy caused by disc herniation. However, the therapeutic mechanisms still are unknown. METHODS For this study, 21 Sprague-Dawley rats were used. Autologous nucleus pulposus was applied to the nerve root with a piece of Spongel containing lidocaine (lido group) or physiologic saline solution (control group). In Series 1 of this study (Blood Flow in the Hind Paw), blood flow in the corresponding hind paws was monitored continuously using a laser Doppler flowmeter before application of the test solutions, and every 5 minutes thereafter for an additional 3 hours in both the control (n = 5) and lido (n = 5) groups. In Series 2 of this study (Endoneurial Fluid Pressure in the Dorsal Root Ganglion), endoneurial fluid pressure was recorded with a servo-null micropipette system using glass micropipettes before and 3 hours after application of the test solutions in both the control (n = 6) and lido (n = 5) groups. After measurements, dorsal root ganglia were assessed for histology. RESULTS In Series 1, blood flow in the corresponding hind paw in the control group showed significant reduction as compared with that of the Lido group, starting about 90 minutes after application (P < 0.01-0.05). Hind paw blood flow in the lido group did not show any reduction during measurements. In Series 2, the value of endoneurial fluid pressure in the lido group 3 hours after application was significantly lower than in the control group (P < 0.01). Interstitial (endoneurial) edema in the dorsal root ganglion in the lido group appeared to be qualitatively less than in the control group. CONCLUSIONS The data indicate that lidocaine reduces the pathophysiologic changes in the dorsal root ganglion and hind paws induced by nucleus pulposus. These effects of lidocaine may relate to the mechanisms underlying the therapeutic effects of nerve root infiltration.