Abstract: Forty-six cases of anomalous lumbosacral nerve roots were found in a series of 2123 patients who underwent myelography with water-soluble contrast medium. The anomalies were classified into five types. In Types I and II, one or more nerve roots emerged from the theca at a more cranial (Type I) or caudal (Type II) level than normal. In Type III, two or more roots emerged through closely adjacent openings in the dura, whereas in Type IV two nerve roots emerged from the dural sac combined as one nerve trunk. In Type V, two roots were connected by an anastomotic branch shortly after their emergence from the dura. The anomalies were usually unilateral and the fifth lumbar and first sacral-nerve roots were the most frequently involved. Type-III and Type-IV anomalies were the most common (69 per cent). Twenty-one per cent of the patients had lumbosacral anomalies and one had congenital absence of the articular facets of the lumbosacral joint on the side of the nerve-root anomaly. In seven patients the anomalous root or roots were compressed by a herniated disc, and the roots were entrapped in a lateral recess or intervertebral foramen in two. Symptoms and signs of nerve-root compression were usually severe, even in the patients with a small disc protrusion. The severity of the clinical findings appeared to be due to the reduced mobility of the anomalous roots. Adequate surgical decompression led to satisfactory final results in all nine patients.

Abstract: The lumbo-sacral ligament (LSL) was studied in 42 specimens. It extends from the L5 vertebra to the ala of the sacrum and forms, with the structures to which it is attached, an osteofibrotic tunnel as an extension of the intervertebral foramen. The 5th lumbar nerve root passes through the tunnel over the ala of the sacrum and behind the LSL. A branch of the 4th lumbar nerve root passes in front of the LSL to join the 5th below the ligament to form the lumbo-sacral trunk. The sympathetic ramus communicans to the L5 root always penetrates the LSL at its superior border and reaches the nerve inside the tunnel. Branches of the ilio-lumbar vessels accompany the L5 root. Large osteophytes on the inferior border of L5 and tightness of the LSL were often found to cause entrapment and compression of the L5 nerve root against the ala of the sacrum.

Abstract: Ketamine, a cataleptic analgesic substance which theoretically may block pain receptors in the spinal cord, providing pain relief without respiratory depression, was injected intrathecally with or without benzethonium chloride 0.1 mg/ml (a preservative) into 8 monkeys under anaesthesia. Two monkeys received saline (control group). No assessment as to relief from experimental pain was possible. All Monkeys recovered normally from anaesthesia and were found moving about in their enclosures without gross evidence of neurological impairment. No adverse reactions were noted. Ten days after the subarachnoid injection the monkeys are sacrificed. Autopsy was performed within 30 minutes. No macroscopic abnormality of the cord was noticed. Microscopic examination revealed oedema of a few nerve roots in all animals, irrespective of whether ketamine or saline was injected intrathecally. Focal degeneration with loss of myelin and axoplasm was observed within a solitary nerve root in 2 monkeys that had received ketamine, 1 with and 1 without preservative. However, in these animals lumbar puncture proved difficult and bloody taps ensued. Hence trauma could have been a contributing factor in these 2 cases. None of the other monkeys showed these changes, regardless of group.

Abstract: Administration of beta,beta'-iminodipropionitrile (IDPN) to rodents has previously been shown to produce neurofilament-filled axonal swellings in the proximal regions of motor and sensory nerve fibers. Because of the distinctive distribution of these swellings, IDPN has been classed as a proximal axonopathy and thereby distinguished from other disorders in which similar axonal swellings occur in the distal parts of the axon (distal axonopathies). This report describes the pathology in the peripheral nerves of cats which received intermittent injections of IDPN and calls attention to two previously undescribed pathological changes. First, in addition to the typical proximal swellings associated with IDPN, these animals developed numerous axonal swellings within the distal branches of the sciatic nerve. Distal swellings were present as early as 23 days after initiation of intoxication, indicating that they formed locally (rather than developing in the proximal axon and undergoing transport into the distal regions). The second finding was Wallerian-like degeneration within the affected nerve branches. These changes in the distal sciatic nerve and its branches closely resembled the pathology of the distal axonopathies produced by agents such as the neurotoxic hexacarbons and carbon disulfide. The pathological similarities suggest that IDPN may share with these agents pathogenetic mechanisms to an extent not previously suspected.

Abstract: The operative results of 63 cases of lumbar disc disease with surgically confirmed conjoined nerve roots are reviewed. The first 55 patients were treated by standard hemilaminectomy and discectomy, with only 30% reporting a good result. Of the last eight patients treated by hemilaminectomy, pediculectomy, and discectomy, seven patients returned to work. Te rationale for and the technique of pediculectomy are discussed in detail. Clinical, radiological, and surgical clues indicating the presence of the conjoined nerve root anomaly are reviewed.

Abstract: With the intention of estimating the extent and site of damage in brachial plexus injuries which involve close to the root outlet and also the distal portion, cortical somatosensory evoked potentials (SEP) were recorded in 21 patients by directly stimulating the exposed brachial plexus. In 38 avulsed nerve roots which showed positive sensory action potentials (SNAP)/nerve action potentials (NAP) in their peripheral part, 15 roots (nine patients) were apparently in continuity and confirmed as root avulsion injury by the absence of cortical SEP. However, 11 roots (ten patients) which showed neither SNAP nor SEP would suggest either extensive lesions involving root and more distal segment or a combination of root avulsion and postganglionic injury. Fourteen patients who showed a positive Tinel's sign had at least one root with a postganglionic type lesion, but cortical SEP evoked by stimulation of the most proximal root zone sometimes revealed a reduced amplitude and prolonged latency. This would indicate the retrograde extension of damage. To confirm the extent and degree of the nerve lesions in brachial plexus injuries, an intraoperative SEP and NAP recording is very useful, practical, and also indispensable.

Abstract: Cervical or lumbar nerve root infiltration is a valuable and reliable technique when the localization of the symptomatic level cannot be assessed by any other diagnostic procedure. In order to obtain the morphological basis for this technique, anatomical and experimental studies were carried out with 6 mongrel dogs and 7 human cadavers. In the spinal canal a membranous structure, the epidural membrane, interposing between the dura and yellow ligament can be found. There is a fibrous covering around the nerve root in the intervertebral foramen, which is called the epiradicular sheath. The epiradicular sheath is formed by a lateral extension of the superficial layer of the posterior longitudinal ligament blended with the epidural membrane enveloping the dura. When epidurography is performed on dog cadavers both at the cervical and lumbar levels, the contrast material is located between the dura and epidural membrane. When cervical nerve root infiltration is performed on dog and human cadavers, the contrast material spreads under the epiradicular sheath. Based on these anatomical and experimental studies it can be concluded that selective infiltration of each nerve root with the contrast material and/or local anesthetic is possible by the existence of the epiradicular sheath. And the epiradicular sheath is responsible for the fact that the contrast material is located around the nerve roots in a tubular fashion.

Abstract: The CT appearance of conjoined nerve roots in 5 patients is described, together with the similarity to a herniated nucleus pulposus and differentiation between the two using the ''blink mode.'' Patients should not have pain secondary to this anatomical variant, which may help distinguish it from a herniated disk clinically unless they occur at the same level.

Abstract: Five cases of spinal leptomeningeal infiltration by systemic cancer are presented and myelographic features are discussed with a review of the literature. Common characteristic features are parallel longitudinal striations due to thickened nerve roots in the cauda equina and bizarre irregular filling defects with varying degrees of blocks, resembling arachnoiditis. Another pattern described in the literature consists of multiple nodular filling defects along the nerve roots of the cauda equina.

Abstract: Nine patients with redundant lumbar nerve root syndrome were identified using positive-contrast myelography, seven with metrizamide and two with iophendylate. Serpiginous intradural filling defects occurred in conjunction with a complete or partial extradural block and spinal stenosis. These redundant nerve roots were seen on the cephalic side of the block. Eight of the nine patients had pseudoclaudication. One case was found incidentally during a cervical myelogram. This series is presented to demonstrate the characteristic myelographic pattern that should be recognized and differentiated from tortuous intradural blood vessels. Possible causes are discussed.

Abstract: ~/ To define the site, degree, and dynamics of mechanical compression of the spinal nerve roots, pressure was measured in 42 patients with clinical symptoms and myelographic findings indicating central lumbar spinal stenosis. Pathological pressure on the cauda equina was found in 67% of the patients. The pressure in the region of the spinal block was high during standing and walking, and in several patients exceeded mean arterial blood pressure. The block pressure was the main mechanical factor in the central part of the spinal canal causing pain and paresis. Elevated fluid pressure caudal to the block was an additional but usually subordinate factor. In 33% of the patients, normal pressure on the cauda equina was found, and lateral compression of multiple nerve roots seemed to be the only mechanical symptom-causing factor. Clinically, these patients could not be distinguished from patients with central compression. After laminectomy with decompression of the cauda equina, the field should be inspected for lateral narrowing which, if present, should be treated.

Abstract: Five cases of spinal leptomeningeal infiltration by systemic cancer are presented and myelographic features are discussed with a review of the literature. Common characteristic features are parallel longitudinal striations due to thickened nerve roots in the cauda equina and bizarre irregular filling defects with varying degrees of blocks, resembling arachnoiditis. Another pattern described in the literature consists of multiple nodular filling defects along the nerve roots of the cause equina.

Abstract: Deformities of the margins of the contrast material-filled lumbar thecal sac are common findings at myelography in patients with low back pain, but not all such deformities are due to herniated disks. Differentiation at Amipaque myelography between a diffusely bulging disk (unlikely to cause nerve root compression) and a herniated disk (which typically causes nerve root compression) is based on the curvature and extent of the extradural deformity of the anterolateral margin of the contrast-filled sac and on the presence of fusiform widening of the most distal part of the affected nerve root. The deformity caused by a bulging disk is rounded, usually symmetrical (although occasionally more prominent on one side), and does not extend above or below the disk space; the nerve root is uniform in caliber and normal in size. The deformity caused by a herniated disk is angular and extends cephalad and/or caudal to the level of the disk space; the affected nerve root is usually widened in its most distal visible part. A consecutive series of 33 patients with clinically suspected lumbar disk herniation and no previous history of back surgery underwent laminectomy. Using the criteria listed above for differentiation of bulging from herniated disk on Amipaque myelography, the myelographic diagnosis was correct in all six operatively confirmed bulging disks and in 26 (96%) of 27 operatively verified disk herniations.

Abstract: By a fluorescence-microscopic technique, the distribution of the antineoplastic glycoside adriamycin (doxorubicin) was studied in the peripheral nervous system (PNS) of normal adult mice after i.v. injection. Doses comparable to those used in patients for treatment of malignant diseases were used. The orange-red fluorescence of the drug was observed in dorsal root ganglia, in the trigeminal ganglia, and in the superior cervical sympathetic ganglia where it was preferentially accumulated in the nuclei of satellite cells. This nuclear labeling was a very quick process which occurred in the superior cervical ganglion within 15 s after the injection. Adriamycin-fluorescent nuclei were also observed in the suprarenal medulla. Fluorescent nuclei were present within the pre- and postganglionic sympathetic nerve trunks close to the superior cervical ganglion but not in the endoneurium of the trigeminal and the sciatic nerves or in the spinal nerve roots. In such structures labeled cells appeared in the connective tissue sheaths covering the nerves and the roots. No adriamycin-induced fluorescence was detected in the myenteric plexus of the intestine. Our study thus shows that i.v. injected adriamycin is distributed preferentially within areas of the PNS where the blood vessels are known to be highly permeable.

Abstract: ✓ Long-term electrophysiological cross-talk between nerve fibers has been demonstrated in rat sciatic nerve following induction of an amputation neuroma. Experiments were designed to establish an anatomical basis for this phenomenon. The sciatic nerve was transected and the epineurium oversewn with 10-0 nylon in 16 adult male Sprague-Dawley rats. The resulting neuromas were prepared for ultrastructural analysis 7, 14, 30, and 60 days later. An analysis of the unmyelinated nerve fibers showed normal configurations of the fibers, with normal organelles, separated by Schwann cell processes in the neuroma. However, degenerating unmyelinated nerve fibers and nerve fibers with masses of neurofilaments were often observed. In approximately 10% of the total population observed, there were two or more unmyelinated nerve fibers in a single Schwann process fascicle. Some of the multiple unmyelinated nerve fiber fascicles had nerve fibers that were in membranous apposition. This configuration of unmyelinated axons co...

Abstract: Five patients with subacute myelo-optico-neuropathy (SMON) were studied by short-latency somatosensory evoked potentials (SEPs) in response to electrical stimulation of the median nerve and the posterior tibial nerve. SEPs with median nerve stimulation were normal in all cases, but SEPs with posterior tibial nerve stimulation were abnormal in two patients with severe sensory loss in the legs. Abnormalities suggested normal peripheral conduction but a marked attenuation of the cortical component and delayed central conduction. These findings were in conformity with postmortem morphometric analysis, which showed marked reduction of myelinated fibers in the gracile fascicle but only slight reduction of large myelinated fibers in the sural nerve. The pathophysiology of SMON appears to be mainly a central distal axonopathy.

Abstract: Deformities of the lateral margins of the contrast material-filled lumbar thecal sac are common findings at myelography in patients with low back pain, but not all such deformities are due to herniated disks. Differentiation at Amipaque myelography between a diffusely bulging disk (unlikely to cause nerve root compression) and a herniated disk (which typically causes nerve root compression) is based on the curvature and extent of the extradural deformity of the anterolateral margin of the contrast-filled sac and on the presence of fusiform widening of the most distal part of the affected nerve root. The deformity caused by a bulging disk is rounded, usually symmetrical (although occasionally more prominent on one side), and does not extend above or below the disk space; the nerve root is uniform in caliber and normal in size. The deformity caused by a herniated disk is angular and extends cephalad and/or caudal to the level of the disk space; the affected nerve root is usually widened in its most distal visible part. A consecutive series of 33 patients with clinically suspected lumbar disk herniation and no previous history of back surgery underwent laminectomy. Using the criteria listed above for differentiation of bulging from herniated disk on Amipaque myelography, the myelographic diagnosis was correct in all six operatively confirmed bulging disks and in 26 (96%) of 27 operatively verified disk herniations.

Abstract: The spinal nerve root origins of the cutaneous nerves arising from the brachial plexus were investigated in 10 babiturate-anesthetized dogs by stimulating dorsal roots C5 to T2 and recording from each cutaneous nerve Upon completion of the experiment, the contributions of the spinal nerve ventral branches to the brachial plexus were verified by anatomic dissection The brachial plexus was formed by the ventral branches of C6 to T2 in 8 dogs, C6 to T1 in 1 dog, and C5 to T1 in 1 dog The cutaneous branch of brachiocephalicus nerve was formed primarily by contributions from the C6 dorsal root The cranial lateral cutaneous brachial nerve, a branch of the axillary nerve, was formed predominantly from C6 to C7 The median nerve received contributions primarily from C7, C8, and T1, and the communicating branch from the musculocutaneous to the median nerve contained fibers primarily from C7 and C8 The medial and lateral branches of the superficial branch of the radial nerve arose from C6, C7, C8, and T1, with the medial branch generally arising 1 segment craniad to the lateral The palmar and dorsal branches of the ulnar nerve arose predominately from C8 and T1, and the caudal cutaneous antebrachial nerve of the ulnar arose predominately from T1 and T2

Abstract: 1. In order to investigate the characteristics of synapses formed by a foreign nerve in skeletal muscle of the frog, the hypoglossal nerve in Rana pipiens was implanted under the cutaneus pectoris (c.p.) muscle which was denervated 1 month later. 2. Within 1 week of crushing the c.p. nerve, hypoglossal nerve fibres could be seen extending towards the denervated end-plates and the muscle contracted in response to stimulation of the implanted nerve. 3. The synapses formed by the foreign nerve differed from those of the original nerve in several ways. The mean quantal content (m) of end-plate potentials (e.p.p.s) evoked by stimulation of the hypoglossal nerve in c.p. was lower than that of e.p.p.s evoked by stimulation of the regenerated original nerve. The mean latency between stimulation of the implanted nerve and the onset of e.p.p.s was longer than that for stimulation of the original nerve. Stimulation of the foreign nerve often evoked multiphasic e.p.p.s whereas these were only seen on original nerve stimulation during the first 3 months after regeneration. These abnormalities of the foreign innervation persisted for at least 6 months after crushing the original nerve. 4. The geniohyoid muscle (which is normally innervated by the hypoglossal nerve) and c.p. appear to contain similar types of muscle fibre. Furthermore, when the geniohyoid muscle became reinnervated by the hypoglossal nerve after it had been crushed, the synapses formed were more effective than those formed by the hypoglossal nerve in c.p. 5. Even if reinnervation of c.p. by its nerve was delayed by cutting the brachial nerve at its exit from the vertebral column, the synapses formed by the hypoglossal nerve in c.p. remained abnormal, suggesting that an incompatability exists between the c.p. muscle and the hypoglossal nerve. 6. In spite of the differences found between the synapses formed by the hypoglossal nerve and the original nerve in c.p., there was no evidence of regression of the hypoglossal innervation during the period of observation.

Abstract: Three cases of painless root compression following disc extrusion are reported. Each patient showed the typical course of disease with the neurological deficit appearing at the same time as the sciatic pain disappeared. At operation the nucleus pulposus was found in the spinal canal. It is suggested that disappearance of the pain is related to the perforation of the anulus fibrosus and posterior longitudinal ligament by the nucleus pulposus. The operative findings justified early operation in these patients, and prompt surgery is recommended for similar cases.

Abstract: Twenty-two patients presented during the last 3 years with unilateral symptoms and signs of a lumbar monoradiculopathy indistinguishable from those of a disc herniation. All had compression of the nerve root posteriorly by a hypertrophic facet without anterior compression from the disc. None of the patients had spinal claudication. Preoperative evaluation with computed tomographic (CT) scanning was disappointing as the pathology was correctly defined in only 1 of 10 patients. Lumbar myelography was helpful, but did not always localize the lesion. The decision to operate was based primarily on the clinical grounds of persistent or progressive radiculopathy. The operative techniques used were two-level hemilaminectomy in 7 patients, single level laminectomy in 4, and multilevel laminectomy in 11. Surgical exploration revealed that the site of compression ranged from the medial canal to the lateral recess. The root was compressed by inferior facets 8 times and by superior facets 14 times. Back pain was relieved in 12 of 15 patients, and leg pain was relieved in 19 of 21. Neurological deficit was relieved in 19 and improved in 3. It is concluded that standard CT and myelographic techniques may not anatomically define the point of radicular compression. Intraoperatively the root must be explored from its dural origin to a point beyond the pedicle to ensure adequate decompression. Most, but not all patients with hypertrophic radicular compression will improve after surgical decompression.

Abstract: Within the spinal cord meninges of SJL/J mice afflicted with chronic relapsing experimental allergic encephalomyelitis for up to seven months postinoculation, networks of aberrant regenerated nerve fibres myelinated by Schwann cells have been observed. These P.N.S. elements are believed to have been derived from incoming sensory fibres from the spinal nerve roots which had been interrupted during acute stages of the disease. This phenomenon might also have been related to the occurrence of marked nerve fibre loss and gliosis within superficial tracts in the spinal cord. P.N.S. elements within the subarachnoid space were first apparent six weeks postinoculation, and were distributed around the entire spinal cord and tended to be more concentrated around meningeal blood vessels. Schwann cells associated with these fibres frequently contained centrioles and cilia and daughter Schwann cells apparently arose from parent cells already committed to axons.

Abstract: The action of Co2+ on the isolated frog spinal cord was studied by extracellular application of the ion in the superfusing solution. A complete and reversible blockade of chemical synaptic transmission by Co2+ (3 mmol/l) could be achieved after a superfusion period of 20-30 min. During continued Co2+ application (greater than 60 min) the following effects upon the motoneuron membrane, dorsal root and ventral root fibres were observed. Motoneurons and ventral root fibers: 1. prolongation of initial segment action potential to a maximum of 30 ms, 2. blockade of the long afterhyperpolarization, 3. abolition of adaptation, 4. increased duration of fibre action potential in the ventral root, 5. backfiring after ventral root stimulation. Dorsal root fibres: 1. prolongation of the extraspinal fibre action potential, 2. marked prolongation of the action potential of the terminal region, 3. backfiring of multiple action potentials after dorsal root stimulation. Even in the presence of Co2+, when synaptic transmission was completely blocked, strong convulsive reactions of the isolated spinal cord were observed. Intracellular injection of Co2+ into motoneurons did not affect the action potential, but led to a shift of the EIPSP towards the membrane potential. The results indicate that the induction of convulsive reactions by Co2+ is mainly due to a prolongation of action potentials. The plateau-like deformation of the action potential of the initial segment membrane and presumably of the terminal region of nerve endings results in retrograde propagation of action potentials and in some cases induces oscillatory discharge of single neurons.

Abstract: After injury to the intracranial portion of the facial nerve, undegenerated myelinated nerve fibres were seen to form a distinct bundle in the peripheral part of the transverse fascicular area at the level distal to the geniculate ganglion The numbers and diameters of the fibres were similar to those seen in the nervous inter-medius portion of the facial nerve in experimental animals The average number of these apparently non-motor fibres was 2500 Their average diameter was 24 mum

Abstract: ✓ The authors report an unusual case of intradural schwannoma, without demonstrable nerve root connection. An original explanation is given.