Primary Rami Research Articles

Progressive Myelopathy in a 32-Year-Old Man

<h3>History</h3> A 32-year-old man presented with bilateral progressive paresthesia and numbness over a two-year period following a motor vehicle accident. He reported the recent onset of urinary incontinence. On examination, decrease in pain and sensation to touch and pinprick in both lower extremities, more marked on the left side, was elicited. The findings of electromyographic studies were consistent with involvement of the posterior primary rami at the T10-11 level. Lateral roentgenograms of the thoracic spine showed a triangular bony density projecting into the spinal canal (open arrow) at the site of T10-11 (Fig 1). Low-dose metrizamide myelography with computed tomography (CT) was accomplished. The CT scans will be demonstrated subsequently. An operative procedure was performed. <h3>Diagnosis</h3> Ossification of the ligamentum flavum at T10 through T12 causing myelopathy. A CT scan using low doses of metrizamide shows ossification of the ligamentum flavum (LF) (open arrows), compressing the spinal cord at T10-11

Acupuncture points of the lumbar plexus.

This communication is the fifth in a series of six publications describing acupuncture points by anatomic nomenclature. This article describes acupuncture points in the lumbar region of the posterior body wall, the inguinal and pelvic regions of the lower abdomen, and the medial surface of the thigh and leg. Acupuncture points in these regions are generally established by anatomic features of the lumbar spinal nerves. Nerve branches of the posterior primary rami of the lumbar spinal nerves and the lumbar plexus provide the anatomic basis for acupuncture points in these regions and are used to name the points accordingly.

The development and postnatal organization of primary afferent projections to the rat thoracic spinal cord.

Primary afferent projections to the thoracic spinal cord in fetal and postnatal rats were labelled by applying horseradish peroxidase (HRP) to the central stumps of cut peripheral nerves. Diaminobenzidine (DAB) and tetramethyl benzidine (TMB) histochemical processing procedures were used to reveal the HRP reaction product. In postnatal rats, individual muscle nerves were labelled to reveal the organization of muscle afferent projections to the motor nuclei. The terminals of muscle afferents were distributed widely across the dendritic arbors of motoneurons supplying the same muscles. No spatial segregation of the terminations of different populations of muscle afferents was discernable. Afferents supplying different regions of the skin were labelled by applying HRP to the dorsal and ventral primary rami of the spinal nerves. Afferents in the dorsal rami projected to lateral portions of both the ipsilateral and contralateral dorsal horns while afferents in the ventral rami projected to the medial portions of both dorsal horns. The projections of the dorsal rami were shifted caudally relative to those of the ventral rami. This relationship reflects the fact that the regions of skin innervated by the dorsal rami are displaced caudally relative to those innervated by the corresponding ventral rami. In fetuses, dorsal rami were labelled alone or in combination with ventral rami. These experiments disclosed the time course of development of the projections to different laminae of the spinal gray matter and revealed that afferents in the two primary rami project to appropriate regions in the ipsilateral and contralateral dorsal horns from the very outset.

The development and postnatal organization of motor nuclei in the rat thoracic spinal cord.

The topographic organization of the motor nuclei supplying individual thoracic muscles in postnatal rats was investigated by horseradish peroxidase (HRP) labelling from the periphery. To determine whether aspects of the same organization are apparent at early developmental stages, we used HRP to label neurons contributing axons to the two primary rami of thoracic nerves in rat fetuses ranging in age from the 13th day of gestation to birth. This developmental period includes stages during which peripheral nerves and muscles are forming. The results show that motoneurons in the appropriate positions in the ventral horn have axons in each primary ramus even at stages prior to the innervation of muscle. However, in fetuses at certain developmental stages, there are also neurons located outside the motor nuclei which send axons into the peripheral nerves.

Radiofrequency Facet Denervation: A Treatment Alternative in Refractory Low Back Pain with or without Leg Pain

Summary In summary, there exists a definite clinical syndrome marked by worsening subjective complaints associated with increased activity, especially those activities that unduly stress the lumbar articulations and their soft tissue investitures. The complaint of low back pain is frequently associated with pain of a referred nature into one or both legs, usually limited to an area above the knee. Unusual areas of pain perception have been described as emanating from noxious stimuli to the periarticular nerves, which are branches of the posterior primary ramus. Objective findings are scarce, with the x-ray studies of myelography and CT scanning being normal. These patients are refractory to time-honored conservative methods of treatment such as bracing, bed rest, analgesics, and physical therapy. A treatment alternative exists that employs, as its basis of approach, known anatomic facts. It relies on the fact that certain miniscule nerves and their branches bear a constant and reproducible location with respect to bony landmarks of the spine. By virtue of this anatomy, these nerves are readily accessible to percutaneous destruction. The procedure of radiofrequency denervation is safe, and in my experience, it has yet to cause permanent worsening of a patient's clinical condition, a claim that cannot often be made for spine fusion or laminectomy. The procedure of radiofrequency denervation has been shown to be effective in satisfactorily reducing pain perception in greater than 70 per cent of patients, provided that those patients were screened first with preoperative facet blocks. For a patient to be considered a candidate for the procedure, pain relief from the blocks must be substantial and reproducible. Consideration of the procedure as a denervation of the motion segment must be disposed of. At best, I have come to think of it as a desensitizing procedure, a concept for which I am indebted to Dr. Vert Mooney. I seek to reduce the sensory input from the only nociceptive site accessible to percutaneous destruction. There still remain the innervations to the neural contents of the spinal canal, the annulus fibrosis, and the posterior longitudinal ligament made via the sinuvertebral nerve with this being multisegmental in its innervation.23 It is possible that this nociceptive input is responsible for the tendency toward partial relief of symptoms and a seemingly time dependent deterioration of relief following facet denervation procedures. No alteration is being made in the stability of the motion segments, so as such, the pathologic process continues, labeled by many as “mechanical instability.” All that I have attempted to do is to modify the host response to the noxious stimulation from one area of the spine. As degeneration of the motion segment continues, made possible by vocational stress, body habitus, or decreased muscle conditioning, further segmental instability ensues. The part played by the sinovertebral nerve may then become more important, thus explaining these late failures. The procedure of radiofrequency facet denervation should be applied only in a well thought out treatment program and should never act as a substitute for the time honored treatment modality of rest, immobilization, analgesia, weight reduction, graduated exercise, and spinal education.

Electromyographic Findings in Patients with Low Back Pain Due to Unsuspected Primary and Metastatic Spinal or Paraspinal Muscle Disease

Electromyographic studies were performed on 16 patients with intractable low back pain and no antecedent history of malignancy or metastatic disease. In each case, electromyographic evidence of severe segmental denervation limited to the paraspinal muscles innervated by the posterior primary rami was found. Subsequent diagnostic studies in each patient revealed a primary neoplasm or tumor metastasis as the source of pain. Applying current knowledge of neuromuscular physiology, the electromyograph may prove to be a valuable aid to the early detection of remote metastasis to the spine and paraspinal muscle structures.

Interruption of pain pathways in the treatment of the cervical syndrome.

In the cervical syndrome a distinction should be made between an upper and a lower type. The upper type is usually emanating from the intervertebral or facetal joints, since pathology causing nerve-root irritation is confined to the more caudal segments. In the lower type nerve-root irritation is usually the cause of pain but secondary irritation of the facetal joints can be an important contributing factor. Treatment should primarily be conservative. If this fails and if surgical intervention is not indicated an attempt should be made to interrupt pain pathways. This can be done by division of the posterior primary rami or by making a radio-frequency lesion in the dorsal root ganglion. The results indicate these procedures can be of considerable help in a group of patients who do not respond to any other treatment.

The treatment of chronic back pain

Structures innervated by the dorsal primary ramus play a significant part in the genesis of chronic backache and associated leg pain. The features of this syndrome are described and compared with those in the more familiar clinical picture following intervertebral disc degeneration. However these clinical entities are seldom entirely separate and the diagnosis is often also complicated by psychosomatic factors and the consequences of previous back surgery. A technique of percutaneous facet denervation with a radiofrequency probe, although by no means successful in every case, is entirely safe and a very wothwhile procedure. It has helped many patients, who would otherwise have been disabled by pain and restricted in their activities.

Localized Pruritus-Notalgia Paresthetica

Notalgia paresthetica, possibly an isolated sensory neuropathy involving the posterior primary rami of thoracic nerves T2 through T6, and appearing as pruritus of the back, is apt to be encountered by both dermatologists and neurologists. Two cases illustrate this disorder.

The Role of Laminectomy, Facet Rhizotomy, and Epidural Steroids

A retrospective review of the treatment of chronic back and extremity pain is presented. Laminectomy is most effective for pain secondary to direct compression of the neural elements. Treatment of pseudoradicular pain requires identification of the source of pain input. Facet rhizotomy is specific for pain arising from the posterior primary rami. Pain input from the recurrent sinuvertebral nerve requires epidural injection.

Quantitative study on the fetal cervical dorsal root ganglion and observations on its relationship with the spinal nerve complex in the albino mouse.

In mouse fetuses aged 12, 14, 16, 18 and 20 days, the cervical dorsal root ganglion was studied quantitatively. The main growth in volume of the interneuroblastic spaces was between the 12th and 16th day of pre-natal life while the main increase in volume of its neuroblasts occurred in the subsequent 4 days. Thus, it was postulated that the growth and branching of the neuroblastic dendrites, growth of the neuroglial elements and the vascular ramifications inside the ganglion occurred mainly between the 12th and 16th day of pre-natal life. Different modalities in the spatial relationship between the dorsal root ganglion and the different components of the spinal nerve were met with. At times, the trunk of the spinal nerve was located inside the ganglion. At that site, the posterior primary ramus emerged from it and appeared as a branch of the ganglion. The ventral root sometimes passed close to the fibrous capsule of the ganglion. In other cases, it passed inside the ganglion, dividing the ganglionic neuroblasts into dorsal and ventral groups. These either remained ensheathed by one fibrous capsule or became divided into two separate masses that remained connected to each other by the fibrous dural sheath.

The Incidence of Denervation of the Sacrospinales Muscles Following Spinal Surgery

The posterior paravertebral muscles of the lumbar spine are supplied segmentally by the posterior primary rami of the lumbar and sacral nerves. Electromyographic examination of these muscles is used to seek evidence of specific lumbar and sacral nerve root compromise. An anatomic study of the posterior rami and their branches has demonstrated that these nerves are very liable to be damaged during a routine posterior surgical approach to the lumbar spine. In a clinical and electromyographic study of 113 patients, all of whom underwent posterior lumbar spinal surgery, it was shown that some measure of denervation of the paravertebral muscles occurred in 96% of cases. Denervation was shown to persist for many years following surgery, and reservation was only partial. It was concluded that diagnostic electromyography of the paraspinal muscles in a postsurgical patient is of no value.

Percutaneous radiofrequency lumbar rhizolysis (rhizotomy).

Low-back pain may arise from degenerative changes in the posterior joints of the lumbar spine. These joints are innervated by a branch of the posterior primary ramus, which follows an antomically constant course. Pain impulses from these joints can be interrupted by coagulating the nerve with a radiofrequency wave, the probe having been placed in the area of the nerve percutaneously. Percutaneous lumbar rhizolysis was carried out under local anesthesia on an outpatient basis in 82 patients, most of whom had multiple level rhizolysis, Rhizolysis was successful in 67% of patients with mechanical low-back pain without evidence of disc herniation and nerve-root compression or psychogenic pain, who had not previously undergone an operation for relief of the pain.

The organization of neuronal somata in the first sacral spinal ganglion of the cat

Abstract The basis of organization of neuronal somata within a spinal ganglion has been studied using histological techniques. The positions of the largest neuronal cell bodies, which are thought to innervate muscle receptors, were plotted for unoperated and sham operated animals. These ganglion cells were found in all sectors of the ganglion and their distribution generally reflected that of the total ganglion cell population in the respective sectors. The positions of neuronal somata undergoing the axonal reaction following various nerve lesions were plotted. Altered neurons were not preferentially accumulated in any sector of the ganglion after lesions of cutaneous nerves, nerves to muscle, or nerves innervating the distal part of the hind limb, but they often occurred in clusters which were found in all parts of the ganglion. Following a lesion of either the pudendal nerve, the S1 dorsal primary ramus, or the S1 ventral root, altered neurons tended to be grouped in one or more sectors of the ganglion. These data suggest that ganglion cells innervating skin or muscle often occur in small groups distributed throughout the ganglion, while processes of afferent neurons which branch from the spinal nerve and do not travel through a limb plexus tend to have their cell bodies restricted to a particular region of the ganglion.

The anatomy of backache.

Backache is a common condition. Dissections have been made of human cadavers with the aid of a microscope. The posterior primary rami of segmental nerves have been examined. Particular reference is made to the distribution of medial divisions of the nerves. The innervation of the posterior vertebral joints and the posterior aspect of the sacrum is illustrated.

RHIZOLYSIS: A PHYSIOTHERAPIST'S REPORT

In the Australian medical and paramedical fields considerable interest has been stirred by percutaneous rhizolysis, the procedure introduced here by Dr. W. E. Skyrme Rees, M.B., Ch.B., F.R.C.S. The technique itself comes under intensive scrutiny. In theory the technique is a "percutaneous bilateral section of the posterior primary rami", either lumbar or cervical.

On the rami intermedii of the spinal nerves and their equivalent offshoots. A contribution to classification of the trunk muscles.

Distribution patterns of the nerves of supply to the intertransversarii posteriores cervicis, levatores costarum breves and intertransversarii laterales lumborum were carefully studied in nine body-halves of male human cadavers. Any of these muscles lie wegded in between the commencements of the dorsal and ventral primary rami of the spinal nerves. In the great majority of the cases the levatores costarum breves derived their nerve supply in the upper segments from both primary rami of the corresponding spinal nerves and in the lowest segments as the rami intermedii from the bifurcation of each spinal nerve into its primary rami. Both patterns of the nerve supply to the levatores costarum breves were turned into one another in the intervening segments. The intertransversarii posteriores cervicis of similar location to the levatores costarum breves in the thoracic region were regarded as the upper serial homologues of these muscles, because they were supplied by both primary rami of the spinal nerves, similarly the intertransversarii laterales lumborum, principally supplied by the rami intermedii of the spinal nerves, as the lower serial homologues of the same muscles.

SUBCUTANEOUS LUMBAR “RHIZOLYSIS”— AN ASSESSMENT OF 200 CASES

Two hundred cases of intervertebral disc syndrome have been subjected to the Rees “rhizolysis” and the results of the operation in certain cases, even of long duration of pain, would suggest that the procedure should be added to the armamentarium of those dealing with back problems. The actual reason for pain relief is thought to be due to section of the posterior primary ramus.

Neuralgic amyotrophy: a clinical and electromyographic study.

The clinical syndrome of neuralgic amyotrophy is strikingly stereotyped. It consists of severe burning pain of sudden onset fn the outer aspect of the arm accompanied by wasting and weakness of the muscles of the upper limb. Affected muscles may be completely paralysed. The pain is occasionally transient, but usually lasts up to six weeks, and sometimes even longer. Weakness or paralysis follows its onset in the space of one to four days in 80% of cases. The motor symptoms are usually maximal at the outset, but progression over a period of seven days may be observed. The site of the pain and the muscles affected are not necessarily correlated. Paralysed muscles are flaccid and waste rapidly, but fasciculation is not obtrusive. Sensory changes occur most commonly when the circumflex nerve is affected. In the majority of patients sys temic disturbances?for example, malaise, fever?are minimal (Turner, 1944 ; Parsonage and Turner, 1948). Muscles affected are usually serratus anterior (Richardson, 1942), spinati, deltoid, and trapezius (Spillane, 1943), but any muscle of the arm may be deranged and bilateral involvement is quite common. Wyburn-Mason (1941) encountered 42 cases in a period of nine months, chiefly during the summer. Spillane (1943) described 46 cases in Service men, 26 of whom developed the disorder while they were in hospital for some other reason. Other authors have noticed a close association with hospital (Parsonage and Turner, 1948)* and French workers have often considered injections of serum?with brisk serum reactions?to be responsible (Pollet, 1924). This is not by any means an invariable experience (Richardson, 1942). Both sexes are affected ; in the earlier papers males preponderate in the ratio of 12:1, but Turner and Parsonage (1957) included nearly as many women as men. Age ranges of 30-79 (Wyburn Mason, 1941) and 16-54 years (Turner, 1944) have been quoted. Prognosis has been said to be poor where there is much muscle-wasting (Spillane, 1943 ; Turner, 1944), but Dixon and Dick (1945) described recovery taking up to two years in 13 out of 16 patients who had been severely affected. Turner and Parsonage (1957) agreed that return of power was the rule, the time needed for recovery varying with the nerves affected. Recurrent attacks have been described (Dixon and Dick, 1945). The site of the lesion responsible for the disorder has been variously suggested as the anterior primary rami of lower cervical and upper thoracic roots (Wyburn-Mason, 1941), with trunks of peripheral nerves affected in addition to or in isolation from the roots (Turner, 1944) and sometimes the spinal cord itself (Parsonage and Turner, 1948). No specific evidence for these conclusions has been offered. Necropsy evidence is lacking. The cause of the neuronal damage has been thought to be an inflammatory reaction of infectious or allergic origin. Electromyography may give some information regarding the site if not the aetiology of the lesion, and a group of patients with neuralgic amyotrophy have been examined in this way.

Further observations on the cutaneous branches of the dorsal primary rami of the spinal nerves.

AbstractRecent investigators suggest that dermatomes extend as consecutive bands from the dorsal median line and question the existence of dorsal axial lines. Our observations were made on serial sections of human embryos and fetuses prepared with neurofibrillar stains.Cervical nerves 1, 6, 7 and 8 failed to have cutaneous branches in most cases, the remainder usually had cutaneous branches.With a few exceptions in T 1, all thoracic dorsal rami had cutaneous branches. Usually T 1, 2 and 3 became cutaneous through medial branches, while T 9 through 12 did so through lateral branches. However T 4 through 8 constitute a transition zone where many of these nerves became cutaneous through both medial and lateral branches. Thoracic 4, 5 and 6 tended to have cutaneous distribution through medial branches, but T 7 and 8 through lateral branches.All lumbar dorsal rami having cutaneous distribution did so through lateral branches, but independent branches became progressively less frequent below L 1. Lumbar 4 lacked direct cutaneous branches in most cases and succeeding nerves in all cases. These nerves form the dorsal sacral plexus.The deficit in cutaneous distribution of lower lumbar rami was not as pronounced as in the lower cervical region. A deficit is significant in relation to dorsal axial lines.