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Biomedical subjects

N Bogduk

Publications and source records attributed to N Bogduk.

At least 73 records · Page 4Linked to original sources
PubMed1995

The utility of comparative local anesthetic blocks versus placebo-controlled blocks for the diagnosis of cervical zygapophysial joint pain.

BACKGROUND: The development of target-specific local anesthetic blocks has enabled pain physicians to explore the anatomical source of chronic spinal pain. However, such blocks rely on subjective responses and may be subject to the placebo effect. Comparative local anesthetic blocks have been advocated as a means of identifying true-positive cases and excluding placebo responders. This paradigm employs two local anesthetics with different durations of action; only patients who obtain reproducible relief and correctly identify the longer-acting agent are considered positive. OBJECTIVE: Our objective was to evaluate the reliability of comparative blocks of the medial branches of the cervical dorsal rami in the diagnosis of cervical zygapophysial joint pain. DESIGN: We compared comparative blocks and the criterion-standard of randomized, double-blind, placebo-controlled blocks. SETTING: The study was conducted at a tertiary referral center. PATIENTS: We studied the first 50 consecutive patients referred for assessment of chronic neck pain (> 3 months' duration) after a motor vehicle accident, who completed a series of placebo-controlled blocks after an initial positive response. Patients were 41 +/- 11 years (mean +/- SD) old with a male/female ratio of 1:2. METHODS: Patients underwent three blocks using three different agents-lignocaine, bupivacaine, and normal saline--administered on separate occasions, in random order and under double-blind conditions. The diagnostic decision based on comparative blocks alone was compared with that based on placebo-controlled blocks. RESULTS: Comparative blocks were found to have a specificity of 88%, but only marginal sensitivity (54%). Although comparative blocks result in few false-positive diagnoses, their liability is that they result in a high proportion of false-negative diagnoses. Expanding the comparative blocks diagnostic criteria to include all patients with reproducible relief, irrespective of duration, increases sensitivity to 100% but lowers specificity to 65%. CONCLUSIONS: Whether physicians use comparative or placebo-controlled blocks depends upon the implications of their results. If innocuous therapy will be prescribed, comparative blocks might suffice. However, when diagnostic certainty is critical, such as in a medicolegal context or when surgical intervention is contemplated, placebo-controlled blocks are recommended.

Adult↗
PubMed1995

Prevalence and clinical features of lumbar zygapophysial joint pain: a study in an Australian population with chronic low back pain.

OBJECTIVES: To determine the prevalence of pain arising from the zygapophysial joint in patients with chronic low back pain and to determine whether any clinical features could distinguish patients with and without such pain. METHODS: Sixty three patients with chronic low back pain were studied prospectively. All patients underwent a detailed history and physical examination as well as a series of intra-articular zygapophysial joint injections of 0.5% bupivacaine starting at the symptomatic level to a maximum of three levels or until the pain was abolished. They also received injections of normal saline into paraspinal muscles to act as controls. RESULTS: All patients proceeded with the injections. Twenty (32%; 95% confidence interval (CI) 20 to 44%) obtained greater than 50% relief of their pain following the administration of saline. Fifty seven patients completed the study; 23 of them (40%; 95% CI 27 to 53%) failed to obtain relief following the injection of saline but obtained relief following one or more intra-articular injections of local anaesthetic. None of the historical features or clinical tests could discriminate those patients with and those without zygapophysial joint pain. CONCLUSION: Pain originating from the zygapophysial joint is not uncommon, but this study failed to find any clinical predictors in patients with such pain.

Aged↗
PubMed1995

Percutaneous radiofrequency neurotomy in the treatment of cervical zygapophysial joint pain: a caution.

Percutaneous radiofrequency neurotomy has been used in the treatment of pain from the cervical zygapophysial joints, but the results have been modest and not compelling. Several factors might account for its apparent poor success rate, including inadequate patient selection, inaccurate surgical anatomy, and technical errors. In an effort to overcome these confounders, we used comparative local anesthetic blocks to preoperatively, definitively diagnose cervical zygapophysial joint pain and developed an amended operative technique based on formal anatomical studies. An audit was conducted of our experience with 19 patients to determine whether there was sufficient merit in the amended procedure to justify a randomized, double-blind, controlled trial. The duration of complete pain relief was the principal outcome measure. Side effects and complications were also monitored. Of the 10 patients who underwent third occipital neurotomy for the treatment of C2-C3 zygapophysial joint pain, only 4 obtained long-lasting relief. The other six patients reported an early return of their pain and constituted technical failures; the third occipital nerve was inadequately coagulated and recovered in the immediate postoperative period. Of the 10 patients who underwent lower cervical medial branch neurotomy, 7 obtained complete pain relief for clinically useful periods and were able to resume their activities of daily living and employment. After procedures at all levels, a brief period of postoperative pain was experienced by the patients and ataxia was a side effect of third occipital neurotomy. There were no cases of postoperative infection or anesthesia dolorosa. Given the high technical failure rate of third occipital neurotomy, we recommend that this procedure be abandoned until the technical problems can be overcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervical Vertebrae↗
PubMed1995

A biological basis for instantaneous centres of rotation of the vertebral column.

The instantaneous centre of rotation has proven to be a useful parameter of vertebral motion. The normal location of instantaneous centres has been determined in cadavers and in normal volunteers for the cervical, thoracic and lumbar spines, and abnormal location of centres has been shown to correlate with spinal pain. However, to date, an instantaneous centre has constituted no more than a convenient mathematical summary of vertebral kinematics. It has defied resolution into biologically meaningful parameters. This study offers a novel model of vertebral motion in which the instantaneous centre of rotation can be shown to be a function of the location of the centre of reaction of a vertebra, and the intrinsic rotation and translation it undergoes. These parameters are strictly linked by equations that determine the location of an axis of rotation. These equations allow aberrations in the location of an axis to be interpreted in terms of the anatomical and pathological factors that affect the centre of reaction of the vertebra and the rotation and translation it undergoes.

Biomechanical Phenomena↗
PubMed1995

Facet joint pain.

Explore the source record for details and available documents.

Adrenal Cortex Hormones↗
PubMed1994

Clinical features of patients with pain stemming from the lumbar zygapophysial joints. Is the lumbar facet syndrome a clinical entity?

STUDY DESIGN: This study is a prospective cross-sectional analytic study. OBJECTIVES: The authors determined the prevalence and clinical features of patients with pain stemming from the lumbar zygapophysial joints. SUMMARY OF BACKGROUND DATA: Previous studies have demonstrated a wide range of prevalence for zygapophysial joint pain and conflicting results with regard to clinical signs. METHODS: One hundred and seventy-six consecutive patients with chronic low back pain were investigated with a series of screening zygapophysial joint blocks using lignocaine and confirmatory blocks using bupivacaine. RESULTS: Forty-seven percent of patients had a definite or greater response to the screening injection at one or more levels but only 15% had a 50% or greater response to a confirmatory block. Response to zygapophysial joint injection was not associated with any single clinical feature or set of clinical features. CONCLUSIONS: The zygapophysial joint is an important source of pain but the existence of a "facet syndrome" must be questioned.

Adult↗
PubMed1994

Lack of effect of intraarticular corticosteroids for chronic pain in the cervical zygapophyseal joints.

BACKGROUND: Chronic pain in the cervical zygapophyseal joints is a common problem after a whiplash injury. Treatment with intraarticular injections of corticosteroid preparations has been advocated, but the value of this approach has not been established. We compared the efficacy of a depot injection of a corticosteroid preparation with the efficacy of an injection of a local anesthetic agent in patients with painful cervical zygapophyseal joints. METHODS: Sixteen men and 25 women with pain in one or more cervical zygapophyseal joints after automobile accidents (mean age, 43 years; median duration of pain, 39 months) were randomly assigned to receive an intraarticular injection of either bupivacaine (0.5 percent) or betamethasone (5.7 mg) under double-blind conditions. The patients were followed by means of regular telephone contact and clinic visits until they reported a return to a level of pain equivalent to 50 percent of the preinjection level. The time from treatment to a 50 percent return of pain was compared in the two groups with the use of a survival analysis. RESULTS: Less than half the patients reported relief of pain for more than one week, and less than one in five patients reported relief for more than one month, irrespective of the treatment received. The median time to a return of 50 percent of the preinjection level of pain was 3 days in the 21 patients in the corticosteroid group and 3.5 days in the 20 patients in the local-anesthetic group (P = 0.42). CONCLUSIONS: Intraarticular injection of betamethasone is not effective therapy for pain in the cervical zygapophyseal joints after a whiplash injury.

Adult↗
PubMed1994

The relative contributions of the disc and zygapophyseal joint in chronic low back pain.

STUDY DESIGN: A prospective cross-sectional analytic approach was taken. OBJECTIVES: This study sought to determine the relative contribution of the disc and the zygapophyseal joint as a pain source in patients with chronic low back pain. SUMMARY OF BACKGROUND DATA: Previous studies have employed either zygapophyseal joint blocks or discography, but in no studies have both procedures been performed. METHODS: Ninety-two consecutive patients with chronic low back pain were studied using both discography and blocks of the zygapophyseal joints. RESULTS: Thirty-six patients (39%) had at least one positive discogram as defined by exact pain reproduction, an abnormal image, and a negative control. Eight patients responded to both a screening zygapophyseal joint block using lignocaine and a confirmatory block using bupivacaine. Only three patients had both a positive discogram and a symptomatic zygapophyseal joint. CONCLUSIONS: In patients with chronic low back pain, the combination of discogenic pain and zygapophyseal joint pain is uncommon.

Adult↗
PubMed1994

The false-positive rate of uncontrolled diagnostic blocks of the lumbar zygapophysial joints.

One hundred and seventy-six consecutive patients with chronic low back pain and no history of previous lumbar surgery were studied to determine the false-positive rate of single diagnostic blocks of the lumbar zygapophysial joints. All patients underwent diagnostic blocks using lignocaine. Those patients who obtained definite or complete relief from these blocks subsequently underwent confirmatory blocks using bupivacaine. Eighty-three patients (47%) had a definite or greater response to the initial, lignocaine injection at one or more levels but only 26 (15%) had a 50% or greater response to a confirmatory injection of 0.5% bupivacaine. Using the response to confirmatory blocks as the criterion standard, the false-positive rate of uncontrolled diagnostic blocks was 38% and the positive predictive value of these blocks was only 31%. Because the positive predictive value of a test is lower when the pre-test probability (prevalence) is low, and because the prevalence of lumbar zygapophysial joint pain is likely to be less than 50%, uncontrolled diagnostic blocks will always be associated with an unacceptably low positive predictive value. These features render uncontrolled diagnostic blocks unreliable for the diagnosis of lumbar zygapophysial joint pain not only in epidemiologic studies but also in any given patient.

Adult↗
PubMed1994

The value of the provocation response in lumbar zygapophyseal joint injections.

OBJECTIVE: To determine the relationship between pain provocation and the analgesic response in lumbar zygapophyseal joint blocks. DESIGN: Consecutive patients undergoing intraarticular zygapophyseal joint blocks for the investigation of low back pain were included in this prospective study. SETTING: The referred sample was from the metropolitan areas of New Orleans and San Francisco. PATIENTS: Ninety patients with low back pain of > 3 months' duration and no history of lumbar surgery. INTERVENTIONS: All patients underwent one or more intraarticular injections of radiographic contrast followed by lignocaine (lidocaine) 2% into zygapophyseal joints between L2-3 and L5-S1. Those with definite responses at one or more levels underwent confirmatory blocks using 0.5% bupivacaine. OUTCOME MEASURES: Provocation of familiar pain and relief of pain after the injection of local anesthetic. Patients were assessed by an independent observer. RESULTS: A total of 203 joints were studied. Adopting liberal criteria, either exact or similar reproduction of pain on the one hand correlated with either definite or complete relief of pain after a single, analgesic block on the other (p < 0.0001). However, when more stringent criteria were adopted, such as response to a confirmatory block using bupivacaine, there was no significant association. CONCLUSIONS: This study calls into question the validity of pain provocation alone as a criterion standard in patients undergoing diagnostic lumbar zygapophyseal joint blocks.

Adult↗
PubMed1994

Third occipital nerve headache: a prevalence study.

A consecutive series of 100 patients was studied to determine the prevalence of third occipital nerve headache in patients with chronic neck pain (> three months in duration) after whiplash. Seventy one patients complained of headache associated with their neck pain. Headache was the dominant complaint of 40 patients, but was only a secondary problem for the other 31. Each patient with headache underwent double blind, controlled diagnostic blocks of the third occipital nerve. On two separate occasions the nerve was blocked with either lignocaine or bupivacaine, in random order. The diagnosis of third occipital nerve headache was made only if both blocks completely relieved the patient's upper neck pain and headache and the relief lasted longer with bupivacaine. The prevalence of third occipital nerve headache among all 100 whiplash patients was 27% (95% confidence interval (95% CI) 18-36%) and among those with dominant headache the prevalence was as high as 53% (95% CI 37-68%). There were no distinguishing features on history or examination that enabled a definitive diagnosis to be made before the nerve blocks. Those patients with a positive diagnosis, however, were significantly more likely to be tender over the C2-3 zygapophysial joint (p = 0.01). Third occipital nerve headache is a common condition in patients with chronic neck pain and headache after whiplash. Third occipital nerve blocks are essential to make this diagnosis.

Adult↗
PubMed1994

Post whiplash syndrome.

Whiplash is a poorly understood problem that attracts accusations of malingering and compensation neurosis. Recent research has revealed a variety of occult lesions that can be responsible for the chronic pain and suffering after whiplash; however, appropriate diagnostic techniques are still either lacking or not widely used. While there are reasonable options for acute management there is no proven therapy for the chronic situation.

Biomechanical Phenomena↗
PubMed1994

Pain from the lumbar zygapophysial joints: a test of two models.

One hundred seventy-six consecutive patients with chronic low-back pain and no history of previous lumbar surgery were studied to test the clinical criteria of Fairbank et al. and Helbig and Lee for zygapophysial joint pain. All patients underwent a history, examination, and a series of zygapophysial joint injections or blocks of the medial branches of the dorsal ramus with lignocaine. Those patients responding to the first series of blocks were given confirmatory blocks using bupivacaine. None of the clinical features tested was found to be associated with response to the confirmatory block. The Fairbank et al. and Helbig and Lee criteria were shown to be unreliable in distinguishing pain of zygapophysial joint origin from pain of other origins.

Adult↗
PubMed1993

The effects of flexion on the geometry and actions of the lumbar erector spinae.

A modeling study was undertaken to determine the effects of flexion on the forces exerted by the lumbar back muscles. Twenty-nine fascicles of the lumbar multifidus and erector spinae were plotted onto tracings of radiographs of nine normal volunteers in the flexion position. Moment arms and force vectors of each fascicle were calculated. The model revealed that moment arms decreased slightly in length resulting in no more than an 18% decrease in maximum extensor moments exerted across the lumbar spine. Compression loads were not significantly different from those generated in the upright posture. However, there were major changes in shear forces, in particular a reversal from a net anterior to a net posterior shear force at the L5/S1 segment. Flexion causes substantial elongation of the back muscles, which must therefore reduce their maximum active tension. However, if increases in passive tension are considered it emerges that the compression forces and moments exerted by the back muscles in full flexion are not significantly different from those produced in the upright posture.

Adult↗
PubMed1993

Intra-articular inclusions of the cervical synovial joints.

Two hundred and ten cervical synovial joints from 15 adult vertebral columns were studied by dissection to determine the form, dispositions and prevalence of intra-articular inclusions. Three types of inclusions were found. Fat pads occurred regularly in the atlanto-occipital joints but rarely in the zygapophysial joints. Capsular rims occurred occasionally at all levels. Fibro-adipose meniscoid occurred regularly in the atlanto-axial and zygapophysial joints. The function of fibroadipose meniscoids seems to be to protect the articular cartilages in gliding joints that subluxate during normal movement. Arguments are raised that these structures may act as a nidus for intra-articular fibrosis, and that meniscus extrapment may be a mechanism for torticollis.

Adipose Tissue↗
PubMed1993

False-positive rates of cervical zygapophysial joint blocks.

OBJECTIVE: To determine the false-positive rate of anesthetic blocks of the medial branches of the cervical dorsal rami in the diagnosis of cervical zygapophysial joint pain. DESIGN: Comparison between single diagnostic blocks, and a criterion standard of double-blind, controlled, differential anesthetic blocks. SETTING: Tertiary referral center. PATIENTS: The first 55 consecutive patients with neck pain for > 3 months after and attributable to a motor vehicle accident, and who had completed a second diagnostic block after an initial positive response. A total of 60 joints was studied, with five patients providing two joints each. The mean age was 41 years; 61% were female. METHODS: Each patient had been investigated with radiologically controlled blocks of the medial branches of the cervical dorsal rami to anesthetize the target cervical zygapophysial joint. The initial block was performed using either 0.5% bupivacaine or 2% lignocaine, randomly selected. The duration of pain relief was assessed in a double-blind fashion. The procedure was repeated with the complementary anesthetic. Only patients experiencing a longer period of pain relief from bupivacaine were considered to have true-positive responses. RESULTS: The second block failed to relieve pain in two of the tested joints. In a further 14 joints, the control blocks relieved pain, but the patient failed to correctly discriminate the longer acting anesthetic. The remaining 44 joints met the criteria for true-positive responses. The false-positive rate of single blocks was 16 of 60 or 27% (95% confidence interval 15%, 38%). CONCLUSIONS: Uncontrolled diagnostic blocks are compromised by a significant false-positive rate that seriously detracts from the specificity of the test.

Accidents, Traffic↗
PubMed1993

The axial torque of the lumbar back muscles: torsion strength of the back muscles.

The maximal, axial torque generated by the lumbar back muscles was determined by modelling the action of the 49 fascicles of longissimus thoracis, iliocostalis lumborum and the lumbar multifidus on radiographs of the lumbar spine of nine young male subjects in upright standing and in full lumbar flexion. No single fascicle exerted more than 2 Nm of axial torque in the upright posture, and the collective torque of all muscles acting a segment did not exceed 5 Nm. All torques were considerably less in full flexion. The lumbar back muscles exert very little torque on the lumbar spine, and contribute only about 5% of the total torque involved in trunk rotation. None of the lumbar back muscles can be considered a rotator. The oblique abdominal muscles are the principal rotators of the trunk. Preventative and rehabilitation programmes concerned with torsion injuries should focus on the abdominal muscles rather than the back muscles for stability in axial rotation.

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