The management of chronic spinal pain by blockades: a review

Human assumed central sensitisation (HACS) in patients with chronic low back pain radiating to the leg (CLaSSICO study)

INTRODUCTION

Patients with chronic low back pain radiating to the leg (CLBPr) are sometimes referred to a specialised pain clinic for a precise diagnosis based, for example, on a diagnostic selective nerve root block. Possible interventions are therapeutic selective nerve root block or pulsed radiofrequency. Central pain sensitisation is not directly assessable in humans and therefore the term 'human assumed central sensitisation' (HACS) is proposed. The possible existence and degree of sensitisation associated with pain mechanisms assumed present in the human central nervous system, its role in the chronification of pain and its interaction with diagnostic and therapeutic interventions are largely unknown in patients with CLBPr. The aim of quantitative sensory testing (QST) is to estimate quantitatively the presence of HACS and accumulating evidence suggest that a subset of patients with CLBPr have facilitated responses to a range of QST tests.The aims of this study are to identify HACS in patients with CLBPr, to determine associations with the effect of selective nerve root blocks and compare outcomes of HACS in patients to healthy volunteers.

METHODS AND ANALYSIS

A prospective observational study including 50 patients with CLBPr. Measurements are performed before diagnostic and therapeutic nerve root block interventions and at 4 weeks follow-up. Data from patients will be compared with those of 50 sex-matched and age-matched healthy volunteers. The primary study parameters are the outcomes of QST and the Central Sensitisation Inventory. Statistical analyses to be performed will be analysis of variance.

ETHICS AND DISSEMINATION

The Medical Research Ethics Committee of the University Medical Center Groningen, Groningen, the Netherlands, approved this study (dossier NL60439.042.17). The results will be disseminated via publications in peer-reviewed journals and at conferences.

TRIAL REGISTRATION NUMBER

NTR NL6765.

Percutaneous Radiofrequency Facet Rhizotomy – Experience with 118 Procedures and Reappraisal of its Value

Background:

There have been many reports of percutaneous radiofrequency facet rhizotomy, perhaps better referred to as facet denervation, usually performed under general anaesthesia, with inconsistent success rates.

Objectives:

To report the authors' outcome data using both general and local anaesthesia and to reassess the value of this controversial procedure.

Methods:

Our experience with 118 consecutive percutaneous radiofrequency facet rhizotomies performed on 90 patients in the Toronto Western Hospital was analyzed. Sixty percent of the procedures were performed under general anaesthesia, 40% under local anaesthesia. All patients had been temporarily virtually relieved of pain after local anaesthetic blockade of the subject facets by an independent radiologist.

Results:

The patients were monitored from 1 - 33 (mean 5.6) months after surgery, with complete elimination or a greater than 50% subjective reduction of pain considered the criteria for success. For the first or only procedure this was 41% overall, 37% in cases done under local anaesthesia, 46% in cases done under general anaesthesia (difference not statistically significant p=0.52). There was no statistically significant difference in success rates for procedures performed in the cervical, thoracic or lumbosacral facets, with unilateral versus bilateral denervations, when two to three as compared with more than three facets were denervated, nor for operations done in patients who had had previous spinal surgery compared with those who had not. Results were not better regardless of whether hyperextension of the spine aggravated the patient's preoperative pain or not, and when the procedures were repeated in the same patient outcomes tended to be consistent, arguing against repetition of failed facet denervations. The morbidity was low, the chief problem being sensory loss and transient neuropathic pain in the distribution of cutaneous branches of posterior rami in the cervical and thoracic areas; mortality was zero.

Conclusions:

Percutaneous radiofrequency facet denervation is simple and safe, still worth considering in patients with disabling spinal pain that fails to respond to conservative treatment. The use of general anaesthesia shortens the operating time and the patient's discomfort without impairing success rate.

Do minimally invasive procedures have a place in the treatment of chronic low back pain?

Chronic low back pain is the leading cause of disability in the industrialized world. Medical and surgical treatments remain costly despite limited efficacy. The field of 'interventional pain' has grown enormously and evidence-based practice guidelines are systematically developed. In this article, the vast, complex and contradictory literature regarding the treatment of chronic low back pain is reviewed. Interventional pain literature suggests that there is moderate evidence (small randomized, nonrandomized, single group or matched-case controlled studies) for medial branch neurotomy and limited evidence (nonexperimental one or more center studies) for intradiscal treatments in mechanical low back pain. There is moderate evidence for the use of transforaminal epidural steroid injections, lumbar percutaneous adhesiolysis and spinal endoscopy for painful lumbar radiculopathy, and spinal cord stimulation and intrathecal pumps mostly after spinal surgery. In reality, there is no gold standard for the treatment of chronic low back pain, but these results appear promising.

The application of percutaneous lysis of epidural adhesions in patients with failed back surgery syndrome

PURPOSE

To investigate the efficacy and the feasibility of application of percutaneous lysis of epidural adhesions in failed back surgery syndrome (FBSS) using a stiff type guide wire and 4F vascular catheter.

METHODS

Ninety two patients with FBSS were randomly divided into two groups, the control group (treated by injection dexamethasone only) and percutaneous lysis of epidural adhesions group. Visual analog scale scores (VAS) and therapeutic evaluation were observed in the preoperative, seven days postoperative, one month and six months postoperative.

RESULTS

VAS scores for pain were significantly reduced in both groups at seven days. The VAS scores were in controlled group at one month, six months was significantly higher than that in epidural lysis group. However, there was no statistical difference in VAS scores of one month and six months when respectively compared to that of before operation in controlled group. Patients on epidural lysis reported clinical effectiveness rate was 50%. Patients on control was 5.26%, there was a statistical difference between two groups.

CONCLUSION

Percutaneous lysis of epidural adhesions by using a stiff type guide wire and 4F vascular catheter is an effective method in the treatment of FBSS and it has a value in clinical application.

Application of pulsed radio frequency to the dorsal horn and dorsal roots

In the world of neuromodulation for pain management, the new multifunctional electrode presented in this article, together with the associated procedure described, considerably extends the range of therapeutic options in the hands of pain physicians. Besides the definite therapeutic effect, the lower rate of complications and side effects, further factors also make this new procedure and device appear an attractive diagnostic and therapeutic modality.

Sciatica and the sacroiliac joint: a forgotten concept

The definition of sciatica is restricted to the pattern and localization of pain, although much emphasis is given to root compression as causative factor. Other sources of similar pain patterns are generally neglected. Despite absence of obligatory neurological signs in radicular syndromes, a number of patients are subjected to extensive, but redundant screenings. In this report, three patients are presented with presumed radicular pain syndromes, whose symptoms finally could be linked to the sacroiliac (SI) joint either via CT and MRI scans or via pain relief by intra-articular injection with local anaesthetics. Possible mechanisms of SI joint-related pain and difficulties in diagnostic specificity of signs and symptoms are discussed.

[Facet blockade, peridural and periradicular pain therapy]

More than 80% of vertebrogenic lumbar pain is unspecific and can only be attributed to a specific anatomic structure with difficulty. The pain can emanate from the intervertebral discs, intervertebral and sacroiliac (SI) joints, musculature, and ligaments. In a maximum of 7% of cases, the pain is radicular (4% due to intervertebral discs and 3% caused by stenoses). In 7-15% of cases, the pain's origin is located in the region of the vertebral joints and in up to 15% in the region of the SI joint. Although the overwhelming majority of pain has no clear structural cause, infiltrations of medications and nerve blockades are frequently employed. The efficacy of these procedures has however not been verified in controlled studies with the exception of epidural injection of corticosteroids for radicular pain. Epidural and epiradicular application of corticosteroids appear to be effective for radicular pain, at least on a short-term basis, although controlled studies have yielded controversial results. The difficulty lies partly in the exact placement at the affected root for applying the medication. This is hardly possible with a caudal injection, while with a lumbar peridural injection and periradicular injections it is only possible under X-ray control or even better CT guidance.

Do diagnostic segmental nerve root blocks in chronic low back pain patients with radiation to the leg lack distinct sensory effects? A preliminary study

BACKGROUND

The present preliminary study documents the effects of a selective nerve root block (SNB) with short or long acting local anaesthetic compared with baseline measurements in patients with chronic low back pain radiating to the leg with maximum pain in one dermatome (L4).

METHODS

Ten consecutive patients underwent 20 controlled SNBs at L4 with ropivacaine 0.25% and lidocaine 1% in a prospective, randomized, double blind, crossover fashion. Baseline measurements included sensory function (assessed by pinprick on both unaffected and painful leg) and pain (Verbal Numeric Rating Scale; VNRS, 0-10). A change in size of areas with altered sensory function >10% and a VNRS change of 2 points were considered clinically significant. P-values<0.05 were considered statistically significant.

RESULTS

Asymptomatic hypoaesthesia, variable in extent and non-dermatomal in distribution, was present in seven patients at baseline. It appeared to be more extensive and distal with longer duration of pre-existing pain. SNB produced no consistent changes in extent and distribution of hypoaesthetic areas. Change in VNRS did not correlate with the extent of pre-block or post-block hypoaesthesia. No differences in effects were found between lidocaine and ropivacaine.

CONCLUSIONS

Pre-block assessment of sensory function is essential to assess the net effect of SNBs. In this small study group, SNBs failed to demonstrate uniform or distinct effects on sensory function.

Cervicogenic headache: practical approaches to therapy

Cervicogenic headache is a relatively common and still controversial form of headache arising from structures in the neck. The estimated prevalence of the disorder varies considerably, ranging from 0.7% to 13.8%. Cervicogenic headache is a 'side-locked' or unilateral fixed headache characterised by a non-throbbing pain that starts in the neck and spreads to the ipsilateral oculo-fronto-temporal area. In patients with this disorder, attacks or chronic fluctuating periods of neck/head pain may be provoked/worsened by sustained neck movements or stimulation of ipsilateral tender points. The pathophysiology of cervicogenic headache probably depends on the effects of various local pain-producing or eliciting factors, such as intervertebral dysfunction, cytokines and nitric oxide. Frequent coexistence of a history of head traumas suggests these also play an important role. A reliable diagnosis of cervicogenic headache can be made based on the criteria established in 1998 by the Cervicogenic Headache International Study Group. Positive response after an appropriate nerve block is an essential diagnostic feature of the disorder. Differential diagnoses of cervicogenic headache include hemicrania continua, chronic paroxysmal hemicrania, occipital neuralgia, migraine and tension headache. Various therapies have been used in the management of cervicogenic headache. These range from lowly invasive, drug-based therapies to highly invasive, surgical-based therapies. This review evaluates use of drug therapy with paracetamol and NSAIDs, infliximab and botulinum toxin type A; manual modalities and transcutaneous electrical nerve stimulation therapy; local injection of anaesthetic or corticosteroids; and invasive surgical therapies for the treatment of cervicogenic headache. A curative therapy for cervicogenic headache will not be developed until increased knowledge of the aetiology and pathophysiology of the condition becomes available. In the meantime, limited evidence suggests that therapy with repeated injections of botulinum toxin type A may be the most safe and efficacious approach. The surgical approach, which includes decompression and radiofrequency lesions of the involved nerve structures, may also provide physicians with further options for refractory cervicogenic headache patients. Unfortunately, the paucity of experimental models for cervicogenic headache and the relative lack of biomolecular markers for the condition mean much is still unclear about cervicogenic headache and the disorder remains inadequately treated.

Lumbar Segmental Nerve Blocks with Local Anesthetics, Pain Relief, and Motor Function: A Prospective Double-Blind Study Between Lidocaine and Ropivacaine

Selective segmental nerve blocks with local anesthetics are applied for diagnostic purposes in patients with chronic back pain to determine the segmental level of the pain. We performed this study to establish myotomal motor effects after L4 spinal nerve blocks by lidocaine and ropivacaine and to evaluate the relationship with pain. Therefore, 20 patients, of which 19 finished the complete protocol, with chronic lumbosacral radicular pain without neurological deficits underwent segmental nerve blocks at L4 with both lidocaine and ropivacaine. Pain intensity scores (verbal numeric rating scale; VNRS) and the maximum voluntary muscle force (MVMF; using a dynamometer expressed in newtons) of the tibialis anterior and quadriceps femoris muscles were measured on the painful side and on the control side. The median VNRS decrease was 4.0 (P < 0.00001; Wilcoxon's signed rank test), without significant differences between ropivacaine and lidocaine (Mann-Whitney U-test). A difference in effect on MVMF was found for affected versus control side (P = 0.016; Tukey test). Multiple regression revealed a significant negative correlation for change in VNRS score versus change in median MVMF (Spearman R = -0.48: P = 0.00001). This study demonstrates that in patients with unilateral chronic low back pain radiating to the leg, pain reduction induced by local anesthetic segmental nerve (L4) block is associated with increased quadriceps femoris and tibialis anterior MVMF, without differences for lidocaine and ropivacaine.

Special techniques in pain management: lysis of adhesions

Low back pain, with or without radicular symptoms, is a common medical condition. It can cause mild to severe suffering, high health costs, and disability. Most sufferers recover quickly and are left without sequelae. The less fortunate group of patients who do not improve despite conservative and mildly interventional therapy, find themselves in search of a more effective treatment. To enhance treatment outcome, an understanding of the pathophysiology of the underlying pain and the design of target-specific treatment modalities is important.

Radiofrequency lesioning using two different time modalities for the treatment of lumbar discogenic pain: a randomized trial

STUDY DESIGN

A prospective randomized trial.

OBJECTIVE

To evaluate the efficacy of percutaneous intradiscal radiofrequency thermocoagulation by modifying the duration of heating, using two different time methods, for relieving pain and improving functional disability.

SUMMARY OF BACKGROUND DATA

Lumbar discogenic pain is the major problem in lumbar degenerative disc disease that percutaneous intradiscal radiofrequency thermocoagulation has been suggested for as a nonsurgical invasive treatment technique for lumbar discogenic pain. In a previous controlled study, this method was found to be ineffective with 8 weeks of follow-up.

MATERIALS AND METHODS

Sixty patients with chronic low back pain were selected for provocative discography to diagnose the discogenic pain and to locate the discs to be treated. From this group, 39 patients were randomly selected and divided into two groups. In the first group, treatment was performed for 120 seconds, and in the second group for 360 seconds, both at 80C. Patients were assessed with a visual analogue scale for pain relief and functional improvement. Evaluations were performed before, immediately after treatment, at 1 and 2 weeks, and at 1, 3, and 6 months after the procedure.

RESULTS

A total of 39 patients with positive provocative discographies were found to eligible for the study. There were no statistical differences in pain relief and functional improvement between two groups (P > 0.05). The immediate, 1-week and 2-week, and 1-month visual analogue scale (VAS) scores were decreased significantly in both groups when comparing them with the pretreatment scores (P < 0.05). However, the final values after 6 months were similar to those measured at the beginning of the study (P > 0.05).

CONCLUSION

Percutaneous intradiscal radiofrequency thermocoagulation has been suggested and performed to relieve discogenic pain. In the previous controlled study, no effective pain relief has been obtained. In this study, the authors increased the duration of radiofrequency thermocoagulation to improve the effectiveness of this method. Yet, the authors have not found any significant differences between the application of lesioning at two different times in percutaneous intradiscal radiofrequency thermocoagulation.

Does neural blockade and other neurosurgical modalities offer a durable pain relief for spinal disorders?

Various minimally invasive techniques have been performed to fight pain originating at bony and soft tissue spine elements. Of these, denervation of the nerve supply to the facet joints is the only technique for which three multidisciplinary clinical studies have been conducted, according to state-of-the-art study criteria, to produce evidence-based efficacy data. Of all of the morphopathological factors contributing to chronic spinal pain, facet joints play a major role in generating spinal pain due to hypermobility or joint degeneration. This is commonly referred to as facet joint syndrome (FJS). Other important non-morphological co-morbidity factors (mostly psychiatric, social or occupational in origin) also play an important role in mediating spinal pain. From the existing evidence-based data, there seems to be no durable pain relief in FJS using standard lesioning techniques (thermal and/or cryo). Efficacy compared to placebo lasts for only 4 weeks. Only those patients with spinal canal stenosis and concomitant chronic FJS appear to benefit after microsurgical decompression of the narrowed spinal canal. However, the database for this claim is low since low back pain is not the major focus in the clinical symptoms reported by the patients.

Cervicogenic headache: diagnostic evaluation and treatment strategies

Cervicogenic headache is a chronic, hemicranial pain syndrome in which the source of pain is located in the cervical spine or soft tissues of the neck but the sensation of pain is referred to the head. The trigeminocervical nucleus is a region of the upper cervical spinal cord where sensory nerve fibers in the descending tract of the trigeminal nerve converge with sensory fibers from the upper cervical roots. This convergence of upper cervical and trigeminal nociceptive pathways allows the referral of pain signals from the neck to the trigeminal sensory receptive fields of the face and head. The clinical presentation of cervicogenic headache suggests that there is an activation of the trigeminovascular neuroinflammatory cascade, which is thought to be one of the important pathophysiologic mechanisms of migraine. Another convergence of sensorimotor fibers has been described involving intercommunication between the spinal accessory nerve (CN XI), the upper cervical nerve roots, and ultimately the descending tract of the trigeminal nerve. This neural network may be the basis for the well- recognized patterns of referred pain from the trapezius and sternocleidomastoid muscles to the face and head. Diagnostic criteria have been established for cervicogenic headache but its presenting characteristics may be difficult to distinguish from migraine, tension-type headache, or hemicrania continua. A multidisciplinary treatment program integrating pharmacologic, nonpharmacologic, anesthetic, and rehabilitative interventions is recommended. This article reviews the clinical presentation of cervicogenic headache, its diagnostic evaluation, and treatment strategies.

A rationale for the treatment algorithm of failed back surgery syndrome

Failed back surgery syndrome is continued low back pain with or without radicular pain after lumber surgery. The syndrome is difficult to treat due to the variability of pain generators. By examining the anatomy and pathophysiology of the pain mechanisms, a logical progression for an algorithm for treatment is presented.

Myelinated fibers of spinal cord blood vessels--sensory innervation?

Innervation of the ventral spinal artery from the lumbosacral region of dogs was studied using light, scanning, and transmission microscopy. Microscopy revealed myelinated fibers, a new observation, in addition to unmyelinated fibers expected on the basis of previous studies of autonomic innervation of this blood vessel. The myelinated axons may be sensory fibers.

Selective Spinal Injections for Lower Back Pain

Tremendous progress has been made in the understanding of neural pathways and tissues involved in back pain, and new treatment techniques for back pain have evolved. This article focuses on a technique called epidural neuroplasty (lysis of epidural adhesions). Originally performed as a single-catheter technique using the caudal approach, this technique now features a number of variations. These variations include emphasis on anterior placement of the catheter tip, use of a transforaminal approach, and use of one or two catheters.

Elevated detection thresholds for mechanical stimuli in chronic pain patients: support for a central mechanism

OBJECTIVE

To investigate the relation between pain provoking cervical segments identified by diagnostic dorsal root blockades and elevation of detection thresholds in patients suffering from chronic cervicobrachialgia (CCB).

DESIGN

Quantitative sensory testing (light touch) of the cervical dermatomes using Semmes-Weinstein monofilaments.

SETTING

A university pain clinic.

SUBJECTS

Thirty-nine patients with CCB, with no clinical or diagnostic evidence of radiculopathy or surgically treatable bony lesion and with one main pain-provoking cervical segment identified by diagnostic dorsal root blockades.

OUTCOME MEASURES

Detection thresholds with 95% confidence intervals (95% CI) of pain-provoking segments, compared with surrounding and contralateral segments and with normal values for cervical dermatomes.

RESULTS

Patients' detection thresholds were significantly (p < .001) higher than those for normal subjects: 3.51 (95% CI, 2.71-4.31) and 3.10 (95% CI, 2.34-3.86), respectively. No significant differences existed between the segments. The elevations were systematic. However, thresholds on the painful side were consistently, slightly higher than those on the contralateral side.

CONCLUSION

Supporting earlier studies, results from CCB patients in the present study showed systematic elevation of detection thresholds (low threshold mechanoreceptors), an adaptation in contrast with, but not contradictory to, central sensitization of high threshold neurons in chronic pain.

Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain

STUDY DESIGN

A prospective double-blind randomized trial in 31 patients.

OBJECTIVES

To assess the clinical efficacy of percutaneous radiofrequency denervation of the lumbar zygapophysial joints in reducing pain, functional disability, and physical impairment in patients with back pain originating from the lumbar zygapophysial joints.

SUMMARY OF BACKGROUND DATA

Chronic low back pain is a major health problem in the industrialized world. A treatment option is percutaneous radiofrequency denervation of the lumbar zygapophysial joints. Its clinical efficacy has never been formally tested in a controlled trial.

METHODS

Thirty-one patients with a history of at least 1 year of chronic low back pain were selected on the basis of a positive response to a diagnostic nerve blockade and subsequently randomly assigned to one of two treatment groups. Each patient in the radiofrequency treatment group (15 patients) received an 80 C radiofrequency lesion of the dorsal ramus of the segmental nerve roots L3, L4, and L5. Patients in the control group (n = 16) underwent an the same procedure but without use of a radiofrequency current. Both the treating physician and the patients were blinded to the group assignment. Before treatment, physical impairment, rating of pain, the degree of disability, and quality of life were assessed by a blinded investigator.

RESULTS

Eight weeks after treatment, there were 10 success patients in the radiofrequency group (n = 15) and 6 in the sham group (n = 16). The unadjusted odds ratio was 3.3 (P = 0.05, not significant), and the adjusted odds ratio was 4.8 (P < 0.05, significant). The differences in effect on the visual analog scale scores, global perceived effect, and the Oswestry disability scale were statistically significant. Three, 6, and 12 months after treatment, there were significantly more success patients in the radiofrequency group compared with the sham group.

CONCLUSIONS

Radiofrequency lumbar zygapophysial joint denervation results in a significant alleviation of pain and functional disability in a select group of patients with chronic low back pain, both on a short-term and a long-term basis.

Innervation of "painful" lumbar discs

STUDY DESIGN

The authors investigated the innervation of discographically confirmed degenerated and "painful" human intervertebral discs.

OBJECTIVE

To determine the type and distribution patterns of nerve fibers present in degenerated human intervertebral discs.

SUMMARY OF BACKGROUND DATA

The innervation of intervertebral discs has previously been extensively described in fetal and adult animals as well as humans. However, little is yet known about the innervation of severely degenerated human lumbar discs. The question may be posed whether a disc that has been removed for low back pain possesses an increased innervation compared with normal discs.

METHODS

The presence of nerve fibers was investigated using acetylcholinesterase enzyme histochemistry, as well as neurofilament and substance P immunocytochemistry. From 10 degenerated and 2 control discs, the anterior segments were excised and their nerve distribution studied by examining sequential sections.

RESULTS

In all specimens, nerve fibers of different diameters were found in the anterior longitudinal ligament and in the outer region of the disc. In 8 of 10 degenerated discs, fibers were also found in the inner parts of the disc. Substance P-immunoreactive nerve fibers were sporadically observed in the anterior longitudinal ligament and the outer zone of the anulus fibrosus.

CONCLUSIONS

Findings indicate a more extensive disc innervation in the severely degenerated human lumbar disc compared with normal discs. The nociceptive properties of at least some of these nerves are highly suggested by their substance P immunoreactivity, which provides further evidence for the existence of a morphologic substrate of discogenic pain.

Intravenous phentolamine test--an aid in the evaluation of patients with persistent pain after low-back surgery?

BACKGROUND

Persistent pain following surgery in the treatment of chronic low-back pain patients is still relatively frequent. Most of these patients with persistent pain have clinical signs of neuropathic pain. The neuropathic pain might be sympathetically maintained pain (SMP) or sympathetically independent pain (SIP). Systemic administration of phentolamine, a competitive alpha-adrenergic antagonist, has been used as a diagnostic tool to identify patients with SMP.

METHODS

Thirty-seven patients with persistent pain after low-back surgery (lumbar laminectomy, with or without discectomi, or a posterior fusion, with or without decompression) received intravenous phentolamine (0.5 mg/kg over 30 min) in a single-blind, placebo-controlled manner. Prior to this infusion the patients were classified clinically into different pain groups based on physical examination and imaging findings. An opioid epidural test blockade was used as a control.

RESULTS

Clinical classification divided the patients into nociceptive pain (n = 7), neuropathic pain (n = 22) and mixed pain (n = 8). In the phentolamine test there were only one responder, 34 non-responders and 2 patients were placebo-responders. In the control epidural blockade there were 11 non-responders, 23 fentanyl/local anaesthetic-responders and 3 placebo-responders.

CONCLUSIONS

SMP is either an uncommon cause of persistent pain in this type of failed back surgery patients or the phentolamine test, as we performed it, was unable to identify SMP.

Temporomandibular and cervical spine disorders. Self-reported signs and symptoms

STUDY DESIGN

The authors assessed the results of an anamnestic self-administered questionnaire given to 111 patients with temporomandibular disorders and 103 patients with cervical spine disorders.

OBJECTIVES

The present study was performed to investigate whether patients with cervical spine disorders and subgroups of patients with temporomandibular disorders differ regarding specific and accompanying signs and symptoms of temporomandibular disorders and cervical spine disorders.

SUMMARY OF BACKGROUND DATA

Patients with temporomandibular disorders frequently show signs and symptoms related to cervical spine disorders, and, vice versa, patients with cervical spine disorders may show signs and symptoms related to temporomandibular disorders. Many authors have pointed out the existence of neuroanatomical and biomechanical relationships.

METHODS

The questionnaire included questions about pain, symptoms of temporomandibular disorders, accompanying signs and symptoms, psychosocial factors, and general health. Before their clinical examination, all patients were requested by mail to complete the questionnaire.

RESULTS

Patients with cervical spine disorders reported fewer symptoms of temporomandibular disorders than the subgroups of patients with temporomandibular disorders, more general health symptoms than patients with temporomandibular disorders with an arthrogenous or myogenous component, and fewer ear symptoms than patients with temporomandibular disorders. There was no difference between the patient groups regarding other associated signs and symptoms and psychosocial factors as measured with the questionnaire. Logistic regression analyses showed that six variables (jaws, ears, eyes, temporomandibular joint sounds, complaints of the shoulders, and pain in joints other than the temporomandibular joint) correctly classified 91% of the patients as having temporomandibular disorders or cervical spine disorders.

CONCLUSIONS

The results of this study do not support the theoretical concept that cervical spine disorders may give rise to temporomandibular disorders. The authors' results indicate that the anamnestic questionnaire can be used as an aid to distinguish patients with cervical spine disorders from subgroups of patients with temporomandibular disorders.

Specificity of diagnostic nerve blocks: a prospective, randomized study of sciatica due to lumbosacral spine disease

Temporary nerve blocks using local anesthetic are employed extensively in the evaluation of pain problems, particularly lumbosacral spine disease. Their specificity and sensitivity in localizing anatomic sources of pain have never been studied formally, however, and so their diagnostic and prognostic value is questionable. There have been anecdotal reports of relief of pain by temporary blocks directed to areas of pain referral, as opposed to areas of documented underlying pathology; but there has been no study to define the frequency or magnitude of this effect. We have examined the specificity and sensitivity of a battery of local anesthetic blocks in a series of 33 patients with a chief complaint of sciatica, attributable in all cases to spinal disease (radiculopathy, with some clinical features of arthropathy). As determined by blinded patient analog ratings in randomized sequence, three different nerve blocks were significantly more effective than control lumbar subcutaneous injection of an identical volume of 3 ml of 0.5% bupivacaine (P < 0.05). Not only paraspinal lumbosacral root blocks and medial branch posterior primary ramus blocks (at or proximal to the pathology), but also sciatic nerve blocks (distal or collateral to the pathology) produced temporary relief in a majority of patients. This confirmed the study hypothesis that false positive results are common, and specificity is low. For sciatic nerve blocks, specificity was between 24% and 36%. Patterns of responses specific to the established diagnosis of radiculopathy (i.e., root block most effective) had sensitivities between 9% and 42%. Statistical analysis of clinical and technical prognostic factors revealed that the only association with pain relief by any block were the effects of other blocks. The strongest association was between relief by sciatic nerve block and relief by medial branch posterior primary ramus (facet) block (P = 0.001, odds ratio 16.0). There were no associations between the results of blocks and clinical findings (history, physical examination, diagnostic imaging) in these patients, chosen for their homogeneous clinical presentation and absence of functional signs. Our findings indicate a limited role for uncontrolled local anesthetic blocks in the diagnostic evaluation of sciatica and referred pain syndromes in general. Negative blocks or a pattern of responses may have some predictive value, but isolated, positive blocks are non-specific. This lack of specificity may, however, be advantageous in therapeutic applications.