- Email: [email protected]
Interscalene brachial plexus block for scapular and upper chest pain due to cervical radiculopathy: a randomized controlled clinical trial
J Orthop Sci (2012) 17:515–520 DOI 10.1007/s00776-012-0248-2
ORIGINAL ARTICLE
Interscalene brachial plexus block for scapular and upper chest pain due to cervical radiculopathy: a randomized controlled clinical trial Yasuaki Murata • Kohichi Kanaya • Hiroyoshi Wada • Keiji Wada • Masahiro Shiba Satoshi Hatta • Ken Kato • Yoshiharu Kato
•
Received: 4 February 2012 / Accepted: 15 May 2012 / Published online: 25 July 2012 Ó The Japanese Orthopaedic Association 2012
Abstract Background Animal experiments have shown that one of the pathways for pain originating from the cervical spine is the sympathetic trunk. However, there have been few reports regarding the cervical pain pathway and efficacy of interscalene brachial plexus block for upper limb, scapular and chest pain originating in the cervical spine in clinical cases. The purpose of the present study was to clarify the efficacy of interscalene brachial plexus block for upper limb, scapular and chest pain. Methods Patients (137 men and 223 women) who had cervical radicular pain were studied. The intensity of upper limb, scapular and chest pain was measured by using a VAS before injection and at 5 min and 7 days after injection. To evaluate the efficacy of interscalene brachial plexus block, patients with cervical radicular pain who had received NSAIDs for at least 2 weeks were randomized to interscalene brachial plexus block or control block groups. VAS scores were compared to assess the effects of injection and the pain pathway. Results The average VAS score for upper limb pain with or without scapular and chest pain was significantly reduced by interscalene brachial plexus block compared with control block at 5 min and 7 days after injection. After interscalene brachial plexus block, 89 patients reported symptoms of stellate ganglion block versus no patients after control block. Scapular and chest pain was
Y. Murata (&) K. Kanaya H. Wada K. Wada M. Shiba S. Hatta K. Kato Y. Kato Department of Orthopaedic Surgery, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjyuku-ku, Tokyo 162-8666, Japan e-mail: [email protected]
significantly reduced in the patients with stellate ganglion block compared to those without stellate ganglion block. Conclusions Interscalene brachial plexus block is useful for upper limb, scapular and chest pain due to disorders of the cervical spine. The scapular and chest pain pathway is more likely to be interrupted by an interscalene brachial plexus block that causes a stellate ganglion block compared to an interscalene brachial plexus block without stellate ganglion block.
Introduction Compression to the cervical spinal nerve can cause radicular pain in the upper limb. Cervical radiculopathy patients sometimes experience scapular and/or chest pain that is actually caused by disorders of the cervical spine and is thought to be referred from cervical structures [1]. Scapular pain mainly occurs in the T1 and/or T2 dermatomes, which are innervated by the dorsal rami of the T1 and/or T2 spinal nerves [2]. Chest pain that occurs in the area innervated by the T1 and/or T2 ventral rami is also occasionally accompanied by radicular pain [2]. Impulses from the cervical spinal nerves that are transmitted segmentally can cause upper limb pain and/or numbness, but these nerves do not innervate the scapula and chest on the dermatome. We hypothesized that the convergence-projection theory could be applied to scapular and chest pain. The theory is based on the anatomical finding that both visceral and somatic afferent fibers synapse with the same dorsal horn cells [3–7]. Interscalene brachial plexus block (IBPB) has been attempted clinically for the management of pain [8, 9]. However, there have been few reports regarding the efficacy and pain relief mechanisms of IBPB for upper limb,
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scapular and chest pain originating in the cervical spine in clinical cases. The purpose of this study was to clarify the efficacy of IBPB for cervical radicular pain, including upper limb, scapular and chest pain, considering the relation between the above-mentioned pain pathway and scapular and chest pain originating from the cervical spine.
Materials and methods To evaluate the efficacy of the IBPB, 360 patients (137 men and 223 women) who had cervical radicular pain were randomized to an IBPB group (n = 180) and a control block group (n = 180). A total of 20 patients dropped out of the study. All of the subjects had been treated with non-steroidal anti-inflammatory drugs (NSAIDs) for at least 2 weeks before enrollment and agreed to undergo the present prospective study. Demographic data were collected, including the age, gender, past medical history, location of pain and visual analog scale (VAS) severity of pain. There were no statistically significant differences between the IBPB and control group regarding these demographic data. The inclusion criteria for the study were patients with cervical radicular pain that had been treated with NSAIDs for at least 2 weeks, and who still had intolerable radicular pain with or without scapular and/or chest pain. When patients complained of ipsilateral upper limb pain along with a segmental region, we suspected radicular pain and diagnosed the pain according to the following procedure. The existence of pain region was diagrammed by interview. Physical examinations, including Spurling’s test, Jackson’s test, manual muscle testing, deep tendon reflex and pin prick test, were performed to identify the disturbed spinal nerve root. When Spurling’s test and/or Jackson’s test provoked segmental pain (positive sign), as a rule MRI was performed to confirm the nerve compression due to degenerative changes. CT was performed to clarify nerve compression due to degenerative change, including bony spars, instead of MRI for patients who were unable to undergo MRI. When the nerve was compressed by or in contact with degenerative tissue on axial images, the MRI or CT examination was considered positive. When the neurological findings were consistent with image results, patients were diagnosed as having radiculopathy. The exclusion criteria were previous spinal surgery, fresh spinal fracture, metastasis of malignant tumor and infections. Myelopathy patients were also excluded in the present study. Although more than half of the patients received non-operative treatment, such as injections and/or medications, after the study period, none of the patients received any additional injections during the study period. After a diagnosis of cervical spine radiculopathy was made, the patients were randomly assigned by one of the authors to either the IBPB group or the control block group
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by using sealed cards. All procedures were approved by the local ethics committee. Patients underwent either IBPB or control block. IBPB was performed by the same medical doctor as described by Winnie [10]. With the patient in the supine position, the posterior edge of the sternocleidomastoid muscle, the scalene hiatus and cricoid cartilage were confirmed to determine the injection point. The head was turned to the opposite side of the application; then a horizontal line was drawn from the cricoid cartilage to the interscalene groove. At the intersection of this line with the posterior edge of the sternocleidomastoid muscle, a 23-G needle was inserted and advanced in the caudal, medial and posterior directions to elicit upper limb muscle contraction and to provoke pain in the upper limb on the ipsilateral side. After contraction and pain had been evoked, a mixture of 7 ml of 1 % lidocaine and 3.3 mg of dexamethasone sodium phosphate was injected. For control block, a 23-G needle was inserted into the trapezius muscle on the ipsilateral side to a depth of 1.5 cm from the skin, and a mixture of 7 ml of 1 % lidocaine and 3.3 mg of dexamethasone sodium phosphate was injected. The intensity of radicular pain with/without scapular and chest pain was measured using the VAS before injection and at 5 min and 7 days after injection. VAS scores were measured by co-medical staff. The time for which the patient experienced no pain or pain that was tolerable without NSAIDs, i.e., the duration of an adequate therapeutic effect, was also determined. When patients showed ptosis 5 min after injection, we defined it as stellate ganglion block (SGB) effect. Statistical methods Visual analog scale scores were compared for patients in the IBPB and control group, and in the IBPB with and without SGB groups before injection and 5 min and 7 days after injection. Between-group differences were analyzed using analysis of variance (ANOVA). A p value less than 0.05 was considered statistically significant.
Results In total, 360 patients were diagnosed as cervical radiculopathy. There was no statistically significant difference between men and women with regard to the previous VAS (83 ± 24 mm for men and 82 ± 26 mm for women). The mean age of the subjects was 55 ± 13 years (range 39–90 years) in the IBPB group and 57 ± 15 years (43–93 years) in the control block group. The mean age of the men and women was 54 ± 9 and 55 ± 14 years, respectively. The average period that the patients had suffered from
Interscalene brachial plexus block
Fig. 1 Mean VAS (±SD) scores before injection and at 5 min and 7 days after injection. The mean VAS scores at 5 min (p \ 0.0001) and 7 days (p \ 0.0001) after injection were significantly lower in the IBPB group than in the control block group. There was no significant difference between the two groups before injection
radicular pain was 15 ± 17 months in the IBPB group and 14 ± 18 months in the control block group. There were no statistically significant differences in these variables between the two groups. The average VAS scores before injection and at 5 min and 7 days after injection are shown in Fig. 1. The average values at 5 min (p \ 0.0001) and 7 days (p \ 0.0001) after injection were significantly lower in the IBPB group than in the control block group. No statistically significant difference was observed between the two groups with regard to the VAS scores before injection. In the IBPB group, 80 patients reported an adequate therapeutic effect at 1 month after injection, and 9 of these patients reported that the effect persisted for more than 3 months (Fig. 2). In the control block group, 23 patients reported an adequate therapeutic effect after 1 month, and 7 of these patients reported that the effect persisted for more than 3 months (Fig. 2). Although a significantly larger number of patients reported a therapeutic effect of IBPB at 1 month, the difference was not statistically significant at 3 months. The average duration of an adequate effect in the IBPB and control block groups was 1.4 ± 2.4 and 0.9 ± 2.4 months, respectively, and the difference was statistically significant (p \ 0.05, Fig. 3). There were no statistically significant differences in pain scores between men and women. A total of 89 patients in the IBPB group versus no patients in the control block group showed the side effect of SGB. The average duration of an adequate effect of IBPB with and without SGB was 2.0 ± 3.1 and 0.7 ± 0.8 months, respectively, and the difference between these subgroups was statistically significant (p \ 0.001,
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Fig. 2 Number of patients with no pain or pain that was tolerable without NSAIDs. A significantly larger number of patients reported a therapeutic effect of IBPB at 1 month, but the difference was no longer significant at 3 months
Fig. 3 The average time (±SD) for which patients had no pain or pain that was tolerable without NSAIDs. The difference between the IBPB and control block groups was statistically significant (p \ 0.05). The difference between IBPB with and without SGB was also statistically significant (p \ 0.001)
Fig. 3). There were no statistically significant differences between IBPB with and without SGB regarding the age, gender, past medical history and location of pain. The average VAS scores before injection and at 5 min and 7 days after the injection are shown in Fig. 4. The average scores at 5 min (p \ 0.05) and 7 days (p \ 0.05) after injection were significantly lower for the IBPB patients with SGB than for those without SGB. No statistically significant difference was observed between these subgroups with regard to the VAS scores before injection. A total of 82 patients had scapular or chest pain (57 to the scapular region and 25 to the chest) in the IBPB group. With regard to this referred pain, the average VAS scores before injection and at 5 min and 7 days after injection are shown in Fig. 5. The average score at 5 min after injection
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to chest pain, the average VAS scores before injection and at 5 min and 7 days after injection were 66, 8 and 36, respectively, when IBPB was accompanied with SGB, and 69, 10 and 47 when IBPB was not accompanied with SGB. Trachyphonia, palpitations, constipation, hematoma and nausea occurred in six patients as side effects. One patient suffered from pneumothorax caused by the needle, and was hospitalized for 2 weeks to receive treatment. No infection developed throughout the observation period.
Discussion
Fig. 4 Mean VAS (±SD) scores before injection and at 5 min and 7 days after injection for the IBPB patients with SGB and without SGB. The mean scores at 5 min (p \ 0.05) and 7 days (p \ 0.05) after injection were significantly lower for the IBPB patients with SGB than for those without SGB. No statistically significant difference was observed between these two subgroups before injection
Fig. 5 Mean VAS (±SD) scores before injection and at 5 min and 7 days after injection for the patients who had pain in the scapular region and/or upper chest and received IBPB with or without SGB. The mean scores 5 min after injection were significantly lower in the patients who had IBPB with SGB than in those without SGB (p \ 0.05). There was no statistically significant difference between these subgroups before injection
was significantly lower in the case of IBPB with SGB than for IBPB without SGB (p \ 0.05). There was no statistically significant difference in the VAS score before injection between the two subgroups. As for scapular pain, the average VAS scores before injection and at 5 min and 7 days after injection were 85, 18 and 51, respectively, when IBPB was accompanied with SGB, and 84 28, and 53 when IBPB was not accompanied with SGB. With regard
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In this study, a total of 89 patients in the IBPB group showed symptoms of SGB. In patients who had scapular or chest pain, the average VAS scores at 5 min after injection were significantly lower when IBPB was associated with SGB than when IBPB was not associated with SGB. Namely, the scapular and chest pain pathway was more likely to be blocked by IBPB associated with SGB. As has been shown by previous animal experiments, it can be presumed that the afferent pathways for referred pain originating from cervical spinal nerves involve the sympathetic trunk via sympathetic afferents in humans, too [11]. Interscalene brachial plexus block is used in upper limb surgery for anesthesia and postoperative analgesia. Neural complications and pneumothorax are a major concern of anesthetists performing IBPB. According to Winnie [10], the block needle direction is perpendicular to all planes at the entry point of the skin. Modifications of IBPB techniques are described in the literature. Some authors encourage a more caudad needle angulation to minimize potential entry into the spinal canal. According to the previous reports, the success of IBPB is owing to the dose of anesthetic [12, 13]. Most commonly 20–40 ml of anesthetic is used to provide a sufficient block of the brachial plexus. It has been reported that the 40 ml injected solution extends a greater distance up and down the sheath than the 20 ml injection by taking X-rays after the injection of anesthetic with contrast medium [10]. However, a very low volume of local anesthetic seems to provide a more selective block of the upper cervical plexus without complete anesthesia of the lower part derived from the C8/Th1 roots [12]. In the present study, a total of 8 ml of anesthetic was used for IBPB. Although we could not present the information about the spread of anesthetic, most likely the plexus was not completely anaesthetized in all patients considering the low volume used in the study. It has been reported that scapular and chest pain can be caused by disorders of the cervical spine and referred from cervical structures [1, 14–18]. Such referred pain is distributed to the dermatome of the dorsal rami of the cervical spinal nerves and to the T1 and T2 dermatomes. The
Interscalene brachial plexus block
suprascapular nerve arises from the C4, C5 and C6 spinal nerves to innervate the supraspinous and infraspinous fossae of the scapular, and is sometimes blocked clinically for the treatment of neck and shoulder pain. However, some referred pain manifests below cervical dermatomes. Such referred pain does not occur in the territory of the cervical spinal nerves, but in the T1 and/or T2 dermatomes. Some clinicians have reported that SGB at the injection level of the C6 vertebra produced successful effects for headache and neck pain and less success for the upper limbs. On the contrary, SGB at the injection level of the C7 vertebra showed successful effects for the upper limbs [19– 21]. SGB at the injection level of T2 was more successful for the upper limbs, including the scapula [22, 23]. These facts may be related to the anatomical structure of the white rami communicantes. The efferent pathway from the cervical spinal nerves to the sympathetic trunk is provided by the gray rami communicantes (Fig. 6a) [24, 25]. However, there are no white rami communicantes to act as the afferent pathway from the sympathetic trunk to the cervical spinal nerves. The white rami communicantes are only connected to the spinal nerves from T1 to L2. It is reasonable to consider that pain signals originating from the cervical spine that enter the sympathetic trunk reach the spinal cord via the shortest pathways, so the white rami communicantes of T1 would be the likely pathway (Fig. 6b).
Fig. 6 Efferent pathway from the spinal nerves to the sympathetic trunk, and afferent pathway from the sympathetic trunk to the spinal nerves. a The gray rami communicantes from cervical to sacral levels provide an efferent pathway. The afferent pathway is provided by the white rami communicantes, which only exist from T1 to L2. ST sympathetic trunk, R ramus communicans, SN spinal nerve. b Pain signals from the cervical spine can be transmitted to the sympathetic trunk via the gray rami communicantes. The shortest pathway for these signals to reach the spinal cord is via the white rami communicantes of T1
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One of the blockades of sympathetic efferent nerve fibers, SGB, has been used clinically for the management of painful conditions such as cephalic, facial and upper limb pain caused by insufficient blood supply to the upper limbs, frostbite, acute vessel spasms, complex regional pain syndrome, hemicrania and trigeminal neuralgia [26]. The stellate ganglion consists of the T1 and inferior cervical sympathetic ganglia. It is usually located in front of the C7 vertebra between the longus coli muscle and the anterior scalene muscle. SGB is performed using local anesthetic, opioids and/or steroids. This procedure can be performed blindly or under fluoroscopic guidance at the anterior tubercle of the C6 vertebra. Complications of SGB include complications related to the technique, infection and pharmacological complications related to the drugs utilized. The mechanism of SGB effects has generally been explained by increased blood flow as a result of peripheral vasodilation, resulting in neural inhibition of the sphere innervated by sympathetic efferent nerve fibers. However, the wide ranges of conditions that respond to SGB suggest that its effectiveness may not be solely the result of increased blood flow. It has been suggested that the effects may be due to influences on sensory mechanisms and sympathetic efferent impulses depolarizing nociceptive afferent fibers [27]. Uchida et al. [28] theorized that melatonin-related dysrhythmias are the result of chronically increased sympathetic nerve tone, which eventually causes decreased functioning of pinealocytes and leads to reduction of plasma melatonin levels. According to their reports, SGB may interrupt the sympathetic cycle, allowing the normal melatonin rhythm to be re-established. The underlying mechanism of pain relief seen in SGB is not totally understood. We acknowledge that our results are limited by incomplete blinding. The clinicians knew who had received IBPB because the subjects were clinical patients. However, as the patients did not know the exact character of the injection during the observation periods, pain relief seemed to be responded to blindly. Although the same amount of saline injection to the interscalene brachial plexus may be the best way to blind patients, this injection creates ethical problems for clinical cases. Thus, we injected the same anesthetic solution to the trapezius muscle, which is near the IBPB injection point. From the present results, it can be concluded that IBPB is useful for reducing radicular pain, including scapular and chest pain, due to disorders of the cervical spine, and the scapular and chest pain pathway is more likely to be interrupted by IBPB associated with SGB than by IBPB without SGB. Some afferent fibers of the pathway for cervical pain may run in the T1 and/or T2 spinal nerves, to which impulse are presumably transmitted via sympathetic afferents.
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Y. Murata et al. The authors declare that they have no conflict 14.
References 1. Schellhas K, Smith M, Gundry CR, Pollei SR. Cervical discogenic pain: prospective correlation of magnetic resonance imaging and discography in asymptomatic subjects and pain sufferers. Spine. 1996;21:300–11. 2. Foerster O. The dermatomes in man. Brain. 1933;56:1–39. 3. Ammons WS. Characteristics of spinoreticular and spinothalamic neurons with renal input. J Neurophysiol. 1987;58:480–95. 4. Cervero F, Connell LA, Lawson SN. Somatic and visceral primary afferents in the lower thoracic dorsal root ganglia of the cat. J Comp Neurol. 1984;228:422–31. 5. Cervero F, Tattersall JE. Cutaneous receptive fields of somatic and viscerosomatic neurones in the thoracic spinal cord of the cat. J Comp Neurol. 1985;237:325–32. 6. Ruch TC. Pathophysiology of pain. In: Fulton JF, editor. A textbook of physiology. 17th ed. Philadelphia: WB Saunders; 1955. p. 358–76. 7. Yokota T, Koyama N, Nishikawa Y, Hasegawa A. Dual somatosensory representation of the periodontium in nucleus ventralis posteromedialis of the cat thalamus. Brain Res. 1988; 475:187–91. 8. Ikeda Y, Lee M, Ebata T, Ogasawara A. Application of interscalene brachial plexus block for upper extremity and shoulder girdle pain. Seikeigeka. 1993;44:1871–4. 9. Murakami H, Lee M, Mimura M, Ohtake Y, Ikeda Y. Application of interscalene brachial plexus block for cervical spondylotic radiculopathy. 1997;48:1191–94. 10. Winnie AP. Interscalene brachial plexus block. Anesth Analg. 1970;49:455–66. 11. Ohtori S, Takahashi K, Chiba T, Yamagata M, Sameda H, Moriya H. Sensory innervation of the cervical facet joints in rats. Spine. 2001;26:147–50. 12. Coleman MM, Chan VW. Continuous interscalene brachial plexus block. Can J Anaesth. 1999;46(3):209–14. 13. Liguori GA, Zayas VM, YaDeau JT, Kahn RL, Paroli L, Buschiazzo V, Wu A. Nerve localization techniques for interscalene brachial plexus blockade: a prospective, randomized comparison
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of mechanical paresthesia versus electrical stimulation. Anesth Analg. 2006;103:761–7. Cloward RB. Cervical diskography: a contribution to the etiology and mechanism of neck, shoulder and arm pain. Ann Surg. 1959; 150:1052–64. Dwyer A, Aprill C, Bogduk N. Cervical zygapophyseal joint pain patterns I: a study in normal volunteers. Spine. 1990;15:453–7. Fukui S, Ohseto K, Shiotani M, Ohno K, Karasawa H, Naganuma Y, Yuda Y. Referred pain distribution of the cervical zygapophyseal joints and cervical dorsal rami. Pain. 1996;68:79–83. Grubb SA, Kelly CK. Cervical discography: clinical implications from 12 years of experience. Spine. 2000;25:1382–9. Slipman CW, Plastaras C, Patel R, Isaac Z, Chow D, Garvan C, Pauza K, Furman M. Provocative cervical discography symptom mapping. Spine J. 2005;5:381–8. Malmqvist EL, Bengtsson M, Sorenson J. Efficacy of stellate ganglion block: a clinical study with bupivacaine. Reg Anesth. 1992;17:340–7. Matsumoto S. Thermographic assessments of the sympathetic blockade by stellate ganglion (1): comparison between C7-SGB and C6-SGB in patients. Masui. 1991;40:562–9. Mastsumoto S. Thermographic assessment of the sympathetic blockade by stellate ganglion block (20): comparison between C7-SGB and C6-SGB in 20 healthy volunteers. Masui. 1991;40: 692–701. Wilkinson H. Percutaneous radiofrequency, upper thoracic sympathectomy. New technique. Neurosurgery. 1984;15:811–4. Wilkinson H. Neurosurgical procedures of the sympathetic nervous system. Pain Clin. 1995;1:43–50. Parent A. Autonomic nervous system. In: Carpenter’s human neuroanatomy. 9th ed. Media: Wiliams & Wilkins; 1996. p. 293–320. Standring S. Antomic nervous system. In: Gray’s anatomy. 40th ed. London: Churchill Livingstone; 2009. p. 232–6. McDonald JS, Pensak ML, Phero JC. Part II: thoughts on the management of chronic facial, head, and neck pain. Am J Oncol. 1990;11:378–82. Hogan QH, Abram SE. Neural blockade for diagnosis and prognosis: a review. Anesthesiology. 1997;86:216–41. Uchida K, Tateda T, Hino H. Novel mechanism of action hypothesized for stellate ganglion block related to melatonin. Med Hypotheses. 2002;59:446–9.
ORIGINAL ARTICLE
Interscalene brachial plexus block for scapular and upper chest pain due to cervical radiculopathy: a randomized controlled clinical trial Yasuaki Murata • Kohichi Kanaya • Hiroyoshi Wada • Keiji Wada • Masahiro Shiba Satoshi Hatta • Ken Kato • Yoshiharu Kato
•
Received: 4 February 2012 / Accepted: 15 May 2012 / Published online: 25 July 2012 Ó The Japanese Orthopaedic Association 2012
Abstract Background Animal experiments have shown that one of the pathways for pain originating from the cervical spine is the sympathetic trunk. However, there have been few reports regarding the cervical pain pathway and efficacy of interscalene brachial plexus block for upper limb, scapular and chest pain originating in the cervical spine in clinical cases. The purpose of the present study was to clarify the efficacy of interscalene brachial plexus block for upper limb, scapular and chest pain. Methods Patients (137 men and 223 women) who had cervical radicular pain were studied. The intensity of upper limb, scapular and chest pain was measured by using a VAS before injection and at 5 min and 7 days after injection. To evaluate the efficacy of interscalene brachial plexus block, patients with cervical radicular pain who had received NSAIDs for at least 2 weeks were randomized to interscalene brachial plexus block or control block groups. VAS scores were compared to assess the effects of injection and the pain pathway. Results The average VAS score for upper limb pain with or without scapular and chest pain was significantly reduced by interscalene brachial plexus block compared with control block at 5 min and 7 days after injection. After interscalene brachial plexus block, 89 patients reported symptoms of stellate ganglion block versus no patients after control block. Scapular and chest pain was
Y. Murata (&) K. Kanaya H. Wada K. Wada M. Shiba S. Hatta K. Kato Y. Kato Department of Orthopaedic Surgery, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjyuku-ku, Tokyo 162-8666, Japan e-mail: [email protected]
significantly reduced in the patients with stellate ganglion block compared to those without stellate ganglion block. Conclusions Interscalene brachial plexus block is useful for upper limb, scapular and chest pain due to disorders of the cervical spine. The scapular and chest pain pathway is more likely to be interrupted by an interscalene brachial plexus block that causes a stellate ganglion block compared to an interscalene brachial plexus block without stellate ganglion block.
Introduction Compression to the cervical spinal nerve can cause radicular pain in the upper limb. Cervical radiculopathy patients sometimes experience scapular and/or chest pain that is actually caused by disorders of the cervical spine and is thought to be referred from cervical structures [1]. Scapular pain mainly occurs in the T1 and/or T2 dermatomes, which are innervated by the dorsal rami of the T1 and/or T2 spinal nerves [2]. Chest pain that occurs in the area innervated by the T1 and/or T2 ventral rami is also occasionally accompanied by radicular pain [2]. Impulses from the cervical spinal nerves that are transmitted segmentally can cause upper limb pain and/or numbness, but these nerves do not innervate the scapula and chest on the dermatome. We hypothesized that the convergence-projection theory could be applied to scapular and chest pain. The theory is based on the anatomical finding that both visceral and somatic afferent fibers synapse with the same dorsal horn cells [3–7]. Interscalene brachial plexus block (IBPB) has been attempted clinically for the management of pain [8, 9]. However, there have been few reports regarding the efficacy and pain relief mechanisms of IBPB for upper limb,
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scapular and chest pain originating in the cervical spine in clinical cases. The purpose of this study was to clarify the efficacy of IBPB for cervical radicular pain, including upper limb, scapular and chest pain, considering the relation between the above-mentioned pain pathway and scapular and chest pain originating from the cervical spine.
Materials and methods To evaluate the efficacy of the IBPB, 360 patients (137 men and 223 women) who had cervical radicular pain were randomized to an IBPB group (n = 180) and a control block group (n = 180). A total of 20 patients dropped out of the study. All of the subjects had been treated with non-steroidal anti-inflammatory drugs (NSAIDs) for at least 2 weeks before enrollment and agreed to undergo the present prospective study. Demographic data were collected, including the age, gender, past medical history, location of pain and visual analog scale (VAS) severity of pain. There were no statistically significant differences between the IBPB and control group regarding these demographic data. The inclusion criteria for the study were patients with cervical radicular pain that had been treated with NSAIDs for at least 2 weeks, and who still had intolerable radicular pain with or without scapular and/or chest pain. When patients complained of ipsilateral upper limb pain along with a segmental region, we suspected radicular pain and diagnosed the pain according to the following procedure. The existence of pain region was diagrammed by interview. Physical examinations, including Spurling’s test, Jackson’s test, manual muscle testing, deep tendon reflex and pin prick test, were performed to identify the disturbed spinal nerve root. When Spurling’s test and/or Jackson’s test provoked segmental pain (positive sign), as a rule MRI was performed to confirm the nerve compression due to degenerative changes. CT was performed to clarify nerve compression due to degenerative change, including bony spars, instead of MRI for patients who were unable to undergo MRI. When the nerve was compressed by or in contact with degenerative tissue on axial images, the MRI or CT examination was considered positive. When the neurological findings were consistent with image results, patients were diagnosed as having radiculopathy. The exclusion criteria were previous spinal surgery, fresh spinal fracture, metastasis of malignant tumor and infections. Myelopathy patients were also excluded in the present study. Although more than half of the patients received non-operative treatment, such as injections and/or medications, after the study period, none of the patients received any additional injections during the study period. After a diagnosis of cervical spine radiculopathy was made, the patients were randomly assigned by one of the authors to either the IBPB group or the control block group
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by using sealed cards. All procedures were approved by the local ethics committee. Patients underwent either IBPB or control block. IBPB was performed by the same medical doctor as described by Winnie [10]. With the patient in the supine position, the posterior edge of the sternocleidomastoid muscle, the scalene hiatus and cricoid cartilage were confirmed to determine the injection point. The head was turned to the opposite side of the application; then a horizontal line was drawn from the cricoid cartilage to the interscalene groove. At the intersection of this line with the posterior edge of the sternocleidomastoid muscle, a 23-G needle was inserted and advanced in the caudal, medial and posterior directions to elicit upper limb muscle contraction and to provoke pain in the upper limb on the ipsilateral side. After contraction and pain had been evoked, a mixture of 7 ml of 1 % lidocaine and 3.3 mg of dexamethasone sodium phosphate was injected. For control block, a 23-G needle was inserted into the trapezius muscle on the ipsilateral side to a depth of 1.5 cm from the skin, and a mixture of 7 ml of 1 % lidocaine and 3.3 mg of dexamethasone sodium phosphate was injected. The intensity of radicular pain with/without scapular and chest pain was measured using the VAS before injection and at 5 min and 7 days after injection. VAS scores were measured by co-medical staff. The time for which the patient experienced no pain or pain that was tolerable without NSAIDs, i.e., the duration of an adequate therapeutic effect, was also determined. When patients showed ptosis 5 min after injection, we defined it as stellate ganglion block (SGB) effect. Statistical methods Visual analog scale scores were compared for patients in the IBPB and control group, and in the IBPB with and without SGB groups before injection and 5 min and 7 days after injection. Between-group differences were analyzed using analysis of variance (ANOVA). A p value less than 0.05 was considered statistically significant.
Results In total, 360 patients were diagnosed as cervical radiculopathy. There was no statistically significant difference between men and women with regard to the previous VAS (83 ± 24 mm for men and 82 ± 26 mm for women). The mean age of the subjects was 55 ± 13 years (range 39–90 years) in the IBPB group and 57 ± 15 years (43–93 years) in the control block group. The mean age of the men and women was 54 ± 9 and 55 ± 14 years, respectively. The average period that the patients had suffered from
Interscalene brachial plexus block
Fig. 1 Mean VAS (±SD) scores before injection and at 5 min and 7 days after injection. The mean VAS scores at 5 min (p \ 0.0001) and 7 days (p \ 0.0001) after injection were significantly lower in the IBPB group than in the control block group. There was no significant difference between the two groups before injection
radicular pain was 15 ± 17 months in the IBPB group and 14 ± 18 months in the control block group. There were no statistically significant differences in these variables between the two groups. The average VAS scores before injection and at 5 min and 7 days after injection are shown in Fig. 1. The average values at 5 min (p \ 0.0001) and 7 days (p \ 0.0001) after injection were significantly lower in the IBPB group than in the control block group. No statistically significant difference was observed between the two groups with regard to the VAS scores before injection. In the IBPB group, 80 patients reported an adequate therapeutic effect at 1 month after injection, and 9 of these patients reported that the effect persisted for more than 3 months (Fig. 2). In the control block group, 23 patients reported an adequate therapeutic effect after 1 month, and 7 of these patients reported that the effect persisted for more than 3 months (Fig. 2). Although a significantly larger number of patients reported a therapeutic effect of IBPB at 1 month, the difference was not statistically significant at 3 months. The average duration of an adequate effect in the IBPB and control block groups was 1.4 ± 2.4 and 0.9 ± 2.4 months, respectively, and the difference was statistically significant (p \ 0.05, Fig. 3). There were no statistically significant differences in pain scores between men and women. A total of 89 patients in the IBPB group versus no patients in the control block group showed the side effect of SGB. The average duration of an adequate effect of IBPB with and without SGB was 2.0 ± 3.1 and 0.7 ± 0.8 months, respectively, and the difference between these subgroups was statistically significant (p \ 0.001,
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Fig. 2 Number of patients with no pain or pain that was tolerable without NSAIDs. A significantly larger number of patients reported a therapeutic effect of IBPB at 1 month, but the difference was no longer significant at 3 months
Fig. 3 The average time (±SD) for which patients had no pain or pain that was tolerable without NSAIDs. The difference between the IBPB and control block groups was statistically significant (p \ 0.05). The difference between IBPB with and without SGB was also statistically significant (p \ 0.001)
Fig. 3). There were no statistically significant differences between IBPB with and without SGB regarding the age, gender, past medical history and location of pain. The average VAS scores before injection and at 5 min and 7 days after the injection are shown in Fig. 4. The average scores at 5 min (p \ 0.05) and 7 days (p \ 0.05) after injection were significantly lower for the IBPB patients with SGB than for those without SGB. No statistically significant difference was observed between these subgroups with regard to the VAS scores before injection. A total of 82 patients had scapular or chest pain (57 to the scapular region and 25 to the chest) in the IBPB group. With regard to this referred pain, the average VAS scores before injection and at 5 min and 7 days after injection are shown in Fig. 5. The average score at 5 min after injection
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to chest pain, the average VAS scores before injection and at 5 min and 7 days after injection were 66, 8 and 36, respectively, when IBPB was accompanied with SGB, and 69, 10 and 47 when IBPB was not accompanied with SGB. Trachyphonia, palpitations, constipation, hematoma and nausea occurred in six patients as side effects. One patient suffered from pneumothorax caused by the needle, and was hospitalized for 2 weeks to receive treatment. No infection developed throughout the observation period.
Discussion
Fig. 4 Mean VAS (±SD) scores before injection and at 5 min and 7 days after injection for the IBPB patients with SGB and without SGB. The mean scores at 5 min (p \ 0.05) and 7 days (p \ 0.05) after injection were significantly lower for the IBPB patients with SGB than for those without SGB. No statistically significant difference was observed between these two subgroups before injection
Fig. 5 Mean VAS (±SD) scores before injection and at 5 min and 7 days after injection for the patients who had pain in the scapular region and/or upper chest and received IBPB with or without SGB. The mean scores 5 min after injection were significantly lower in the patients who had IBPB with SGB than in those without SGB (p \ 0.05). There was no statistically significant difference between these subgroups before injection
was significantly lower in the case of IBPB with SGB than for IBPB without SGB (p \ 0.05). There was no statistically significant difference in the VAS score before injection between the two subgroups. As for scapular pain, the average VAS scores before injection and at 5 min and 7 days after injection were 85, 18 and 51, respectively, when IBPB was accompanied with SGB, and 84 28, and 53 when IBPB was not accompanied with SGB. With regard
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In this study, a total of 89 patients in the IBPB group showed symptoms of SGB. In patients who had scapular or chest pain, the average VAS scores at 5 min after injection were significantly lower when IBPB was associated with SGB than when IBPB was not associated with SGB. Namely, the scapular and chest pain pathway was more likely to be blocked by IBPB associated with SGB. As has been shown by previous animal experiments, it can be presumed that the afferent pathways for referred pain originating from cervical spinal nerves involve the sympathetic trunk via sympathetic afferents in humans, too [11]. Interscalene brachial plexus block is used in upper limb surgery for anesthesia and postoperative analgesia. Neural complications and pneumothorax are a major concern of anesthetists performing IBPB. According to Winnie [10], the block needle direction is perpendicular to all planes at the entry point of the skin. Modifications of IBPB techniques are described in the literature. Some authors encourage a more caudad needle angulation to minimize potential entry into the spinal canal. According to the previous reports, the success of IBPB is owing to the dose of anesthetic [12, 13]. Most commonly 20–40 ml of anesthetic is used to provide a sufficient block of the brachial plexus. It has been reported that the 40 ml injected solution extends a greater distance up and down the sheath than the 20 ml injection by taking X-rays after the injection of anesthetic with contrast medium [10]. However, a very low volume of local anesthetic seems to provide a more selective block of the upper cervical plexus without complete anesthesia of the lower part derived from the C8/Th1 roots [12]. In the present study, a total of 8 ml of anesthetic was used for IBPB. Although we could not present the information about the spread of anesthetic, most likely the plexus was not completely anaesthetized in all patients considering the low volume used in the study. It has been reported that scapular and chest pain can be caused by disorders of the cervical spine and referred from cervical structures [1, 14–18]. Such referred pain is distributed to the dermatome of the dorsal rami of the cervical spinal nerves and to the T1 and T2 dermatomes. The
Interscalene brachial plexus block
suprascapular nerve arises from the C4, C5 and C6 spinal nerves to innervate the supraspinous and infraspinous fossae of the scapular, and is sometimes blocked clinically for the treatment of neck and shoulder pain. However, some referred pain manifests below cervical dermatomes. Such referred pain does not occur in the territory of the cervical spinal nerves, but in the T1 and/or T2 dermatomes. Some clinicians have reported that SGB at the injection level of the C6 vertebra produced successful effects for headache and neck pain and less success for the upper limbs. On the contrary, SGB at the injection level of the C7 vertebra showed successful effects for the upper limbs [19– 21]. SGB at the injection level of T2 was more successful for the upper limbs, including the scapula [22, 23]. These facts may be related to the anatomical structure of the white rami communicantes. The efferent pathway from the cervical spinal nerves to the sympathetic trunk is provided by the gray rami communicantes (Fig. 6a) [24, 25]. However, there are no white rami communicantes to act as the afferent pathway from the sympathetic trunk to the cervical spinal nerves. The white rami communicantes are only connected to the spinal nerves from T1 to L2. It is reasonable to consider that pain signals originating from the cervical spine that enter the sympathetic trunk reach the spinal cord via the shortest pathways, so the white rami communicantes of T1 would be the likely pathway (Fig. 6b).
Fig. 6 Efferent pathway from the spinal nerves to the sympathetic trunk, and afferent pathway from the sympathetic trunk to the spinal nerves. a The gray rami communicantes from cervical to sacral levels provide an efferent pathway. The afferent pathway is provided by the white rami communicantes, which only exist from T1 to L2. ST sympathetic trunk, R ramus communicans, SN spinal nerve. b Pain signals from the cervical spine can be transmitted to the sympathetic trunk via the gray rami communicantes. The shortest pathway for these signals to reach the spinal cord is via the white rami communicantes of T1
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One of the blockades of sympathetic efferent nerve fibers, SGB, has been used clinically for the management of painful conditions such as cephalic, facial and upper limb pain caused by insufficient blood supply to the upper limbs, frostbite, acute vessel spasms, complex regional pain syndrome, hemicrania and trigeminal neuralgia [26]. The stellate ganglion consists of the T1 and inferior cervical sympathetic ganglia. It is usually located in front of the C7 vertebra between the longus coli muscle and the anterior scalene muscle. SGB is performed using local anesthetic, opioids and/or steroids. This procedure can be performed blindly or under fluoroscopic guidance at the anterior tubercle of the C6 vertebra. Complications of SGB include complications related to the technique, infection and pharmacological complications related to the drugs utilized. The mechanism of SGB effects has generally been explained by increased blood flow as a result of peripheral vasodilation, resulting in neural inhibition of the sphere innervated by sympathetic efferent nerve fibers. However, the wide ranges of conditions that respond to SGB suggest that its effectiveness may not be solely the result of increased blood flow. It has been suggested that the effects may be due to influences on sensory mechanisms and sympathetic efferent impulses depolarizing nociceptive afferent fibers [27]. Uchida et al. [28] theorized that melatonin-related dysrhythmias are the result of chronically increased sympathetic nerve tone, which eventually causes decreased functioning of pinealocytes and leads to reduction of plasma melatonin levels. According to their reports, SGB may interrupt the sympathetic cycle, allowing the normal melatonin rhythm to be re-established. The underlying mechanism of pain relief seen in SGB is not totally understood. We acknowledge that our results are limited by incomplete blinding. The clinicians knew who had received IBPB because the subjects were clinical patients. However, as the patients did not know the exact character of the injection during the observation periods, pain relief seemed to be responded to blindly. Although the same amount of saline injection to the interscalene brachial plexus may be the best way to blind patients, this injection creates ethical problems for clinical cases. Thus, we injected the same anesthetic solution to the trapezius muscle, which is near the IBPB injection point. From the present results, it can be concluded that IBPB is useful for reducing radicular pain, including scapular and chest pain, due to disorders of the cervical spine, and the scapular and chest pain pathway is more likely to be interrupted by IBPB associated with SGB than by IBPB without SGB. Some afferent fibers of the pathway for cervical pain may run in the T1 and/or T2 spinal nerves, to which impulse are presumably transmitted via sympathetic afferents.
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Y. Murata et al. The authors declare that they have no conflict 14.
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