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Epidural Spread After Continuous Cervical Paravertebral Block: A Case Report
Epidural Spread After Continuous Cervical Paravertebral Block: A Case Report Robert M. Frohm, M.D., Robert M. Raw, M.B.Ch.B., F.C.A.(S.A.), Naeem Haider, M.D., and André P. Boezaart, M.B.Ch.B., F.F.A.(C.M.S.A.), M.Med.(Anesth.), Ph.D. Background and Objective: This report illustrates epidural spread after continuous cervical paravertebral block (CCPVB). By fluoroscopy, it also explains the mechanism of the complication. Case Report: A healthy 22-year-old male developed bilateral upper-extremity motor weakness immediately after placement of a continuous cervical paravertebral block for postoperative pain control after shoulder stabilization surgery. The tip of the stimulating catheter was demonstrated in the C7 neuroforamen. Contrast injected through the catheter demonstrated epidural spread. The contralateral block resolved after 4 hours and the patient suffered no respiratory embarrassment or other untoward sequelae. Conclusion: Continuous cervical paravertebral block is a relatively new, but generally well-accepted, modality for postoperative pain control after major surgery to the upper limb. Epidural spread is recognized as a complication. In this particular case, medial placement of the catheter was possibly caused by unintentional medial direction of the bevel of the Tuohy needle. Meticulous attention to the direction of the needle bevel and early recognition and management of adverse events are mandatory. The same principles may apply for continuous thoracic, lumbar, and sacral paravertebral blocks. Reg Anesth Pain Med 2006;31:279-281. Key Words: Continuous cervical paravertebral block, Paravertebral block, Complications, Regional anesthesia, Epidural spread, Epidural catheter.
C
ontinuous cervical paravertebral block (CCPVB) is a promising modality for major shoulder procedures.1 This block is indicated for painful conditions of the upper extremity, particularly major joint surgery of the shoulder, wrist, and elbow. Known complications from this block include Horner’s syndrome, dyspnea, superficial skin infections, posterior neck pain, subclavian artery puncture, and contralateral epidural spread.1 In this case report, we outline the events surrounding contralateral epidural spread and propose a likely mechanism of action.
Case Report An otherwise healthy 22-year-old man presented for right-sided arthroscopic shoulder stabilization
From the Regional Anesthesia Study Center of Iowa, Department of Anesthesia, University of Iowa, Iowa City, IA. Accepted for publication February 1, 2006. Reprint requests: André P Boezaart, M.B.Ch.B., F.F.A. (C.M.S.A.), Department of Anesthesia, University of Iowa, 200 Hawkins Drive, 6-JCP, Iowa City, IA, 52242. E-mail: [email protected] © 2006 by the American Society of Regional Anesthesia and Pain Medicine. 1098-7339/06/3103-0017$32.00/0 doi:10.1016/j.rapm.2005.02.010
surgery. Anesthesia included preoperative CCPVB for intraoperative and postoperative analgesia plus general anesthesia for the procedure. For CCPVB placement, the patient was placed in the lateral decubitus position and monitoring was per ASA protocol. Two milligrams of intravenous midazolam and 1,000 g of alfentanil were administered for sedation, with supplemental oxygen via nasal cannula. As previously described,2 the lateral border of the trapezius muscle and the medial border of the levator scapulae were identified. The point of needle entry was on a line drawn between the spinous process of the 6th cervical vertebrae (C6) and the suprasternal notch, anterolateral to the trapezius muscle and posteromedial to the levator scapulae muscle in the apex of the V formed by these two muscles approximately 3-5 cm from the midline posterior. The needle entry point and the area of intended tunneling for the catheter were anesthetized with 10 mL of 1% lidocaine. An insulated 17-gauge Tuohy needle (StimuCath; Arrow International, Reading, PA) was attached to a peripheral nerve stimulator with the current set to 1 mA, the pulse width at 300 s, and a frequency of 2 Hz. The needle was directed anteriorly and caudally, and toward the suprasternal notch until con-
Regional Anesthesia and Pain Medicine, Vol 31, No 3 (May–June), 2006: pp 279 –281
279
280
Regional Anesthesia and Pain Medicine Vol. 31 No. 3 May–June 2006
tact with the pars intervertebralis or articular column of C6 was made. The needle stylette was removed, and a loss of resistance to air syringe was attached to the needle. The needle was then “walked off” the bony structure laterally, and, upon slight advancement of the needle (approximately 1 cm), loss of resistance to air was noted, followed immediately by a motor response, mainly of the triceps muscle. The catheter was then tunneled subcutaneously in a medial direction. A test solution of 2 mL of normal saline with 1:400,000 epinephrine, after negative aspiration, produced immediate loss of the twitch with no indication of intravascular injection. Postprocedure vital signs were unchanged from preprocedure vital signs. Ropivacaine (0.75%) was injected incrementally to a total dose of 30 mL via the catheter, and the patient was transported to the operating room. Approximately 5 minutes after completion of the injection, the patient reported that he was experiencing a feeling of “numbness” in both hands. Motor block was noted in the proximal muscles of the operative side at that time. General anesthesia was induced. A laryngeal mask airway was placed, mechanical ventilation was provided, and general anesthesia was maintained with sevoflurane in an air and oxygen mixture. The patient’s lungs were mechanically ventilated throughout the surgery, which lasted 105 minutes. No further local anesthetic boluses were administered via the catheter and no further narcotic was required. Emergence from general anesthesia proceeded uneventfully. Initial neurologic examination revealed that the patient had no motor or sensory function in the right upper extremity. The left extremity demonstrated minimal biceps function with greatly diminished sensory function in the extremity. No symptoms or signs of respiratory depression were seen. A series of fluoroscopic studies with contrast revealed that the catheter was lying with its tip at the neuroforamen of the 7th cervical vertebra (C7) (Fig 1). Three milliliters of contrast medium were injected, which demonstrated epidural spread from the 5th cervical (C4) to the 4th thoracic (T4) vertebra. This spread increased with a further injection of 2 mL of normal saline (Fig 1). With further neurologic evaluation 15 minutes later, the patient had intact motor function in the left extremity (the contralateral side), but continued to have decreased sensation in that arm. Examination of the right side (the operative side) revealed continued loss of motor function and the absence of sensation accompanied by good analgesia. Additionally, he reported a feeling of numbness over the area of his chest (approximately T3-4 dermatome) from the midster-
Fig 1. Oblique fluoroscopic view of the neck that shows the tip of the catheter in the vicinity of the C7 neuroforamen. Also shown is the spread of contrast medium in the epidural space from C5 to T4.
num area to the root of the neck. The catheter was removed without evidence of breakage, and the patient had an uneventful postoperative course. Neurologic function was intact at 2-week follow-up.
Discussion Large volumes of solution within the interscalene space have previously demonstrated spread from the transverse processes of the upper cervical vertebrae to the coracoid process and beyond.3,4 Further cephalad spread could theoretically result in epidural spread; however, the incidence of contralateral epidural spread with cervical paravertebral blocks was noted to be 4% with bolus doses of 30 mL.1 When we perform CCPVB, we can easily envision that a catheter will follow the path of the brachial plexus as it is threaded. In this case, we had no difficulties in identifying the brachial plexus when utilizing the Tuohy needle or the stimulating catheter. Throughout the procedure, triceps motor responses were maintained as the catheter was inserted to its final position. Despite appearing technically unremarkable, the tip of the catheter approached a neuroforamen. In retrospect, we hypothesize that the bevel of the Tuohy needle probably pointed medially. When CCPVB is performed, tracking the direction of the needle bevel seems essential, particularly at the time of catheter insertion. Furthermore, a triceps motor response (C7) is probably not
Epidural Spread after CCPVB
appropriate for shoulder surgery, because the small infusion volumes used for continuous block will probably not reach the essential C5 and C6 roots. It might, however, be appropriate for elbow and wrist surgery. In contrast to what was previously believed,2 we speculate that the needle and catheter should be directed toward the C5 and C6 roots of superior trunk for shoulder surgery and toward the C7, C8, and T1 roots or inferior trunk for wrist and elbow surgery. This notion, however, requires further research. With the catheter tip lying in the C7 neuroforamen (Fig 1), even small volumes of injectate can result in epidural spread. Epidural spread is a recognized complication of perineuraxial blocks. Lumbar and thoracic paravertebral somatic nerve blocks, by use of 5 mL of contrast demonstrated epidural spread in up to 70% of cases in one series.5 Lumbar paravertebral blocks were noted to have an epidural spread in 1.3%.6 The CCPVB has a 4% incidence of epidural spread. Inconsistency seems to exist between the degree of epidural block produced with 30 mL of local anesthetic agent and the 5 mL of contrast medium. One explanation for this inconsistency may be that injection of large volumes may have produced backflow to the paravertebral space as well as vertical epidural spread. Given the patient’s postprocedure examination, this supposition does seem valid. Because the patient received general anesthesia after the injection of local anesthetic agent, neurologic testing could not be performed
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Frohm et al.
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until the conclusion of the case. The degree of epidural block may have been more significant during this period. Although other reasons for epidural spread may be postulated, the placement of the catheter in the neuroforamen explains the spread in this case. When CCPVB is performed, tracking the direction of the needle bevel may be essential, particularly at the time of catheter insertion, to avoid placing the catheter tip near or within the neuroforamen.6
References 1. Boezaart AP, De Beer JF, Nell ML. Early experience with continuous cervical paravertebral block using a stimulating catheter. Reg Anesth Pain Med 2003;28: 406-413. 2. Boezaart AP, Koom R, Rosenquist RW. Paravertebral approach to the brachial plexus: An anatomic improvement in technique. Reg Anesth Pain Med 2003; 28:241-244. 3. Winnie AP. Interscalene brachial plexus block. Anesth Analg 1970;49:455-466. 4. Winnie AP, Collins VJ. The subclavian perivascular technique of brachial plexus anesthesia. Anesthesiology 1964;25:353-363. 5. Purcell-Jones G, Pither CE, Justins DM. Paravertebral somatic nerve block: A clinical, radiographic, and computed tomographic study in chronic pain patients. Anesth Analg 1989;68:32-39. 6. Naja Z, Lonnqvist PA. Somatic paravertebral nerve blockade incidence of failed block and complications. Anaesthesia 2001;56:1184.
C
ontinuous cervical paravertebral block (CCPVB) is a promising modality for major shoulder procedures.1 This block is indicated for painful conditions of the upper extremity, particularly major joint surgery of the shoulder, wrist, and elbow. Known complications from this block include Horner’s syndrome, dyspnea, superficial skin infections, posterior neck pain, subclavian artery puncture, and contralateral epidural spread.1 In this case report, we outline the events surrounding contralateral epidural spread and propose a likely mechanism of action.
Case Report An otherwise healthy 22-year-old man presented for right-sided arthroscopic shoulder stabilization
From the Regional Anesthesia Study Center of Iowa, Department of Anesthesia, University of Iowa, Iowa City, IA. Accepted for publication February 1, 2006. Reprint requests: André P Boezaart, M.B.Ch.B., F.F.A. (C.M.S.A.), Department of Anesthesia, University of Iowa, 200 Hawkins Drive, 6-JCP, Iowa City, IA, 52242. E-mail: [email protected] © 2006 by the American Society of Regional Anesthesia and Pain Medicine. 1098-7339/06/3103-0017$32.00/0 doi:10.1016/j.rapm.2005.02.010
surgery. Anesthesia included preoperative CCPVB for intraoperative and postoperative analgesia plus general anesthesia for the procedure. For CCPVB placement, the patient was placed in the lateral decubitus position and monitoring was per ASA protocol. Two milligrams of intravenous midazolam and 1,000 g of alfentanil were administered for sedation, with supplemental oxygen via nasal cannula. As previously described,2 the lateral border of the trapezius muscle and the medial border of the levator scapulae were identified. The point of needle entry was on a line drawn between the spinous process of the 6th cervical vertebrae (C6) and the suprasternal notch, anterolateral to the trapezius muscle and posteromedial to the levator scapulae muscle in the apex of the V formed by these two muscles approximately 3-5 cm from the midline posterior. The needle entry point and the area of intended tunneling for the catheter were anesthetized with 10 mL of 1% lidocaine. An insulated 17-gauge Tuohy needle (StimuCath; Arrow International, Reading, PA) was attached to a peripheral nerve stimulator with the current set to 1 mA, the pulse width at 300 s, and a frequency of 2 Hz. The needle was directed anteriorly and caudally, and toward the suprasternal notch until con-
Regional Anesthesia and Pain Medicine, Vol 31, No 3 (May–June), 2006: pp 279 –281
279
280
Regional Anesthesia and Pain Medicine Vol. 31 No. 3 May–June 2006
tact with the pars intervertebralis or articular column of C6 was made. The needle stylette was removed, and a loss of resistance to air syringe was attached to the needle. The needle was then “walked off” the bony structure laterally, and, upon slight advancement of the needle (approximately 1 cm), loss of resistance to air was noted, followed immediately by a motor response, mainly of the triceps muscle. The catheter was then tunneled subcutaneously in a medial direction. A test solution of 2 mL of normal saline with 1:400,000 epinephrine, after negative aspiration, produced immediate loss of the twitch with no indication of intravascular injection. Postprocedure vital signs were unchanged from preprocedure vital signs. Ropivacaine (0.75%) was injected incrementally to a total dose of 30 mL via the catheter, and the patient was transported to the operating room. Approximately 5 minutes after completion of the injection, the patient reported that he was experiencing a feeling of “numbness” in both hands. Motor block was noted in the proximal muscles of the operative side at that time. General anesthesia was induced. A laryngeal mask airway was placed, mechanical ventilation was provided, and general anesthesia was maintained with sevoflurane in an air and oxygen mixture. The patient’s lungs were mechanically ventilated throughout the surgery, which lasted 105 minutes. No further local anesthetic boluses were administered via the catheter and no further narcotic was required. Emergence from general anesthesia proceeded uneventfully. Initial neurologic examination revealed that the patient had no motor or sensory function in the right upper extremity. The left extremity demonstrated minimal biceps function with greatly diminished sensory function in the extremity. No symptoms or signs of respiratory depression were seen. A series of fluoroscopic studies with contrast revealed that the catheter was lying with its tip at the neuroforamen of the 7th cervical vertebra (C7) (Fig 1). Three milliliters of contrast medium were injected, which demonstrated epidural spread from the 5th cervical (C4) to the 4th thoracic (T4) vertebra. This spread increased with a further injection of 2 mL of normal saline (Fig 1). With further neurologic evaluation 15 minutes later, the patient had intact motor function in the left extremity (the contralateral side), but continued to have decreased sensation in that arm. Examination of the right side (the operative side) revealed continued loss of motor function and the absence of sensation accompanied by good analgesia. Additionally, he reported a feeling of numbness over the area of his chest (approximately T3-4 dermatome) from the midster-
Fig 1. Oblique fluoroscopic view of the neck that shows the tip of the catheter in the vicinity of the C7 neuroforamen. Also shown is the spread of contrast medium in the epidural space from C5 to T4.
num area to the root of the neck. The catheter was removed without evidence of breakage, and the patient had an uneventful postoperative course. Neurologic function was intact at 2-week follow-up.
Discussion Large volumes of solution within the interscalene space have previously demonstrated spread from the transverse processes of the upper cervical vertebrae to the coracoid process and beyond.3,4 Further cephalad spread could theoretically result in epidural spread; however, the incidence of contralateral epidural spread with cervical paravertebral blocks was noted to be 4% with bolus doses of 30 mL.1 When we perform CCPVB, we can easily envision that a catheter will follow the path of the brachial plexus as it is threaded. In this case, we had no difficulties in identifying the brachial plexus when utilizing the Tuohy needle or the stimulating catheter. Throughout the procedure, triceps motor responses were maintained as the catheter was inserted to its final position. Despite appearing technically unremarkable, the tip of the catheter approached a neuroforamen. In retrospect, we hypothesize that the bevel of the Tuohy needle probably pointed medially. When CCPVB is performed, tracking the direction of the needle bevel seems essential, particularly at the time of catheter insertion. Furthermore, a triceps motor response (C7) is probably not
Epidural Spread after CCPVB
appropriate for shoulder surgery, because the small infusion volumes used for continuous block will probably not reach the essential C5 and C6 roots. It might, however, be appropriate for elbow and wrist surgery. In contrast to what was previously believed,2 we speculate that the needle and catheter should be directed toward the C5 and C6 roots of superior trunk for shoulder surgery and toward the C7, C8, and T1 roots or inferior trunk for wrist and elbow surgery. This notion, however, requires further research. With the catheter tip lying in the C7 neuroforamen (Fig 1), even small volumes of injectate can result in epidural spread. Epidural spread is a recognized complication of perineuraxial blocks. Lumbar and thoracic paravertebral somatic nerve blocks, by use of 5 mL of contrast demonstrated epidural spread in up to 70% of cases in one series.5 Lumbar paravertebral blocks were noted to have an epidural spread in 1.3%.6 The CCPVB has a 4% incidence of epidural spread. Inconsistency seems to exist between the degree of epidural block produced with 30 mL of local anesthetic agent and the 5 mL of contrast medium. One explanation for this inconsistency may be that injection of large volumes may have produced backflow to the paravertebral space as well as vertical epidural spread. Given the patient’s postprocedure examination, this supposition does seem valid. Because the patient received general anesthesia after the injection of local anesthetic agent, neurologic testing could not be performed
•
Frohm et al.
281
until the conclusion of the case. The degree of epidural block may have been more significant during this period. Although other reasons for epidural spread may be postulated, the placement of the catheter in the neuroforamen explains the spread in this case. When CCPVB is performed, tracking the direction of the needle bevel may be essential, particularly at the time of catheter insertion, to avoid placing the catheter tip near or within the neuroforamen.6
References 1. Boezaart AP, De Beer JF, Nell ML. Early experience with continuous cervical paravertebral block using a stimulating catheter. Reg Anesth Pain Med 2003;28: 406-413. 2. Boezaart AP, Koom R, Rosenquist RW. Paravertebral approach to the brachial plexus: An anatomic improvement in technique. Reg Anesth Pain Med 2003; 28:241-244. 3. Winnie AP. Interscalene brachial plexus block. Anesth Analg 1970;49:455-466. 4. Winnie AP, Collins VJ. The subclavian perivascular technique of brachial plexus anesthesia. Anesthesiology 1964;25:353-363. 5. Purcell-Jones G, Pither CE, Justins DM. Paravertebral somatic nerve block: A clinical, radiographic, and computed tomographic study in chronic pain patients. Anesth Analg 1989;68:32-39. 6. Naja Z, Lonnqvist PA. Somatic paravertebral nerve blockade incidence of failed block and complications. Anaesthesia 2001;56:1184.