An unusual complication of interscalene brachial plexus catheterization: delayed catheter migration
C. R. Jenkins* and
M. K. Karmakar
Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong
* Corresponding author. E-mail: carolinejenkins{at}cuhk.edu.hk
Accepted for publication July 4, 2005.
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Abstract
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This case report describes the delayed migration of an interscalene brachial plexus catheter that was inserted for postoperative analgesia and to facilitate physiotherapy after shoulder surgery. Approximately 18 h after surgery the catheter was found to have migrated into the interpleural space, which could have resulted in a serious complication, namely a pneumothorax.
Keywords:
anaesthetic techniques, regional, brachial plexus
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analgesia
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complications, interscalene catheter migration
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Introduction
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Continuous interscalene brachial plexus block is commonly used in patients undergoing shoulder surgery because it provides effective perioperative analgesia1 and also facilitates physiotherapy after surgery.2 It is common practice at our hospital to place an interscalene catheter in patients undergoing shoulder surgery and to administer twice daily top up injections of local anaesthetic via the catheter before each physiotherapy session during the postoperative period. Complications following the use of an interscalene catheter are relatively uncommon.3 In this report we describe an unusual, but potentially serious complication, that occurred in the postoperative period.
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Case report
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A 32-yr-old (ASA physical status I, body weight 85 kg) man who suffered from post-traumatic shoulder stiffness was to undergo manipulation under anaesthesia, a shoulder arthroscopy, and postoperative physiotherapy. Before general anaesthesia, a right-sided interscalene catheter was inserted under strict aseptic precautions and via a classical Winnie's approach.4 A Contiplex D end hole catheter set (Contiplex D; B Braun, USA) with a nerve stimulator was used. The brachial plexus was identified at a depth of approximately 2 cm from the skin by observing contractions of the ipsilateral triceps muscle. The needle position was optimized until muscular twitches were still just visible in the triceps at a threshold current of 0.5 mA. The Contiplex sheath was then advanced over the stimulating needle into the brachial plexus sheath after which the needle was removed. A catheter was then passed through the sheath and advanced easily to a depth of 8 cm at the skin (i.e. 6 cm in the space). The sheath was then removed and the catheter was fixed to the skin with a sterile, transparent dressing. After negative aspiration of the catheter, 20 ml of bupivacaine 0.25% was injected in aliquots of 35 ml over 23 min. The patient reported neither pain nor paraesthesia during injection of local anaesthetic. General anaesthesia was then induced with i.v. fentanyl (50 µg) and propofol (140 mg). Atracurium (40 mg) was administered to facilitate tracheal intubation (size 8.0 oral cuffed tracheal tube). Anaesthesia was maintained with a mixture of nitrous oxide and oxygen (30%) supplemented with isoflurane (0.81.0%). The surgery was uneventful and the procedure lasted for approximately 90 min. At the end of surgery, neuromuscular block was reversed using neostigmine 50 µg kg1 and atropine 20 µg kg1, and the patient was extubated when awake. In the recovery room it was noted that he had residual anaesthesia over the shoulder and also complained of some nasal congestion. He did not exhibit ptosis. Additional analgesia was not required before transfer to the ward.
The following morning (09.00), the patient was reviewed by our acute pain team and 15 ml of lignocaine 1% was injected in aliquots over 23 min via the indwelling catheter, with the patient in a semi-recumbent (approximately 30°) position in bed. Shoulder analgesia was adequate for the physiotherapy, which was performed 30 min after the local anaesthetic injection. When questioned, he reported mild pain with a verbal analogue pain score of 2/10 (0=no pain, 10=worst imaginable pain). At 15.00 the patient was reviewed again before physiotherapy. As he had complained of mild discomfort during the morning session it was decided to increase the dose of lignocaine 1% to 20 ml. Within 1520 min of the second injection he began to complain of mild ipsilateral chest wall numbness. Sensation to cold (ice) over the shoulder and arm was unimpaired. There was loss of chest wall sensation from the T2T6 dermatome and a possible interpleural block was suspected.
To confirm our suspicion and locate the position of the catheter tip, pre- and post-contrast CT scans of the neck and upper thorax were arranged. 5 ml of Iopamiro-300 (Iopamidol, Bracco, Milano, Italy, 300 mg ml1 iodine) was injected via the indwelling catheter immediately before the post-contrast CT scan. The post-contrast CT scans demonstrated the catheter in the space between the scalenus medius, scalenus anterior, and longus colli muscles (Fig. 1) and the tip of the catheter situated in the apical region of the pleural cavity (Fig. 2). Contrast medium was scattered over the upper pleural space (Fig. 3). There was no evidence of a pneumothorax.

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Fig 1 Cross sectional CT scan image at C7 after contrast injection through the catheter. (1) Scalenus medius muscle; (2) scalenus anterior muscle; and (3) longus colli muscle.
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Fig 2 Two-dimensional reconstruction of the CT scan which shows that the catheter tip (1) is located in the pleural cavity.
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Fig 3 Cross-sectional CT scan image at the level of T1 after contrast injection through the catheter. The scattering of contrast medium (as denoted by the arrows) can be seen. (1) Right upper pleural space.
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The catheter was removed and the patient was closely monitored for signs of a pneumothorax. There were no further complications and the patient was discharged home 2 days later.
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Discussion
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This case report describes a case of interpleural migration of an interscalene brachial plexus catheter. Complications following interscalene catheterization are rare.3 Those arising from interscalene block include brachial plexus injury, idiopathic brachial plexitis, unintended spinal and epidural anaesthesia, pneumothorax, central nervous system intoxication, and inadvertent intravascular placement.3 Interpleural migration of an interscalene catheter has been described previously by Souron and colleagues.5 They injected (30 ml of ropivacaine 0.75%) through the needle that was used to locate the brachial plexus before advancing a catheter 8 cm beyond the needle tip. The resultant brachial plexus block, in conjunction with sedation (propofol), was effective for surgical anaesthesia (arthroscopic shoulder surgery).5 The interpleural location of the catheter was identified in the routine post-contrast radiograph of the shoulder and neck region in the recovery room.5 Therefore, we believe the catheter had inadvertently entered the interpleural space during the insertion process rather than migrated postoperatively as in our case.
No formal sensory motor assessment for brachial plexus block was performed in our patient but no supplementary analgesia was required during the perioperative period. There was also residual brachial plexus block with generalized weakness of the upper limb when the patient was first assessed in the recovery room. The first top up injection of local anaesthetic via the indwelling catheter also provided effective analgesia for physiotherapy. These facts suggest correct initial placement of the catheter. It was only after the second top up injection of local anaesthetic that a problem was detected, suggesting that the catheter had migrated. The CT scan confirmed that the catheter had migrated through the dome of the pleura into the interpleural space. As interpleural block is gravity dependent and our patient was nursed in the upright position, it is of interest that the sensory block was confined to the upper thoracic dermatomes.
A review of the literature reveals only the report of Souron and his colleagues5 in relation to trans-compartmental migration of plexus block catheters. In our case, we believe that the length of catheter inserted into the plexus sheath and the postoperative active physiotherapy that our patient received may have contributed to the migration. The optimal length of catheter that should be left in-situ during interscalene catheterization is not known. Leaving too short a length of catheter within the brachial plexus sheath may result in catheter dislodgement. Souron and colleagues5 report that when an average length of 3 cm of catheter is left in-situ the post-contrast radiographs always demonstrate correct position of the catheter and distribution of contrast.5 Therefore, in clinical practice 34 cm of catheter should be inserted into the brachial plexus sheath.
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References
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1 Borgeat A, Ekatodramis G. Anaesthesia for shoulder surgery. Clin Anaesthesiol 2002; 16: 21125
2 Borgeat A, Schappi B, Biasca N, Gerber C. Patient-controlled analgesia after major shoulder surgery. Anesthesiology 2003; 87: 13437
3 Borgeat A, Ekatodramis G, Kalberer F, Benz C. Acute and nonacute complications associated with interscalene block and shoulder surgery; a prospective study. Anesthesiology 2001; 95: 87580[CrossRef][ISI][Medline]
4 Winnie A. Interscalene brachial plexus block. Anesth Analg 1970; 49: 45566[Medline]
5 Souron V, Reiland Y, De Traverse A, Delauney L, Lafosse L. Interpleural migration of an interscalene catheter. Letter to the editor. Anaesth Analg 2003; 97: 12001[Free Full Text]