Of the sixteen patients with a block failure, nine had an unsuccessful result because the interscalene regional block was not achieved and three had an incomplete block (see Appendix). In addition, two patients could not tolerate the block placement, and one patient could not tolerate the positioning and the length of the procedure and thus adjunctive general anesthesia was induced midway through the operation. In the remaining patient, local anesthetic tinged with blood was aspirated after injection of 20 mL of 1.5% mepivacaine. The patient exhibited no signs of central nervous system toxicity and had no signs of seizure activity during a five-minute period of observation, but the interscalene regional block was aborted and general anesthesia was induced.
Prior to the start of the surgical procedure, all 462 patients receiving interscalene regional block alone were given an additional field block averaging 7.7 mL of a mixture of 0.25% bupivacaine and 1% lidocaine with epinephrine. Of those patients, 397 received propofol at an average rate of 37.5 μg/kg/min and 455 received an average of 1.7 mg of midazolam. In addition, 319 of the 455 patients received an average of 44.5 μg of fentanyl during the procedure. For the sixty-nine patients managed with general anesthesia alone, the average dose of midazolam was 1.83 mg and the average dose of fentanyl was 360 μg.
For the patients who received interscalene regional block alone, the average procedure length was 157 minutes, the average anesthesia length was 211 minutes, and the average nonsurgical time was fifty-four minutes. For the patients managed with general anesthesia alone, the average procedure length was 174 minutes, the average anesthesia time was 255 minutes, and the average nonsurgical time was eighty-one minutes. This difference between nonsurgical times for interscalene regional block alone and general anesthesia alone was found to be significant (p < 0.02). With the numbers available, no difference was detected between procedure lengths when patients who had general anesthesia were compared with those who had an interscalene regional block (p = 0.09).
No patient had an acute complication; however, twelve (2.3%) of the 512 patients who received an interscalene regional block had a nonacute complication (Table I). All symptoms of the nonacute complications appeared within fourteen days after the surgical procedure and were reported by the patients at the two-week postoperative follow-up visit. Eight of the twelve complications occurred in patients who had open surgical procedures, whereas four developed in patients who had arthroscopy. Therefore, the complication rate was 1.4% for those receiving an interscalene regional block for arthroscopy and 3.2% for those who had open shoulder surgery. None of the patients had any clinical motor weakness. The most serious complication, complex regional pain syndrome, occurred in a patient who underwent a total shoulder arthroplasty to treat a chronic anterior shoulder dislocation. Exploration of the brachial plexus and isolation of the axillary nerve was required. In eleven patients, the symptoms spontaneously resolved by an average of nine weeks (range, two weeks to six months). Only one patient did not have complete resolution of the paresthesias in the ring and little fingers. The symptoms were mild enough that the patient did not want any additional investigation or treatment. One patient had transient facial numbness, which was thought to be due to the positioning of the face mask used to secure the head during the operation. There were no complications of general anesthesia.
This study confirms the finding that interscalene regional block is an effective anesthetic technique for both arthroscopic and open surgical procedures of the shoulder. The rate of successful blocks was 97%, the rate of short-term complications was 2.3%, and no patient had permanent disabling neurologic sequelae or seizures. Thus, we think that the advantages of interscalene regional block far outweigh the disadvantages of the technique. We believe that the ability to have a successful regional anesthesia program requires commitment and depends upon cooperation between the surgeons and the anesthesiologists. We introduce our patients to the concept of the interscalene regional block at the office of the senior surgeon during the surgical scheduling visit, when the risks and benefits of the anesthetic options are discussed. If it is presented as an advantageous method that avoids airway manipulations and postoperative nausea and vomiting and offers postoperative analgesia, there is a high degree of patient acceptance. We explain that there will be light sedation during the block placement, which will continue, as the patient desires, intraoperatively. Our anesthesiology residents receive extensive training in interscalene regional block and are supervised by a cadre of attending anesthesiologists who are committed to the use of regional anesthesia. Surgeons, too, must understand the anatomic limitations of the block and the necessity to supplement blocks, and they should not consider this cooperative effort to be a sign of block failure.
Our findings are consistent with those in multiple other studies1-10, yet the orthopaedic literature continues to challenge the use of interscalene regional block. Many of these conflicting studies are from community hospitals rather than university-based hospitals11. In particular, Weber and Jain reported on a retrospective review of 218 patients who had had shoulder surgery under interscalene regional block at a free-standing surgery center and a community hospital11. They reported a block failure rate of 13% (twenty-eight patients) and a complication rate of 4% (eight patients). The complications in their study were more acute than those in our study and included four patients who had respiratory distress due to phrenic nerve injuries, one patient who had a grand mal seizure, one who had cardiovascular collapse, and two who had temporary nerve injuries that persisted at six weeks. Therefore, their reluctance to offer interscalene regional block is understandable. Although our complication rate was 2.3% (twelve of 512 patients), it consisted primarily of sensory neuropathies, which resolved by an average of nine weeks. In addition, our block failure rate was only 3% (sixteen of 478 patients).
Several studies have warned against the use of interscalene regional block because of a high complication rate11-13. The possible complications, including cardiac arrest, grand mal seizures, high spinal blocks, hematoma, pneumothorax, phrenic nerve palsy, and respiratory distress, and the rates of occurrence of these complications have been well described1,6,11,12,14-26. The experience of our anesthesia team may have contributed to our lower complication rate as they are dedicated to the concept of regional anesthesia and practice it on a daily basis. In addition, the anesthetic techniques they use have been continually refined to improve outcomes and reduce risks27-31.
Of our ten patients who had postoperative paresthesias, five had symptoms on the ulnar side. These complications could possibly have been due to the use of an arm holder and/or the positioning of the limb during surgery. The ulnar nerve is anatomically derived from the lower cervical roots and is blocked by the interscalene regional block only 40% of the time32. Ulnar neuropathies due to positioning are known to occur more frequently than median nerve symptoms, primarily because of the superficial path that the ulnar nerve takes near the elbow33,34.
Conflicting results have also been reported with regard to nonsurgical operating-room times for those receiving interscalene regional block compared with those managed with general anesthesia. We found, as have several others, that these times are less for those receiving an interscalene regional block1,3,4,35. The difference in the nonsurgical times for our patients managed with interscalene regional block and those who had general anesthesia was twenty-seven minutes. Although we did not examine recovery room times, several studies have described a shorter stay in the recovery room after interscalene regional block and our experience is that many of our patients who have an interscalene regional block do not even need this phase of the recovery process2,3,10,35.
One limitation of this retrospective study is that the intravenous sedation, which is necessary to ensure patient comfort in the sitting position for extended periods of time, was not standardized. Other investigators have considered the need for intravenous narcotics on arrival in the recovery room to be an indication of block failure11. However, the majority of these patients had both general anesthesia and an interscalene regional block. Thus, intraoperative identification of block failure was not possible. As the majority of our patients received interscalene regional block alone, block failure was immediately evident. Thus, administration of a combination of intravenous medications was performed to achieve relief of positional discomfort and any patient anxiety or restlessness. We believe that this is an adjunct to a successful block, not a solution for an unsuccessful block.
In conclusion, interscalene regional block can provide effective anesthesia for most types of shoulder surgery, including arthroplasty and fracture fixation. We showed that interscalene regional block, when administered by an anesthesiologist committed to and skilled in the technique, has a high degree of success and a low rate of complications.
A table listing all block failures is available with the electronic versions of this article, on our web site at jbjs.org (go to the article citation and click on “Supplementary Material”) and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM). ▪
The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Investigation performed at the Leni and Peter W. May Department of Orthopaedics, Mount Sinai Hospital, New York, NY
1. , Weiss R, Greenberg C, Flatow EL, Bigliani LU. Interscalene block for shoulder arthroscopy: comparison with general anesthesia. Arthroscopy. 1993;9: 295-300.
2. , Rouse LM, Chen JM, Miller RJ. Comparison of postoperative pain in patients receiving interscalene block or general anesthesia for shoulder surgery. Orthopedics. 2002;25: 45-8.
3. , Greger J, Al Samsam T, Gebhard R, Masson M, Matuszczak M, Sciard D. Reduction of operating and recovery room times and overnight hospital stays with interscalene blocks as sole anesthetic technique for rotator cuff surgery. Minerva Anestesiol. 2001;67: 613-9.
4. , Rosenblum M, Shea KP, Freitas DG. A retrospective comparison of interscalene block and general anesthesia for ambulatory surgery shoulder arthroscopy. Reg Anesth. 1995;20: 62-8.
5. , Yoon HJ, Brems J. Patient acceptance of interscalene block for shoulder surgery. Reg Anesth. 1993;18: 30-3.
6. , Ekatodramis G, Kalberer F, Benz C. Acute and nonacute complications associated with interscalene block and shoulder surgery: a prospective study. Anesthesiology. 2001;95: 875-80.
7. , Taylor DC, Harrison SA, Snyder RJ, Leahy KE, Uhorchak JM. Interscalene anesthesia for shoulder arthroscopy in a community-sized military hospital. Arthroscopy. 1996;12: 715-9.
8. , Freitas D, Rosenblum M, Shea K. Is general anesthesia superior to interscalene block for shoulder surgery? Anesth Analg. 1993;76: 67.
9. , Truchon R, St-Pierre A, Montreuil J. Interscalene block for pain relief after shoulder surgery. A prospective randomized study. Clin Orthop. 1994;304: 22-4.
10. , Greek R, Torjman M, Lessin J, Marr A, Fenlin J, Seltzer J. Is regional anesthesia more time efficient than general anesthesia for shoulder surgery. Anesthesiology. 1993;79: 897.
11. , Jain R. Scalene regional anesthesia for shoulder surgery in a community setting: an assessment of risk. J Bone Joint Surg Am. 2002;84: 775-9.
12. . Environment. In: McGinty J, editor. Arthroscopy. New York: Raven Press; 1991. p 16-22.
13. , Huber C, Riccabona UM, Schlager A. Medicolegal aspects of patient information before regional anesthesia in Austria. Acta Anaesthesiol Scand Suppl. 1997;111: 229-31.
14. , Talts KH, Sharrock NE. One hundred percent incidence of hemidiaphragmatic paresis associated with interscalene brachial plexus anesthesia as diagnosed by ultrasonography. Anesth Analg. 1991;72: 498-503.
15. , Morelli C, Coleman S, Holmes T, Allen A, Altcheck D, Cordasco F, Warren R, Urban M, Gordon M. Complications of interscalene block anesthesia in ambulatory shoulder surgery. Read at the Annual Meeting of the American Shoulder and Elbow Surgeons; 2002 Feb 15; Orlando, FL.
16. , Lear E, Azar I, Salzer J, Zeiligsohn E. Bronchospasm following interscalene brachial plexus block. Anesthesiology. 1984;61: 759-61.
17. , Cofield RH, Byer DE, Linstromberg JW. Interscalene block anesthesia for shoulder surgery. Clin Orthop. 1987;216: 94-8.
18. , Ransom DM, Hall JA, Leicht CH, Schroeder DR, Offord KP. Regional anesthesia and local anesthetic-induced systemic toxicity: seizure frequency and accompanying cardiovascular changes. Anesth Analg. 1995;81: 321-8.
19. , Deutsch S. Cardiac arrest after interscalene brachial-plexus block. Anesth Analg. 1977;56: 446-7.
20. . Unsuspected extradural catheterization in an interscalene block. Br J Anaesth. 1991;67: 473-5.
21. . Total spinal anesthesia after an interscalene block. J Perianesth Nurs. 1997;12: 163-8.
22. , Kelley H, Carrithers J. Perceptions of side effects following axillary block used for outpatient surgery. Reg Anesth. 1995;20: 212-6.
23. , Weller RS, Rosenblum M. Activation of the Bezold-Jarisch reflex in the sitting position for shoulder arthroscopy using interscalene block. Anesth Analg. 1995;80: 1158-62.
24. , Dick MM. Phrenic nerve paralysis following interscalene brachial plexus block. Anesth Analg. 1983;62: 536-7.
25. . Hoarseness and Horner's syndrome after interscalene brachial plexus block. Anesth Analg. 1977;56: 585-6.
26. , Mertz J, Geller B. Postoperative onset of idiopathic brachial neuritis. Anesthesiology. 1996;84: 455-8.
27. , Pither C, Raj PP. Comparison of insulated and uninsulated needles for locating peripheral nerves with a peripheral nerve stimulator. Anesth Analg. 1984;63: 925-8.
28. . Brachial plexus block with the nerve stimulator: motor response characteristics at three sites. Reg Anesth. 1992;17: 295-9.
29. , Raj PP, Nettles D, Jenkins MT. The use of the nerve stimulator with standard unsheathed needles in nerve blockade. Anesth Analg. 1973;52: 827-31.
30. , Chung F. Postoperative analgesic effect of low-dose bupivacaine for interscalene brachial plexus block for shoulder surgery. A dose finding study. Arthroscopy. 1998;14: 446-7.
31. , Christiansen C, Hansen A, Sorensen M, Meisler C. Interscalene brachial plexus block: area of analgesia, complications and blood concentrations of local anesthetics. Acta Anesthesiol Scand. 1981;25: 81-4.
32. . Textbook of regional anesthesia. New York: Churchill Livingstone; 2002. p 515.
33. . Postoperative peripheral neuropathies. Surgery. 1973;74: 348-57.
34. , Lincoln JR. Peripheral nerve injuries with anesthesia: a review and report of three cases. Anesth Analg. 1966;45: 748-53.
Copyright 2005 by The Journal of Bone and Joint Surgery, Incorporated
35. , Rapp SE, Polissar NL, Malmgren JA, Koerschgen M, Keyes H. Factors affecting discharge time in adult outpatients. Anesth Analg. 1998;87: 816-26.