| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
From the Department of Anesthesiology and Pain Management, University Health Network and Mount Sinai Hospital, Wasser Pain Management Center, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
Address correspondence to: Dr. Philip Peng, Department of Anesthesiology and Pain Management, EC 2-046 Toronto Western Hospital, 399 Bathurst Street, Toronto, Ontario M5T 2S8, Canada. Phone: 416-603-5118; Fax: 416-603-6494; E-mail: Philip.peng{at}uhn.on.ca
 |
Abstract |
|---|
 TOP Abstract IntroductionMethodologyResultsDiscussionConclusionReferences |
|---|
Methods: Following hospital Ethics Committee approval, a detailed postal questionnaire was sent to all active members of the Canadian Anesthesiologists’ Society. A second mailing was conducted two months later.
Results: The overall response rate was 53%. While 38% of responding anesthesiologists were involved in CPP, in the majority of cases, this accounted for less than 20% of their clinical time. Thirty percent of those involved in CPP had previous training in pain management. The types of CPP included nerve blocks (84%) and pharmacological treatment (60%) in non-cancer pain (85%) and cancer pain (50%) patients. Ten percent and 28% of anesthesiologists were involved in research and teaching respectively while 26% were affiliated with a multidisciplinary clinic. The healthcare professions that anesthesiologists had access to or were directly working with in their practice were as follows: acupuncture (18%), nursing (36%), psychology (28%), psychiatry (35%) and physiotherapy (58%). Epidural steroid injection was the most commonly practiced intervention (82%). This was followed by trigger point injection (70%), stellate ganglion block (61%), occipital nerve block (60%) and lumbar sympathetic block (50%). Practice of interventional procedures was highly diverse.
Seventy percent of anesthesiologists prescribed opioids as part of their CPP. However, half of them never incorporated an opioid agreement with patients. Opioids were most commonly used in the sustained release form.
Conclusion: Approximately one-third of anesthesiologists surveyed incorporate chronic pain in their practice and their pattern of practice is widely diversified.
|
Introduction |
|---|
|
TOPAbstractIntroductionMethodologyResultsDiscussionConclusionReferences |
|---|
|
Methodology |
|---|
|
TOPAbstractIntroductionMethodologyResultsDiscussionConclusionReferences |
|---|
Following hospital Ethics Committee approval, a four-page questionnaire was pilot tested and, subsequently, sent to all active members of the Canadian Anesthesiologists’ Society. Students, residents, retired or inactive members, and those members outside of the country were excluded. A second mailing was conducted two months later. The results are presented as frequency and percentage. Background information was compared using the Chi-square test. A P value of < 0.05 was regarded as statistically significant.
|
Results |
|---|
|
TOPAbstractIntroductionMethodologyResultsDiscussionConclusionReferences |
|---|
Chronic pain management was part of the practice of 38% of anesthesiologists surveyed. However, this practice was limited in the majority of these individuals (Figure 1
). Comparison of the gender, age, training in chronic pain management and setting of practice with all anesthesiologists surveyed is shown in Table I. Only 15% of all anesthesiologists (with and without CPP) had previous training in chronic pain management (fellowship 43%; observership 57%). Of those with a practice in chronic pain management, this increased to 30% (fellowship 42%; observership 58%).
|
|
. Fifty-three percent of the respondents estimated that more than 40% of their patients required a nerve block as part of their pain management.
|
). This procedure was most commonly performed outside the operating room (procedure room 37%; recovery room 30%). While 16% of anesthesiologists performed ESI in the operating room, 3.7% of anesthesiologists performed ESI in their office. The commonest level for performance of ESI was lumbar spine (99%). This was followed by thorax (44%), cervical (37%) and caudal (34%) ESI. The volume of injectate most commonly chosen was between 6 to 10 mL (61%). Most anesthesiologists (67%) combined local anesthetic with steroid (saline + steroid – 20%; opioids + steroid – 11%; steroid only 2.7%). None of the anesthesiologists performing ESI chose an injectate volume of more than 20 mL. Methylprednisolone was the most popular choice of steroid (78%) and the dose most commonly chosen was between 61 to 100 mg (65%). Most of the anesthesiologists performed ESI without radiological guidance (77%) while 5% routinely used x-rays for this procedure.
|
. The maximum number of ESI that could be performed in a six-month period was considered by most anesthesiologists to be 3 (mode). In the event of an accidental dural puncture, most anesthesiologists (62%) would postpone the procedure. This compares with 36% who would try at a different level and 2% who would repeat at the same level. Hemostasis altering drugs that anesthesiologists would consider discontinuing before ESI are listed in Table III.
|
). The majority of anesthesiologists (84%) who performed chemical sympathectomy preferred a diagnostic local anesthetic block before neurolysis. The rest would consider neurolysis as the initial procedure for patients with cancer pain or vascular insufficiency.
|
). The majority (83%) used the classical approach with a needle insertion at the C6 level. Two percent of anesthesiologists always performed this procedure with x-ray guidance.
Facet blocks
Facet joint or nerve blocks were performed by 27% of anesthesiologists with CPP. The choices of techniques are summarized in Table V. Of those performing facet joint or nerve block, 29% also performed radiofrequency neurolysis. Two-thirds of this group would consider performing two diagnostic blocks before the radiofrequency procedure.
|
). Approximately half of those who prescribed opioids never used an opioid agreement or contract (Table VI). Support from the family doctor for opioid prescription was felt to be poor or very poor in 32%. Access to an addiction specialist was readily available in 16% of anesthesiologists prescribing opioids.
|
Injection of botulinum toxin (Botox®)
Botox® injection was part of the practice of 11% of anesthesiologists. This therapy was used in the treatment of neck pain (89%), back pain (63%), headache (50%), craniofacial pain (37%) and fibromyalgia (19%).
|
Discussion |
|---|
|
TOPAbstractIntroductionMethodologyResultsDiscussionConclusionReferences |
|---|
To date, no survey has described CPP in anesthesiologists. In the present survey, it was found that there was a wide variation in the practice of different procedures and opioid prescription practice. Only a few selected topics will be commented upon because of their potential interest or controversial nature.
ESI
ESI was the most commonly performed interventional procedure by anesthesiologists with CPP in our survey. Despite half a century of experience, there is no consensus as what is the "proper" technique.5,6 Similar to the national survey on the practice of ESI in the U.S.,7 a wide variation of techniques was found in the present survey.
There are a few interesting findings in our survey. Slightly less than 4% of anesthesiologists chose to perform ESI in their office. Although ESI is considered to be a very safe procedure, life-threatening complications can occur8 and ESI was the major cause of malpractice claims in chronic pain management both in Canada and the United States.9,10 It should be performed in a location where resuscitation equipment and personnel are immediately available, particularly when a local anesthestic is used. The only widely accepted indication for ESI is pain associated with radiculopathy.6 However, 5.5% of anesthesiologists in our survey considered back pain alone an indication. Ten percent of the surveyed anesthesiologists would add an opioid to the steroid for injection. This is rarely practiced in the United States, where less than 2% of institutions, exclusively academic, would add an opioid to the injectate.7 While there is no evidence to support the benefit of adding an opioid to ESI injection, a recent closed claim study showed that death or brain death was observed only in the cases where an opioid or local anesthetic was injected concomitantly with the epidural steroid.10 Although a cause and effect relationship cannot be established in a closed claim study, clinicians performing ESI should judge the benefit against the risk when adding an opioid to the injection.
While there is no literature to suggest the maximum number of ESI per year, Cushing’s syndrome and adrenal suppression have been reported after paraspinal injections of 150 to 290 mg triamcinolone over a three-month period.11 Weekly epidural injections of 80 mg triamcinolone for three weeks also resulted in acute suppression of plasma adrenocorticotrophin (ACTH) and cortisol levels for a month following the last injection.12 The cortisol response to synthetic ACTH (cosyntropin) was also blunted in 36% of the same group of patients in the month following the last injection. This returned to normal in all patients three months after the last injection. In our survey, most anesthesiologists would perform three injections in a six-month period (range 1 to 6). Interestingly, the maximum number of injections in a year ranged from 0 to 40 among anesthesiologists in the United States.7
There is no consensus on the optimal volume, dose and type of medication used for injection. Since the target epidural space is on the ventral aspect of the dura (such as inflammation from a herniated disc), a higher volume of injectate will promote spread of medication from the site of injection on the dorsal aspect of dura. However, injectate volumes of 10 to 20 mL have been shown to increase intrathecal pressure for ten minutes13 and a larger volume (> 40 mL) may lead to retinal hemorrhage or visual disturbance.14 An injection volume of up to 10 mL has been recommended.5
Sympathetic blocks
Sympathetic blocks are commonly performed by anesthesiologists for the management of patients with CRPS, circulatory insufficiency and cancer pain.15,16 The sympathetic chain and its ganglia for the lumbar region lie close to the anterolateral aspect of the vertebral bodies, separated from somatic nerves by the psoas fascia and muscle.16 Although the locations of the ganglia are quite variable, ganglia are more likely to be present at the L3 level.17 Various approaches of LSB have been described, from a single level injection with a high volume of local anesthetic (e.g., 20 mL) to multilevel injections with smaller volumes of injectate.18 No study to date has demonstrated the superiority of one approach over the other. In our survey, the most popular technique is a single level injection.
Confirmation of needle position with an x-ray is necessary when performing neurolytic blocks of the lumbar sympathetic ganglia.16 However, opinions on the role of fluoroscopy when only local anesthetic is used vary. One quarter of the anesthesiologists surveyed did not use fluoroscopy for LSB in their practice. A ‘loss of air resistance’ technique can also be used to locate the ‘correct’ position of needle tip.16 The safety of this ‘blind’ technique was examined in a cadaver study.19 Three of out 80 needle attempts resulted in the needles embedded in grossly osteoporotic vertebral bodies or hilum of the kidney. All incorrect placements would have been prevented by the use of fluoroscopy.
Facet blocks
The prevalence of lumbar facet or zygapophysial joint pain in chronic low back pain patients ranges from 15 to 52%.20 Management of lumbar facet joint pain has included intra-articular injections of steroid, percutaneous denervation using radiofrequency electrodes, chemical or cryogenic techniques, pharmacotherapy, physical therapy and manipulation.21 Before the treatment, identification of the lumbar facet joints as sources of low back pain can be made with diagnostic facet blocks. For the purpose of diagnosis, medial branch block and intra-articular facet joint injection are believed to have equal diagnostic sensitivity.21,22 The lumbar medial branch block has been shown to be highly target specific.23 Dual blocks (a series of two diagnostic blocks) of the facet joints or the medial branch are recommended for a more secure diagnosis, especially before the patients are considered for medial branch neurotomy. This is because of an unacceptable false-positive or placebo rate associated with single nerve blocks.21 The false positive rate of single injection is 38% using a dual block protocol.24 Dual medial branch blocks using lidocaine and bupivacaine can substantially reduce the likelihood of a false-positive or placebo response.21 Either intra-articular injection or medial branch block should be performed under fluoroscopic guidance.21 A slight (few mm) misplacement of the needle off the target point can result in a higher incidence of aberrant spread such as spread to the intervertebral neural foramen and epidural space,23 which will result in a falsely positive result.
Opioid prescription practice
One-third of the anesthesiologists with CPP never prescribe opioids. This may be attributed to the fact that interventional procedures are an important component of practice of the anesthesiologists surveyed (84% anesthesiologists included nerve blocks in their practice). Although 60% included pharmacotherapy in their practice, only a few of them obtained nursing support (36%) or worked in a multidisciplinary clinic (26%). This may explain the low utilization of opioids in their practice. Other possibilities include physicians’ concern about the risk of addiction and the fear of disciplinary action from regulatory agencies.25
Opioid therapy is well established as an invaluable treatment for acute pain and cancer-related pain. However, the opinion regarding the appropriate use of opioid therapy in CNCP is not as clear.26 In the past decade, research has shown that opioid therapy can relieve pain and improve mood and functioning in many patients with CNCP.27,28 The recognition of this led to the consensus statements published by the American Pain Society, American Academy of Pain Medicine and Canadian Pain Society.26,29 Despite this recognition from the medical societies, opioid therapy is still underutilized for the treatment of CNCP. A recent survey on chronic pain in Canada showed that 80% of patients with chronic pain taking prescription analgesics suffered from moderate to severe pain. However, only one-fifth of them were managed with an opioid analgesic.25
Opioid contract or agreement is frequently used in the opioid management of CNCP.30 This is an agreement, either verbal or written, between the prescribing physicians and the patients in how the opioid medications can be prescribed safely. However, only half of the opioid-prescribing anesthesiologists in the present survey used an opioid agreement. A recent consensus statement and guidelines published by the Canadian Pain Society on the use of opioid analgesics for the treatment of CNCP suggests a documented verbal consent in most practice settings.26 This includes a discussion of the risks and benefits of opioid therapy, as well as the conditions under which opioids will be prescribed. However, they recommend a written therapeutic agreement for patients assessed to be at higher risk of noncompliance with the verbally agreed treatment plan.26
The majority of anesthesiologists prefer the use of sustained release preparations (e.g., MS Contin®, Purdue Pharma, Pickering, ON, Canada) or long-acting (e.g., methadone) opioids for managing chronic pain patients. These two forms of opioid preparations have many advantages in treating chronic pain. It can improve the pain control and patient compliance with a round-the-clock and time-contingent dosing schedule. With a more consistent blood level of opioid, the tolerance to side effects such as cognitive impairment improves. It also may reduce the risk of addiction by avoiding the reinforcement seen in prn dosing regimens.26
Limitations of the study
The overall response rate was 53%, similar to other national surveys of Canadian anesthesiologists.3,4 However, only 38% of respondents practice chronic pain management. Thus, information on CPP was obtained from approximately 20% of practicing anesthesiologist in Canada (n = 267).
It is possible that the survey overestimates the proportion of anesthesiologists with CPP, as the respondents were more likely to have a CPP. To minimize the bias of response, the questionnaire was designed in such a way that those who have no CPP were encouraged to return their questionnaires after completion of a few questions on background information. A copy of the four-page questionnaire is available as Additional Material at www.cja-jca.org.
|
Conclusion |
|---|
|
TOPAbstractIntroductionMethodologyResultsDiscussionConclusionReferences |
|---|
|
Acknowledgments |
|---|
|
Footnotes |
|---|
Assessed March 30, 2004. Revision accepted May 19, 2004. Final revision accepted January 14, 2005.
|
References |
|---|
|
TOPAbstractIntroductionMethodologyResultsDiscussionConclusionReferences |
|---|
2 Wilson P. Comprehensive pain rehabilitation program: a North American perspective. In: Jensen TS, Wilson PR, Rice ASC (Eds). Clinical Pain Management: Chronic Pain, 1st ed. London: Arnold; 2003: 163–72.
3 Jenkins K, Wong D. A survey of professional satisfaction among Canadian anesthesiologists. Can J Anesth 2001; 48: 637–45.
4 Breen TW, McNeil T, Dierenfield L. Obstetric anesthesia practice in Canada. Can J Anesth 2000; 47: 1230–42.[Abstract]
5 Walsh E. Epidural steroid injections for back pain and sciatica. In: Breivik H, Campbell W, Eccleston C (Eds). Clinical Pain Management: Practical Applications and Procedures, 1st ed. London: Arnold; 2003: 417–30.
6 Abram SE. Treatment of lumbosacral radiculopathy with epidural steroids. Anesthesiology 1999; 91: 1937–41.[Medline]
7 Cluff R, Mehio AK, Cohen SP, Chang Y, Sang CN, Stojanovic MP. The technical aspects of epidural steroid injections: a national survey. Anesth Analg 2002; 95: 403–8.
8 Abram SE, O’Connor TC. Complications associated with epidural steroid injections. Reg Anesth 1996; 21: 149–62.[Medline]
9 Peng PW, Smedstad KG. Litigation in Canada against anesthesiologists practicing regional anesthesia. A review of closed claims. Can J Anesth 2000; 47: 105–12.
10 Fitzgibbon DR, Posner KL, Domino KB, Caplan RA, Lee LA, Cheney FW. Chronic pain management. American Society of Anesthesiologists closed claims project. Anesthesiology 2004; 100: 98–105.[Medline]
11 Edmonds LC, Vance ML, Hughes JM. Morbidity from paraspinal depo corticosteroid injections for analgesia: Cushing’s syndrome and adrenal suppression. Anesth Analg 1991; 72: 820–2.
12 Kay J, Findling JW, Raff H. Epidural triamcinolone suppresses the pituitary-adrenal axis in human subjects. Anesth Analg 1994; 79: 501–5.
13 Usubiaga JE, Usubiaga LE, Brea LM, Goyena R. Effect of saline injections on epidural and subarachnoid space pressures and relation to postspinal anesthesia. Anesth Analg 1967; 46: 293–6.
14 Purdy EP, Ajimal GS. Vision loss after lumbar epidural steroid injection. Anesth Analg 1998; 86: 119–22.[Medline]
15 Boas RA. Sympathetic nerve blocks: in search of a role. Reg Anesth Pain Med 1998; 23: 292–305.[Medline]
16 Breivik H. Sympathetic blocks. In: Breivik H, Campbell W, Eccleston C (Eds). Clinical Pain Management: Practical Applications and Procedures, 1st ed. London: Arnold; 2003: 233–46.
17 Rocco AG, Palombi D, Raeke D. Anatomy of the lumbar sympathetic chain. Reg Anesth 1995; 20: 13–9.[Medline]
18 Breivik H, Cousins MJ, Löfström JB. Sympathetic neural blockade of upper and lower extremity. In: Cousins MJ, Bridenbaugh PO (Eds). Neural Blockade in Clinical Anesthesia and Management of Pain, 3rd ed. Philadelphia: Lippincott-Raven; 1998: 411–50.
19 Cherry DA, Rao DM. Lumbar sympathetic and coeliac plexus blocks. An anatomical study in cadavers. Br J Anaesth 1982; 54: 1037–9.
20 Slipman CW, Bhat AL, Gilchrist RV, Issac Z, Chou L, Lenrow DA. A critical review of the evidence for the use of zygapophysial injections and radiofrequency denervation in the treatment of low back pain. Spine J 2003; 3: 310–6.[Medline]
21 Dreyfuss P, Dreyer SJ. Lumbar zygapophysial (facet) joint injections. Spine J 2003; 3(Suppl): 50S–9S.[Medline]
22 Marks RC, Houston T, Thulbourne T. Facet joint injection and facet nerve block: a randomised comparison in 86 patients with chronic low back pain. Pain 1992; 49: 325–8.[Medline]
23 Dreyfuss P, Schwarzer AC, Lau P, Bogduk N. Specificity of lumbar medial branch and L5 dorsal ramus blocks. A computed tomography study. Spine 1997; 22: 895–902.[Medline]
24 Schwarzer AC, Aprill CN, Derby R, Fortin J, Kine G, Bogduk N. The false-positive rate of uncontrolled diagnostic blocks of the lumbar zygapophysial joints. Pain 1994; 58: 195–200.[Medline]
25 Moulin DE, Clark AJ, Speechley M, Morley-Forster PK. Chronic pain in Canada - prevalence, treatment, impact and the role of opioid analgesia. Pain Res Manage 2002; 7: 179–84.
26 Jovey RD, Ennis J, Gardner-Nix J, et al. Use of opioid analgesics for the treatment of chronic noncancer pain - a consensus statement and guidelines from the Canadian Pain Society, 2002. Pain Res Manage 2003; 8(Suppl A); 3A–14A.
27 Portenoy RK, Foley KM. Chronic use of opioid analgesics in non-malignant pain: report of 38 cases. Pain 1986; 25:171–86.[Medline]
28 McQuay H. Opioids in pain management. Lancet 1999; 353: 2229–32.[Medline]
29 Anonymous. The use of opioids for the treatment of chronic pain. A consensus statement from the American Academy of Pain Medicine and the American Pain Society. Clin J Pain 1997; 13: 6–8.[Medline]
30 Fishman SM, Kreis PG. The opioid contract. Clin J Pain 2002; 18: S70–S5.[Medline]
This article has been cited by other articles:
 |
|
 |
|
  I. Gilron, C. P. N. Watson, C. M. Cahill, and D. E. Moulin Neuropathic pain: a practical guide for the clinician. Can. Med. Assoc. J., August 1, 2006; 175(3): 265 - 275. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. W. H. Peng, P. S. Tumber, and D. Gourlay Review article: Perioperative pain management of patients on methadone therapy: [Expose de synthese : Traitement de la douleur perioperatoire chez les patients sous therapie a la methadone] Can J Anesth, May 1, 2005; 52(5): 513 - 523. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Rashiq Clinical freedom's final refuge/Le dernier abri de l'independance clinique Can J Anesth, April 1, 2005; 52(4): 352 - 355. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
