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Abstract
Background Although there is a low incidence of complications associated with epidural injections, pain physicians should still remain vigilant for potentially serious adverse outcomes. This study aimed to identify and describe the major complications of epidural injections.
Methods This retrospective, observational, medicolegal study analyzed closed cases of precedents involving complications of epidural injections from January 1997 to August 2019 using the database of the Supreme Court of Korea’s judgement system. Clinical characteristics and judgement statuses were analyzed.
Results Of the 73 potential cases assessed for eligibility, a total of 49 malpractice cases were included in the final analysis. Thirty-three claims resulted in payments to the plaintiffs, with a median payment of US$103 828 (IQR: US$45 291–US$265 341). The most common complication was infection (n=13, 26.5%), followed by worsening pain (n=8, 16.3%). Physician malpractice before, during, and after the procedure was claimed by plaintiffs in 18 (36.7%), 44 (89.8%), and 31 (63.3%) cases, respectively. Of these cases, 6 (33.3%), 19 (43.2%), and 15 (48.4%), respectively, were adjudicated in favor of the plaintiffs by the courts. In cases involving postprocedural physician errors, the majority (13/15) of the plaintiff verdicts were related to delayed management. Violation of the physician’s duty of informed consent was claimed by plaintiffs in 31 (63.3%) cases, and 14 (45.2%) of these cases were judged medical malpractice.
Conclusions Our data will allow pain physicians to become acquainted with the major epidural injection-associated complications that underlie malpractice cases.
- chronic pain
- complications
- epidural injection
- legislation and jurisprudence
- spinal diseases
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Introduction
Epidural injections are widely used as a component of a multimodal treatment program for degenerative spinal diseases.1 2 Several drugs, including corticosteroids, local anesthetics, and hyaluronidase, can be injected into the epidural space to improve pain control.3 4 The epidural injection method can be classified as transforaminal, interlaminar, or caudal based on the approach to the epidural space. Although the effectiveness of epidural injections in degenerative spinal diseases remains debatable,5 6 the frequency of epidural injections has increased dramatically as the prevalence of these disorders has increased and the interest in non-invasive treatment strategies has grown.7 With an increase in degenerative spinal diseases in an ageing population, it is likely that the number of patients undergoing epidural injections will continue to rise.8
Epidural injections carry the risk of potentially serious complications, including infection, hematoma, neurologic injury, and even death.9 Nevertheless, several studies have demonstrated that epidural injections in patients with chronic pain are relatively safe, with low rates of serious complications.10–12 As a result, many pain physicians may have limited experience in managing these rare and severe complications, which may contribute to poor outcomes, including fatal injury to patients and medical malpractice cases.
An analysis of medical malpractice legal judgements may be helpful for the identification and prevention of malpractice claims associated with the rare, but severe, complications of epidural injections in patients with chronic pain. This study analyzed medical malpractice lawsuits and their judgements in epidural injection cases in the South Korean court system. Through this study, we hope to increase awareness of the major complications of epidural injections and to call attention to the rare, but important, adverse outcomes of these procedures.
Methods
We analyzed closed cases of precedents that are publicly accessible in the database of the Supreme Court of Korea’s judgement system. This database contains civil proceeding decisions from the district court level to the Supreme Court. The judgements were provided to the researcher without identifiable information. All medical malpractice litigation cases that were decided by the court from 1 January 1997 to 31 August 2019 were queried using the search terms ‘epidural’ and ‘nerve block’. We excluded cases unrelated to epidural injections and the complications of this procedure.
Each judgement text contained a detailed narrative of the case, the malpractice claims of the plaintiff, and the court decisions regarding medical malpractice. Two board-certified pain physicians (HJL and HJ) reviewed the judgement texts and collected the following information: age, sex, underlying medical diseases, history of surgery or other interventions in the same anatomical area as the epidural injection, procedural information of the epidural injection, the time interval between the procedure and the onset of complications (injury became apparent in the medical institution or injury became apparent after discharge), and the types and severities of the complications.
The types of complications were classified as follows: infection, spinal cord infarction, needle trauma to nerve or cord, unintended intravascular or intrathecal injection, epidural hematoma, and others. The severity of complications was scored using the 10-point National Association of Insurance Commissioners (NAIC) scale in which 0 is ‘no obvious injury’ and 9 is ‘death’.13 Data regarding the detailed claims of plaintiffs, the opinions of the court, and the final awarded amounts were also collected. The plaintiffs’ allegations were classified into the following four categories: malpractice before the procedure (eg, diagnostic error, insufficient patient evaluation), malpractice during the procedure (eg, inadequate sterile technique, no imaging device guidance, particulate steroid injection), malpractice after the procedure (eg, delayed treatment), and a lack of informed consent. Each case was investigated to determine if it was accepted by the court.
Descriptive statistical analyses were performed using the SPSS software V.25.0 (IBM). Categorical data are described as percentages, and comparisons between groups were made using the χ2 or Fisher’s exact test as appropriate. Continuous data are described as medians (IQR), and comparisons between groups were made using the Mann-Whitney U test. A p value <0.05 was considered statistically significant.
Results
Of the 73 potential cases assessed for eligibility, 24 were excluded and 49 were included in the final analyses (figure 1). Clinical characteristics of the patients and their epidural injections are presented in table 1. The most common pain disease was spinal stenosis (n=16, 32.7%), and 44.9% of patients (n=22) had previously received pain procedures in the same area. The most common site of the procedure was the lumbosacral area (n=34, 69.4%), and the most common type of approach was interlaminar (n=31, 63.3%). There were no significant differences between the cervical and lumbar epidural injections except for in the history of surgery in the same anatomical area as that of the procedure. The number of patients and epidural injection procedures performed in Korea from 2010 to 2017 is presented in online supplementary table S1.
Supplemental material
General characteristics of the cases
Flow sheet in this study.
Judgement statuses are shown in table 2. A total of 33 claims (67.3%) resulted in payments to the plaintiffs, with a median payment of US$103 828 (IQR: US$45 291–US$265 341). Sixteen cases (32.7 %) were dismissed by the court. Physician malpractice before, during, or after the procedure was claimed by plaintiffs in 17 (34.7%), 44 (89.8%), and 31 (63.3%) of cases, respectively. Of these cases, 6 (35.3%), 19 (43.2%), and 15 (48.4%) were ruled physician malpractice by the court, respectively. Preprocedural errors that were ruled physician malpractice included unnecessary epidural injections due to diagnostic error (n=2, plantar fasciitis, spinal dural arteriovenous fistula) and insufficient patient evaluation (n=4). Malpractices related to insufficient patient evaluation were as follows: no coagulation test prior to the procedure (epidural hematoma case), no coagulation test and no cessation of warfarin before the procedure in a patient taking warfarin (epidural hematoma case), no imaging tests before the cervical epidural block (unintended intravascular or intrathecal injection case), and negligence of a patient’s fever and chills before the procedure (infection case). Errors that occurred during the procedure that were ruled physician malpractice included improper performance of the procedure, not otherwise specified (n=7); inadequate sterile technique (n=5); procedure without imaging device guidance (n=3); particulate steroid injection (n=3); and pneumocephalus due to loss of resistance with air (n=1). Postprocedural errors that were ruled physician malpractice included delayed treatment (n=14) (see online supplementary table S2) and no further examination of pain that persisted after epidural injection (n=1, final diagnosis; plantar fasciitis). Violation of the physician’s duty of informed consent was claimed by plaintiffs in 31 (63.3%) cases. Of these cases, 14 (45.2%) were ruled medical malpractice by the court.
Judicial characteristics from 49 cases related to epidural steroid injection
Details of each major complication are shown in table 3. The most commonly identified type of complication was infection (n=13, 26.5%) (figure 2). Four of the 13 infection cases were dismissed. In these cases, the court acknowledged that it was difficult to completely prevent in-hospital infections and that there was no evidence of an inadequate sterile technique. Inadequate sterile technique was recognized as a cause for malpractice in five cases.
Type of alleged complications. IT, intrathecal; IV, intravascular.
Clinical and judicial characteristics according to the mechanisms of major complications
The use of triamcinolone, a particulate steroid, was recognized to be a cause for malpractice in three cases of spinal cord infarction. One case of spinal cord infarction was dismissed. Although triamcinolone was also used in this case, it was not recognized as malpractice because the administration of triamcinolone into the epidural space had not been restricted at that time.
In seven of the 11 cases of needle trauma to nerve or cord or inadvertent intravascular/intrathecal injection, the court ruled for malpractice during the procedure. In three of these cases, the lack of imaging device guidance was recognized as a cause for malpractice. All six cases related to inadvertent intravascular or intrathecal injection were associated with hypoxic encephalopathy. In the five epidural hematoma cases, there were two patients taking antithrombotic agents (one case of mitral valve replacement therapy with warfarin and one case of arrhythmia with antithrombotic agent). In two cases of epidural hematomas, lack of a coagulation test was recognized as preprocedural malpractice. All postprocedural malpractices related to infection, needle trauma to nerve or cord, inadvertent intravascular/intrathecal injection, and epidural hematoma cases were associated with delayed management.
There were a total of eight deaths, three of which were related to infections, one related to needle trauma to nerve or cord, one related to inadvertent intravascular/intrathecal injection, and three related to underlying myocardial infarctions confirmed by autopsy. Of these cases, the three cases associated with infections included an epidural abscess complicated by infective endocarditis, a necrotizing fasciitis, and an epidural abscess only (see online supplementary table S2 Case No 9, 11, and 14, respectively). The final causes of death in these three cases were sepsis. In addition, a patient with needle trauma also died from sepsis after long-term bed rest (see online supplementary table S2 Case No 4). There were four cases of patients in vegetative states, all associated with inadvertent intravascular/intrathecal injection.
Discussion
This study analyzed 49 medical malpractice lawsuits related to the complications of epidural injections in patients with chronic pain in the Korean court system. We found that the most common type of complication among the malpractice lawsuits involving an epidural injection was infection. Errors that occurred during the procedure were most commonly ruled as physician malpractice. Postprocedural errors were most commonly related to delayed management.
Several other medicolegal studies have analyzed the legal ramifications of epidural injection complications. For example, in a study of 284 claims in the American Society of Anesthesiologists (ASA) Closed Claims Project Database from 1970 to 1999, epidural injections accounted for 40% (n=114) of all claims related to chronic pain management.14 In that study, the most common etiology was nerve injury (n=28, 25%), followed by infection (n=24, 21%). More recently, a medicolegal analysis of pain medicine malpractice claims using an insurance company database from 2009 to 2016 showed 80 of 126 cases involving epidural injection.15 The most common alleged injuring event was non-sterile technique (n=17), and the most common contributing factors to injury were perceived deficits in technical skill, followed by poor clinical judgement. In an analysis of 335 medical disputes regarding pain management in Korea from 2010 to 2015, the most common type of complication was infection.16
Although our study included fewer cases in comparison to these reports, the severity of complications in our study was higher. This distinction may be due to the nature of our data, that is, lawsuit judgements versus claims. In addition, the average claim and awarded amounts in our study (average amount of claims: $359 915; average amount awarded in judgements: $170 842) were higher than those reported in lawsuit cases of orthopedic, general surgery, and coronary interventions in Korea.17–19
In our study, errors that occurred during the procedure were most likely to be ruled as medical malpractice. Inadequate sterile technique was recognized as a cause for malpractice in five of these cases. Infection, a potentially serious complication of inadequate sterile technique, has been reported in previous studies.14–16 Several practice advisories of epidural injection emphasize the importance of aseptic technique during the procedure.20 21 In addition, the ASA recommends evaluating each patient prior to the procedure in order to identify patients at the highest risk of infection.21
In three of the four cases of spinal cord infarction, triamcinolone acetonide use was recognized as a cause for malpractice. In Korea, the epidural injection of triamcinolone acetonide has been prohibited since 2013 and the epidural injections of betamethasone and hydrocortisone also have been prohibited since 2015. In 2014, the US Food and Drug Administration announced that epidural use of triamcinolone acetonide, a particulate steroid, was not recommended due to the risk of serious adverse outcomes.22 However, the US expert working group approved the use of particulate steroids for lumbar transforaminal epidural injections if patients failed to show improvement after an initial epidural injection with a non-particulate steroid.20 When pain physicians consider the epidural use of triamcinolone acetonide, they should carefully weigh the known risks and benefits of this drug.
In three of the 12 cases of needle trauma to nerve or cord or inadvertent intravascular/intrathecal injection, a lack of imaging device guidance was ruled as physician malpractice. In the safety advisory of epidural steroid injections, it was stated that all epidural injections should be performed using image guidance with a contrast medium, except in patients with contraindications to contrast.20 However, there are no legal regulations pertaining to the use of imaging guidance during epidural blocks in Korea. As result, many lawsuit judgements lack records of whether imaging guidance was used, and blind technique may not even be recognized as a malpractice. Additionally, it was recommended that cervical interlaminar epidural injection should not be performed without reviewing prior imaging studies.20 However, in our study, only 40% of the patients had preprocedural CT or MRI results, and, more specifically, only 47% of patients (7/15) undergoing cervical epidural injections had preprocedural CT or MRI results. A thorough preprocedural imaging evaluation and the use of fluoroscopy and contrast medium during the injection might increase the overall safety of the procedure.23
Finally, in the five cases of epidural hematomas, it was notable that only two were taking anticoagulants. The pain physician should always remember that epidural injections can cause epidural hematomas, even in patients who are not taking anticoagulants.
With the exception of one case, all postprocedural errors were related to delays in management, and all cases in which delayed treatment was recognized as malpractice, with one exception, led to catastrophic injuries (NAIC score ≥7). The presenting symptom of a potentially serious complication may be non-specific in nature, such as motor weakness or pain. Since these symptoms are also common transient complications after any epidural injection, pain physicians are likely to overlook serious complications. However, serious complications may not give pain physicians enough time. Delayed diagnosis and management in patients with severe complications of epidural injection have been reported to lead to irreversible neurological disorders.24 25 Therefore, if serious complications are suspected, prompt diagnostic examination and management are important. The World Institute of Pain Benelux work group guidelines recommend MRI within 3 hours in case of an unexpectedly prolonged motor or sensory block, the recurrence of motor or sensory symptoms after an initial disappearance, or a nerve block beyond the expected area.26
Obtaining an informed consent with detailed education about the risks of an epidural injection is also vital. According to a survey of North American academic regional anesthesiologists, the risk of severe complications, including paralysis and cardiac arrest, after central neuraxial block is rarely disclosed to the patients.27 However, it is the physician’s legal obligation to explain possible risks of invasive procedures and it is the patient’s right to exercise self-determination in his or her own healthcare. Moreover, thoroughly educating patients about potential complications can help them identify worrisome symptoms earlier to facilitate quicker management. Figure 3 provides a framework that may be helpful to mitigate risk associated with the events identified in this study.
Recommendations to prevent catastrophic injury after epidural injection.
This study has several limitations. First, our data lack denominator information, which precludes us from generating rates or from comparing with patients who did not develop complications. Second, our data do not include details from cases that ended in a settlement or where arbitration was not included. Third, the judicial sentences lacked detailed clinical information, such as presence of coexisting diseases. Fourth, although the opinions of consultant physicians play an important role in malpractice case decisions, a judge’s subjectivity may also affect these decisions. Fifth, we could not assess the adequacy of physician technical skill by the precedents, which is an important factor in the occurrence of major complications, as reported by Abrecht et al.15 Finally, there are differences in the medical malpractice legal judgement processes between nations, which makes these results less generalizable.
Conclusions
In conclusion, we report on the characteristics of 49 medical malpractice cases related to epidural injections in patients with chronic pain in Korea. We found that various types of complications, from the transient to the more severe, can occur during the course of an epidural injection procedure. We hope that by cataloging these cases, we can help physicians and policymakers be better informed as they contemplate quality improvement and risk mitigation strategies.
Acknowledgments
We thank Editage (www.editage.co.kr) for English language editing.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Contributors SIC: study design, statistical analysis, manuscript preparation, manuscript revision. SHS: data collection, manuscript revision. HJ: data collection, interpretation of data. JYM: manuscript revision. HJL: study design, interpretation of data, statistical analysis, manuscript preparation, manuscript revision.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The Institutional Review Board (IRB) of Seoul National University Hospital (IRB No 1910-122-1072) approved this study.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.