Abstract
Background
The purpose of this study was to determine the impact of upper extremity peripheral nerve blocks on emergency department (ED) utilization after hand and upper extremity surgery.
Methods
We reviewed all outpatient upper extremity surgeries performed in a single Midwestern state between January 2009 and June 2019 using the Indiana Network for Patient Care. These encounters were used to develop a database of patient demographics, comorbidities, concurrent procedures, and postoperative ED visit utilization data. We performed univariate, bivariate, and multivariate logistic regression analyses.
Results
Among 108 451 outpatient surgical patients, 9079 (8.4%) received blocks. Within 1 week of surgery, a greater proportion of patients who received peripheral nerve blocks (1.4%) presented to the ED than patients who did not (0.9%) (P < .001). The greatest risk was in the first 2 postoperative days (relative risk, 1.78; P < .001). Pain was the principal reason for ED utilization in the block cohort (53.6%) compared with those who did not undergo a block (35.1%) (P < .001). When controlling for comorbidities and demographics, only peripheral nerve blocks (adjusted odds ratio [OR], 1.71; P = 0.007) and preprocedural opioid use (adjusted OR, 1.43; P = .020) conferred an independently increased risk of ED utilization within the first 2 postoperative days.
Conclusions
Peripheral nerve blocks used for upper extremity surgery are associated with a higher risk of unplanned ED utilization, most likely related to rebound pain. Through proper patient education and pain management, we can minimize this unnecessary resource utilization.
Keywords: health policy, research and health outcomes, outcomes, treatment, anesthesia, specialty, pain management, surgery, epidemiology, disability, pain, diagnosis, nerve injury, nerve
Background
Given the severity of the current opioid crisis, postoperative pain management in upper extremity surgery has shifted to modalities that minimize opioid consumption. This is important because opioids may potentiate addiction, slow bowel function, increase postoperative nausea, and slow postoperative recovery. 1 Modern perioperative pain management strategies emphasize a multimodal approach, where each modality works synergistically. As part of this approach, extremity surgeons may recommend peripheral nerve blocks that selectively interrupt nociceptive signals from the surgical site. Unlike opioids, nerve blocks have minimal risk of central nervous system–mediated adverse effects and have a high therapeutic index. 2 A meta-analysis demonstrates peripheral nerve blocks are effective in decreasing analgesic consumption, improving immediate postoperative pain scores, decreasing postoperative nausea, and improving patient satisfaction. 3 These benefits have contributed to increasing use of peripheral nerve blocks over time in upper extremity surgery.4,5
The effect of peripheral nerve blocks on perioperative resource utilization, however, is less clear. It is generally believed that peripheral nerve blocks decrease health care resource utilization by obviating the need for overnight hospital stays for pain control. 6 In some subsets of patients, however, peripheral nerve blocks may actually increase resource utilization by increasing postoperative emergency department (ED) visits. 7 A meta-analysis of patients receiving a single-dose interscalene block for shoulder surgery, for example, found that pain in blocked patients is worse than controls, starting at 16 hours postoperatively. 8 This sudden and unexpected increase in pain after a peripheral nerve block administration may result in an increase in ED visits.
We have observed a higher than expected number of ED visits in the first postoperative week among patients receiving peripheral nerve blocks during outpatient upper extremity surgery. Given these anecdotal findings, we sought to determine what may be driving this increased, and potentially unnecessary, utilization of health care resources. Specifically, our goal was to assess whether there are more ED visits among patients receiving peripheral nerve blocks during outpatient upper extremity surgery compared with those who did not receive a block. We hypothesize that worsening pain after the peripheral nerve block subsides is a major driving factor in ED resource utilization in the first postoperative week.
Materials and Methods
Data Source
Using the Indiana Network for Patient Care (INPC), we built a database of patients who underwent upper extremity surgery in a single Midwestern state from January 2009 through June 2019. The database incorporated patient demographics, comorbidities, concurrent procedures, and postoperative ED encounter data. To ensure longitudinality of the data and minimize loss to follow-up, we included only patients who had an encounter in an INPC-participating institution after their surgery.
The INPC is a robust statewide health information exchange that covers more than 95% of acute care and non–office-based outpatient clinical care provided in the state of Indiana. 9 Data in the INPC are collected in real time directly from each participating organization’s proprietary health system, processed, encrypted, and stored in INPC federated data repositories according to a standardized concept dictionary.10-13 Data are obtained throughout the continuum of inpatient and outpatient health care, including electronic medical record free text and discrete data points, administrative databases, insurance claims, public health institutions, and outpatient pharmacies. Access to the INPC for research purposes is curated by the Regenstrief Institute through a team of data analysts who extract data of interest from standardized internal variable definitions, perform quality assurance, and provide a database to the research team. 14 The INPC has been used extensively for decades for high-impact health care research, 14 though only recently has gained traction in plastic surgery research. 15
Patient Sample and Variables
We identified patients using relevant upper extremity musculoskeletal Current Procedural Terminology (CPT) codes 23930 to 26989 and peripheral nerve CPT codes 64702 to 64999. Patients were included if they had upper extremity surgery in an outpatient setting and had an INPC encounter after the study period. We also recorded any additional CPT codes submitted with the same surgical encounter. Patients who received blocks were defined using concurrent CPT codes 64415 to 64418 or 64450 at the time of surgery. For each patient, we recorded demographics, including patient sex, race, median household income (based on zip code using US census data), and age at surgery. We followed the cohorts of patients who did and did not receive peripheral nerve blocks to see whether they had a postoperative ED encounter within 1 week of surgery. For patients who were evaluated in the ED, we recorded time from surgery, associated diagnosis codes and encounter text, as well as associated CPT codes. Comorbidities were recorded as present or absent on the day of surgery and defined using a standardized internal data dictionary. Variables recorded included preprocedure opioid use, recreational drug abuse, anxiety, depression, fibromyalgia, tobacco abuse, alcohol abuse, diabetes mellitus, hypertension, inflammatory arthritis, osteoarthritis, peripheral vascular disease, heart disease, lung disease, liver disease, and kidney disease. Emergency department encounter text regarding the primary reason for visit was queried for the word “pain.”
Statistics
We performed univariate analysis to describe characteristics of the population and determined the number of daily ED visits (the number of unique patients presenting to the ED on each postoperative day). We then used χ2 and Fisher exact tests to determine the bivariate relationships between categorical variables and t tests to examine differences in continuous variables. For comorbidities and other potential risk factors, we then calculated relative risk (RR) for ED visits. Multivariate logistic regression analyses used ED visits at varying postoperative time points as the dependent variable and peripheral nerve block utilization, patient demographics (age, sex, race, median household income), and comorbidities (preprocedure opioid use, anxiety, depression, fibromyalgia, tobacco abuse, alcohol abuse, hypertension, inflammatory arthritis, osteoarthritis, peripheral vascular disease, heart disease, lung disease, liver disease, kidney disease, and recreational drug use) as independent variables. We used an α of 0.05 to infer significance. All statistical analyses were performed with the Stata 16 software package (College Station, Texas).
Results
There were 108 451 patients who met inclusion criteria, of which 9079 (8.4%) received blocks and 99 372 did not (91.6%). Patients who underwent peripheral nerve block were more likely to present to the ED within 1 week of surgery (1.4 % vs 0.9%, P < .001). The risk of ED presentation was highest on postoperative day 1 and gradually decreased (Figure 1). On postoperative days 1 and 2, there was a statistically significant risk of ED utilization in patients undergoing nerve blocks, and this risk returned to baseline after 7 days.
Figure 1.
Daily emergency department visits after any upper extremity procedure.
*Statistically significant.
The primary reason for presenting to the ED within the first 2 postoperative days was pain in 37 (53.6%) patients who received a block. This was a greater proportion than the 139 (35.1%) patients who did not receive a block (RR, 1.94; 95% confidence interval [CI], 1.44-2.36; P < .001). Similarly, 53 (41.1%) patients who received blocks presented to the ED within 1 week due to pain, compared with 292 (29.4%) patients who did not receive a block (RR, 1.94; 95% CI, 1.44-2.36; P < 0.001).
Comorbidities associated with an increased risk of ED utilization during the study period are shown in Table 1. For the 80 387 (74.1%) patients for whom median household income could be estimated, there was no difference between patients who went to the ED (US $56 213) and those who did not (US $55 599, P = .228). Similarly, race was not associated with a postoperative ED encounter (P = .548). In multivariate logistic regression analysis, only peripheral nerve blocks and preprocedural opioid use were associated with increased odds of ED utilization (Table 2).
Table 1.
Prevalence of Comorbidities and Risk Factors Among Ambulatory Upper Extremity Surgical Patients.
| All patients |
ED visit |
RR (95% CI) | P value | |
|---|---|---|---|---|
| Comorbidities | No. (%) | No. (%) | ||
| Anxiety | 11 696 (10.78) | 80 (17.20) | 1.60 (1.31-1.95) | <.001 |
| Block | 9079 (8.37) | 69 (14.84) | 1.78 (1.43-2.21) | <.001 |
| Depression | 12 459 (11.49) | 88 (18.92) | 1.65 (1.37-2.00) | <.001 |
| Diabetes mellitus | 11 676 (10.77) | 77 (16.56) | 1.54 (1.26-1.89) | <.001 |
| Ethanol abuse | 1485 (1.37) | 9 (1.94) | 1.42 (0.74-2.71) | .292 |
| Fibromyalgia | 8296 (7.65) | 57 (12.26) | 1.61 (1.26-2.05) | <.001 |
| Heart disease | 34 849 (32.13) | 197 (42.37) | 1.32 (1.19-1.47) | <.001 |
| Hypertension | 30 374 (28.01) | 177 (38.06) | 1.36 (1.21-1.53) | <.001 |
| Inflammatory arthritis | 2566 (2.37) | 16 (3.44) | 1.46 (0.90-2.36) | .127 |
| Kidney disease | 7307 (6.74) | 54 (11.61) | 1.73 (1.34-2.22) | <.001 |
| Liver disease | 3370 (3.11) | 20 (4.30) | 1.39 (0.90-2.13) | .137 |
| Lung disease | 37 478 (34.56) | 187 (40.22) | 1.16 (1.04-1.30) | .010 |
| Male sex | 53 356 (49.20) | 221 (47.53) | 1.03 (0.95-1.13) | .532 |
| Osteoarthritis | 20 711 (19.10) | 124 (26.67) | 1.40 (1.20-1.63) | <.001 |
| Preprocedure opioids | 16 371 (15.10) | 110 (23.66) | 1.57 (1.33-1.85) | <.001 |
| Peripheral vascular disease | 2309 (2.13) | 16 (3.44) | 1.62 (1.00-2.63) | .050 |
| Recreational drug use | 1452 (1.34) | 12 (2.58) | 1.94 (1.10-3.39) | .020 |
| Tobacco abuse | 10 029 (9.25) | 68 (14.62) | 1.59 (1.27-1.98) | <.001 |
Note. ED visits on postoperative day 1 or 2 were included. ED = emergency department; RR = relative risk; 95% CI = 95% confidence interval.
Table 2.
Multivariate Logistic Regression With ED Visit as Outcome.
| Variable | OR (95% CI) | P value |
|---|---|---|
| Age | 1.00 (1.00-1.01) | .164 |
| Male sex | 0.90 (0.72-1.12) | .338 |
| Median income | 1.00 (1.00-1.00) | .301 |
| Race | ||
| White | Ref. | |
| Black | 0.80 (0.46-1.38) | .419 |
| Asian American | 0.62 (0.09-4.44) | .635 |
| Native Hawaiian or Other Pacific Islander | 4.16 (0.57-30.15) | .158 |
| Other | 0.79 (0.35-1.79) | .577 |
| Not specified | 1.02 (0.74-1.41) | .901 |
| Block | 1.51 (1.10-2.07) | .011 |
| Preprocedure opioids | 1.64 (1.30-2.07) | <.001 |
| Anxiety | 1.22 (0.89-1.67) | .216 |
| Depression | 1.21 (0.89-1.66) | .228 |
| Fibromyalgia | 1.23 (0.87-1.73) | .235 |
| Tobacco abuse | 1.14 (0.83-1.58) | .418 |
| Alcohol abuse | 0.91 (0.41-1.98) | .803 |
| Diabetes mellitus | 1.19 (0.86-1.64) | .296 |
| Hypertension | 1.07 (0.64-1.80) | .789 |
| Inflammatory arthritis | 0.72 (0.36-1.42) | .345 |
| Osteoarthritis | 1.05 (0.79-1.39) | .750 |
| Peripheral vascular disease | 0.99 (0.54-1.81) | .968 |
| Heart disease | 0.98 (0.59-1.64) | .949 |
| Lung disease | 0.97 (0.77-1.22) | .801 |
| Liver disease | 0.80 (0.46-1.40) | .439 |
| Kidney disease | 1.34 (0.94-1.90) | .101 |
| Recreational drug use | 1.67 (0.90-3.10) | .106 |
Note. ED visits on postoperative day 1 or 2 were the outcome of interest. The Native American or Alaskan Native race category was null. ED = emergency department; OR = adjusted odds ratio; 95% CI = 95% confidence interval; Ref. = reference.
Discussion
Peripheral nerve blocks are widely used for extremity surgery with the goal of improving pain control and decreasing the need for general anesthesia and postoperative narcotics. Blocks may also facilitate early passive movement and participation in therapy immediately following surgery. Despite these benefits, we found that peripheral nerve blocks at the time of upper extremity surgery impart a nearly 2-fold increased risk of ED utilization in the first few days after surgery. Given that ambulatory surgery is performed with the intention to avoid acute care resource utilization, an unplanned visit to the ED can be a substantial patient dissatisfier and potentially preventable use of health care resources.
Peripheral nerve blocks are not without risk,2,16-18 and rebound pain, which is a sudden increase in acute pain encountered after cessation of peripheral nerve blockade, 19 may be the primary mechanism by which peripheral nerve blocks increase ED resource utilization. Patients experience rebound pain that is more severe than the pain experienced by patients undergoing comparable surgery without a block.8,20 In a meta-analysis, Abdallah et al 8 found that a single-shot interscalene block during shoulder surgery results in pain that is worse than nonblocked patients, starting at 16 postoperative hours. Risk factors for rebound pain include younger age, 21 shorter duration of block, 22 and ineffective pain control, while a peripheral nerve block wears off.23,24 In a thematic analysis of patients receiving blocks, Henningsen et al 25 characterized patients’ experience of rebound pain as severe, concerning pain that does not respond to morphine. The sudden, severe pain is frightening for the patient and may lead him or her to seek further care. Patient understanding and expectations regarding postoperative pain control after a nerve block are insufficient, which may compound the problem. 25 This is not particularly surprising because patients are often preoccupied with the details of surgery during the preoperative period and may not internalize their perioperative education regarding postoperative pain.
There is disagreement in the literature regarding resource utilization after different modalities of peripheral nerve blockade used in surgery. Jensen et al 7 found that continuous peripheral nerve blocks are associated with increased rates of ED visits after arthroscopic rotator cuff repair (6.71% vs 4.74%, P < 0.02), and King et al 26 reported that unanticipated health care resource utilization related to continuous peripheral nerve blocks in upper extremity surgery may approach 38%. Hamilton et al, 27 however, did not find increased ED resource utilization among 2207 patients undergoing elective shoulder surgery with and without blocks at their institution, a finding corroborated by their subsequent population study of 59 644 Ontario residents. 4 Liu et al reported that among 103 476 patients undergoing outpatient arthroscopic surgery at 243 facilities in New York state, the most common reason for an unanticipated acute care encounter within 7 postoperative days (ie, inpatient or ED encounter) is musculoskeletal pain (23.8% of the 1867 acute care patient encounters). Similar to our study, these encounters most frequently occurred within the first postoperative day. 28 In a population-based study of 178 214 patients, however, McIsaac et al 29 found that peripheral nerve blocks used in knee arthroplasty reduced length of stay but had no effect on postoperative ED visits.
Our study found that peripheral nerve blockade used during upper extremity surgery is associated with an increased risk of ED utilization. This utilization occurs in the first few postoperative days and gradually returns to baseline over the first week. This seems to be primarily the result of poor pain control, likely attributable to the rebound phenomenon. These data may guide the upper extremity surgeon toward more optimal preoperative patient education regarding pain management. Repetitive efforts at education before and after surgery could enhance retention and understanding of postoperative pain control. 25
Our study has several limitations due to the data source and the retrospective nature of the study. As data are derived from an administrative database, nonreporting information bias or inaccurate data abstraction may confound the results. We attempted to limit selection bias from loss to follow-up by ensuring patients have a subsequent encounter after the study period. Furthermore, because we are using data from only 1 state, our results may not be representative of treatment and ED utilization throughout the United States. Finally, the data source could only identify patients who received a major peripheral nerve block as a separate procedure; it is possible that patients categorized as receiving no block may have received a local anesthetic injection prior to surgery. These limitations notwithstanding, our findings provide important information that surgeons can use to improve quality of care, decrease unnecessary resource utilization, and enhance patient satisfaction.
In conclusion, this study has demonstrated that peripheral nerve blocks are valuable and widely used in ambulatory upper extremity surgery, yet may represent a source of unnecessary postoperative ED resource utilization. Rebound pain is the primary reason for unplanned ED utilization in the days following surgery. Using these findings, surgeons should modify their educational efforts to prevent unnecessary resource utilization in the perioperative period.
Footnotes
Ethical Approval: This study was approved by our institutional review board.
Statement of Human and Animal Rights: This article does not contain any studies with human or animal subjects.
Statement of Informed Consent: All procedures followed were in accordance with the ethical standards of the Institutional Review Board (IRB) and with the Helsinki Declaration of 1975, as revised in 2008. No identifying patient data was accessed by the authors of this study, and therefore the IRB deemed no additional informed consent was necessary for this study.
Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article.
ORCID iDs: Scott N. Loewenstein 
https://orcid.org/0000-0002-4529-2479
Ravinder Bamba
https://orcid.org/0000-0002-6365-6686
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