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The Patterns of Utilization of Interscalene Nerve Blocks for Total Shoulder Arthroplasty

Gabriel, Rodney A. MD; Nagrebetsky, Alexander MD, MSc; Kaye, Alan D. MD; Dutton, Richard P. MD, MBA; Urman, Richard D. MD, MBA

doi: 10.1213/ANE.0000000000001472
Regional Anesthesia and Acute Pain Medicine: Brief Report

The interscalene block (ISB) is a common adjunct to general anesthesia for total shoulder arthroplasty (TSA). The aim of the study was to report the current national demographics of the patients who are receiving ISB for TSAs. We performed a retrospective analysis of data from the National Anesthesia Clinical Outcomes Registry from 2010 to 2015. Of 28,810 cases, 42.1% received an ISB. Only 0.83% of cases received regional anesthesia as the primary anesthetic. From 2010 to 2014, there has been an increase in ISB utilization for this surgery (odds ratio, 1.21; 95% confidence interval, 1.19–1.23; P < .0001). Furthermore, we report a geographic distribution of block utilization in the United States. We have identified national patterns for the utilization of regional anesthesia for TSAs that may provide insight into future design of research studies.

From the *Department of Anesthesiology, University of California, San Diego, California; Department of Anesthesiology and Pain Management, John H. Stroger, Jr Hospital of Cook County, Chicago, Illinois; Department of Anesthesiology, Louisiana State University Health Sciences Center, New Orleans, Louisiana; §US Anesthesia Partners, Fort Lauderdale, Florida; and Department of Anesthesiology, Perioperative and Pain Medicine at Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts.

Accepted for publication May 17, 2016.

Funding: None.

Conflict of Interest: See Disclosures at the end of the article.

Reprints will not be available from the authors.

Address correspondence to Richard D. Urman, MD, MBA, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital/Harvard Medical School, 75 Francis St, Boston, MA 02115. Address e-mail to rurman@partners.org.

Total shoulder arthroplasty (TSA) is a major joint surgery, typically performed under general anesthesia with the possible addition of an interscalene nerve block (ISB).1 A recent meta-analysis demonstrated that single ISBs were associated with reduced postoperative opioid consumption, decreased postoperative nausea/vomiting, and expedited recovery room length of stay and hospital discharge.2 To date, there has been a limited number of studies performed at a national level describing the patterns of the utilization of regional anesthesia in TSAs.1 The purpose of this study was to report the current national demographics of the patients receiving ISB for TSA. We utilized the National Anesthesia Clinical Outcomes Registry (NACOR) data set to explore recent anesthesia care for TSA in the United States. With the provided data, clinicians can identify groups in which the block is underutilized and develop measures and future potential studies that can increase its utilization given the many potential benefits of this analgesic strategy.

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METHODS

We performed a retrospective analysis of the NACOR data, which houses deidentified patient information from 2010 to 2015, provided by the Anesthesia Quality Institute. NACOR is a nationwide registry that collects and organizes electronic reports on routine anesthesia care provided in the United States.3 We analyzed cases of TSA defined as records with Current Procedural Terminology code 23472 performed with or without an ISB (Current Procedural Terminology codes 64416 and 64415). We excluded records with American Society of Anesthesiologists physical status (ASA PS) VI and records with unknown type of anesthesia, ASA PS, age, or sex. Only cases that specifically stated that general anesthesia (GA) or regional anesthesia (RA) as the primary anesthetic were included in the analysis.

We gathered data for TSAs performed under GA + ISB, GA without ISB, and cases performed under RA as the primary anesthetic. Data collected included age, sex, ASA PS class, case duration (minutes), facility type, presence of an anesthesia resident or certified registered nurse anesthetist, time of day (day shift versus after hours 17:01–06:59), urban versus rural versus urban–rural zip code (based on US Census Report), presence of a board-certified anesthesiologist, and surgical volume (number of TSAs performed at that facility per year). The facility types compared in this study included university hospitals, large community hospitals (consisting of >500 beds), medium community hospitals (100–500 beds), small community hospitals (<100 beds), and “other facility types.” R Project for Statistical Computing (R version 3.1.2) was used to perform all data analysis. To report statistical trend in years, we performed a Poisson regression analysis utilizing year as a continuous variable. Results are reported as odds ratio and its 95% confidence interval. We presented the proportions of patients undergoing TSA who received an ISB in individual states as a heat map using Microsoft Excel 365 (Microsoft Inc., Redmond, WA). The heat map included data only from those states that reported ≥100 cases of TSA. Values were presented in 10% increments using the corresponding gray scale. We also presented annual data on the type of anesthesia as a bar chart.

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RESULTS

Table. C

Table. C

Figure 1

Figure 1

Figure 2

Figure 2

We identified 38,147 cases of TSA. Of these, 28,810 remained in the analysis, of which 42.0% received an ISB. Among TSA cases that received an ISB, 24% received a continuous block with a perineural catheter. Only 240 cases were performed as RA as the primary anesthetic. The analyzed cohort included data reported from 462 different health care facilities. Within the NACOR database, each year there was an observable increase in the utilization of ISB for TSA from 2010 to 2014 (odds ratio, 1.21; 95% confidence interval, 1.19–1.23; P < .0001; Figure 1). State differences among the United States in the utilization of ISB for TSAs are illustrated in Figure 2. The demographics of TSA cases included in this analysis are presented in the Table. Among all age groups, patients older than 65 years comprised the group that received the most ISBs. Females received a higher percentage of ISBs than males. Patients classified as ASA PS I to II received more ISBs than patients of higher ASA PS class. Medium-sized community hospitals performed the most blocks within NACOR. Among urban and rural environments, patients from zip codes of mixed urban/rural areas received the most ISBs. Furthermore, facilities performing <50 TSAs per year performed the most ISBs.

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DISCUSSION

The results of the present investigation demonstrated that approximately 42% of patients undergoing TSA received an ISB and <1% were performed purely under RA. Less than half of patients undergoing TSA received an ISB in this study, despite evidence of faster recovery and improved patient satisfaction associated with this nerve block.4–6 In any case, the rate of utilization is increasing every year. Possible explanations for a relatively lower percentage of ISB utilization include concerns related to known complications, lack of available anesthesiologists skilled in this subspecialty, provider preference, or lack of technical resources or appropriate workflows.7 Barriers to increasing the utilization of this regional anesthetic in practice are multifactorial; however, we were able to describe case, provider, and facility characteristics that may influence its utilization. The data provide a framework for future studies that would aim to identify patient and case characteristics making patients less likely to receive a nerve block. It is important to identify these associations to better understand the barriers that may influence RA volume. Health care facilities performing TSAs may use our data to view their current RA practice and benchmark it against national practices. Furthermore, availability of resources for RA likely plays a role in ISB utilization for TSAs. Having more experienced anesthesiologists and available regionalists at certain times of the day could increase individual facility rates for ISB use. As more data are compiled, it will be important to examine how national trends shift in the future. This study may serve as a baseline for assessment of changes in anesthetic approaches to TSA over time.

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DISCLOSURE

Name: Rodney A. Gabriel, MD.

Contribution: This author helped design the study, conduct the study, collect the data, analyze the data, and prepare the manuscript.

Conflicts of Interest: This author declared no conflicts of interest.

Name: Alexander Nagrebetsky, MD, MSc.

Contribution: This author helped design the study, conduct the study, analyze the data, and prepare the manuscript.

Conflicts of Interest: This author declared no conflicts of interest.

Name: Alan D. Kaye, MD.

Contribution: This author helped design the study and prepare the manuscript.

Conflicts of Interest: This author declared no conflicts of interest.

Name: Richard P. Dutton, MD, MBA.

Contribution: This author helped design the study and prepare the manuscript.

Conflicts of Interest: This author declared no conflicts of interest.

Name: Richard D. Urman, MD, MBA.

Contribution: This author helped design the study and prepare the manuscript.

Conflicts of Interest: Member of the Data Use Committee, Anesthesia Quality Institute.

This manuscript was handled by: Richard Brull, MD, FRCPC.

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REFERENCES

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