The Effect of COVID-19 on Spine Surgery

Abstract

Study Design

Retrospective cohort analysis

Objective

To characterize the impact of COVID-19 on utilization of the ten most common spine procedures and percentages of outpatient procedures.

Methods

The PearlDiver national database was queried from January 2010 to April 2021 for short (<6 segments) and long segment posterior instrumented fusion (≥6 segments), posterior cervical fusion, anterior cervical decompression and fusion (ACDF), cervical laminectomy, laminoplasty, and disc arthroplasty, lumbar laminectomy, microdiscectomy, and interbody fusion. Annual procedure utilization between January 2010 through April 2021 was recorded and compared. Monthly trends were compared to January 2020. Outpatient trends were compared between 2010-2019 and 2019-2021 using segmented linear regression.

Results

Overall, all ten procedures decreased 4.3% in 2020 compared to 2019 and increased 6.3% in 2021 compared to 2019. March and April of 2020 had the largest decreases, with March 2020 decreasing 18.2% and April 2020 decreasing 51.6% compared to January 2020. Despite increasing COVID cases in January 2021, overall procedure utilization decreased only 1.8% compared to January 2020, and increased later in 2021 with April 2021 case volumes increasing by 138% compared to January 2020. Outpatient utilization of short segment posterior lumbar fusion and lumbar interbody fusion significantly increased during this time (P < .001).

Conclusion

The greatest impact on spine surgery volume from the COVID-19 pandemic occurred in March and April 2020. Spine procedure utilization was otherwise similar or increased compared to January 2020. Additionally, the volume of outpatient short segment posterior fusion and lumbar interbody fusions increased during this time period.

Introduction

In February of 2020, healthcare in the United States underwent a monumental change as the first cases of COVID-19 were recorded and a national state of emergency was declared, leading restrictions on all non-essential activities, including elective surgery.^1-4 As the initial restrictions began to expire, healthcare systems were allowed to establish guidelines and regulate procedures at their own discretion while covid numbers would continue to fluctuate, with the highest number of cases being reported in January 2021. ⁵

Compared to the previous year, the reported reduction of elective surgeries in the initial stage of the COVID-19 pandemic was 48% in the general population, ⁶ with up to 91% in a study of the Veteran Affairs (VA) system. ⁷ One large scale study assessing trends over multiple surgical specialties found that compared to case volume during the COVID-19 surge, spinal fusion and laminectomy saw a reduction of 42% and 51%, respectively, during the initial shutdown in March 2020. ⁶ However, no further characterization of spinal surgery procedure volumes during this period has been performed. Spinal surgery involves a mixture of elective and urgent surgeries and is extremely common in the United States with an estimated 1.62 million instrumented spinal procedures performed annually before 2019. ⁸ Considering that low back pain and neck-related pain are the first and fourth greatest cause of worldwide disability, the implication of these reductions for population health is significant.^9,10 While one study showed that elective surgical volume across multiple specialties returned roughly to pre-pandemic levels after several months, ⁶ many people requiring spine surgery have been lost to follow up or have delayed surgery for a long period. ¹¹ Additionally, spinal surgery patients experienced significant increases in back pain, leg pain, and physical function during the pandemic associated with increased psychological distress, ¹² underscoring the impact of the pandemic on this population.

Very few studies have attempted to define the nationwide decrease in spine surgical volume due to the pandemic, with many drawing only upon institution-specific reports.^13,14 Furthermore, we are not aware of any previous studies that have characterized the effect of COVID-19 on outpatient spine procedures. Therefore, the purpose of this study was to analyze the impact of the COVID-19 pandemic restrictions and subsequent covid case surges on spinal surgery procedure volume as well as outpatient surgical volume.

Methods

Patients were identified using the PearlDiver Mariner Database (PearlDiver Technologies, Fort Wayne, IN), which includes records from more than 90 million patients from 2010 to 2021. The database includes inpatient and outpatient records of demographics, diagnoses, and procedures from both private and public insurance. Institutional review board (IRB) approval was not required as the database is de-identified.

Using International Classification of Disease, 9th and 10th edition (ICD) and Current Procedural Terminology (CPT) codes, ten (10) of the most common spinal procedures were identified (Supplemental Table 1). These procedures included: short segment posterior fusion (<6 segments), long segment posterior fusion (≥6 segments), posterior cervical fusion, anterior cervical discectomy and fusion (ACDF), cervical laminectomy, lumbar laminectomy, microdiscectomy, cervical disc arthroplasty (CDA), cervical laminoplasty, and lumbar interbody fusion. Additionally, patients in each spinal procedure cohort were separated based on whether the procedure occurred before or after the onset of the COVID-19 pandemic. Patient demographics, including age, sex, and region in the United States, and year of procedure were collected.

The primary outcomes of this study were (1) the trends of each procedure from January of 2010 to April of 2021 (2) the monthly trends of each procedure from January of 2020 to April of 2021 and (3) the percentage of outpatient spine procedures in 2019 compared to 2020 and 2021.

The total number of monthly claims in the PearlDiver database were summated to obtain yearly claims from 2010-2021. The total number of claims for each procedure was then divided by the total yearly claims to obtain yearly volume. For monthly trends between January of 2020 and April of 2021, the number of monthly claims for each procedure was divided by total monthly claims. Outpatient procedural volumes were compared using segmented linear regression with SPSS (version 27). The year 2020 was chosen as the time point to represent the start of the COVID-19 pandemic and linear regression slopes were compared prior to (2010-2019) and after (2019-2021) that year. A P-value of <.05 was considered significant.

Results

In total, 7,539,279,865 claims were analyzed in this study, of which 1,452,477 were spine procedures. The most common age group operated on was 55-59 and the southern region of the United States contributed the largest number of cases. 53.1% of patients were female and 46.9% were male (Table 1). The most common procedure was short segment posterior fusion, followed by ACDF, and then microdiscectomy (Table 2).

Table 1.

Patient Demographics.

Demographic		N	Percent, %
Age	02 to 04	383	0
	05 to 09	1168	0
	10 to 14	8573	1
	15 to 19	13926	1
	20 to 24	13693	1
	25 to 29	24737	2
	30 to 34	51630	4
	35 to 39	82655	6
	40 to 44	115191	8
	45 to 49	149845	10
	50 to 54	181556	12
	55 to 59	198167	14
	60 to 64	192904	13
	65 to 69	170810	12
	70 to 74	175936	12
	75 to 79	96695	7
	80 to 84	17228	1
Area	Midwest	393183	27
	Northeast	237100	16
	South	619412	43
	Unknown	6520	0
	West	197284	14
Location	Clinic	54	0
	Inpatient	894021	62
	Office	3239	0
	Other	448	0
	Outpatient	595312	41
	Unknown	2362	0
Sex	Female	771532	53
	Male	680940	47
Year	2010	133477	9
	2011	132482	9
	2012	134721	9
	2013	144539	10
	2014	150186	10
	2015	143639	10
	2016	136410	9
	2017	127012	9
	2018	126515	9
	2019	138964	10
	2020	124910	9
	2021	45417	3

Table 2.

Number (N) of Each Procedure During the Entire Study Period and Percentage (%) of Each. ACDF = Anterior Cervical Discectomy and Fusion. CDA = Cervical Disc Arthroplasty.

Procedure	N	%
Short segment posterior fusion	515808	25.74
ACDF	472380	23.58
Microdiscectomy	437717	21.85
Lumbar interbody fusion	369466	18.44
Posterior cervical fusion	80257	4.01
Long segment posterior fusion	50402	2.52
CDA	26993	1.35
Cervical laminectomy	22691	1.13
Lumbar laminectomy	21320	1.06
Laminoplasty	6627	.33

Procedural Trends

Overall, there was a gradual decline in spine procedures from 2010-2017, with a gradual increase from 2017-2019, then a decrease in 2020 followed by an increase in 2021. Short segment posterior fusion was the most common procedure throughout the study period. Microdiscectomy was the second most common procedure in 2010 but had a steady decline through the study period and dropped to the fourth most common in 2021. ACDF saw a steady decline in popularity from 2010-2018, and then an increase in 2019, followed by a decrease in 2020, then a further increase in 2021. Lumbar interbody fusion saw a decline in total percentage of claims from 2010-2017, then an increase from 2017-2021. Posterior cervical fusion had a steady incline in utilization from 2010-2021, as did CDA, cervical laminoplasty, and long segment posterior fusion. Lumbar laminectomy utilization decreased over the study period. Cervical laminoplasty remained the least utilized procedure throughout the study period, but saw a steady increase in percentage of all insurance claims from 2010-2021 (Figure 1, Supplemental Table 1).

Figure 1.

Annual utilization trends, measured as cases per 100,000 insurance claims, across the top 10 most performed spine procedures across the United States from 2010-2021. ACDF = anterior cervical discectomy and fusion, CDA = cervical disc arthroplasty.

COVID-19

Compared to January of 2020, there was a significant decrease (−18.2%) in all procedures beginning in March of 2020, with the largest decrease (−51.6%) throughout the study period to follow in April of 2020. Procedure utilization progressively recovered toward the end of May 2020 (−5.1%), approximating baseline case volumes seen in January of 2020 before seeing increases in June (16.8%), wherein increases overall were sustained until December of 2020. Although there were also increasing COVID-19 case numbers in January of 2021, there was only a 1.8% decrease in total spine procedures compared to January of 2020. Later months of 2021 had an increase in total procedure volume, with April of 2021 increasing total volume by 15.3% compared to January of 2020 (Figure 2, Supplemental Table 3). Compared to 2019, 2020 had a decrease in total number of cases by 4.3%. Contrarily, 2021 had an increase in cases of 6.3% compared to 2019.

Table 3.

Total Number and Percentages of all Spine Procedures Per Month in 2020 and 2021 and the Associate Percentage (%) Increase or Decrease Compared to January of 2020.

Year	Month	Total Cases (n)	% of all Insurance Claims	% Increase or Decrease
2020	January	11914	2.0E-04	.0%
	February	11502	2.0E-04	−.6%
	March	9488	1.6E-04	−18.2%
	April	4918	1.0E-04	−51.6%
	May	9830	1.9E-04	−5.1%
	June	12820	2.3E-04	16.8%
	July	12403	2.2E-04	11.4%
	August	12151	2.3E-04	15.4%
	September	12759	2.2E-04	10.2%
	October	12891	2.1E-04	5.3%
	November	12075	2.3E-04	13.6%
	December	12547	2.3E-04	17.7%
2021	January	10481	2.0E-04	−1.8%
	February	11324	2.2E-04	9.5%
	March	13904	2.5E-04	23.6%
	April	12947	2.3E-04	15.3%

Figure 2.

The impact of COVID-19 on procedure volumes across the top 10 most performed spine procedures across the United States from January 2020 to April 2021. Procedure volume is reported on a monthly basis and as cases per 100,000 insurance claims. ACDF = anterior cervical discectomy and fusion, CDA = cervical disc arthroplasty.

Inpatient vs Outpatient

Overall, outpatient procedures increased from 2010-2021 (Figure 3). After applying segmental linear regression to determine if 2020 significantly affected the trend from previous years, outpatient short segment posterior fusion and lumbar interbody fusion both significantly increased in the era of the pandemic (Table 4). While outpatient long segment posterior lumbar fusion, posterior cervical fusion, cervical laminectomy, and total procedures all increased in percentage increase per year after 2020, these were not significant. ACDF had a similar increase to years prior. Alternatively, microdiscectomy experienced a significant reduction in the percentage increase of outpatient utilization per year after 2020.

Figure 3.

Annual percentages of the top 10 spine procedures performed in the outpatient setting across the United States from 2010 to 2021. ACDF = anterior cervical discectomy and fusion, CDA = cervical disc arthroplasty.

Table 4.

Outpatient Percentage Increases Per Year Compared Between 2010-2019 and 2019-2021. ACDF = Anterior Cervical Discectomy and Fusion. CDA = Cervical Disc Arthroplasty. *Denotes Significance.

Procedure	Outpatient Percentage Increase per Year	P-Value
Short segment posterior fusion
2010-2019	.50%
2019-2021	7.21%	<.001*
Long segment posterior fusion
2010-2019	.09%
2019-2021	2.60%	.052
Posterior cervical fusion
2010-2019	.24%
2019-2021	5.11%	.087
ACDF
2010-2019	3.44%
2019-2021	3.43%	.341
Cervical laminectomy
2010-2019	.10%
2019-2021	1.68%	.826
Lumbar laminectomy
2010-2019	.87%
2019-2021	-2.41%	.148
Microdiscectomy
2010-2019	2.39%
2019-2021	.83%	.023*
CDA
2010-2019	4.23%
2019-2021	1.77%	.385
Cervical laminoplasty
2010-2019	.54%
2019-2021	.25%	.905
Lumbar interbody fusion
2010-2019	.31%
2019-2021	9.18%	<.001*
All procedures
2010-2019	1.67%
2019-2021	2.89%	.126

Discussion

The effect of the COVID-19 pandemic on spine surgery volume was seen largely only in March of 2020 and April of 2020. Other than those 2 months, cases were similar to or increased compared to January of 2020. Our results are similar to a previous publication by Mattingly et al, which studied 11 major surgical procedure categories, including musculoskeletal, and found that surgical volume decreased across the majority of specialties in March and April of 2020. ⁶ However, surgical case volume returned to pre-pandemic levels in May of 2020 and remained steady through July of 2021.

Several other studies have attempted to define the impact of COVID-19 on orthopedic and spine surgery. Norris et al assessed effects of the pandemic on individual patients whose surgical procedures were canceled. ¹¹ In their single institution study, they found that approximately one third of patients who had previously been canceled due to COVID-19 had not rescheduled in the 8 months following reinstitution of elective procedures. They cautioned that the impact of COVID-19 on these patients was difficult to calculate and remains to be fully elucidated. Best et al attempted to quantify the economic cost of the decreased orthopedic surgical volume using national databases and concluded that the pandemic likely cost between $2.6 and $3.5 billion in net income in the United States. ¹⁵ Heckmann et al used a national inpatient database to assess trends in total hip and knee arthroplasty and found that volume decreased in March and April of 2020 and never increased to pre-pandemic levels throughout the entirety of 2020. ¹⁶

Outpatient surgical volume was found to be significantly increased in the COVID era in our study. In March of 2020, the CDC recommended that urgent elective cases be moved to outpatient settings when possible, and the Ambulatory Surgery Center Association (ASCA) released guidelines for this transition shortly afterwards. ¹⁷ Liang et al were one of the first to report on their pandemic experience out of Singapore in May of 2020 and recommended that outpatient care should be chosen if possible to decrease the inpatient hospital burden. ¹⁸ DePhillipo et al published guidelines on treating patients during the pandemic, and recommended that, when possible, surgery be performed at outpatient ambulatory surgery centers. ¹⁹ While these guidelines and studies have recommended that outpatient surgical volume should increase, the present study is the first to confirm that the COVID-19 pandemic was significantly associated with an increase in the rate of outpatient procedures, specifically short segment lumbar fusion and lumbar interbody fusion. Timing of the pandemic was not correlated with larger outpatient utilization of other procedures studied. Those procedures that were already increasing in the outpatient setting, such as ACDF and CDA, continued to increase at a rate similar to years prior. Interestingly, microdiscectomy saw a reduction in percentage increase of outpatient procedures per year, which may indicate that we are approaching an asymptote for outpatient microdiscectomy given the current volume is already above 85%.

There are several limitations to this study. First, this is a national database study and is therefore subject to human medical coding error. Second, we were limited to reporting data only within the first 4 months of 2021 due to confines of the database, so our conclusions about trends in 2021 are limited to the first 4 months of that year. Third, we did not isolate single vs multi-level procedures for many of the codes as that was not the primary aim of the study, but this may have influenced the trends observed.

In conclusion, spine surgical procedural volume decreased in March and April of 2020 due to the COVID-19 pandemic. However, case volume increased to pre-pandemic levels following these months and subsequently increased to above pre-pandemic levels. The pandemic had a significant effect on outpatient surgical volume of short segment posterior fusion and lumbar interbody fusion, which increased significantly in the COVID-19 era compared to increases in previous years.

ORCID iDs

Kevin Mertz https://orcid.org/0000-0002-9400-2247

Ethan Faye https://orcid.org/0000-0001-9376-6096

Andy Ton https://orcid.org/0000-0002-8891-0353

Raymond J. Hah https://orcid.org/0000-0001-7513-3519

Ram K. Alluri https://orcid.org/0000-0001-5919-707X