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. 2021 Nov 16;52(1):22–35. doi: 10.1007/s00595-021-02406-2

The impact of COVID-19 on surgical procedures in Japan: analysis of data from the National Clinical Database

Norihiko Ikeda 1,2,, Hiroyuki Yamamoto 3, Akinobu Taketomi 1,4, Taizo Hibi 1,5, Minoru Ono 1,6, Naoki Niikura 7, Iwao Sugitani 8, Urara Isozumi 3, Hiroaki Miyata 3, Hiroaki Nagano 1,9, Michiaki Unno 10, Yuko Kitagawa 1,11, Masaki Mori 1,12,13
PMCID: PMC8592826  PMID: 34783905

Abstract

Background and purpose

The spread of COVID-19 has restricted the delivery of standard medical care to surgical patients dramatically. Surgical triage is performed by considering the type of disease, its severity, the urgency for surgery, and the condition of the patient, in addition to the scale of infectious outbreaks in the region. The purpose of this study was to evaluate the impact of the COVID-19 pandemic on the number of surgical procedures performed and whether the effects were more prominent during certain periods of widespread infection and in the affected regions.

Methods

We selected 20 of the most common procedures from each surgical field and compared the weekly numbers of each operation performed in 2020 with the respective numbers in 2018 and 2019, as recorded in the National Clinical Database (NCD). The surgical status during the COVID-19 pandemic as well as the relationship between surgical volume and the degree of regional infection were analyzed extensively.

Results

The rate of decline in surgery was at most 10–15%. Although the numbers of most oncological and cardiovascular procedures decreased in 2020, there was no significant change in the numbers of pancreaticoduodenectomy and aortic replacement procedures performed in the same period.

Conclusion

The numbers of most surgical procedures decreased in 2020 as a result of the COVID-19 pandemic; however, the precise impact of surgical triage on decrease in detection of disease warrants further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00595-021-02406-2.

Keywords: COVID-19, Surgical triage, National clinical database

Introduction

The rapid spread of the novel coronavirus disease 2019 (COVID-19), which first appeared in Wuhan, China, evolved into a global pandemic, disrupting all aspects of life across the world, including Japan [1, 2]. The number of infected people has increased dramatically since the first case was reported in Japan on January 15, 2020; however, a comprehensive strategy for the diagnosis and treatment of COVID-19 is yet to be established. Although approximately 80% of patients who acquire COVID-19 recover, there is a high risk of COVID-19 infection resulting in severe disease or death, especially among elderly people with comorbidities such as chronic obstructive pulmonary disease, chronic kidney disease, diabetes, hypertension, cerebrocardiovascular disease, obesity, and people with malignant tumors [3].

Medical resources such as labor, space, and equipment often needed to be reallocated to manage the influx of COVID-19 patients and this restricted the ability to deliver standard medical care to patients with other diseases. However, surgical care should not be interrupted even under such circumstances, as surgeons have multiple responsibilities to continue surgical treatment even in difficult situations such as a pandemic. Nevertheless, surgeons must select which surgical procedures to perform with careful consideration of many factors, ensuring the management of in-hospital surgical systems and preventing nosocomial infections, especially among perioperative patients. Surgical triage should be performed under comprehensive consideration of the type of disease, its severity, the urgency of surgery, and the condition of the patient, as well as the scale of infectious outbreak in the region and the status of medical care provision in the facility [4].

To manage these conditions, the Japan Surgical Society’s “Guidelines for performing surgical triage during the COVID-19 pandemic”, has classified the status of the medical care system into a ‘stable period’ and a ‘restricted period’ [5]. Diseases or indications for surgery have been divided into three levels:

(A) A disease or condition that is nonfatal or does not require urgent medical intervention.

(B) A disease or condition unlikely to be fatal, but is at risk of becoming severe and being potentially fatal.

(C) A disease or condition that may be fatal in a few days or months without any surgical intervention.

If surgical triage is performed with reference to these guidelines, the number of operations should fluctuate and act as an indicator of the impact of COVID-19 infection on surgical treatment. However, given that little is known about the exact number of operations that were cancelled or postponed and which specialties were most affected during this period in Japan, the current survey of major surgical procedures performed in 2020 represents an overview of surgical practices during the COVID-19 pandemic. It will be an important resource for creating a system to allow continuity of surgical treatment in the event of a disaster, such as the outbreak of a new highly transmissible infection.

Method

The members of the novel coronavirus disease 2019 outbreak committee of the Japan Surgical Society selected 20 of the most common surgical procedures performed in each surgical field.

  • Digestive surgery: gastrectomy (including distal gastrectomy, pylorus-preserving gastrectomy and segmental gastrectomy), low anterior resection of the rectum, hepatectomy of one section or more (excluding left lateral section), pancreatoduodenectomy, appendectomy, and cholecystectomy

  • Cardiovascular surgery: valve replacement + valve plasty, ascending aorta replacement + aortic arch replacement, coronary artery bypass grafting (CABG), abdominal aorta replacement (below renal artery), ventricular septal defect closure

  • General thoracic surgery: lobectomy (+ mediastinal lymph node dissection), resection of a mediastinal tumor

  • Breast surgery: total mastectomy, breast-conserving surgery, sentinel node biopsy

  • Endocrine surgery: thyroidectomy, parathyroidectomy

  • Pediatric surgery (under 16 years of age): inguinal hernia repair, appendectomy

For this study, lobectomy and thoracic aorta replacement refer to pulmonary lobectomy and ascending aorta replacement + aortic arch replacement, respectively.

The primary outcome measure of this study was to identify the impact of the COVID-19 pandemic on surgical care, including any decrease in the number of surgeries. This was analyzed by extracting essential data from the National Clinical Database (NCD). The NCD is a nationwide web-based surgical patient registration system, which enables the collection of data on all surgical procedures performed in Japan, in addition to perioperative factors. More than 14,340,000 procedures, accounting for more than 90% of all surgeries performed in Japan during this period, have been registered by approximately 5,000 hospitals [6, 7]. The NCD constructed software for an Internet-based data collection system and data managers in participating hospitals were responsible for forwarding their data to the NCD office [7]. Using the NCD to investigate all surgeries performed in 2020 is an ideal means to evaluate this extraordinary change in Japanese surgical practices caused by the spread of COVID-19. The total number and change in numbers of each procedure performed in 2020 were analyzed weekly (STATA 17, STATA Corp., TX, USA) and compared with the status in 2018 and 2019.

Some concerns were raised about the possibility of a stronger impact on surgery during certain periods of widespread infection or in areas with high numbers of infected people. The following two settings were used to clarify such speculation.

Period of COVID-19 pandemic

The first and second waves of the COVID-19 pandemic in Japan were recognized as periods, or phases, when the spread of infection was remarkable. There is no fixed definition for this specific period in the pandemic; therefore, we determined these periods for our study based on changes in the number of infected people nationwide and the objective public view.

The first pandemic wave was stipulated as being from February 26 to May 26, 2020, because the government decided on the basic policy for infection control on February 25 [8] and the state of emergency was lifted nationwide on May 25 [9]. The second wave was from July 1 to September 29, 2020, as the government called for thorough countermeasures to address the increase in the number of infected people on June 30 [10]. The dramatic increase in the number of newly infected people as of September 30 was also the focus of discussion during the Tokyo Metropolitan Coronavirus Infection Monitoring Conference [11].

Classification of prefectures according to the degree of infection

The cumulative number of infected people per population of prefectures (as of the end of 2020) [12] was used as an index of the degree of infection. Based on this value, the degree of infection in prefectures was classified into three groups: high, medium and low.

  • High group: Aichi, Chiba, Fukuoka, Hokkaido, Hyogo, Kanagawa, Kyoto, Nara, Okinawa, Osaka, Saitama, and Tokyo (12 prefectures)

  • Medium group: Fukushima, Gifu, Gunma, Hiroshima, Ibaragi, Ishikawa, Kagoshima, Kochi, Kumamoto, Mie, Miyagi, Miyazaki, Nagano, Oita, Okayama, Saga, Shiga, Shizuoka, Tochigi, Toyama, Yamanashi, and Wakayama (22 prefectures)

  • Low group: Akita, Aomori, Ehime, Fukui, Iwate, Kagawa, Nagasaki, Niigata, Shimane, Tokushima, Tottori, Yamagata and Yamaguchi (13 prefectures)

We compared the total number of each of the 20 surgical procedures performed in 2019 and 2020 and investigated whether there was a significant decrease in the number of these operations performed in the first and second wave periods in 2020, compared with the same period in 2019.

We also analyzed whether the numbers decreased more significantly in prefectures with higher infection levels throughout the year or during the first and second waves compared with other regions. The two-way repeated-measures analysis of variance (two-way RMANOVA) was used for statistical analysis. The level of statistical significance was set at p < 0.05.

Results

Table 1 summarizes the status of surgery for the 20 procedures. A total of 530,701 operations were scheduled between January 1 and December 31, 2020, which corresponded to 95.0% and 97.5% of the total number of surgeries performed in 2018 and 2019, respectively. Cases of unknown age and gender were excluded from the analysis. Figure 1 shows the weekly number of each of the 20 procedures in 2020 as line graphs and the status in 2018 and 2019 for comparison.

Table 1.

Number of operations performed for each procedure in 2020 vs. 2018 and 2019

Procedure Number of operations (2018) Number of operations (2019) Number of operations (2020) vs. 2018 vs. 2019
Gastrectomy 37,733 37,173 32,723 86.7% 88.0%
Low anterior resection 22,099 22,763 21,506 97.3% 94.5%
Hepatectomy 6734 7019 6707 99.6% 95.6%
Pancreaticoduodenectomy 11,774 11,963 12,074 102.5% 100.9%
Appendectomy 57,742 59,152 60,094 104.1% 101.6%
Cholecystectomy 132,766 133,441 127,621 96.1% 95.6%
Valve replacement + valve plasty 21,938 21,887 20,355 92.8% 93.0%
Ascending aorta replacement + aortic arch replacement 11,170 11,375 11,186 100.1% 98.3%
Coronary artery bypass grafting 19,704 19,109 17,452 88.6% 91.3%
Abdominal aorta replacement 6985 6624 6249 89.5% 94.3%
Ventricular septal defect closure 1791 1698 1681 93.9% 99.0%
Lobectomy 31,677 33,815 31,174 98.4% 92.2%
Resection of mediastinal tumor 6011 6575 6152 102.3% 93.6%
Total mastectomy 48,276 51,435 50,283 104.2% 97.8%
Breast-conserving surgery 40,003 42,475 39,495 98.7% 93.0%
Sentinel node biopsy 45,501 49,728 48,848 107.4% 98.2%
Thyroidectomy 15,262 15,405 13,449 88.1% 87.3%
Parathyroidectomy 1824 1879 1827 100.2% 97.2%
Inguinal hernia repair (under age 16) 17,171 16,736 14,232 82.9% 85.0%
Appendectomy (under age 16) 8269 8150 7593 91.8% 93.2%
Total 544,430 558,402 530,701 97.5% 95.0%

Fig. 1.

Fig. 1

Fig. 1

Fig. 1

Fig. 1

Trends in the weekly volume of each procedure (2018–2020) Shaded areas show the periods of the first and second pandemic waves (February 26-May 26, and July 1-September 29, respectively)

Table 2 compares the total numbers of each of the 20 surgical procedures during the first and second waves of the COVID-19 pandemic and outlines the differences in surgical situations among the three prefectural groups according to the degree of infection. Detailed results are described below.

Table 2.

Number of surgeries performed in the pandemic period and regional infection level classifications

Procedure Period Infection level 2018 2019 2020 vs 2018 vs 2019 p value vs 2019 p value high vs medium + low
Gastrectomy 1st pandemic period High 5176 5166 4676 90.3% 90.5%
Medium 2795 2597 2586 92.5% 99.6%
Low 1177 1215 1223 103.9% 100.7%
Subtotal 9148 8978 8485 92.8% 94.5% 0.084 0.087
2nd pandemic period High 5222 5255 4018 76.9% 76.5%
Medium 2848 2836 2316 81.3% 81.7%
Low 1321 1244 1012 76.6% 81.4%
Subtotal 9391 9335 7346 78.2% 78.7%  < 0.001 0.122
Yearly Total 37,733 37,173 32,723 86.7% 88.0%  < 0.001 0.046
Low anterior resection 1st pandemic period High 3193 3404 3255 101.9% 95.6%
Medium 1659 1661 1669 100.6% 100.5%
Low 630 715 668 106.0% 93.4%
Subtotal 5482 5780 5592 102.0% 96.7%  < 0.001  < 0.001
2nd pandemic period High 3152 3341 2941 93.3% 88.0%
Medium 1617 1558 1428 88.3% 91.7%
Low 662 643 567 85.6% 88.2%
Subtotal 5431 5542 4936 90.9% 89.1% 0.090 0.003
Yearly Total 22,099 22,763 21,506 97.3% 94.5%  < 0.001  < 0.001
Hepatectomy 1st pandemic period High 999 1017 978 97.9% 96.2%
Medium 494 544 544 110.1% 100.0%
Low 201 184 213 106.0% 115.8%
Subtotal 1694 1745 1735 102.4% 99.4% 0.886 0.333
2nd pandemic period High 970 1083 950 97.9% 87.7%
Medium 486 568 474 97.5% 83.5%
Low 171 169 182 106.4% 107.7%
Subtotal 1627 1820 1606 98.7% 88.2% 0.018 0.543
Yearly Total 6734 7019 6707 99.6% 95.6% 0.034 0.520
Pancreaticoduodenectomy 1st pandemic period High 1724 1758 1783 103.4% 101.4%
Medium 897 871 919 102.5% 105.5%
Low 349 361 342 98.0% 94.7%
Subtotal 2970 2990 3044 102.5% 101.8% 0.612 0.970
2nd pandemic period High 1685 1791 1748 103.7% 97.6%
Medium 892 801 842 94.4% 105.1%
Low 341 347 339 99.4% 97.7%
Subtotal 2918 2939 2929 100.4% 99.7% 0.935 0.536
Yearly Total 11,774 11,963 12,074 102.5% 100.9% 0.627 0.429
Appendectomy 1st pandemic period High 8609 8753 8268 96.0% 94.5%
Medium 3958 4113 4081 103.1% 99.2%
Low 1556 1538 1474 94.7% 95.8%
Subtotal 14,123 14,404 13,823 97.9% 96.0% 0.038 0.155
2nd pandemic period High 9854 9916 10,325 104.8% 104.1%
Medium 4704 4874 4920 104.6% 100.9%
Low 1828 1694 1801 98.5% 106.3%
Subtotal 16,386 16,484 17,046 104.0% 103.4% 0.037 0.326
Yearly Total 57,742 59,152 60,094 104.1% 101.6% 0.080 0.808
Cholecystectomy 1st pandemic period High 17,991 18,290 15,688 87.2% 85.8%
Medium 9705 9984 9012 92.9% 90.3%
Low 4036 3971 3699 91.7% 93.2%
Subtotal 31,732 32,245 28,399 89.5% 88.1% 0.001 0.201
2nd pandemic period High 18,806 19,373 18,778 99.9% 96.9%
Medium 10,381 10,526 10,276 99.0% 97.6%
Low 4223 4029 3975 94.1% 98.7%
Subtotal 33,410 33,928 33,029 98.9% 97.4% 0.300 0.734
Yearly Total 132,766 133,441 127,621 96.1% 95.6% 0.001 0.337
Valve replacement + valve plasty 1st pandemic period High 3454 3547 3019 87.4% 85.1%
Medium 1553 1557 1418 91.3% 91.1%
Low 581 548 501 86.2% 91.4%
Subtotal 5588 5652 4938 88.4% 87.4% 0.001 0.066
2nd pandemic period High 3353 3370 3085 92.0% 91.5%
Medium 1487 1496 1315 88.4% 87.9%
Low 525 505 532 101.3% 105.3%
Subtotal 5365 5371 4932 91.9% 91.8% 0.068 0.573
Yearly Total 21,938 21,887 20,355 92.8% 93.0%  < 0.001 0.047
Ascending aorta replacement + aortic arch replacement 1st pandemic period High 1859 1833 1633 87.8% 89.1%
Medium 747 786 733 98.1% 93.3%
Low 283 298 234 82.7% 78.5%
Subtotal 2889 2917 2600 90.0% 89.1% 0.008 0.453
2nd pandemic period High 1468 1532 1538 104.8% 100.4%
Medium 597 616 663 111.1% 107.6%
Low 213 218 196 92.0% 89.9%
Subtotal 2278 2366 2397 105.2% 101.3% 0.745 0.842
Yearly Total 11,170 11,375 11,186 100.1% 98.3% 0.391 0.595
Coronary artery bypass grafting 1st pandemic period High 3253 3145 2738 84.2% 87.1%
Medium 1449 1362 1206 83.2% 88.5%
Low 529 495 422 79.8% 85.3%
Subtotal 5231 5002 4366 83.5% 87.3%  < 0.001 0.178
2nd pandemic period High 2924 2919 2524 86.3% 86.5%
Medium 1252 1262 1043 83.3% 82.6%
Low 420 435 415 98.8% 95.4%
Subtotal 4596 4616 3982 86.6% 86.3%  < 0.001 0.311
Yearly Total 19,704 19,109 17,452 88.6% 91.3%  < 0.001 0.196
Abdominal aorta replacement 1st pandemic period High 943 847 759 80.5% 89.6%
Medium 577 539 535 92.7% 99.3%
Low 166 153 141 84.9% 92.2%
Subtotal 1686 1539 1435 85.1% 93.2% 0.133 0.293
2nd pandemic period High 1022 979 868 84.9% 88.7%
Medium 601 594 482 80.2% 81.1%
Low 178 156 180 101.1% 115.4%
Subtotal 1801 1729 1530 85.0% 88.5% 0.006 0.730
Yearly Total 6985 6624 6249 89.5% 94.3% 0.003 0.892
Ventricular septal defect closure 1st pandemic period High 282 253 252 89.4% 99.6%
Medium 121 123 116 95.9% 94.3%
Low 45 41 32 71.1% 78.0%
Subtotal 448 417 400 89.3% 95.9% 0.504 0.555
2nd pandemic period High 303 306 271 89.4% 88.6%
Medium 118 119 132 111.9% 110.9%
Low 46 27 34 73.9% 125.9%
Subtotal 467 452 437 93.6% 96.7% 0.673 0.130
yearly Total 1791 1698 1681 93.9% 99.0% 0.774 0.353
Lobectomy 1st pandemic period High 4390 4697 4503 102.6% 95.9%
Medium 2049 2235 2214 108.1% 99.1%
Low 867 955 978 112.8% 102.4%
Subtotal 7306 7887 7695 105.3% 97.6%  < 0.001  < 0.001
2nd pandemic period High 4600 4998 4173 90.7% 83.5%
Medium 2363 2476 1914 81.0% 77.3%
Low 973 1003 895 92.0% 89.2%
Subtotal 7936 8477 6982 88.0% 82.4%  < 0.001  < 0.001
yearly Total 31,677 33,815 31,174 98.4% 92.2%  < 0.001  < 0.001
Resection of mediastinal tumor 1st pandemic period High 839 956 872 103.9% 91.2%
Medium 412 419 443 107.5% 105.7%
Low 157 147 147 93.6% 100.0%
Subtotal 1408 1522 1462 103.8% 96.1% 0.528 0.260
2nd pandemic period High 984 1055 919 93.4% 87.1%
Medium 482 471 430 89.2% 91.3%
Low 160 183 156 97.5% 85.2%
Subtotal 1626 1709 1505 92.6% 88.1% 0.014 0.386
Yearly Total 6011 6575 6152 102.3% 93.6% 0.007 0.109
Total mastectomy 1st pandemic period High 6679 7415 7609 113.9% 102.6%
Medium 3061 3555 3582 117.0% 100.8%
Low 1123 1288 1420 126.4% 110.2%
Subtotal 10,863 12,258 12,611 116.1% 102.9% 0.270 0.912
2nd pandemic period High 7581 7899 7252 95.7% 91.8%
Medium 3688 3648 3570 96.8% 97.9%
Low 1375 1389 1363 99.1% 98.1%
Subtotal 12,644 12,936 12,185 96.4% 94.2% 0.245 0.398
Yearly Total 48,276 51,435 50,283 104.2% 97.8% 0.195 0.325
Breast-conserving surgery 1st pandemic period High 5766 6233 6191 107.4% 99.3%
Medium 2708 2874 2863 105.7% 99.6%
Low 1024 1064 1078 105.3% 101.3%
Subtotal 9498 10,171 10,132 106.7% 99.6% 0.903 0.888
2nd pandemic period High 5940 6313 5428 91.4% 86.0%
Medium 2797 2916 2492 89.1% 85.5%
Low 1053 1041 982 93.3% 94.3%
Subtotal 9790 10,270 8902 90.9% 86.7% 0.017 0.457
Yearly Total 40,003 42,475 39,495 98.7% 93.0%  < 0.001 0.259
Sentinel node biopsy 1st pandemic period High 6675 7481 7922 118.7% 105.9%
Medium 2905 3325 3478 119.7% 104.6%
Low 930 1091 1234 132.7% 113.1%
Subtotal 10,510 11,897 12,634 120.2% 106.2% 0.034 0.663
2nd pandemic period High 7270 7821 7050 97.0% 90.1%
Medium 3142 3290 3034 96.6% 92.2%
Low 1034 1058 1102 106.6% 104.2%
Subtotal 11,446 12,169 11,186 97.7% 91.9% 0.142 0.396
Yearly Total 45,501 49,728 48,848 107.4% 98.2% 0.339 0.336
Thyroidectomy 1st pandemic period High 2267 2311 1887 83.2% 81.7%
Medium 1084 1192 1087 100.3% 91.2%
Low 343 299 271 79.0% 90.6%
Subtotal 3694 3802 3245 87.8% 85.3%  < 0.001 0.010
2nd pandemic period High 2353 2481 1911 81.2% 77.0%
Medium 1218 1228 1170 96.1% 95.3%
Low 347 318 281 81.0% 88.4%
Subtotal 3918 4027 3362 85.8% 83.5%  < 0.001  < 0.001
Yearly Total 15,262 15,405 13,449 88.1% 87.3%  < 0.001  < 0.001
Parathyroidectomy 1st pandemic period High 270 273 222 82.2% 81.3%
Medium 144 154 143 99.3% 92.9%
Low 46 39 38 82.6% 97.4%
Subtotal 460 466 403 87.6% 86.5% 0.095 0.292
2nd pandemic period High 272 301 262 96.3% 87.0%
Medium 125 158 145 116.0% 91.8%
Low 45 29 30 66.7% 103.4%
Subtotal 442 488 437 98.9% 89.5% 0.204 0.496
Yearly Total 1824 1879 1827 100.2% 97.2% 0.477 0.241
Inguinal hernia repair (under age 16) 1st pandemic period High 2426 2409 1801 74.2% 74.8%
Medium 1307 1269 1059 81.0% 83.5%
Low 430 448 361 84.0% 80.6%
Subtotal 4163 4126 3221 77.4% 78.1%  < 0.001 0.145
2nd pandemic period High 2818 2718 2252 79.9% 82.9%
Medium 1494 1405 1225 82.0% 87.2%
Low 616 512 441 71.6% 86.1%
Subtotal 4928 4635 3918 79.5% 84.5% 0.002 0.301
Yearly Total 17,171 16,736 14,232 82.9% 85.0%  < 0.001 0.045
Appendectomy (under age 16) 1st pandemic period High 1192 1155 1066 89.4% 92.3%
Medium 602 582 557 92.5% 95.7%
Low 223 243 187 83.9% 77.0%
Subtotal 2017 1980 1810 89.7% 91.4% 0.009 0.895
2nd pandemic period High 1391 1379 1291 92.8% 93.6%
Medium 732 719 614 83.9% 85.4%
Low 295 261 270 91.5% 103.4% 0.936
Subtotal 2418 2359 2175 90.0% 92.2% 0.076 0.936
Yearly Total 8269 8150 7593 91.8% 93.2%  < 0.001 0.679

Comparison between 2019 and 2020

Digestive surgery

We did not identify a significant change in the number of pancreaticoduodenectomies or appendectomies from 2019; however, the numbers of gastrectomy, low anterior resection of the rectum, hepatectomy, and cholecystectomy, decreased significantly. Among these, the rate of decline in gastrectomies and low anterior resections of the rectum was more prominent in prefectures with high infection levels than in those with moderate or low infection levels. (p < 0.001).

Cardiovascular surgery

The numbers of thoracic aorta replacement and ventricular septal defect closure procedures did not change significantly from 2019, but the numbers of other procedures, such as valve replacement + valve plasty, CABG and abdominal aorta replacement, decreased significantly (p < 0.001, p < 0.001, p = 0.003, respectively). The rate of decline of CABG and abdominal aorta replacements did not differ by region.

General thoracic surgery

The numbers of lobectomy and resection of mediastinal tumors in 2020 decreased from the previous year (p < 0.001, both) and the rate of decrease in lobectomies was more significant in prefectures with high infection levels (p < 0.001).

Breast surgery and endocrine surgery

The operative status for total mastectomy and parathyroidectomy was not significantly different from that in 2019. The number of breast-conserving surgeries and thyroidectomies was significantly lower in 2020 (p < 0.001, both) and the rate of decrease for the latter was more prominent in prefectures with high infection levels.

Pediatric surgery

The numbers of inguinal hernia repairs and appendectomies were significantly lower in 2020. The rate of decrease in inguinal hernia repairs performed was more pronounced in prefectures with high infection levels, but the rate of decrease in the numbers of appendectomies performed did not differ by region.

Period of COVID-19 pandemic

There was a marked decrease in the numbers of low anterior resection of the rectum, lobectomy of the lung (Fig. 2) and thyroidectomy in prefectures with high rates of infection compared with the numbers in other areas during the first and second waves of the pandemic in 2020. On the other hand, no such regional differences were evident for pancreaticoduodenectomy, appendectomy, thoracic aorta replacement (Fig. 2), VSD closure, total mastectomy, or parathyroidectomy. (Supplemental Fig. 1 shows representative graphs for the other 15 procedures).

Fig. 2.

Fig. 2

Weekly volume of five procedures according to the three groups (high, medium, low) of regional infection level. Shaded areas show the periods of the first and second pandemic waves (February 26-May 26, and July 1-September 29, respectively)

Discussion

We conducted this study to establish the impact of the COVID-19 pandemic on the number of surgical procedures performed in Japan during this period by comparing the total number of operations for 20 representative surgical procedures in 2020 with that of those in the 2 pre-pandemic years. We also evaluated whether the effects of COVID-19 were more serious during certain periods and in regions where the infection was more widespread.

Although the numbers of most operative procedures decreased in 2020, we were able to identify differences in the rate of decline in the numbers for each procedure and evaluate the impact of the scale of infection on surgical treatment. Since the purpose of this study was to provide an overview of surgical procedures in 2020, we did not investigate details such as preoperative disease status, stage of malignancy, or postoperative course. In addition to surgical triage, the decrease in the numbers of surgeries performed may be attributable to multiple factors, such as fewer new patients and postponement of examinations, which will also be the subject of our next study.

Ultimately, surgery should be performed as usual and without delay for symptomatic advanced cancer, although non-aggressive cancers differentiated by improved diagnostic methods may be postponed until the pandemic subsides [4, 13]. Moreover, for high-risk patients with multiple comorbidities, postponing surgery may be necessary to avoid the risk of postoperative infection.

According to a large-scale surgical triage survey of 359 hospitals in 71 countries, including Japan, 73% (approximately 1.4 million) of operations, including upper and lower gastrointestinal, hepatobiliary, urological, head and neck, gynecological, plastic, orthopedic, and obstetric operations, which were scheduled to take place over a 12-week period, from late March 2020, were cancelled or postponed. Among these, approximately 98,000 were procedures for cancer (30%) and 1,253,000 were procedures for benign diseases (84%) [14]. An international, prospective, cohort study including 20,006 patients from 466 hospitals in 61 countries was conducted to reveal the effect of COVID-19 pandemic lockdowns on elective cancer surgery. Of eligible patients awaiting surgery, 0.6% had their surgery postponed during light restrictions, 5.5% in moderate lockdowns, and 15.0% in full lockdowns [15]. We want to entrust further analysis of clinical factors, disease severity, stage, and histological type of malignant tumors and postoperative course to the research in each specialized surgical field in the near future.

Although our study was limited to typical surgical procedures, the results showed that the rate of decline for surgery was no more than 10–15%. It is possible that since Japan had far fewer patients with COVID-19 infection than most Western countries, surgeons could schedule high-priority operations even during the pandemic when the number of COVID-19 cases was growing. Okuno used the Diagnosis Procedure Combination (DPC) data from the Quality Indicator/Improvement Project (QIP) database to compare surgical volume between the two periods of July 2018–March 2020 and April–June 2020. That analysis revealed that the decline in oncological procedures for gastrointestinal, hepato-pancreato-biliary, lung, breast, and genitourinary cancer was not significant, even though the numbers were lower than for the same period in the previous year [16]. Miyawaki compared the number of surgeries across specialties in weeks 2 to 9 versus weeks 10 to 17 in 2020 using the de-identified hospital administrative database from Japanese acute-care hospitals. The rates of decline in cardiovascular surgery and gastrointestinal or hepato-pancreato-biliary system were 9.9% and 9.5%, respectively; however, the number of breast operations did not decrease significantly [17]. There are variations in the trends of the affected number of surgical procedures based on the region and time period [18]. Our study shows that the numbers of low anterior resections of the rectum, CABG, lung lobectomies, thyroidectomies, and inguinal hernia repairs were significantly lower during the first and second COVID-19 pandemic waves. There are various reasons for each disease, such as surgical triage, fewer new patients, and implementation of alternative treatments.

Patients with potentially curable pancreatic carcinoma, pancreatic cystic lesions with confirmed high-grade dysplasia, duodenal cancer, ampullary cancer, as well as curable hepatocellular carcinoma (HCC), and cholangiocarcinoma should undergo surgical resection even during a pandemic [19]. Our results showed that the number of pancreaticoduodenectomies did not decline in 2020, in accordance with consensus statements supported by seven international pancreatic associations [20]. However, other surgical procedures for gastric, colon, liver, lung, and breast cancers, decreased significantly. Another possible cause, along with the impact of triage, may be the 30% decrease in the number of people being screened for cancer in Japan in 2020 [21]. For hepatic malignancies, such as HCC, treating practitioners may select alternative procedures, including radiofrequency ablation and transarterial chemoembolization as locoregional therapies, and molecular targeting drugs for the advanced disease instead of resection for some patients [22].

During the COVID-19 pandemic era, opportunities for cancer screening by upper gastrointestinal endoscopy (UGI) or colonoscopy may have decreased because it is an aerosol-generating procedure [23]. In fact, it was reported that the total volume of endoscopic procedures decreased by 44% during this time [24]. The decline in the number of gastrectomies or anterior resections of the rectum may be related to the decrease in these endoscopic screening procedures.

However, early cancer that is left unscreened might be detected as advanced cancer in the future. Further detailed studies for each cancer could help to verify whether there is a stage shift in surgical cases in the next few years. The significant decrease in the number of cholecystectomies in the present study is in line with an international survey including 14 countries [25], where the majority (72%) of hepato-pancreato-biliary surgeons reported an “alarming decrease” in the number of cholecystectomies during the pandemic. An increase in non-surgical treatment for acute cholecystitis was also reported by multicenter studies from the U.K. and Spain [26, 27], although a multisocietary position statement concluded that laparoscopic cholecystectomy remains the treatment of choice for acute cholecystitis even during the COVID-19 pandemic [28]. Whether the choice of non-surgical treatment for complicated gallstone disease negatively impacted the outcomes of patients warrants further investigation.

Cardiovascular surgery frequently requires transfer of the patient to an intensive care unit and ventilatory support in the postoperative period. However, if there are many patients with respiratory failure caused by COVID-19 pneumonia in the same region, the resources related to intensive care must be reallocated and there may be situations where surgery is limited to life-threatening emergencies. In the United States, there was a 53% reduction in adult cardiac surgeries nationwide during the early half of 2020 compared with 2019, with a 65% decrease in elective surgical cases and a 40% decrease even in non-elective cases [29]. Our results showed that the number of aortic surgeries was the same as in pre-pandemic years because the urgent intervention was required. A global survey of cardiac surgery centers was conducted among the 61 participating centers of the Randomization of Single vs Multiple Arterial Grafts (ROMA) trial, 60 of which responded: 7 from Asia, 2 from Australia, 31 from Europe, 16 from North America, and 4 from South America. The Survey revealed a greater than 50% reduction in ICU bed availability for cardiac surgery and a median reduction in cardiac surgery case volume of 50% to 75% [30].

The number of CABG procedures decreased significantly in 2020, but this could be due to a decrease in the number of new patients or the possibility that catheter-based treatment was performed instead of surgery. The rate of total mastectomies for breast cancer decreased by only about 6% at the time of the second wave, but there was a 13% reduction in breast-conserving surgery. Possible reasons for this include the avoidance of postoperative radiotherapy during the pandemic, or fewer new patients being referred for surgery due to refrained hospital visits. The number of thyroidectomies also decreased in 2020, especially in prefectures with high infection levels, probably because elective surgeries were reserved for patients with very-low risk differentiated thyroid carcinoma or indeterminate thyroid nodules [31].

Most appendectomies are emergency procedures; hence, the numbers of appendectomies in 2020 and 2019 were similar. The number of appendectomies in children decreased, probably due to triage or selection of conservative treatment. Our speculation is supported by a report from a tertiary hospital in New York State, the epicenter of the pandemic in the U.S., where it expanded inclusion criteria for non-operative management of acute appendicitis to reduce operating room utilization [32]. It is noteworthy that multiple publications have described increased incidences of complicated appendicitis during the outbreak [33, 34]. A recent cross-sectional retrospective study based on the Pediatric Health Information System in the U.S. collected data for all patients diagnosed with appendicitis from 52 children’s hospitals between 2017 and 2020 (n = 19,431). That study concluded that the increased proportion of complicated appendicitis presentations by 4.4% (from 46.5% to 50.9%) during the COVID-19 pandemic was driven by a decrease in uncomplicated appendicitis [35]. Whether the difference in presentation and management of pediatric appendicitis has resulted in inferior clinical outcomes is subject to further investigation. It will be necessary to investigate the number of operations postponed or canceled. It is also an important issue to proceed with a fact-finding survey on how many patients were disadvantaged by delayed surgery or by receiving alternative treatment.

It is known that perioperative infection is highly likely to cause severe disease. An analysis of 1128 patients (94 with preoperative infection) who were confirmed to be positive for novel coronavirus in the perioperative period revealed a very high 30-day postoperative mortality rate of 23.8% (268 patients), with 81.7% of these patients dying of pulmonary complications [36]. Moreover, 15 (44%) of the 34 patients with confirmed infection required ICU management, with a postoperative mortality rate of 20.5% [37]. Osorio J, et al. also reported that COVID-19 positive patients who underwent emergency general and gastrointestinal surgery during the pandemic had more complications and a higher likelihood of failure rescue than COVID-19 negative patients [38].

It should be noted that the rate of asymptomatic patients diagnosed as positive for infection by PCR testing was reported to range from 6.3% to 91.7% [39]; therefore, asymptomatic infected patients cannot be screened by examination alone, which may lead to serious postoperative complications and consequent nosocomial infections. It is necessary to verify whether the status of postoperative complications in surgical patients differs from that in previous years and to identify complications strongly related to COVID-19 infection.

Since May 2020, the cost of preoperative PCR-based screening for infection has been covered by insurance [40] and is expected to contribute to the recovery of surgical volumes. According to a questionnaire survey conducted by the Japan Surgical Society, 41.7% of all facilities performed PCR testing on patients scheduled for operations, and the implementation of this increased from 23.8% in April 2020 to 54.4% in December 2020 [41]. In the future, it will be necessary to flexibly update surgical treatment algorithms in view of the generalization of preoperative PCR testing and the increased vaccination status of the general population.

In conclusion, this real-world data analysis of surgeries based on NCD data could provide an objective picture of the status of surgical treatment under COVID-19 infection. Although a decrease in the numbers of each surgical procedure during the COVID-19 pandemic is evident, more detailed studies are needed to demonstrate the difference in management according to the severity of disease and the condition of the patient. There are multiple causes for the decline in the number of surgeries, including triage, fewer new patients, and postponement of examinations. An evaluation of the impact of these factors should be performed as the next step of the analysis. We hope that the findings of our study will contribute to even better infection control, strengthen the intensive care system, and secure medical resources to enable a sustainable medical supply system in the event of a pandemic.

Supplementary Information

Below is the link to the electronic supplementary material.

595_2021_2406_MOESM1_ESM.pdf (7.1MB, pdf)

Supplementary file1 Weekly volume of 15 procedures according to the three groups (high, medium, low) of regional infection level. Shaded areas show the periods of the first and second pandemic waves (February 26-May 26, and July 1-September 29, respectively) (PDF 7242 KB)

Acknowledgements

We thank Associate Professor Takako Kojima, Department of International Medical Communications, Tokyo Medical University for reviewing and editing the manuscript.

Funding

This work was supported by MHLW Special Research Program Grant Number JPMH20CA2046.

Declarations

Conflict of interest

We have no conflicts of interest to report. Hiroyuki Yamamoto, Urara Isozumi, and Hiroaki Miyata are affiliated with the Department of Healthcare Quality Assessment at the University of Tokyo. The department is a social collaboration department supported by grants from National Clinical Database, Johnson & Johnson K.K., and Nipro Co.

Footnotes

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

595_2021_2406_MOESM1_ESM.pdf (7.1MB, pdf)

Supplementary file1 Weekly volume of 15 procedures according to the three groups (high, medium, low) of regional infection level. Shaded areas show the periods of the first and second pandemic waves (February 26-May 26, and July 1-September 29, respectively) (PDF 7242 KB)


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