The global COVID-19 pandemic has significantly impacted health care worldwide. Especially surgical care was drastically reformed during different phases of the pandemic, to spare clinical capacities and diminish disease transmissibility. The influence of COVID on surgical outcomes, especially related to postoperative complications in plastic surgery, are until now not entirely known. Therefore, this present study aimed to fill this knowledge gap.
This study focussed on patients undergoing any type of reconstructive breast surgery. It must be noted that our IBR group was notably smaller than our ABR and PBR groups. This is due to the fact that the primary inclusion center of this study, Maastricht University Medical Center, is a renowned tertiary referral hospital for autologous breast reconstruction in the Netherlands.
The incidence of COVID-19 in the IBR group was remarkably low. Operative time, hospitalization and time to full recovery are markedly shorter in IBR patients compared to ABR. This possibly makes IBR patients less prone to attract COVID-19. While the same applies to PBR patients, this population is generally older and has more comorbidities; both increasing the vulnerability to a COVID-19 infection. Nevertheless, it is also well possible that the relatively low incidence of COVID-19 in IBR patients was due to the limited sample size.
The primary outcome of this study was the postoperative complication rate. In the ABR and PBR group, COVID-positive patients had a higher incidence of postoperative complications. Although our findings are statistically significant, it must be noted the 95% confidence intervals are wide. Therefore, the true effect size may vary. Most complications were classified as minor, and did not require surgical intervention. A specifically notable finding was the significantly impaired wound healing at all surgical sites in COVID-positive compared to COVID-negative patients. Fat necrosis and surgical site infection occurred more often in COVID-positive patients as well. Complication rates in the IBR group could not be statistically tested, therefore no conclusions can be drawn for this specific population. However, the results of the ABR and PBR group are strikingly similar and indicate increased susceptibility to develop postoperative complications in COVID-positive patients.
The clinical need for better understanding of COVID-19 and its implications on surgical care has led to an exponentially increasing scientific interest. Abundant evidence shows that perioperative COVID-infection elevates risks of cardiopulmonary, renal, septic and thromboembolic complications, as well as postoperative mortality across a wide range of surgical disciplines [12–18]. Therefore, anaesthetic and surgical associations recommend postponing elective surgical procedures after COVID-infection [19–21].
The pandemic evolved over time: different virus variants became endemic, and vaccinations became available. At this moment there is no evidence suggesting differences in surgical outcomes depending on the virus variant or pandemic phase [21, 22]. Contrarily, vaccination does contribute positively. This is partly due to a diminished disease risk, but secondly due to mitigation of the severity of the COVID-19 symptoms. Vaccinated COVID-positive patients have favourable surgical outcomes and lower complication rates compared to unvaccinated COVID-positive patients [23].
Although a vast amount of knowledge is available regarding surgical outcomes, preferable timing, and factors that affect postoperative recovery in COVID-positive patients; there is relatively little mention of surgical site complications. Nevertheless, a few studies and case series have shed light on this subject.
In cardiothoracic surgery several case series and a case-control study highlighted clinical cases of COVID-positive patients with anastomotic complications, wound disturbances and sternal dehiscence in patients after open cardiac surgery [24–26]. The described cases share all a component of unusualness: the complications developed sudden and without any accompanying signs, were more severe than usual, and often followed an uncommon course in time. The Cardiothoracic Interdisciplinary Research Network and COVIDSurg jointly confirmed that wound and sternal dehiscence occurs more often in patients with (especially postoperative) COVID-infection [27].
For oncological surgery a few case series described heightened risks for postoperative complications including impaired wound and anastomotic healing in COVID-positive patients as well [28, 29]. Similarly, unusual cases of wound dehiscence have been described in pressure ulcer surgery with local reconstruction.
Additionally, several reports of comparable complications have been published regarding flap reconstructions. Inouye et al. described two cases of free flap head and neck reconstruction, where both patients contracted COVID-19 postoperatively and presented with severe flap dehiscence and donor site skin graft failure [30]. In these cases, the unusual time span is again striking. The complications manifested at 16 and 20 days postoperatively, whereas in earlier stages the wound healing was unremarkable. Secondly, Chen et al. described a case of partial anterolateral thigh flap failure six weeks after surgery in a patient with active COVID-infection [31]. Furthermore, Talmor et al. published a case of complete necrosis of a pedicled nasoseptal flap for closure of a skull base defect four weeks postoperatively with concurrent COVID-19 infection, while the flap was still viable at endoscopic inspection two weeks postoperatively [32]. Finally, Benmoussa et al. described a case centered around a chimeric double skin paddle free fibula flap and a thoracodorsal artery perforator flap used for an intraoral defect, which both became necrotic synchronous with a COVID-19 infection one week postoperatively [33].
The findings of this present study in conjunction with the previously described literature suggests that patients with COVID-infection have an increased susceptibility to develop surgical site complications. They seem especially prone to impaired wound healing. This may be a result of inflammation and thrombosis in the surrounding microvasculature.
It is commonly acknowledged that COVID-19 affects microvasculature and causes aberrancies in haemostasis. A key role is reserved for angiotensin II (Ang II). Angiotensin converting enzyme 2 (ACE 2) is the functional receptor of the COVID-19 virus. ACE 2 is expressed strongly on endothelial cells, thereby providing an entry point for invasion by the virus. Binding to the ACE 2 receptor elicits Ang II production. Circulating levels of Ang II elevate as a result. Besides its vasoconstrictive properties, Ang II is also a pro-inflammatory mediator. It increases production of several other cytokines including antifibrinolytic mediators. This promotes (micro)vascular fibrin deposition and reduces demolition of thrombi [34–36].
Besides Ang II, also platelets presumably play a role in the disruption of haemostasis induced by COVID-19.[37] In COVID patients elevated levels of circulating platelets are observed; likely because the SARS-CoV-2 Spike protein directly stimulates platelets [38]. As platelets are an important element in primary haemostasis, this contributes further to a COVID-virus induced hypercoagulable state.
As wound healing and free flap survival rely heavily on adequate revascularization, they are dependent on surrounding microvasculature. It is therefore well imaginable that these coagulatory and inflammatory changes directly related to the COVID-19 virus have potential to negatively influence surgical site outcomes.
This study is the first to shed light on postoperative outcomes and complications associated with COVID-19 after reconstructive breast surgery. Unfortunately, the IBR group was relatively small and had a lower incidence of COVID than the ABR and PBR groups. Therefore, no statistical testing could be conducted which limits our results of this group. Future research with larger sample sizes would be valuable to assess whether our findings in ABR and PBR patients can be extrapolated to IBR patients as well. A larger sample size would also provide additional power to confirm our results. Another arguable limitation is that we did not take into account vaccination status in this study. Although vaccinations protect against perioperative mortality and morbidity, it remains unknown whether this also accounts for surgical site complications. Additional research into the hypothesized underlying pathophysiological mechanisms is also recommended to better understand how COVID affects postoperative recovery and develop risk-reducing strategies.