Vaping and Orthopedic Surgery: Perioperative Management

Introduction

ECs are battery-operated devices that heat a metal coil to vaporize e-liquid without tobacco or combustion.¹ The act of inhaling the resulting aerosol is commonly referred to as “vaping”.¹ While combustible smoking rates have declined, e-cigarettes have risen due to their perceived safety.¹ In 2020, 68 million people vaped globally,² with 3.7% of U.S. adults using ECs.³ By 2022, 3.3% of middle schoolers and 14.1% of high schoolers had used ECs in the past 30 days.³ ECs have evolved into over 200 brands, generating a $1.7 billion industry projected to reach $10 billion in the next decade.⁴ While EC use is growing, its long-term consequences and perioperative risks remain poorly documented. Orthopedic surgeons must gain a comprehensive understanding of ECs to make surgical decisions, effectively communicate risks, and improve clinical outcomes.⁴ By addressing these challenges, surgeons contribute to the optimal care of their patients.

Relevance to Orthopedic Surgery

Optimizing patient outcomes in orthopedic surgery require surgeons to address both traditional tobacco and e-cigarette usage prior to the procedure.⁵ However, despite being aware of the importance of nicotine cessation, surgical practices often remain unchanged. Lilley et al., revealed that 41% of orthopedic surgeons never delayed surgery due to nicotine use, while 39% delayed surgery less than three months.⁶ Surprisingly, urine tests for nicotine cessation were rarely used, with 79% of respondents almost never administering them to elective surgery patients. Due to cost consideration, Ellis et al. suggested that serum cotinine testing should only be used for high-risk patients with elevated urine cotinine levels.⁷ Further, more than half (53%) spent less than five minutes on preoperative counseling about the increased risk nicotine poses on postoperative outcomes.⁶ Only a mere 20% of responding physicians frequently or almost always used cessation programs during the perioperative period.^6,7

Nicotine cessation is challenging, and although an estimated 40% of patients attempt to quit yearly, less than 5% are successful.⁸ A surgical encounter is a “teachable moment” that may provide extra motivation for patients to permanently cease use.^8,9 Evidence supports the effectiveness of preoperative smoking cessation interventions, with a rate ratio for quitting of 2.02 in patients undergoing major surgery, and patients who received such interventions being 2.7 times more likely to achieve long-term cessation.⁸ Even without intervention, cessation rates range from 47 to 462 per 1000.⁸ However, most orthopedic surgeons do not delay surgery due to nicotine consumption despite patient’s desire to stop smoking before surgery.

Surgery offers a unique opportunity to help patients stop consuming nicotine permanently. Various techniques, including nicotine replacement therapies, medication, and behavioral interventions, may be employed to facilitate cessation.⁸ Interestingly, several studies reported the accuracy of self-reported non-smoking status on intake forms may underestimate true smoking incidence by up to 45%, despite a 97.6% accuracy rate reported by Ellis et al.⁷ The optimal timing of nicotine cessation is crucial for the orthopedic surgeon, with a longer period of abstinence associated with fewer postoperative complications.¹⁰ Research suggest that at least 4 weeks of smoking abstinence before surgery reduce complications, and the preoperative period can serve as an opportunity to improve long-term cessation rates.¹¹ However, despite patient education on the dangers of nicotine use, a significant number of patients reported increased vaping on the day of surgery compared to smoking.¹²

Cytotoxicity

Despite the perception that EC aerosol is safe, it contains harmful chemicals including carcinogens, heavy metals, and flavoring agents. With over 8,000 different flavors on the market, the health effects of flavoring agents remain mostly unknown. Cinnamon-flavored e-liquids exhibit high cytotoxicity, an increased inflammatory response, and impaired neutrophil phagocytotic function.¹³ Cinnamaldehyde, has gained special attention, since being identified as the most potent chemical in e-liquid.¹³

E-liquids and aerosols may induce cytotoxicity through oxidative stress, resulting from an imbalance between cell antioxidant defenses and reactive oxygen species (ROS).¹³ Shaito et al., reported high ROS production and inhibition of osteogenic differentiation in response to e-cigarette extract exposure.¹⁴ Furthermore, e-cigarette aerosol extract exposure has been found to impair both proliferation and osteoblastic differentiation of bone marrow-derived mesenchymal stem cells (MSCs).¹⁴ These detrimental effects on cellular function and bone repair have significant implications, particularly for individuals with skeletal system disorders such as osteoarthritis, osteoporosis, and scoliosis.^14,15

Surgical Site Infection and Wound Healing

Smoking’s impact on wound-healing and surgical site infection (SSI) has been well- documented. Sørensen found that smokers were four times more likely to experience necrosis than nonsmokers, while surgical site infection, dehiscence, and healing delay were twice as common in smokers.¹⁶ The acute vasoactive effect can lead to the development of postoperative necrosis in tissues with fragile blood supply, such as reconstructive tissue flaps. Furthermore, smoking has been shown to reduce the inflammatory healing response, impair oxidative bacterial killing mechanisms, delay the proliferative healing response, and alter collagen metabolism, which can result in complications like dehiscence, incisional hernia, and lack of fistula or bone healing.¹⁶ Moller et al., found that four weeks of smoking abstinence significantly reduced the incidence of incisional wound infection, although its impact on SSI varied among patients. Therefore, the required abstinence time prior to surgery may fluctuate per patient and necessitates individualized considerations.¹⁷

Carbon monoxide, a component unique to traditional combustible cigarettes, was identified as a potential mechanism that not only binds to hemoglobin but also shifts the oxyhemoglobin dissociation curve left, leading to decreased oxygen supply and potentially contributing to SSI.¹⁸ Troiano et al., studied wound healing in rats exposed to EC vapor or cigarette smoke and found substantially higher rates of flap necrosis in both groups compared to unexposed rats, even at similar nicotine levels, indicating that EC vaping is not safer than cigarette smoking for surgical wound healing.¹⁹

Circulation

Daftari et al., conducted a study in which autologous cancellous bone was transplanted to the eyes of 24 rabbits, half of which received nicotine and the other half received a placebo. The results indicated that nicotine is associated with delayed revascularization and a smaller percent area of revascularization, with a larger number of grafts showing necrosis.²⁰ Inhaling nicotine leads to increased circulating catecholamines, which can impair microcirculation in areas such as the hand.²¹ Pywell et al., discovered that smokers experience increased superficial microcirculation after using 0 mg ECs, attributed to components like glycerol present in e-liquids. However, a 24-mg nicotine EC significantly reduced hand microcirculation during and up to 20 minutes after inhalation. Interestingly, it was found that nicotine inhalation, rather than smoking, reduced blood flow in the hand, as demonstrated by inhaling on a 0-mg nicotine EC.²¹ Thus, ECs have been shown to reduce cutaneous blood flow in peripheral circulation in humans, so orthopedic surgeons should be aware of the circulation reductions in patients using ECs.²²

Bone Health

Smoking increases the risk of bone fracture, slows healing, and nonunion.²³ While genetics explain 60-80% of bone mineral density (BMD), modifiable factors such as smoking play a significant role in the remaining percentage.²³ Smoking harms BMD by decreasing calcium absorption, vitamin D levels, body mass, and altering hormone levels. The harmful components of combustibles, such as nicotine and cadmium damage bone cells.²³

Nicholson et al. investigated the effect of EC vapor on bone in vivo, exposing mice to aerosols for up to 6 months. While no significant effect on cortical bone strength, stiffness, or hydroxyapatite content was reported, microfractures were evident in the femur of mice. Moreover, microfractures occurred with aerosols containing only propylene glycol and vegetable glycerol, suggesting an effect not entirely mediated by nicotine or flavoring chemicals.²⁴

Recent studies suggest that e-liquid ingredients may harm the body’s ability to produce healthy bone structures, increasing the risk of osteoporosis, and potentially promoting other musculoskeletal diseases like rheumatoid arthritis and osteoarthritis.²⁵ This highlights the importance of considering the impact of ECs on adolescents and young adults, who make a significant portion of EC users. Prolonged use of ECs may lead to reduced bone mineral density into adulthood.¹⁵ It was found that nicotine-rich EC vapor reduced the mineralization and alkaline phosphatase activity of Saos-2 osteoblasts, while inducing apoptosis.²⁴ Additionally, nicotine-rich EC vapor had more pronounced negative effects on osteoblast function than nicotine-free EC vapor, suggesting that nicotine plays a significant role in the impact of EC vapor on new bone synthesis.²⁴

E-liquids have been shown to harm osteoblasts. Some e-liquids were applied to human Saos-2 and MG- 63 cells, causing reduced cellular viability, even when nicotine-free. Besides, formaldehyde and acetaldehyde decreased proliferation and increased cell death in U2Os. In addition, both acetaldehyde and acrolein also inhibited osteoblast alkaline phosphatase activity and mineralization.²⁴ Carbonyl compounds following EC use can adversely affect osteoblast function. Prolonged exposure to cadmium from ECs may also be harmful to bone health, similar to smoking. A Swedish study found that even low levels of cadmium exposure had a negative effect on bone health.²⁵

Fractures and Healing

Studies have shed light on the impact of smoking on orthopedic outcomes. For instance, Kanis et al. conducted a study involving 60,000 smokers, and identified a 25% increased risk for fractures among this population.²⁶ Tucker et al., observed no significant difference in a rat femur fracture model between smoking and vaporized nicotine, but trends indicated concerns regarding the impact of vaporized nicotine on bone formation. The vaporized nicotine groups, exhibited lower levels of total mineralized and immature bone volume, indicating potential adverse effets.²⁷ Donigan et al., showed that transdermal nicotine decreased the mechanical strength of healing fractures and resulted in an increased rate of nonunion compared to controls in a rabbit model.²⁸ Furthermore, Agoons et al., found a 46% higher prevalence of fractures in EC users compared to non-users, with a graded increase in prevalence for traditional cigarette smokers and dual users of traditional and e-cigarettes, indicating that e-cigarette use may harm bone health.²⁹

Although the mechanisms by which e-cigarettes affect bone health are unclear, several factors have been identified. EC aerosols have been linked to the suppression of cellular antioxidant activity, oxidative stress, and DNA damage.²⁹ Moreover, nicotine is present in both traditional cigarettes and ECs and may have direct cytotoxic effects on the activity of bone-forming osteoblast. Cigarette smoking has been shown to dysregulate hormones, resulting in reduced BMD and increased the risk of fractures.²⁹

Conclusion

Orthopedic surgeons must recognize that vaping is not a healthier alternative to smoking when it comes to infection, circulation, and bone health/healing. E-liquid, used in vaping devices, has its own negative consequences, and efficiently delivers nicotine to consumers. Although vaping avoids the known harm caused by combustible cigarette smoke, it has its own impact on orthopedic patients. Surgeons must approach vaping in the same way as they have treated smoking. There is a biological basis for surgeons to increase their awareness of its effects of vaping, while advocating for nicotine cessation for their surgical patients.

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The authors do NOT have any potential conflicts of interest for this manuscript.

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