1. Caitlyn Grimaldi Premedical Student – College of Charleston
2. Nicholas Grimaldi DO – East Tennessee Spine and Orthopedic Specialists

Abstract

Object 
Observe and assess the effect of intraoperative topical epidural steroids during lumbar discectomies and revision discectomies on postoperative infection rates through a retrospective study design.

Methods
A review of one-hundred lumbar discectomy and/or revision patients under the care of one surgeon from January 2017 to June 2022 was observed and evaluated based on the use of intraoperative topical epidural steroids. Fifty patients received 40 mg of intraoperative epidural steroid triamcinolone before closure while fifty did not receive the steroid. The evidence of infection during the 2–6 week post-operative follow-up in both cases was recorded and compared using a statistical t-test. The age, BMI, and underlying health issues of the patients were also noted and taken into consideration during the review. 

Results
The mean patient age for those who received the steroid during the lumbar discectomy or revision discectomy was 44.2 years old and 48% of patients were male. The mean patient age for those who did not receive the epidural steroid was 46.5 and 42% of patients were male. The mean patient BMI for those who received the steroid was 30.7 and 31.6 for those who did not receive the steroid. Eight percent of patients who received the steroid reported infection while 0% of patients reported infection that did not receive the steroid at any point during their lumbar discectomy. The results were proven to be statistically significant with a p-value of 0.022.

Conclusions
There is good evidence that using topically applied epidural steroids during a lumbar discectomy and revision discectomy increases infection rates among patients. We recommend refraining from the use of intraoperative steroids in lumbar discectomies for all patients in an attempt to avoid infection. This study warrants further evaluation of perioperative epidural steroid use and infection rates.

Keywords: Corticosteroid, infection, lumbar discectomy

Introduction 
A lumbar discectomy is a surgery in which the herniated or degenerated part of the intervertebral disc that is irritating and compressing the spinal nerve is removed from the spinal canal or foramina to relieve radiculitis. Lumbar discectomies are considered a gold standard in spinal surgeries and a safe option for failed conservative treatment in people with symptomatic radiculitis, but it is not without its complications. Lumbar discectomies have an estimated 78-95% success rate at 1-2 years post-surgery(2). However, up to 21% of discectomy patients experience recurrent disc herniation, the most common risk following a discectomy(3). A revision lumbar discectomy may be performed when a previously herniated and surgically repaired disc herniates again. Other potential risks and complications of lumbar discectomies include bleeding, infection, nerve root damage, blood clots, spinal fluid leak, dural tears, and bowel/bladder incontinence. The prevalence of unintended dural tears during lumbar disc surgery is variable, ranging from 1.8 to 17.4%(12). Surgical site infection (SSI) is one of the most serious complications which occur in 0.7 to 12% of lumbar discectomy patients and is most prevalently caused by staphylococcus aureus contamination(13). Common ways SSIs from lumbar discectomies can be treated is through antibiotic therapy or spinal washouts to remove the infected tissue(14). High-risk factors for SSIs include obesity, advanced age, smoking, diabetes, dural tear, and corticosteroid usage(11).

Corticosteroid drugs may be given orally and intravenously for a global effect. They may also be applied locally for a more targeted decrease in inflammation and pain. Intraoperative placement on the nerve root is known to help decrease postoperative pain in lumbar discectomies. Corticosteroids’ mechanism of action is to inhibit mRNA responsible for the interleukin-1 formation and stimulate the production of a glycoprotein called lipocortin that inhibits the activity of phospholipase 2. These actions produce anti-inflammatory, immunosuppressive, and anti-mitogenic effects(1). The immunosuppressive response of cortical steroids has raised concerns about increased risks of postoperative infection and complications. 

Published studies from 2016 have associated intraoperative corticosteroid injections in knee arthroscopies and preoperative steroid injections in total hip arthroplasties with postoperative infections. The studies present statistical significance and suggest delaying the procedure until at least 3 months after corticosteroid injection(4,5). In comparison, applying a topical steroid on the dural tissue during the closing of a lumbar discectomy has been a common approach in surgical practices to decrease postoperative pain(9). Recent studies on this have shown that there could also be complications associated directly with perioperative and intraoperative epidural steroids after lumbar discectomies. In a study published in 2000, it was reported that multiple epidural abscesses and infections were encountered in the steroid group following a discectomy compared to no observed infections in the nonsteroid group(6). Likewise, postoperative effects associated with the use of epidural steroids during lumbar discectomies demonstrated trends in increased infection and complications, but no statistically significant differences between the steroid and control group were justified in 2015 and 2018 published studies(7,10). In addition, it was stated that the administration of the steroid could be concluded to have no significant improvement in postoperative pain(8). These studies were not focused primarily on the prevalence of infection and all studies recommended more specific studies be conducted to validate the significance of complications and infection concerning the intraoperative use of epidural steroids.

After being exposed to these articles in 2020, a surgeon reviewed his record of using intraoperative epidural steroid triamcinolone in lumbar discectomies and the prevalence of postoperative infection. Seeing an increased rate of infection within the previous months that required a spinal washout procedure, he ceased the application of the steroid during lumbar discectomies and revisions thus prompting the undertaking of this study. This study is a review of lumbar discectomy and revision patients under the care of a single surgeon that directly analyzes the relationship between reported postoperative infection and the use of intraoperative topical epidural steroids. Other factors considered during this study included common factors associated with an infection such as body mass index, age, sex, and chronic health conditions like diabetes, heart disease, lung disease, liver disease, and cancer. 

Methods
Using a retrospective study design, one-hundred lumbar discectomy CPT code 63030, and/or revision discectomy CPT code 63042 surgical cases from January 2017 to June 2022 were reviewed and analyzed. Fifty patients that had undergone lumbar discectomy and/or revision surgery consecutively from January 2017 to September 2020 were reviewed for having received 40 mg of intraoperative topical epidural steroid triamcinolone before the closure of the surgery. The length of the procedures did not vary per patient at approximately 30-40 minutes in length utilizing a 2.5 cm incision to allow for a mini-open microdiscectomy using a Taylor retractor for access. Each patient also received Keflex 500 mg, a four days’ supply, postoperatively. The dosage and type of steroid used did not vary throughout the study. 

Fifty additional consecutive patients from November 2020 to June 2022 were reviewed without the use of the intraoperative steroid during the discectomy or revision. The same surgical technique was utilized except for further testing to evaluate preoperative Methicillin-resistant Staphylococcus aureus, the addition of nasal mupirocin (Bactroban) ointment application, and chlorhexidine gluconate (Hibiclens) sponge washes the day of surgery. These were executed in the nonsteroid group to further avoid postoperative infection.

The date of surgery, age, body mass index, and underlying health issues of the one-hundred patients were recorded along with whether or not the triamcinolone steroid was topically applied during the lumbar discectomy. If the body mass index of the patient was less than 18.5 the patient was considered underweight, 18.5 to < 25 fell within the normal range, 25.0 to < 30.0 fell within the overweight range and 30.0 and higher was considered obese. The evidence of infection during the 2–6 week post-operative follow-up in both cases was recorded and then compared using a t-test. A p-value of < 0.05 was considered statistically significant. 

Results 
The demographic and clinical characteristics of the patients involved in this study are summarized in Table 1. Twenty-four out of the fifty patients that received the steroid during their lumbar discectomy surgery in this study were male, twenty-six were female. Twenty-one out of fifty patients that did not receive the steroid were male, twenty-nine were female. The mean age and BMI were similar between the patients with the steroid applied compared to patients that did not receive the topical steroid during the lumbar discectomies. Patients without the steroid had a higher average age of 46.5 by 2.3 years and a higher average BMI of 31.6 by 0.9 (Figure 1). There was no statistical difference between the mean age in these groups (p=0.250), as well as for the patients’ average BMI (p=0.248). Four patients showed infections in their 2–6 week post-operative follow-up appointment from their lumbar discectomy surgery with the application of the topical epidural steroid. These patients required a spinal washout procedure to eliminate the infection within 5 weeks of the identification. None of the infected patients had reported dural tears during their procedure. No patients had infections after surgery without the steroid. No superficial infections were encountered; all infections were considered to be deep. Wound cultures of the infections reported staphylococcus aureus, staphylococcus epidermidis, and klebsiella oxytoca. The t-test to compare the evidence of infection in discectomy cases that had and had not applied the epidural steroid proved to be statistically significant with a p-value of 0.022. 

Out of the one-hundred lumbar discectomies and/or revision discectomies reviewed, twenty patients had underlying health issues that included diabetes and/or medical history of cancer, heart disease, liver disease, and lung disease. As seen in Table 2, half of the patients that were reported to have an infection in the steroid group had diabetes. These same patients were also considered obese with an average BMI of 31.4. 

Discussion
Studies before this have examined and compared the complications and outcomes associated with perioperative and intraoperative use of epidural steroids in surgery but have not been able to establish stable statistical significance. This retrospective study was designed to primarily compare post-operative infection rates in patients undergoing a lumbar discectomy surgery with topical application of epidural steroid performed by a single surgeon. Based on our analysis, the use of topically applied epidural steroids during lumbar discectomies and/or revisions is linked to increased postoperative infection rates (p=0.022). The findings in this study are consistent with the results from the previous studies stated earlier. However, our data was considered more statistically significant. The results of this study offer possible solutions for the prevention of postoperative infections in patients undergoing lumbar discectomies and/or revisions.  

This study has limitations. The sample was relatively small and a larger group would be necessary for further proof of significance. There may be other factors contributing to infection not included in this study. The findings in this study have warranted the further evaluation of preoperative MRSA testing, Bactroban, Hibiclens, epidural injections, and other types of steroid applications.

In conclusion, the results of this study have proven statistical significance that topical application of an epidural steroid is a risk within itself of infection. Because the prevalence of obesity was the same in both experimental groups, it was decided not to be the factor contributing to infection. We recommend refraining from the use of intraoperative steroids in lumbar discectomies for all patients in an attempt to avoid infection as well as allowing for nasal mupirocin and Hibiclens sponge washes before surgery to further prevent infection. This study warrants further evaluation of perioperative epidural steroid use and infection rates.

References

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