Clean or Dirty? A Systematic Review of Splash Basin Use and Its Infectious Potential in Orthopaedic Surgery

Abstract

Background

Splash basins are used in orthopaedic surgery cases to wash and hold instruments

intraoperatively. This systematic review aims to summarize information on contamination of splash basins intraoperatively.

Methods

A systematic review was conducted using the following search terms: “splash basin” or “splash bucket.” Two authors independently reviewed the literature. Studies were included if they reported on intraoperative splash basin contamination rates. Studies were excluded if they were not relevant to orthopaedic surgery, non-English articles, or repeat studies yielded by different online databases.

Results

There were seven studies included in this review. The median contamination rate of sterile water or physiologic saline splash basins was 23.9% [range: 2%-74%]. The addition of surgical antiseptics to sterile water splash basins was associated with 0% contamination rates in two studies. The most frequent splash basin contaminants identified in bacterial culture were coagulase negative staphylococcus (50%) and staphylococcus aureus (10%).

Conclusion

The splash basin appears to be a frequent source of contamination in the operating room. Many studies suggest abandoning splash basin use altogether, although the efficacy of alternative methods such as cleaning instruments with lap pads in avoiding contamination of the sterile field has not been studied. Further investigation into surgical teams’ use of the splash basin and the contents of the splash basin as they relate to contamination rates may help advance our understanding of optimal use of this surgical tool. Shorter case durations and dilute surgical antiseptics in splash basins appear associated with lower splash basin contamination risk.

Level of Evidence: V

Introduction

Splash basins are used in orthopaedic surgery to clean and hold instruments intraoperatively.^1-7 Splash basin use is still encouraged by nursing and surgical technologist associations to maintain sterility.^8,9 These splash basins are recommended to be filled with sterile water given the potential for instrument corrosion with normal saline.¹⁰

In 2013, an international committee of orthopaedic surgeons recommended against splash basin utilization because of unacceptably high contamination risk.¹¹ More recently, two study groups added dilute surgical antiseptics to splash basins, and subsequently found a significant decrease in basin fluid contamination rates.^6,7 Despite these developments, the overall use of splash basin use remains largely unchanged over the years.¹⁰ Although they reside on the sterile field, splash basins have large surface areas that could allow for airborne microbes to settle and house many instruments soiled with bioburden. Anto et al. reported that on average, 46 instruments were placed in the splash basin during orthopaedic surgery cases.³ The potential for splash basin contamination is particularly worrisome given instruments are taken from it and reintroduced into the operative site.

Prevention of intraoperative contamination is important given the persistent one to two percent periprosthetic joint infection (PJI) rate in joint arthroplasty cases.¹² PJI requires long courses of antibiotics and subsequent operative interventions to definitively treat.¹³ There have been important strides made in reducing PJI rates such as the use of prophylactic antibiotics.¹⁴ However, efforts targeted towards reducing contaminants in the operating room and reservoirs for their introduction into the surgical wound are important in continuing to improve infectious outcomes after orthopaedic surgery.

The maintenance of splash basin sterility appears vital in mitigating infection risk. An overview of splash basin contamination rates and common microorganisms has not been well-described. In this systematic review, we explore the notion that perhaps splash basins are not as sterile as previously thought and give recommendations for best practices with this surgical tool.

Methods

Review methodology

A systematic review was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines of publications from 1970 to 2021. Pubmed and Ovid databases were searched using the following search terms: “splash basin” or “splash bucket.” Two authors independently reviewed the literature. Studies were included if they reported on intraoperative splash basin contamination rates. Studies were excluded if they were not relevant to orthopaedic surgery, non-English articles, or repeat studies yielded by different online databases. Citations of relevant studies were also reviewed. Our PRISMA methodology is summarized in Figure 1. An example of a splash basin after a routine clean primary elective hip arthroplasty at our institution can be found in Figure 2.

Figure 1.

Displays a summary of our systematic review methodology.

Figure 2.

A used splash basin after a primary total hip arthroplasty.

Data Aggregation and Reporting

Each study’s first author, journal published, year published, country of investigation, study design, and number of cases was collected. Patient and operation information reported by studies including patient age and sex, operations completed, case type (clean, contamination/dirty), urgency (elective vs. emergent/urgent) were also included. Perioperative statistics including operative time, use of prophylactic antibiotics, and operating room airflow (laminar airflow, rate of air exchange) were noted. Culturing technique, contamination rates, and bacterial species yielded from culture were listed. Clinical outcomes relevant to infection and follow-up times were also recorded when available.

Additional Analysis

The rate of bacterial species contaminating the splash basin was calculated by dividing the number of reported cases for a given bacterial species or group in all studies by the total number of organisms reported.

Results

Systematic Review Synthesis

There were 39 studies yielded from our initial search. After title and abstract review, there were 9 duplicates removed and 19 studies that did not report on splash basin contamination rates. The following reasons were used to exclude studies after manuscript review: non-English article (n=1), review paper (n=2), and no splash basin contamination rate reported (n=1). There were 7 studies included in our study after exclusion.^1-7 Relevant information about study design and publication can be found in table 1.

Case Selection

Five of seven studies cultured joint arthroplasty cases,^3-7 four of which were specified as being elective.^3-6 Of the remaining two, one investigated splash basin samples of hand, joint, and trauma orthopaedic cases, including open injuries.¹ The other cultured splash basins from elective orthopaedic cases.²

Splash Basin Fluid

There were six studies that used sterile water in splash basins (range 2%-74%)^1,3-7 and one by Anderson et al. that used physiologic saline (62%).² Two studies used surgical antiseptics diluted in sterile water. There were 53 splash basins with 0.05% chlorhexidine solution cultured in the Lindgren study⁶ and 52 splash basins with 0.02% povidone-iodine in the Nazal study.⁷

Contamination Rates and Culturing Technique

The median contamination rate of sterile water or physiologic saline splash basins was 23.9% [range: 2%74%]. In the 1980s, the first two studies on splash basin contamination reported the highest rates of contamination found in this review. Baird et al. found a 74% contamination rate in randomly selected clean or contaminated orthopaedic cases, while Andersson et al. found a 61.9% contamination rate in consecutive elective orthopaedic cases. Both studies did not limit their patient population to arthroplasty patients,^1-2 did not utilize laminar airflow, and poured splash basin fluid through a grid membrane for culture. Anto et al. found a 23.8% contamination rate in 21 splash basins used in primary elective total joint arthroplasties, in operating rooms with laminar airflow, and used the grid membrane culturing technique.³ The study with the lowest contamination rate (2.2%) by Glait et al. was completed in randomly selected elective joint arthroplasty cases, in operating rooms with laminar airflow, and used a culture swab technique along the bottom of the splash basins.⁴ Although it was published in 2014 with 20-year follow-up, the Jonsson et al. study was completed from 1991 to 1992, found a 24.1% contamination rate in 92 consecutive primary total joint arthroplasties, in operating rooms without laminar airflow, and used a culture swab technique to yield organisms for culture.⁵

Table 1.

Study Designs of Included Splash Basin Contamination Studies

#	Author	Year	Location	Cases	Design	Inclusion	Exclusion
1	Baird	1984	USA	78	CS	Randomly selected orthopaedic cases
2	Andersson	1984	Sweden	21	CS	Consecutive, elective orthopaedic procedures, longer than 1 hour
3	Anto	2006	Ireland	21	CS	All patients undergoing primary THA or TKA
4	Glait	2011	USA	46	CS	Randomly selected clean primary joint arthroplasty cases	Positive culture on preop control swab
5	Jonsson	2014*	Iceland	90	CS	92 consecutive primary total hip and knee replacements for osteoarthritis
6	Lindgren	2018	USA	100**	RCT	Primary TKA/THA cases	Revision hx of PJI, CHG allergy, declined participation, basin discarded, poor sterile technique in collecting sample, excess coagulation incorrect randomization, splash basin unused
7	Nazal	2020	USA	100***	RCT	Age >=18, undergoing total joint arthroplasty	Revision, hx of PJI, shellfish allergy, splash basin unused

*Study occurred from 1991-1992, published in 2014 with 20 year follow-up.

**Sterile water group (n=47), chlorhexidine group (n=53)

***Sterile water group (n=48), chlorhexidine group (n=52)

Index: #= number. Pub Year= year of publication. USA= United States of America. CS= Case series. RCT= Randomized Controlled Trial.

Prior to 2018, every study utilized sterile water other than Andersson et al. They used physiologic saline in their retrospective case series. Two studies, published in 2018⁶ and 20207, were both randomized controlled trials, with sterile water control groups and dilute surgical antiseptic experimental groups. Lindgren et al. found an 8.5% contamination rate and Nazal et al. found a 47.9% contamination rate in sterile water splash basins of primary elective total joint arthroplasties using grid membrane culturing techniques. Splash basins with surgical antiseptic diluted in sterile water had no contamination detected after grid membrane culture.^6,7 Contamination rates by study can be found in Figure 3.

Figure 3.

Demonstrates splash basin contamination rates reported in literature. All studies used sterile water or physiologic saline unless otherwise specified (sterile water [SW], chlorhexidine gluconate [CHG], povidone-iodine [PI]).

Microbial Culture Findings

There was a total of 203 contaminants identified amongst all studies. Amongst them, the most frequent bacterial species found in culture were coagulase negative Staphylococci including Staphylococcus epidermidis (49.8%), Staphylococcus aureus (9.9%), unspecified gram-negative rods (7.9%), Diptheroids (7.4%), Bacillus species (3.9%), Pseudomonas species (3.4%), other gram-positive cocci (3.4%), Corynebacterium species (3.0%). Other organisms (12%) were as follows: unspecified other (2.5%), Micrococcus species (2.5%), Lactobacillus species (1.0%), actinobacter (0.5%), Streptococcus viridans (0.5%), Cupriavidus paucaulus (0.5%), Moraxella (0.5%), Kocuria species (0.5%), Clavicbacter michiganensis (0.5%), and Sphingobacterium multivorum (0.5%) [Figure 4].

Figure 4.

Shows the frequency of organisms contaminating splash basins.

Only one study commented on non-microbial contents of the splash basin. Lindgren et al. found soft tissue or fat, which they referred to as debris, in 54% of fluid samples.

Surgical Staff

The number of surgical staff in the operating averaged 7 in one study [range: 4-10]², and 9 in two other studies (SD: 1.8 people³; 95% CI: 8-96). The number of gowned personnel was specified only by one study, which found an average of 3 scrubbed in people per surgery.³ There was no association found in the only study that analyzed a relationship between number of OR personnel and splash basin contamination.²

Splash Basin Location

Andersson et al. studied splash basin contamination as it relates to placement in the operative field.² They found the following contamination rates based on splash basin placement: on the assisting table (8/12 samples), under the assisting table (2/3 samples), or on a table two to three meters from the assisting table (3/6 samples); the authors determined there was no significant difference between splash basin contamination based on placement in the OR. Another study specified splash basin placement on the back table but did not attempt to study the association between splash basin location and contamination rates.⁶

Splash Basin Handling/Operative Time

Andersson et al. limited splash basin samples to cases that lasted at least one hour² but did not report any analysis between splash basin contamination and operative time. No other studies excluded splash basins from cases with relatively short operative times.

All but two studies referred to splash basin opening time and incision time interchangeably. Lindgren et al. found an average time from splash basin procurement to fluid sample collection of approximately 90 minutes, which they acknowledge was less than other studies.⁶ There was no time from splash basin opening to incision reported, or analysis on the association of operative time and contamination in their study.

Glait et al. determined an average of 75 minutes (SD: 30 minutes) between splash basin opening and initial incision.⁴ The only case of contamination was recorded in the study was from a unicompartmental knee arthroplasty case with a time from basin opening to wound closure of 240 minutes, relative to the mean of 180 minutes (SD: 45 minutes) in uncontaminated cases.

This trend between longer operative times and greater risk of contamination was shared by other studies included in this review. One found that 35% of splash basin samples collected from cases lasting 130 minutes or longer were contaminated relative to 13% of samples collected before that timepoint.⁵ Nazal et al. also found that mean operative time was significantly higher in cases with contaminated splash basins (70 minutes [SD: 33 minutes]) relative to negative samples (59 minutes [SD: 16 minutes]).⁷

Laminar Airflow

Laminar airflow was used by two studies,^3,4 not used by two studies,^2,5 and not reported on by the remaining three.^1,6,7 Amongst studies using laminar airflow, there were 300 air changes a minute and contamination rates of 23.8%³ and 2.2%.⁴ Studies not using laminar airflow reported 12 and 17 air changes a minute, and contamination rates of 61.9% and 24.1%, respectively.^5,2

Postoperative Infection

Postoperative infection rates ranged from 0-2.4% in studies.^1,3,5 There was no association between splash basin contamination and infection.⁶ One study found a 2.4% infection rate (1/41 cases) in contaminated splash basins relative to 2.0% infection rate in uncontaminated controls (1/49 cases), with no significant difference between groups.³

Discussion

Splash basin contamination appears to be a significant problem in orthopaedic surgery. A wide range of contamination rates is reported in the literature likely due to differences in culturing techniques, case selection, and operating room sterility practices between study groups.^15-21 This variability does not discount the splash basin as a potential source of infection, particularly in longer orthopaedic cases.

The most frequent contaminants, coagulase negative Staphylococci and Staphylococcus aureus, are also the most frequent causes of periprosthetic joint infection in total joint arthroplasty cases.¹² Many contaminants appear to be human skin flora.²² These bacteria also may be more likely to come from the operating room environment than the patient’s own skin or surgical wound.²³ They are most likely spread to the splash basin in a similar way they are spread to the operative site, through direct contact with the surgical team’s gloves or instruments.^24,25

The use of surgical antiseptics appears highly effective in reducing the frequency of splash basin contamination, perhaps because of their efficacy against staphylococci species.²⁶ With no contamination being found in splash basins using surgical antiseptics (0.05% CHG solution,⁶ 0.02% PI solution),⁷ and no reported side effects or significant additional costs amongst studies using them,²⁷ this intervention deserve further investigation for incorporation into clinical practice.

There are no studies directly comparing contamination rates between different surgical antiseptic solutions or differing concentrations of antiseptic. More study on protocols for patients with known allergies to surgical antiseptics or changes in wear properties of instruments after the addition of surgical antiseptics is also needed.^28,29

Knobben et al. described the potential for intraoperative sterilization using chlorhexidine gluconate, comparing colony forming units after inoculation of gloves with Staphylococcus species.²⁴ They showed that immersion in 0.04% CHG solution reduced colony forming units on contaminated gloves, while at concentrations of CHG higher than 0.4%, there were no bacteria found. The potential for dilute surgical antiseptics to offer continuous intraoperative sterilization of surgical instruments or surgical teams’ gloves may be a promising additional use of the splash basin in the future.

Although not well-studied in relation to splash basin contamination, both operative time and operating room traffic are known risk factors for increasing the likelihood of operating room contamination.^17,19,21 One study identified a direct relationship between time exposed to the OR environment and open tray contamination, even in a closed operating room environment with no traffic.³⁰ There is also a two-fold increase in airborne contamination reported while patients are prepped for surgery;³¹ the forty-minute delay reported by Glait et al. between splash basin opening and incision appears to place splash basins at an avoidably high risk of contamination.⁴ Additionally, staff leaving or entering the OR can change local air flow and expose the sterile field to contaminants.¹⁹

The splash basin should be opened as close to the time of first use as possible. Another logical best practice may be opening a new splash basin or replacing the basin fluid after given time periods have passed in cases, as is recommended for sterile gloves.³² Threshold splash basin dimensions, levels of fluid debris (fat, blood), and operative times that significantly increase the risk of contamination are unknown. Limiting operating room traffic and placing splash basins in areas where passersby are unlikely to be in proximity also appears prudent in avoiding splash basin contamination.

Another factor that may influence the settling of microbes in the splash basin is airflow within the room. Ventilation systems may have been a sources of less typical splash basin contaminants in this systematic review that do not colonize human skin such as Kocuria species or Sphingobacterium multivorum.^33,34 Laminar airflow, as opposed to conventional turbulent ventilation, is meant to sweep airborne particles away from the operative wound.³⁵ Early results in lowering surgical site infection rates were promising but failed to control for confounders like antibiotic use.³⁶ A recent systematic review and meta-analysis drew into question the efficacy and cost-effectiveness of laminar airflow in preventing surgical site infections.³⁷ Importantly, big data analysis may fail to consider operation dependent factors such as correct set up of laminar airflow systems and modified operating room practices to maximize its efficacy.³⁸ Operating rooms should be oriented to reduce particulate matter settling on the sterile field regardless of laminar or turbulent airflow systems being used.

There are limitations of this systematic review. With widespread reports of splash basin contamination, there is also the possibility of abandoning the splash basin in favor of wiping instruments with a lap pad. However, there have been no studies comparing intraoperative rates of contamination with and without splash basin use. Also, some of our recommendations are rooted in studies that refer to operating room sterility rather than splash basin sterility. Until splash basin specific studies are conducted, these more general studies on operating room contamination seem logical to guide best practices.

In an era where postoperative complications can increase healthcare cost burden and negatively impact patient care, it is important to take all steps possible to ensure sterility during all surgical cases. Existing studies demonstrate that these basins can be a frequent source of contamination. However, there are many factors that can decrease the risk of contamination in these basins, namely shortened duration of use and incorporation of dilute surgical antiseptics. Surgeons and surgical staff should remain cognizant of these factors and adjust practices accordingly to decrease the risk of splash basin contamination.