Harboring Contaminants in Repeatedly Reprocessed Pedicle Screws

A prospective study to identify preoperative serum parameters for spinal implant infection detected by sonication fluid culture

PURPOSE

Low-virulent microorganisms identified on pedicle screws by sonication fluid culture (SFC) are an important cause of implant loosening. While sonication of explanted material improves the detection rate, the risk of contamination exists and no standardized diagnostic criteria for chronic low-grade spinal implant-related infection (CLGSII) are stablished. Besides, the role of serum C-reactive protein (CRP) and procalcitonin (PCT) in CLGSII has not been adequately investigated.

METHODS

Blood samples were collected prior to implant removal. To increase sensitivity, the explanted screws were sonicated and processed separately. Patients exhibiting at least one positive SFC were classified in the infection group (loose criteria). To increase specificity, the strict criteria only considered multiple positive SFC (≥ 3 implants and/or ≥ 50% of explanted devices) as meaningful for CLGSII. Factors which might promote implant infection were also recorded.

RESULTS

Thirty-six patients and 200 screws were included. Among them, 18 (50%) patients had any positive SFCs (loose criteria), whereas 11 (31%) patients fulfilled the strict criteria for CLGSII. Higher serum protein level was the most accurate marker for the preoperative detection of CLGSSI, exhibiting an area under the curve of 0.702 (loose criteria) and 0.819 (strict criteria) for the diagnosis of CLGSII. CRP only exhibited a modest accuracy, whereas PCT was not a reliable biomarker. Patient history (spinal trauma, ICU hospitalization and/or previous wound-related complications) increased the likelihood of CLGSII.

CONCLUSION

Markers of systemic inflammation (serum protein level) and patient history should be employed to stratify preoperative risk of CLGSII and decide the best treatment strategy.

The Environmental Impact of Spine Surgery and the Path to Sustainability

STUDY DESIGN

Narrative literature review.

OBJECTIVE

The aim of this study was to review published literature discussing sustainable health care and to identify aspects that pertain to spine surgery.

SUMMARY OF BACKGROUND DATA

In recent years, research has investigated the contribution of surgical specialties to climate change. To our knowledge, no article has yet been published discussing the impact specific to spinal procedures and possible mitigation strategies.

METHODS

A literature search was performed for the present study on relevant terms across four electronic databases. References of included studies were also investigated.

RESULTS

Spine surgery has a growing environmental impact. Investigations of analogous specialties find that procurement is the single largest source of emissions. Carbon-conscious procurement strategies will be needed to mitigate this fully, but clinicians can best reduce their impact by adopting a minimalist approach when using surgical items. Reduced wastage of disposable goods and increased recycling are beneficial. Technology can aid remote access to clinicians, and also enable patient education.

CONCLUSIONS

Spine-surgery-specific research is warranted to evaluate its carbon footprint. A broad range of measures is recommended from preventative medicine to preoperative, intraoperative, and postoperative spine care.

LEVEL OF EVIDENCE

5.

Prevalence of Bacterial Burden on Macroscopic Contaminants of Orthopaedic Surgical Instruments Following Sterilization

BACKGROUND

Macroscopic contamination of orthopaedic instruments with particulates, including cortical bone and polymethyl methacrylate (PMMA) cement, having previously undergone preoperative sterilization, is frequently encountered peri- or intraoperatively, calling into question the sterility of such instruments.

AIM

The purpose of this study is to determine if macroscopic contaminants of orthopaedic surgical instrumentation maintain a bacterial burden following sterile processing. Additionally, this manuscript looks to determine the most commonly contaminated instruments and what the most common contaminants are.

METHODS

At a single tertiary referral centre, we prospectively collected available macroscopic contaminants in orthopaedic instrument trays over a six month period from August 2021 to May 2022. When identified, these specimens were swabbed and plated on sheep blood agar. All specimens were incubated at 37°C for 14 days, and visually inspected for colony formation. When bacterial colony formation was identified, samples were sent for species identification.

RESULTS

A total of 33 contaminants were tested, with only one contaminant growing bacterial colonies which was found to be Corynebacterium. The items most commonly found to have macroscopic contamination were surgical trays (9) and cannulated drills. The identifiable contaminants were bone (10), PMMA bone cement (4), and hair (4). There were 11 macroscopic contaminants that were not identifiable.

CONCLUSION

This study found that 97% of macroscopic orthopaedic surgical instrument contaminants that underwent sterile processing did not possess a bacterial burden. Contaminants discovered during a procedure are likely to be sterile and do not pose a substantially increased risk of infection to a patient.

Reprocessing of loaned surgical instruments/implants in Australia and Brazil: A survey of those at the coalface

BACKGROUND

Acquisition of surgical instruments (SI) and implants by loaner system is a worldwide practice. Although quality of device reprocessing has been reported to be lower in low and middle-income countries compared with higher income countries, few investigations have been conducted on the management and reprocessing of loaned devices. Thus, in this study we evaluate the practices of management and reprocessing of loaner SI and non-sterile implants (NSI) in a high (Australia) and a middle-income (Brazil) country.

METHODS

Cross-sectional surveys (hardcopy or online form) was self-administered by sterilising service unit's personnel of Brazilian and Australian hospitals. Only those units that sourced orthopaedic surgical instruments and non-sterile loaned implants from independent companies were eligible.

RESULTS

A total of 65 questionnaires from Australia and 168 from Brazil were analysed. Quality indicators regarding structure and work process for the management and reprocessing of loaned SI and NSI was of a higher standard in Australia than in Brazil. However, failures were detected in both countries, for instance delivery delays and improper point-of-use pre-cleaning practices.

CONCLUSION

There are key challenges inherent of the multifaceted reusable medical devices loaner system in both countries, such as communication failures, implementation of non-recommended practices, reprocessing of NSI, and other related to structure and process quality indicators, that must be faced. Initial and ongoing education and training should be provided and should embrace the themes of technical proficiency, effective communication and teamwork, and should include all personnel involved in this process, even loaner company staff.

High Prevalence of Biofilms on Retrieved Implants from Aseptic Pseudarthrosis Cases

INTRODUCTION

Recent literature has associated pseudarthrosis and pedicle screw loosening with subchronic infection at the pedicle of the vertebra. The positive culture results of a previous retrieval analysis show that such patients have a high frequency of bacterial contamination. The objective of this study is to visually capture the architecture of these undiagnosed infections, which have been described in other studies as biofilms on supposedly "aseptic" screw loosening.

METHODS

Explants from 10 consecutive patients undergoing revision spine surgery for pseudarthrosis were collected and fixed in glutaraldehyde solution. Each of these implants was imaged thoroughly by using scanning electron microscopy and x-ray spectroscopy to evaluate the architecture of the biofilm. Additionally, eight patient swabs from tissues around the implants were sent for cultures to assess bacterial infiltration in tissues beyond the biofilm. The implants were also analyzed using energy dispersive x-ray spectroscopy. The exclusion criteria included clinically diagnosed infection (current or previous) and/or mechanical failure of the implant due to falls/accidents.

RESULTS

The study was successful in capturing the visual architecture of the biofilm on retrieved implants. A total of 77% of pseudarthrosis cases presented with loose pedicle screws, which were diagnosed by a preoperative computed tomography scan showing radiolucency along the screw track and were confirmed intraoperatively, and 72% of the cases showed biofilm on explants.

CONCLUSIONS

In the absence of the clinical presentation of infection, impregnated bacteria could form a biofilm around an implant, and this biofilm can remain undetected via contemporary diagnostic methods, including swabbing. Implant biofilm is frequently present in "aseptic" pseudarthrosis cases.

Future directions of postoperative spinal implant infections

This article outlines some promising future concepts against postoperative spinal implant infections on the basis of today available literature. The ever-adapting bacteria causing this common complication compel a corresponding continuous research about best effective treatment. The aim is to give a perspective on several future attack-points: surgical infection prevention strategies such as technical optimization of implants and surgical technique; faster diagnostic tools to detect infection, especially in the context of late infections with low-virulent germs and with regard to decision-making in the course of the surgical workflow; and combined surgical and medical treatment options against implant infections. The surgical treatment section will also state open issues concerning implant removal, and the medical treatment section will give an outlook to promising medical alternatives in a post-antibiotic era. To keep up in this field will be important to retain spine surgery in the future as the state-of-the-art treatment option for mandatory spinal interventions in the presence of tumor or trauma and even more so as an attractive option for patients with degenerative spinal disorder for improvement of their life quality.

A Multicenter Trial Demonstrating Presence or Absence of Bacterial Contamination at the Screw-Bone Interface Owing to Absence or Presence of Pedicle Screw Guard, Respectively, During Spinal Fusion

STUDY DESIGN

A prospective multicenter study.

OBJECTIVE

The objective of this study was to assess bacterial contamination in current practices of pedicle screw handling and comparing it to a novel method of using an intraoperative, sterile implant guard for screws.

SUMMARY OF BACKGROUND DATA

Postoperative infections occur at the higher end of 2%-13%, as cited in the literature, and are underestimated due to various reasons in such publications. Despite concerns associated with vancomycin application immediately before closure, it is theoretically impossible to irrigate the screw-bone interface postimplantation. Consequently, any contamination of pedicle screw before implantation is permanent, and has the potential to cause deep-bone infection, or hardware loosening due to encapsulation of biofilm between the bone and the screw. Therefore, continued vigilance and effective preventive measures should be undertaken if available.

MATERIALS AND METHODS

Two groups of presterile individually-packaged pedicle screws, one incased in a sterile, protective guard (group 1: G) and the other without such a guard (group 2: NG), 31 samples in each group were distributed over 28 spinal fusion surgeries at 5 independent hospitals groups. Each were loaded onto the insertion device by the scrub tech and left on the sterile table. Twenty minutes later, the lead surgeon who had just finished preparing the surgical site, handles the pedicle screw, to check the fit with the insertion device. Then, instead of implantation, it was transferred to a sterile container using fresh sterile gloves for bacterial analysis.

RESULTS

The standard unguarded pedicle screws presented bioburden in the range of 10 to 10 colonies forming units per screw, whereas the guarded pedicle screws showed no bioburden.

CONCLUSION

Standard, current, handling of pedicle screws leads to bacterial contamination, which can be avoided if the screws are sterilely prepackaged with an intraoperative guard (preinstalled).

Implant contamination as a cause of surgical site infection in spinal surgery: are single-use implants a reasonable solution? - a systematic review

Background

In spine surgery, surgical site infection (SSI) is one of the main perioperative complications and is associated with a higher patient morbidity and longer patient hospitalization. Most factors associated with SSI are connected with asepsis during the surgical procedure and thus with contamination of implants and instruments used which can be caused by pre- and intraoperative factors. In this systematic review we evaluate the current literature on these causes and discuss possible solutions to avoid implant and instrument contamination.

Methods

A systematic literature search of PubMed addressing implant, instrument and tray contamination in orthopaedic and spinal surgery from 2001 to 2019 was conducted following the PRISMA guidelines. All studies regarding implant and instrument contamination in orthopaedic surgery published in English language were included.

Results

Thirty-five studies were eligible for inclusion and were divided into pre- and intraoperative causes for implant and instrument contamination. Multiple studies showed that reprocessing of medical devices for surgery may be insufficient and lead to surgical site contamination. Regarding intraoperative causes, contamination of gloves and gowns as well as contamination via air are the most striking factors contributing to microbial contamination.

Conclusions

Our systematic literature review shows that multiple factors can lead to instrument or implant contamination. Intraoperative causes of contamination can be avoided by implementing behavior such as changing gloves right before handling an implant and reducing the instruments’ intraoperative exposure to air. In avoidance of preoperative contamination, there still is a lack of convincing evidence for the use of single-use implants in orthopaedic surgery.

Implant Retention or Removal for Management of Surgical Site Infection After Spinal Surgery

STUDY DESIGN

A literature review.

OBJECTIVE

To summarize the implant removal rate, common bacterial organisms found, time of onset, ratio of superficial to deep infection, and regurgitating the prevalence among all the retrospective and prospective studies on management and characterization of surgical site infections (SSIs).

METHODS

PubMed was searched for articles published between 2000 and 2018 on the management or characterization of SSIs after spinal surgery. Only prospective and retrospective studies were included.

RESULTS

A total of 49 articles were found relevant to the objective. These studies highlighted the importance of implant removal to avoid recurrence of SSI. The common organisms detected were methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermis, Staphylococcus epidermis, Staphylococcus aureus, and Propionibacterium acnes, with prevalence of 1% to 15%. A major proportion of all were deep SSI, with minority reporting on late-onset SSI.

CONCLUSION

Long-term antibiotics administration, and continuous irrigation and debridement were common suggestion among the authors; however, the key measure undertaken or implied by most authors to avoid risk of recurrence was removal or replacement of implants for late-onset SSI.

Updates on Evidence-Based Practices to Reduce Preoperative and Intraoperative Contamination of Implants in Spine Surgery: A Narrative Review

The current communication seeks to provide an updated narrative review on latest methods of reducing implant contaminations used during spine surgery. Recent literature review has shown that both preoperative reprocessing and intraoperative handling of implants seem to contaminate implants. In brief, during preoperative phase, the implants undergo repeated bulk cleaning with dirty instruments from the OR, leading to residue buildup at the interfaces and possibly on the surfaces too. This, due to its concealed nature, remains unnoticed by the SPD (sterile processing department) or other hospital staff. Nevertheless, these can be avoided by using individually prepackaged presterilized implants. In the intraoperative phase, the implants (in the sterile field) are directly touched by the scrub tech with soiled (assisting the surgeon dispose the tissues from the instruments in use) gloves for loading onto an insertion device. It is then kept exposed on the working table (either separately or next to the used instruments as the pedicles hole are being prepared). Latest investigation has shown that by the time it is implanted in the patient, it can harbor up to 10e7 bacterial colony-forming units. The same implants were devoid of such colony-forming units, when sheathed by an impermeable sterile sheath around the sterile implant.

Outcomes of an Intraoperative Povidone-Iodine Irrigation Protocol in Spinal Surgery for Surgical Site Infection Prevention

STUDY DESIGN

This was a retrospective observational study.

OBJECTIVE

The aim of this study was to evaluate the efficacy of our new protocol for preventing postoperative surgical site infection (SSI) following spinal surgery.

SUMMARY OF BACKGROUND DATA

SSI following spinal surgery is a serious postoperative complication. Several studies have recently assessed the effectiveness of wound irrigation with povidone-iodine (PVP-I) for SSI prevention, but no consensus has been reached as to how PVP-I should be used in clinical practice. We formed a PVP-I irrigation protocol focusing on the pharmacological properties of PVP-I. This study aimed to evaluate the efficacy and safety of our protocol for preventing SSI.

MATERIALS AND METHODS

All cases of spinal surgery at our hospital between October 2011 and September 2016 were retrospectively reviewed. The exclusion criteria were PVP-I allergy, prior surgical debridement for infection, and implant removal surgery. The patients were subdivided into those who had received normal saline irrigation after 90 seconds of 1% PVP-I pooling every 1.5 hours (study group) or only routine saline irrigation every 1.5 hours (control group). The study and control groups comprised of 177 and 146 patients, respectively. This study compared the rate of SSI with and without the use of the PVP-I irrigation protocol.

RESULTS

The SSI rates were 1.7% for the study group (3/177 patients) and 3.4% for the control group (5/146 patients), showing no significant statistical difference (P=0.32). There were no cases of deep SSI in the study group, whereas there were 4 cases in the control group. The deep SSI rate significantly decreased in the study group (P=0.027). No adverse events occurred in the study group.

CONCLUSION

In this study, 90 seconds of 1% PVP-I pooling every 1.5 hours followed by saline irrigation demonstrated the effectiveness of our protocol for the prevention of postoperative deep SSI after spinal surgery.