Ultraclean air for prevention of postoperative infection after posterior spinal fusion with instrumentation: a comparison between surgeries performed with and without a vertical exponential filtered air-flow system

ASRA Pain Medicine consensus practice infection control guidelines for regional anesthesia and pain medicine

BACKGROUND

To provide recommendations on risk mitigation, diagnosis and treatment of infectious complications associated with the practice of regional anesthesia, acute and chronic pain management.

METHODS

Following board approval, in 2020 the American Society of Regional Anesthesia and Pain Medicine (ASRA Pain Medicine) commissioned evidence-based guidelines for best practices for infection control. More than 80 research questions were developed and literature searches undertaken by assigned working groups comprising four to five members. Modified US Preventive Services Task Force criteria were used to determine levels of evidence and certainty. Using a modified Delphi method, >50% agreement was needed to accept a recommendation for author review, and >75% agreement for a recommendation to be accepted. The ASRA Pain Medicine Board of Directors reviewed and approved the final guidelines.

RESULTS

After documenting the incidence and infectious complications associated with regional anesthesia and interventional pain procedures including implanted devices, we made recommendations regarding the role of the anesthesiologist and pain physician in infection control, preoperative patient risk factors and management, sterile technique, equipment use and maintenance, healthcare setting (office, hospital, operating room), surgical technique, postoperative risk reduction, and infection symptoms, diagnosis, and treatment. Consensus recommendations were based on risks associated with different settings and procedures, and keeping in mind each patient's unique characteristics.

CONCLUSIONS

The recommendations are intended to be multidisciplinary guidelines for clinical care and clinical decision-making in the regional anesthesia and chronic interventional pain practice. The issues addressed are constantly evolving, therefore, consistent updating will be required.

Bacterial contamination of autologous blood salvaged during deceased donor liver transplantation: a prospective observational study

Decompensated cirrhotic patients experience severely increased intestinal permeability and bacterial translocation. Thus, autologous blood salvaged during deceased donor liver transplantation (DDLT) may be contaminated with enteric bacteria. We aimed to evaluate bacterial contamination of autologous blood salvaged during DDLT and its association with post-transplant bacteremia. In 30 patients undergoing DDLT, bacterial culture was performed in salvaged autologous blood samples: one before graft reperfusion (non-leukoreduced) and two after graft reperfusion (non-leukoreduced and leukoreduced). The primary outcome was bacterial contamination of salvaged autologous blood. Seven of 30 patients (23.3%) were positive for bacteria (3 enteric/4 non-enteric) before graft reperfusion while 11 patients (36.7%) were positive (5 enteric/6 non-enteric) after graft reperfusion. Six of 7 patients who were positive for bacteria before graft reperfusion were positive after graft reperfusion with the same bacteria. Only 4 of 11 contaminated blood samples were converted to negative after leukoreduction. Post-transplant bacteremia risk was insignificantly greater in patients who received autologous blood with bacteria than in patients without bacteria (30.0% vs. 5.0%, P = 0.06). We found contamination of salvaged autologous blood with enteric bacteria throughout DDLT and incomplete performance of leukoreduction, indicating high bacterial load. The potential association between contaminated autotransfusion and post-transplant bacteremia warrants further validation in a larger prospective study.Clinical trial notation: This study was registered at the Clinical Research Information Service (CRiS; https://cris.nih.go.kr ; No. KCT0007223; principal registration investigator: Sangbin Han, date of registration: April 25, 2022).

From basic research to clinical practice: The impact of laminar airflow filters on surgical site infection in vascular surgery

BACKGROUND

Laminar airflow filters have been suggested as a potential preventive factor for surgical site infections, given their ability to reduce the airborne microbiological load. However, their role is still unclear, and evidence regarding vascular surgery patients is scarce. Our aim was to assess the impact of laminar-airflow filters on surgical site infections.

METHODS

This single-centre retrospective cohort study was conducted with vascular surgery patients who underwent arterial vascular intervention through a groin incision between July 2018 and July 2019 (turbulent airflow cohort) and July 2020 and July 2021 (laminar airflow cohort). Data were prospectively collected from electronic medical files. We estimated the cumulative incidence of surgical site infections and its 95% confident interval (95%CI). A propensity score matching analysis was performed.

RESULTS

We included 200 patients, 78 in the turbulent airflow cohort and 122 in the laminar airflow cohort. The cumulative incidence was 15.4% (12/78; 95%CI: 9.0-25.0%) in the turbulent-airflow cohort and 14.8% (18/122; 95%CI: 9.5 -22.1%) in the laminar-airflow cohort (p-value: 1.00). The propensity score matching yielded a cumulative incidence of surgical site infection of 13.9% (10/72) with turbulent airflow and 12.5% (9/72) with laminar airflow (p-value: 1.00). Risk factors associated with infection were chronic kidney disease (OR 2.70; 95%CI: 1.14-6.21) and a greater body mass index (OR 1.47; 95%CI: 1.01-2.14).

CONCLUSION

Laminar airflow filters were associated with a non-significant reduction of surgical site infections. Further research is needed to determine its usefulness and cost-effectiveness. Surgical site infection incidence was associated with chronic kidney disease and a greater body mass index. Hence, efforts should be made to optimize the body mass index before surgery and prevent chronic kidney disease in patients with known arterial disease.

The Neurostimulation Appropriateness Consensus Committee (NACC)®: Recommendations for the Mitigation of Complications of Neurostimulation

INTRODUCTION

The International Neuromodulation Society convened a multispecialty group of physicians based on expertise and international representation to establish evidence-based guidance on the mitigation of neuromodulation complications. This Neurostimulation Appropriateness Consensus Committee (NACC)® project intends to update evidence-based guidance and offer expert opinion that will improve efficacy and safety.

MATERIALS AND METHODS

Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when NACC last published guidelines) to October 2023. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence was scant.

RESULTS

The NACC examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process.

CONCLUSIONS

The NACC recommends best practices regarding the mitigation of complications associated with neurostimulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

Effectiveness of reducing bacterial air contamination when covering sterile goods in the operating room setting: a systematic review and meta-analysis

BACKGROUND

Postoperative surgical site infection is a serious problem. Coverage of sterile goods may be important to protect the goods from bacterial air contamination while awaiting surgery.

AIM

To evaluate the effectiveness of this practice in a systematic review covering five databases using search terms related to bacterial contamination in the operating room and on surgical instruments.

METHODS

MEDLINE, Cochrane, CINAHL, Embase, and Web of Science databases were searched from inception to February 13th, 2023, for randomized and non-randomized controlled studies of covering interventions conducted in the operating room setting. The outcome was bacterial air contamination measured as colony-forming units, and a meta-analysis was performed in separate time periods of coverage. This systematic review and meta-analysis is reported according to the PRISMA statement, and the protocol was prospectively registered in PROSPERO (CRD42022323113). The time points ranged from 30 min to 24 h.

FINDINGS

The results showed that covering sterile goods significantly prevented bacterial air contamination as compared to uncovered goods. The meta-analysis was in favour of covering sterile goods for protection from bacterial air contamination, and showed an effect size Z of 4.76 (P<0.00001; confidence interval: -1.94 to -0.81). The heterogeneity analysis showed a heterogeneity of 83%.

CONCLUSION

No negative effects regarding bacterial contamination were found, and so we conclude that protection with a sterile cover decreases bacterial air contamination of sterile goods while waiting for surgery to start.

Prevention of surgical site infections in pediatric spines: a single-center experience

PURPOSE

To describe the potential issues in the methodology of surgical site infection (SSI) prevention and how it was investigated and corrected in a single institution.

METHODS

A pediatric orthopedic unit experienced an increase of SSI, concerning up to 10% of scoliosis surgery cases from 2011 to 2013. An institutional procedure of multimodal and interdisciplinary risk evaluation was initiated, including a review of the literature, a morbi-mortality meeting, internal and external audits concerning the hygiene conditions in the operating room, the antibiotic prophylaxis, patients, and sterile material pathways. Several preventive actions were implemented, including the improvement of air treatment in the operating room, wound irrigation with 2L of saline before closure, application of topic vancomycine in the wound, verification of doses and timing of antibiotics injection, and use of waterproof bandages. We compared the rates of spine SSI before (retrospective group, 2011-2013) and after the implementation of various preventive measures (prospective group, 2014-2018).

RESULTS

SSI occurred in 12 patients (6 idiopathic and 6 neuromuscular) out of 120 operated on (93 idiopathic, 18 neuromuscular, 9 others) in the retrospective group and 2 (both neuromuscular) out of 196 (150 idiopathic, 33 neuromuscular,13 others) in the prospective group (10% vs 1%, odds ratio=9.7, p=0.001). The groups were comparable for age, etiology, duration of surgery, body mass index, American Society of Anesthesiologists score, number of levels fused, and blood loss (p>0.2).

CONCLUSION

The systematic analysis of SSI allowed for the understanding of the failures and correcting them. The current process is effectively preventing SSI.

LEVEL OF EVIDENCE

3: prospective series with case-control analysis.

Prevention of Surgical Site Infection in Lumbar Instrumented Fusion Using a Sterile Povidone-Iodine Solution

BACKGROUND

Surgical site infection (SSI) is a well-documented complication in patients who undergo posterior spine instrumentation with most studies reporting an incidence of 1%-12%. Some studies have documented that a diluted sterile povidone-iodine (PVI) solution can be safely used in posterior spinal fusion surgeries as an antiseptic; in this study, we analyzed its effectiveness in reducing SSI.

METHODS

This retrospective study consisted of consecutive patients who underwent elective posterior lumbar instrumentation performed by a single surgeon from 2016 to 2019. In the first 134 patients, wounds were irrigated before arthrodesis and closure with 1 L of 0.9% normal saline solution; in the subsequent 144 patients, wound irrigation was with a solution of 35 mL of sterile 10% PVI. Both groups were analyzed to determine if wound irrigation with sterile PVI solution decreased SSIs.

RESULTS

There were 9 (6.7%) SSIs in the 0.9% normal saline solution group versus 1 (0.7%) SSI in the PVI group (P = 0.008). PVI solution had a relative risk for SSI of 0.093 (P = 0.008) and an adjusted odds ratio of 0.113 (P = 0.05). Increased body mass index and posterolateral spine fusion with laminectomy were significant risk factors for SSI (P = 0.04 and P = 0.030, respectively).

CONCLUSIONS

Wound irrigation with PVI solution significantly reduced SSI in elective posterior lumbar instrumentation cases. Subgroup analysis provided significant results to recommend use of PVI solution for SSI prevention, particularly in overweight and obese patients. We also recommend its use in patients with risk factors for SSI, such as longer operative time and unintended durotomy.

Effect of a Clean Surgical Airflow Layer on the Incidence of Infection in Total Hip Arthroplasty

The Center for Health Design estimates that more than 30% of surgical site infections are caused by airborne pathogens. A device that creates a localized clean air field directly adjacent to and surrounding the incision site is meant to shield a surgical site from particulate in the operating room. The purpose of this study was to determine whether the routine use of this device would reduce the rate of infection following total hip arthroplasty (THA). The authors conducted a retrospective review of primary THA cases performed with and without the airflow device. Since July 2013, a total of 1093 primary THA cases were performed with the device at the authors' institution. The incidence of wound dehiscence and deep infection was compared with that of 1171 THA cases performed prior to July 2013 without the airflow device. There were no significant differences between the study groups regarding average patient age, sex, body mass index, or diagnosis. In the airflow group, there were 7 (0.64%) deep infections and 5 (0.46%) cases of wound dehiscence that required a return to the operating room for irrigation and wound revision. In the control group, there were 7 (0.60%) cases of deep infection and 4 (0.34%) wound revisions. The groups were not significantly different in the rates of infection (P=1.0) or wound revision (P=.75). Both groups had a very low incidence of infection and wound revision, with rates below 1%. Despite compelling bench data showing a dramatic reduction of particle load in the wound, the use of the airflow device did not reduce the clinical rate of infection over a large number of cases. [Orthopedics. 2020;43(5):e425-e430.].

Prevención y tratamiento de las infecciones del sitio operatorio en neurocirugía. Estado del arte

El manejo adecuado de las infecciones del sitio operatorio (ISO) en neurocirugía es fundamental para la disminución de la carga de morbilidad y mortalidad en estos pacientes. La sospecha y confirmación diagnóstica asociadas al aislamiento microbiológico son esenciales para asegurar el tratamiento oportuno y el adecuado gerenciamiento de antibióticos. En esta revisión se presenta de forma resumida los puntos fundamentales para la prevención y el tratamiento de infecciones del sitio operatorio en neurocirugía y se incluye un apartado sobre el uso de antibióticos intratecales/intraventriculares.

Laminar Air Flow Handling Systems in the Operating Room

BACKGROUND

Surgical site infection is associated with a substantial healthcare burden and remains one of the most challenging complications to treat. Airborne particles carrying contaminating micro-organisms are responsible for the majority of these infections.

METHODS

Various operating theater ventilatory systems have been developed to prevent direct airborne bacterial inoculation of the surgical wound. Laminar air flow uses positive pressure air currents through filtration units to direct air streams away from the operative field in order to create an ultraclean zone around the operative site.

DISCUSSION

Early studies reported lower infection rates with laminar air flow and therefore it became the accepted standard for implant-related surgery. However, more recent evidence has questioned its clinical importance. The purpose of this article is to review contemporary laminar air flow handling systems and the current evidence behind their use.

Impact of Operating Room Environment on Postoperative Central Nervous System Infection in a Resource-Limited Neurosurgical Center in South Asia

BACKGROUND

Postoperative central nervous system infections (PCNSIs) are serious complications following neurosurgical intervention. We previously investigated the incidence and causative pathogens of PCNSIs at a resource-limited, neurosurgical center in south Asia. This follow-up study was conducted to analyze differences in PCNSIs at the same institution following only one apparent change: the operating room air filtration system.

METHODS

This was a retrospective study of all neurosurgical cases performed between December 1, 2013, and March 31, 2016 at our center. Providers, patient demographic data, case types, perioperative care, rate of PCNSI, and rates of other complications were reviewed. These results were then compared with the findings of our previous study of neurosurgical cases between June 1, 2012, and June 30, 2013.

RESULTS

All 623 neurosurgical operative cases over the study period were reviewed. Four patients (0.6%) had a PCNSI, and no patients had a positive cerebrospinal fluid (CSF) culture. In the previous study, among 363 cases, 71 patients (19.6%) had a PCNSI and 7 (1.9%) had a positive CSF culture (all Gram-negative organisms). The differences in both parameters are statistically significant (P < 0.001). Between the 2 studies, there was no change in treatment providers, case types, case durations, antibiotic administration practices, and patient demographics.

CONCLUSIONS

The rates of PCNSI and positive CSF culture were significantly lower in our present cohort compared with the cohort in our previous study. The sole apparent change involves the air filtration system inside the neurosurgical operating rooms; this environmental change occurred during the 5 months between the 2 studies. This study demonstrates the impact of environmental factors in reducing infections.

Intraoperative Disinfection by Pulse Irrigation with Povidone-Iodine Solution in Spine Surgery

Background

Deep wound infection in spine surgery is a debilitating complication for patients and increases costs. The objective of this prospective study was to evaluate the efficacy of wound pulse irrigation with a dilute povidone-iodine solution in the prevention of surgical site infection.

Methods

50 patients undergoing spinal surgery were randomly divided into two groups (A and B) of 25 patients each. In group A, wounds were irrigated with dilute (3%) povidone-iodine solution through a low-pressure pulsatile device. In group B, wounds were irrigated with saline solution through a bulb syringe. In both groups, specimens for bacterial culture were harvested from surgical site before and after irrigation.

Results

In group A, no surgical site infection occurred; in group B, deep wound infection was observed in 3 patients. In both groups, before irrigation some cultures have been found positive for bacterial contamination.

Conclusion

Our study seems to support the idea that low-pressure pulsating lavage of surgical wounds with povidone-iodine diluted to a nontoxic concentration of 3% is an effective therapeutic adjunct measure to prevent surgical site infection in spine surgery. However, the number of the enrolled patients is small and a significant statistical analysis is not practicable. This trial is registered with NCT03249363.

Effect of laminar airflow ventilation on surgical site infections: a systematic review and meta-analysis

BACKGROUND

The role of the operating room's ventilation system in the prevention of surgical site infections (SSIs) is widely discussed, and existing guidelines do not reflect current evidence. In this context, laminar airflow ventilation was compared with conventional ventilation to assess their effectiveness in reducing the risk of SSIs.

METHODS

We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and WHO regional medical databases from Jan 1, 1990, to Jan 31, 2014. We updated the search for MEDLINE for the period between Feb 1, 2014, and May 25, 2016. We included studies most relevant to our predefined question: is the use of laminar airflow in the operating room associated with the reduction of overall or deep SSI as outcomes in patients of any age undergoing surgical operations? We excluded studies not relevant to the study question, studies not in the selected languages, studies published before Jan 1, 1990, or after May 25, 2016, meeting or conference abstracts, and studies of which the full text was not available. Data were extracted by two independent investigators, with disagreements resolved through further discussion. Authors were contacted if the full-text article was not available, or if important data or information on the paper's content was absent. Studies were assessed for publication bias. Grading of recommendations assessment, development, and evaluation was used to assess the quality of the identified evidence. Meta-analyses were done with RevMan (version 5.3).

FINDINGS

We identified 1947 records of which 12 observational studies were comparing laminar airflow ventilation with conventional turbulent ventilation in orthopaedic, abdominal, and vascular surgery. The meta-analysis of eight cohort studies showed no difference in risk for deep SSIs following total hip arthroplasty (330 146 procedures, odds ratio [OR] 1·29, 95% CI 0·98-1·71; p=0·07, I²=83%). For total knee arthroplasty, the meta-analysis of six cohort studies showed no difference in risk for deep SSIs (134 368 procedures, OR 1·08, 95% CI 0·77-1·52; p=0·65, I²=71%). For abdominal and open vascular surgery, the meta-analysis of three cohort studies found no difference in risk for overall SSIs (63 472 procedures, OR 0·75, 95% CI 0·43-1·33; p=0·33, I²=95%).

INTERPRETATION

The available evidence shows no benefit for laminar airflow compared with conventional turbulent ventilation of the operating room in reducing the risk of SSIs in total hip and knee arthroplasties, and abdominal surgery. Decision makers, medical and administrative, should not regard laminar airflow as a preventive measure to reduce the risk of SSIs. Consequently, this equipment should not be installed in new operating rooms.

FUNDING

None.

The Neurostimulation Appropriateness Consensus Committee (NACC) Recommendations for Infection Prevention and Management

INTRODUCTION

The use of neurostimulation for pain has been an established therapy for many decades and is a major tool in the arsenal to treat neuropathic pain syndromes. Level I evidence has recently been presented to substantiate the therapy, but this is balanced against the risk of complications of an interventional technique.

METHODS

The Neurostimulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society convened an international panel of well published and diverse physicians to examine the best practices for infection mitigation and management in patients undergoing neurostimulation. The NACC recommendations are based on evidence scoring and peer-reviewed literature. Where evidence is lacking the panel added expert opinion to establish recommendations.

RESULTS

The NACC has made recommendations to improve care by reducing infection and managing this complication when it occurs. These evidence-based recommendations should be considered best practices in the clinical implantation of neurostimulation devices.

CONCLUSION

Adhering to established standards can improve patient care and reduce the morbidity and mortality of infectious complications in patients receiving neurostimulation.

Does Minimally Invasive Spine Surgery Minimize Surgical Site Infections?

STUDY DESIGN

Retrospective review of prospectively collected data.

PURPOSE

To evaluate the incidence of surgical site infections (SSIs) in minimally invasive spine surgery (MISS) in a cohort of patients and compare with available historical data on SSI in open spinal surgery cohorts, and to evaluate additional direct costs incurred due to SSI.

OVERVIEW OF LITERATURE

SSI can lead to prolonged antibiotic therapy, extended hospitalization, repeated operations, and implant removal. Small incisions and minimal dissection intrinsic to MISS may minimize the risk of postoperative infections. However, there is a dearth of literature on infections after MISS and their additional direct financial implications.

METHODS

All patients from January 2007 to January 2015 undergoing posterior spinal surgery with tubular retractor system and microscope in our institution were included. The procedures performed included tubular discectomies, tubular decompressions for spinal stenosis and minimal invasive transforaminal lumbar interbody fusion (TLIF). The incidence of postoperative SSI was calculated and compared to the range of cited SSI rates from published studies. Direct costs were calculated from medical billing for index cases and for patients with SSI.

RESULTS

A total of 1,043 patients underwent 763 noninstrumented surgeries (discectomies, decompressions) and 280 instrumented (TLIF) procedures. The mean age was 52.2 years with male:female ratio of 1.08:1. Three infections were encountered with fusion surgeries (mean detection time, 7 days). All three required wound wash and debridement with one patient requiring unilateral implant removal. Additional direct cost due to infection was $2,678 per 100 MISS-TLIF. SSI increased hospital expenditure per patient 1.5-fold after instrumented MISS.

CONCLUSIONS

Overall infection rate after MISS was 0.29%, with SSI rate of 0% in non-instrumented MISS and 1.07% with instrumented MISS. MISS can markedly reduce the SSI rate and can be an effective tool to minimize hospital costs.

Carbon dioxide insufflation deflects airborne particles from an open surgical wound model

BACKGROUND

Surgical site infections remain a significant burden on healthcare systems and may benefit from new countermeasures.

AIM

To assess the merits of open surgical wound CO₂ insufflation via a gas diffuser to reduce airborne contamination, and to determine the distribution of CO₂ in and over a wound.

METHODS

An experimental approach with engineers and clinical researchers was employed to measure the gas flow pattern and motion of airborne particles in a model of an open surgical wound in a simulated theatre setting. Laser-illuminated flow visualizations were performed and the degree of protection was quantified by collecting and characterizing particles deposited in and outside the wound cavity.

FINDINGS

The average number of particles entering the wound with a diameter of <5μm was reduced 1000-fold with 10L/min CO₂ insufflation. Larger and heavier particles had a greater penetration potential and were reduced by a factor of 20. The degree of protection was found to be unaffected by exaggerated movements of hands in and out of the wound cavity. The steady-state CO₂ concentration within the majority of the wound cavity was >95% and diminished rapidly above the wound to an atmospheric level (∼0%) at a height of 25mm.

CONCLUSION

Airborne particles were deflected from entering the wound by the CO₂ in the cavity akin to a protective barrier. Insufflation of CO₂ may be an effective means of reducing intraoperative infection rates in open surgeries.

Evaluation of the Time-dependent Contamination of Spinal Implants: Prospective Randomized Trial

STUDY DESIGN

Prospective study OBJECTIVE.: To evaluate contamination in spinal implants using a liquid culture medium and the effect of covering an implant set on contamination.

SUMMARY OF BACKGROUND DATA

Postoperative infection rates increase with the use of spinal implants. Because implant contamination may be an important origin for postoperative infections, investigation, evaluation, and taking required precautions to prevent these contaminations are critical.

METHODS

Patients operated on for various spinal pathologies were randomized. The patients were divided into groups of covered and uncovered implant sets. The screw samples were placed in liquid culture medium immediately after opening the implant set. The implant set in the covered group was immediately covered with a sterile surgical towel. A new screw was taken from the implant set and cultured in the liquid culture medium every 30 minutes. At the end of 24 hours, swabs with samples from the liquid culture medium were used to culture blood agar. At the end of 48 hours, the samples with growth were considered contaminated.

RESULTS

Growth started after 30 minutes in the uncovered group, whereas only a single growth was noted after 60 minutes in the covered group. Contamination increased with time in both groups, but more so in the open group. A statistically significant difference in contamination was found between the groups at and after 30 minutes.

CONCLUSION

Contamination increases with time in all implant materials. Contamination rates can be reduced by using simple precautions, such as covering the implant set. Culturing the entire implant samples in liquid culture medium is accepted as a safe and more effective method in evaluating contamination.

LEVEL OF EVIDENCE

2.

The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.

METHODS

The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar.

RESULTS

Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated.

CONCLUSIONS

Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

Comparison between mixed and laminar airflow systems in operating rooms and the influence of human factors: experiences from a Swedish orthopedic center

BACKGROUND

The importance of laminar airflow systems in operating rooms as protection from surgical site infections has been questioned. The aim of our study was to explore the differences in air contamination rates between displacement ventilation and laminar airflow systems during planned and acute orthopedic implant surgery. A second aim was to compare the influence of the number of people present, the reasons for traffic flow, and the door-opening rates between the 2 systems.

METHODS

Active air sampling and observations were made during 63 orthopedic implant operations.

RESULTS

The laminar airflow system resulted in a reduction of 89% in colony forming units in comparison with the displacement system (P < .001). The air samples taken in the preparation rooms showed high levels of bacterial growth (≈ 40 CFU/m(3)).

CONCLUSIONS

Our study shows that laminar airflow-ventilated operating rooms offer high-quality air during surgery, with very low levels of colony forming units close to the surgical wound. The continuous maintenance of laminar air flow and other technical systems are crucial, because minor failures in complex systems like those in operating rooms can result in a detrimental effect on air quality and jeopardize the safety of patients. The technical ventilation solutions are important, but they do not guarantee clean air, because many other factors, such as the organization of the work and staff behavior, influence air cleanliness.

Infection with spinal instrumentation: Review of pathogenesis, diagnosis, prevention, and management

Background:

Instrumentation has become an integral component in the management of various spinal pathologies. The rate of infection varies from 2% to 20% of all instrumented spinal procedures. Every occurrence produces patient morbidity, which may adversely affect long-term outcome and increases health care costs.

Methods:

A comprehensive review of the literature from 1990 to 2012 was performed utilizing PubMed and several key words: Infection, spine, instrumentation, implant, management, and biofilms. Articles that provided a current review of the pathogenesis, diagnosis, prevention, and management of instrumented spinal infections over the years were reviewed.

Results:

There are multiple risk factors for postoperative spinal infections. Infections in the setting of instrumentation are more difficult to diagnose and treat due to biofilm. Infections may be early or delayed. C Reactive Protein (CRP) and Magnetic Resonance Imaging (MRI) are important diagnostic tools. Optimal results are obtained with surgical debridement followed by parenteral antibiotics. Removal or replacement of hardware should be considered in delayed infections.

Conclusions:

An improved understanding of the role of biofilm and the development of newer spinal implants has provided insight in the pathogenesis and management of infected spinal implants. This literature review highlights the mechanism, pathogenesis, prevention, and management of infection after spinal instrumentation. It is important to accurately identify and treat postoperative spinal infections. The treatment is often multimodal and prolonged.

Is arthroplasty immediately after an infected case a risk factor for infection?

BACKGROUND

It is common practice in many centers to avoid performing a clean case in a room in which an infected procedure has just taken place. No studies of which we are aware speak to the necessity of this precaution.

QUESTIONS/PURPOSES

The purposes of this study were to identify (1) the risk of infection in a group of patients who underwent arthroplasties performed immediately after a first-stage arthroplasty for joint infection; and (2) the risk of superficial and deep infections in these patients compared with a matched group of patients who underwent arthroplasties not performed after an infected surgery.

METHODS

Eighty-three patients (85 arthroplasties) who underwent arthroplasties (primary or revision) immediately after patients with known infections underwent surgery in the same operating room (OR) were analyzed for 12 months after surgery to determine the incidence of infection. They were matched for demographic factors and surgery type with a control group of 321 patients (354 arthroplasties) who underwent surgery in an OR that had not just been used for surgery involving patients with infections. We compared the risk of superficial and deep infections between the groups.

RESULTS

Patients in the study group were not more likely to have infections develop than those in the control group. One patient in the study group (1.17%) and three in the control group (0.84%) had deep infections develop; the infection in the patient in the study group was caused by a different organism than that of the patient with an infection whose surgery preceded in the OR. Two superficial infections (2.35%) were detected in the study group and 17 (4.8%) were detected in the control group.

CONCLUSIONS

With the numbers available, we found that a deep infection was not more likely to occur in a patient without an infection after an arthroplasty that followed surgery on a patient with an infection than in one who had surgery after a clean case. Although sample size was a potential issue in this study, the results may serve as hypothesis generating for future studies.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Irradiated allograft bone in spine surgery: to culture or not? A single center retrospective study

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

We aimed to document the rate of infection in our institution after the use of irradiated cancellous allograft or iliac crest bone autograft in vertebral fusion procedures. We also reviewed the pertinence of microbiological culture of cadaveric allograft bone prior to its implantation.

SUMMARY OF BACKGROUND DATA

Recent studies have shown similar postoperative infection rates between allograft and autograft. The pertinence of microbiological culture of allograft bone prior to its implantation is currently controversial.

METHODS

Retrospectively, we identified 338 patients who underwent spine fusion procedures for which there was a minimum of a 1-year follow-up. Files from both the neurosurgery and orthopedics divisions of the Centre hospitalier universitaire de Sherbrooke were reviewed during 1999 to 2009. Irradiated allografts were used in 164 patients and autografts were used in 174 patients. Of the 164 allografts implanted, 53 were cultured peroperatively. Postoperative spinal infection was based on documented positive spine cultures at the time of re-exploration for presumed infection. Infection rates were compared using Fisher exact test.

RESULTS

From the 53 peroperative cultures, 5 were positive (9.4%) and none of them led to antibiotherapy or surgical revision at 1 year. No significant difference was observed in the rate of surgical site infection at 1 year, after the use of irradiated allografts (1.8%) or autografts (1.7%), P = 1.0.

CONCLUSION

Perceived association with infection should not influence the surgeon in bone graft choice for spinal fusion. There is a lack of scientific evidence to recommend for or against routine cultures on allograft implantation in the literature. Our results strongly underline the pertinence of larger multicenter clinical trials to assess the pertinence of peroperative allograft bone culture.

The degree of bacterial contamination while performing spine surgery

STUDY DESIGN

Prospective experimental study.

PURPOSE

To evaluate bacterial contamination during surgery.

OVERVIEW OF LITERATURE

The participants of surgery and ventilation system have been known as the most significant sources of contamination.

METHODS

Two pairs of air culture blood agar plate for G(+) bacteria and MacConkey agar plate for G(-) bacteria were placed at 3 different locations in a conventional operation room: in the surgical field, under the airflow of local air conditioner, and pathway to door while performing spine surgeries. One pair of culture plates was retrieved after one hour and the other pair was retrieved after 3 hours. The cultured bacteria were identified and number of colonies was counted.

RESULTS

There was no G(-) bacteria identified. G(+) bacteria grew on all 90 air culture blood agar plates. The colony count of one hour group was 14.5±5.4 in the surgical field, 11.3±6.6 under the local air conditioner, and 13.1±8.7 at the pathway to the door. There was no difference among the 3 locations. The colony count of 3 hours group was 46.4±19.5, 30.3±12.9, and 39.7±15.2, respectively. It was more at the surgical field than under the air conditioner (p=0.03). The number of colonies of one hour group was 13.0±7.0 and 3 hours group was 38.8±17.1. There was positive correlation between the time and the number of colonies (r=0.76, p=0.000).

CONCLUSIONS

Conventional operation room was contaminated by G(+) bacteria. The degree of contamination was most high at the surgical field. The number of bacteria increased right proportionally to the time.

Management of postoperative spinal infections

Postoperative surgical site infection (SSI) is a common complication after posterior lumbar spine surgery. This review details an approach to the prevention, diagnosis and treatment of SSIs. Factors contributing to the development of a SSI can be split into three categories: (1) microbiological factors; (2) factors related to the patient and their spinal pathology; and (3) factors relating to the surgical procedure. SSI is most commonly caused by Staphylococcus aureus. The virulence of the organism causing the SSI can affect its presentation. SSI can be prevented by careful adherence to aseptic technique, prophylactic antibiotics, avoiding myonecrosis by frequently releasing retractors and preoperatively optimizing modifiable patient factors. Increasing pain is commonly the only symptom of a SSI and can lead to a delay in diagnosis. C-reactive protein and magnetic resonance imaging can help establish the diagnosis. Treatment requires acquiring intra-operative cultures to guide future antibiotic therapy and surgical debridement of all necrotic tissue. A SSI can usually be adequately treated without removing spinal instrumentation. A multidisciplinary approach to SSIs is important. It is useful to involve an infectious disease specialist and use minimum serial bactericidal titers to enhance the effectiveness of antibiotic therapy. A plastic surgeon should also be involved in those cases of severe infection that require repeat debridement and delayed closure.

A methodological systematic review on surgical site infections following spinal surgery: part 2: prophylactic treatments

STUDY DESIGN

A methodological systematic review.

OBJECTIVE

To critically appraise the validity of preventive effects attributed to prophylactic treatments for surgical site infection (SSI) after spinal surgery.

SUMMARY OF BACKGROUND DATA

As a result of a rapidly increasing number of spinal procedures, health care expenditure is expected to increase substantially in the foreseeable future. Administration of effective prophylactic treatments may prevent occurrence of SSIs and may thus result in lower costs. To date, however, no review appraising the methodological quality of studies evaluating prophylactic treatments for spinal SSIs has been published.

METHODS

Contemporary studies evaluating the preventive effect of prophylactic interventions on the rate of SSI after spinal surgery were searched through the Medline and EMBASE databases (January 2001 to December 2010). References were retrieved and bias-prone study features were abstracted individually and independently by 2 authors.

RESULTS

Eighteen eligible studies were identified, including 6 randomized controlled trials and 12 comparative cohort studies. Most often, antibiotic prophylaxis administration was investigated (n = 7). Included studies covered a wide variation of indications and surgical procedures. Except for 5 studies (28%), applied definitions of SSI outcomes were ambiguous. Although several important methodological aspects, including blinding of outcome assessors and attrition, were poorly reported in randomized controlled trials, these studies were far less susceptible to bias and confounding as observed in nonrandomized studies. None of the 12 cohort studies adjusted for confounding by matching, stratification, or multivariate regression techniques.

CONCLUSION

Given the plethora of previously hypothesized confounding risk factors for a spinal SSI, conduct of nonrandomized comparative therapeutic studies is strongly discouraged. On the other hand, methodological safeguards, including use of standardized definitions of putative confounders and outcomes, should be considered in more detail during the design phase of a randomized trial.

Traffic flow in the operating room: an explorative and descriptive study on air quality during orthopedic trauma implant surgery

BACKGROUND

Understanding the protective potential of operating room (OR) ventilation under different conditions is crucial to optimizing the surgical environment. This study investigated the air quality, expressed as colony-forming units (CFU)/m(3), during orthopedic trauma surgery in a displacement-ventilated OR; explored how traffic flow and the number of persons present in the OR affects the air contamination rate in the vicinity of surgical wounds; and identified reasons for door openings in the OR.

METHODS

Data collection, consisting of active air sampling and observations, was performed during 30 orthopedic procedures.

RESULTS

In 52 of the 91 air samples collected (57%), the CFU/m(3) values exceeded the recommended level of <10 CFU/m(3). In addition, the data showed a strongly positive correlation between the total CFU/m(3) per operation and total traffic flow per operation (r = 0.74; P = .001; n = 24), after controlling for duration of surgery. A weaker, yet still positive correlation between CFU/m(3) and the number of persons present in the OR (r = 0.22; P = .04; n = 82) was also found. Traffic flow, number of persons present, and duration of surgery explained 68% of the variance in total CFU/m(3) (P = .001).

CONCLUSIONS

Traffic flow has a strong negative impact on the OR environment. The results of this study support interventions aimed at preventing surgical site infections by reducing traffic flow in the OR.

The application of evidence-based measures to reduce surgical site infections during orthopedic surgery - report of a single-center experience in Sweden

Background

Current knowledge suggests that, by applying evidence-based measures relating to the correct use of prophylactic antibiotics, perioperative normothermia, urinary tract catheterization and hand hygiene, important contributions can be made to reducing the risk of postoperative infections and device-related infections. The aim of this study was to explore and describe the application of intraoperative evidence-based measures, designed to reduce the risk of infection. In addition, we aimed to investigate whether the type of surgery, i.e. total joint arthroplasty compared with tibia and femur/hip fracture surgery, affected the use of protective measures.

Method

Data on the clinical application of evidence-based measures were collected structurally on site during 69 consecutively included operations involving fracture surgery (n = 35) and total joint arthroplasties (n = 34) using a pre-tested observation form. For observations in relation to hand disinfection, a modified version of the World Health Organization hand hygiene observation method was used.

Results

In all, only 29 patients (49%) of 59 received prophylaxis within the recommended time span. The differences in the timing of prophylactic antibiotics between total joint arthroplasty and fracture surgery were significant, i.e. a more accurate timing was implemented in patients undergoing total joint arthroplasty (p = 0.02). Eighteen (53%) of the patients undergoing total joint arthroplasty were actively treated with a forced-air warming system. The corresponding number for fracture surgery was 12 (34%) (p = 0.04).

Observations of 254 opportunities for hand hygiene revealed an overall adherence rate of 10.3% to hand disinfection guidelines.

Conclusions

The results showed that the utilization of evidence-based measures to reduce infections in clinical practice is not sufficient and there are unjustifiable differences in care depending on the type of surgery. The poor adherence to hand hygiene precautions in the operating room is a serious problem for patient safety and further studies should focus on resolving this problem. The WHO Safe Surgery checklist “time out” worked as an important reminder, but is not per se a guarantee of safety; it is the way we act in response to mistakes or lapses that finally matters.

Postoperative infections of the lumbar spine: presentation and management

PURPOSE

Postoperative surgical site infections (SSI) are a frequent complication following posterior lumbar spinal surgery. In this manuscript we review strategies for prevention, diagnosis and treatment of SSI.

METHODS

The literature was reviewed using the Pubmed database.

RESULTS

We identified fifty-nine relevant manuscripts almost exclusively composed of Level III and IV studies.

CONCLUSIONS

Risk factors for SSI include: 1) factors related to the nature of the spinal pathology and the surgical procedure and 2) factors related to the systemic health of the patient. Staphylococcus aureus is the most common infectious organism in reported series. Proven methods to prevent SSI include prophylactic antibiotics, meticulous adherence to aseptic technique and frequent release of retractors to prevent myonecrosis. The presentation of SSI is varied depending on the virulence of the infectious organism. Frequently, increasing pain is the only presenting complaint and can lead to a delay in diagnosis. Magnetic resonance imaging and the use of C-reactive protein laboratory studies are useful to establish the diagnosis. Treatment of SSI is centered on surgical debridement of all necrotic tissue and obtaining intra-operative cultures to guide antibiotic therapy. We recommend the involvement of an infectious disease specialist and use of minimum serial bactericidal titers to monitor the efficacy of antibiotic treatment. In the most cases, SSI can be adequately treated while leaving spinal instrumentation in place. For severe SSI, repeat debridement, delayed closure and involvement of a plastic surgeon may be necessary.

Current concepts for clean air and total joint arthroplasty: laminar airflow and ultraviolet radiation: a systematic review

BACKGROUND

With the trend toward pay-for-performance standards plus the increasing incidence and prevalence of periprosthetic joint infection (PJI), orthopaedic surgeons must reconsider all potential infection control measures. Both airborne and nonairborne bacterial contamination must be reduced in the operating room.

QUESTIONS/PURPOSES

Analysis of airborne bacterial reduction technologies includes evaluation of (1) the effectiveness of laminar air flow (LAF) and ultraviolet light (UVL); (2) the financial and potential health costs of each; and (3) an examination of current national and international standards, and guidelines.

METHODS

We systematically reviewed the literature from Ovid, PubMed (Medline), Cochrane DSR, ACP Journal Club, DARE, CCTR, CMR, HTA, NHSEED, CINAHLPLUS, and Google Scholar published until June 2010 focusing on ultraclean air, ultraviolet light, and laminar air.

RESULTS

High-level data demonstrating substantial PJI reduction of any infection control method may not be feasible as a result of the relatively low rates of occurrence and the expense and difficulty of conducting a large enough study with adequate power. UVL has potentially unacceptable health costs and the Centers for Disease Control and Prevention (CDC) recommends against its use. European countries have standardized LAF and it is used by the majority of American joint surgeons.

CONCLUSIONS

Both LAF and UVL reduce PJI. The absence of a high level of evidence from randomized trials is not proof of ineffectiveness. The historically high cost of LAF has decreased substantially. Only LAF has been standardized by several European countries. The CDC recommends further study of LAF but recommends UVL not be used secondary to documented potential health risks to personnel.

Treatment of infections of the spine

Spinal infection may involve the vertebrae, the intervertebral discs, and the adjacent intraspinal and paraspinal soft tissues. It often starts with subtle and insidious clinical signs and symptoms and may development to a debilitating and even life threatening disease. Spinal infections occur with increasing incidence and are nowadays a disease of everyday's practice for physicians treating spinal disorders. Traditionally, conservative treatment consisting of antibiosis and immobilisation is considered the first tier therapy. However, due to a considerably high rate of vertebral column instability or neurological impairment caused by the infected tissue, comprehensive experience with surgical measures have been acquired over the last decades. Thanks to tremendous improvements of surgical implants and techniques, surgical treatment has already begun to challenge conservative treatment to eventually become the first tier therapy for spinal infections in the future. This review seeks to give an overview of epidemiology, pathogenesis, diagnostic evaluation, and current nonsurgical and surgical therapy of spinal infections on the basis of the existing literature, which consists largely of retrospectively acquired data of single-centre experience with sample sizes of less than 100 patients treated with individually defined indications and treatment algorithms, and followed with various outcome parameters.

The influence of perioperative risk factors and therapeutic interventions on infection rates after spine surgery: a systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

The objectives of this systematic review were to determine the patient and perioperative risk factors that contribute to infections after spine surgery and to examine the level of evidence to support the use of therapeutic interventions to reduce infection rates.

SUMMARY OF BACKGROUND DATA

Infection continues to be one of the most common and feared complications after spine surgery. As such, it is used as a sentinel event for quality assurance processes. It is clear that the causes of infections after spine surgery are multifactorial and numerous patient- and procedure-related factors have been proposed as contributory elements. In addition, numerous perioperative adjuncts have been suggested to reduce infection rates.

METHODS

A systematic review of the English-language literature (published between January 1990 and June 2009) was undertaken to identify articles examining risk factors associated with and adjunct treatment measures for preventing surgical-site infections. Two independent reviewers assessed the level of evidence quality using the Grading of Recommendations Assessment, Development, and Evaluation criteria, and disagreements were resolved by consensus.

RESULTS

Of the 127 articles identified, 32 met the criteria to undergo full-text review. Individual patient, operative, and perioperative variables have been identified that are associated with increased infection rates (i.e., older age, obesity, diabetes, malnutrition, higher American Society of Anesthesiologists score, posterior approaches, and blood transfusions) but these variables have not been combined to provide individual patient risks based on a composite of factors (e.g., risk stratification). Of the surgical adjuncts investigated, only irrigation with dilute betadine solution showed moderate support for reducing infection rates.

CONCLUSION

It is clear that the causes of postoperative spinal site infections are multifactorial and related to a complex interplay of patient and procedural influences. Because of these complexities, for any individual and surgical procedure, predictable infection rates likely exist that do not extrapolate to 0. Although we have identified factors associated with increased infection rates, further studies will be required to allow multifactorial risk stratification for individual patients and to further investigate the use of therapeutic adjuncts.

The "six sigma approach" to the operating room environment and infection

The patient's external environment plays a significant, and in some cases dominant, role in his or her infection risk. The use of ultraclean air for certain procedures, as well as avoidance of hypothermia have been proven to reduce the risk of infection. There is no data to support the routine use of surgical masks (by surgeons or staff), ventilating helmets, or routine cleaning of all environmental surfaces in between cases. More research needs to be done in order to determine whether OR design changes, in addition to increasing OR efficiency and thus reducing case times, can also reduce infection rates. Further research is also needed to determine whether or not double gloves and/or the use of antiseptic scrubbing in addition to painting are efficacious.

Postoperative spinal wound infections

Surgical site infection is a common adverse event and a significant source of morbidity after any spinal procedure. A patient who presents with postoperative infection often requires prolonged hospitalization, revision surgical procedures, and long-term intravenous antibiotics. Awareness of risk factors and preventive measures can lead to improved outcomes. Infection after spinal surgery may pose diagnostic challenges and difficult management questions. Postoperative spinal infections present with a diverse degree of severity, from superficial skin incision infections to deep subfascial infections with myonecrosis. Definitive management is based on etiology, clinical course, and patient risk factors.

Surgical revision rates of hooks versus hybrid versus screws versus combined anteroposterior spinal fusion for adolescent idiopathic scoliosis

STUDY DESIGN

Multi-institution retrospective review.

OBJECTIVE

To determine the surgical revision rates of hook, hybrid, anteroposterior, and total pedicle screw constructs for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Much debate continues on the safety, efficacy, and cost of thoracic pedicle screws. Nonetheless, there are no large series that have evaluated the revision rate of various constructs in AIS to determine the need for repeat surgery, and therefore, the added indirect costs and risks of additional procedures.

METHODS

We retrospectively reviewed the surgical case logs of 1428 patients with AIS at 2 institutions from 1990 to 2004, and the clinical records and radiographs of revision cases. Patients were classified into 1 of 4 groups: hook, hybrid hook and screw, all pedicle screw, and combined anteroposterior fusion constructs. Overall, there were 65 (4.6%) returns to the operating room, or 55 (3.9%) cases after excluding infections without concomitant pseudarthrosis.

RESULTS

Of the 65 revision cases, there were 52 females and 13 males, at an average age at first surgery of 13.9 years (range, 9-18 years), and an average age at revision of 14.7 years (range, 12-23 years). For the revision cases, the average initial Cobb was 61.9 degrees (range 44 degrees -110 degrees ), and this was not statistically different within the cohorts (P > 0.05). In terms of revision rate, all hook constructs had a higher revision rate secondary to instrumentation failure when compared with screws, while both hook and hybrid constructs had an overall higher surgical revision rate when compared with screw constructs or anteroposterior constructs (all P <or= 0.05). The pseudarthrosis rate trended toward, but did not meet, statistical significance between these same groups.

CONCLUSION

All pedicle screw and anteroposterior constructs have a lower surgical revision rate when compared with hook and hybrid constructs. The hidden patient and financial costs of these findings should be considered when evaluating overall instrumentation efficacy.

Evaluation of measures to decrease intra-operative bacterial contamination in orthopaedic implant surgery

The aim of this study was to evaluate whether behavioural and systemic measures will decrease intra-operative contamination during total hip or knee replacements. The influence of these measures on subsequent prolonged wound discharge, superficial surgical site infection and deep periprosthetic infection was also investigated during an 18-month follow-up period. Four swabs were taken from instruments at the beginning and end of the procedure for 207 procedures. Removed bone material (acetabulum and femur in case of the hip joint; femur and tibia in case of the knee joint) was also tested for contamination. Initially, 70 operations performed under original control conditions were included, after which the first behavioural measure was introduced (i.e. better use of the plenum). Cultures were taken during 67 operations using better use of the plenum (Group 1), followed by disciplinary measures and the installation of a new laminar flow system. Seventy operations were monitored after this second intervention (Group 2). The control group showed intra-operative contamination in 32.9% (23/70) of cases, Group 1 showed contamination in 34.3% (23/67) of cases and Group 2 showed contamination in 8.6% (6/70) of cases. Prolonged wound discharge and superficial surgical site infection decreased significantly in Group 2, as did the incidence of deep periprosthetic infection; however, the latter did not reach statistical significance. This study shows that the combination of systemic and behavioural changes in an operating room significantly decreases the incidence of intra-operative bacterial contamination, subsequent prolonged wound discharge and superficial surgical site infection. After 18 months of follow-up, there was also a decrease in deep periprosthetic infection.

Laminar air flow provides high air quality in the operating field even during real operating conditions, but personal protection seems to be necessary in operations with tissue combustion

We measured bacterial and particle concentrations at the level of operative fields during 105 operation procedures under laminar air flow conditions. Measured concentrations were at least a factor of 20 lower than in comparable rooms without ultra-clean air and laminar air flow. Kind of operation (septic/aseptic), number of participating persons and quantity of talking seem to have less influence on air quality than presumed, single use cover improves the air quality. The number of ultra-fine and small particles was dramatically increased when tissue was coagulated during operation. This may pose health risks to surgeons and nurses, needs risk assessment and decisions about personal protection.