Table of Instruments

Calibration of an instrumented treatment table for measuring manual therapy forces applied to the cervical spine

SummaryBackgroundAirborne bacteria present in the operating room may be a cause of surgical site infection, either contaminating the surgical wound directly, or indirectly via e.g. surgical instruments. The aim of this study was to evaluate if instrument and assistant tables equipped with local unidirectional airflow reduce bacterial contamination of the instrument area to ultra clean levels, during orthopedic implant surgery in an operating room with displacement ventilation.MethodsLocal airflow units of instrument and assistant tables were either active or inactive. Colony forming units were sampled intraoperatively from the air above the instruments and from instrument dummies. A minimum of three air samples and two-three samples from instrument dummies were taken during each surgery. Samples were incubated on agar for total aerobic bacterial count. The mean air and instrument contamination during each surgery was calculated and used to analyze the difference in contamination depending on use of local airflow or not. All procedures were performed in the same OR.Results188 air and 124 instrument samples were collected during 48 orthopedic implant procedures. Analysis showed that local unidirectional airflow above the surgical instruments significantly reduced the bacterial count in the air above assistant table (P<0.001) and instrument table (P=0.002), as well as on the instrument dummies from the assistant table (P=0.001).ConclusionsInstrumentation tables equipped with local unidirectional airflow protect the surgical instruments from bacterial contamination during orthopedic implant surgery and may therefore reduce the risk of indirect wound contamination.

Effect of using ceiling-mounted systems for imaging in hybrid operating rooms on the level of colony-forming units during surgery

Background:Surgical site infections (SSI) constitute a severe threat to surgery patients. The surgical environment must be as free of contaminating microorganisms as possible. Using sterile surgical instruments while performing surgery is an absolute necessity for ensuring quality of care in perioperative settings.Aim:To compare bacterial contamination of agar plates after 15 h on set surgical instrument tables covered with a single- or double-layer drape.Methods:An experimental design was used consisting of set instrument tables with six agar plates on each table: four instrument tables were covered with a single-layer drape and four instrument tables were covered with a double-layer drape. This set-up was repeated on nine occasions during the period of data collection, making 76 set instrument tables in total. As a control, one instrument table was uncovered on four of those occasions.Results:The double-layer drape cover showed a significantly (P = 0.03) lower number of colony forming units (CFU) per agar plate than the single-layer drape covering. As expected, the uncovered instrument tables were highly contaminated.Discussion:Our results indicate that it is good practice to cover instruments properly with at least a single-layer drape before a surgical procedure. If there is difficulty achieving optimal conditions while setting the instrument tables (e.g. positioning the patient for general anaesthesia), it is a better option to set the instrument tables earlier and cover them with a double-layer drape. These precautions will help protect the patient from harm and unnecessary SSI by lowering microbiological burden, a key factor in developing SSI.

Room air class (RC) Ib may be necessary for surgical procedures in aseptic working areas. The aim of the study was to examine whether a mobile, three-stage sterile ventilation unit (MSVU) can replace a room ventilation system (RVS) with turbulent mixed flow (TMF) in the area of the operating field and on the instrument table from hygienic-microbiological point of view. During 26 surgeries (varicose vein stripping or treatment of umbilical and inguinal hernias), the microbial load was recorded at 4 measuring points (M1-M4) during regular operations by setting up sedimentation plates and measuring the particle concentration. Measuring points M1 and M2 were located at the beginning and the end of the instrument table, measuring point M3 next to the operating field and measuring point M4 outside the sterilely ventilated area approx. 135 cm from the operating field. The measured values were compared with results with simulated, incorrect positioning and with MSVU not switched on. The number of people and the duration of the operation did not differ between the 3 measurement situations.The MSVU achieved a significant reduction in the number of sedimented colony-forming units (CFU) at M1 by 88.4%, at M2 by 91.5% and at M3 by 65.2%. At measuring point M4, the values did not differ between MSVU switched on or off. Even with an unacceptably increased distance between the MSVU and the instrument table, the difference at measuring points M1, M2 and M3 was still significant in comparison with MSVU switched off. Coagulase-negative staphylococci were predominantly detected, followed by Micrococcus luteus and apathogenic spore-forming bacteria, but Gram-negative bacteria were not detected in any cases. The number of CFU detected fulfils the criteria for conventionally turbulent non-directionally ventilated surgical units with TMF of RC Ib.The particle count was reduced by an average of 66%. As comparable particle counts were found in the aseptic working area in a separately conducted study in an RC Ib surgical unit, it can be assumed that the results obtained with the MSVU are hygienically safe. With the MSVU, a reduction of the microbial load and the particle count in the room air was achieved in the area of the operating field and on the instrument table during operation in an RC II surgical unit, which can be categorised as sufficient for operations in RC Ib. With the aid of an MSVU, operations with a high risk of surgical sire infections can also be carried out in surgical units of RC II from hygienic-microbiological point of view. The MSVU is an organisationally flexible and economically interesting, safe and sustainable option in terms of the microbiological load and particle count in the operating field and instrument table instead of an RVS that ventilates the entire room. In times of increasing outpatientisation of surgical services, MSVU is a promising option for outpatient surgical units in particular.

Covering the instrument table decreases bacterial bioburden: An evaluation of environmental quality indicators

BackgroundAir-borne bacteria in the operating room (OR) may contaminate the surgical wound, either by direct sedimentation from the air or indirectly, by contaminated sterile instruments. Reduced air contamination can be achieved with an efficient ventilation system. The current study assesses the additive effect of a mobile laminar airflow (MLAF) unit on the microbiological air quality in an OR supplied with turbulent-mixing air ventilation.MethodsA recently designed OR in NKS (Nya Karolinska Sjukhuset, Stockholm, Sweden) was the physical model for this study. Simulation was made with MLAF units adjacent to the operating table and the instrument tables, in addition to conventional turbulent-mixing ventilation. The evaluation used numerical calculation by computational fluid dynamics (CFD). Sedimentation rates (CFU/m2/h) were calculated above the operating table and two instrument tables, and in the periphery of the OR. Bacterial air contamination (CFU/m3) was simulated above the surgical and instrument tables with and without the MLAF unit.ResultsThe counts of airborne and sedimenting, bacteria-carrying particles downstream of the surgical team were reduced to an acceptable level for orthopedic/implant surgery when the MLAF units were added to conventional OR ventilation. No significant differences in mean sedimentation rates were found in the periphery of the OR.ConclusionsThe MLAF screen unit can be a suitable option when the main OR ventilation system is unable to reduce the level of microbial contamination to an acceptable level for orthopedic implant surgery. However, MLAF effect is limited to an area within 1 m from the screen. Increasing air velocity from the MLAF above 0.4 m/s does not increase the impact area.

ObjectivesIn-depth knowledge about surgical processes is a crucial prerequisite for future systems in operating rooms and the advancement of standards and patient safety in surgery. A holistic approach is required, but research in the field of surgical instrument tables, standardized instrument setups and involved personnel, such as nurses, is sparse in general. The goal of this study is to evaluate whether there is an existing standard within clinics for an instrument table setup. We also evaluate to which extent it is known to the personnel and whether it is accepted.Materials and MethodsThe study makes use of the Nosco Trainer, a scrub nurse training and simulation system developed to analyze various aspects of the workplace of scrub nurses. The system contains a virtual instrument table, which is used to perform and record instrument table setups. We introduce a metric which delivers a measurable score for the similarity of surgical instrument table setups. The study is complemented with a questionnaire covering related aspects.ResultsFifteen scrub nurses of the Otolaryngology departments at three clinics in Germany and Switzerland performed a table setup for a Functional Endoscopic Sinus Surgery intervention and completed the questionnaire. The analysis of the developed metric with a leave one out cross-validation correctly allocated 14 of the 15 participants to their clinic.DiscussionIn contrast to the identified similarities of table setups within clinics with the collected data, only a third of the participants confirmed in the questionnaire that there is an existing table setup standard for Functional Endoscopic Sinus Surgery interventions in their facility, but almost three quarters would support a written standard and acknowledge its possible benefits for trainees and new entrants in the operating room.ConclusionsThe structured analysis of the surgical instrument table using a data-driven metric for comparison is a novel approach to gain deeper knowledge about intra-operative processes. The insights can contribute to patient safety by improving the workflow between surgeon and scrub nurse and also open the way for goal-oriented standardization.

PurposesA septic revision of an artificial joint is routinely split up in a so-called dirty phase and a clean phase. The measures taken to initiate the start of the clean phase vary significantly between musculoskeletal infection centers. We performed simulations of one-step exchanges of infected THAs and sought to 1) determine the effect of different clean phase protocols on the sterile field, and 2) determine whether or not it is possible to re-implant the new prosthesis completely clean.MethodsNine fresh frozen cadaveric hips were used and primary THA was undertaken via a direct anterior approach. Before implantation of the components varying amounts of fluorescent powder (GloGerm) were deposited, simulating bacterial infection. Second, a one-step exchange was performed via a posterolateral approach. After implant removal, debridement, and lavage, randomization determined which clean phase protocol was followed, i.e. no, some or full additional measures. Finally, the new prosthesis was re-implanted.In order to determine the effect of different clean phase protocols on contamination of the sterile field standardized UV light-enhanced photographs were obtained of 1) the gloves, 2) the instrument table, 3) the drapes, and 4) the wound and these were ranked on cleanliness by a blinded panel of hip surgeons.In order to determine whether or not it is possible to re-implant the prosthesis completely clean, the implant was taken out again at the end of the one-step exchange and inspected for contamination under UV light.ResultsThe gloves, the instrument table, the drapes and the wound were significantly cleaner after a clean phase using full additional measures compared to partial or no additional measures (p < 0.000). Partial measures were able to reduce some of the contamination of the gloves and the wound, but had no effect on the drapes and the instrument table. All re-implanted implants were contaminated with some amount of fluorescent powder at the end of the one-step exchange.ConclusionsWe advise to incorporate a clean phase with full additional measures into the surgical treatment of prosthetic joint infections, as partial measures seem to be a poor compromise.Level of evidenceNot applicable (cadaveric study).

Assessment of horizontal laminar air flow instrument table for additional ultraclean space during surgery

The aim of this study is to determine whether the use of a mobile ultra-clean laminar airflow screen reduces the air-borne particle counts in the setting of a simulated procedure of an intra-vitreal injection. A mobile ultra-clean unidirectional airflow (UDF) screen was tested in a simulated procedure for intra-vitreal injections in a treatment room without mechanical ventilation. One UDF was passed over the instrument tray and the surgical area. The concentration of particles was measured in the background, over the instrument table, and next to the ocular area. The degree of protection was calculated at the instrument table and at the surgical site. Use of the UDF mobile screen reduced the mean particle concentration (particles > 0.3 microns) on the instrument table by a factor of at least 100.000 (p < 0.05), and over the patient’s eye by at least a factor of 436 (p < 0.05), which in clinical practice translates into significantly reduced air contamination. Mobile UDF screen reduces the mean particle concentration substantially. The mobile UDF screen may therefore allow for a safer procedural environment for ambulatory care procedures such as intra-vitreal injections in treatment rooms.

Impact of different-sized laminar air flow versus no laminar air flow on bacterial counts in the operating room during orthopedic surgery

The objective of this study is to explore the effects of different room temperatures and different types of activities on the indoor air quality in the operating room during surgery. Three mock-up surgeries were performed at 21 °C, 23 °C, and 25 °C at St. Olavs hospital in Norway. The effects of the surgeon’s activity and nurse's movement on the concentration of particulate matter at the surgical site and instrument table were compared. The results show that the concentrations of particles at both the surgical site and the instrument table are the lowest at room temperature of 23 °C. The activity of the surgeon was the main factor leading to the increase in the concentration of particulate matter with the size 0.3-0.5 μm at the surgical site, while the nurse movement led to the increase in the concentration of particulate matter with the larger size. At all room temperatures, the movement of the distribution nurse had a greater effect than the activity of the surgeon on the increase of the concentration of particles at the instrument table. In addition, the intensity of the particulate source may be factors affecting the concentration of particulate matter. Therefore, it is recommended that distribution nurses should avoid unnecessary activities during the operation.

In the milling process, cutting forces contain key information about the machining process status in terms of workpiece quality and tool condition. On-line cutting force measurement is key for machining condition monitoring and machined surface quality assurance. This paper presents a novel instrumented working table with integrated polyvinylidene fluoride (PVDF) thin-film sensors, thus enabling the dynamic milling force measurement with compact structures. To achieve this, PVDF thin-film sensors are integrated into the working table to sense forces in different directions and the dedicated cutting force decoupling model is derived. A prototype instrumented working table is developed and validated. The validation demonstrates that profiles of the forces measured from the developed instrumented working table prototype and the dynamometer match well. Furthermore, the milling experiment results convey that the instrumented working table prototype could also identify the tool runout due to tool manufacturing or assembly errors, and the force signal spectrum analysis indicates that the developed working table can capture the tool passing frequency correctly, therefore, is suitable for the milling force measurement.

A mobile laminar airflow unit to reduce air bacterial contamination at surgical area in a conventionally ventilated operating theatre