Preoperative Sterilization Research Articles

Intraoperative application and early experience with novel high-resolution, high-channel-count thin-film electrodes for human microelectrocorticography.

The study objective was to evaluate intraoperative experience with newly developed high-spatial-resolution microelectrode grids composed of poly(3,4-ethylenedioxythiophene) with polystyrene sulfonate (PEDOT:PSS), and those composed of platinum nanorods (PtNRs). A cohort of patients who underwent craniotomy for pathological tissue resection and who had high-spatial-resolution microelectrode grids placed intraoperatively were evaluated. Patient demographic and baseline clinical variables as well as relevant microelectrode grid characteristic data were collected. The primary and secondary outcome measures of interest were successful microelectrode grid utilization with usable resting-state or task-related data, and grid-related adverse intraoperative events and/or grid dysfunction. Included in the analysis were 89 cases of patients who underwent a craniotomy for resection of neoplasms (n = 58) or epileptogenic tissue (n = 31). These cases accounted for 94 grids: 58 PEDOT:PSS and 36 PtNR grids. Of these 94 grids, 86 were functional and used successfully to obtain cortical recordings from 82 patients. The mean cortical grid recording duration was 15.3 ± 1.15 minutes. Most recordings in patients were obtained during experimental tasks (n = 52, 58.4%), involving language and sensorimotor testing paradigms, or were obtained passively during resting state (n = 32, 36.0%). There were no intraoperative adverse events related to grid placement. However, there were instances of PtNR grid dysfunction (n = 8) related to damage incurred by suboptimal preoperative sterilization (n = 7) and improper handling (n = 1); intraoperative recordings were not performed. Vaporized peroxide sterilization was the most optimal sterilization method for PtNR grids, providing a significantly greater number of usable channels poststerilization than did steam-based sterilization techniques (median 905.0 [IQR 650.8-935.5] vs 356.0 [IQR 18.0-597.8], p = 0.0031). High-spatial-resolution microelectrode grids can be readily incorporated into appropriately selected craniotomy cases for clinical and research purposes. Grids are reliable when preoperative handling and sterilization considerations are accounted for. Future investigations should compare the diagnostic utility of these high-resolution grids to commercially available counterparts and assess whether diagnostic discrepancies relate to clinical outcomes.

Endophthalmitis After Vitreoretinal Surgery

Endophthalmitis after vitreoretinal surgery is uncommon but one of the most serious complications associated with severe visual loss despite appropriate treatment. It can be diagnosed based on symptoms such as ocular pain, conjunctival hyperemia, corneal congestion, corneal edema, anterior chamber inflammation, hypopyon, and vitreous haziness. The most common agents responsible for postoperative endophthalmitis are bacteria from patients' own ocular surface flora. Several factors such as preoperative sterilization, surgical nature of the procedure, intraocular tamponade, and postoperative treatment methods are responsible for the development of endophthalmitis after pars plana vitrectomy. The prognosis of endophthalmitis depends on the virulence of the microorganism, the patients’ immune nature, the time of diagnosis, and the initiation of treatment.

Prevalence of bacterial burden on macroscopic contaminants of orthopaedic surgical instruments following sterilization

Macroscopic contamination of orthopaedic instruments with particulates, including cortical bone and polymethyl methacrylate (PMMA) bone cement, that have previously undergone pre-operative sterilization is frequently encountered peri- or intraoperatively, calling into question the sterility of such instruments. To determine if macroscopic contaminants of orthopaedic surgical instrumentation maintain a bacterial burden following sterile processing, and to determine the most commonly contaminated instruments and the most common contaminants. Macroscopic contaminants in orthopaedic instrument trays were collected prospectively at a single tertiary referral centre over a 6-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 inspected visually for colony formation. When bacterial colony formation was identified, samples were sent for species identification. In total, 33 contaminants were tested, and only one contaminant was found to be growing bacterial colonies (Corynebacterium sp.). The items most commonly found to have macroscopic contamination were surgical trays (N=9) and cannulated drills (N=7). The identifiable contaminants were bone (N=10), PMMA bone cement (N=4) and hair (N=4). Eleven macroscopic contaminants were not identifiable. 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.

Robot-Enabled Uterus Manipulator for Laparoscopic Hysterectomy With Soft RCM Constraints: Design, Control, and Evaluation

Laparoscopic hysterectomy is a common minimally invasive gynecologic surgery in which an assistant is required to manipulate the uterus during the procedure according to the verbal commands of the primary surgeon. However, uterus manipulation is a lengthy and laborious task, where human fatigue may lower operating safety. This paper presents a novel robot-enabled uterus manipulation system that provides accurate, tireless, and direct uterus manipulation. The system consists primarily of a 7-DoF robotic arm tailored for uterus manipulation in laparoscopic hysterectomy. The primary surgeon can directly control the robot using a footswitch pedal to move within the constraint of the Remote Center of Motion (RCM) via software and achieve the desired range of pitch and yaw motion. An additional rotational motion around the instrument axis is provided for twisting the uterus to enhance the exposure of the ligaments and peritoneum for resection. In addition, the robot arm consists of 7 compact modular actuators that provide the target payload for holding the uterus while maintaining a small footprint in a constrained operating environment. To facilitate operation, a passive mobile base is provided for supporting and positioning the robot. A 6-D force sensor is equipped that allows the assistant to quickly guide the robot into the work area and move the robot under RCM constraint using an admittance control approach. The uterus manipulation rod can be easily detached from the robot body by a quick pluggable mechanism for preoperative sterilization. A quick pluggable mechanism was proposed for easy separation and mounting of the uterus manipulation rod from the robot body for preoperative sterilization. Experiments were performed to measure the performance of the modular joints, RCM repeatability, and evaluate the feasibility of the robot in the simulated laparoscopic hysterectomy.

Influence of 3D-printing method, resin material, and sterilization on the accuracy of virtually designed surgical implant guides

Statement of problemThree-dimensional printing has introduced new manufacturing methods. However, information on the influence of the specific printing technology, material, sterilization, and the comparison between printing and milling on the accuracy of surgical guides is lacking. PurposeThe purpose of this in vitro study was to evaluate the influence of the manufacturing method (printing and milling), printing technology stereolithography (SLA) and digital light processing (DLP), material, and sterilization on the accuracy of digitally designed surgical implant guides. Material and methodsResin patient replicas with a single edentulous space were used to place 132 implants with digitally designed surgical guides. The accuracy of postoperative implant position was analyzed for the manufacturing method (printing and milling), resin materials, and preoperative autoclaving. To determine 3D accuracy, angular displacement, mean horizontal crestal, apical displacement, and the linear vertical displacement at the apex were calculated separately for each group (n=12). In addition, the surgical guides were qualitatively analyzed by using field emission scanning electron micrograph. ResultsThe postoperative angular deviation ranged from 0.76 ±0.52 degrees (Rapidshape D20II with NextDent SG) to 2.43 ±0.64 degrees (Form2 with NextDent SG) (P<.001). Linear horizontal displacement at the crest was smallest for Rapidshape D20II with 3Delta Guide (0.27 ±0.08 mm) and highest for Form2 with NextDent SG (0.54 ±0.10 mm) (P<.001). Linear horizontal displacement at the apex ranged from 0.36 ±0.10 mm (SolFlex 350 with V-Print SG) to 0.89 ±0.32 mm (Form2 with NextDent SG) (P<.001). Considering the vertical position displacement was no more than 0.43 ±0.07 mm (Form2 with NextDent SG) short of the apex, none of the implant tips were displaced apically. Preoperative autoclaving differentially impaired the accuracy of surgical guides. ConclusionsThe specific manufacturing technique, the 3D printing device, the resin material, and the application of preoperative sterilization all affected the accuracy of the postoperative implant position. Irrespective of the manufacturing method, all implants were placed within the commonly accepted safety distance.

Effects of Diluents, Saliva and Other Organics on the Microbicidal Activity of Cetylpyridinium Chloride and Povidone-iodine

Povidone-iodine (PVP-I) is used for infection control and preoperative sterilization of the oral and pharyngeal regions. Marketed preparations containing cetylpyridinium chloride (CPC) are used to inhibit growth of oral bacteria. We conducted an in vitro study of the sterilizing effects of these microbicides on 10 oral bacterial strains and fungi related to pneumonia and periodontal disease, after dilution with phosphate-buffered saline (PBS), saliva, and components in saliva. The CPC solution was evaluated at 50 mg/100 mL, which is the concentration used in products. CPC sterilized all strains within 1 minute. Prolongation of the sterilization time associated with dilution was more gradual in comparison to PVP-I solution. CPC sterilized 7 of 10 microbial strains within 3 minutes at 3 mg/100 mL. At 500 mg/100 mL, which is near the upper limit of the concentration that is actually used, PVP-I solution sterilized 7 microbial strains within 3 minutes. However, PVP-I had no sterilization effect when diluted to 100 mg/100 mL or lower. With addition of saliva, PVP-I sterilized 2 microbial strains within 3 minutes at 500 mg/100 mL, whereas CPC solution sterilized 9 microbial strains within 1 minute at 50 mg/100 mL. Our results show that in use influenced by dilution with saliva, CPC is likely to maintain a strong sterilization effect, whereas PVP-I may have a reduced effect.

Preoperative Sterilization Preparation of the Shoulder: A Comparative Study Evaluating Gauze Sponge and Commercially Available Applicator Prep Stick.

Surgical site infection (SSI) remains a concern in shoulder surgery, especially during arthroplasty. While many studies have explored the characteristics and efficacy of different sterilizing solutions, no study has evaluated the method of application. The purpose of this study was to compare two popular pre-surgical preparatory applications (two 4 x 4 cm gauze sponges and applicator stick) in their ability to cover the skin of the shoulder. Two orthopedic surgeons simulated the standard pre-surgical skin preparation on 22 shoulders of volunteer subjects. Each surgeon alternated between an applicator stick and two sterile 4x4 cm gauze sponges. Skin preparation was performed with a commercially available solution that can be illuminated under UV-A light. Advanced image-analysis software was utilized to determine un-prepped areas. A two-tailed paired t-test was performed to compare percentage of un-prepped skin. The applicator stick method resulted in a significantly higher percentage of un-prepped skin (27.25%, Range 10-49.3) than the gauze sponge method (15.37%, Range 5-32.8, P=0.002). Based on image evaluation, most un-prepped areas were present around the axilla. Based on our findings, the use of simple gauze sponges for pre-surgical preparatory application of sterilization solution may result in a lower percent of un-prepped skin than commercially available applicator stick. Orthopaedic surgeons and operating room staff should be careful during the pre-surgical sterile preparation of the shoulder, especially the region around the axilla, in order to reduce the potential risk of surgical site infection.Level of evidence: III.

Seasonality of Infection Rates After Total Joint Arthroplasty

The correlation between season (fall, winter, spring, and summer) and infection rate in surgical patients is well defined in many specialties. To the authors' knowledge, there are no data in the literature on this phenomenon in patients undergoing total joint arthroplasty. They hypothesized that there would be an increased infection rate in the summer months in patients undergoing elective total joint arthroplasty. They retrospectively reviewed consecutive patients undergoing elective total hip or knee arthroplasty at a single institution during 1 year by a single surgeon. Wound infections were defined as any patient requiring oral antibiotics for cellulitis, readmission for intravenous antibiotics, a return to the operating room for irrigation and debridement, or excisional arthroplasty and placement of a cement spacer within 90 days of the initial procedure. Seventeen of 750 patients developed an infection, for an overall incidence of 2.2%. There was a statistically significant difference in infection rate according to season: 3 (1.5%) infections occurred in winter, 1 (0.5%) in spring, 9 (4.7%) in summer, and 4 (2.4%) in fall. The incidence was highest during July (4.5%), August (5.4%), and September (4.3%). There was a statistically significant difference in infection rate between summer/fall (3.6%) vs winter/spring (1.0%). There is an increase in the incidence of infection during summer months for patients undergoing total joint arthroplasty. The authors recommend increased surveillance and more thorough preoperative sterilization procedures during these warmer months.

中耳腔に投与された薬剤の安全性について

A literature review of the safety or ototoxicity of antimicrobials applied to the middle ear cavity was performed. Animal experiments indicated ototoxic effects of otic drops used for the treatment of suppurative otitis media as well as some antiseptic solutions used for preoperative sterilization for the middle ear surgery. Clinical experience indicated fewer adverse effects following the use of antimicrobials and antiseptics in the middle ear cavity, although scant but serious side effects have been reported in the literature. The discrepancy of animal experiment and clinical experience is due largely to the anatomical differences of the cochlea, the round window of rodents are very thin and exposed into the middle ear cavity, whereas that of humans is thick and situated deep in the niche, and often covered with a pseudomembrane.We evaluated the safety of recently marketed eardrops Ofloxacin (OFLX) and Fosfomycin sodium (FOM). Based on the lack of reduction of the compound action potential in guinea pigs, we concluded that there was no ototoxic effect using OFLX or FOM.Also, the ototoxic effect of a Povidone-Iodine preparation was studied. Full strength solution instilled into the middle ear cavity did not cause sensorineural hearing loss at the 24 hours, indicating that rinsing the middle ear cavity with saline during surgery should prevent ototoxic effects of this product.

Antimicrobial efficacy and aqueous humor concentration of preoperative and postoperative topical trimethoprim/polymyxin B sulfate versus tobramycin

We compared trimethoprim sulfate 0.1 %/polymyxin B sulfate 10,000 units/mL with tobramycin 0.3% for preoperative sterilization of the ocular surface, aqueous humor concentration, and ocular safety and comfort in 99 patients who had cataract extraction and intraocular lens implantation. The organisms most frequently cultured from the conjunctiva at baseline were Staphylococcus epidermidis, Corynebacterium species, and Staphylococcus aureus, which were isolated from 66%, 15%, and 8% of the 95 specimens eligible for evaluation. All organisms identified in positive baseline conjunctival cultures except Staphylococcus epidermidis were completely eradicated in both groups on the day of surgery and five to seven days postoperatively. Staphylococcus epidermidis was eradicated on the day of surgery in 58% of patients in the trimethoprim/polymyxin group and in 68% in the tobramycin group. This organism was eradicated five to seven days postoperatively in 85% of patients in both groups. Mean aqueous humor concentration of trimethoprim sulfate at surgery was greater than the mean tobramycin concentration, but neither reached clinically significant inhibitory levels for most organisms. No significant differences were found in ocular safety and comfort.

Cochlear ototoxicity of chlorhexidine gluconate in cats

Chlorhexidine gluconate is a derivative of chlorhexidine and is a popular disinfectant with a strong bactericidal action that is widely used for preoperative sterilization in ear surgery. The purpose of this investigation is to ascertain the potential ototoxicity of this agent. After topically applying chlorhexidine gluconate solutions to the middle ear cavities of 12 cats, we observed the excised cochleas using both scanning and transmission electron microscope studies. Either 0.05% or 2% chlorhexidine gluconate solutions were infused into the right ear of the test animal through one of two tubes chronically installed in the tympanic bullae. The left ears were utilized as controls and were infused with sterilized physiological saline. The solutions were administered once every other day for three separate infusions. Nine animals were decapitated 7 days after the third application, while the other three animals were sacrificed at 4 weeks. In the 2% chlorhexidine group, we found that hair cells in the organ of Corti had degenerated and had lost their hair bundles over a wide range. This pathology was more marked in the lower cochlear turns. In the animals sacrificed at 4 weeks, the injuries present seemed to have progressed. Even at a clinical concentration of 0.05%, chlorhexidine caused intracellular degeneration but with little surface damage. Our findings would suggest a cause of hearing loss when chlorhexidine is used clinically in the ear.

Psychiatric case detection in gynaecological patients.

There is a large and conflicting literature on the frequency and nature of psychiatric disorders in women with gynaecological conditions. It is difficult to interpret and compare the findings of different studies, largely because they have used non-standardised methods of case-identification. The aim of this paper is to illustrate the use of standardised methods of case detection in two gynaecological populations: women undergoing hysterectomy and those receiving elective tubal sterilisation. Three applications of case-identification techniques are described: measuring prevalence; describing features of the disorders; and testing hypotheses. Examples of each are given for the two gynaecological populations.

Development of a canine model for long-term studies after mitral valve replacement with the hall-kaster prosthesis.

The present study was designed for long-term evaluation of the recently developed Hall-Kaster heart valve prosthesis. Mitral valve replacement was performed in 33 dogs. A detailed description of the operative procedure used is given. Extracorporeal circulation was instituted using a nonhemic priming volume resulting in an extreme hemodilution with hematocrit of about 15%. 19 of the animals died within 24 h, while 7 survived the observation period of 4--6 weeks. Thrombus on the valve was the major cause of early and late deaths. Anticoagulants were therefore given, and the therapy was made more extensive as the study progressed. The anticoagulation regime finally comprised warfarin administration preoperatively and throughout the experiment, and heparin infusion during the first 24 h postoperatively. Neomycin was used for preoperative sterilization of the gut. Later, cephalotin and penicillin were given. The use of these anticoagulants and antibiotics was found to be of major significance in providing us with a satisfactory canine model for long-term in vivo evaluation of the prosthesis.

The influence of the surgical technique used for vasectomy on testis function in rats.

Recent studies have suggested that vasectomy can have deleterious effects on testis structure and function in rats. This study investigated the conditions under which the ductus is ligated or removed and the possible effect on testicular activity. 2 groups of rats were sterilized by various operative techniques. The major difference between the groups was in preoperative sterilization procedures for the test subject and operating equipment. The sterile group conditions included aseptic precautions with 70% ethanol which was not part of the procedure in the group. The operative techniques and testis weight and activity ventral prostrate weight and adrenal weight compared and it was found that the groups testicle weights and activity were markedly less than in the sterile group. It is concluded that non-sterile operative procedures led to infection and deterioration of the testis while the sterile group showed no adverse effects on the testis or accessory organs.

Preoperative sterilization of the perineum: a comparison of six antiseptics.

Nine preparations of six antiseptic substances were applied to the perineum of pregnant women at term in order to assess their efficacy in sterilizing the skin. The efficacy, in descending order of effectiveness, after three minutes' exposure, was p-chlor-m-xylenol in alcohol (surgical Dettol); chlorhexidine gluconate in detergent (Hibiscrub), followed by the aqueous preparations p-chlor-m-xylenol (Dettol), chlorhexidine gluconate (Hibitane), cetrimide (Cetavlon), povidoneiodine (Disadine), benzalkonium chloride (Resiguard), and merthiolate. Surgical Dettol was the only alcohol-based preparation used.

Preoperative sterilization technique of the external ear canal.

Bacterial infection following stapedectomy is an undesirable feature. Although such infection happens infrequently, it may cause some of the unexplained cochlear losses. Postoperative occurrence of external otitis, and especially otitis media, have caused perforations of the tympanic membrane and thus have caused failure to close the airbone gap. It is reasonable to assume that most of the postoperative infections could be prevented if the ear canal were to be adequately sterilized prior to surgery. Previous investigators have found that the sterilization technique of the external ear canal prior to stapes surgery resulted only in 40% to 50% effective sterilization, no matter what technique was used. 1,2 These figures were substantiated by our own experiences using the solutions recommended for preoperative sterilization. Because the ear canal cannot be scrubbed effectively, preoperative sterilization is very difficult to obtain. The techniques, using different solutions and methods in scrubbing, cleansing, and irrigating have not

Bacteriology of the healthy conjunctiva.

THE normal bacterial flora of the mucous membranes of the human body have been described for many years and the nature of the common inhabitants is well established; the bacteriological findings in the healthy conjunctiva have been critically surveyed by Duke-Elder (1938). These latter results were obtained in the decades before the use of modern chemotherapeutic drugs for ocular infections became widespread, and it is important to know in what way, if any, such treatment is influencing the commensal organisms of the eye. It has been postulated that the selection pressure due to the use of antibiotics will favour the replacement of bacteria sensitive to these drugs, by strains or mutants which have become, or are, drug-resistant. Recent reports by Gibson (1951) and Barfoed (1953) suggest that these changes may be occurring. In order to determine whether similar changes were happening in London, a survey of the bacterial flora found in 5,000 persons who were admitted for clean surgical procedures was undertaken. From such data it was hoped to determine which single antibiotic, or combination of antibiotics, was most likely to be of use in the pre-operative sterilization of the conjunctiva. Since most of the cultures reported below were taken during the years 1950-51, they do not reflect the effect of the aureomycin-chloramphenicol group which was not in widespread ophthalmic use at that time. Acquired antibiotic resistance was, therefore, restricted to penicillin, streptomycin, and the sulphonamides.

Suppression of the Intestinal Flora in Man by Means of Mixtures of Poorly Absorbed Antibiotics

Summary Mixtures of polymyxin with either neomycin or bacitracin have been shown to suppress effectively the intestinal flora in a series of fourteen patients, with the administration of these drugs by mouth. In the doses used the drugs were poorly, if at all, absorbed from the intestine and no measurable blood levels resulted. Such mixtures are considered safe and practical for pre-operative sterilization of the bowel, reserving systemic antimicrobial agents for the treatment of suspected or established infection. Other areas of possible usefulness of non-absorbable antibiotic mixtures are discussed.

Use of a detergent (pHisoderm) combined with hexachlorophene for skin disinfection.

PREOPERATIVE sterilization of the skin of patient and personnel has been shown to be the weakest link in the chain of sterile technic. 1 This report reviews the results of a clinical trial for one calendar year of a combination of a detergent (pHisoderm®) with a new antiseptic (3 per cent hexachlorophene) for the preoperative sterilization of both the operative field and the hands of the operating personnel. RATIONALE OF EXPERIMENT Previous experimental studies have shown that routine use of hexachlorophene (formerly known as G-11) resulted in a rapid, decided and permanent fall in the resident bacteria of the skin 2 and that the apparent retention of hexachlorophene in the skin resulted in a cumulative bacteriostatic effect on the resident flora. 2b Guild 3 showed that pHisoderm,® a detergent cream composed of a sulfonated ether petrolatum, lactic acid and wool fat cholesterols, possessed active emulsifying, sudsing and dispersing properties with

Mercurochrome and iodine as disinfectants of mucous membrane of mouth Preliminary report on relative effectiveness

The experiments here reported were undertaken with a view of ascertaining the relative efficiency of mercurochrome (especially the 2 per cent aqueous solution) and iodine solutions as disinfectants of the surface of the mucous membranes of the mouth. A further reason has been the general popularity of mercurochrome as a substitute for iodine in preoperative sterilization and for various therapeutic purposes within the oral cavity. Interest in this matter was aroused, indirectly, by the reports of Tinker and Sutton 1 in 1925 and 1926, and of Scott and Hill 2 in 1927, and by a very comprehensive report by Simmons 3 in 1928, all of whom have tested the relative bactericidal action of various mercurochrome solutions and other antiseptics, particularly iodine, from the standpoint of skin disinfection. Tinker and Sutton experimented with a 5 per cent solution of mercurochrome in 50 per cent alcohol, and a 5 per cent alcoholic