Virtual temporal bone simulators and their use in surgical training: a narrative review

OBJECTIVE

Temporal bone dissection is a difficult skill to acquire, and the challenge has recently been further compounded by a reduction in conventional surgical training opportunities during the coronavirus disease 2019 pandemic. Consequently, there has been renewed interest in ear simulation as an adjunct to surgical training for trainees. We review the state-of-the-art virtual temporal bone simulators for surgical training.

MATERIALS AND METHODS

A narrative review of the current literature was performed following a Medline search using a pre-determined search strategy.

RESULTS AND ANALYSIS

Sixty-one studies were included. There are five validated temporal bone simulators: Voxel-Man, CardinalSim, Ohio State University Simulator, Melbourne University's Virtual Reality Surgical Simulation and Visible Ear Simulator. The merits of each have been reviewed, alongside their role in surgical training.

CONCLUSION

Temporal bone simulators have been demonstrated to be useful adjuncts to conventional surgical training methods and are likely to play an increasing role in the future.

National audit of non-melanoma skin cancer excisions performed by plastic surgery in the UK

A national, multi-centre audit of non-melanoma skin cancer excisions by plastic surgery.

Staged upper and lower lip reanimation following facial palsy: Peer-reviewed, patient-rated and objective outcomes

BACKGROUND

One approach to reanimating both upper and lower lips following facial palsy is through staged surgery: cross-face nerve grafting at stage I, free gracilis muscle transfer to levators at stage II and pedicled anterior belly of digastric muscle transfer (ABDMT) to depressors at stage III. The results of this approach were hitherto unquantified.

METHODS

This study retrospectively assessed peer-reviewed, patient-rated and objective outcomes following staged reanimation in adults between 2010 and 2020. Demographics, palsy characteristics and surgery details were recorded. Pre- and postoperative videos were rated by independent assessors using Terzis' aesthetic and symmetry scale. Photographs were analysed using Emotrics and patients completed the Glasgow Benefit Inventory (GBI) patient-rated outcome measure.

RESULTS

Ten patients [mean age = 34 (SD = 12.48)] were eligible. All regained lip elevation and depression. All markers of symmetry improved after gracilis transfer. All markers were also improved after ABDMT except for lower lip height when smiling with teeth showing (p > 0.05). Five patients (50%) responded to the GBI (mean score = +39.44). No patients reported detriment from the reanimations. Mean Terzis' scores preoperatively and after stages II and III were 1.5, 2.26 and 2.39, respectively (p < 0.05). Nine patients underwent aesthetic refinements [lipofilling to lower lip notches (n = 5), debulking of gracilis bulk (n = 6), repositioning of muscle insertion (n = 5) and facelifts (n = 2)].

CONCLUSION

The outcomes were positive objectively and as judged by peers and patients themselves. Aesthetic refinements may also be required to enhance these results.

Lower lip depressor reanimation using anterior belly of digastric muscle transfer improves psychological wellbeing in facial palsy patients

The authors previously published positive peer-reviewed (21 raters using the Terzis scale) and photogrammetric (Emotrics) outcomes in patients who had undergone two-stage lower lip reanimations up to 2018. Other series have published surgeon and peer-rated results, but we know of only two (n=12) that have assessed patients' views using patient satisfaction surveys. This paper presents patient-rated outcomes (PROMS) in an 11-year series of both single and two-stage anterior belly of digastric muscle (ABDM) lower lip reanimations. Demographics, paralysis characteristics, operative details, and complications were recorded. Patients were telephoned and requested to complete the Glasgow Benefit Inventory (GBI) to assess patient-rated outcomes. Thirty-two patients were eligible (mean age 36.4 years). Twenty-one (63.6%) completed the GBI (mean score +33.3). More patients reported benefit than detriment (95.2% vs 4.8%). Complications were infrequent and included three cases of superficial infections and one of dermatitis. Four patients (12.5%) underwent minor revisions, mostly lipofilling of lip notches. The median (range) duration of follow up was 2.8 (0.3 - 8.5) years. ABDM transfer for lower lip reanimation is a safe, low morbidity procedure that enhances the psychological wellbeing of patients with facial palsy.

A 4-year retrospective study of tonsillectomy rate and admission rate of tonsillitis and complications in the East of England and nationally

OBJECTIVES

Guidance set out by Scottish Intercollegiate Guidelines Network (SIGN) sought to restrict the frequency of elective tonsillectomy in reaction to the recognised and substantial risks of the procedure, namely pain and bleeding. With stricter criteria in place before a patient can undergo tonsillectomy, patients must endure more episodes of tonsillitis than was previously the case. The cost of managing tonsillitis and its complications as an inpatient is substantial to the NHS and also to the economy as a whole in missed work days. The authors sought to establish if the reduced rate of tonsillectomy performed had any effect on the rate of acute hospital admission for tonsillitis or the associated abscesses-peritonsillar, parapharyngeal and retropharyngeal.

METHODS

A retrospective multi-centre study reviewed admission data across a 4-year period. The rate of tonsillectomies performed for recurrent tonsillitis across four trusts in Mid-Essex was compared with the number of admissions for tonsillitis, peritonsillar, parapharyngeal and retropharyngeal abscesses. National hospital episode statistics data over a 5-year period was also analysed.

RESULTS

For the regional data in 2015, 979 tonsillectomies were performed across the four centres, reducing to 875 in 2018. There was no trend in the rates of acute tonsillitis requiring admission but the rates of peritonsillar abscess increased from 156 to 192 cases per year in the same period. This correlation was found not to be statistically significant in the measured sample size. The National hospital episode statistics data showed a significant correlation between tonsillectomy rates and admissions from complications of tonsillitis as well as the associated abscesses.

CONCLUSION

This study shows that the reduced tonsillectomy rate was correlated with an increased number of admissions with peritonsillar abscess regionally. Nationally reduced tonsillectomy rate is significantly associated with increased admissions with tonsillitis and all its complications. A decreased rate of tonsillectomy may be increasing the rate of serious tonsillitis. This has an impact on patient morbidity, an increasing financial burden on the NHS and the UK economy.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Field drains as a route of rapid nutrient export from agricultural land receiving biosolids

We report research on the environmental risk of incidental nutrient transfers from land to water for biosolids amended soils. We show that subsurface (drainflow) pathways of P transport may result in significant concentrations, up to 10 mg total P l(-1), in the drainage network of an arable catchment when a P source (recent biosolids application) coincides with a significant and active transport pathway (rainfall event). However, the high P concentrations were short-lived, with drainage ditch total P concentrations returning to pre-storm concentrations within a few days of the storm event. In the case of the drainflow concentrations reported here, the results are unusual in that they describe an 'incidental event' for a groundwater catchment where such events might normally be expected to be rare owing to the capacity of the hydrological system to attenuate nutrient fluxes for highly adsorbed elements such as P. Consequently, there is a potential risk of P transfers to shallow groundwater systems. We suggest that the findings are not specific to biosolids-alone, which is a highly regulated industry, but that similar results may be anticipated had livestock waste or mineral fertilizer been applied, although the magnitude of losses may differ. The risk appears to be more one of timing and the availability of a rapid transport pathway than of P source.

Evaluation of the safety of mixed tocopheryl phosphates (MTP)—A formulation of α-tocopheryl phosphate plus α-di-tocopheryl phosphate

The safety of a formulation of mixed tocopheryl phosphates, (MTP) was evaluated in a series of toxicological tests in vivo using rats, mice and rabbits and in vitro using bacterial and mammalian cell cultures. The tests conducted included an oral LD(50) study, three 28-day oral repeat-dose studies, two dermal toxicity tests, an ocular irritation test, mutagenic potential tests, and chromosomal aberrations tests. MTP consists of mono alpha-tocopheryl phosphate (TP) and di-tocopheryl phosphate (T(2)P) and is intended for use as a dietary supplement and for dermal applications in humans and animals. The dermal and oral LD(50) values of MTP were determined to be >1130 mg/kg bw (918 mg tocopherol equivalents/kg bw) in rabbits and rats, respectively. MTP was not a dermal or eye irritant in rabbits and showed no allergenic potential in mice. In the mutagenicity and genotoxicity studies, MTP did not increased the number of revertants in Salmonella typhimurium or Escherichia coli and did not induce chromosomal aberrations in cultured Chinese hamster ovary (CHO) cells. When administered daily for 28 days by gavage at doses up to 955 mg/kg bw/day (780 mg tocopherol equivalents/kg bw/day), MTP produced no consistent, dose-dependent adverse effects in rats.

Game location and officiating bias in English Club Cricket

One potential contributing factor to the commonly observed home advantage in competitive sport is that officials may be biased in favour of the home team as a result of pressure from spectators. The present study examined officiating behaviour and home advantage, defined as home teams winning over 50% of decided games in English Club Cricket, a sport virtually devoid of spectator influence. Records of game outcomes, as well as dismissals requiring a decision by the umpire, were analysed. The relative frequency of umpiring decisions did not favour either home or away teams. However, a home advantage was found, with the home teams winning 57.1% of decided games (n = 1.449). Considered together, the results suggest that in sports with little or no spectator influence teams may win more often at home for reasons other than biased umpiring decisions, such as familiarity with their home ground or a visiting team's fatigue following travel.

Characterization of chloramphenicol and florfenicol resistance in Escherichia coli associated with bovine diarrhea

Florfenicol, a veterinary fluorinated analog of thiamphenicol, is approved for treatment of bovine respiratory pathogens in the United States. However, florfenicol resistance has recently emerged among veterinary Escherichia coli isolates incriminated in bovine diarrhea. The flo gene, which confers resistance to florfenicol and chloramphenicol, has previously been identified in Photobacterium piscicida and Salmonella enterica serovar Typhimurium DT104. The flo gene product is closely related to the CmlA protein identified in Pseudomonas aeruginosa. The cmlA gene confers nonenzymatic chloramphenicol resistance via an efflux mechanism. Forty-eight E. coli isolates recovered from calves with diarrhea, including 41 that were both chloramphenicol and florfenicol resistant, were assayed for the presence of both flo and cmlA genes. Forty-two of the 44 isolates for which florfenicol MICs were > or =16 microg/ml were positive via PCR for the flo gene. All E. coli isolates for which florfenicol MICs were < or =8 microg/ml were negative for the flo gene (n = 4) Twelve E. coli isolates were positive for cmlA, and chloramphenicol MICs for all 12 were > or =32 microg/ml. Additionally, eight isolates were positive for both flo and cmlA, and both florfenicol and chloramphenicol MICs for these isolates were > or =64 microg/ml. DNA sequence analysis of the E. coli flo gene demonstrated 98% identity to the published GenBank sequences of both serovar Typhimurium flo(St) and P. piscicida pp-flo. The flo gene was identified on high-molecular-weight plasmids of approximately 225 kb among the majority of florfenicol-resistant E. coli isolates. However, not all of the florfenicol-resistant E. coli isolates tested contained the large flo-positive plasmids. This suggests that several of the E. coli isolates may possess a chromosomal flo gene. The E. coli flo gene specifies nonenzymatic cross-resistance to both florfenicol and chloramphenicol, and its presence among bovine E. coli isolates of diverse genetic backgrounds indicates a distribution much wider than previously thought.

Diseases of captive cheetahs (Acinonyx jubatus jubatus) in South Africa: a 20-year retrospective survey

As part of an ongoing study to determine the basis for high prevalences of veno-occlusive disease, glomerulosclerosis, and chronic lymphoplasmacytic gastritis in cheetahs, a retrospective pathology survey of captive cheetahs in the Republic of South Africa (RSA) was conducted. The RSA population was selected because its genetic composition and captive management were similar to those of the cheetah population in U.S. zoos, in which these diseases are common. For this study, archived pathology materials at the University of Pretoria Faculty of Veterinary Sciences in Onderstepoort and the Faculty of Veterinary Science, MEDUNSA, from 69 cheetahs that died between 1975 and 1995 were reviewed, and prevalences of common lesions were compared with those in the U.S. population. Gastritis associated with Helicobacter-like organisms was the most prevalent disease, accounting for close to 40% of the mortalities, including several cheetahs < 3 yr old. Glomerulosclerosis and veno-occlusive disease also were major causes of mortality in RSA cheetahs. RSA cheetahs also had adrenal cortical hyperplasia, cardiac fibrosis, lymphocytic depletion of the spleen, systemic amyloidosis, and splenic myelolipomas. The presence in the captive RSA cheetah population of the same unusual diseases that are common in U.S. cheetahs suggests a species predilection to develop these diseases in captivity.

Development of primers to O-antigen biosynthesis genes for specific detection of Escherichia coli O157 by PCR

The chemical composition of each O-antigen subunit in gram-negative bacteria is a reflection of the unique DNA sequences within each rfb operon. By characterizing DNA sequences contained with each rfb operon, a diagnostic serotype-specific probe to Escherichia coli O serotypes that are commonly associated with bacterial infections can be generated. Recently, from an E. coli O157:H7 cosmid library, O-antigen-positive cosmids were identified with O157-specific antisera. By using the cosmid DNAs as probes, several DNA fragments which were unique to E. coli O157 serotypes were identified by Southern analysis. Several of these DNA fragments were subcloned from O157-antigen-positive cosmids and served as DNA probes in Southern analysis. One DNA fragment within plasmid pDS306 which was specific for E. coli O157 serotypes was identified by Southern analysis. The DNA sequence for this plasmid revealed homology to two rfb genes, the first of which encodes a GDP-mannose dehydratase. These rfb genes were similar to O-antigen biosynthesis genes in Vibrio cholerae and Yersinia enterocolitica serotype O:8. An oligonucleotide primer pair was designed to amplify a 420-bp DNA fragment from E. coli O157 serotypes. The PCR test was specific for E. coli O157 serotypes. PCR detected as few as 10 cells with the O157-specific rfb oligonucleotide primers. Coupled with current enrichment protocols, O157 serotyping by PCR will provide a rapid, specific, and sensitive method for identifying E. coli O157.

Clinical benchmark for healing of chronic venous ulcers. Venous Ulcer Study Collaborators

BACKGROUND

To determine the results of standardized ulcer treatment regimes and effects of the oral thromboxane A2 antagonist Ifetroban (250 mg daily) on healing of chronic lower-extremity venous stasis ulcers.

METHODS

In a prospective, randomized, double blind, placebo-controlled multicenter study, 165 patients were randomized to Ifetroban (n = 83) versus placebo (n = 82) for a period of 12 weeks. Both groups were treated with sustained graduated compression and hydrocolloid. Ulcer size was measured weekly by tracings and computerized planimetry. A total of 150 patients completed the study.

RESULTS

Complete ulcer healing was achieved after 12 weeks in 55% of patients receiving Ifetroban and in 54% of those taking a placebo with no significant differences; 84% of ulcers in both groups achieved greater than 50% area reduction in size.

CONCLUSIONS

These results are likely to be useful as a benchmark for comparison with other treatment protocols concerning the care of chronic lower-extremity stasis ulcers.

Acute and chronic animal models for excessive dermal scarring: quantitative studies

Excessive scarring in the form of keloids and hypertrophic scars continues to be a clinical problem for some patients. The lack of an animal model for such scarring has been an obstacle to studying the cellular and molecular biology of these entities. Previous observations made by the authors that some surgical scars in the rabbit ear remain raised for months after wounding prompted us to investigate whether the rabbit ear might provide a model by which to study excessive dermal scarring. After establishing the model in preliminary study, 40 excisional wounds, 6 mm in diameter, were created over the ventral surface of rabbit ears. Elevated scars were treated with either intralesional triamcinolone acetonide or saline at day 16 postwounding. On day 22, 25 scar wounds were used for thorough histomorphometric analysis, 15 wounds were eliminated prior to analysis because of invagination of epithelial tissue, which made analysis difficult. Total area of scar and Hypertrophic Index, a ratio comparing scar prominence with the thickness of adjacent unwounded tissue, were measured for 25 (62 percent) of the resulting scars. Both total area of scar and Hypertrophic Index were found to be significantly decreased in the steroid-treated group (p < 0.02 and < 0.03, respectively). In a chronic form of this model, in which larger excisions were taken, an excessive accumulation of both new collagen and cartilage over 9 months was observed. An animal model for excessive dermal scarring that allows quantitation of scar formation and, at an early stage, can be modulated in a predictable way with intralesional corticosteroid treatment is presented. This model may parallel hypertrophic scarring in humans and thus might provide a tool by which to study its pathophysiology and objectively evaluate therapeutic modalities.

Topical hydrogen peroxide treatment of ischemic ulcers in the guinea pig: blood recruitment in multiple skin sites

BACKGROUND

Oxygen deficit is a key factor associated with delayed healing of ischemic wounds in human beings. Topical oxygen-releasing compounds such as hydrogen peroxide or tetrachlorodecaoxide have been suggested as therapy for ischemic tissue.

OBJECTIVE

Our purpose was to monitor the effect of hydrogen peroxide cream on the process of ischemic ulcer healing with a model for ischemic ulcers in the guinea pig.

METHODS

Measurement of vascular perfusion with a laser Doppler velocimeter and gross observations of percentage of nonnecrotic wound surface were made on ischemic wounds in guinea pigs after treatment with either a hydrogen peroxide cream or a placebo cream.

RESULTS

Visual evaluations of the percentage of nonnecrotic wound surface showed no statistically significant differences among the treatments. In contrast, vascular perfusion measurements resulted in statistically significant differences. Blood flow was significantly higher up to day 15 in ulcers treated with 2% hydrogen peroxide cream than in those treated with placebo cream. Vascular perfusion was significantly higher in ulcers treated with 3.5% hydrogen peroxide cream than in ulcers treated with either 1.5% hydrogen peroxide cream or placebo. Adjacent control sites in guinea pigs whose ulcers were treated with hydrogen peroxide cream showed increased vascular perfusion compared with corresponding sites in animals whose ulcers were treated with placebo. Even distant flank control sites of ulcers treated with 3.5% hydrogen peroxide cream showed increased vascular perfusion.

CONCLUSION

Treatment of ischemia-induced ulcers with hydrogen peroxide cream enhanced cutaneous blood recruitment not only to ulcers and adjacent sites, but also to distant sites.

Clinical studies and product evaluations: how to maximize their value

Nurses are faced with a panoply of wound care products with minimal scientific research to help them make science-based treatment choices. To aid their decision making, they are encouraged to ask for evidence of product effectiveness/efficacy or to conduct their own study or product evaluation. This article lists reviews of controlled studies on which to base wound care decisions and suggests ways to get the most reliable answers from low-budget trials. It provides wound care professionals with valuable tips on how to make even the simplest product evaluation count as a powerful tool.

Cloning and partial sequencing of an operon encoding two Pseudomonas putida haloalkanoate dehalogenases of opposite stereospecificity

We have cloned fragments of DNA (up to 13 kb), from Pseudomonas putida AJ1, that code for two stereospecific haloalkanoate dehalogenases. These enzymes are highly specific for D and L substrates. The two genes, designated hadD and hadL, have been isolated and independently expressed in Escherichia coli and P. putida hosts by using broad-host-range vectors. They are closely adjacent and inducible in what appears to be an operon with an upstream open reading frame of unknown function. Nucleotide sequence determination of hadD predicts a mature, cytoplasmic protein of 300 amino acid residues (molecular weight of 33,601). This has no significant homology with the L-specific haloalkanoate dehalogenases from Pseudomonas sp. strain CBS3 (B. Schneider, R. Muller, R. Frank, and F. Lingens, J. Bacteriol. 173:1530-1535, 1991) nor with any other known DNA or protein sequences.

Wound dressings: meeting clinical and biological needs

Central to any type of wound therapy is understanding the pathophysiology of healing and danger signals of the most common chronic wounds. This article discusses wound assessment, healing of acute and chronic wounds, factors that retard healing, and summarizes controlled clinical wound dressing literature.

Direct-current bactericidal effect on intact skin

Positive carbon-containing electrodes conveying 5 or more microA of constant direct current per cm2 showed bactericidal activity on intact back skin of 13 human subjects. This effect increased with the duration of stimulation up to a total surface bacterial kill at 20 h. When total current and current density were varied independently on 16 sites on the backs of eight subjects, the effect was dependent on current density, not on total current. Electrodes driven by similar voltages but which removed the electrochemical reaction from inoculated sites on the backs of three subjects failed to reduce the numbers of colony-forming units as compared with those sampled from control sites. This showed the bactericidal effect to be electrochemical in origin, probably mediated by local acidity generated at the surface of the positive carbon-containing electrodes. With an adhesive tape stripping technique on three sites on each of six subjects, it was determined that the effect extended into the epidermis of the human back. No effect was observed beneath negative or control electrodes under the same conditions.

Preparative separation of nucleated cells from human bone marrow

A comparison has been made between the separation of nucleated cells from human bone marrow aspirates by high mol. wt polymers and the buffy coat techniques.