Impact of the COVID-19 pandemic on management and outcomes in acute appendicitis: Should these new practices be the norm?

Background

In early 2020, the COVID-19 pandemic significantly altered management of surgical patients globally. International guidelines recommended that non-operative management be implemented wherever possible (e.g. in proven uncomplicated appendicitis) to reduce pressure on healthcare services and reduce risk of peri-operative viral transmission. We sought to compare our management and outcomes of appendicitis during lockdown vs a non-pandemic period.

Methods

All presentations to our department with a clinical diagnosis of acute appendicitis between 12/03/2020 and 30/06/2020 were compared to the same 110-day period in 2019. Quantity and severity of presentations, use of radiological investigations, rate of operative intervention and histopathological findings were variables collected for comparison.

Results

There was a reduction in appendicitis presentations (from 74 to 56 cases), and an increase in radiological imaging (from 70.27% to 89.29%) (P = 0.007) from 2019 to 2020. In 2019, 93.24% of patients had appendicectomy, compared to 71.42% in 2020(P < 0.001). This decrease was most pronounced in uncomplicated cases, whose operative rates dropped from 90.32% to 62.5% (P = 0.009). Post-operative histology confirmed appendicitis in 73.9% in 2019, compared to 97.5% in 2020 (P = 0.001). Normal appendiceal pathology was reported for 17 cases (24.64%) in 2019, compared to none in 2020 (P < 0.001) – a 0% negative appendicectomy rate (NAR).

Discussion

The 0% NAR in 2020 is due to a combination of increased CT imaging, a higher threshold to operate, and is impacted by increased disease severity due to delayed patient presentation. This study adds to growing literature promoting routine use of radiological imaging to confirm appendicitis diagnosis. As we enter a second lockdown, patients should be encouraged to avoid late presentations, and surgical departments should continue using radiological imaging more liberally in guiding appendicitis management.

The Effect of Various Methods of Eye Immobilization on Corneal Topography

BACKGROUND

Accurate, predictable, and safe refractive surgery requires immobilization of the eye. We measured the effects of current eye fixation techniques on human cadaver eyes.

MATERIALS AND METHODS

Central to our study was a device specially designed to secure cadaver eyes and stabilize intraocular pressure. Topographical measurements were made with a modified Model 2 Corneal Analysis System (EyeSys Technologies, Houston, Tex) mounted vertically to allow analysis of a cadaver eye mounted in the artificial orbit. The effect on human cadaver eyes of six fixation instruments was assessed: forceps, U-shaped fixation forceps, a full Hofman-Thornton ring, a VISX vacuum fixation ring, a Meditec suction ring, and a new instrument, the Eye Fixation Speculum.

RESULTS

The circular vacuum fixation rings caused minimal distortion, resulting in less than 1.00 diopter (D) of change. Forceps and U-shaped fixation forceps, which apply force at one or two points, caused significantly more distortion. Single-point fixation forceps distorted the cornea at the point of application a mean of +5.50 +/- 3.50 D, and, at 180 degrees from the point of instrument application, a mean of +2.00 +/- 1.90 D. U-shaped forceps apply force at two points, 90 degrees and 270 degrees, from the axis of instrument application. At these axes, the cornea was distorted a mean of +9.40 +/- 3.70 D and +8.30 +/- 3.10 D, respectively.

CONCLUSIONS

Single- and multi-point fixation instruments, due to an asymmetric application of fixation force, significantly distort the cornea. Ring fixation instruments, which apply a more equally distributed force, cause less distortion.

193-nm excimer photorefractive keratectomy in high myopia

PURPOSE

To evaluate the refractive results of 193-nm excimer laser photorefractive keratectomy (PRK) performed on 48 highly myopic eyes in a multicenter study.

METHODS

A Visx 2015 or 2000 argon-fluoride excimer laser and a single-zone ablation technique were used. Postoperatively, eyes were treated with topical fluoromethalone for up to 5 months. Most eyes were treated with a 6.0- to 6.2-mm beam diameter after undercorrections and increased regression were noted with a 5.5-mm beam in earlier studies. Forty-eight eyes were treated for myopia, which was between -8.0 and -15.25 diopters (D) (spherical equivalent). The mean preoperative refraction was -11.2 D. Retreatment was performed after 6 to 16 months on 11 eyes for undercorrection. All eyes not retreated were followed for at least 12 months.

RESULTS

At 6 months, follow-up was available on 47 eyes. Of these eyes, 40% and 64% achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 60% of eyes attained 20/40 visual acuity or better uncorrected. Eleven patients (23%) were retreated between 6 to 16 months for undercorrection and/or regression. After retreatment, 47% and 81% of eyes achieved corrections within 1 and 2 D of attempted correction, respectively. At 1 year, 15% of eyes lost two lines of best-corrected visual acuity, and no eyes lost more than two lines. There was slightly more corneal haze seen in this group compared with the haze seen in patients undergoing PRK for low and moderate myopia.

CONCLUSIONS

These data show that excimer PRK can correct high amounts of myopia with reasonable stability after 6 months. Excimer PRK is an effective surgical treatment of severe myopia, but long-term follow-up is still needed to assess the stability of its effect.

Genetic analysis of Hispanic individuals with cystic fibrosis

We have performed molecular genetic analyses of Hispanic individuals with cystic fibrosis (CF) in the southwestern United States. Of 129 CF chromosomes analyzed, only 46% (59/129) carry delta F508. The G542X mutation was found on 5% (7/129) of CF chromosomes. The 3849 + 10kbC-->T mutation, detected primarily in Ashkenazi Jews, was present on 2% (3/129). R1162X and R334W, mutations identified in Spain and Italy, each occurred on 1.6% (2/129) of CF chromosomes. W1282X and R553X were each detected once. G551D and N1303K were not found. Overall, screening for 22 or more mutations resulted in detection of only 58% of CF transmembrane conductance regulator gene mutations among Hispanic individuals. Analysis of KM19/XV2c haplotypes revealed an unusual distribution. Although the majority of delta F508 mutations are on chromosomes of B haplotypes, the other CF mutations are on A and C haplotypes at higher-than-expected frequencies. These genetic analyses demonstrate significant differences between Hispanic individuals with CF and those of the general North American population. Assessment of carrier/affected risk in Hispanic CF individuals cannot, therefore, be based on the mutation frequencies found through studies of the general population but must be adjusted to better reflect the genetic makeup of this ethnic group. Further studies are necessary to identify the causative mutation(s) in this population and to better delineate genotype/phenotype correlations. These will enable counselors to provide more accurate genetic counseling.

Difference in frequencies of the cystic fibrosis alleles, delta F508 and W1282X, between carriers and patients

One major mutation, delta F508, causing cystic fibrosis (CF) is found in most populations around the world. Among CF patients of Jewish Ashkenazi origin two major mutations, W1282X and delta F508 were found. We compared the relative frequencies of the two major mutations found in this patient population to their relative frequencies in the healthy population. The studied patient population included the entire CF Jewish Ashkenazi patient population in Israel (238 chromosomes), and a small group of Jewish Ashkenazi patients in the USA (57 chromosomes). Among these, 79 (27%) chromosomes carried the delta F508 mutation, and 151 (51%) the W1282X mutation. In addition, we have analyzed the results of screening 1,946 unrelated healthy Jewish Ashkenazi individuals for the delta F508 and the W1282X mutations. Surprisingly, an almost equal number of carriers of the delta F508 (35) and W1282X (36) was found. The difference between the relative proportions of the mutations in the two groups is statistically significant (p = 0.025). A striking manifestation of this difference is revealed in the analysis of patients' genotypes. There were 36 patients homozygous for W1282X, while only 7 patients were homozygous for delta F508, although the number of delta F508 carriers in the general Jewish Ashkenazi population is almost equal to the number of W1282X carriers. This difference in allele frequencies found between healthy carriers and CF patients in the Jewish Ashkenazi population might not be unique to this ethnic group nor to the CF disease. The results indicate that the common practice of inferring general population epidemiologic parameters directly from patients information is liable to introduce biases.(ABSTRACT TRUNCATED AT 250 WORDS)

Topical diclofenac in the treatment of ocular pain after excimer photorefractive keratectomy

BACKGROUND

Following excimer laser photorefractive keratectomy, patients experience significant ocular pain until corneal reepithelialization. Despite the use of cold compresses, bandage soft contact lenses, cycloplegics, narcotics, and topical corticosteroids, the pain has not been adequately controlled in many patients.

METHODS

A randomized, double-masked, parallel-group study of diclofenac sodium 0.1% ophthalmic solution and its placebo vehicle was evaluated. Patients undergoing excimer myopic photorefractive keratectomy on their second eye were admitted overnight. Postoperative procedures included two drops of diclofenac or placebo immediately after surgery and then qid until reepithelialization, topical tobramycin (qid), 0.1% fluorometholone (q2h), cycloplegics, and a disposable soft contact lens. Thirty-two patients (diclofenac = 16, placebo = 16) were evaluated from +30 minutes to +96 hours by several types of questionnaires.

RESULTS

Most patients who received placebo experienced pain, starting within 1 hour, peaking at 4 to 6 hours and lasting 36 to 48 hours. The diclofenac-treated patients rarely experienced the early peak in pain, had less pain overall until 72 hours postoperatively, and experienced significantly less photophobia and burning/stinging. Significantly fewer patients on diclofenac required oral narcotics. Three patients (diclofenac = 2, placebo = 1) developed corneal infiltrates, the etiology of which is not known. In a separate study we conducted, there was no difference in epithelial healing times between the diclofenac-treated eyes and those not receiving the drug.

CONCLUSIONS

Diclofenac appears to significantly reduce the ocular pain following excimer photorefractive keratectomy.

Excimer laser photorefractive keratectomy in high myopia. A multicenter study

Excimer photorefractive keratectomy was performed at three centers on 16 highly myopic eyes (8 diopters [D] or more) and followed up for 6 months. Ablation depths ranged from 137 to 230 microns. The preoperative spherical equivalent of myopia ranged from -8.62 D to -14.50 D (mean +/- SD, -11.57 +/- 1.62 D). Six months after surgery, the mean refraction (spherical equivalent) was -0.90 +/- 2.13 D. Eleven of 16 eyes achieved refractions within 2 D of that attempted. All eight patients at one site were treated with a maximum-beam diameter of 6.0 mm and were corrected to within 2 D of that attempted, and all were 20/40 or better uncorrected. Three of eight eyes at the other two sites were treated with a 5.5- or 5.6-mm maximum-beam diameter, which achieved corrections within 2 D of that attempted. The epithelium healed within 3 to 4 days, and there were no erosions. Mild subepithelial reticular haze, similar to that seen with excimer photorefractive keratectomy for lower myopia, was seen in all patients, with two patients experiencing more significant corneal haze. This peaked at 3 to 6 weeks and then gradually diminished. All but two patients had a return of their best corrected preoperative visual acuity to within one Snellen line at 6 months. This preliminary study shows excimer photorefractive keratectomy to be a promising surgical treatment for patients with higher myopia.

Excimer laser photorefractive keratectomy in high myopia: a multicenter study

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Proteins specified by the short unique region of the genome of pseudorabies virus play a role in the release of virions from certain cells

Two pseudorabies virus vaccine strains (Bartha and Norden) that have a similar deletion in the short unique (Us) region of the genome have been identified previously (B. Lomniczi, M. L. Blankenship, and T. Ben-Porat, J. Virol. 49:970-979, 1984). These strains do not code for the glycoprotein gI, a glycoprotein that has been mapped on the wild type virus genome by T. C. Mettenleiter, N. Lukacs, and H. J. Rziha (J. Virol. 53:52-57, 1985) to the sequences deleted from the vaccine strain. Restoration of these deleted sequences to the Bartha strain genome restores to the virus the ability to specify the gI glycoprotein. The Bartha vaccine strain grows as well as wild-type virus in pig kidney and in rabbit kidney (RK) cells, but is not released efficiently from and forms small plaques in RK cells. The rescued Bartha 43/25a strain (which has an intact Us) is released considerably more efficiently than the Bartha vaccine strain, but less efficiently than wild-type virus from RK cells; it also forms larger plaques on RK cells than does the parental Bartha vaccine strain. The Norden vaccine strain, which has a deletion in the Us, is released better from RK cells than is the Bartha strain, but not as well as is wild-type virus. We conclude that whereas the sequences in the Us that are deleted from the Bartha and Norden strain genomes specify functions that play a role in the release of virions from some cell types, at least one other function (which is defective in the Bartha strain but not in the Norden strain) also affects release of virus from these cells. Since restoration to the Bartha strain of an intact Us restores to the virus both the ability to grow in chicken brains (B. Lomniczi, S. Watanabe, T. Ben-Porat, and A. S. Kaplan, J. Virol. 52:198-205, 1984) and to be released from RK cells, the possibility that the lack of virulence of the Bartha vaccine strain may be related to its limited release from some target cells is discussed.