Observed rates of surgical instrument errors point to visualization tasks as being a critically vulnerable point in sterile processing and a significant cause of lost chargeable OR minutes

BACKGROUND

The reporting of surgical instrument errors historically relies on cumbersome, non-automated, human-dependent, data entry into a computer database that is not integrated into the electronic medical record. The limitations of these reporting systems make it difficult to accurately estimate the negative impact of surgical instrument errors on operating room efficiencies. We set out to determine the impact of surgical instrument errors on a two-hospital healthcare campus using independent observers trained in the identification of Surgical Instrument Errors.

METHODS

This study was conducted in the 7 pediatric ORs at an academic healthcare campus. Direct observations were conducted over the summer of 2021 in the 7 pediatric ORs by 24 trained student observers during elective OR days. Surgical service line, error type, case type (inpatient or outpatient), and associated length of delay were recorded.

RESULTS

There were 236 observed errors affecting 147 individual surgical cases. The three most common errors were Missing+ (n = 160), Broken/poorly functioning instruments (n = 44), and Tray+ (n = 13). Errors arising from failures in visualization (i.e. inspection, identification, function) accounted for 88.6% of all errors (Missing+/Broken/Bioburden). Significantly more inpatient cases (42.73%) had errors than outpatient cases (22.32%) (p = 0.0129). For cases in which data was collected on whether an error caused a delay (103), over 50% of both IP and OP cases experienced a delay. The average length of delays per case was 10.16 min. The annual lost charges in dollars for surgical instrument associated delays in chargeable minutes was estimated to be between $6,751,058.06 and $9,421,590.11.

CONCLUSIONS

These data indicate that elimination of surgical instrument errors should be a major target of waste reduction. Most observed errors (88.6%) have to do with failures in the visualization required to identify, determine functionality, detect the presence of bioburden, and assemble instruments into the correct trays. To reduce these errors and associated waste, technological advances in instrument identification, inspection, and assembly will need to be made and applied to the process of sterile processing.

Using Preference Cards to Support a Thoughtful, Evidence-based Orthopaedic Surgery Practice

INTRODUCTION

When orthopaedic surgeons begin or relocate their careers, they must communicate effectively about their instrumentation and equipment needs. 'Preference Cards' or 'Pick Lists' are generated by and for individual surgeons at the time of hire and can be updated over time to reflect their needs for common cases. Currently, such decisions are made without formal guidance or preparation.

BODY

Surgeons must consider and plan for their operating room needs. Health system and industry factors affect these decisions, as do surgeons' unique interests, preferences, and biases. Orthopaedic surgeons currently face challenges: formal education is deficient in this space, material and reprocessing costs are not transparent, relationships and contracts with industry are complex, and few health systems have mechanisms to support preference card optimization. This complex landscape influences utilization decisions and leaves opportunities for integration, collaboration, and innovation.

SUMMARY

Choices about instrument and resource utilization in the OR have wide-reaching impacts on costs, waste generation, OR efficiency, sterile processing, and industry trends. Surgeons and their teams have much to gain by making intentional choices and pursuing both individual and systematic improvements in this space.

Introduction of pediatric laparoscopic inguinal hernia repair in Guatemala

PURPOSE

Introducing new surgical techniques in a developing country can be challenging. Inguinal hernias in children are a common surgical problem, and open repair is the standard surgical approach. Laparoscopic repair has gained popularity in developed countries because of similar results. This study aimed to determine the outcomes following the introduction of laparoscopic repairs in Guatemala.

METHODS

This retrospective analysis of prospectively collected data from all patients under 18 years who underwent laparoscopic repair at Corpus Christi Hospital in Patzun, Guatemala, from September 5th to September 8th, 2022.

RESULTS

A total of 14 patients were included in the study. A board-certified pediatric surgeon and a Guatemalan physician performed all cases. The mean patient age was 7.6 years; 7 boys and 7 girls. All patients were interviewed at 7 days, 30 days, and 6 months. There were no postoperative infections, pain requiring re-evaluation, gonadal atrophy, or hernia recurrence.

CONCLUSION

Under controlled circumstances with limited but proper equipment and disposables, laparoscopic inguinal hernia repairs can be introduced and performed in a developing country with a risk complication profile comparable to that in developed countries. This study provides promising evidence of laparoscopic repair feasibility and safety where surgical resources are limited.

Intercostal nerve cryoablation is associated with lower hospital cost during minimally invasive Nuss procedure for pectus excavatum

Minimally invasive repair of pectus excavatum (Nuss procedure) is associated with significant pain, and efforts to control pain impact resource utilization. Bilateral thoracic intercostal nerve cryoablation has been proposed as a novel technique to improve post-operative pain control, though the impact on hospital cost is unknown.

METHODS

We conducted a retrospective study of patients undergoing a Nuss procedure from 2016 to 2019. Patients who received cryoablation were compared to those that received traditional pain control (patient-controlled analgesia or epidural). Outcome variables included postoperative opioid usage (milligram morphine equivalents, MME), length of stay (LOS), and hospital cost.

RESULTS

Thirty-five of 73 patients studied (48%) received intercostal nerve cryoablation. LOS (1.0 vs 4.0 days, p < 0.01) and total hospital cost ($21,924 versus $23,694, p = 0.04) were decreased in the cryoablation cohort, despite longer operative time (152 vs 74 min, p < 0.01). Cryoablation was associated with decreased opioid usage (15.0 versus 148.6 MME, p < 0.01) during the 24 h following surgery and this persisted over the entire postoperative period, including discharge opioid prescription (112.5 vs 300.0 MME, p < 0.01).

CONCLUSION

Bilateral intercostal nerve cryoablation is associated with decreased postoperative opioid usage and decreased resource utilization in pediatric patients undergoing a minimally invasive Nuss procedure for pectus excavatum.

LEVEL OF EVIDENCE

Retrospective comparative study, level III.

Reducing cost and waste in pediatric laparoscopic procedures

BACKGROUND

In 2017 the healthcare cost in the United States accounted for 17.9% of the Gross Domestic Product (GDP). Furthermore, healthcare facilities produce more than 4 billion pounds of waste annually. Interhospital and intersurgeon variabilities in surgical procedures are some of the drivers of high healthcare cost and waste. We sought to determine the effect of a monthly surgeon report card detailing the utilization and cost of disposable and reusable surgical supplies on cost and waste reduction for pediatric laparoscopic procedures.

METHODS

Starting in July 2017, surgeons were provided with an individual report with supply cost per case, high cost, and disposable supply utilization, and clinical outcomes. Cost, utilization, and clinical outcomes six quarters before and after the intervention were compared.

RESULTS

A total of 998 pediatric laparoscopic procedures were analyzed. We reduced the median supply cost per case by 43% after the intervention with total cost savings of $71,035 for the first four quarters. We also reduced the use of disposable trocars by 56% and the use of disposable harmonics and staplers by 33%.

CONCLUSIONS

Using a periodic surgeon report card, we significantly reduced supply cost and utilization of disposable items for all pediatric laparoscopic procedures performed at the University of Wisconsin American Family Children's Hospital.

TYPE OF STUDY

Cost effectiveness study.

LEVEL OF EVIDENCE

Level III.

Lack of discreet colocalization of epithelial apoptosis to the atretic precursor in the colon of the Fibroblast growth factor receptor 2IIIb mouse and staining consistent with cellular movement suggest a revised model of atresia formation

BACKGROUND

Colonic atresias in the Fibroblast growth factor receptor 2IIIb (Fgfr2IIIb) mouse model have been attributed to increased epithelial apoptosis and decreased epithelial proliferation at embryonic day (E) 10.5. We therefore hypothesized that these processes would colocalize to the distal colon where atresias occur (atretic precursor) and would be excluded or minimized from the proximal colon and small intestine.

RESULTS

We observed a global increase in intestinal epithelial apoptosis in Fgfr2IIIb ^-/- intestines from E9.5 to E10.5 that did not colocalize to the atretic precursor. Additionally, epithelial proliferations rates in Fgfr2IIIb ^-/- intestines were statistically indistinguishable to that of controls at E10.5 and E11.5. At E11.5 distal colonic epithelial cells in mutants failed to assume the expected pseudostratified columnar architecture and the continuity of the adjacent basal lamina was disrupted. Individual E-cadherin-positive cells were observed in the colonic mesenchyme.

CONCLUSIONS

Our observations suggest that alterations in proliferation and apoptosis alone are insufficient to account for intestinal atresias and that these defects may arise from both a failure of distal colonic epithelial cells to develop normally and local disruptions in basal lamina architecture.

RW-2018-Research Workshop: The Effect of Nutrition on Epigenetic Status, Growth, and Health

The goal of the 2018 American Society for Parenteral and Enteral Nutrition (ASPEN) Research Workshop was to explore the influence of nutrition and dietary exposure to xenobiotics on the epigenome during critical periods in development and how these exposures influence both disease incidence and severity transgenerationally. A growing compendium of research indicates that the incidence and severity of common and costly human diseases may be influenced by dietary exposures and deficiencies that modify the epigenome. The greatest periods of vulnerability to these exposures are the periconception period and early childhood. Xenobiotics in the food chain, protein malnutrition, and methyl donor deficiencies could have a profound bearing on the risk of developing heart disease, diabetes, obesity, hypertension, and mental illness over multiple generations. The financial impact and the life burden of these diseases are enormous. These and other aspects of nutrition, epigenetics, and health are explored in this research workshop.

Management of asymptomatic pediatric umbilical hernias: a systematic review

INTRODUCTION

Uncomplicated pediatric umbilical hernias are common and most close spontaneously. No formal practice guidelines exist regarding the optimal timing and indications for repair. The objective of this review is to examine the existing literature on the natural history of pediatric umbilical hernias, known complications of repair and non-operative approaches, and management recommendations.

STUDY DESIGN

A systematic literature search was performed to identify publications relating to pediatric umbilical hernias. Inclusion criteria comprised studies addressing recommendations for optimal timing of repair, evidence examining complications from hernias not operatively repaired, and research exploring the likelihood of pediatric umbilical hernias to close spontaneously. In addition, the websites of all pediatric hospitals in the United States were examined for recommendations on operative timing.

RESULTS

A total of 787 manuscripts were reviewed, and 28 met criteria for inclusion in the analysis. Studies examined the likelihood of spontaneous closure based on child's age and size of hernia defect, complications of unrepaired umbilical hernias including incarceration, strangulation and evisceration based on child's age and size of defect, incidence of postoperative complications and current recommendations for timing of repair. In addition, 63 (27.5%) of the United States pediatric hospital websites published a wide range of management recommendations.

CONCLUSION

Despite the high prevalence of pediatric umbilical hernias, there is a paucity of high quality data to guide management. The literature does suggest that expectant management of asymptomatic hernias until age 4-5years, regardless of size of hernia defect, is both safe and the standard practice of many pediatric hospitals.

TYPE OF STUDY

Review Article.

LEVEL OF EVIDENCE

Level IV.

Long-Term Outcomes of Patients with Tracheoesophageal Fistula/Esophageal Atresia: Survey Results from Tracheoesophageal Fistula/Esophageal Atresia Online Communities

Introduction Outcome studies of tracheoesophageal fistula (TEF) and/or esophageal atresia (EA) are limited to retrospective chart reviews. This study surveyed TEF/EA patients/parents engaged in social media communities to determine long-term outcomes. Materials and Methods A 50-point survey was designed to study presentation, interventions, and ongoing symptoms after repair in patients with TEF/EA. It was validated using a test population and made available on TEF/EA online communities. Results In this study, 445 subjects completed the survey during a 2-month period. Mean age of patients when surveyed was 8.7 years (0-61 years) and 56% were male. Eighty-nine percent of surveys were completed by the parent of the patient. Sixty-two percent of patients underwent repair in the first 7 days of life. Standard open repair was most common (56%), followed by primary esophageal replacement (13%) and thoracoscopic repair (13%). Out of 405, 106 (26%) patients had postoperative leak. Postoperative leak was least likely in primary esophageal replacement (18%) and standard open repair (19%). Leak occurred in 32% of patients who had thoracoscopic repair; 31% (128/413) reported long-gap atresia, which was significantly associated with increased risk of postoperative leak (54/128, 42%) when compared with standard short-gap atresia (odds ratio, 3.5; p = 0.001). Out of 409, 221 (54%) patients reported dysphagia after repair, with only 77/221 (34.8%) reporting resolution by age 5. Out of 381, 290 (76%) patients reported symptoms of gastroesophageal reflux disease (GERD). There was no difference in dysphagia rates or GERD symptoms based on type of initial repair. Antireflux surgery was required in 63/290, 22% of patients with GERD (15% of all patients) and 27% of these patients who had surgery required more than one procedure antireflux procedure. The most common was Nissen fundoplication (73%), followed by partial wrap (14%). Reflux recurred in 32% of patients after antireflux surgery. Conclusion TEF/EA patients have long-term dysphagia and GERD that may be under reported. Retrospective studies of outcomes after TEF/EA repair may underestimate long-term esophageal dysmotility, dysphagia, GERD, and strictures that occur regardless of the type of repair and adversely affect quality of life. Fifteen percent of all TEF/EA patients surveyed required an antireflux procedure during childhood, and more than one-quarter of those required repeat surgery. These data demonstrate the need for long-term follow-up as pediatric patients transition to adult care.

A Single Institution Review of Initial Application of a 5-mm Stapler

BACKGROUND

Operating in small spaces presents physical constraints that can be even more challenging in minimally invasive operations. Recently, a 5-mm stapler was approved for use in general surgery and pediatric surgery. Here, we present our initial experience using the 5-mm stapler in pediatric general surgery.

MATERIALS AND METHODS

A retrospective chart review was conducted to identify cases using the 5-mm stapler at our institution. Demographic data included age (in months) and weight (in kilograms). Operative data included indication for use, number of loads used, complications related to 5-mm stapler use, and interventions to address complications. A second review focused on patients undergoing the same operations, but using a 10-mm stapler.

RESULTS

A total of 60 staple loads were deployed in 32 procedures. There were four adverse outcomes, all recognized intraoperatively. One bleed resulted from application on irradiated tissue and another bleed from application to a small noninflamed mesoappendix. A bronchial staple line leak resulted from improper stapler loading, and a bowel anastomosis leak was oversewn with a single stitch. When compared with 32 matched cases using a 10-mm stapler, there was no difference in age (5-mm = 39.11 months, 10-mm = 50.21 months, P = .49) or weight (5-mm = 16.34 kg, 10-mm = 19.93 kg, P = .51). A total of 60 staple applications were used, with one bleed noted. There was no significant difference in overall complication rate (5-mm rate = 4/60, 10-mm rate = 1/60; P = .36).

CONCLUSION

Our initial experience suggests that although there were more complications with the 5-mm stapler, there is no statistically significant difference in complication rates when compared with the 10-mm stapler. Furthermore, the 5-mm stapler complications can be corrected with device training and proper patient selection. In appropriately selected pediatric surgery cases with size limitations, the 5-mm stapler can be used to minimize the invasiveness of the operation.

National trends in pediatric blunt spleen and liver injury management and potential benefits of an abbreviated bed rest protocol

PURPOSE

Recent reports suggest that an abbreviated bed rest protocol (ABRP) may safely reduce length of stay (LOS) and resource utilization in pediatric blunt spleen and liver injury (BSLI) patients. This study evaluates national temporal trends in BLSI management and estimates national reduction in LOS using an ABRP.

METHODS

Pediatric patients (<18 years old) sustaining BLSI were identified in the Kids' Inpatient Database from 2000 to 2009. Yearly rates of injury and operative intervention were examined and stratified by type of injury. APSA guidelines and the reported ABRP were applied based on abbreviated injury score (AIS) and compared with actual LOS.

RESULTS

22,153 patients were identified. Over the study period, operative rates for spleen and liver injuries and overall mortality significantly declined: LOS=3.1 days (±1.6) and 2.7 days (±1.9) for spleen and liver, respectively. If APSA guidelines were followed, the rates were LOS=3.7 days (±1.1) and 3.4 days (±0.7), respectively. Application of the ABRP would result in LOS=1.3 days (±0.5) for all BSLI patients. An ABRP could potentially save 1.7 hospital days/patient or 36,964 patient hospital days nationally.

CONCLUSION

Our study confirms a significant national decrease in operative intervention and overall mortality in patients with BSLI. Additionally, it appears that a shorter observation period than the APSA guidelines is being utilized. The implementation of ABRP holds potential in further reducing LOS and resource utilization.

Utility and limits of Hprt-Cre technology in generating mutant mouse embryos

BACKGROUND

Hprt-Cre doubles the prevalence of homozygous null embryos per litter versus heterozygous breedings without decreasing litter size. Resulting mutant embryos are genotypically and phenotypically equivalent between strategies. We set out to confirm the effectiveness of this approach with other alleles and hypothesized that it would increase efficiency in generating compound mutants.

MATERIALS AND METHODS

Null mutants for Cyp26b1, Pitx2, and Shh were generated with Hprt-Cre from conditional alleles as were double and triple allelic combinations of Fgfr2IIIb, Raldh2, and Cyp26b1. Embryos were genotyped and phenotyped by whole mount photography, histology, and immunohistochemistry.

RESULTS

Fifty percent of Hprt-Cre litters were homozygous null for Cyp26b1 (15/29) and Pitx2 (75/143), with phenotypic and genotypic equivalence to mutants from standard heterozygous breedings. In multi-allele breedings, mutant embryos constituted half of litters without significant embryo loss. In contrast, Shh breedings yielded a smaller ratio of embryos carrying two recombined alleles (6 of 16), with a significant litter size reduction because of early embryonic lethality (16 live embryos from 38 deciduae).

CONCLUSIONS

Hprt-Cre can be used to efficiently generate large numbers of mutant embryos with a number of alleles. Compound mutant generation was equally efficient. However, efficiency is reduced for genes whose protein product potentially interacts with the Hprt pathway (e.g., Shh).

Haploinsufficiency of retinaldehyde dehydrogenase 2 decreases the severity and incidence of duodenal atresia in the fibroblast growth factor receptor 2IIIb-/- mouse model

BACKGROUND

Homozygous null mutation of the fibroblast growth factor receptor 2IIIb (Fgfr2IIIb) gene in mice results in 42% of embryos developing duodenal atresias. Retinaldehyde dehydrogenase 2 (Raldh2, a gene critical for the generation of retinoic acid) is expressed in the mouse duodenum during the temporal window when duodenal atresias form. Raldh2 is critical for the normal development of the pancreatoduodenal region; therefore, we were interested in the effect of a Raldh2 mutation on duodenal atresia formation. To test this, we rendered Fgfr2IIIb(-/-) embryos haploinsufficient for the Raldh2 and examined these embryos for the incidence and severity of duodenal atresia.

METHODS

Control embryos, Fgfr2IIIb(-/-) mutants, and Fgfr2IIIb(-/-); Raldh2(+/-) mutants were harvested at embryonic day 18.5, genotyped, and fixed overnight. Intestinal tracts were isolated. The type and severity of duodenal atresia was documented.

RESULTS

A total of 97 Fgfr2IIIb(-/-) embryos were studied; 44 had duodenal atresias, and 41 of these presented as type III. In the 70 Fgfr2IIIb(-/-); Raldh2(+/-) embryos studied, a lesser incidence of duodenal atresia was seen (15 of 70; P = .0017; Fisher exact test). Atresia severity was also decreased; there were 12 embryos with type I atresias, 3 with type II atresias, and 0 with type III atresias (P < 2.81E-013; Fisher exact test).

CONCLUSION

Haploinsufficiency of Raldh2 decreases the incidence and severity of duodenal atresia in the Fgfr2IIIb(-/-) model. The ability to alter defect severity through manipulation of a single gene in a specific genetic background has potentially important implications for understanding the mechanisms by which intestinal atresias arise.

Muscle patterning in mouse and human abdominal wall development and omphalocele specimens of humans

Human omphalocele is a congenital defect of the abdominal wall in which the secondary abdominal wall structures (muscle and connective tissue) in an area centered around the umbilicus are replaced by a translucent membranous layer of tissue. Histological examination of omphalocele development and moreover the staging of normal human abdominal wall development has never been described. We hypothesized that omphalocele is the result of an arrest in the secondary abdominal wall development and predicted that we would observe delays in myoblast maturation and an arrest in secondary abdominal wall development. To look for evidence in support of our hypothesis, we performed a histological analysis of normal human abdominal wall development and compared this to mouse. We also conducted the first histological analysis of two human specimens with omphalocele. In these two omphalocele specimens, secondary abdominal wall development appears to have undergone an arrest around Carnegie Stage 19. In both specimens disruptions in the unidirectional orientation of myofibers were observed in the external and internal obliques, and rectus abdominis but not in the transversus abdominis. These latter findings support a model of normal abdominal wall development in which positional information instructs the orientation of myoblasts as they organize into individual muscle groups.

Formation of intestinal atresias in the Fgfr2IIIb-/- mice is not associated with defects in notochord development or alterations in Shh expression

PURPOSE

The etiology of intestinal atresia remains elusive but has been ascribed to a number of possible events including in utero vascular accidents, failure of recanalization of the intestinal lumen, and mechanical compression. Another such event that has been postulated to be a cause in atresia formation is disruption in notochord development. This hypothesis arose from clinical observations of notochord abnormalities in patients with intestinal atresias as well as abnormal notochord development observed in a pharmacologic animal model of intestinal atresia. Atresias in this model result from in utero exposure to Adriamycin, wherein notochord defects were noted in up to 80% of embryos that manifested intestinal atresias. Embryos with notochord abnormalities were observed to have ectopic expression of Sonic Hedgehog (Shh), which in turn was postulated to be causative in atresia formation. We were interested in determining whether disruptions in notochord development or Shh expression occurred in an established genetic model of intestinal atresia and used the fibroblast growth factor receptor 2IIIb homozygous mutant (Fgfr2IIIb-/-) mouse model. These embryos develop colonic atresias (100% penetrance) and duodenal atresias (42% penetrance).

METHODS

Wild-type and Fgfr2IIIb-/- mouse embryos were harvested at embryonic day (E) 10.5, E11.5, E12.5, and E13.5. Whole-mount in situ hybridization was performed on E10.5 embryos for Shh. Embryos at each time point were harvested and sectioned for hematoxylin-eosin staining. Sections were photographed specifically for the notochord and resulting images reconstructed in 3-D using Amira software. Colons were isolated from wild-type and Fgfr2IIIb-/- embryos at E10.5, then cultured for 48 hours in Matrigel with FGF10 in the presence or absence of exogenous Shh protein. Explants were harvested, fixed in formalin, and photographed.

RESULTS

Fgfr2IIIb-/- mouse embryos exhibit no disruptions in Shh expression at E10.5, when the first events in atresia formation are known to occur. Three-dimensional reconstructions failed to demonstrate any anatomical disruptions in the notochord by discontinuity or excessive branching. Culture of wild-type intestines in the presence of Shh failed to induce atresia formation in either the duodenum or colon. Cultured Fgfr2IIIb-/- intestines developed atresias of the colon in either the presence or absence of Shh protein.

CONCLUSIONS

Although disruptions in notochord development can be associated with intestinal atresia formation, in the Fgfr2IIIb-/- genetic animal model neither disruptions in notochord development nor the presence of exogenous Shh protein are causative in the formation of these defects.

A more efficient method to generate null mutants using Hprt-Cre with floxed alleles

PURPOSE

The generation of nonviable homozygous null mouse embryos from heterozygote null/+ breedings can be highly resource consuming, with only 25% of the embryos in the litter being null mutants. We hypothesized that (1) we could double the number of homozygous null mouse embryos in a litter without reducing litter size using Hypoxanthine-guanine phosphoribosyltransferase-Cre (Hprt)-Cre (which is active in the female germ line at the time of fertilization), and (2) these homozygous null mutants would be identical to mutants generated through traditional null/+ breedings.

METHODS

To test this hypothesis, we used a conditional allele Fgfr2IIIb(flox). This allele when recombined is identical to the Fgfr2IIIb(null) allele. An F1 generation of Fgfr2IIIb(rec/+); Hprt(Cre/+) females was created by mating Fgfr2IIIb(+/+); Hprt(cre)(/cre) females to a Fgfr2IIIb(flox/flox) male. The F1 females were then mated to a Fgfr2IIIb(flox/flox) male. F2 embryos were genotyped, and the morphology and histology of the lungs, intestine, limbs, and brain were analyzed.

RESULTS

The Hprt-Cre mating strategy results in 51% of pups being genotypic homozygous null embryos (85/166) vs 23% for the standard null/+ approach (38/167). These embryos did not express the Fgfr2IIIb transcript and were phenotypically identical to null embryos generated through standard null/+ breedings.

CONCLUSIONS

The Hprt-Cre mating strategy increases the number of homozygous mutant embryos in a litter without decreasing litter size. Embryos generated through this approach are phenotypically identical to those from standard heterozygous breedings. We recommend this approach to investigators using a model system that relies on the generation of homozygous null embryos.

Pitx2 is a critical early regulatory gene in normal cecal development

BACKGROUND

The murine cecum is a critical digestive structure. Morphogenesis of the cecum involves several key genes, including Homeobox (Hox) d12. Ectopic expression of Hoxd12 has been shown to result in cecal agenesis and a down-regulation of both Fibroblast growth factor 10 (Fgf10) and the Pituitary homeobox 2 gene (Pitx2). Homozygous null mutation of Fgf10 or its cognate receptor Fgfr2IIIb results in severe cecal defects where there is the initiation of mesodermal budding, but a failure of the endoderm to grow and extend into this structure. We examined the expression of Pitx2 in the cecum and hypothesized that homozygous null mutation of Pitx2 would result in cecal agenesis.

METHODS

IACUC approval was obtained for these studies. Whole mount in situ hybridizations for Pitx2 were performed on wild-type embryos between embryonic d (E)11.0 and E12.5. Pitx2 -/- and Fgfr2IIIb -/- embryos were generated from n/+ heterozygote breedings and harvested at E10.5, E11.5, and E13.5. Genotypes were confirmed by PCR. Morphology of Pitx2 -/- cecae were compared with those of wild-type littermates and Fgfr2IIIb -/- embryos at identical stages. Embryos were fixed overnight and photographed the following day.

RESULTS

Pitx2 is expressed in the cecal mesoderm and endoderm as early as E11.0. Expression becomes increasingly more robust by E12.5. Homozygous null mutation of Pitx2 results in agenesis of the cecum. In contrast to Fgfr2IIIb -/- embryos, which demonstrate a persistent mesodermal bud as late as E18.5, no mesodermal bud is present in Pitx2 -/- embryos.

CONCLUSIONS

Our findings demonstrate that Pitx2 is a critical regulatory gene in cecal morphogenesis and suggest that Pitx2 is required for initiation of mesodermal budding and likely resides upstream of Fgf10-Fgfr2IIIb signaling in the normal development of this structure.

Enlarging unilateral breast mass in an adolescent male: an unusual presentation of intraductal papilloma

Breast masses presenting in adolescent boys are rare and are almost uniformly owing to gynecomastia. Although surgical referral for breast masses in adolescent boys is common, intervention is typically for cosmesis. We report the case of a 14-year-old boy who presented with an enlarging unilateral breast mass, which was found to be owing to an intraductal papilloma at the time of surgical excision.

Humans, mice, and mechanisms of intestinal atresias: a window into understanding early intestinal development

INTRODUCTION

Intestinal atresias have long been hypothesized to result from either failure of recanalization of the intestinal lumen or in utero vascular accidents. Recent work in animal models is now calling for a reassessment of these widely held paradigms.

PURPOSE

In this review, we will examine the data that led to the original hypotheses and then evaluate more recent work challenging these hypotheses. Furthermore, we will discuss how defining the mechanism of atresia formation in animal models may provide insight into early intestinal development and the mechanism of lengthwise intestinal growth.

CONCLUSION

Such insight will be critical in developing regenerative therapies for patients with intestinal failure.

Retinaldehyde dehydrogenase 2 is down-regulated during duodenal atresia formation in Fgfr2IIIb-/- mice

BACKGROUND

Homozygous null mutation of fibroblast growth factor receptor 2 (Fgfr2IIIb) or its ligand fibroblast growth factor 10 (Fgf10) results in duodenal atresia in mice. Mutations of either of these genes in humans cause Matthew-Wood syndrome and associated duodenal stenosis. Recently, mutations in the retinol-binding protein receptor gene STRA6 were reported to be implicated in this syndrome as well. This suggests that the retinoic acid (RA) signaling pathway interacts with the Fgf10-Fgfr2IIIb signaling pathway during duodenal development. Accordingly, we hypothesized that Fgfr2IIIb-/- mouse embryos would exhibit disruptions in expression of Raldh2, the gene for the enzyme that regulates the final step in the conversion of vitamin A to the active form RA, during duodenal atresia formation.

MATERIALS AND METHODS

Fgfr2III -/- mice were generated from heterozygous breedings. Embryos were harvested between embryonic day (E) 11.0 to E 13.5 and genotyped by polymerase chain reaction (PCR). Duodenums were dissected out, fixed and photographed. Whole mount and section in situs were performed for Raldh2.

RESULTS

Fgfr2IIIb-/- embryos demonstrate subtle changes in the duodenal morphology by E11.5 with complete involution of the atretic precursor by E 13.5. Raldh2 appears to be down-regulated as early as E 11.5 in the atretic precursor a full 2 days before this segment disappears.

CONCLUSIONS

In Fgfr2IIIb-/- mouse embryos, a reduction of Raldh2 expression is observed within the region that is forming the atresia. This is the first demonstration of such an event in this model. As in humans, these results implicate disruptions between Fgfr2IIIb receptor function and RA signaling in the formation of this defect and indicate that Fgfr2IIIb-/- mouse embryos are a valid model for the study of the atretic spectrum of defects in human duodenal development.

Conditional mutation of fibroblast growth factor receptors 1 and 2 results in an omphalocele in mice associated with disruptions in ventral body wall muscle formation

BACKGROUND/PURPOSE

We observed that fibroblast growth factor receptors 1 and 2 (Fgfr1, Fgfr2) are expressed during abdominal wall development in mice and hypothesized that conditional mutation of these genes would result in abdominal wall defects.

METHODS

Section in situ hybridizations were performed for Fgfr1 and Fgfr2 on wild-type embryos at embryonic day (E) 11.5 and E13.5. Conditional mutation of Fgfr1and Fgfr2 was achieved with a tamoxifen inducible Cre at E8.5. Litters were harvested at E17.5, whole mount photographs were taken, and paraffin sections were generated and stained with hematoxylin and eosin.

RESULTS

Fgfr1 was expressed in ectoderm, lateral plate mesoderm, and myoblasts, whereas Fgfr2 was expressed almost exclusively in the early dermis and ectoderm of the abdominal wall. Conditional mutation of both Fgfr2 alleles and one Fgfr1 allele resulted in omphalocele in 38.7% of mutants. Histologic examination in mutants demonstrated disruptions in dermal and muscle development.

CONCLUSIONS

Mutant embryos with omphalocele arising from mutation in Fgfr1 and Fgfr2 exhibit disruptions in the development of the secondary abdominal wall structures. These findings are consistent with a model of ventral abdominal wall development in which organization of the muscles and connective tissue (secondary abdominal wall structures) is influenced by positional information emanating from the primary abdominal wall.

What is the optimal treatment for children with primary hyperparathyroidism?

PURPOSE

Little information exists regarding the optimal surgical treatment of pediatric primary hyperparathyroidism. We hypothesized that primary hyperparathyroidism in children, in the absence of a family history, is caused by single-gland disease and is amenable to minimally invasive parathyroidectomy (MIP).

METHODS

We reviewed the records of individuals younger than 25 years who underwent parathyroidectomy in a prospectively collected database at a single tertiary hospital from 2003 to 2009.

RESULTS

Twenty-five patients were identified, with a mean (SD) age of 19 (3.7) years. Sixty percent had single-gland disease (n = 15). Familial disease was present in 6 patients. All of the children younger than 18 years without a family history of disease (9/9) were found to have a single-gland disease (P < .001). Seventy-eight percent of patients without a family history were successfully treated without a bilateral exploration. Average length of stay was less than 1 day with no complications or recurrences.

CONCLUSIONS

Primary hyperparathyroidism in patients younger than 18 years without a family history was uniformly caused by single-gland disease. Minimally invasive parathyroidectomy was successful in these patients and avoided the morbidity of bilateral exploration. We recommend MIP be used in pediatric patients at large referral centers with prior successful institutional experience with the technique.

Portal vein thrombus after pediatric proctocolectomy with ileoanal anastomosis

In adults, mesenteric venous thrombosis with extension into the portal system is a known complication of total proctocolectomy with pouch ileoanal anastomosis. Although frequently reported in adults, this complication is rare in pediatric patients undergoing this operation. We report 2 cases of adolescent patients with ulcerative colitis who experienced portal vein thrombosis after this procedure. Both were treated with systemic anticoagulation therapy with complete resolution of their clots. We recommend that mesenteric/portal venous thrombosis be considered in the differential diagnosis in any child presenting with fever, abdominal pain, and leukocytosis after restorative proctocolectomy with ileal pouch anastomosis and that imaging obtained to evaluate abdominal complaints in this population be directed toward ruling out this complication.

Closed gastroschisis: total parenteral nutrition-free survival with aggressive attempts at bowel preservation and intestinal adaptation

BACKGROUND

In infants with gastroschisis antenatal closure of the umbilical defect results in a proximal atresia with ischemia and/or volvulus of the extracorporeal midgut. It has been described as "closed gastroschisis" or "vanishing midgut."

METHODS

A 10-year review of 219 gastroschisis patients identified 10 infants with this rare complication.

RESULTS

In these 10 infants, the extracorporeal midgut was invariably matted and fibrosed. In 3 cases, the midgut had completely "vanished." In the remaining 7 cases, the remnant midgut was surgically reduced into the abdominal cavity with care not to compromise the diminutive vascular pedicle. Abdominal exploration was performed several weeks later to reestablish bowel continuity; 4 required an ostomy and 2 underwent a serial transverse enteroplasty. Mean residual length of salvaged small bowel was 79 cm with retention of the distal half of the colon. Eight infants survived the initial hospitalization, with a mean length of stay of 121 days and mean hospital charge of $287,094. Six of the 7 long-term survivors have been completely weaned off total parenteral nutrition.

CONCLUSION

A nihilistic attitude toward infants with closed gastroschisis may not be uniformly supported because in the majority of these infants' long-term independence from total parenteral nutrition was achieved.

Acute appendicitis in a patient with hemolytic uremic syndrome: an unusual clinical scenario

Gastroenteritis due to Escherichia coli O157:H7 occurs in young children and is associated with consumption of under cooked beef. Approximately 5-10% of patients will develop hemolytic uremic syndrome (HUS): renal failure, microangiopathic hemolytic anemia, and thrombocytopenia. A 6-year-old boy was admitted with abdominal pain, guaiac positive stool, decreased urine output and elevated creatinine levels. Hemodialysis was initiated upon rapid progression to anuria. On hospital day # 5 he developed acute abdominal pain, which was different from his initial assessment. Exam revealed focal tenderness in the right lower quadrant with localized guarding and rebound. Ultrasound demonstrated a dilated, fluid filled tubular structure in the RLQ concerning for appendicitis. Based on these findings the patient was taken to the operating room for a laparoscopic appendectomy. The patient had undergone dialysis the previous day and was preoperatively treated with DDAVP to minimize the risk of bleeding. The procedure occurred without complication and final pathology confirmed acute appendicitis. This case highlights the unique clinical scenario in which patients with HUS require operative intervention. Surgical procedures can be performed on these patients, however, all precautions should be taken to minimize the risk of bleeding, including the use of preoperative DDAVP.

The split abdominal wall muscle flap repair for large congenital diaphragmatic hernias on extracorporeal membrane oxygenation

BACKGROUND

Numerous techniques exist for repairing large congenital diaphragmatic hernias (CDHs) including prosthetic patches, tissue-engineered grafts, and various muscle flaps. A split abdominal wall muscle flap is a simple, durable way to repair a large diaphragmatic hernia. This technique has not gained widespread use, and some have suggested that it would be inappropriate in the setting of extracorporeal membrane oxygenation (ECMO) because of bleeding risk. We present our series of diaphragmatic hernias with a focus on those repaired with the split abdominal wall technique while on ECMO.

METHODS

A retrospective, single-institution chart review was performed on all patients who underwent surgical repair for CDH over 6 years beginning in August 2000.

RESULTS

Seventy-five patients underwent repair. Sixteen were performed with patients on ECMO. Of these, 4 were closed primarily, 7 used a prosthetic patch, and 5 used a split abdominal wall muscle flap. Two patients in the prosthetic group developed a recurrent hernia, and 2 required reoperation for bleeding while on ECMO. No reoperations for bleeding were required in the abdominal muscle flap group.

CONCLUSIONS

The split abdominal wall muscle flap can be safely performed on anticoagulated patients. We believe it is a practical option for repairing large CDHs.

Temporary abdominal vacuum-packing closure in the neonatal intensive care unit

BACKGROUND

Temporary abdominal vacuum-packing (vac-pac) closure is well known in adult literature, yet has not been reported in infants.

METHODS

A review of children in the neonatal intensive care unit who underwent vac-pac closure from 2000 to 2006 was performed.

RESULTS

During this time, 7 infants underwent vac-pac closure after abdominal surgery. Median age was 39 days, with a median weight of 3.2 kg. Reasons for vac-pac included abdominal compartment syndrome (3), ongoing intraabdominal sepsis (1), anticipated second-look procedures (2), and abdominal observation after repair of congenital diaphragmatic hernia on extracorporeal membrane oxygenation (1). PaCO2 revealed a drop from a median preoperative level of 50.3 to 44.0 mm Hg postoperatively. Median preoperative urine output was 3.9 and 3.1 mL/(kg h) postoperatively. One patient died with an open abdomen from overwhelming Escherichia coli sepsis, and all surviving patients (85.7%) proceeded to definitive abdominal closure with the median time of vac-pac use being 4 days.

CONCLUSION

Vac-pac closure in infants is a safe and effective method of temporary abdominal closure. The detrimental effects of intraabdominal hypertension as well as risk of hemorrhage after repair of congenital diaphragmatic hernia while on extracorporeal membrane oxygenation also make this an important technique for abdominal observation.

Ad Libitum Feeds After Laparoscopic Pyloromyotomy: A Retrospective Comparison with a Standardized Feeding Regimen in 227 Infants

PURPOSE

The best feeding regimen after pyloromyotomy for hypertrophic pyloric stenosis continues to be a topic of some debate. Postoperative emesis and length of hospital stay are principal concerns. We compared the outcome of infants after laparoscopic pyloromyotomy who were fed using a standardized feeding regimen or ad libitum.

MATERIALS AND METHODS

We reviewed the records of 227 infants who underwent laparoscopic pyloromyotomy within a 5-year period. We compared two sets of patients: those fed using a standardized feeding regimen and those fed ad libitum. The choice of feeding regimen was based solely on the attending surgeon's preference. Each group was examined for frequency of postoperative emesis, time to full feeds, and length of hospital stay.

RESULTS

Of the 227 patients in the study, 170 (74.9%) were fed using the standardized feeding regimen and 57 (25.1%) were fed ad libitum. The two groups were comparable with respect to age and sex distribution. Although children fed ad libitum had a significantly shorter time to full feeds that those fed a standardized feeding regimen (19.0 vs. 23.1 hours; P < 0.01), there was no significant difference in the frequency of postoperative emesis (1.8 vs. 1.9 times per patient; P = 0.68) or total length of hospital stay (49.0 vs. 50.3 hours; P = 0.73) when the ad libitum and standardized feed groups were compared. There were no complications in either group.

CONCLUSION

A standardized feeding regimen offers no advantage over ad libitum feeds for infants who have undergone laparoscopic pyloromyotomy. Infants fed ad libitum are able to tolerate full feeds sooner and the frequency of postoperative emesis is not increased. Ad libitum feeding has become the standard postoperative feeding regimen for infants who have undergone pyloromyotomy at our hospital.

Streptococcal pancreatitis and toxic shock syndrome in a 2-month-old infant

The rare clinical scenario of an infant with group A streptococcal pancreatitis associated with toxic shock syndrome is reported. The presentation, evaluation, and management of this unusual clinical entity are discussed.

Gallstone ileus 20 years after a Kasai procedure using a stapled antireflux valve

We present a case of intestinal obstruction owing to a gallstone ileus in a patient 20 years after a Kasai procedure for biliary atresia in which a stapled antireflux valve was constructed to treat recurrent cholangitis. The etiology of this rare presentation is discussed.

Comparison of outcomes after laparoscopic and open pyloromyotomy at a high-volume pediatric teaching hospital

BACKGROUND/PURPOSE

Laparoscopic pyloromyotomy (LP) is used widely for treatment of hypertrophic pyloric stenosis. We examined the results of pyloromyotomy at a high-volume pediatric teaching hospital to compare outcomes of laparoscopic and open pyloromyotomy (OP).

METHODS

We reviewed the records of all patients who underwent pyloromyotomy at our institution over a 5-year period. Data were collected regarding operative time, time to full feeds, length of hospital stay, complications, and frequency of postoperative emesis.

RESULTS

There were 335 pyloromyotomies: 212 laparoscopic and 123 open. Five patients in the laparoscopic group required conversion to an open procedure. There were no significant differences in operative time (LP, 30.5 minutes; OP, 32.0 minutes), time to full feeds (LP, 22.4 hours; OP, 23.5 hours), frequency of postoperative emesis (LP, 1.8; OP, 2.2), or length of hospital stay (LP, 49.3 hours; OP, 50.5 hours). There were 5 mucosal perforations in the laparoscopic group and 2 in the open group (LP, 2.3%; OP, 1.6%). There were 3 incomplete pyloromyotomies in the laparoscopic group and none in the open group. Four perforations and all incomplete myotomies occurred in the first 2 years after the laparoscopic technique was introduced at our institution. The overall complication rate was similar (LP, 3.7%; OP, 3.2%).

CONCLUSIONS

Laparoscopic pyloromyotomy is a safe and effective alternative to OP. There appears to be an institutional learning curve when the laparoscopic technique is introduced as reflected by slightly higher rates of mucosal injury and incomplete pyloromyotomy.

Ileo-anal S-Pouch reconstruction in patients with total colonic aganglionosis after failed pull-through procedure

Total colonic aganglionosis (TCA) occurs in 3% to 12% of Hirschsprung's disease patients. Although numerous surgical techniques have been utilized for the treatment of these patients, little information is available regarding optimal surgical management of their frequent complications or failured procedures. The ileoanal S pouch (IASP) technique has been utilized in the treatment of children with familial adenomatous polyposis and ulcerative colitis. The authors present the results of salvage IASP in 3 TCA patients who had poor results after total colectomy and Soave pull-through.

Perforation of the appendix from intestinal mucormycosis in a neonate

A premature neonate had pneumoperitoneum 5 days after discontinuation of extracorporeal membrane oxygenation therapy. A perforated appendix was found at exploratory laparotomy. Pathologic examination of the appendix found mucormycosis.

Long-term follow-up in a patient after pneumonectomy and SILASTIC prosthetic placement for unilateral pulmonary artery agenesis

Unilateral pulmonary artery agenesis is an exceedingly rare condition. The authors report the case of a 9-year-old girl with unilateral pulmonary artery agenesis who presented with exertional hemoptysis. The patient underwent a right pneumonectomy with placement of an expandable. SILASTIC(R) (Dow Corning, Midland, MI) prosthesis in the right thorax. A 13-year follow-up is reported, and management of this condition is discussed.

Meconium staining of amniotic fluid correlates with intestinal peel formation in gastroschisis

Several studies in animal models demonstrate that peel formation in gastroschisis is due to the accumulation and activation of intestinal waste products (IWP) in the amniotic fluid. We reviewed our recent experience with gastroschisis and asked the following questions: First, does staining of the bowel and amniotic fluid with IWP correlate with intestinal peel formation? Second, what prenatal ultrasound findings indicate that peel formation is occurring in utero? Over two years, 16 neonates were treated for gastroschisis; twelve had been diagnosed by prenatal ultrasound and followed closely. Patients were grouped based on the presence of IWP in the amniotic fluid at the time of delivery (staining or no staining), and outcomes were reviewed. All neonates in the staining group (n=7) had a fibrinous peel present at the time of birth whereas a peel was absent in all neonates in the no-staining group (n=9). Matting of the bowel was seen by prenatal ultrasound in four patients in the staining group (0/8 in the no-staining group) and correlated with peel formation (Fisher's exact test p =0.007). Primary closure was done in 14 of the infants, and two required silo closure. In neonates with gastroschisis, staining of the amniotic fluid and bowel serosa with IWP correlated with intestinal peel formation. The ultrasound findings of matting correlated with both peel formation and staining with IWP. These results suggest that spillage of IWP into the amniotic fluid is one of the factors in peel formation in gastroschisis. Identification of matting of the bowel by prenatal ultrasound indicates formation of a peel.

Radioguided parathyroidectomy in patients with secondary and tertiary hyperparathyroidism

BACKGROUND

To date there have been no reports on the feasibility of radioguided parathyroidectomy (RGP) in patients with secondary and tertiary hyperparathyroidism.

METHODS

Twenty-three consecutive patients with secondary (n=5) or tertiary hyperparathyroidism (n=18) underwent RGP. Patients were injected with 10 mCi of technetium 99-sestamibi before surgery. All parathyroid glands were localized during operation with a neoprobe.

RESULTS

The mean patient age was 50+/-3 years. The mean preoperative calcium and intact parathyroid hormone levels were 11.0+/-0.3 mg/dL and 400+/-107 pg/mL, respectively. Eighteen patients had 3- or 4-gland hyperplasia, 2 had double adenomas, 2 had forearm graft hyperplasia, 1 had 6-gland disease, and 3 had ectopic glands. All hyperplastic glands had ex vivo counts >20% of background (mean, 63%+/-6%), making frozen section unnecessary. When compared with 66 historical control subjects who underwent surgery without radioguidance for tertiary hyperparathyroidism, patients undergoing RGP had decreased operative times (96+/-8 minutes vs 151+/-15 minutes; P<.001) and lengths of stay (1.3+/-0.1 days vs 3.7+/-0.3 days; P<.001).

CONCLUSIONS

RGP in patients with secondary and tertiary hyperparathyroidism is feasible, may reduce operative time, and permits omission of frozen section. Thus RGP appears to be a useful adjunct in the treatment of secondary and tertiary hyperparathyroidism.

Long-term follow-up of patients with tertiary hyperparathyroidism treated by resection of a single or double adenoma

OBJECTIVE

To determine whether patients with tertiary hyperparathyroidism due to single- or two-gland disease undergoing limited resection have similar long-term outcomes compared with patients with hyperplasia undergoing subtotal or total parathyroidectomy.

SUMMARY BACKGROUND DATA

Tertiary hyperparathyroidism occurs in less than 2% of patients after renal transplantation. Approximately 30% of these cases are caused by one or two hyperfunctioning glands. Nevertheless, the standard operation for this disease has been subtotal or total parathyroidectomy with autotransplantation.

METHODS

Seventy-one patients underwent surgery for tertiary hyperparathyroidism. At the time of surgery, 19 patients who had a single or double adenoma underwent limited resection of the enlarged glands only (adenoma group). The remaining 52 patients with three- or four-gland hyperplasia had subtotal or total parathyroidectomy with implantation (hyper group). Long-term cure rates between the two groups were compared.

RESULTS

In the adenoma group, 7 patients had a single adenoma and 12 underwent resection of a double adenoma. In the hyper group, 49 patients had subtotal and 3 had total parathyroidectomies. After surgery, 70 of 71 patients (99%) were cured of their hypercalcemia. The incidence of postoperative transient hypocalcemia was significantly higher in the hyper group (27% vs. 5%). No patients in either group had permanent hypocalcemia requiring long-term supplementation. With up to 16 years of follow-up, there have been no recurrences in the adenoma group, whereas three patients (6%) in the hyper group have had recurrent or persistent hyperparathyroidism.

CONCLUSIONS

Patients with tertiary hyperparathyroidism who underwent limited resection of a single or double adenoma only had equivalent long-term cure rates compared with patients undergoing more extensive resections. Therefore, the authors recommend in patients with tertiary hyperparathyroidism and enlargement of only one or two parathyroid glands that the resection be limited to these abnormal glands only.

Herpes simplex virus gene expression in neurons: viral DNA synthesis is a critical regulatory event in the branch point between the lytic and latent pathways

Herpes simplex virus establishes a latent infection in peripheral neurons. We examined viral gene expression in rat peripheral neurons in vitro and determined that viral gene expression is attenuated and delayed in these neurons compared with that in Vero cells. In addition, using pharmacologic and genetic blocks to viral DNA synthesis, we found that viral alpha and beta gene expression was upregulated by viral DNA synthesis. Although maximal gene expression in neurons requires viral DNA synthetic activity, activation of viral gene expression was seen even in the presence of herpes simplex virus DNA polymerase inhibitors, but not in the absence of the origin-binding protein. Initiation of viral DNA synthesis is apparently a key regulatory event in the balance between the lytic and latent pathways in peripheral neurons.

Infection of sympathetic and sensory neurones with herpes simplex virus does not elicit a shut-off of cellular protein synthesis: implications for viral latency and herpes vectors

Infection of non-neuronal cell types with herpes simplex virus type 1 (HSV-1) results in the degradation of host mRNA (Kwong & Frenkel 1987) and a shutoff in host protein synthesis (Roizman et al. 1965). This effect is mediated by a virion associated protein that is encoded by the viral vhs gene (Read & Frenkel 1983). This virion host shutoff (VHS) helps regulate viral gene expression and promotes efficient viral replication during the lytic cycle (Kwong & Frenkel 1987). Cultured sympathetic and sensory neurones, in contrast to primary rat fibroblasts, PC-12 cells, and Vero cells, showed no reduction in protein synthesis following infection with HSV-1. The resistance of neurones to VHS may be important in allowing establishment of a latent infection. In addition, this finding has a favourable impact on the idea of using HSV as a vector to deliver foreign genes into neurones.