The Extent of the Transition Zone in Hirschsprung Disease

The Pathologist's Role in the Diagnosis of Hirschsprung's Disease

INTRODUCTION

 The possibilities, recent advances, and pitfalls in the histopathologic workup of specimens submitted for the diagnosis of Hirschsprung's disease (HSCR) are presented.

MATERIALS AND METHODS

 A literature research was performed in the database PubMed including the years 2000 to 2024.

RESULTS

 The pathologist is involved in the diagnosis of HSCR in three scenarios: (1) the primary diagnosis in a child with the typical clinical symptoms, (2) the intra-operative guidance of surgery in a case where the diagnosis is already established, and (3) the confirmation of the diagnosis and the documentation of the extent of the disease in the resected specimen. Identification of ganglion cells in the enteric neural plexuses excludes HSCR, and the histological confirmation of a complete absence of these ganglion cells is the gold standard for its diagnosis. However, difficulties in the detection of ganglion cells with standard stains and/or a limited amount of tissue in the specimen submitted for diagnosis make supportive histologic stains and techniques, e.g., calretinin immunohistochemistry or acetylcholinesterase histochemistry necessary for an unequivocal diagnosis of HSCR.

CONCLUSIONS

 Improving the diagnostic accuracy of this life-threating disease is an interdisciplinary task. A good communication between pathologist and clinician, as well as mutual knowledge of skills and challenges of the other discipline, is necessary for a successful diagnostic teamwork.

Is It Safe to Operate without Frozen Section Biopsies in Short-Segment Hirschsprung's Disease? An Overview of 60 Cases

Background: Advancements in surgical management in a single-stage procedure made intraoperative frozen section biopsies critical for determining of level of resection to avoid the potential risk of leaving a retained aganglionic segment. However, in most low-income countries, due to the lack of this facility, the surgeon's intraoperative judgment is used for the determination of the resection level. Objective: This study aims to evaluate the accuracy of determining the level of bowel resection in short-segment Hirschsprung's disease based on macroscopic changes. Materials and methods: Intraoperative macroscopic evaluations were assessed using postoperative microscopic findings to determine whether the surgeons' intraoperative judgments were accurate in determining the level of bowel resection in 60 cases of operated short-segment Hirschsprung's disease. In addition, Pearson's correlation coefficient was used to determine whether the sensitivity and specificity of both methods were significantly correlated. Results: The microscopic results showed that the level of resection based on the macroscopic evaluation was performed in normally ganglionated segment in cases of short-segment Hirschsprung's disease. Conclusions: Macroscopic intraoperative assessment by an experienced surgeon is highly accurate method of determining the level of bowel resection in short-segment HSCR.

Does Length of Extended Resection Beyond Transition Zone Change Clinical Outcome for Hirschsprung Pull-Through?

INTRODUCTION

A proximal resection margin greater than 5 cm from the intra-operative histologically determined transition zone has been deemed necessary to minimize the risk of transition zone pull-through. This extended resection may require the sacrifice of vascular supply and even further bowel resection. The impact of extended proximal resection margin on post-operative complications and functional outcomes is unclear.

METHODS

A retrospective chart review of patients who underwent primary pull-through for Hirschsprung disease at a single institution between January 2008 and December 2022 was performed. An adequate proximal margin was defined by a circumferential normally ganglionated ring and absence of hypertrophic nerves. The extended margin was defined as the total length of proximal colon with normal ganglion cells and without hypertrophic nerves. Fecal incontinence severity was assessed with the Pediatric Fecal Incontinence Severity Score (PFISS).

RESULTS

Eighty seven patients met criteria for inclusion. Median age at primary pull-through was 17 days (IQR 10-92 days), 55% (n = 48) of patients had an extended proximal margin (EPM) ≤ 5 cm, and 45% (n = 39) had an EPM > 5 cm. An EPM ≤5 cm was not associated with increased rates of Hirschsprung associated enterocolitis (≤5 cm 43%, >5 cm 39%, P = 0.701), diversion post pull-through (≤5 cm 10%, >5 cm 5%, P = 0.367) or reoperation for transition zone pull-through (≤5 cm 3%, >5 cm 0%, P = 0.112). EPM ≤5 cm had more frequent involuntary daytime bowel movements (P = 0.041) and more frequent voluntary bowel movements (P = 0.035). There were no differences in other measures of fecal incontinence severity.

CONCLUSIONS

Shorter proximal extended margins beyond the adequate ganglionated margin do not significantly impact post-operative complication rates and have an unclear effect on fecal incontinence.

TYPE OF STUDY

Case Control.

LEVEL OF EVIDENCE

Level III.

The Junction Between the Peristaltic and Non-peristaltic Bowel (Shore Break) is Found in the Transition Zone in Hirschsprung's Disease

BACKGROUND

The junction between the peristaltic and non-peristaltic bowel, which is named the "shore break" (SB), observed on endoscopy is thought to be the boundary between normal and abnormal motility in Hirschsprung's disease (HD). The transition zone (TZ), which is the histopathological border, does not have normal motility and should be resected. This study aimed to evaluate the histopathological findings of the SB and determine the association between the SB and TZ.

METHODS

A retrospective review of surgical specimens of patients with HD who underwent preoperative SB marking was conducted. The TZ was defined if nerve hypertrophy, myenteric hypoganglionosis, or partial circumferential aganglionosis was detected.

RESULTS

Ten patients (9 boys and 1 girl) were studied. The median age at surgery was 30 days. The median distance from the anal verge to the marked SB site was 14 cm. No patients manifested any obstructive symptoms resulting from a residual TZ bowel. In eight patients, nerve hypertrophy was identified at the proximal margin and at the SB. Myenteric hypoganglionosis was identified in three patients at the proximal margin and SB. Partial circumferential aganglionosis was identified at the SB in two patients. As a result, in all patients, the pull-through site and SB site had histopathological features indicating TZ.

CONCLUSIONS

The SB is located in the TZ. Our results suggest that the proximal part of the TZ has normal motility and that functional border points may be present in the TZ.

LEVEL OF EVIDENCE

IV.

Histopathology of Ganglion Cells in the Proximal Resected Bowel Correlates With the Clinical Outcome in Hirschsprung Disease: A Pilot Study

INTRODUCTION

Intraoperative leveling biopsy by identifying ganglion cells is crucial to determine surgical margin during surgery for Hirschsprung disease (HSCR). The anastomosis should be performed at least 5 cm proximal to the ganglionic segment to prevent transition zone pull-through. However, the length of the transition zone could be much longer than expected and the histological evaluation of the entire circumference of the proximal margin is recommended, which is time-consuming and not applicable for leveling biopsy. We found that the histopathologic features of ganglion cells varied in the examined bowel specimens and demonstrated a pattern similar to immature and degenerated neuron cells. We assumed that the histopathologic features of ganglion cells in the proximal resected bowel were associated with the clinical outcome and might guide the leveling biopsy. In this study, we described a histopathologic grade of ganglion cells based on the degree of maturity and degeneration. We assessed the correlation between the histopathological grade of ganglion cells in the proximal surgical margin and clinical outcome.

METHODS

Three hundred fifty seven patients with HSCR treated between 2013 and 2020 were included. The ganglion cells were divided into six grades based on the histopathologic features in frozen sections. Medical records and detailed histopathologic results of intraoperative frozen sections were reviewed. Follow-up data were collected to evaluate clinical outcomes. The pediatric incontinence and constipation scoring system was used to predict bowel function.

RESULTS

The histopathologic results of proximal resected bowel from 357 HSCR patients were presented as follows: Grade I in 52 patients (14.6%), Grade II in 186 patients (52.1%), Grade III in 107 patients (30.0%), and Grade IV in 12 patients (3.4%). The median follow-up time was 46.8 mo (13.0-97.6 mo). The histopathologic grade of ganglion cells from the proximal resected margin was significantly related to postoperative constipation problems and the incidence of Hirschsprung-associated enterocolitis. The results from the pediatric incontinence and constipation scoring system indicated a positive correlation between better postoperative bowel function and lower histopathologic grade of ganglion cells.

CONCLUSIONS

This pilot study showed an association between the histopathologic features of ganglion cells in the proximal surgical margin and the clinical outcome. It may provide additional information for intraoperative pathologic consultation in leveling biopsy to prevent insufficient resection of the affected colon. A prospective study is warranted to validate these findings before clinical application.

Hirschsprung Disease for the Practicing Surgical Pathologist

OBJECTIVES

Hirschsprung disease (HD) is a congenital condition defined by the absence of ganglion cells in the distal-most portion of the gastrointestinal tract. Biopsies and resections for HD can be adrenaline inducing for the general surgical pathologist because specimens are infrequent; HD is 1 of only a few neuroanatomic diseases that general surgical pathologists diagnose; numerous preanalytic factors (eg, biopsy adequacy, surgeon sampling protocol, processing artifacts) can affect histologic interpretation; and most importantly, the diagnosis has high stakes.

METHODS

We provide a comprehensive overview of the background, relevant clinical procedures, and pathologic assessment of HD. Grossing and frozen section protocols, an algorithmic approach to diagnosis, and histologic pearls and pitfalls are also discussed.

RESULTS

Evaluation and recognition of the features of HD have evolved significantly in the past 2 decades with the discovery of the value of calretinin immunohistochemistry in the late 2000s and the recent development of straightforward and reproducible histologic criteria for identification of the HD transition zone.

CONCLUSIONS

These advancements have substantially improved the pathologist's ability to reliably evaluate for HD. Nonetheless, as with any high-stakes surgical pathology specimen, clear communication with the clinical team is essential.

Bowel function at preschool and early childhood age in children with long-segment Hirschsprung disease

Bowel dysfunction has been proven to be the most typical complication of long-segment Hirschsprung disease (LSHD). Additionally, bowel dysfunction in preschool and early childhood should be properly assessed, because it may result in persistent bowel dysfunction, social issues, and depression in adolescence and adulthood. This study evaluated bowel function during preschool and early childhood in patients with LSHD. A cross-sectional bowel function score (BFS) questionnaire survey was conducted on 270 infants with short-segment Hirschsprung disease (SSHD) and LSHD who underwent pull-through (PT) between January 2014 and December 2019 at the Children's Hospital of Nanjing Medical University. One hundred ninety patients who consented to the survey were asked to complete the questionnaire and were divided into two groups: the LSHD group (n = 42) and the SSHD group (n = 148). Bowel function outcomes were assessed by using a questionnaire. The total BFS score in the LSHD group was significantly lower than that in the SSHD group (15.0 [14.0, 17.0] vs. 18.0 [16.0, 19.0], p < 0.05) and did not improve with age (p > 0.05). Independent BFS items with lower scores were discovered in LSHD than in SSHD, including the capacity to hold back defecation, feeling/reporting the urge to defecate, frequency, soiling, and accidents (all p < 0.05). After subgroup analysis of follow-up age (3-5 years, 5 ~ 7 years, and > 7 years), there was no difference between the score of ability to hold back defecation over 7 years old and feeling/reporting the urge to defecate over 5 years old (all p > 0.05). The frequency and soiling scores were lower in the LSHD group than in the SSHD group over 5 years of age (all p < 0.05). Fortunately, there was no difference in constipation scores and social problems between the LSHD and SSHD groups in every sub-follow-up group (all p > 0.05).  Conclusion: Overall, bowel function at preschool and early childhood age was poorer in LSHD than in SSHD and did not improve with age. However, the ability to hold back defecation and feeling/reporting the urge to defecate with age in LSHD may be similar to those in SSHD. Simultaneously, the frequency, soiling, and number of accidents were consistently worse in the LSHD group.  Trial registration: This study was retrospectively registered in the ClinicalTrials database.gov (NCT05461924) in August 2022. What is Known: • Bowel function in SSHD is satisfactory or near-normal, and the general consensus is that the longer the aganglionic segment, the worse the bowel function after surgery. • Bowel functional outcomes of LSHD were not defined, and the limited reports of bowel functional outcomes compared with SSHD were extensively varied. Bowel dysfunction at preschool and early childhood may lead to persistent bowel dysfunction, social problems, and depression in adolescence or adulthood. What is New: • Bowel function in preschool and early childhood in patients with LSHD has not been defined and should be thoroughly assessed in a larger group of patients with precise definitions of incontinence or soiling. • The present study was primarily designed to evaluate bowel function at preschool and early childhood age in LSHD compared with SSHD in a relatively large number of HD cases using BFS.

The transition zone in Hirschsprung's bowel contains abnormal hybrid ganglia with characteristics of extrinsic nerves

The aganglionic bowel in short-segment Hirschsprung's disease is characterized both by the absence of enteric ganglia and the presence of extrinsic thickened nerve bundles (TNBs). The relationship between the TNBs and the loss of enteric ganglia is unknown. Previous studies have described decreasing numbers of ganglia with increasing density of TNBs within the transition zone (TZ) between ganglionic and aganglionic gut, and there is some evidence of spatial contact between them in this region. To determine the cellular interactions involved, we have analysed the expression of perineurial markers of TNBs and enteric ganglionic markers for both neural cells and their ensheathing telocytes across four cranio-caudal segments consisting of most proximal ganglionic to most distal aganglionic from pull-through resected colon. We show that in the TZ, enteric ganglia are abnormal, being surrounded by perineurium cells characteristic of TNBs. Furthermore, short processes of ganglionic neurons extend caudally towards the aganglionic region, where telocytes in the TNB are located between the perineurium and nerve fibres into which they project telopodes. Thus, enteric ganglia within the TZ have abnormal structural characteristics, the cellular relationships of which are shared by the TNBs. These findings will help towards elucidation of the cellular mechanisms involved in the aetiology of Hirschsprung's disease.

Histopathological dimensions differ between aganglionic and ganglionic bowel wall in children with Hirschsprung's disease

BACKGROUND

In the validation of new imaging technology for children with Hirschsprung's disease (HSCR), basic anatomical parameters of the bowel wall must be established specifically for this patient group.

AIM

To explore differences in histoanatomical layers of bowel wall, comparing ganglionic and aganglionic bowel walls, and to examine if the bowel wall thickness is linked to patient weight.

METHODS

This was an observational study of bowel specimens from children weighing 0-10 kg, operated on consecutively during 2018-2020. Ganglionic and aganglionic bowel walls were measured in digitalized microscopy images from 10 sites per trans-sectional specimen and compared regarding the thickness of their histoanatomical layers.

RESULTS

Bowel walls were measured in 21 children. Full bowel wall thickness did not differ between aganglionic and ganglionic bowel (2.20 vs 2.04; p = 0.802) while weight at surgery correlated positively with both ganglionic and aganglionic bowel wall thickness (r = 0.688 and 0.849, respectively), and age at surgery with ganglionic bowel wall thickness (r = 0.517). In aganglionic segments, the muscularis externa layer was thicker compared to that in ganglionosis (0.45 vs 0.31 mm, p = 0.012) whereas the muscularis interna was thinner (0.45 vs 0.62 mm, p < 0.001). A diagnostic index was identified whereby a lower ratio of muscularis interna/externa thickness followed by a thinner muscularis interna differed between aganglionic and ganglionic bowel in all specimens.

CONCLUSION

Thicknesses of the bowel wall's muscle layers differ between aganglionic and ganglionic bowel walls in children with HSCR. These findings support a diagnostic index that could be validated for transfer to instant diagnostic imaging techniques.

LEVEL OF EVIDENCE

Diagnostic: 3.

Translational research in Hirschprung's disease at the National Children's Research Centre in Dublin

Hirschsprung's disease (HD) is a congenital condition characterised by aganglionosis in the distal bowel. Over the years, at the National Children's Research Centre (NCRC), HD has been one of the most prominent and successful research areas for Prof. Prem Puri's research team. Research fellows from around the world came to the NCRC to work on both animal and human studies of HD and, cumulatively, made important discoveries in this field, publishing a total of 144 HD articles in peer-reviewed journals. Through their published work, the NCRC has been recognised as the leading international centre for the investigation of HD and its allied disorders. In this review, I will summarise the main findings from this work.

Determining the correct resection level in patients with Hirschsprung disease using contrast enema and full thickness biopsies: Can the diagnostic accuracy be improved by examining submucosal nerve fiber thickness?

BACKGROUND

Intraoperative resection level in patients with Hirschsprung disease (HD) is determined by contrast enema, surgeon's intraoperative judgement and full thickness biopsy (FTB) identifying ganglia. This study aims to evaluate diagnostic accuracy of contrast enema and FTB in determination of resection level and whether this can be improved by measuring submucosal nerve fiber diameter.

METHODS

We retrospectively analyzed contrast enema and intraoperative FTBs obtained in our center, determining diagnostic accuracy for level of resection. Gold standard was pathological examination of resection specimen. Secondly, we matched transition zone pull-through (TZPT) patients with non-TZPT patients, based on age and length of resected bowel, to blindly compare nerve fibers diameters between two groups using group comparison.

RESULTS

From 2000-2021, 209 patients underwent HD surgery of whom 180 patients (138 males; median age at surgery: 13 weeks) with 18 TZPTs (10%) were included. Positive predictive value of contrast enema was 65.1%. No caliber change was found in patients with total colon aganglionosis (TCA). Negative predictive value of surgeon's intraoperative judgement and FTB in determining resection level was 79.0% and 90.0% (91.2% single-stage, 84.4% two-stage surgery) respectively. Mean nerve fiber diameter in TZPT was 25.01 µm (SD= 5.63) and in non-TZPT 24.35 µm (SD= 6.75) (p = 0.813).

CONCLUSION

Determination of resection level with combination of contrast enema, surgeon's intraoperative judgement and FTB results in sufficient diagnostic accuracy in patients with HD. If no caliber change is seen with contrast enema, TCA should be considered. Resection level or transition zone cannot be determined by assessment of submucosal nerve fiber diameter in FTB.

TYPE OF STUDY

clinical research paper.

A Novel Method for Identifying the Transition Zone in Long-Segment Hirschsprung Disease: Investigating the Muscle Unit to Ganglion Ratio

Hirschsprung disease (HSCR) is characterised by the absence of enteric ganglia along variable lengths of the distal bowel. Current gold standard treatment involves the surgical resection of the defective, aganglionic bowel. Clear and reliable distinction of the normoganglionated bowel from the transition zone is key for successful resection of the entire defective bowel, and the avoidance of subsequent postoperative complications. However, the intraoperative nature of the tissue analysis and the variability of patient samples, sample preparation, and operator objectivity, make reproducible identification of the transition zone difficult. Here, we have described a novel method for using muscle units as a distinctive landmark for quantifying the density of enteric ganglia in resection specimens from HSCR patients. We show that the muscle unit to ganglion ratio is greater in the transition zone when compared with the proximal, normoganglionated region for long-segment HSCR patients. Patients with short-segment HSCR were also investigated, however, the muscle unit to ganglion ratio was not significantly different in these patients. Immunohistochemical examination of individual ganglia showed that there were no differences in the proportions of either enteric neurons or glial cells through the different regions of the resected colon. In addition, we identified that the size of enteric ganglia was smaller for patients that went on to develop HSCR associated enterocolitis; although the density of ganglia, as determined by the muscle unit to ganglia ratio, was not different when compared with patients that had no further complications. This suggests that subtle changes in the enteric nervous system, even in the “normoganglionated” colon, could be involved in changes in immune function and subsequent bacterial dysbiosis.

The Length of the Transition Zone in Patients with Rectosigmoid Hirschsprung Disease

Background: The transition zone (TZ) is defined by specific histological findings in patients with Hirschsprung Disease (HSCR). HSCR treatment includes surgical removal of the aganglionic zone (AZ). During the pull-through procedure, it is critical to resect the TZ. Given the TZ’s wide histological heterogeneity, we wanted to know how extensive the histological transition zone is. Methods: A retrospective study of patients who had pull-through surgery for rectosigmoid HSCR between January 2010 and December 2020 was carried out. Demographics, length of TZ and AZ, age and symptoms upon presentation, and complications after surgery were also obtained. Results: The inclusion criteria were met by 50 patients. The mean age of all patients was 10 months (0.1–107.5 months), with a mean age at pull-through of 16.3 months (3–112 months). Thirty-one out of fifty patients (62%) received primary laparoscopic endorectal pull-through surgery (LEPT). The average TZ length of all patients was 2.6 cm (0–10 cm), and the AZ length was 9.6 cm (1–30 cm). The length of the AZ and TZ were shown to have no correlation (r² = 0.237). Conclusions: The current study found that the mean length of the TZ in individuals with rectosigmoid HSCR is less than 5 cm in most cases and has no correlation with the length of the AZ.

The utility of the 24-h delayed film of barium enema for detecting the dysganglionic bowel segment in Hirschsprung's disease

BACKGROUND

Preoperative evaluation of the dysganglionic bowel segment is critical for establishing the optimal resection strategy for Hirschsprung's disease (HSCR), which facilitates patient outcomes.

OBJECTIVE

We set out to determine the utility of the 24-h delayed film of barium retention in predicting the length of dysganglionic bowel segment in HSCR.

MATERIALS AND METHODS

A retrospective study of patients with clinically suspicious HSCR who underwent a preoperative 24-h delayed film of barium enema and were surgically treated from January 2015 to December 2019 was conducted.

RESULTS

Two hundred and 58 patients were enrolled in this study. The sensitivity, specificity, positive and negative predictive values (NPVs) of the 24-h delayed film of barium enema to predict the neuropathological segment were 89.1, 91.5, 91.3, and 89.4%, respectively. The Youden index was 80.6%, with a kappa value of 0.806 (P < 0.001). The correlation rate between barium retention level and pathological results was 72.7% (16/22) when aganglionosis was restricted within the mid-distal rectum (short-segment type), increasing to 92.0% (46/50) and 93.5% (174/186) for patients that had aganglionosis extended beyond the mid-distal rectum (classical type) and sigmoid colon (long-segment type), respectively. Lastly, patients younger than 3 months showed a lower correlation rate (72.2%) compared to patients aged 3-12 months (91.0%) and > 12 months (92.6%).

CONCLUSIONS

Our investigation of the 24-h delayed film of barium enema performed for patients suspected of having HSCR indicated that the barium retention level remains crucial in predicting dysganglionic bowel segment, which contributes to the decision-making for surgical physicians.

Ultra high frequency ultrasonography to distinguish ganglionic from aganglionic bowel wall in Hirschsprung disease: A first report

BACKGROUND/PURPOSE

In Hirschsprung disease (HD) surgery, confirming ganglionic bowel is essential. A faster diagnostic method than the current frozen biopsy is desirable. This study investigated whether aganglionic and ganglionic intestinal wall can be distinguished from each other by ultra high frequency ultrasound (UHF ultrasound).

METHODS

In an HD center during 2019, intestinal walls of recto-sigmoid specimens from HD patients were examined ex vivo with a 70 MHz UHF ultrasound transducer. Data from four sites were described. Histopathologic analysis was compared to the ultrasonography outcome at each site. Each patient's specimen served as its own control.

RESULTS

11 resected recto-sigmoid specimens (median 20 cm long [range 6.5-33]) with transition zones of 5 cm (2-11 cm) were taken from children aged 22 days (13-48) weighing 3668 g (3500-5508); 44 key sites were analyzed. There was full concordance for 42/44 (95%) key sites and 10 of 11 (91%) specimens. The specimen with discordance of two key sites contained a segment of aganglionosis (3 cm) and a transition zone (1 cm): the site discordance was limited to the transition zone ends.

CONCLUSIONS

This first report on UHF ultrasound in recto-sigmoid HD shows promising results in identifying aganglionosis, transition zones and ganglionic bowel. Further in vivo studies are required.

Long-term outcomes in children with Hirschsprung's disease and transition zone bowel pull-through: impact of surgical techniques and role for conservative approach

PURPOSE

Presence of transition zone (TZ) in the pulled colon can impact the outcome of surgery in children with Hirschsprung's disease. There is a wide variation in terminology used to define TZ and its management. We present our series of managing 11 such children with considerations for conservative management.

METHODS

Eleven of 114 children operated for Hirschsprung's disease had features of TZ on the 4-quadrant doughnut assessment of proximal anastomosing margin. They were followed up for development of obstructive symptoms, failure of pull-through procedure or bowel-related complications. Intervention done were observation with laxatives, dilatation, Botox injection and redo pull-through.

RESULTS

Of the 11 children, 6 underwent Duhamel's procedure and 5, transanal endorectal pull-through (TERP). Features identified on HPE were presence of hypertrophic nerve bundles involving 2 or 3 quadrants in the circumferential doughnut biopsy of proximal anastomosing margin. Observed symptoms included constipation, enterocolitis, increased bowel frequency and soiling. Intervention done were use of laxatives with bowel management program in six and Botox injections in four. Only one child with TZ in 3 quadrants required redo surgery. Mean follow-up was 5.2 years with resolution of symptoms in most.

CONCLUSION

This study highlights the role of conservative management with good outcomes in children with TZ bowel pull-through having hypertrophic nerve fibers and normal ganglion pattern. Children who underwent Duhamel's procedure had little impact with the presence of TZ at anastomotic margin and majority of those undergoing TERP benefitted from Botox injection. Conservative management can be attempted successfully to prevent redo surgical interventions as they can lead to poorer outcomes. Only those children not responding to conservative measures need to be planned for revision surgery.

Persistent bowel dysfunction after surgery for Hirschsprung’s disease: A neuropathological perspective

Hirschsprung’s disease (HD) is a congenital disorder, characterized by aganglionosis in the distal part of the gastrointestinal tract. Despite complete surgical resection of the aganglionic segment, both constipation and fecal incontinence persist in a considerable number of patients with limited treatment options. There is growing evidence for structural abnormalities in the ganglionic bowel proximal to the aganglionosis in both humans and animals with HD, which may play a role in persistent bowel dysfunction. These abnormalities include: (1) Histopathological abnormalities of enteric neural cells; (2) Imbalanced expression of neurotransmitters and neuroproteins; (3) Abnormal expression of enteric pacemaker cells; (4) Abnormalities of smooth muscle cells; and (5) Abnormalities within the extracellular matrix. Hence, a better understanding of these previously unrecognized neuropathological abnormalities may improve follow-up and treatment in patients with HD suffering from persistent bowel dysfunction following surgical correction. In the long term, further combination of clinical and neuropathological data will hopefully enable a translational step towards more individual treatment for HD.

What is the appropriate aganglionic bowel length on contrast enema for attempting single stage transanal endorectal pull-through in Hirschsprung disease?

PURPOSE

To identify influence of different values of age and abnormal bowel length in HD patients selected for single stage TERPT which affects the technique of surgery.

METHODS

This observational study was carried out for over 2.5 years. All children younger than 14 years old with clinical suspicion for HD, typical transitional zone (TZ) on contrast enema (CE) distal to splenic flexure, preoperative diagnosis approved by full thickness biopsy, no previous surgical history and no urgency were included. The distance between the anus and TZ was considered as aganglionic length on CE. Biopsy was taken from distal to proximal of resected bowel to reach circumferentially normal innervated bowel. Paired sample Student's t-test, Pearson correlation test, receiver operating characteristic (ROC) analysis were performed.

RESULTS

Forty-eight patients were enrolled in this study. Measured mean for aganglionic bowel length on CE and pathology were 33.5 ± 17.1 cm and 56.8 ± 33.5 cm, respectively (p < 0.01). Correlation coefficient (R) and coefficient of determination (R2) were 0.632 and 40%, respectively (p < 0.01). The difference between radiologic and pathologic measurements in females was higher than males (mean: 29.3 vs 21.9 cm) but was not statistically significant (p = 0.75). There was statistically significant difference between CE and pathologic results in the infants younger than 10 months (p = .004). Abnormal bowel length equal to 52 cm predicted requirement of laparoscopy assistance/laparotomy with 75% sensitivity and 85% specificity.

CONCLUSION

Our investigation showed it is safe to attempt for single stage TERPT when aganglionic length on CE is less than 52 cm and the child with HD is older than 10 months. Chance of requiring additional laparotomy or laparoscopy assistance is low in these patients.

TYPE OF STUDY

Study of diagnostic test.

LEVEL OF EVIDENCE

Level II.

Routine use of Circumferential 'Doughnut' Biopsy in Pull through Surgery for Hirschsprung's Disease: Advantages and Limitations

Aims:

The aim of this study was to review the use of the on-table “doughnut” biopsy for frozen section assessment of bowel in the operative management of Hirschsprung's disease (HD).

Methods:

This was a single-center retrospective review of doughnut histopathology reports, operation notes, and slides from 2010 to 2017. Data were assessed for the presence of transition zone (TZ) features and the subsequent decision as to the level of pull-through.

Results:

Fifty-five patients had a doughnut biopsy taken as part of their intraoperative frozen section histopathology for pull-through for HD during the study period. Forty-eight required a single doughnut, six required a second more proximal doughnut, and one required a third doughnut. Of the 55 first doughnuts, 37 were identified as normal bowel, 17 were TZ, and not defined in the report in one case. Of the 17 TZ doughnuts, 8 were accepted for pull-through and 7 underwent second doughnuts (normal = 4 and TZ = 3). The third doughnut (one case) was normal. TZ was accepted for pull-through in 10/54 (18.5%) patients despite the use of a doughnut. However, TZ was avoided in six (11.1%), where the single-point biopsy was “normal.”

Conclusions:

The doughnut allows the entire circumference of pull-through level to be assessed, enabling TZ identification that can be missed by single seromuscular biopsies. This allows identification and avoidance of TZ pull-through, although sometimes, it is accepted for other reasons.

Automatic ganglion cell detection for improving the efficiency and accuracy of hirschprung disease diagnosis

Histopathologic diagnosis of Hirschsprung's disease (HSCR) is time consuming and requires expertise. The use of artificial intelligence (AI) in digital pathology is actively researched and may improve the diagnosis of HSCR. The purpose of this research was to develop an algorithm capable of identifying ganglion cells in digital pathology slides and implement it as an assisting tool for the pathologist in the diagnosis of HSCR. Ninety five digital pathology slides were used for the construction and training of the algorithm. Fifty cases suspected for HSCR (727 slides) were used as a validation cohort. Image sets suspected to contain ganglion cells were chosen by the algorithm and then reviewed and scored by five pathologists, one HSCR expert and 4 non-experts. The algorithm was able to identify ganglion cells with 96% sensitivity and 99% specificity (in normal colon) as well as to correctly identify a case previously misdiagnosed as non-HSCR. The expert was able to achieve perfectly accurate diagnoses based solely on the images suggested by the algorithm, with over 95% time saved. Non-experts would require expert consultation in 20–58% of the cases to achieve similar results. The use of AI in the diagnosis of HSCR can greatly reduce the time and effort required for diagnosis and improve accuracy.

Histopathological perspective of the pulled-through colon in Hirschsprung disease: Impact on clinical outcome

BACKGROUND

The outcome in HD has not been always satisfactory even after a technically sound operation.

PURPOSE

To define the characteristic histopathological features of the pulled-through colon in patients with HD, and it is impact on clinical outcome.

PATIENTS AND METHODS

The study included patients with HD who underwent surgical repair between 2010 through 2016. The proximal margin of resected bowel segments (which corresponds to the pulled through colon) was subjected to detailed histopathological examination by two experienced pathologists. Based on the frequency of postoperative attacks of HAEC (fever, vomiting, abdominal distention, fluid offensive stools), cases included in the study were divided into two groups: Group A, those with less frequent attacks of HAEC; and Group B, those with recurrent attacks of HAEC (more than 3).

RESULTS

The study included 35 patients (25 in group A; and 10 in group B). Their age ranged from 0.2 to 144 months (median 6 months). Comparing the histopathological findings in the two clinical groups, we have found that Group B (recurrent attacks of HAEC) had significantly more frequent focal disarray of nerve bundles and thicker nerve bundle diameter. Also, histopathological features of acute inflammation were more prevalent in examined specimens from group B.

CONCLUSION

Several histopathological features of the examined bowel specimens in HD, other than presence or absence of ganglion cells, are indicative of postoperative functional outcome. These include the thickness and maturity of nerve bundles, in addition to the presence of histopathological features of acute inflammation.

LEVEL OF EVIDENCE

This is a case control study (level III evidence).

Laparoscopic-Assisted Transanal Pull-Through in Hirschsprung Disease: Does Laparoscopic Dissection Minimize Anal Overstretching?

Introduction: Surgical treatment for Hirschsprung disease (HD) has evolved from a staged repair to a primary operation but is still associated with significant complications. Extensive transanal dissection may overstretch the sphincter and cause partial tear; however, laparoscopic dissection can decrease rectal overstretching. Thus, this study aimed to evaluate the outcome of surgical management of HD and the efficacy of laparoscopic-assisted transanal endorectal pull-through in infants and children in our center. Patients and Methods: We reviewed the medical records of 74 patients who underwent surgical repair of HD from 2006 to 2019. However, we excluded 42 patients with HD (patients with stoma [n = 33] and total colonic aganglionosis [n = 9]). The remaining 32 patients were divided into two groups. Group A included patients who had transanal pull-through with laparoscopic assistance only to visualize the transition zone, take a biopsy, and check for twisting or bleeding. Group B included patients who had laparoscopic-assisted transanal pull-through with dissection of the rectum. All patients had Soave repair with an approximate cuff length of 5 cm. Results: Group A included 18 patients, whereas group B included 14 patients. Demographic data were comparable between the two groups with no significant difference in age or gender (P = .12 and .67, respectively). Patients in group A had longer operative time (210 ± 20.75 minutes versus 178 ± 18.92 minutes; P < .001) and hospital stay (6 ± 1.33 days versus 5 ± 1.24 days; P = .033). No significant difference was observed in postoperative complications between both groups (anastomotic site stricture, P = .295; persistent soiling, P = .238). Conclusion: Laparoscopic rectal dissection for managing HD is associated with less operative time and hospital stay. In addition, all procedures required for the repair can be safely performed using laparoscopy.