Histology of the Transition Zone in Hirschsprung Disease

Approach to Constipation in Children: Recommendations for Evaluation and Management

Constipation is common in childhood, and most patients can be successfully managed by their primary care provider. However, some patients will require more specialized management either due to an underlying congenital colorectal disorder such as Hirschsprung disease or anorectal malformation or due to severe functional constipation that is refractory to medical management.

Three-Dimensional Imaging of the Enteric Nervous System in Human Pediatric Colon Reveals New Features of Hirschsprung's Disease

BACKGROUND & AIMS

Hirschsprung's disease is defined by the absence of the enteric nervous system (ENS) from the distal bowel. Primary treatment is "pull-through" surgery to remove bowel that lacks ENS, with reanastomosis of "normal" bowel near the anal verge. Problems after pull-through are common, and some may be due to retained hypoganglionic bowel (ie, low ENS density). Testing this hypothesis has been difficult because counting enteric neurons in tissue sections is unreliable, even for experts. Tissue clearing and 3-dimensional imaging provide better data about ENS structure than sectioning.

METHODS

Regions from 11 human colons and 1 ileal specimen resected during Hirschsprung's disease pull-through surgery were cleared, stained with antibodies to visualize the ENS, and imaged by confocal microscopy. Control distal colon from people with no known bowel problems were similarly cleared, stained, and imaged.

RESULTS

Quantitative analyses of human colon, ranging from 3 days to 60 years old, suggest age-dependent changes in the myenteric plexus area, ENS ganglion area, percentage of myenteric plexus occupied by ganglia, neurons/mm2, and neuron Feret's diameter. Neuron counting using 3-dimensional images was highly reproducible. High ENS density in neonatal colon allowed reliable neuron counts using 500-μm2 × 500-μm2 regions (36-fold smaller than in adults). Hirschsprung's samples varied 8-fold in proximal margin enteric neuron density and had diverse ENS architecture in resected bowel.

CONCLUSIONS

Tissue clearing and 3-dimensional imaging provide more reliable information about ENS structure than tissue sections. ENS structure changes during childhood. Three-dimensional ENS anatomy may provide new insight into human bowel motility disorders, including Hirschsprung's 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.

Transition Zone Pull-through in Patients with Hirschsprung Disease: Is Redo Surgery Beneficial for the Long-term Outcomes?

INTRODUCTION

Transition zone pull-through (TZPT) is incomplete removal of the aganglionic bowel/transition zone (TZ) in patients with Hirschsprung disease (HD). Evidence on which treatment generates the best long-term outcomes is lacking. The aim of this study was to compare the long-term occurrence of Hirschsprung associated enterocolitis (HAEC), requirement of interventions, functional outcomes and quality of life between patients with TZPT treated conservatively to patients with TZPT treated with redo surgery to non-TZPT patients.

METHODS

We retrospectively studied patients with TZPT operated between 2000 and 2021. TZPT patients were matched to two control patients with complete removal of the aganglionic/hypoganglionic bowel. Functional outcomes and quality of life was assessed using Hirschsprung/Anorectal Malformation Quality of Life questionnaire and items of Groningen Defecation & Continence together with occurrence of Hirschsprung associated enterocolitis (HAEC) and requirement of interventions. Scores between the groups were compared using One-Way ANOVA. The follow-up duration lasted from time at operation until follow-up.

RESULTS

Fifteen TZPT-patients (six treated conservatively, nine receiving redo surgery) were matched with 30 control-patients. Median duration of follow-up was 76 months (range 12-260). No significant differences between groups were found in the occurrence of HAEC (p = 0.65), laxatives use (p = 0.33), rectal irrigation use (p = 0.11), botulinum toxin injections (p = 0.06), functional outcomes (p = 0.67) and quality of life (p = 0.63).

CONCLUSION

Our findings suggest that there are no differences in the long-term occurrence of HAEC, requirement of interventions, functional outcomes and quality of life between patients with TZPT treated conservatively or with redo surgery and non-TZPT patients. Therefore, we suggest to consider conservative treatment in case of TZPT.

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.

The Prevalence and Clinical Impact of Transition Zone Anastomosis in Hirschsprung Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Hirschsprung disease (HD) is characterized by absent neuronal innervation of the distal colonic bowel wall and is surgically treated by removing the affected bowel segment via pull-through surgery (PT). Incomplete removal of the affected segment is called transition zone anastomosis (TZA). The current systematic review aims to provide a comprehensive overview of the prevalence and clinical impact of TZA.

METHODS

Pubmed, Embase, Cinahl, and Web of Sciences were searched (last search: October 2020), and studies describing histopathological examination for TZA in patients with HD were included. Data were synthesized into aggregated Event Rates (ER) of TZA using random-effects meta-analysis. The clinical impact was defined in terms of obstructive defecation problems, enterocolitis, soiling, incontinence, and the need for additional surgical procedures. The quality of studies was assessed using the Newcastle-Ottawa Scale.

KEY RESULTS

This systematic review included 34 studies, representing 2207 patients. After excluding series composed of only patients undergoing redo PT, the prevalence was 9% (ER = 0.09, 95% CI = 0.05-0.14, p < 0.001, I2 = 86%). TZA occurred more often after operation techniques other than Duhamel (X2 = 19.21, p = <0.001). Patients with TZA often had obstructive defecation problems (62%), enterocolitis (38%), soiling (28%), and fecal incontinence (24%) in follow-up periods ranging from 6 months to 13 years. Patients with TZA more often had persistent obstructive symptoms (X2 = 7.26, p = 0.007).

CONCLUSIONS AND INFERENCES

TZA is associated with obstructive defecation problems and redo PT and is thus necessary to prevent.

CXCR4 and CXCL12 signaling regulates the development of extrinsic innervation to the colorectum

The gastrointestinal tract is innervated by an intrinsic neuronal network, known as the enteric nervous system (ENS), and by extrinsic axons arising from peripheral ganglia. The nerve of Remak (NoR) is an avian-specific sacral neural crest-derived ganglionated structure that extends from the cloaca to the proximal midgut and, similar to the pelvic plexus, provides extrinsic innervation to the distal intestine. The molecular mechanisms controlling extrinsic nerve fiber growth into the gut is unknown. In vertebrates, CXCR4, a cell-surface receptor for the CXCL12 chemokine, regulates migration of neural crest cells and axon pathfinding. We have employed chimeric tissue recombinations and organ culture assays to study the role of CXCR4 and CXCL12 molecules in the development of colorectal innervation. CXCR4 is specifically expressed in nerve fibers arising from the NoR and pelvic plexus, while CXCL12 is localized to the hindgut mesenchyme and enteric ganglia. Overexpression of CXCL12 results in significantly enhanced axonal projections to the gut from the NoR, while CXCR4 inhibition disrupts nerve fiber extension, supporting a previously unreported role for CXCR4 and CXCL12 signaling in extrinsic innervation of the colorectum.

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.

Pediatric colorectal robotic surgery

Robotic colorectal surgery allows adult and pediatric surgeons to overcome the technical limitations of laparoscopic surgery. It also provides improved ergonomics in the field of surgery. Robotic surgery has several advantages in colorectal operations that require complex minimally invasive skills including anorectal malformations, Hirschsprung disease, and inflammatory bowel disease. In this section, we discuss the key aspects of colorectal surgery where robotic instrumentation seems ideal.

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.

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.

Adult patients with allied disorders of Hirschsprung’s disease in emergency department: An 11-year retrospective study

BACKGROUND

In the past years, only a few studies with a limited number of adult patients analyzed clinical features of allied disorders of Hirschsprung’s disease (ADHD), most of which were individual case reports or lacked detailed clinical information. Although many studies have reported patients presenting to the emergency department (ED) with recurrent abdominal symptoms for a number of disorders, there are few data involving ADHD. However, owing to a lack of awareness of the disease, misdiagnoses and mistreatments are common. Severe complications such as perforation, bleeding, malabsorption, and even death in ADHD had been reported by many studies.

AIM

To assist ED clinicians in having a more comprehensive understanding of this disease and making an early suspected diagnosis of ADHD more effectively.

METHODS

We enrolled 53 patients who visited the ED and were eventually diagnosed with ADHD over the past 11 years in our hospital. Their basic information, clinical manifestations, and imaging findings were analyzed. Blood indices were compared between the ADHD and irritable bowel syndrome (IBS) groups.

RESULTS

Adult patients with ADHD had a mean age of 48.8 ± 14.3 years, and 77.4% had been treated before admission. The transverse colon was the most common dilated part (73.6%), and constipation (67.9%) was the most common symptom. ADHD patients can present with uncommon symptoms and false-negative imaging findings. Logistic regression analysis indicated that body mass index (BMI) [odds ratio (OR) = 0.786, P = 0.013], cholinesterase (per 1000 units; OR = 0.693, P = 0.008), and blood chlorine (OR = 0.816, P = 0.022) were determined to be independent related factors between the ADHD and IBS groups. The area under the receiver operating characteristics curve of these three indices combined was 0.812 (P < 0.001).

CONCLUSION

Emergency physicians should be vigilant regarding patients with chronic constipation, abdominal pain, or abdominal distension, and consider the possibility of ADHD despite its rarity. Abdominal computed tomography examination is recommended as a useful tool in the suspected diagnosis of ADHD. BMI, cholinesterase, and blood chlorine have good discriminative abilities between ADHD and IBS. The nutritional status of adult patients with ADHD is worthy of further attention. Surgical treatment for adult patients with ADHD is important and inevitable.

Characterization of the Transition Zone in Short Segment Hirschsprung Disease Using Calretinin Immunostaining

Introduction: The detailed expression pattern of calretinin immunohistochemistry in the transition zone (TZ) of Hirschsprung disease (HSCR) has not yet been reported. This study aims to examine the value of calretinin immunohistochemistry for more accurately determining the distal and proximal border of the TZ in short segment HSCR. Methods: Specimens of pull-through surgery from 51 patients with short form of HSCR were analyzed on two longitudinal strips using hematoxylin and eosin (H&E) staining and calretinin immunohistochemistry. Results: In all but two patients, the first appearance of calretinin expression was seen on mucosal nerve fibers before the appearance of any ganglion cells, indicating the distal border of the TZ. The maximum distance between the distal border of the TZ and the proximal border of the TZ, defined by ganglion cells in a normal density on H&E stained sections, a strong calretinin expression on mucosal nerve fibers and in >80% of submucosal and myenteric ganglion cells, with no nerve hypertrophy and absence of ganglionitis was 60 mm. Conclusion: The distal border of the TZ is characterized by calretinin positive intramucosal neurites in nearly all of short form of HSCR and not by calretinin expression on ganglion cells.

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.

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.

Skip segment Hirschsprung's disease: diagnostic clues and surgical management

It is challenging to establish a definitive diagnosis and initiate timely management for skip segment Hirschsprung's disease (SSHD). Herein, we report three cases of SSHD at our institution between December 2008 and March 2018. Patient #1 was misdiagnosed and underwent three successive operations within 2 years. Patient #2 and #3 were diagnosed timely based on previous experience. A segmental narrowing detected by barium enema may raise the possibility of SSHD. Laparoscopic-guided multipoint biopsy is regarded as a mini-invasive and purposeful way to take representative samples after locating the segmental narrowing intraoperatively and accurate the final diagnosis. The laparoscopic-assisted pull-through procedure with radical resection from the distal rectum to the most proximal margin of the diseased skip segment is safe and effective in treating patients with SSHD.Level of evidence: Level III.

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.

Diagnosing Hirschsprung disease by detecting intestinal ganglion cells using label-free hyperspectral microscopy

Hirschsprung disease (HD) is a congenital disorder in the distal colon that is characterized by the absence of nerve ganglion cells in the diseased tissue. The primary treatment for HD is surgical intervention with resection of the aganglionic bowel. The accurate identification of the aganglionic segment depends on the histologic evaluation of multiple biopsies to determine the absence of ganglion cells in the tissue, which can be a time-consuming procedure. We investigate the feasibility of using a combination of label-free optical modalities, second harmonic generation (SHG); two-photon excitation autofluorescence (2PAF); and Raman spectroscopy (RS), to accurately locate and identify ganglion cells in murine intestinal tissue without the use of exogenous labels or dyes. We show that the image contrast provided by SHG and 2PAF signals allows for the visualization of the overall tissue morphology and localization of regions that may contain ganglion cells, while RS provides detailed multiplexed molecular information that can be used to accurately identify specific ganglion cells. Support vector machine, principal component analysis and linear discriminant analysis classification models were applied to the hyperspectral Raman data and showed that ganglion cells can be identified with a classification accuracy higher than 95%. Our findings suggest that a near real-time intraoperative histology method can be developed using these three optical modalities together that can aid pathologists and surgeons in rapid, accurate identification of ganglion cells to guide surgical decisions with minimal human intervention.

Phox2b Immunohistochemical Staining in Detecting Enteric Neural Crest Cells in Hirschsprung Disease

BACKGROUND

It can be challenging to recognize undifferentiated/immature ganglion cells, especially single forms. Ganglion cells and glia are derived from enteric neural crest cells (ENCCs), a group of autonomic nervous system (ANS)-lineage neural crest progenitors that PHOX2B regulates. Phox2b is an excellent marker for neoplastic and non-neoplastic ANS cells (eg, peripheral neuroblastic tumors [pNTs]). We hypothesized that Phox2b immunohistochemical staining (IHC) would also be useful for detecting ENCCs.

METHODS

Hematoxylin and eosin, calretinin IHC, and Phox2b IHC were reviewed on 21 pull-through specimens and on a cohort of 12 rectal biopsies.

RESULTS

Phox2b IHC demonstrated nuclear positivity in all of the ganglion cells across the different phases of differentiation without background staining. The Phox2b result correlated with the morphological findings, calretinin IHC results, and diagnoses based on the routine diagnostic method. The intensity was uniformly strong in the undifferentiated/immature forms and became variable in the mature forms; this pattern was similar to that seen in pNTs.

CONCLUSION

Phox2b IHC was highly sensitive and specific for detecting ganglion cells. It worked especially well for immature ganglion cells, seen in premature neonates, and scattered single forms in transition zones. In basic research settings, Phox2b can be a useful marker for early differentiation of ENCCs.

Analysis of enteric nervous system and intestinal epithelial barrier to predict complications in Hirschsprung's disease

In Hirschsprung’s disease (HSCR), postoperative course remains unpredictable. Our aim was to define predictive factors of the main postoperative complications: obstructive symptoms (OS) and Hirschsprung-associated enterocolitis (HAEC). In this prospective multicentre cohort study, samples of resected bowel were collected at time of surgery in 18 neonates with short-segment HSCR in tertiary care hospitals. OS and HAEC were noted during postoperative follow-up. We assessed the enteric nervous system and the intestinal epithelial barrier (IEB) in ganglionic segments by combining immunohistochemical, proteomic and transcriptomic approaches, with functional ex vivo analysis of motility and para/transcellular permeability. Ten HSCR patients presented postoperative complications (median follow-up 23.5 months): 6 OS, 4 HAEC (2 with OS), 2 diarrhoea (without OS/HAEC). Immunohistochemical analysis showed a significant 41% and 60% decrease in median number of nNOS-IR myenteric neurons per ganglion in HSCR with OS as compared to HSCR with HAEC/diarrhoea (without OS) and HSCR without complications (p = 0.0095; p = 0.002, respectively). Paracellular and transcellular permeability was significantly increased in HSCR with HAEC as compared to HSCR with OS/diarrhoea without HAEC (p = 0.016; p = 0.009) and HSCR without complications (p = 0.029; p = 0.017). This pilot study supports the hypothesis that modulating neuronal phenotype and enhancing IEB permeability may treat or prevent postoperative complications in HSCR.

Advances and Pitfalls in the Diagnosis of Hirschsprung Disease

Surgical pathology for Hirschsprung disease (HSCR) occasionally is difficult, especially for those who encounter the disorder infrequently. This article reviews pathologic features of HSCR, considers various specimens the pathologist is required to evaluate, and discusses useful ancillary tests. Potential diagnostic pitfalls are highlighted, and helpful hints are provided to successfully navigate challenging situations. Finally, the article looks forward to new ancillary tests on the horizon and future topics for HSCR research.

Cholinergic innervation and ganglion cell distribution in Hirschsprung's disease

Background

The diagnostic gold standard of Hirschsprung’s disease (HD) is based on the histopathological assessment of colorectal biopsies. Although data on cholinergic innervation and ganglion cell (GC) distribution exist, only few studies have examined these two key features together. We assessed the pattern of cholinergic innervation and the amount of GCs in colorectal specimens of 14 HD patients.

Methods

We established a semi-quantitative score for cholinergic innervation using acetylcholinesterase (AChE) enzyme histochemistry and quantitatively analyzed the number of GCs via NADH tetrazolium reductase (NADH) enzyme histochemistry. We examined both the entire length of the resected specimens as well as defined areas of the transition zone of both pathological and healthy appearing segment.

Results

High AChE score values were associated with absence of GCs, and AChE scores were inversely correlated with the number of GCs. Nevertheless, we observed several cases in which one of the two features revealed a normal distribution pattern, whereas the other still displayed pathological features.

Conclusions

Our data support the need for transmural colon biopsies, to enable the best evaluation of both cholinergic innervation and GCs for a reliable assessment of HD.

Clinical Outcomes After Staged and Primary Laparotomy Soave Procedure for Total Colonic Aganglionosis: a Single-Center Experience from 2007 to 2017

PURPOSE

To compare the clinical outcomes of the staged laparotomy Soave procedure (SLSP) and primary laparotomy Soave procedure (PLSP) for patients with total colonic aganglionosis (TCA), including some patients who underwent surgical treatment after the age of 1 year.

METHODS

A retrospective, comparative study of TCA patients who underwent SLSP or PLSP at Beijing Children Hospital from 2007 to 2017 was conducted. The primary outcomes were height-for-age (HFA), weight-for-age (WFA), and bowel function score (BFS); the major types of postoperative complications were also analyzed.

RESULTS

Thirty-five patients (SLSP = 14, PLSP = 21) were included. The patients in the SLSP group underwent an enterostomy at a median age of 47 (14, 104) days. The median age at the time of the Soave procedure showed no significant difference between the two groups ([181 (131,346) vs 55 (29, 343)] days, p = 0.072). No significant differences between groups were noted in terms of presenting symptoms, perioperative results, and postoperative outcomes. Twenty-three patients (SLSP = 8, PLSP = 15) were followed for more than 1 year. Both the SLSP and PLSP groups showed similar operative mortality ([1/14, 7.1%] vs [3/21, 14.3%], p = 0.635) and complication rates ([postoperative enterocolitis, (5/8, 62.5%) vs (5/15, 33.3%), p = 0.221] [perianal excoriation, (7/8, 87.5%) vs (10/15, 66.6%), p = 0.369]). Nineteen patients (19/23, 82.6%) had normal growth according to the median percentage of HFA or WFA. Mean BFS was 15.9 ± 3.3 in the 15 patients aged older than 4 years who were followed up. Six patients (SLSP = 1, PLSP = 5) who underwent surgical treatment aged older than 1 year were all alive with good outcomes.

CONCLUSION

PLSP and SLSP had equivalent clinical outcomes, but enterocolitis and perianal excoriation after the Soave procedure need to be managed carefully. PLSP is a feasible option for older TCA patients after conservative treatment.

Visualization of the human enteric nervous system by confocal laser endomicroscopy in Hirschsprung's disease: An alternative to intraoperative histopathological diagnosis?

BACKGROUND

Hirschsprung's disease is a congenital abnormality of the enteric nervous system (ENS) presenting severe constipation soon after birth due to the lack of ganglion cells in the distal gut. Surgery for Hirschsprung's disease requires an intraoperative histopathological diagnosis to assess the extent of aganglionosis. Confocal laser endomicroscopy (CLE) is a novel endoscopic technique allowing real-time, in vivo analysis of cellular details during ongoing endoscopy. In this study, we evaluated the possibility of a new application of CLE to provide real-time observations of the ENS in patients with Hirschsprung's disease. In this preclinical feasibility study, we assessed the visualization of the ENS by CLE using surgically resected intestines.

METHODS

The subjects were nine patients who underwent pull-through surgery for Hirschsprung's disease between September 2014 and March 2016. The colon specimens were stained with 0.1% cresyl violet and evaluated using CLE. We compared the CLE findings with those of the histopathological examination.

KEY RESULTS

The ENS was clearly visualized as a ladder-like structure in the ganglionic segment but was not observed in the aganglionic segment. Of the 69 samples, corresponding positive and negative results for both CLE and the histopathology were obtained in 61 (88%). In addition, CLE was able to visualize unique, wavy structures comprising thick nerve bundles characteristic of the aganglionic/transition zone in Hirschsprung's disease.

CONCLUSIONS AND INFERENCES

As a novel tool for visualizing the human ENS, CLE has the potential to revolutionize how pediatric surgeons identify the level of ganglionosis during surgery for Hirschsprung's disease and may be a superior alternative to intraoperative histopathological diagnosis.

Transition Zone in Total Colonic Aganglionosis and Colorectal Hirschsprung's Disease Shows a Similar Trend of Mucosal Innervation: Image Processing and Analysis Study

The aganglionic segment of bowel in Hirschsprung's disease (HD) varies in length. It is not clear whether total colonic aganglionosis (TCA) merely represents a long form of HD or a different phenotype of the disease. Animal model studies suggest that TCA may have a longer transition zone (TZ) than conventional colorectal HD. We compared mucosal innervation of TZ in 2 TCA cases and 10 conventional colorectal HD cases by quantifying calretinin-positive mucosal nerve fibers using image processing and analysis. One TCA was associated with esophageal atresia-tracheoesophageal fistula, the other with trisomy 21. The gradients of calretinin-stained pixel count increase per distance from the beginning of TZ (slope) for TCA were not significantly different from those for the conventional HD group. Given this observation, it is speculated that the length of TZ in TCA may fall within the range of and may not be much longer than conventional colorectal HD.

Are We Underdiagnosing Hirschsprung Disease?

Hirschsprung disease (HSCR) is conventionally defined as aganglionosis of the distal rectum and a variable length of proximal contiguous bowel with a transition zone of ganglionic, but neuroanatomically abnormal, bowel located immediately upstream. Recent improvement in our understanding of the pathology and genetics of HSCR and relevant animal models indicates highly variable expressivity. The spectrum of intestinal neuropathology includes patients with very short-segment aganglionosis, limited to the distal 1 to 2 cm of the rectum, and possibly patients with no true aganglionic segment, but nonphysiological transition zone pathology in their distal rectums. The presence or absence of submucosal ganglion cells in a rectal biopsy is not sufficient to exclude these patients, in whom submucosal nerve hypertrophy and/or abnormal cholinergic mucosal innervation may be the only diagnostic clues. In addition, diagnosis or exclusion of HSCR by rectal biopsy now relies in part on mucosal patterns of calretinin immunohistochemistry, with less emphasis on submucosal tissue adequacy and assessment of cholinergic innervation. These recent trends in the surgical pathology approach to rectal biopsies may miss patients at the phenotypically milder end of the malformation spectrum, with profound implications for subsequent management, prognosis, and genetic counseling.

Variability of the transition zone length in Hirschsprung disease

BACKGROUND

Surgical management of Hirschsprung disease (HD) involves fully excising the transition zone (TZ). The literature suggests that resection of ≥5 cm of ganglionic bowel proximal to the aganglionic segment is sufficient. Our primary aim was to evaluate the lengths of the TZ in a cohort of consecutive patients with HD. We reviewed the impact this had on the need for revision surgery. We hypothesized that the TZ can be highly variable and may lead to a TZ pull-through when the proximal donut is not reviewed intraoperatively.

METHODS

A retrospective review was conducted for all patients undergoing primary pull-through surgery between January 2012 and September 2018. Data was collected on demographics, need for staged surgery, and complications following surgery.

RESULTS

Forty-eight patients were eligible for inclusion. 11/48 (23%) patients presented late (>6 months). 27/48 (56%) patients needed a stoma prior to definitive surgery. The median age at pull-through was 6 months (1-84 months). The median TZ length was 1.7 cm (0.3-22.9 cm). 11/48 (23%) had a TZ >5 cm. 36/48 (75%) patients did not have intraoperative review of the donut resulting in three TZ pull-throughs.

CONCLUSIONS

We would advocate circumferential intraoperative frozen section review of the proximal donut to minimize the risk of a TZ pull-through.

LEVEL OF EVIDENCE

Level III.

Surgery, Surgical Pathology, and Postoperative Management of Patients With Hirschsprung Disease

Endorectal pullthrough surgery is integral in the treatment of patients with Hirschsprung disease. Several different surgical procedures exist, which share as common goals to excise the aganglionic segment and upstream transition zone and attach ganglionic bowel just proximal to the anal canal. The operation requires collaboration between surgeon and pathologist to localize ganglionic bowel and prevent retention of transition zone. Intraoperative frozen sections are extremely important, first to establish that ganglion cells are present and subsequently to exclude features of transition zone (partial circumferential aganglionosis, myenteric hypoganglionosis, and submucosal nerve hypertrophy) at the proximal surgical (anastomotic) margin. Postoperative histopathological analysis of resection specimens should be tailored to document distal aganglionosis, document the length of the aganglionic segment and its proximity to the anastomotic margin, and confirm that transition zone has been resected completely. Adherence to the recommendations described in this review will reduce the likelihood of transition zone pullthrough and should decrease the incidence of persistent postoperative obstructive symptoms.

Usefulness of Delayed Films of Contrast Enema for Detecting Hirschsprung's Disease

Background

Contrast enema (CE) in Hirschsprung’s disease (HD) provides a road map to surgeons by ascertaining the transition zone (TZ) and helps in pre-surgical planning. In our institute, we use CE as the initial investigation for HD and carry on till the whole colon is fully distended, followed by a 24-hour abdominal film which is also a part of the international protocol. The main aim of this study was to evaluate the usefulness of this 24-hour delayed film in detecting HD, compare it with gold-standard biopsy results, and to evaluate other imaging features of contrast enema for diagnosis of HD in our tertiary-care hospital in Pakistan. 

Methods

This retrospective study was conducted at the Department of Radiology, Aga Khan University Hospital, Karachi. Records of pediatric patients referred for radiological evaluation of symptoms and signs suspicious of HD during the years 2007-2017 were reviewed. A delayed film was labeled positive if the contrast was not completely evacuated when the residual contrast was present till transverse colon and not beyond. Specificity and sensitivity along with positive and negative predictive values were calculated for each finding according to rectal biopsy, taken as the gold standard.

Results

In all, 82 patients met the inclusion criteria out of 111 cases, as they had both biopsy results and delayed 24-hour films. HD was confirmed using rectal biopsy in 56 (43 patients were males and 13 were females) of 82 cases. The most sensitive radiological finding was the transition zone with a sensitivity of 91.07%. The rectosigmoid index was the second most common finding on contrast enema with a sensitivity and specificity of 91.07% and 83.93%, respectively. In all, 59% patients had a positive delayed 24-hour film and were confirmed with having HD on biopsy. The sensitivity, specificity, and positive predictive value of delay in contrast evacuation after 24 hours in our study was 81.25%, 90.91%, and 97.50% respectively.

Conclusion

Contrast enema examinations along with the 24-hour delayed film with mid transverse colon cut-off are optimal for initially investigating HD in a developing nation, and our results show that it correlates well with biopsy. However, rectal biopsy still remains the gold standard for diagnosis. 

The Extent of the Transition Zone in Hirschsprung Disease

BACKGROUND

Retained transition zone is a leading cause of obstructive symptoms after pull-through operation in Hirschsprung's disease.

OBJECTIVE

We aimed to evaluate the extent of the histological transition zone in patients with Hirschsprung's disease.

DESIGN

We performed an observational study. DAB+ immunohistochemistry for Protein Gene Product 9.5 was used to evaluate the neuronal networks in serial sections of pull-through specimens obtained from children with Hirschsprung's disease (n = 12). Reference ranges for ganglion size/density and nerve trunk diameter were statistically determined using healthy controls obtained from colostomy specimens from children with anorectal malformations (n = 8). The transition zone was defined as ganglionic bowel exhibiting ganglion hypoplasia, hypertrophic nerve trunks, or partial circumference aganglionosis.

RESULTS

The mean submucosal nerve trunk diameter in controls was 19.56 μm +/- 3.87 μm. The median age at pull-through for Hirschsprung's disease was 5 months (3-14 months). The median length of the transition zone across the population was 8 cm (4-22 cm). Median transition zone extent was significantly longer in patients with long-segment aganglionosis (n = 6) compared to rectosigmoid aganglionosis (n = 6, 13 cm vs 6 cm, p = 0.041). Due to the age of the patients enrolled, long-term follow-up of bowel function is not yet available.

CONCLUSION

Our data suggest that, in children with rectosigmoid Hirschsprung's disease, the transition zone can extend for up to 13 cm. In children with long-segment disease, a longer transition zone is possible. Extended resection at a minimum 5 cm beyond the most distal ganglionic intra-operative biopsy and intra-operative histological examination of the proximal resection margin are required to minimize transition zone pull-through.

LEVEL OF EVIDENCE

2.

Guidelines for synoptic reporting of surgery and pathology in Hirschsprung disease

BACKGROUND/PURPOSE

Synoptic, or standardized, reporting of surgery and pathology reports has been widely adopted in surgical oncology. Patients with Hirschsprung disease may experience morbidity related to surgical factors or underlying pathology and often undergo multiple operations. Our aim is to improve the postoperative outcome and care of patients with Hirschsprung disease by proposing a standardized set of data that should be included in every surgery and pathology report.

METHODS

Members of the American Pediatric Surgical Association Hirschsprung Disease Interest Group and experts in pediatric pathology of Hirschsprung disease participated in group discussions, performed literature review and arrived at expert consensus guidelines for surgery and pathology reporting.

RESULTS

The importance of accurate operative and pathologic reports and the implications of inadequate documentation in patients with Hirschsprung disease are discussed and guidelines for standardizing these reports are provided.

CONCLUSIONS

Adherence to the principles of reporting for operations and surgical pathology may improve outcomes for Hirschsprung disease patients and will facilitate identification of correlations among morphology, function, genetics and outcomes, which are required to improve the overall management of these patients.

LEVEL OF EVIDENCE

V.

Unexpected gap between intraoperative caliber change of the intestine and normoganglia in patients with intestinal aganglionosis

PURPOSE

Intestinal aganglionosis (IA) is so rare that the entity remains unclear. The aim of the present study was to compare the outcomes of patients with IA and those with total colonic aganglionosis (TCA).

METHODS

The hospital records were retrospectively reviewed from 1977 to 2018. Outcomes were analyzed for the IA group and the TCA group, including clinical presentation, initial management, and operative details.

RESULTS

There were six patients were managed in IA (all male) and seven patients in TCA (4 male). The median age at the first operation was significantly younger in IA than TCA (2 days vs 24 days, p = 0.01). The gap between the intraoperative caliber change (CC) of the intestine and the initial stoma location was not significantly different (7.5 cm vs 12 cm, p = 0.61), but the rate of stoma dysfunction was significantly higher in IA (83% vs 0%, p = 0.005). The gap between the CC and the ganglionated bowel was significantly longer in IA (85 cm vs 10 cm, p = 0.003).

CONCLUSION

Patients with IA appear to have a high risk for stoma dysfunction after the first operation because of the unexpected gap between the CC and normoganglia. The initial location of the stoma requires careful consideration.

Remodeling of Rectal Innervation After Pullthrough Surgery for Hirschsprung Disease: Relevance to Criteria for the Determination of Retained Transition Zone

BACKGROUND

After pullthrough surgery for Hirschsprung disease (HSCR), Glut1-positive submucosal nerve hypertrophy is used to diagnose retained transition zone in the neorectum. We hypothesized that pelvic nerves, severed during pullthrough surgery, sprout into the neorectum to mimic transition zone.

METHODS

The density (nerves/100x field) and maximum diameter of Glut1-positive submucosal nerves were measured in biopsies and redo resections from 20 patients with post-pullthrough obstructive symptoms. Their original and/or redo resections excluded unequivocal features of transition zone (myenteric hypoganglionosis or partial circumferential aganglionosis) in 17. Postoperative values were compared with control data from 28 cadaveric and 6 surgical non-HSCR specimens, and 14 primary HSCR resections. When possible, nerves were tracked from attached native pelvic soft tissue or aganglionic rectal cuff into the pulled-through colon.

RESULTS

Glut1-positive submucosal nerves were not present in the 11 colons of non-HSCR infants less than 1 year of age, except sparsely in the rectum. In 17 older non-HSCR controls, occasional Glut1-positive nerves were observed in prerectal colon and were larger and more numerous in the rectum. In redo resections, Glut1-positive submucosal innervation in post-pullthrough specimens did not differ significantly from age-appropriate non-HSCR rectal controls and pelvic Glut1-positive nerves were never observed to penetrate the pulled-through colon. However, the density and caliber of Glut1-positive nerves in the neorectums were significantly greater than expected based on the prerectal location from which the pulled-through bowel originated.

CONCLUSIONS

Submucosal innervation in post-pullthrough specimens does not support the hypothesis that native pelvic nerves innervate the neorectum, but suggests remodeling occurs to establish the age-appropriate density and caliber of rectal Glut1-positive innervation. The latter should not be interpreted as transition zone pullthrough in a rectal biopsy from a previously done pullthrough.

Error traps and culture of safety in Hirschsprung disease

Hirschsprung disease affects many children every year around the world. Currently, there is an extensive menu of diagnostic methods, and surgical treatments. This situation compels the physicians to follow the rationale of these interventions. The comprehensive diagnosis and treatment of Hirschsprung disease need singular procedures. The clear understanding of how to perform each of these techniques, as well as to read the results is mandatory. Otherwise, the medical team may perform unconscious errors and fall into traps. Many errors still happen in patients with Hirschsprung, resulting in a spectrum of problems; from delayed diagnosis to unnecessary colectomies. In other patients, the damage to the anal canal results in fecal incontinence. When this is established, it is an unreversed and devastating social problem. This article describes why these errors occur and how to prevent them.

Laparoscopic Redo Pull-Through for Hirschsprung Disease Due to Innervation Disorders

BACKGROUND

Reoperations in Hirschsprung disease (HD) may be required due to pathological problems. We conducted this retrospective study to determine the incidence and outcomes of innervation disorders among HD patients following pull-through operation.

MATERIALS AND METHODS

We retrospectively reviewed the data of patients who underwent pull-through procedure from 2005 to 2017. Only patients who underwent reoperation due to histological disorders were analyzed. Patients with mechanical obstruction that caused recurrent constipation were excluded.

RESULTS

There were 836 patients who got treated for HD in our department during the study period, and of these, 72 (8.6%) had redo operation. Thirty-one out of the 72 patients (43.1%) showed abnormal histological findings on full-thickness biopsies. Primary operations included totally transanal endorectal pull-through (18), laparoscopic-assisted Duhamel (5) and Soave (8) techniques. The full-thickness biopsies before the reoperation showed aganglionosis (n = 8, 1 was residual resulted from false-positive intraoperative frozen sections and 7 were acquired aganglionosis), transition-zone (3), intestinal neuronal dysplasia B (IND B, n = 15), and hypoganglionosis (5). The final diagnoses according to the resection specimens of the initial and second operations were HD (11), Hirschsprung-associated IND B (15), and Hirschsprung-associated hypoganglionosis (5). Reoperation consisted of laparoscopic-assisted Duhamel (14) and Soave procedures (17). In these patients, 77.4% had excellent/good bowel function, 16.1% were fair, and 6.5% were poor.

CONCLUSIONS

Innervation disorders are still the underlying causes of recurrent constipation in almost half of all HD patients requiring redo pull-through operation. Most patients have a satisfactory outcome after redoing laparoscopic-assisted Duhamel or Soave operation.

Colonic Adventitial Fibromuscular Dysplasia: A Nonspecific Arteriopathy Associated With Hirschsprung Disease and Other Obstructive Disorders

Background Smooth muscle differentiation ("adventitial fibromuscular dysplasia," AFD) was purported as specific to arteries in the transition zone of Hirschsprung disease (HSCR) patients. We investigated AFD in an HSCR population and controls and consider the pathogenesis and significance of the vascular pathology. Design Vascular histology in sections from colonic HSCR resections (n = 55) was compared with age- and site-matched controls with (n = 19) and without (n = 28) non-HSCR obstructive conditions. Vascular pathology was mapped, and correlations were sought between the vascular findings and bowel distension, inflammation, neuromuscular anatomy, preoperative clinical variables, and postsurgical complications. Results One of 2 forms of AFD was identified in 42% (23/55) of the HSCR resections: the previously described "mature" form with adventitial bundles of differentiated smooth muscle cells (7/23, all submucosal) and a newly described "immature" AFD characterized by densely packed myofibroblasts in the arterial adventitia (16/23, 3 submucosal, 3 serosal, and 10 both). Adventitial inflammation and/or medial necrosis was present in the immature form (6/16). Mature submucosal AFD was present in 2/28 (7.1%) nonobstructive and 5/19 (26%) obstructive non-HSCR controls ( P = .10). Immature AFD was only found in less than 1-month-olds, and mature AFD only in older patients, including the 7 affected controls. AFD did not correlate with sex, syndromic status, length of the aganglionic segment, or postoperative complications. AFD was present in grossly dilated (17/23) and narrowed (10/23) regions and in the aganglionic (2/23), ganglionic (14/23), or both (7/23) segments. In several cases, AFD existed proximal to the histological transition zone. Conclusion AFD occurs in HSCR and other obstructive conditions but is significantly less common in the colons of patients with no history of dysmotility. The pathology likely progresses from a reversible accumulation of myofibroblasts in neonates to a stable population of mature smooth muscle cells. The distribution of vascular lesions does not correlate with neuropathological findings and suggests a nonspecific form of vascular injury, possibly related to bowel distension. AFD in HSCR resections has not been shown to be clinically significant and should not influence management.

Waardenburg syndrome with isolated deficiency of myenteric ganglion cells at the sigmoid colon and rectum

Waardenburg syndrome (WS) has the characteristic clinical features caused by the embryologic abnormality of neural crest cells. WS patients sometimes suffer from functional intestinal obstruction. When it is Hirschsprung disease (HD), the WS is diagnosed as type 4 WS. We report a case of WS which did not have myenteric ganglion cells in the sigmoid colon and rectum. Whether to diagnosis this case as type 1 or 4 WS is controversial. Moreover, this is the third report which has peristalsis failure caused by abnormal myenteric plexus. In all three cases, the eosinophils had aggregated in the myenteric layer of the transition zone. During embryonic life, enteric ganglion cells migrate to the myenteric layer from the proximal to the distal side sequentially and, subsequently, to the submucosal layer through the circular muscle. Therefore, we hypothesize that myenteric ganglion cells that had already migrated were eliminated by an eosinophil-mediated mechanism in these three cases. We believe this report may be helpful to elucidate the pathogenesis of some types of HD.

Hirschsprung Disease - Current Diagnosis and Management

Hirschsprung disease is a common cause of neonatal and infantile large gut obstruction. It is characterised by varying extent of contiguous aganglionosis extending from the anorectum proximally. Since its recognition, the diagnosis and management has continuously evolved with advances in histological evaluation and surgical techniques. This article summarizes the current modalities of investigation and optimal surgical management of Hirschsprung disease and concludes with a reference to the Indian scenario.

Choline Transporter Immunohistochemistry: An Effective Substitute for Acetylcholinesterase Histochemistry to Diagnose Hirschsprung Disease With Formalin-fixed Paraffin-embedded Rectal Biopsies

Acetylcholinesterase enzymatic histochemistry (AChE EHC), which highlights abnormal cholinergic nerves in the mucosa of aganglionic bowel, has been used for decades to evaluate rectal biopsies for Hirschsprung disease (HSCR). While useful diagnostically, AChE EHC is not compatible with conventional formalin-fixed and paraffin-embedded (FFPE) tissues and is not widely available. The choline transporter (ChT) is a putative alternative marker of cholinergic nerves. ChT immunohistochemistry (IHC) was investigated using FFPE biopsies and resections from patients with confirmed HSCR, as well as appropriate non-HSCR controls. ChT immunostaining was effective at identifying cases with HSCR and qualitatively similar to AChE EHC on frozen section. Among 3 pathologists, the diagnostic positive and negative predictive values based on ChT IHC ranged from 0.84-0.94 and 0.85-0.89, respectively, with good inter-observer agreement (Cohen kappa = 0.70-0.90). ChT IHC was useful in unusual scenarios in which calretinin (CR) IHC failed to correctly identify patients with HSCR. In 10 cases of short-segment HSCR, abnormal ChT+ mucosal innervation was present through the entire aganglionic segment and into portions of the TZ with submucosal nerve hypertrophy. In contrast, mucosal CR IHC was retained in the TZ and adjacent aganglionic bowel, which could lead to misinterpretation of a biopsy as ganglionic bowel. Indeed, 6 such patients were identified with paradoxical CR-positive mucosal innervation in their diagnostic biopsies. ChT IHC was interpreted as unequivocal HSCR in these cases, and HSCR was confirmed on resection. In summary, ChT IHC in FFPE tissue demonstrates high positive and negative predictive values for HSCR, is superior to CR IHC in a subset of cases, and can be incorporated into routine practice without the need for specialized techniques.

The utility of the hematoxylin and eosin staining in patients with suspected Hirschsprung disease

Background

While immunohistochemistry (IHC) methods have been widely conducted for the diagnosis of Hirschsprung disease (HSCR) in developed countries, there are very few studies on their use in developing countries where hematoxylin and eosin (HE) staining is a key element of the diagnosis of HSCR. We aimed to determine the accuracy of HE staining in the diagnosis of HSCR using S100 IHC as the reference standard in Indonesia.

Methods

All histopathology performed for the suspicion of HSCR patients from January 2013 to August 2015 in Dr. Sardjito Hospital, Yogyakarta, Indonesia, were retrospectively reviewed.

Results

Our study included 23 HSCR patients: 9 males and 14 females. The HE staining revealed 14 negative (absence of ganglion cells) cases (61%) and 9 positive (presence of ganglion cells) cases (39%). In S100 IHC, out of the 9 positive cases by HE staining, 6 (67%) were confirmed for having ganglion cells; and out of the 14 negative cases by HE staining, 12 (86%) were reported negative and 2 (14%) were positive by S100 IHC staining. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rates of the HE staining were 80% (95% CI: 0.51–0.95), 75% (95% CI: 0.36–0.96), 85.7% (95% CI: 0.56–0.98), 66.7% (95% CI: 0.31–0.91), and 78.3% (95% CI: 0.58–0.90), respectively.

Conclusions

Our study showed that HE staining has relatively moderate accuracy for the diagnosis of HSCR. The use of HE staining is still recommended for the diagnosis of HSCR given the limitation of resource allocation for more expensive IHC technologies in developing countries.

Pediatric enteric neuropathies: diagnosis and current management

PURPOSE OF REVIEW

Neurointestinal diseases are increasingly recognized as causes of significant gastrointestinal morbidity in children. This review highlights the most common pediatric enteric neuropathies and their diagnosis and management, emphasizing insights and discoveries from the most recent literature available.

RECENT FINDINGS

The embryologic and histopathologic causes of enteric neuropathies are varied. They range from congenital aganglionosis in Hirschsprung disease, to autoimmune-mediated loss of neuronal subtypes in esophageal achalasia and Chagas disease, to degenerative neuropathies in some cases of chronic intestinal pseudo-obstruction and gastroparesis. Increased awareness of the clinical presentation and diagnostic evaluation of these conditions is essential as it allows for earlier initiation of treatment and improved outcomes. Most current therapies, which include medical management, neurostimulation, and operative intervention, aim to minimize the symptoms caused by these conditions. The evidence base for many of these treatments in children is poor, and multiinstitutional prospective studies are needed. An innovative therapy on the horizon involves using neuronal stem cell transplantation to treat the underlying disorder by replacing the missing or damaged neurons in these diseases.

SUMMARY

Although recent advances in basic and clinical neurogastroenterology have significantly improved our awareness and understanding of enteric neuropathies, the efficacy of current treatment approaches is limited. The development of novel therapies, including pharmacologic modulators of neurointestinal function, neurostimulation to enhance gut motility, and neuronal cell-based therapies, is essential to improve the long-term outcomes in children with these disorders.

Guidelines for the management of postoperative obstructive symptoms in children with Hirschsprung disease

Although most children with Hirschsprung disease ultimately do well, many experience a variety of ongoing problems after pull-through surgery. The most common include obstructive symptoms, soiling, enterocolitis and failure to thrive. The purpose of this guideline is to present a rational approach to the management of postoperative obstructive symptoms in children with Hirschsprung disease. The American Pediatric Surgical Association Board of Governors established a Hirschsprung Disease Interest Group. Group discussions, literature review and expert consensus were then used to summarize the current state of knowledge regarding causes, methods of diagnosis, and treatment approaches to children with obstructive symptoms following pull-through for Hirschsprung disease. Causes of obstructive symptoms post-pull-through include mechanical obstruction; persistent or acquired aganglionosis, hypoganglionosis, or transition zone pull-through; internal sphincter achalasia; disordered motility in the proximal intestine that contains ganglion cells; or functional megacolon caused by stool-holding behavior. An algorithm for the diagnosis and management of obstructive symptoms after a pull-through for Hirschsprung disease is presented. A stepwise, logical approach to the diagnosis and management of patients experiencing obstructive symptoms following pull-through for Hirschsprung disease can facilitate treatment. Level of evidence V.