Reoperation for Hirschsprung disease: pathology of the resected problematic distal pull-through

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.

Postoperative Hirschsprung's associated enterocolitis (HAEC): transition zone as putative histopathological predictive factor

AIMS

Hirschsprung's-associated enterocolitis (HAEC) is the most severe complication of Hirschsprung disease (HD), and its pathogenesis is still unknown. Length of transition zone (TZ) interposed between aganglionic and normal bowel has been poorly explored as predictor for postoperative HAEC (post-HAEC). This study aimed to identify potential predictive factors for post-HAEC, with a particular focus on histopathological findings.

METHODS

Data from Hirschsprung patients treated in a single Italian centre between 2010 and 2022 with a follow-up >6 months were collected. Thorough histopathological examination of the resected bowel was conducted, focusing on length of TZ and aganglionic bowel.The degree of inflammatory changes in ganglionic resected bowel was further obtained. Ultra-long HD, total colonic aganglionosis and ultra-short HD were excluded. Bivariate and multivariate regression analysis were performed.

RESULTS

Thirty-one patients were included; 5 experienced preoperative HAEC (pre-HAEC) and later post-HAEC (16.1%), further 10 patients developed post-HAEC (total post-HAEC 48.38%). Pre-HAEC-history and a TZ<2.25 cm correlated with an early development of post-HAEC. Multivariate analysis identified a TZ<2.25 cm as an independent post-HAEC predictive factor (p=0.0096). Inflammation within the ganglionic zone and a TZ<2.25 cm correlated with higher risk of post-HAEC (p=0.0074, 0.001, respectively). Severe post-HAEC more frequently occurred in patients with pre-HAEC (p=0.011), histological inflammation (p=0.0009) and short TZ (p=0.0015).

CONCLUSIONS

This study suggests that TZ<2.25 cm predicts the risk of post-HAEC. Preoperative clinical and histopathology inflammation may predispose to worst post-HAEC. Readily available histopathological findings might help identifying patients at higher risk for HAEC and implementing prevention strategies.

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.

Evaluation and Management of Postsurgical Patient With Hirschsprung Disease Neurogastroenterology & Motility Committee: Position Paper of North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN)

Children with Hirschsprung disease have postoperative long-term sequelae in defecation that contribute to morbidity and mortality and significantly impact their quality of life. Pediatric patients experience ongoing long-term defecation concerns, which can include fecal incontinence (FI) and postoperative obstructive symptoms, such as constipation and Hirschsprung-associated enterocolitis. The American Pediatric Surgical Association has developed guidelines for management of these postoperative obstructive symptoms and FI. However, the evaluation and management of patients with postoperative defecation problems varies among different pediatric gastroenterology centers. This position paper from the Neurogastroenterology & Motility Committee of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition reviews the current evidence and provides suggestions for the evaluation and management of postoperative patients with Hirschsprung disease who present with persistent defecation problems.

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.

Reoperation for Hirschsprung Disease: Two cases of Vanishing Ganglion Cells and Review of the Literature

Hirschsprung disease (HD) is characterized by circumferential aganglionosis of the rectum with variable proximal bowel involvement. The underlying pathogenesis is due to failure of caudal migration of neural crest cells during pre-natal development, causing functional bowel obstruction. Definitive therapy is surgical resection; however, a subset of patients will require reoperation. An important cause of reoperation is the rare but distinct entity described as the ganglion cell "vanishing" phenomenon. In this phenomenon, affected patients have normal circumferential ganglion cells present at the proximal margin during primary resection. They undergo a variable asymptomatic period post-primary resection but ultimately develop recurrent symptoms. Upon reoperation, ganglion cells seemingly vanish and are no longer present in the previously functioning and ganglionated bowel proximal to the initial anastomotic site. To further characterize and investigate this poorly understood pathology, here we present 2 cases of HD patients who required reoperation. Our small series implicates that an immune component may contribute as patient 2 had a brisk neurotrophic eosinophilic infiltrate only present in the reoperation specimen. However, this was not observed in patient 1. Other possible etiologies include post-operative ischemia/hypoxia, visceral neuropathy, or signaling abnormalities within the residual ganglion cells themselves.

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.

Submucosal Nerve Diameter in the Rectum Increases With Age: An Important Consideration for the Diagnosis of Hirschsprung Disease

INTRODUCTION

Hypertrophic submucosal nerves, defined as ≥40 µm in diameter, are considered supportive of a diagnosis of HSCR, but the effect of age on nerve diameter has not been well-studied. We sought to determine the distribution of the largest nerve diameter in ganglionic rectal biopsies and the significance of hypertrophic submucosal nerves in the diagnosis of Hirschsprung disease (HSCR) based on age.

METHODS

Rectal biopsies performed in the evaluation of HSCR were retrospectively reviewed from 179 patients (151 ganglionic biopsies, 28 aganglionic biopsies), and the diameter of the largest submucosal nerve was measured.

RESULTS

In non-Hirschsprung disease (non-HSCR) biopsies, submucosal nerve diameter increased with age. In patients <1 year, the average diameter was 34.1 ± 11.6 µm but increased to 50.8 ± 17.3 µm after 1 year of age. Submucosal nerves ≥40 µm in diameter were significantly associated with HSCR across all ages [HSCR = 25/28 (89.3%) vs non-HSCR = 59/151 (39.1%), p < 0.0001] and remained significant in patients <1 year of age [HSCR = 22/24 (91.7%) vs non-HSCR = 19/91 (20.9%), p < 0.0001].

CONCLUSIONS

The diameter of submucosal nerves increases with age, and ≥40 µm nerves are common after 1 year of age.

Evaluation and treatment of the post pull-through Hirschsprung patient who is not doing well; Update for 2022

After operative intervention for Hirschsprung disease (HD) a child should thrive, be fecally continent, and avoid recurrent episodes of abdominal distention and enterocolitis. This is unfortunately not the case for a significant number of patients who struggle following their pull-through procedure. Many clinicians are puzzled by these outcomes as they can occur in patients who they believe have had a technically satisfactory described operation. This review presents an organized approach to the evaluation and treatment of the post HD pull-through patient who is not doing well. Patients with HD who have problems after their initial operation can have: (1) fecal incontinence, (2) obstructive symptoms, and (3) recurrent episodes of enterocolitis (a more severe subset of obstructive symptoms). After employing a systematic diagnostic approach, successful treatments can be implemented in almost every case. Patients may need medical management (behavioral interventions, dietary changes, laxatives, or mechanical emptying of the colon), a reoperation when a specific anatomic or pathologic cause is identified, or botulinum toxin when non-relaxing sphincters are the cause of the obstructive symptoms or recurrent enterocolitis.

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.

Evaluation and Management of Persistent Problems After Surgery for Hirschsprung Disease in a Child

PURPOSE OF REVIEW

Ideally, after operative intervention, a child born with Hirschsprung disease (HD) should thrive, achieve fecal continence, and avoid recurrent episodes of abdominal distention and enterocolitis. However, a significant number of patients continue to struggle following their pull-through procedure. The purpose of this review is to present an organized and practical approach to the evaluation and management of the symptomatic patient post pull-through operation for HD.

RECENT FINDINGS

Children diagnosed with HD who are not doing well after their initial operation can be categorized in three distinct groups: (1) those that have fecal incontinence, (2) those with obstructive symptoms, and (3) those with recurrent episodes of enterocolitis. It is important to have a systematic diagnostic approach for these patients based on a comprehensive protocol. All three of these patient groups can be treated with a combination of either medical management, reoperation when a specific anatomic or pathologic etiology is identified, or botulinum toxin for non-relaxing sphincters contributing to the obstructive symptoms or recurrent enterocolitis. For patients not doing well after their initial pull-through, a systematic workup should be employed to determine the etiology. Once identified, a multidisciplinary and organized approach to management of the symptomatic patients can alleviate most post pull-through symptoms.

Reoperative techniques and management in Hirschsprung disease: a narrative review

The majority of children who undergo operative management for Hirschsprung disease have favorable results. A subset of patients, however, have long-term dysfunctional stooling, characterized by either frequent soiling or obstructive symptoms. The evaluation and management of a child with poor function after pull-through for Hirschsprung disease should be conducted by an experienced multidisciplinary team. A systematic workup is focused on detecting pathologic and anatomic causes of pull-through dysfunction. This includes an exam under anesthesia, pathologic confirmation including a repeat biopsy, and a contrast enema, with additional studies depending on the suspected etiology. Obstructive symptoms may be due to technique-specific types of mechanical obstruction, histopathologic obstruction, or dysmotility-each of which may benefit from reoperative surgery. The causes of soiling symptoms include loss of the dentate line and damage to the anal sphincter, which generally do not benefit from revision of the pull-through, and pseudo-incontinence, which may reveal underlying obstruction. A thorough understanding of the types of complications associated with various pull-through techniques aids in the evaluation of a child with postoperative dysfunction. Treatment is specifically tailored to the patient, guided by the etiology of the patient's symptoms, with options ranging from bowel management to redo pull-through procedure. This review details the workup and management of patients with complications after pull-through, with a focus on the perioperative management and technical considerations for those who require reoperation.

Redo Transanal Soave Pull Through with or without Assistance in Hirschsprung Disease: An Experience in 46 Patients

INTRODUCTION

 Transanal Soave pull through (PT) with or without assistance can be performed as a redo procedure for Hirschsprung disease (HD). In this study, we reviewed the indications and clinical outcomes of redo transanal Soave with or without assistance.

MATERIALS AND METHODS

 A retrospective analysis was performed on patients who underwent redo transanal Soave with or without assistance in our hospital from 2004 to 2016, and did not have rectourethral fistula or rectovaginal fistula. The Krickenbeck classification system was used to evaluate postoperative bowel function. We analyzed the associated factors of the two main indications.

RESULTS

 In this study, 46 patients were included, representing 5.6% of all HD PTs; 42 patients were initially operated elsewhere and 4 at our hospital. Primary PT surgeries included 38 transanal Soave, 2 Rehbein, 1 Martin, and 5 unknown procedures. The indications for redo PT were residual aganglionosis/transition zone PT (RA/TZPT) (27, 58.7%), anastomotic complication (14, 30.4%), and dilated distal segment (5, 10.9%). The median age of these 46 patients at primary and redo PT was 7.0 months (range, 0.4-137 months) and 45.5 months (range, 7-172 months), respectively. All 46 patients underwent redo transanal Soave PT; 43 patients (93.5%) underwent transanal Soave with laparotomy (n = 42) or laparoscopy (n = 1), and another 3 patients underwent transanal Soave PT. Six patients (13%) experienced complications within 30 days after redo surgery. A total of 43 patients were followed up, and the median follow-up period was 100 months (range, 35-180 months). Two patients could not hold back defecation in some inconvenient conditions. Sixteen patients (37.2%) had soiling, and 8 (18.6%) of 16 patients complained frequent soiling occurrence (more than 1/week). Only one patient complained of constipation (grade 1). Patients with anastomotic complication had more early postoperative complication and higher rate of soiling than patients with RA/TZPT, but there was no statistical difference (p = 0.672 and p = 0.105).

CONCLUSION

 Transanal Soave PT with or without assistance was effective in resolving different problems after initial PT, while soiling was the most common postoperative problem, especially patients with anastomotic complication.

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.

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.

Functional outcome, quality of life, and 'failures' following pull-through surgery for hirschsprung's disease: A review of practice at a single-center

AIMS

The purpose of this study was to assess bowel function and quality of life (QoL) in patients with Hirschsprung's disease (HD) and identify patients who have 'failed' treatment.

METHODS

A review of a single-center HD cohort treated with pull-through surgery from 2004 to 2017 was completed. Bowel function of patients five years and above and QoL of all patients were assessed using validated questionnaires. Patients who 'failed' treatment were defined as above five years with one or more of: a) long-term stoma, b) needing an antegrade continence enema or transanal irrigation, c) severe soiling, or d) severe constipation. Statistical analysis was performed with P < 0.05 deemed significant. Data are given as mean [range].

RESULTS

Seventy-one patients presented with HD within the study period. Mean follow-up was 5.4 years [0.7-13.3]. Of 38 eligible patients, bowel function was assessed in 24 patients (nine had a stoma, five lost to follow-up). The mean incontinence score was 17 [0-28)], and the mean constipation score was 17 [5-25]. Incontinence and constipation scores were worse than healthy controls (P < 0.001 and P = 0.001, respectively) and did not improve with age. Fifty-six patients had QoL assessed with no difference between our cohort (81 [25-100]) and healthy controls (81 [unknown]); (P = 0.85). Thirty-three patients were assessed for 'failure' (bowel function score n = 24; stoma n = 9). Thirty of 33 (91%) children older than five years can be considered to have 'failed' treatment.

CONCLUSIONS

Patients have worse bowel function than healthy children, which does not improve with age. QoL is comparable to healthy controls. A significant proportion of patients have poor outcomes and have 'failed' treatment.

LEVEL OF EVIDENCE

Level III.

Postoperative Pullthrough Obstruction in Hirschsprung Disease: Etiologies and Diagnosis

Some patients continue to have obstructive symptoms and/or incontinence after pullthrough surgery for Hirschsprung disease. Incontinence can be due to injury to the anal sphincter and/or dentate line, abnormal colonic motility (nonretentive), or a chronic large stool burden (retentive). A diagnostic algorithm based on clinical and pathological evaluations can be applied to distinguish potential etiologies for obstructive symptoms, which segregate into anatomic (mechanical or histopathological) or physiologic subgroups. Valuable clinical information may be obtained by anorectal examination under anesthesia, radiographic studies, and anorectal or colonic manometry. In addition, histopathological review of a patient's original resection specimen(s) as well as postoperative biopsies of the neorectum usually are an important component of the diagnostic workup. Goals for the surgical pathologist are to exclude incomplete resection of the aganglionic segment or transition zone and to identify other neuromuscular pathology that might explain the patient's dysmotility. Diagnoses established from a combination of clinical and pathological data dramatically alter management strategies. In rare instances, reoperative pullthrough surgery is required, in which case the pathologist must be aware of histopathological features specific to redo pullthrough resection specimens.

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.

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.

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.

Development of Nerve Fibre Diameter in Young Infants With Hirschsprung Disease

OBJECTIVES

Finding thickened nerve fibres is one of the key elements in the diagnosis of Hirschsprung disease (HD); however, its value at different ages remains uncertain. Nerve fibre diameters <40 μm can be observed in infants younger than 8 weeks, despite the presence of HD. The aim of this study was to identify a change in maximum nerve fibre diameter in HD patients, measured before and after 8 weeks of age.

METHODS

Nerve fibre diameter was retrospectively evaluated in tissue of 20 infants treated for definite HD. Rectal suction biopsies (RSBs) obtained within the first 8 weeks of life (T1) and resected bowel obtained during primary surgery at an average of 24.7 weeks (T2), were assessed. The 2 thickest nerve fibre diameter recordings at T1 and T2 were compared in each subject, to examine changes in nerve trunk diameter with increasing age.

RESULTS

In 13 cases (65%), nerve fibre diameters were ≥40 μm at T1 and T2. Six subjects (30%) had nerve trunk diameters <40 μm at T1; however, they experienced diameter increases to ≥40 μm by T2. Thus, at T2, 19 subjects (95%) had diameter recordings ≥40 μm. Nerve fibre diameter in the remaining case (5%) stayed consistent at <40 μm at T1 and T2, despite the presence of HD.

CONCLUSIONS

After the first 8 weeks of life, nerve fibre measurements appear to be associated with HD. Measuring the 2 thickest nerve fibres can support typical HD diagnosis criteria beyond 8 weeks of age, but is not superior to histopathological confirmation of aganglionosis.

The anal canal is the fine line between "fecal incontinence and colitis" after a pull-through for Hirschsprung disease

BACKGROUND/PURPOSE

Fecal incontinence after a pull-through is associated with different factors, although damage to the anal canal seems to be the most important. The objective of this article is to identify the variables related to the presence of fecal control and colitis in a homogeneous group of children after pull-through.

METHODS

A retrospective cross-sectional study was performed in patients with HD for evaluation of post-operative problems from May 2014 to November 2016. The patients (39) had a transanal approach and were divided into two groups: Group 1 patients with fecal continence and Group 2 patients with fecal incontinence.

RESULTS

Group 1 patients (13) had the anastomosis in the rectum, no damage to the anal canal, and a positive history of colitis. Group 2 (26) had the anastomosis at the skin, anoderm, pectinate line, or a combination of these and a negative history of colitis.

CONCLUSIONS

We demonstrated that patients with a technical error in the anastomosis have fecal incontinence, but not colitis. Preservation of the anal canal is associated with fecal control and colitis because it is a high-pressure zone. Education for proper identification of the anal canal during a pull-through is an absolute necessity.

TYPE OF STUDY

Retrospective Comparative Study.

LEVEL OF EVIDENCE

Level III.

Rectal Suction Biopsy in Patients With Previous Anorectal Surgery for Hirschsprung Disease

OBJECTIVES

The aim of the study was to determine rates of histologically positive, negative, and inconclusive rectal suction biopsies in post-pull-through patients with Hirschsprung disease evaluated for potential residual aganglionosis at our institution and to determine how patients were managed after a post-pull-through rectal suction biopsy.

METHODS

Thirty-nine post-pull-through suction biopsies from our institution were reviewed. Samples, stained with H&E and often acetylcholinesterase and/or calretinin, were categorized as "histologically" positive, negative, or inconclusive for aganglionosis. Subsequent clinical action was categorized as bowel resection, no further procedure, or rebiopsy. Agreement between histologic diagnosis and clinical action was assessed.

RESULTS

Histologically, all biopsies were inconclusive (46%) or negative (54%) for residual aganglionosis. Postbiopsy clinical action included redo pull-through (5%), no further procedure (59%), or rebiopsy (36%). Rebiopsy was sought in 2 of 21 histologically negative patients and in only 12 of 18 histologically indeterminate patients. Eventual redo pull-through procedures in 6 of 39 patients showed 4 with residual aganglionosis and 2 with abnormalities suggesting residual "transition zone."

CONCLUSIONS

Our findings show that suction biopsy after pull-through was frequently histologically indeterminate and never definitively positive for residual aganglionosis. When biopsy was histologically indeterminate, rebiopsy was pursued less commonly than may be expected. Our findings emphasize that suction biopsy examination is not a "criterion standard" for residual aganglionosis, but instead a component of a diagnosis that ultimately combines clinicopathologic factors, the constellation of which can sometimes spare patients from a more invasive full-thickness biopsy.

Histology of the Transition Zone in Hirschsprung Disease

Surgical management of Hirschsprung disease requires resection of the aganglionic bowel and transition zone, a length of ganglionic bowel, immediately proximal to the aganglionic segment, with neuropathologic features that seem to correlate with dysmotility. Pathologists must be able to recognize histopathologic features of the transition zone in hematoxylin and eosin-stained sections in order to interpret intraoperative frozen sections and ensure adequate resection. The proximal ganglionic portions of colonic resection specimens from 59 patients with distal aganglionosis were analyzed with closely spaced transverse sections to map the distribution of the 3 most commonly referenced features of transition zone (partial circumferential aganglionosis, myenteric hypoganglionosis, and submucosal nerve hypertrophy). Each of these "primary" findings was restricted to a region ≤5 cm proximal to the aganglionic segment in the overwhelming majority of patients. Exceptions were more common with longer aganglionic segments. Three other neuroanatomic phenotypes (gangliosclerosis, ectopic myenteric ganglia, and eosinophilic ganglionitis) of uncertain clinical significance were distributed more irregularly and often over much longer distances. Routine resection of at least 5 cm of ganglionic bowel proximal to the aganglionic segment may reduce the incidence of transition zone pull-through. However, routine intraoperative frozen section examination of the proximal resection margin to exclude the 3 primary forms of hematoxylin and eosin neuropathology described in this study is strongly advised.

Redo pullthrough for Hirschsprung disease

Pullthrough procedures for Hirschsprung diseases typically have favorable results. However, some children experience long-term postoperative complications comprising stooling disorders, such as intermittent enterocolitis, severe stool retention, intestinal obstruction, as well as incontinence. Reoperative Hirschsprung Disease surgery is complex. This begins with the workup after the initial presentation following primary pullthrough, continues with the definitive surgical correction with redo pullthrough, and ends with long-term follow-up of individuals. The decision tree can be varied with each patient. The operating pediatric surgeon must be able to utilize different operations and treatment options available. While lesser procedures may provide relief in a select population, those with residual aganglionosis or transition zone pathology or mechanical problems will likely require a redo pullthrough. Thus, the diagnostic workup, treatment plan, and definitive surgical care should be coordinated, and executed by an experienced, specialized team at a pediatric referral center.

Usefulness of posterior sagittal anorectoplasty for redo pull-through in complicated and recurrent Hirschsprung disease: Experience with a single surgical group

AIM

To retrospectively examine 12 patients with Hirschsprung disease (HD) who underwent posterior sagittal anorectoplasty (PSARP) for various complications.

METHODS

This study included patients with HD who underwent redo pull-through (PT) via PSARP at our institute between 2005 and 2014. The type of initial procedure, clinical presentations, indications, and functional results were analyzed. Postoperative excretory function was assessed using the Krickenbeck classification.

RESULTS

The study group comprised 9 boys and 3 girls (total, 12). Five patients were diagnosed with rectosigmoid aganglionosis, 5 with long segment aganglionosis, and 2 with total colonic aganglionosis. The primary operations performed on these patients included the Soave, Duhamel, Swenson, Rehbein, and Ikeda-Soper procedures. The interval between the primary operations and reoperation ranged from 5months to 8years (median, 3years). The indications for PSARP were rectocutaneous fistulae (6 cases), frozen pelvis (5 cases), severe anastomotic stricture (3 cases), rectovaginal fistulae (2 cases), and hemorrhagic proctitis with an inflammatory polyp (1 case). All fistulae were repaired using PSARP; only one rectocutaneous fistula recurred and required two additional surgeries. Stricture and hemorrhagic proctitis were cured in all involved cases. Nine patients were followed up for 8months to 10years after PSARP surgery (average, 5.1years). All 9 patients had voluntary bowel movements within 6months after the last PSARP and stoma closure: 3 had normal bowel movement, while 6 had varying degrees of soiling, depending on the length of residual colon. None complained of constipation.

CONCLUSION

PSARP is useful for treating severe complications of failed PT in HD. Complex and recurrent rectocutaneous fistulae and frozen pelvis are the main indications for PSARP, while soiling is the most common surgical complication.

Pathological changes of interstitial cells of Cajal and ganglion cells in the segment of resected bowel in Hirschsprung's disease

OBJECTIVES

This study was conducted to investigate the pathological changes which occur in interstitial cells of Cajal (ICCs) and ganglion cells found in segments of resected bowel obtained from patients with Hirschsprung's disease (HD), as well as to explore the benefits of using a contrast enema (CE) with 24-h delayed X-ray films to predict the length of resected bowel.

METHODS

We performed a retrospective analysis of 58 children with HD who had undergone the pull-through procedure. After each operation, the ICCs and ganglion cells present in the proximal ends of the barium residue (Level A) and resected proximal bowel segment (Level B) were analyzed using immunohistochemical staining methods. Each patient was followed up for 1 year to record their stool frequency, defecation control ability, and post-surgical complications which may have occurred.

RESULTS

Immunohistochemical staining detected fewer ICCs in Level A than in Level B (p < 0.05). However, the density of ganglion cells in the two levels was not significantly different (p > 0.05). One patient had anastomotic stricture, and five patients suffered from enterocolitis.

CONCLUSIONS

The density of ICCs was significantly lower in the bowel segments that displayed barium retention. A CE may be a valuable tool for predicting the length of bowel resection in patients with HD.

Submucosal nerve diameter of greater than 40 μm is not a valid diagnostic index of transition zone pull-through

BACKGROUND

Submucosal nerve hypertrophy is a feature of the transition zone in Hirschsprung disease and has been used as a primary diagnostic feature of transition zone pull-through for patients with persistent obstructive symptoms after their initial surgery. Most published criteria for identification of hypertrophy rely on a nerve diameter of greater than 40μm, based primarily on data from a relatively small number of infants with Hirschsprung disease and controls. The validity of these objective measures has not been validated in appropriate controls for post-pull-through patients.

SCIENTIFIC APPROACH

The primary pull-through specimens and post pull-through biopsies +/- redo pull-through resections from a series of 9 patients with Hirschsprung disease were reviewed to assess the prevalence of submucosal nerves >40μm in diameter and 400× microscopic fields containing two or more such nerves. Similar data from multiple colonic locations were collected from a series of 40 non-Hirschsprung autopsy and surgical controls.

RESULTS

The overwhelming majority of Hirschsprung patients harbored submucosal nerves >40μm in their post-pull-through specimens independent of other features of transition zone pathology, and despite normal innervation at the proximal margins of their initial resections. Measurement of submucosal nerve diameters in autopsy and surgical non-Hirschsprung control samples indicated that nerves >40μm are normal in the distal rectum after 1year of age and are found in more proximal colon at older ages.

CONCLUSIONS

These results suggest that diagnostic criteria currently used to recognize submucosal nerve hypertrophy in the neorectum after a pull-through for Hirschsprung disease are not justified and should not be regarded as definitive evidence for transition zone pull-through.

Laparoscopy-assisted versus transabdominal reoperation in Hirschprung's disease for residual aganglionosis and transition zone pathology after transanal pull-through

INTRODUCTION

This study aims to describe laparoscopic reoperation (LSR) and compare its outcomes with transabdominal reoperation (TAR) for treating Hirschsprung's disease (HD).

PATIENTS AND METHODS

Eighteen patients with HD underwent reoperation for recurring constipation due to residual aganglionosis and transition zone pathology after an initial transanal procedure (LSR, n=10; TAR, n=8). Preoperative, operative and postoperative data were collected through patient follow-ups ranging from 13 to 75months to compare operative characteristics and postoperative outcomes between the two groups.

RESULTS

Ten patients underwent laparoscopic reoperation in our institution without major complications. On average, blood loss was significantly lower in the LSR group (mean±standard deviation, 83±32.7mL) than in the TAR group (185±69mL) (P=0.001). The LSR group had a shorter hospitalization time (12±2days) than the TAR group (15±2.1days) (P=0.02). There was no statistically significant difference in incidence of postoperative complications between the two groups.

CONCLUSIONS

LSR is safe and technically feasible in HD for recurring constipation due to residual aganglionosis and transition zone pathology, when initial transanal procedure fails. Although RA and TZP can be cured by reoperation, great efforts should be made to diminish the necessity of reoperation.

Calretinin-Immunoreactive Hypoinnervation in Down Syndrome (DS): Report of an Infant with Very Short-Segment Hirschsprung Disease and Comparison to Biopsy Findings in 20 Normal Infants and 11 Infants with DS and Chronic Constipation

In Down syndrome (DS) constipation is common, and the incidence of Hirschsprung disease (HD) is 1-2%. Rectal suction biopsies (RSBs) in DS may show discordant features; calretinin immunoreactivity (CRir) often helps resolve discrepancies. We report a case of unequivocal very short-segment HD (vsHD) in an infant with DS who had aganglionosis with abnormal acetylcholine esterase (AChE) activity in 3 RSBs. The CRir patterns were scanty positive rather than the expected absent CRir innervation in the lamina propria (LP). The resection specimen was grossly typical for short-segment HD, with a 5.5-cm, narrow but normally ganglionated segment proximal to the verified very short distal anganglionic zone. Unequivocal calretinin hypoinnervation was limited to the distal 2 cm, substantiating the warning of Kapur that small numbers of CRir nerves in the LP do not exclude a diagnosis of vsHD. We evaluated RSBs from 11 DS and 20 randomly selected normal infants <6 months of age with chronic constipation. The normal infants had abundant mucosal calretinin innervation and AChE histochemistry. We observed variable CRir hypoinnervation in RSBs in DS infants (including 6/7 with "normal" original diagnosis and 1/4 with HD). Our findings caution against overdependence on "normal" calretinin immunohistochemistry and suggest that AChE may be more reliable than CRir in the context of DS. An unknown number of patients with DS may have enteric nervous system disorders functionally similar to HD, which are possibly related to abnormal or imbalanced autonomic innervation, of which distal calretinin hypoinnervation is one manifestation, despite the presence of ganglia.

Intestinal Neuronal Dysplasia-Like Submucosal Ganglion Cell Hyperplasia at the Proximal Margins of Hirschsprung Disease Resections

Intestinal neuronal dysplasia type B (IND) denotes an increased proportion of hyperplastic submucosal ganglia, as resolved histochemically in 15-μm-thick frozen sections. IND has been reported proximal to the aganglionic segment in patients with Hirschsprung disease (HSCR) and is putatively associated with a higher rate of postsurgical dysmotility. We developed and validated histological criteria to diagnose IND-like submucosal ganglion cell hyperplasia (IND-SH) in paraffin sections and used the approach to study the incidence and clinical and/or genetic associations of IND-SH at the proximal margins of HSCR pull-through resection specimens. Full-circumference paraffin sections from the proximal margins of 64 HSCR colonic pull-through specimens and 24 autopsy controls were immunostained for neuron-specific Hu antigen, and nucleated ganglion cells in each submucosal ganglion were counted. In controls, an age-related decline in the relative abundance of "giant" ganglia (≥7 nucleated Hu-positive [Hu+] ganglion cells) was observed. A conservative diagnostic threshold for IND-SH (control mean ± 3× standard deviation) was derived from 15 controls less than 25 weeks of age. No control exceeded this threshold, whereas in the same age range, IND-SH was observed at the proximal margins in 15% (7 of 46) of HSCR resections, up to 15 cm proximal to the aganglionic segment. No significant correlation was observed between IND-SH and length of or distance from the aganglionic segment, sex, trisomy 21, RET or SEMA3C/D polymorphisms, or clinical outcome, but analysis of more patients, with better long-term follow-up will be required to clarify the significance of this histological phenotype.

Redo pullthrough for Hirschsprung disease: a single surgical group's experience

INTRODUCTION

This study presents our surgical experience for redo-pullthrough (RedoPT) for Hirschsprung disease (HD). It reviews the patient's clinical outcomes and assesses stooling patterns after RedoPT.

METHODS

A retrospective review of our institution's RedoPTs as well as one author's overseas cases was performed. Stooling scores were tabulated using an established survey tool and compared to primary PT matched patients.

RESULTS

Between 1974 and 2012, 46 individuals (52% males) underwent RedoPT, representing 3 percent of all HD pullthroughs. Median age at primary PT and RedoPT was 1year (range 1week-18years) and 3.5years (range 8weeks-41years), respectively. Indications for RedoPT were predominately for aganglionosis/transition zone pathology (71%); followed by stricture or an obstructing Duhamel pouch (19%), tight cuff (8%) and a twisted PT (4%). None were performed for an isolated clinical diagnosis of repeated bouts of enterocolitis. RedoPT surgical approach depended upon the initial pullthrough technique and any previous complications. Stooling scores were significantly (P<0.05) worse in the RedoPT patients compared to the historically-matched group of children undergoing a primary PT for HD (5.5±1.2 vs. 12.2±1.4, primary PT versus RedoPT, respectively). When breaking down this total score into individual parameters, stooling pattern scores (1.0±0.2 vs. 4.1±0.4, P=0.001) and enterocolitis scores (2.0±0.4 vs. 4.2±0.4, P=0.001) were statistically worse in the RedoPT group. Patients in both groups had similar overall continence rates.

CONCLUSION

Appropriately selected children undergoing a RedoPT can achieve good results, with comparable continence rates to those undergoing a primary PT.

Advances in minimally invasive surgery in pediatric patients

Surgery has changed dramatically over the last several decades. The emergence of MIS has allowed pediatric surgeons to manage critically ill neonates, children, and adolescents with improved outcomes in pain, postoperative course, cosmesis, and return to normal activity. Procedures that were once thought to be too difficult to attempt or even contraindicated in pediatric patients in many instances are now the standard of care. New and emerging techniques, such as single-incision laparoscopy, endoscopy-assisted surgery, robotic surgery, and techniques yet to be developed, all hold and reveal the potential for even further advancement in the management of these patients. The future of MIS in pediatrics is exciting; as long as our primary focus remains centered on developing techniques that limit morbidity and maximize positive outcomes for young patients and their families, the possibilities are both promising and infinite.

A rare case of multiple skip segment Hirschsprung's disease in the ileum and colon

As a rare form of Hirschsprung's disease, skip segment Hirschsprung's disease (SSHD) involves a "skip area" in normally ganglionated intestine, surrounded by aganglionosis. We report a case of multiple SSHD in the ileum and colon with total colonic aganglionosis. To our knowledge, this is the 27th case of SSHD, the third paper on multiple-segment SSHD, and the second patient with SSHD in the ileum to be reported in the English literature.

Calretinin, β-tubulin immunohistochemistry, and submucosal nerve trunks morphology in Hirschsprung disease: possible applications in clinical practice

OBJECTIVES

The aim of this study was to investigate calretinin and β-tubulin immunohistochemical expression together with submucosal nerve trunks morphology in differently innervated segments of Hirschsprung disease (HD) and total colonic aganglionosis (TCA).

METHODS

A total of 25 cases (22 HD, 3 TCA) and 18 controls were processed for calretinin and β-tubulin immunohistochemistry. Sections representative of distal aganglionic, transition, and proximal ganglionic segments were evaluated by a visual grading score; β-tubulin was evaluated also by image analysis. Submucosal nerve trunks hypertrophy and hyperplasia were measured by citomorphology. The length of proximal segment was correlated to postoperative bowel function.

RESULTS

Controls showed intense calretinin and β-tubulin staining. In HD and TCA, calretinin staining was related to the presence of ganglion cells: negative in distal, faint in transition, intense in proximal segment. β-Tubulin staining was weak in all of the segments of HD and negative in TCA. Hypertrophic and hyperplastic nerve trunks characterized aganglionic segment, and progressively decreasing nerve size was observed in transition and ganglionic segments. Transient postoperative constipation, soiling, or enterocolitis was present in 59% of patients with HD without clear relation to proximal segment length or presence of hypertrophic nerve trunks.

CONCLUSIONS

Calretinin is a reliable marker of the presence of ganglion cells, and, together with nerve hypertrophy, it helps to identify the transition zone. Length and nerve size of proximal segment in resected specimen did not affect the postsurgical intestinal function. Reduced β-tubulin expression along the entire colonic tract, included proximal ganglionic segments, may represent a potential impairing factor for the enteric neural transmission.

Recent developments in Hirschsprung's-associated enterocolitis

Hirschsprung's-associated enterocolitis (HAEC) continues to be a significant source of morbidity for patients with Hirschsprung's disease (HD). New clinical and histologic classification systems for HAEC will improve consistency between reports and increase the ability to compare outcomes. A complete understanding of disease pathogenesis is lacking, but evidence suggests that the intestinal microbiota may play a role in the development of HD and HAEC. The benefits of adjunctive therapies, such as anal dilations and botulinum toxin to reduce the incidence of HAEC following corrective endorectal pull-through, remain controversial. Finally, new clinical data have identified an association between HAEC and inflammatory bowel disease and will likely lead to further genetic studies to elucidate the connection between these two disease processes.

Histopathologic delineation of the transition zone in short-segment Hirschsprung disease

Failure to completely resect the transition zone (TZ) between aganglionic and neuroanatomically normal bowel ("TZ pull-through") is considered one reason for postoperative obstructive symptoms in Hirschsprung disease (HD). Despite years of study, the proximal boundary of the TZ remains nebulous, complicated by discordant, often subjective, histopathologic definitions. In order to objectively delineate the TZ, transverse sections at 1 cm intervals from the rectums of 9 non-HD autopsy subjects and resections from 15 infants with short-segment HD were immunostained with Hu (ganglion cell bodies) and glucose transporter 1 (Glut1) (perineurium of extrinsic nerves), and 6 putative features of TZ were examined: (1) aganglionosis of ≥1/8th circumference; (2) myenteric or submucosal hypoganglionosis; (3) hypertrophic submucosal nerves; (4) Glut1+ submucosal innervation; (5) submucosal hyperganglionosis; and (6) "ectopic" ganglia in lamina propria, muscularis propria, or serosa. In non-HD controls, Glut1+ submucosal innervation, hypertrophic nerves, partial circumferential aganglionosis, and hypoganglionosis were absent or restricted to the distal 2 cm. In contrast, all 6 neuropathologic features of TZ were identified proximal to the aganglionic segment in the majority of HD resections, but the length of the TZ ranged from 0 to 12 cm, depending on which neuropathologic feature was considered. Excluding submucosal hyperganglionosis and ectopic ganglia, the TZ was generally ≤5 cm. Many features of TZ cannot be excluded intraoperatively with a biopsy or a full-circumference frozen section. However, partial circumferential aganglionosis, severe myenteric hypoganglionosis, and hypertrophic submucosal nerves can, and probably should, be assessed in full-circumference frozen sections of the proximal resection margin, to reduce the likelihood of TZ pull-through.

Multiphoton microscopy to identify and characterize the transition zone in a mouse model of Hirschsprung disease

BACKGROUND

The distribution of ganglion cells in the transition zone of Hirschsprung Disease (HD) colons is extremely variable. Determining the resection margin based on intraoperative biopsies may be imprecise. Multiphoton microscopy (MPM) is a novel imaging technology with the ability to visualize tissues in real time. In this study, we evaluate the potential of MPM to quantify ganglion cells in a murine model of HD.

METHODS

After IACUC approval, formalin-fixed colons from 7 wild type (WT) and 6 Endothelin Receptor B gene (EdnrB) homozygous knockout (KO) mice with distal colonic aganglionosis were assessed by MPM for the presence of myenteric ganglion cells. MPM images were captured starting from the anus progressing proximally at 5mm intervals. Hematoxylin and eosin (H&E) stained biopsies of the imaged were correlated with MPM findings.

RESULTS

WT specimens showed normal myenteric plexus ganglia throughout the examined colon. In contrast, distal colons of EdnrB KO animals were devoid of ganglia up to 10mm from the anus. Ganglion cells were visible starting at 20-30 mm proximal to the anus. The density of ganglion cells seen by MPM and histology correlated well.

CONCLUSIONS

MPM can clearly identify the myenteric plexus ganglia in both WT and KO mouse colons. Comparison with the H&E-stained sections showed reproducible correlation. MPM-based real-time imaging of the myenteric plexus may become a useful intraoperative decision-making tool in the future.

Colorectal considerations in pediatric patients

Colorectal disease in pediatric patients includes a spectrum of diseases, many of which have a significant impact on quality of life and warrant long-term follow-up and treatment into adulthood. Although many diseases, such as inflammatory bowel disease and colon cancer, are managed similar to adults, other disease processes are more common to pediatric patients and are the focus of this article.

Transitional zone pull through: surgical pathology considerations

Incomplete resection of the transitional zone (TZ) between histologically normal and aganglionic bowel in Hirschsprung disease is a putative cause of postoperative dysmotility. A review of literature indicates that diverse histopathological indexes have been used to define the TZ, and validated and reproducible diagnostic criteria have not been established. As a consequence, the proximal margin of the TZ is difficult to delimit, and the length of the TZ in a given patient depends on the diagnostic criteria used. Seromuscular biopsies are inadequate to exclude TZ, as diagnostic indexes may involve only a portion of the bowel circumference or the submucosa. Most published investigations of postoperative outcome after a TZ pull through (TZPT) conclude that the latter can cause persistent obstructive symptoms, which necessitate reoperation. However, the results of these studies are difficult to translate into clinical practice because most lack appropriate controls, and the overwhelming majority provide inadequate histopathological descriptions for reference at the time of intraoperative frozen section analysis. At present, a conservative approach based on frozen section examination of the entire proximal margin of the resection to exclude obvious subcircumferential aganglionosis (contiguous gap between ganglia of more than one-eighth of the circumference), hypoganglionosis (continuous string of myenteric ganglia comprised of 1 or 2 ganglion cells without surrounding neuropil), or hypertrophic submucosal nerves (>2 nerves with widths ≥40 μm per high-power field) seems prudent. Well-controlled studies to correlate proximal margin histology, especially subtle anatomic or immunohistochemical changes, with postoperative outcome are needed.

Laparoscopic and transanal pull-through for Hirschsprung disease

The surgical correction of Hirschsprung disease has undergone a complete evolution in the past decade. Refinements in the performance of both transanal and laparoscopic procedures have tremendously facilitated the advancement of these surgeries. This chapter presents the history of these procedures, and then discusses the various approaches and details of these techniques.