The operation in question is the pull-through procedure for Hirschsprung disease, a congenital condition in which nerve cells are missing from part of the bowel. Without these ganglion cells, the affected segment cannot relax and propel stool, causing severe obstruction. The definitive treatment involves removing the abnormal segment and pulling healthy bowel down to the anus, a procedure first described in detail by Orvar Swenson in the mid-twentieth century. When performed with meticulous technique, the operation was historically associated with excellent function: in the largest published series, a landmark 40-year multinational study of 880 Swenson procedures, good function, defined as one to three stools per day without incontinence, was recorded in 89 percent of patients, with no cases of urinary or sexual dysfunction.

Yet as the operation spread and evolved, outcomes became troublingly variable. The procedure was modified to avoid preliminary colostomies, performed at younger ages including in neonates, adapted for laparoscopy, and increasingly carried out through a transanal approach for the dissection and anastomosis. With each modification came new names, new codes, and new sources of confusion. Recent reports now describe incontinence rates ranging from 15 to 40 percent and constipation in roughly a quarter of patients. Neonatal operations have been linked to higher rates of anastomotic complications and long-term incontinence approaching 36 percent. Known technical culprits include pulling through bowel that still contains a transition zone, which causes constipation, and injury to the anal sphincter, which causes incontinence. What has been missing is a systematic way to identify which technical steps prevent these complications in the first place.

Part of the difficulty lies in how operations are categorized. The billing code CPT 45120 covers all proctectomies with pull-through performed without laparoscopy, regardless of the patient’s age, the type of anastomosis, or whether the procedure was staged. The laparoscopic equivalent, CPT 45499, is a generic unlisted code. Two operations sharing the same code may differ substantially in technique, and comparisons based on procedure names or codes therefore carry considerable hidden error. Edward J. Doolin, the author of the new study, hypothesized that the answer lay not in the codes but in the words: the unstructured operative report, dictated by the attending surgeon who performed the operation, captures exactly those nuances that templated forms and billing categories erase.

To test this idea, Doolin turned to content analysis, a research method that identifies words or phrases in a text that carry significance and then quantifies their relationships with outcomes. The approach can be inductive, mining unstructured text to discover new patterns, or deductive, using predetermined text sets to evaluate a hypothesis. This study took the deductive route. From Swenson’s original detailed description of the operation, Doolin abstracted five text phrases considered unique and essential to an effective pull-through: dissecting tissue off the rectal wall close to the rectum itself, continuing the dissection to the level of the internal sphincter, everting the rectum through the anus for maximum exposure, confirming that the dissection is complete, and dividing the rectum two to three centimeters proximal to the mucocutaneous margin. Each phrase corresponds to a physical maneuver that protects the pelvic nerves and the anal sphincter while ensuring complete removal of the diseased bowel.

The study population was drawn from patients at the Children’s Hospital of Philadelphia who underwent proctectomy and pull-through for Hirschsprung disease between 2007 and 2023. Of 160 charts reviewed, 76 were excluded because of extensive aganglionosis extending beyond the sigmoid colon, surgical complications such as leaks or strictures that would independently impair sphincter function, medical comorbidities such as Down syndrome or motility disorders, or inadequate records. The remaining 84 patients, operated on at an average age of seven months, formed the study cohort. Eleven full-time attending surgeons performed the operations, and every operative report was dictated in free text by the surgeon who was present for the entire procedure. Crucially, the investigator reviewed records under anonymized case numbers so that the assessment of outcomes could not be influenced by knowledge of the operative details.

Bowel function was assessed from at least three consistent clinical encounters, including office notes, hospital records, and letters, between one and three years after surgery. This window was deliberately chosen: in the first year, frequent stools and poor control are common as the intestine recovers, while a decade after surgery, accommodation, treatments, and learned skills make normal function common regardless of the repair method, both of which would blur the signal of surgical technique. Each patient was assigned to one of three categories: normal bowel function, meaning one to three spontaneous bowel movements daily without enemas, irrigations, or medications such as botulinum toxin; constipation, meaning extended days without stool, distension, abnormal imaging, or the need for irrigations or toxin injections; or incontinence, meaning more than three stools daily with soiling and excessive diaper dependence.

The results were striking. Overall, 47 of the 84 patients, or 55 percent, achieved normal bowel function, while 12 were classified as constipated and 25, or 29 percent, as incontinent. But when any one of the five key text phrases appeared in the operative record, the picture changed dramatically. Normal bowel function was reported in 80 to 90 percent of patients whose records documented one of these maneuvers, compared with only 30 to 40 percent when the phrase was absent, a difference that reached statistical significance. Incontinence was rare, below 10 percent, when a phrase was documented, but ranged from 35 to 45 percent when it was missing. Constipation also trended lower, at 6 to 12 percent versus 25 to 29 percent, though this difference did not reach statistical significance, likely because constipation can arise from inherent dysfunction of the preserved anus regardless of technique.

These findings carry a double significance. Clinically, they suggest that the nuanced steps emphasized in Swenson’s original description, close dissection along the rectal wall, complete dissection verified by eversion of the rectum, and a precisely measured resection level that preserves the anal sphincter, remain the decisive factors for good function, applicable across all modern approaches whether open, laparoscopic, or transanal. Methodologically, they demonstrate that unstructured operative reports, long dismissed as inconsistent and inferior to templated documentation, are in fact a recoverable data source capable of supporting rigorous outcome research. Even carefully crafted synoptic reporting forms, such as the one developed by the American Pediatric Surgical Association for the Hirschsprung pull-through, list procedures by name but omit the very factors studied here, rendering them ineffective for investigating functional outcomes like incontinence.

The educational implications may prove equally important. Surgical educators have long noted deficiencies in resident dictation, which partly motivated the shift toward templates, but templates strip away the detail that complex operations demand. Doolin argues that composing a thoughtful, unstructured operative note is itself a valuable learning exercise, forcing the surgeon to reflect on what was done and why, in the spirit of the reflective practitioner. Existing assessment tools such as the Ottawa Surgical Competency Operating Room Evaluation and the Zwisch Model rely on observations by teachers alone, whereas the content of a dictated report measures what the surgeon actually understood. As content analysis and natural language processing mature, the humble operative dictation may become a powerful instrument for studying surgical technique, minimizing bias, and ensuring that the subtle maneuvers separating success from lifelong incontinence are taught, documented, and preserved.

Subject of Research: Content analysis of unstructured operative reports to identify surgical technique factors affecting outcomes of pull-through surgery for Hirschsprung disease

Article Title: Content analysis of unstructured operative records can evaluate nuanced techniques in complex operations

Article References: Doolin, E. J. (2026). Content analysis of unstructured operative records can evaluate nuanced techniques in complex operations. Global Surgical Education – Journal of the Association for Surgical Education, 5(1), Article 129. https://doi.org/10.1007/s44186-026-00530-6

Image Credits: AI Generated

DOI: 10.1007/s44186-026-00530-6

Keywords: Hirschsprung disease, pull-through surgery, content analysis, unstructured operative reports, pediatric surgery, fecal incontinence, anal sphincter preservation, surgical education, Swenson procedure, natural language processing, operative notes, surgical outcomes

Hirschsprung disease arises when enteric neural crest cells fail to migrate and differentiate properly during development, leaving the distal intestine devoid of the myenteric and submucosal nerve plexuses that normally coordinate peristalsis. The result is abdominal distension and refractory constipation, typically treated by surgically removing the aganglionic segment and reconstructing the bowel. Yet a substantial proportion of patients continues to suffer long-term complications, including enterocolitis, anastomotic strictures, fecal soiling, persistent constipation, and the need for reoperation. These persistent problems have intensified the search for the molecular mechanisms underlying the disease, and the new work points squarely at the glial microenvironment.

Enteric glial cells are the most abundant non-neuronal component of the enteric nervous system, and they are far more than passive scaffolding. They maintain epithelial integrity, coordinate neuro-immune signaling, and support neuronal survival. Recent single-cell RNA sequencing studies have revealed that glia exist in multiple transcriptionally distinct states, some of which resemble reactive microglia in the brain. In tumor-associated macrophages, researchers have described a CXCL9-to-SPP1 polarization axis that separates anti-inflammatory from pro-disease functional states. Whether enteric glia undergo a comparable polarization program in Hirschsprung disease had never been established, and that question became the starting point for the investigation.

The team began with an integrated single-cell transcriptomic analysis of colonic tissue from a mouse model of Hirschsprung disease based on loss of the endothelin receptor B gene, Ednrb, alongside wild-type controls. Among the five transcriptionally distinct glial subclusters they identified, one stood out: a subcluster enriched for both TXNRD1 and SPP1 that expanded markedly in disease samples, while a subcluster marked by Apoe shrank. Enrichment analyses of this expanded population highlighted extracellular matrix organization, cell adhesion, focal adhesion, and PI3K-Akt and MAPK signaling programs. Computational modeling of ligand-receptor interactions further showed that this subcluster engaged in the strongest predicted communication with enteric neurons of any glial population, including a predicted VCAM1-NCAM1 signaling axis.

To probe the regulatory logic behind this glial remodeling, the researchers turned to network-based virtual perturbation using the scTenifoldNet framework, which simulates gene knockout or overexpression within an inferred gene regulatory network. Both virtual knockout and virtual overexpression of TXNRD1 converged on regulatory programs involving redox control, ERK/MAPK-associated immediate-early response genes, and stress-associated glial features. Virtual overexpression produced a more focused pathological shift, with SPP1 emerging as the most prominently perturbed gene. These in silico results positioned TXNRD1, a central regulator of intracellular redox homeostasis, as a plausible upstream driver of the disease-associated glial state.

Human tissue evidence followed. Proteomic profiling of paired proximal dilated and stenotic colonic segments from children undergoing pull-through surgery revealed marked TXNRD1 upregulation in the stenotic, aganglionic tissue, together with significant enrichment of the MAPK signaling pathway. Validation in eight paired patient samples using quantitative PCR, western blotting, and immunofluorescence confirmed elevated TXNRD1 alongside increased phosphorylation of Raf, MEK, and ERK, while the stress kinases p38 and JNK showed no significant changes, indicating selective activation of the ERK branch of the MAPK cascade. Immunofluorescence staining also showed that SPP1 was increased and CXCL9 reduced within S100β-positive enteric glia in the stenotic segments, mirroring the single-cell findings in human tissue.

The mechanistic experiments in cultured rat enteric glial cells tied these observations together. When the researchers overexpressed TXNRD1, the cells selectively increased ERK phosphorylation, elevated their production of SPP1, suppressed CXCL9, accumulated reactive oxygen species, migrated less effectively, and secreted less glial cell line-derived neurotrophic factor, or GDNF. Treatment with the ERK inhibitor SCH772984 partially restored CXCL9 expression and blunted SPP1 upregulation, while the antioxidant N-acetyl-L-cysteine reduced ROS accumulation, dampened ERK activation, and reversed the SPP1-high/CXCL9-low polarization. Notably, ERK inhibition did not normalize ROS levels, suggesting that redox dysregulation acts upstream of ERK/MAPK signaling rather than as a downstream consequence.

The consequences for neurons were striking. In co-culture experiments with primary dorsal root ganglion neurons, TXNRD1-overexpressing glia increased neuronal apoptosis, impaired neuronal migration, reduced phosphorylation of the RET receptor and expression of its co-receptor GFRα1, downregulated the synaptic proteins PSD-95 and synaptophysin, and disrupted intracellular calcium homeostasis. Levels of the neurotrophic factors NGF and BDNF also fell in the co-culture system. Crucially, both ERK inhibition and supplementation with exogenous GDNF partially rescued these defects, implicating suppression of the GDNF/GFRα1/RET signaling axis as a key route by which the remodeled glia damage neuronal development and function.

The in vivo experiments provided the most compelling translational signal. The team generated Ednrb conditional knockout mice, which develop Hirschsprung-like phenotypes, and delivered an adeno-associated virus carrying TXNRD1-targeting shRNA by intraperitoneal injection at postnatal day 5. Knockdown of TXNRD1 markedly ameliorated the disease features, reducing abdominal distension, proximal colonic dilatation, distal stenosis, and fecal retention. Treated mice survived significantly longer, with four animals reaching the study endpoint, and fecal water content rose toward control levels, indicating improved intestinal function. At the molecular level, TXNRD1 suppression decreased SPP1, restored CXCL9, increased the neuronal marker TUJ1 and the neural crest marker p75, and upregulated the communication mediators NCAM1 and VCAM1 in the bowel.

The authors are careful to acknowledge the limitations of their work. The proteomic screen relied on only two paired patient samples, the validation cohorts were small, and the intraperitoneal viral delivery was not restricted to enteric glia, complicating cell-type-specific interpretation. Primary dorsal root ganglion neurons served as a surrogate for enteric neurons, and the temporal origins of the SPP1-high glial state remain unresolved, with lineage tracing and spatial transcriptomics needed to clarify its development. Even so, the study establishes a coherent mechanistic framework linking redox dysregulation, ERK/MAPK activation, pathological glial polarization, and neuronal dysfunction in Hirschsprung disease. By showing that enteric glia are active participants in the disease rather than passive bystanders, and that silencing TXNRD1 alleviates HSCR-like phenotypes in mice, the work nominates TXNRD1 and the glial polarization program it controls as promising targets for future therapies aimed at improving outcomes for children with this challenging disorder.

Subject of Research: The role of TXNRD1-driven enteric glial remodeling in neuronal dysfunction in Hirschsprung disease

Article Title: TXNRD1-driven enteric glial remodeling promotes neuronal dysfunction in Hirschsprung disease

Article References: Li, Y., Wang, Y., Jin, Z., Tang, C., Xia, X., Gong, Y., Du, Q., Huang, L., Li, Z., Liao, Y., He, S., Wang, B., Liu, Y., & Zheng, Z. (2026). TXNRD1-driven enteric glial remodeling promotes neuronal dysfunction in Hirschsprung disease. iScience, 29(10), Article 117636. https://doi.org/10.1016/j.isci.2026.117636

Image Credits: AI Generated

DOI: 10.1016/j.isci.2026.117636

Keywords: Hirschsprung disease, enteric glial cells, TXNRD1, SPP1, CXCL9, ERK/MAPK signaling, redox dysregulation, GDNF, single-cell RNA sequencing, enteric nervous system, Ednrb knockout mice, neurotrophic signaling