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CPT 45113: Partial Proctectomy with Ileoanal Anastomosis and Ileal Pouch

CPT code 45113 represents a complex colorectal surgery: partial proctectomy with mucosal resection, ileoanal anastomosis, and creation of an ileal reservoir (pouch), with optional loop ileostomy. This procedure is clinically significant for management of refractory inflammatory bowel disease and rectal cancer and carries implications for operative planning, postoperative care, and payer authorization due to its complexity and inpatient resource needs. Nationally, this code is relevant for hospitals, colorectal surgeons, and payers managing high-acuity gastrointestinal surgical episodes.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context for the procedure, typical sites of service, commonly reported modifiers, and where available, payer coverage considerations. The publication also outlines benchmarks and policy-relevant points that affect utilization, billing compliance, and claims adjudication for major colorectal reconstructive surgery.

This summary frames what clinicians, billing staff, and policy analysts need to know about coding 45113, how it is used in the care pathway for Crohn colitis and rectal cancer, and the operational issues that commonly arise when this high-resource inpatient procedure is billed.

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Billing Code Overview

CPT code 45113 describes a surgical procedure in which the provider performs a partial proctectomy with resection of rectal mucosa, constructs an ileoanal anastomosis, and creates an ileal reservoir (pouch). The procedure may include a loop ileostomy to divert fecal stream but the ostomy may not be performed in every case. This operation is performed to treat conditions such as Crohn colitis or rectal cancer.

Service type: Major abdominal and colorectal surgery involving bowel resection and ileoanal reconstruction
Typical site of service: Hospital operating room or inpatient surgical facility

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CPT 45113: Partial Proctectomy with Ileoanal Anastomosis and Ileal Pouch

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Billing Code Overview

Service type: Major abdominal and colorectal surgery involving bowel resection and ileoanal reconstruction
Typical site of service: Hospital operating room or inpatient surgical facility

Clinical & Coding Specifications

Clinical Context

A 48-year-old patient with refractory ulcerative colitis and dysplastic changes in the rectum is scheduled for a restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). The surgical team plans a total proctocolectomy with mucosal proctectomy of the residual rectal cuff, construction of a J-pouch from the terminal ileum, and ileoanal anastomosis. A loop ileostomy may be created intraoperatively for temporary fecal diversion. Preoperative workflow includes colorectal surgical consultation, colonoscopic evaluation with biopsy confirming dysplasia, bowel preparation, anesthesia pre-op assessment, and informed consent highlighting potential for stoma creation. Typical intraoperative steps include induction of general anesthesia, midline or lower abdominal incision (or laparoscopic ports), mobilization and resection of the colon and rectum with mucosectomy of the remaining rectal cuff, construction of an ileal reservoir (pouch), handsewn or stapled ileoanal anastomosis, and possible formation of a loop ileostomy. Postoperative workflow includes recovery in PACU, inpatient monitoring for anastomotic integrity, pain control, early mobilization, stoma care teaching if applicable, and outpatient follow-up for pouch function and ileostomy takedown planning if a diverting stoma was created.

Coding Specifications

Modifier	Description	When to Use
`00`	No modifier	Standard reporting when no modifier applies to the service
`22`	Increased procedural services	Use when work, time, and complexity substantially exceed typical for `45113` due to extensive adhesions or unexpected complexity
`23`	Unusual anesthesia	Use when general anesthesia is contraindicated and a medically necessary unusual anesthesia technique is used
`26`	Professional component	Rarely used for surgical procedure codes; apply when billing only the professional component in a split billing arrangement
`50`	Bilateral procedure	Not typically used for `45113` (single-organ procedure); reserve only if payer-specific rules require bilateral reporting for simultaneous bilateral organ work
`51`	Multiple procedures	Use when additional distinct surgical CPT codes are reported on same operative date to indicate multiple procedures
`52`	Reduced services	Use if the procedure is partially reduced or not completed as originally planned
`53`	Discontinued procedure	Use when procedure is started but discontinued for extenuating circumstances prior to completion
`59`	Distinct procedural service	Use to indicate a procedure or service that is distinct and separate from other services on same day (selectively applied with other CPTs)
`62`	Two surgeons	Use when two surgeons work together as primary surgeons performing distinct operative work on the same patient
`63`	Procedure performed on infants less than 4 kg	Rarely applicable; use only when patient meets weight criteria and payer requires modifier
`78`	Return to OR for related procedure during global period	Use when the patient returns to the OR for a related procedure during the global postoperative period
`80`	Assistant surgeon	Use to identify a surgical assistant participating in the procedure
`82`	Assistant surgeon when qualified resident unavailable	Use when no qualified resident is available and an assistant surgeon is used

Taxonomy Code	Specialty	Notes
207RN0400X	Colon & Rectal Surgery	Primary specialty performing restorative proctocolectomy and IPAA
208U00000X	General Surgery	Common specialty performing colectomy and pouch construction in many centers
207L00000X	Surgical Oncology	Performs resections for rectal cancer indications when oncology-focused care is required
207K00000X	Gastroenterology (procedural)	Involved preoperative diagnostics (endoscopy, biopsy) but not typically the operating surgeon
363L00000X	Anesthesiology	Provides perioperative anesthesia care and billing for anesthesia services

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`K51.219`	Ulcerative colitis, unspecified, without complications	Ulcerative colitis is a primary indication for restorative proctocolectomy with IPAA to manage refractory disease or dysplasia
`K50.919`	Crohn's disease, unspecified, without complications	Crohn colitis may prompt extensive resection when disease is limited to the colon and rectum and pouch surgery is considered in select cases
`C20`	Malignant neoplasm of rectum	Rectal cancer involving the rectum may necessitate proctectomy with colo/ileoanal reconstruction when oncologically appropriate
`D01.3`	Carcinoma in situ of rectum and rectosigmoid junction	High-grade dysplasia or carcinoma in situ can be an indication for proctectomy and pouch formation in select patients
`K62.5`	Hemorrhage of anus and rectum	Severe refractory bleeding from rectal disease may be an indication for surgical resection when medical therapy fails

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`44140`	Colectomy, partial; with anastomosis	May be used when segmental colectomy with anastomosis is performed in place of or prior to total proctocolectomy in staged management
`44160`	Colectomy, total, abdominal, with ileorectal anastomosis	Alternative restorative approach when rectum is preserved and ileorectal anastomosis is performed instead of IPAA
`44207`	Laparoscopy, surgical; colectomy, partial, with anastomosis	Laparoscopic approach codes when the colectomy and pouch formation are performed minimally invasively
`44625`	Proctectomy, partial with anastomosis; low anterior resection	May be reported when low rectal resection with colo/ileoanal anastomosis is performed as part of oncologic management
`44120`	Enterectomy, resection of small intestine; single resection and anastomosis	May be used for limited small-bowel resections required during pouch construction or adhesiolysis

CPT 45100: Anal Approach Biopsy of Anorectal Wall

CPT-45108-ANORECTAL-TUMOR-EXCISION

CPT 45108: Excision of Anorectal Muscle Tumor

CPT-45110-ABDOMINOPERINEAL-RESECTION-WITH-COLOSTOMY

CPT 45110: Abdominoperineal Resection with Colostomy

CPT-45111-PARTIAL-RECTAL-RESECTION-ABDOMINAL-APPROACH

CPT 45111: Partial Rectal Resection, Abdominal Approach

CPT-45112-RECTAL-RESECTION-COLON-TO-ANUS-ANASTOMOSIS

CPT 45112: Rectal Resection with Colonic Anastomosis to Anus

CPT-45114-RECTAL-RESECTION-ANASTOMOSIS-ABDOMINAL-SACRAL-APPROACH

CPT 45114: Rectal Resection and Colon-Rectal Anastomosis, Abdominal and Sacral Approach

CPT-45116-POSTERIOR-APPROACH-RECTAL-RESECTION-ANASTOMOSIS

CPT 45116: Posterior Rectal Resection with Colorectal Anastomosis

CPT-45119-RESTORATIVE-PROCTOCOLECTOMY-WITH-COLONIC-POUCH

CPT 45119: Restorative Proctocolectomy with Colonic Pouch

CPT-45120-ABDOMINOPERINEAL-RECTAL-RESECTION-COLON-ANASTOMOSIS

CPT 45120: Abdominoperineal Rectal Resection with Colon-Anus Anastomosis

CPT-45121-PULL-THROUGH-RESECTION-ABDOMINAL-PERINEAL-COLORECTAL-ANASTOMOSIS

CPT 45121: Pull-Through Resection with Colorectal Anastomosis

Showing 1–10 of 19

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`00`	No modifier	Standard reporting when no modifier applies to the service
`22`	Increased procedural services	Use when work, time, and complexity substantially exceed typical for `45113` due to extensive adhesions or unexpected complexity
`23`	Unusual anesthesia	Use when general anesthesia is contraindicated and a medically necessary unusual anesthesia technique is used
`26`	Professional component	Rarely used for surgical procedure codes; apply when billing only the professional component in a split billing arrangement
`50`	Bilateral procedure	Not typically used for `45113` (single-organ procedure); reserve only if payer-specific rules require bilateral reporting for simultaneous bilateral organ work
`51`	Multiple procedures	Use when additional distinct surgical CPT codes are reported on same operative date to indicate multiple procedures
`52`	Reduced services	Use if the procedure is partially reduced or not completed as originally planned
`53`	Discontinued procedure	Use when procedure is started but discontinued for extenuating circumstances prior to completion
`59`	Distinct procedural service	Use to indicate a procedure or service that is distinct and separate from other services on same day (selectively applied with other CPTs)
`62`	Two surgeons	Use when two surgeons work together as primary surgeons performing distinct operative work on the same patient
`63`	Procedure performed on infants less than 4 kg	Rarely applicable; use only when patient meets weight criteria and payer requires modifier
`78`	Return to OR for related procedure during global period	Use when the patient returns to the OR for a related procedure during the global postoperative period
`80`	Assistant surgeon	Use to identify a surgical assistant participating in the procedure
`82`	Assistant surgeon when qualified resident unavailable	Use when no qualified resident is available and an assistant surgeon is used

Taxonomy Code	Specialty	Notes
207RN0400X	Colon & Rectal Surgery	Primary specialty performing restorative proctocolectomy and IPAA
208U00000X	General Surgery	Common specialty performing colectomy and pouch construction in many centers
207L00000X	Surgical Oncology	Performs resections for rectal cancer indications when oncology-focused care is required
207K00000X	Gastroenterology (procedural)	Involved preoperative diagnostics (endoscopy, biopsy) but not typically the operating surgeon
363L00000X	Anesthesiology	Provides perioperative anesthesia care and billing for anesthesia services

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`K51.219`	Ulcerative colitis, unspecified, without complications	Ulcerative colitis is a primary indication for restorative proctocolectomy with IPAA to manage refractory disease or dysplasia
`K50.919`	Crohn's disease, unspecified, without complications	Crohn colitis may prompt extensive resection when disease is limited to the colon and rectum and pouch surgery is considered in select cases
`C20`	Malignant neoplasm of rectum	Rectal cancer involving the rectum may necessitate proctectomy with colo/ileoanal reconstruction when oncologically appropriate
`D01.3`	Carcinoma in situ of rectum and rectosigmoid junction	High-grade dysplasia or carcinoma in situ can be an indication for proctectomy and pouch formation in select patients
`K62.5`	Hemorrhage of anus and rectum	Severe refractory bleeding from rectal disease may be an indication for surgical resection when medical therapy fails

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`44140`	Colectomy, partial; with anastomosis	May be used when segmental colectomy with anastomosis is performed in place of or prior to total proctocolectomy in staged management
`44160`	Colectomy, total, abdominal, with ileorectal anastomosis	Alternative restorative approach when rectum is preserved and ileorectal anastomosis is performed instead of IPAA
`44207`	Laparoscopy, surgical; colectomy, partial, with anastomosis	Laparoscopic approach codes when the colectomy and pouch formation are performed minimally invasively
`44625`	Proctectomy, partial with anastomosis; low anterior resection	May be reported when low rectal resection with colo/ileoanal anastomosis is performed as part of oncologic management
`44120`	Enterectomy, resection of small intestine; single resection and anastomosis	May be used for limited small-bowel resections required during pouch construction or adhesiolysis

CPT 45100: Anal Approach Biopsy of Anorectal Wall

CPT-45108-ANORECTAL-TUMOR-EXCISION

CPT 45108: Excision of Anorectal Muscle Tumor

CPT-45110-ABDOMINOPERINEAL-RESECTION-WITH-COLOSTOMY

CPT 45110: Abdominoperineal Resection with Colostomy

CPT-45111-PARTIAL-RECTAL-RESECTION-ABDOMINAL-APPROACH

CPT 45111: Partial Rectal Resection, Abdominal Approach

CPT-45112-RECTAL-RESECTION-COLON-TO-ANUS-ANASTOMOSIS

CPT 45112: Rectal Resection with Colonic Anastomosis to Anus

CPT-45114-RECTAL-RESECTION-ANASTOMOSIS-ABDOMINAL-SACRAL-APPROACH

CPT 45114: Rectal Resection and Colon-Rectal Anastomosis, Abdominal and Sacral Approach

CPT-45116-POSTERIOR-APPROACH-RECTAL-RESECTION-ANASTOMOSIS

CPT 45116: Posterior Rectal Resection with Colorectal Anastomosis

CPT-45119-RESTORATIVE-PROCTOCOLECTOMY-WITH-COLONIC-POUCH

CPT 45119: Restorative Proctocolectomy with Colonic Pouch

CPT-45120-ABDOMINOPERINEAL-RECTAL-RESECTION-COLON-ANASTOMOSIS

CPT 45120: Abdominoperineal Rectal Resection with Colon-Anus Anastomosis

CPT-45121-PULL-THROUGH-RESECTION-ABDOMINAL-PERINEAL-COLORECTAL-ANASTOMOSIS

CPT 45121: Pull-Through Resection with Colorectal Anastomosis

Showing 1–10 of 19

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

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CPT 45113: Partial Proctectomy with Ileoanal Anastomosis and Ileal Pouch

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Billing Code Overview

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CPT 45113: Partial Proctectomy with Ileoanal Anastomosis and Ileal Pouch

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Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

CPT 45113: Partial Proctectomy with Ileoanal Anastomosis and Ileal Pouch

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Billing Code Overview

CPT 45113: Partial Proctectomy with Ileoanal Anastomosis and Ileal Pouch

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Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does CPT 45113 represent and when is it used?

Which specialties typically perform or participate in services related to CPT 45113?

Which modifiers are commonly used with CPT 45113 and in what situations?

What related CPT codes might be reported alongside or instead of 45113?

What are the typical clinical indications and preoperative steps for a procedure billed as CPT 45113?

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

What does CPT 45113 represent and when is it used?

Which specialties typically perform or participate in services related to CPT 45113?

Which modifiers are commonly used with CPT 45113 and in what situations?

What related CPT codes might be reported alongside or instead of 45113?

What are the typical clinical indications and preoperative steps for a procedure billed as CPT 45113?

References