CPT code 44160 – Partial colectomy with terminal ileum removal

Key Takeaways

CPT 44160 is open-approach only: partial colectomy with terminal ileum removal and ileocolostomy creation

Key differentiator from 44140: 44160 requires terminal ileum resection; 44140 does not

90-day global period applies; modifier -22 is the most common add-on for documented complexity

Pabau’s claims management software helps surgical billing teams catch code-selection errors before submission

CPT code 44160: Official descriptor and procedure overview

CPT code 44160 is defined by the American Medical Association (AMA) as: Colectomy, partial, with removal of terminal ileum with ileocolostomy. Three anatomical components justify the code. They are a partial colon resection, removal of the terminal ileum, and creation of an ileocolostomy anastomosis. All three are required. A procedure missing any element falls to a different code.

The procedure is most often performed as a right hemicolectomy, where the ascending colon, hepatic flexure, and terminal ileum are removed en bloc. The surgeon then creates an end-to-end or side-to-side anastomosis between the cut end of the ileum and the transverse colon. The “open” requirement is absolute: if the surgeon uses a laparoscope throughout, CPT 44160 does not apply.

CPT 44160 vs. 44140: How to tell them apart

The single most common miscoding error on colorectal claims is swapping 44160 and 44140. The deciding factor is one anatomical structure: the terminal ileum.

The operative report must document the extent of bowel resected. If it confirms terminal ileum removal and ileocolostomy creation, the procedure is 44160. If the colon is rejoined to colon and the terminal ileum is not removed, 44140 applies. An end colostomy is a different code (44141 or 44143).

CPT 44160 vs. 44205: Open vs. laparoscopic colectomy codes

CPT 44205 is the direct laparoscopic equivalent of 44160: Laparoscopy, surgical; colectomy, partial, with removal of terminal ileum with ileocolostomy. Assign 44205 when the surgeon completes the resection entirely laparoscopically, including the anastomosis, without converting to open. CPT 44204 is a different code: laparoscopic partial colectomy with anastomosis, with no terminal ileum removed.

Lap-to-open conversion: when a surgeon begins laparoscopically but converts to open, assign the open code (44160). The operative report must document the reason for conversion and confirm that the open phase completed the procedure. Do not split the work between 44160 and 44205 for a single operative session.

Applicable modifiers for CPT code 44160

Modifier selection for CPT 44160 follows standard major-surgery rules from the AAPC CPT coding guidelines. The table below lists modifiers commonly appended and the documentation each requires.

Note on -LT/-RT: site-specific laterality modifiers do not apply to abdominal intestinal procedures. The colon has no bilateral equivalent, so -LT and -RT are not used with 44160.

ICD-10 diagnosis codes commonly paired with CPT 44160

Every 44160 claim requires a diagnosis code that establishes medical necessity for the right-sided resection. Payers use ICD-10-CM pairing to determine whether the procedure was clinically appropriate. The table below covers the most common diagnoses billed alongside this code.

Select the most specific available ICD-10-CM code. For cancer cases, code the primary neoplasm site first, then any relevant secondary sites or metastatic involvement. Vague codes like K92.1 (melena) alone will not establish medical necessity for a bowel resection.

Medicare reimbursement and fee schedule for CPT 44160

The CMS Medicare Physician Fee Schedule (MPFS) sets payment rates for CPT 44160 using relative value units (RVUs). Rates below reflect national averages and are adjusted by geographic practice cost index (GPCI) for each locality. Always verify current rates directly in the MPFS lookup tool, as they update annually on January 1.

Verify current RVU values using the FastRVU 2026 lookup tool before quoting reimbursement to surgeons or revenue cycle teams. Commercial payers (Aetna, BCBS, Cigna, UnitedHealthcare) negotiate their rates contract by contract, and those rates vary widely.

Submitting claims through electronic claims via Claim.MD, Pabau’s integrated clearinghouse, enables real-time eligibility verification and tracks ERA remittance data. Your team can then catch underpayments before the 90-day global window closes. Pabau’s claims management software connects directly to Claim.MD to validate CPT-ICD-10 pairing before the claim leaves the practice.

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Pabau’s integrated claims workflow validates CPT code selection, ICD-10 pairing, and modifier requirements before submission, so 44160 claims reach payers clean the first time.

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Prior authorization requirements for CPT 44160

Medicare does not require prior authorization for CPT 44160 in most circumstances, but major commercial payers typically do. Requirements vary by plan and state, so verify with each payer before scheduling elective cases.

The clinical documentation package most payers require for prior authorization includes:

• A confirmed diagnosis with ICD-10-CM code supported by recent imaging, pathology, or endoscopy findings
• Documentation of failed conservative management where applicable (for Crohn’s disease or diverticular disease, prior medical therapy records)
• The surgeon’s operative plan specifying open approach, extent of resection, and planned anastomosis
• Anesthesia pre-op clearance for ASA Class III or higher patients (some payers require this separately)
• For oncologic indications: multidisciplinary tumor board or oncology consultation note

Emergency cases presenting with obstruction, perforation, or volvulus are typically exempt from prior authorization requirements. Document the emergent nature explicitly in the operative record and in the authorization request if the payer requires retrospective authorization.

Tracking prior authorization status against scheduled surgical dates is where practices most often lose revenue. Audit open authorizations against the surgical schedule each week. Cases booked more than 30 days out need the closest watch, because the payer’s authorization window may expire before the procedure date. Consistent medical billing compliance processes at the scheduling stage prevent the most common post-surgical authorization denials.

Common claim denial reasons for CPT code 44160 and how to avoid them

Most 44160 denials fall into five categories. Each has a specific prevention step that can be built into a pre-submission workflow.

Building a structured denial management workflow for colorectal cases catches the 44140/44160 confusion at the coding audit stage. That happens before the claim reaches the payer, not after. Reviewing common denial codes in medical billing alongside your remittance reports helps identify patterns across the surgical schedule, not just individual claims.

Documentation requirements: What the operative report must include

CPT 44160 cannot be supported without a complete operative report. Auditors and payers review these elements to confirm the code is justified.

• Surgical approach confirmed as open: the report must state the incision type (typically midline laparotomy) and confirm no laparoscopic component completed the resection
• Extent of colon resected: identify the anatomical boundaries (e.g., cecum through hepatic flexure, or cecum and ascending colon) with margins noted
• Terminal ileum resection confirmed: document how much ileum was removed and what the proximal resection margin was
• Anastomosis type and technique: confirm ileocolostomy creation; state whether hand-sewn or stapled, and the configuration (end-to-end, side-to-side, end-to-side)
• Intraoperative findings: document the pathology encountered (tumor size and location, extent of Crohn’s involvement, degree of inflammation, presence of adhesions)
• Any additional procedures: list separately any lysis of adhesions, diverting ileostomy creation, or other concurrent procedures that may affect code selection or modifier use

A superbill documentation workflow has the surgeon confirm approach, resection extent, and anastomosis type before the case is closed. That cuts the chart-chasing after the operative note is dictated. Building this into the post-op sign-off checklist means billing teams receive the information they need on the same day as the procedure.

Bundling and unbundling rules for CPT code 44160

CMS National Correct Coding Initiative (NCCI) edits define which procedures the 44160 payment already includes. Those procedures cannot be billed separately without a modifier exception. Violating these rules triggers automatic bundling denials.

Procedures bundled into 44160 (cannot be billed separately)

• Surgical exploration of the abdomen (already inherent to an open colectomy)
• Standard wound closure (fascial and skin closure is included)
• Intraoperative colonoscopy performed solely to localize the resection site
• Routine drain placement at the anastomosis site

Procedures that may be separately reportable

• Diverting loop ileostomy: this may be separately reportable when it is clinically necessary and documented as a distinct decision, not incidental to the anastomosis. Confirm it against current NCCI edits and append modifier -51 to the secondary code.
• Lysis of adhesions: this is separately reportable only when it is extensive and performed before the resection can begin. The operative note must document the extent of adhesions and the time spent on lysis as a distinct operative phase.
• Liver biopsy or peritoneal sampling: separately reportable when performed for oncologic staging at the same session

Always verify NCCI edits against the current CMS quarterly update before billing secondary codes with 44160. The NCCI Policy Manual is updated quarterly and edits can change between fiscal years. An effective revenue cycle management process for surgical specialties includes a scheduled NCCI edit review each quarter alongside the CPT code update cycle. A clean claim submission checklist built into the billing workflow is the fastest way to catch bundling issues before they reach the payer.

Conclusion

CPT code 44160 requires precise operative documentation: open approach confirmed, terminal ileum resection measured, and ileocolostomy creation stated. Three failure points come up most often. Coders confuse it with 44140, apply it to laparoscopic cases, or submit secondary codes that NCCI bundles into the primary payment.

Pabau’s integrated claims workflow validates CPT and ICD-10 pairing before claims leave the practice and flags modifier requirements. It also tracks ERA remittance data through the 90-day global period. To see how Pabau handles colorectal and surgical billing workflows, book a demo with the team.

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