Complicated Coding: Postoperative Ileus

By William C. Fiala, MA, CCS-P, CPC, RMA, and Kristine N. Kraft, DC, RMA

Complication coding is “considered to be one of the more challenging aspects of coding,” as an article in ICD10monitor once put it.1 The reporting of complication codes brings with it certain risks to providers and institutions, from adverse report card grades to increased liability and decreased payment. As Vanessa Fuhrmans reported in the Wall Street Journal, some insurers go so far as to refuse payment “for care triggered by some complications they believe hospitals should prevent.”2 Coding professionals need to continue to expand their knowledge in pathophysiology and to continue developing lines of communication with providers to ensure any reporting of complication codes is accurate. This article will review one possible complication—postoperative ileus—and the circumstances of coding for it.

In reviewing medical dictionaries, ileus is frequently defined as an obstruction of the bowel.3,4 Dr. Edward Livingston and Dr. Edward Passaro, in their 1990 discussion, defined it as “a state of inhibited bowel function” wherein there is a “functional inhibition of propulsive bowel activity.”5 The physicians further defined postoperative ileus as “the uncomplicated ileus occurring following surgery, resolving spontaneously within two to three days” lasting “transiently in the small bowel, for 24-48 hours in the stomach, and 48-72 hours in the colon.”6 Other authors have observed a “general consensus that some degree of postoperative ileus is a normal obligatory and physiologic response to abdominal surgery” and a “generally benign condition that resolves without serious sequelae.”7 The expected result of surgery may have some prophylactic address:

Nasogastric suction for the relief of bowel obstruction was introduced in 1884. Nasogastric intubation had a tremendous impact… and became the standard after abdominal procedures where ileus is a problem. It was, and remains so common that [it] is still routinely employed as prophylaxis.8

Coding professionals should note that, at least in the short term, postoperative ileus can be a normal and expected result of surgery for which prophylactic measures may routinely be ordered.

With a reasonable definition of postoperative ileus, it is easier to understand what constitutes a complication. In their 2004 proposal for a classification of surgical complications, Drs. Dindo, Demartines, and Clavien defined a surgical complication as “any deviation from the normal postoperative care.”9 Health information management professionals similarly define a complication as a circumstance “likely to increase the intensity of services needed to care for patients” and “a condition arising during the hospitalization that modifies the course of the patient’s illness or the medical care required.”10,11 Key elements from those definitions include “deviation from normal,” “increase the intensity,” and “modifies the course.”

ICD-10-CM coding guidelines add another component to the definition of a complication: a link between the deviation, increased intensity, or modified care plan and the prior care provided—in this case, the surgery. According to the guidelines:

Code assignment is based on the provider’s documentation of the relationship between the condition and the care or procedure, unless otherwise instructed by the classification. The guideline extends to any complications of care, regardless of the chapter the code is located in. It is important to note that not all conditions that occur during or following medical care or surgery are classified as complications. There must be a cause-and-effect relationship between the care provided and the condition, and an indication in the documentation that it is a complication.12

A surgical complication is a circumstance in which there is a modification to the patient’s treatment plan that takes it beyond normal postoperative care and for which the provider documents a clear relationship between the need for the modification and the preceding procedure.

Armed now with definitions of postoperative ileus and a surgical complication, how would a coding professional report the circumstance when the provider documents “postoperative ileus?”

Since 2012, reporting the circumstance in ICD-9-CM appeared fairly straightforward; 2012 saw the introduction of a new code—997.40—along with subterm or essential modifier entries in the alphabetic index under the main term “ileus” that read “following gastrointestinal surgery” and “postoperative” and pointed to 997.49. Category code 997 is identified as “complications affecting specified body systems, not elsewhere classified.” It seems as though the default for a postoperative ileus was that the circumstance was a complication whether or not it lasted less than three days, was a “normal obligatory and physiologic response,” did not require any change in the normal postoperative care or treatment plan, and was not specifically identified by the provider as having a causal relationship to the procedure. Similarly, the ICD-10-CM alphabetic index under the main term “ileus” has a subterm or essential modifier “postoperative” and points to code K91.89 with a description of “other postprocedural complication and disorders of the digestive system” and a “use additional code” note. Fortunately, the ICD-10-CM guidelines provide one more very critical bit of instruction: “Query the provider for clarification, if the complication is not clearly documented.”13

The documentation of “postoperative ileus” presents an excellent clinical documentation improvement moment and an opportunity for coding professionals and providers to work together. Coders should not assume that the words “postoperative ileus” always refer to a complication as defined above, and queries regarding clarification of the documentation should be made. One coding professional reports that providers are beginning to document “expected ileus,” documentation that is consistent with the idea that the ileus is, as Drs. Kalff, Wehner, and Litkouhi suggest, “a normal obligatory and physiologic response” requiring no additional resources beyond routine postoperative care and prophylaxis, and documentation that provides some clarity to coders.14 Coding professionals should work with providers at their practice or facility to establish clear and consistent documentation such that the circumstance of an expected postoperative ileus—the normal two- to three-day event requiring no additional resources—can be clearly and easily distinguished from a complication of surgery—a longer postoperative ileus that does require deviation from the normal postoperative care—thus allowing the encounter to be coded quickly and correctly.


  1. ICD10monitor. “Postoperative Complications: It’s complicated.” March 25, 2016.
  2. Fuhrmans, Vanessa. “Insurers Stop Paying for Care Linked to Errors.” Wall Street Journal. Jan 15, 2008.
  3. Stedman’s Concise Medical Dictionary for the Health Professions, Third Edition. Baltimore, MD: Williams & Wilkins, 1997.
  4. Taber’s Cyclopedic Medical Dictionary: 20th Edition. Philadelphia, PA: F.A. Davis, 2005.
  5. Livingston, Edward and Edward Passaro. “Postoperative Ileus.” Digestive Diseases and Sciences 35, no. 1 (January 1990): 121-132.
  6. Ibid, page 122.
  7. Kalff, Jörg C. et al. “Postoperative Ileus.” UpToDate. July 17, 2017.
  8. Livingston, Edward and Edward Passaro. “Postoperative Ileus.” Page 126.
  9. Dindo, Daniel, Nicolas Demartines, and Pierre-Alain Clavien. “Classification of Surgical Complications: A New Proposal with Evaluation in a Cohort of 6336 Patients and Results of a Survey.” Annals of Surgery 240, no. 2 (August 2004): 206.
  10. Gregg Fahrenholz, Cheryl and Ruthann Russo, ed. Documentation for Health Records. Chicago, IL: AHIMA, 2013: 415.
  11. Huffman, Edna. Health Information Management, 10th ed, revised by AHIMA. Berwyn, IL: Physician’s Record Company, 1994: 234.
  12. Centers for Medicare and Medicaid Services. ICD-10-CM Official Guidelines for Coding and Reporting.
  13. Ibid.
  14. HCPro. “Q&A: Resolving coding postoperative ileus worries with documentation.” CDI Strategies. March 31, 2011.

William C. Fiala ( is professor of practice, allied health technology, at University of Akron. Kristine N. Kraft ( is director, medical assisting technology and interim director, School of Allied Health Technology, at the University of Akron.

Article citation:
Fiala, William C. “Complicated Coding: Postoperative Ileus.” Journal of AHIMA 90, no. 4 (April 2019): 44-45.