In both ICD-10-CM and ICD-9-CM, the subsections in the digestive system chapters that contain hernia codes include both acquired and congenital forms, with the exception of diaphragmatic or hiatal congenital hernias. These types of congenital hernias are reported with codes from the chapter for conditions originating in the perinatal period. In ICD-10-CM, these codes include Q40.1 Congenital hiatus hernia and Q79.0 Congenital diaphragmatic hernia. All other hernia codes for the digestive system are found in the K40-K46 subsection, which includes a note stating that hernias presenting with both gangrene and obstruction are classified as hernia with gangrene, as is the same for reporting inguinal and other hernias of the abdominal cavity in ICD-9-CM. Another similarity is the axis of coding for hernias, which are reported by type (e.g., inguinal, femoral, ventral, etc.), presentation (e.g., with or without gangrene and/or obstruction), laterality (unilateral or bilateral), and status (recurrent or not specified as recurrent).
The organization of hernia codes following these specific axes for coding is somewhat different in ICD-10-CM. The ICD-9-CM system reports each different type of hernia, with the exception of inguinal, all together under three categories that are first defined as other hernia of the abdominal cavity, either ‘with gangrene’ (category 551), or ‘with obstruction, but without mention of gangrene’ (category 552), and ‘without mention of obstruction or gangrene’ (category 553). The type of hernia, whether femoral, umbilical, ventral, or diaphragmatic, is then listed as a subcategory under these three categories, which are further subdivided by the other axes of laterality or recurrent status as appropriate. Only inguinal hernias are organized first by type under category 550, then subclassified by presentation with or without gangrene or obstruction. Fifth digits are assigned for the other axes of laterality or recurrent status. In ICD-10-CM, all hernia codes are organized first into categories by type:
- K40: Inguinal hernia
- K41: Femoral hernia
- K42: Umbilical hernia
- K43: Ventral hernia
- K44: Diaphragmatic hernia
- K45: Other abdominal hernia
- K46: Unspecified abdominal hernia
The category for the type of hernia is then further subdivided based on laterality and/or presentation. Below are some examples for inguinal hernia subcategories:
- K40.0 Bilateral inguinal hernia, with obstruction, without gangrene
- K40.1 Bilateral inguinal hernia, with gangrene
- K40.2 Bilateral inguinal hernia, without obstruction or gangrene
- K40.3 Unilateral inguinal hernia, with obstruction, without gangrene
- K40.4 Unilateral inguinal hernia, with gangrene
- K40.9 Unilateral inguinal hernia, without obstruction or gangrene
Both the inguinal and femoral hernia categories (K40 and K41) are subdivided in this manner to the next level by laterality and presentation.
For these two types of hernia, a further subclassification then provides the status as recurrent or not specified as recurrent:
- K40.30 Unilateral inguinal hernia,
- with obstruction, without gangrene, not specified as recurrent
- K40.31 Unilateral inguinal hernia, with obstruction, without gangrene, recurrent
- K43.0 Incisional hernia with obstruction, without gangrene
- K43.5 Parastomal hernia without obstruction or gangrene
- K43.6 Other and unspecified ventral hernia with gangrene
Epigastric, hypogastric, midline, spigelian, and subxiphoid hernias are all included under other and unspecified ventral hernias.
Acquired hiatal, esophageal, sliding, and paraesophageal hernias are included under diaphragmatic hernia, category K44, remembering that congenital diaphragmatic hernias are reported with Q79.0 and congenital hiatal hernias are coded to Q40.1 in the chapter for conditions arising in the perinatal period.
No additional codes needed
As a last point for discussing coding hernias in ICD-10-CM, it is important to note that there are no additional digits to be added to hernia codes in ICD-10-CM in order to complete the code description. All possible code combinations are provided in a complete code description for each code.