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Official Description

Transmastoid antrotomy (simple mastoidectomy)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The procedure described by CPT® Code 69501 refers to a transmastoid antrotomy, commonly known as a simple mastoidectomy. This surgical intervention involves accessing the mastoid antrum, which is a cavity located within the petrous portion of the temporal bone. The mastoid antrum plays a crucial role in the anatomy of the ear, as it is situated posteriorly to the middle ear and communicates with the mastoid air cells. The anterior aspect of the antrum connects to the middle ear structures, making it significant in the context of ear infections and related conditions. A simple mastoidectomy is primarily indicated for the treatment of acute infections, where the goal is to alleviate symptoms and prevent further complications. During the procedure, the surgeon approaches the mastoid antrum through the mastoid air cells, allowing for direct access to the infected area. Once the antrum is exposed, the surgeon meticulously removes any purulent matter, debris, and infected tissue to promote healing and restore normal function. In some cases, a drain may be placed within the antrum to facilitate ongoing drainage of any residual fluid or infection, ensuring that the area remains clear and reducing the risk of postoperative complications.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The transmastoid antrotomy, or simple mastoidectomy, is performed for specific indications related to ear health. The following conditions are explicitly recognized as reasons for undertaking this procedure:

  • Acute Infection The primary indication for a simple mastoidectomy is the presence of an acute infection in the mastoid area, which may lead to complications if not addressed promptly.

2. Procedure

The procedure of transmastoid antrotomy involves several critical steps to ensure effective treatment of the infection. Each step is designed to provide the surgeon with the necessary access and visibility to the affected area.

  • Step 1: Accessing the Mastoid Air Cells The surgeon begins by making an incision behind the ear to access the mastoid air cells. This incision allows for the removal of bone and tissue to create a pathway to the mastoid antrum.
  • Step 2: Exposing the Mastoid Antrum Once the mastoid air cells are accessed, the surgeon carefully removes additional bone to expose the mastoid antrum. This step is crucial for visualizing the infected area and determining the extent of the infection.
  • Step 3: Removal of Infected Tissue After exposing the antrum, the surgeon proceeds to remove any purulent matter, debris, and infected tissue. This debridement is essential for eliminating the source of infection and promoting healing.
  • Step 4: Placement of Drain In some cases, a drain may be placed within the antrum to facilitate continued drainage of any residual fluid or infection. This helps to prevent the accumulation of fluids that could lead to further complications.

3. Post-Procedure

Following the transmastoid antrotomy, patients typically require monitoring for any signs of complications. Post-procedure care may include pain management, instructions for wound care, and follow-up appointments to assess healing. The placement of a drain, if utilized, will also necessitate specific care to ensure proper function and prevent infection. Patients are advised to report any unusual symptoms, such as increased pain, fever, or drainage from the surgical site, to their healthcare provider promptly. Recovery time may vary depending on the individual and the extent of the procedure, but most patients can expect a gradual return to normal activities as healing progresses.

Short Descr MASTOIDECTOMY
Medium Descr TRANSMASTOID ANTROTOMY
Long Descr Transmastoid antrotomy (simple mastoidectomy)
Status Code Active Code
Global Days 090 - Major Surgery
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 2 - Standard payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 1 - 150% payment adjustment for bilateral procedures applies.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 1 - Statutory payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Hospital Part B services paid through a comprehensive APC
ASC Payment Indicator Surgical procedure on ASC list in CY 2007; payment based on OPPS relative payment weight.
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P5E - Ambulatory procedures - other
MUE 1
CCS Clinical Classification 24 - Mastoidectomy
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
52 Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use).
58 Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
80 Assistant surgeon: surgical assistant services may be identified by adding modifier 80 to the usual procedure number(s).
GC This service has been performed in part by a resident under the direction of a teaching physician
GW Service not related to the hospice patient's terminal condition
LT Left side (used to identify procedures performed on the left side of the body)
RT Right side (used to identify procedures performed on the right side of the body)
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
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