CPT code 01160: Anesthesia for closed pelvic joint procedures

Key Takeaways

CPT code 01160 describes anesthesia for closed procedures involving the symphysis pubis or sacroiliac joint, sitting within the Anesthesia for Procedures on the Pelvis (Except Hip) section of the CPT code set.

The code carries 4 base units per the ASA Relative Value Guide; reimbursement is calculated as (base units + time units + qualifying circumstance units) multiplied by an anesthesia conversion factor that varies by payer and locality.

Modifiers AA, QX, QY, QZ, and QK are the most commonly applied modifiers; selecting the wrong medical direction modifier is a leading cause of claim denials for 01160.

Pabau’s claims management software helps surgical and anesthesia practices track modifier rules, attach supporting documentation, and reduce denials at submission.

Pelvic anesthesia claims are among the most modifier-sensitive in the CPT code set. A single wrong modifier on CPT code 01160 can trigger an automatic denial, and incomplete anesthesia time documentation compounds the problem. Most billing errors on this code trace back to the same two gaps: misapplied medical direction modifiers and missing operative start/stop timestamps.

This reference covers the complete billing picture for CPT code 01160: its official description, base unit assignment, time unit calculation, applicable modifiers, paired ICD-10 diagnosis codes, reimbursement methodology, and the documentation requirements that keep claims clean.

CPT code 01160: description and clinical context

CPT code 01160 is defined by the American Medical Association (AMA) as: Anesthesia for closed procedures involving symphysis pubis or sacroiliac joint. It sits within the broader section “Anesthesia for Procedures on the Pelvis (Except Hip)” in the claims management software workflow most surgical practices follow when processing pelvic procedure cases.

Two anatomical landmarks define this code’s scope:

• Symphysis pubis: The cartilaginous joint connecting the two pubic bones at the front of the pelvis. Closed procedures here include manipulation under anesthesia, fluoroscopically guided injections, and reduction of pubic symphysis diastasis.
• Sacroiliac (SI) joint: The joint between the sacrum and the ilium. Closed procedures include SI joint injections, arthrodesis (where no open incision is made), and closed manipulation.

The critical word in the descriptor is closed. Once a surgeon makes an incision to directly access either joint, the procedure moves out of 01160 territory and into CPT 01170 (open procedures) or CPT 01173 (open repair of fracture disruption of pelvis). Billing 01160 for an open case is an upcoding risk with potential audit consequences.

Where 01160 fits in the anesthesia CPT hierarchy

Understanding the neighboring codes prevents misassignment. The pelvis (except hip) section runs sequentially, with each code mapped to a specific procedure type and anatomical scope:

Base unit values shown reflect the Arizona ICA fee schedule (2020-2021) and are provided for reference; confirm current values against the AMA’s annual CPT coding resources and your payer’s current contract before billing. The HIPAA compliance documentation requirements for anesthesia records apply equally across all codes in this section.

Base units, time units, and reimbursement calculation for CPT code 01160

Anesthesia reimbursement follows a formula that is distinct from every other section of the CPT code set. Unlike surgical codes paid on a flat RVU basis, anesthesia payment scales with the actual time the anesthesia provider spends with the patient.

The standard formula, recognized by CMS’s Physician Fee Schedule, is:

For a typical 45-minute closed SI joint injection under anesthesia, the claim totals 7 units before any qualifying circumstances. Exact dollar reimbursement depends on the payer’s contract and geographic locality. Use the FastRVU 2026 RVU lookup tool to verify current Medicare RVU values for your region.

Anesthesia time: start, stop, and documentation

Anesthesia time begins when the anesthesia provider starts preparing the patient for induction in the operating room (or equivalent area) and ends when the provider is no longer in personal attendance. Both timestamps must appear in the surgical practice management software record or paper anesthesia record. Missing or inconsistent timestamps are the most common reason payers request medical records after an anesthesia claim is submitted.

Most commercial payers and Medicare follow the 15-minute per unit convention. Some workers’ compensation carriers use 10-minute increments. Always check your payer contracts before calculating units.

Modifiers for CPT code 01160

Modifier selection determines whether a claim pays at the full rate or triggers a review. Four categories of modifiers apply to CPT code 01160: provider status, medical direction, physical status, and qualifying circumstances.

Provider status and medical direction modifiers

These modifiers tell the payer who performed the anesthesia and under what supervisory arrangement:

• AA: Anesthesia services performed personally by an anesthesiologist. Full payment applies. No concurrent cases.
• QK: Medical direction by a physician of two, three, or four concurrent anesthesia procedures. Payment is typically 50% of the AA rate per case.
• QX: CRNA service under the medical direction of a physician. Paired with QK on the physician’s claim.
• QY: Medical direction of one CRNA by a physician. Applies when the anesthesiologist directs a single CRNA.
• QZ: CRNA service without medical direction of a physician. Full CRNA payment; the supervising physician does not bill.
• AD: Supervision of more than four concurrent anesthesia procedures by a physician. Reimbursement capped at three base units per procedure.

Matching QK and QX on the respective physician and CRNA claims is mandatory. A claim with QX but no corresponding QK from the directing physician will generate a mismatch edit. Use digital intake and consent forms to pre-capture anesthesia provider assignments before the case date, reducing day-of documentation gaps.

Physical status modifiers

Physical status (P) modifiers add units to reflect patient health complexity. They are required by most payers for anesthesia claims:

• P1: Normal healthy patient (0 additional units)
• P2: Mild systemic disease (0 additional units for most payers)
• P3: Severe systemic disease (+1 unit under ASA guidelines)
• P4: Severe systemic disease that is a constant threat to life (+2 units)
• P5: Moribund patient unlikely to survive without surgery (+3 units)
• P6: Brain-dead patient for organ donation purposes (used in specific circumstances)

Not all payers reimburse for physical status units. Medicare, for example, does not pay additional units for P3-P5. Commercial payers vary. Check your payer contracts and use the AAPC Codify CPT lookup to confirm current payer-specific policies before reporting physical status units.

Qualifying circumstances add-on codes