CPT 01630 is the workhorse anesthesia code for shoulder surgery. It applies when the anesthesiologist provides anesthesia for an open or surgical arthroscopic procedure performed at any of the following anatomical sites: humeral head and neck, SC joint, AC joint, or glenohumeral joint. The NOS designation means 01630 applies whenever the underlying procedure does not qualify for a more specific code in the 01630 family (01634, 01636, or 01638).
Common procedures that map to 01630 include arthroscopic rotator cuff repair (partial or full thickness), Bankart repair and labral reconstruction, SLAP repair, subacromial decompression and acromioplasty, AC joint resection (distal clavicle excision), SC joint procedures, shoulder arthroscopy with surgical debridement or chondroplasty, and open shoulder stabilization procedures.
Code selection follows the surgeon, not the anesthetic technique. The operative report drives code selection. Whether the anesthesiologist uses general anesthesia, total intravenous anesthesia, or regional anesthesia with sedation, 01630 remains the correct code when the surgical procedure falls within scope. The type of anesthesia delivered is captured by modifier, not by code.
Scope boundaries: 01630 covers open and surgical arthroscopic procedures at the shoulder joint complex. Procedures confined to soft tissues, tendons, bursae, or nerves of the shoulder and axilla without joint entry are more appropriately reported with 01610. Diagnostic arthroscopy with no surgical intervention maps to 01622.
Time units: CMS requires anesthesia time to be reported in minutes on the claim form (field 24G); the MAC converts to units internally [1]. Anesthesia time begins when the anesthesiologist starts preparing the patient for induction in the operating room and ends when the anesthesiologist is no longer in personal attendance. Time spent in the PACU after the anesthesiologist transfers care does not count. Time from a preoperative hold area also does not count unless the anesthesiologist is actively attending to the patient in the operating room suite.
| Code | Description | When to Use Instead |
|---|---|---|
| 01630 | Anesthesia, open or surgical arthroscopic shoulder procedures, NOS | Rotator cuff repair, Bankart repair, SLAP repair, AC joint resection, subacromial decompression, and all other surgical shoulder arthroscopy or open procedures not meeting a more specific code |
| 01610 | Anesthesia, procedures on nerves, muscles, tendons, fascia, and bursae of shoulder and axilla | Procedures confined to soft tissue without joint entry (e.g., bursectomy without arthroscopy, axillary nerve decompression) |
| 01620 | Anesthesia, closed procedures on shoulder joint complex | Closed manipulation under anesthesia of the shoulder without arthroscopy |
| 01622 | Anesthesia, diagnostic arthroscopic procedures of shoulder joint | Diagnostic arthroscopy only; no surgical intervention performed during the case |
| 01638 | Anesthesia, total shoulder replacement | Total or reverse total shoulder arthroplasty; use this code, not 01630, for any shoulder arthroplasty |
| 01634 | Anesthesia, shoulder disarticulation | Amputation at the level of the shoulder joint |
| 01636 | Anesthesia, interthoracoscapular forequarter amputation | Radical amputation including the shoulder girdle and clavicle |
The most consequential differentiation is between 01630 and 01638. Total shoulder replacement (including reverse total shoulder arthroplasty) has its own code with distinct base units; billing 01630 NOS when a total shoulder replacement was performed consistently results in underpayment.
The second critical distinction is between 01630 and 01622. When a surgeon schedules a diagnostic shoulder arthroscopy and converts to a surgical procedure intraoperatively, the correct code for the entire case is 01630. The final nature of the procedure determines the anesthesia code, not the original surgical plan.
flowchart TD
A[Shoulder procedure?] --> B{Open or surgical arthroscopic?}
B -- No: closed only --> C[01620]
B -- Yes --> D{Specific procedure type?}
D -- Total shoulder replacement --> E[01638]
D -- Shoulder disarticulation --> F[01634]
D -- Forequarter amputation --> G[01636]
D -- Diagnostic arthroscopy only --> H[01622]
D -- Rotator cuff, labral, AC joint, NOS --> I[01630]
A -- Soft tissue or nerve only --> J[01610]
Provider role modifiers are required on every anesthesia claim. Select based on the provider arrangement [1]:
| Modifier | Who Bills | Situation | Medicare Payment |
|---|---|---|---|
| AA | Anesthesiologist | Personally performed, no CRNA or AA involvement | 100% |
| QK | Anesthesiologist | Medically directing 2 to 4 concurrent cases | 50% |
| QY | Anesthesiologist | Medically directing 1 CRNA (1 to 1 direction) | 50% |
| AD | Anesthesiologist | Supervising more than 4 concurrent cases | Capped at 3 base units |
| QX | CRNA | Under physician medical direction | 50% |
| QZ | CRNA | Independent, no physician direction | 100% of CRNA allowed amount |
| GC | Anesthesiologist | Teaching physician directing a resident | Special teaching rules apply |
Physical status modifiers (P1 through P5) are appended to the anesthesia CPT code and reflect the patient's systemic condition per the ASA Physical Status Classification System [2]. Under Medicare, these modifiers carry no additional payment units. Commercial payers vary; many add 1 unit for P3, 2 units for P4, and 3 units for P5.
Qualifying circumstances are add-on codes billed alongside 01630 when applicable:
These are add-on codes and cannot be billed without a base anesthesia code such as 01630.
Add-on code 0887T: CPT 0887T (end-tidal control of inhaled anesthetic agents and oxygen to assist anesthesia care delivery, added 2024) is listed separately in addition to 01630 when utilized. Per CPT guidelines, 0887T is used in conjunction with codes 00100 through 01999 [3].
Separately reportable nerve blocks: An interscalene nerve block performed for postoperative pain management is separately billable when it is a distinct service from the surgical anesthesia, documented separately in the medical record, and not the primary anesthetic technique. If the interscalene block IS the primary anesthetic technique, billing both the nerve block and 01630 constitutes unbundling.
Global days: 01630 carries a global days indicator of XXX, meaning the global surgery concept does not apply to anesthesia codes. Preoperative and postoperative anesthesia evaluations on the day of surgery are included in the anesthesia service and are not separately billable [1].
Pre-anesthesia evaluation: Must be performed and documented before the procedure begins, including patient history, relevant comorbidities, physical exam, airway assessment, and ASA physical status assignment with supporting clinical rationale. This is the basis for physical status modifier selection [1].
Intraoperative anesthesia record: Must document continuous monitoring data (blood pressure, heart rate, SpO2, EtCO2, temperature at appropriate intervals), all drugs administered with dose, route, and time, and specifically, documented anesthesia start and stop times in minutes. Patient positioning must also be recorded; for beach chair position cases, documentation of cerebral perfusion monitoring protocols is advisable.
Post-anesthesia evaluation: Must be completed before patient discharge from post-anesthesia care. Together with the preanesthesia evaluation, this frames the medical necessity documentation for the case.
Medical direction conditions: When billing QK or QY, the record must demonstrate all 7 CMS medical direction conditions were satisfied: preanesthesia examination and evaluation, prescription of the anesthesia plan, personal participation in the most demanding procedures including induction and emergence, monitoring of the case at frequent intervals, remaining immediately available, postanesthesia evaluation, and documentation of the conditions met [1]. OIG has identified medical direction compliance as a high-risk billing area.
Audit red flags specific to 01630:
Medicare
Anesthesia payment follows the formula: (Base Units + Time Units + Qualifying Circumstance Units) x Anesthesia Conversion Factor [1]. The 2025 anesthesia conversion factor is $21.1473 per unit, per the CY2025 MPFS Final Rule [4]. This is a separate, lower conversion factor than the general MPFS conversion factor of $32.3465.
There is no national coverage determination (NCD) specific to anesthesia for shoulder surgery. Coverage for 01630 derives from the coverage determination for the underlying surgical procedure; if the shoulder surgery is denied as not medically necessary, the anesthesia claim will be denied on the same basis.
CMS requires anesthesia time reported in minutes on the claim form (field 24G); the MAC converts to units. In states where the governor has opted out of the Medicare CRNA supervision requirement, CRNAs may bill independently using modifier QZ without physician direction.
Commercial Payers
Most commercial payers follow the base unit plus time formula but may diverge on physical status unit additions (P3 through P5 may carry payment units; verify per contract), conversion factor values (typically higher than the Medicare rate), and qualifying circumstance recognition (some payers bundle 99100 or do not separately recognize 99116). Prior authorization for the underlying surgical procedure transitively affects anesthesia coverage; confirm the surgical authorization covers the anesthesia service as well.
Missing provider role modifier
Without AA, QK, QX, QY, QZ, AD, or GC, the claim is technically incomplete. Most payers auto-deny before clinical review. Prevention: build a hard edit in the charge capture or claim scrubbing system that flags 01630 without a provider role modifier before submission.
Wrong code in the 01630 family
Billing 01630 when the underlying procedure is a total shoulder replacement (correct code: 01638) is among the most common underpayment errors for shoulder anesthesia. Root cause: charge capture defaults to the NOS code without a procedure-specific lookup. Prevention: require the operative note to be reviewed against the full 01630 family before the anesthesia code is finalized; flag the combination of 01630 with total shoulder arthroplasty ICD diagnosis codes for manual review.
Undocumented or ambiguous anesthesia time
Time units calculated from a duration note ("case lasted 90 minutes") rather than specific start and stop times are subject to audit adjustment. Medicare specifically requires absolute start and stop times in the record [1]. Prevention: implement a required field for start time and end time (not elapsed time) in the electronic anesthesia record.
Medical direction conditions not documented
Billing QK or QY without evidence that all 7 CMS conditions were met; auditors specifically examine whether the anesthesiologist was present at induction and emergence and remained immediately available. Prevention: include a structured medical direction attestation in the anesthesia record for every concurrent case with specific time entries confirming presence at induction and emergence.
Qualifying circumstance billed without supporting documentation
Billing 99100 (extreme age) or 99116 (controlled hypotension) without corresponding documentation results in recoupment on audit. Prevention: add a structured field in the anesthesia record requiring free-text justification whenever a qualifying circumstance code is selected.
Scenario: A 56-year-old female with controlled hypertension (ASA P2) undergoes elective arthroscopic rotator cuff repair with subacromial decompression. The anesthesiologist personally provides general anesthesia for 75 documented minutes.
Correct coding: 01630 with AA and P2
Why: The procedure is a surgical arthroscopic shoulder procedure within the NOS category; no more specific 01630-family code applies. AA reflects personal performance. At 2025 Medicare rates: (5 base + 5 time units) x $21.1473 = $211.47 allowed [4].
Scenario: A diagnostic shoulder arthroscopy is scheduled. Intraoperatively, the surgeon identifies and repairs a SLAP tear. The anesthesia record was pre-labeled for a diagnostic case.
Correct coding: 01630 with AA (not 01622)
Why: When a diagnostic arthroscopy converts to a surgical procedure, the surgical anesthesia code covers the entire case. The final nature of the procedure determines the code, regardless of the original surgical plan.
Scenario: A 74-year-old male with COPD (ASA P3) presents emergently with a proximal humerus fracture-dislocation requiring urgent open reduction and internal fixation. Anesthesia time is 120 minutes.
Correct coding: 01630 with AA, P3, 99100, and 99140
Why: The patient is over 70 (99100, adds 5 units) and the case is emergent (99140, adds 5 units). Under Medicare, P3 is informational and adds no units. Estimated Medicare allowable at 2025 rates: (5 base + 8 time units + 10 qualifying circumstance units) x $21.1473 = 23 x $21.1473 = $486.39 [4].
Scenario: An anesthesiologist is medically directing 3 CRNAs simultaneously, each performing anesthesia for a separate shoulder arthroscopy case. One CRNA handles an arthroscopic Bankart repair (01630).
Correct coding: Anesthesiologist bills 01630 with QK; CRNA bills 01630 with QX.
Why: Medical direction of 2 to 4 concurrent cases is reported with QK by the physician and QX by the CRNA. Each claim is paid at 50% of the allowed amount. The anesthesiologist's record must document all 7 CMS medical direction conditions for each concurrent case [1].
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