Inpatient Surgical Site of Service
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Medicare-only policy governing when selected surgical procedures (not on the CMS Inpatient Only list) require inpatient admission versus outpatient/ASC setting; applies to Providence Medicare lines and affects providers requesting inpatient admission for covered surgical procedures.
No material clinical or coverage changes in this revision.
Inpatient Admission and Site‑of‑Service Appropriateness
Inpatient admission / site-of-service appropriateness
Covered inpatient admission when ALL of the following are met or applicable:
Medicare requirement
CMS IPO governs; policy does not apply to IPO services
Documentation must justify inpatient setting; the Plan will review medical records
Plan will review records to determine reasonableness
Plan may apply its objective, evidence-based criteria consistent with Medicare guidance
This policy does not apply to services on the CMS Inpatient Only (IPO) list. Procedures on the IPO list are governed by CMS inpatient‑only rules (Addendum E) and, when listed, are generally considered medically appropriate for inpatient admission without additional Plan review. For the most current IPO listings and guidance, refer to the CMS Hospital Outpatient Prospective Payment System Addendum E resources noted by CMS.
All unlisted codes submitted for services addressed in this policy are reviewed at the claim level. If an unlisted code is submitted for a service that is not covered by this policy, the claim will be denied as not covered. To avoid post‑service denial, providers should prior authorize unlisted codes when the service might be covered.
When a procedure appears on the CMS ASC‑covered procedures list or is not found on either the CMS IPO or ASC lists, inpatient admission is not presumed. For procedures on the ASC list, CMS has determined they generally do not require routine overnight monitoring; therefore an inpatient stay must be supported by clear clinical documentation demonstrating the need for inpatient level of care. Similarly, for procedures not listed on either CMS list, the medical record must document the clinical rationale for inpatient admission. Lack of documentation supporting inpatient level of care may render the admission not medically necessary.
Codes, Lists, and Benchmarks in Scope
| No codes listed |
| No codes listed |
| No codes listed |
| 21243 | Arthroplasty, temporomandibular joint, with prosthetic joint replacement. |
| 24360 | Arthroplasty, elbow; with membrane (eg, fascial). |
| 24366 | Arthroplasty, radial head; with implant. |
| 25332 | Arthroplasty, wrist, with or without interposition, with or without external or internal fixation. |
| 25442 | Arthroplasty with prosthetic replacement; distal ulna. |
| 25446 | Arthroplasty with prosthetic replacement; distal radius and partial or entire carpus (total wrist). |
| 25447 | Arthroplasty, intercarpal or carpometacarpal joints; interposition. |
| 25448 | Arthroplasty, intercarpal or carpometacarpal joints; suspension, including transfer. |
| 26531 | Arthroplasty, metacarpophalangeal joint; with prosthetic implant, each joint. |
| 26535 | Arthroplasty, interphalangeal joint; each joint. |
| 23470 | Arthroplasty, glenohumeral joint; hemiarthroplasty. |
| 23472 | Arthroplasty, glenohumeral joint; total shoulder (glenoid and proximal humeral replacement). |
| 27130 | Arthroplasty, acetabular and proximal femoral prosthetic replacement (total hip arthroplasty), with or without autograft or allograft. |
| 27447 | Arthroplasty, knee, condyle and plateau; medial AND lateral compartments with or without patella resurfacing (total knee arthroplasty). |
| 27702 | Arthroplasty, ankle; with implant (total ankle). |
| 22532 | Arthrodesis, lateral extracavitary technique, including minimal discectomy to prepare interspace (other than for decompression); thoracic. |
| 22533 | Arthrodesis, lateral extracavitary technique, including minimal discectomy to prepare interspace (other than for decompression); lumbar. |
| 22548 | Arthrodesis, anterior transoral or extraoral technique, clivus-C1-C2 (atlas-axis), with or without excision of odontoid process. |
| 22554 | Arthrodesis, anterior interbody technique, including minimal discectomy to prepare interspace (other than for decompression); cervical below C2. |
| 22556 | Arthrodesis, anterior interbody technique, including minimal discectomy to prepare interspace (other than for decompression); thoracic. |
| 22558 | Arthrodesis, anterior interbody technique, including minimal discectomy to prepare interspace (other than for decompression); lumbar. |
| 22612 | Arthrodesis, posterior or posterolateral technique, single interspace; lumbar (with lateral transverse technique, when performed). |
| 22857 | Total disc arthroplasty (artificial disc), anterior approach, including discectomy with end plate preparation (includes osteophytectomy for nerve root or spinal cord decompression and microdissection); single interspace, cervical. |
| 22858 | Total disc arthroplasty (artificial disc), anterior approach, including discectomy to prepare interspace (other than for decompression), single interspace, lumbar. |
| 22861 | Revision including replacement of total disc arthroplasty (artificial disc), anterior approach, single interspace; cervical. |
Prior Authorization, Documentation, and Denial Risk
Prior authorization / medical necessity review when inpatient admission is anticipated
For services that are eligible to be performed outpatient (i.e., not on the CMS Inpatient Only list), if an inpatient admission is anticipated the Plan will review the clinical documentation to support the medical need for inpatient place of service; the review will consider Medicare factors including the two‑midnight benchmark and may reference screening instruments (InterQual®/MCG™) though their use is not required.
- Clinical documentation must justify inpatient level of care when procedure is not on the CMS IPO list.
- Expectations about crossing two midnights will be evaluated based on clinical information at time of admission.
- Screening tools (InterQual®/MCG™) may be used but are not required; clinical judgment is mandatory.
Prior authorization required for select procedures (POS 21) and some procedures regardless of POS
Certain procedures require prior authorization when billed with place of service code 21 (inpatient); other procedures may require prior authorization regardless of place of service to review general medical necessity and inpatient appropriateness. See the Providence Health Plan Combined Prior Authorization List for specifics.
- Codes that only require prior authorization when billed POS 21 will not require prior authorization at other places of service.
- Some procedures require prior authorization at any POS to evaluate medical necessity and inpatient appropriateness.
Step therapy not applicable
No step therapy requirements are stated in this portion of the document.
Required documentation for medical necessity review
Submit complete medical records to support inpatient medical necessity reviews, including history; physical examination (including patient weight and co-morbidities); surgical plan; and the American Society of Anesthesiologists Physical Classification (ASA-PS) score. Missing items may delay review or affect the decision outcome.
- History
- Physical exam including patient weight and co-morbidities
- Surgical plan
- ASA-PS score
Documentation & prior authorization guidance (POS 21 and unlisted codes)
Reiterate: certain procedures only require prior authorization when billed POS 21 (inpatient); other procedures may require prior authorization regardless of POS. Unlisted codes that may be covered should be prior authorized to avoid post-service denial; consult the Providence Health Plan Combined Prior Authorization List.
- Codes billed POS 21 may trigger prior authorization even if same code at other POS does not.
- All unlisted codes are reviewed for medical necessity; prior authorization is recommended for potentially covered unlisted codes to avoid post-service denial.
Denial risk for unsupported inpatient admissions
Inpatient admission requests for procedures not on the CMS Inpatient Only list will be reviewed for medical necessity; if clinical documentation does not support the need for inpatient setting the request may be denied.
- Inpatient admission for procedures on the ASC list or not on either list will be considered not medically necessary if documentation does not justify inpatient care.
Denial risk for unlisted codes submitted for non-covered services
If an unlisted code is submitted for non-covered services addressed in this policy it will be denied as not covered; unlisted codes for potentially covered services should be prior authorized to avoid post-service denial.
- All unlisted codes are reviewed for medical necessity, correct coding, and pricing at the claim level.
- Prior authorization is recommended for unlisted codes that may be covered.
Policy Background and Scope
CMS maintains the Inpatient Only (IPO) list to identify HCPCS/CPT procedures that typically require inpatient care because of safety concerns, the typical condition of patients, or the need for at least 24 hours of postoperative monitoring. In contrast, procedures on the CMS ASC‑covered surgical procedures list have been determined by CMS to pose no significant safety risk when performed in Ambulatory Surgical Centers and generally do not require an overnight stay. Because IPO procedures are deemed to pose greater safety risk, they are eligible for Medicare coverage only when rendered in an inpatient setting; ASC procedures are generally outpatient‑appropriate unless the medical record documents otherwise. The Plan therefore uses these CMS lists, along with Medicare medical necessity principles (including the two‑midnight benchmark), to guide site‑of‑service determinations for the procedures in scope.
Key Definitions and External Lists
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