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CPT 23929: Shoulder Unlisted Procedure

CPT code 23929 is an unlisted procedure code for shoulder surgery used when no specific CPT descriptor applies. Nationally, unlisted procedure codes like 23929 matter because they require supplemental documentation to justify medical necessity and detail the service provided, influencing claims processing, prior authorization, and payment determinations. This code is relevant across hospital outpatient departments and ambulatory surgical centers where atypical or novel shoulder procedures occur.

Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of how 23929 is categorized, typical clinical and billing contexts where it is used, and what documentation expectations generally apply for unlisted shoulder procedures. The publication outlines benchmarking considerations, common payer policy themes, and clinical context for coding selection and claim submission.

The content is designed for billing managers, surgical coders, compliance officers, and policy analysts seeking a national-level reference for 23929. Data not provided in the input (such as specific payer edit rules or associated ICD-10 diagnoses) are noted where relevant.

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Billing Code Overview

CPT code 23929 is an unlisted procedure code used to report a shoulder surgical procedure that does not have a specific CPT code. It is intended for reporting unique or atypical shoulder operations that fall outside established, descriptive shoulder procedure codes.

Service type: Surgical — shoulder procedure (unlisted)

Typical site of service: Hospital outpatient department or ambulatory surgical center

Data not available in the input.

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CPT 23929: Shoulder Unlisted Procedure

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Get alerted when payer policies referencing 23929 are released or updated.

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Billing Code Overview

Service type: Surgical — shoulder procedure (unlisted)

Typical site of service: Hospital outpatient department or ambulatory surgical center

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 58-year-old manual laborer presents with persistent shoulder pain and functional limitation after prior treatments for a complex rotator cuff tear and post-traumatic glenohumeral instability. Prior standard CPT codes for rotator cuff repair, labral repair, and arthroscopic debridement do not accurately describe the definitive procedure performed: an open, combined reconstruction of multiple shoulder structures during the same operative session that does not map to a single existing shoulder CPT. The surgeon documents reconstruction of the rotator cuff footprint with a biologic graft, capsular plication for multidirectional instability, and contouring of a complex proximal humeral deformity. The procedure is billed using 23929 to capture a shoulder procedure not otherwise specified.

Typical clinical workflow:

Preoperative evaluation in clinic with imaging (radiographs, MRI) confirming complex multi-structure pathology.
Preauthorization may be obtained from payors such as Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, BUCA, and Medicare when indicated for an unlisted procedure.
On the day of surgery, operative note documents all components, estimated operative time, and rationale for use of the unlisted code 23929 with clear linkage to diagnoses and descriptions of the specific steps performed.
Coding staff prepare a detailed operative report and an itemized list of supplies, attach relevant comparable CPT codes if available, and submit supporting documentation to payors to justify medical necessity and allow appropriate reimbursement review.
Postoperative visits document recovery, complications if any, and rehabilitation plans tied to the initial diagnosis codes and the complex shoulder reconstruction performed.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when work required is substantially greater than usual for `23929` and documentation supports unusual time, technical difficulty, or severity.
`26`	Professional component	Use when reporting only the physician professional component separate from technical services, if applicable in reporting ancillary services tied to the procedure.
`50`	Bilateral procedure	Use when identical shoulder procedures on both sides are performed during the same operative session and payer accepts bilateral reporting for an unlisted shoulder code.
`51`	Multiple procedures	Use when `23929` is reported on the same day with other distinct procedures; some payors require modifier `51` to indicate multiple-procedure pricing.
`52`	Reduced services	Use when the service is partially reduced or abandoned and documentation explains the reduction.
`53`	Discontinued procedure	Use when procedure is started but discontinued due to extenuating circumstances; operative note must explain reason.
`59`	Distinct procedural service	Use to indicate a separate, distinct procedure was performed on the same day that is not normally reported together.
`62`	Two surgeons	Use when two surgeons work together as primary surgeons performing distinct portions of the complex shoulder reconstruction.
`78`	Return to operating room for related procedure by same physician	Use when a related procedure on the same shoulder is performed during the global period due to a complication.
`79`	Unrelated procedure or service by same physician during global period	Use when an unrelated procedure is performed during the global period.
`80`	Assistant surgeon	Use to indicate assistant surgeon services during the procedure when permitted.
`81`	Minimum assistant surgeon	Use when a minimal assistant surgeon provided limited assistance and payer accepts `81`.
`82`	Assistant surgeon when qualified resident unavailable	Use when an assistant is required because a qualified resident is unavailable.
`59`	Distinct procedural service (alternate)	Use when another procedure performed same day needs separation by site or service; some payors prefer modifier `59` over others.

Taxonomy Code	Specialty	Notes
207X00000X	Orthopaedic Surgery	Primary specialty performing complex shoulder reconstructions including open and arthroscopic procedures.
2080P0206X	Hand Surgery (Orthopedic)	Orthopedic hand/upper-extremity surgeons who manage complex shoulder/upper extremity reconstruction.
207L00000X	Sports Medicine (Orthopedic)	Specialists focusing on shoulder instability and rotator cuff pathology who may perform combined procedures.
2084P0800X	Shoulder and Elbow Surgery	Subspecialists concentrating on advanced reconstructive shoulder procedures.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`M75.121`	Complete rotator cuff tear or rupture of right shoulder, not specified as traumatic	Rotator cuff tears frequently necessitate complex repair or reconstruction procedures captured by an unlisted shoulder code when combined or atypical techniques are used.
`M75.122`	Complete rotator cuff tear or rupture of left shoulder, not specified as traumatic	See above for contralateral presentations requiring similar complex reconstruction.
`M24.211`	Recurrent dislocation, right shoulder	Chronic instability with recurrent dislocations may require capsular plication or reconstructive procedures included in an unlisted shoulder code.
`M24.212`	Recurrent dislocation, left shoulder	Same clinical relevance for the left shoulder.
`M75.51`	Biceps tendinitis, right shoulder	Biceps pathology is commonly addressed during shoulder reconstructions and can be part of the unlisted procedure.
`M75.52`	Biceps tendinitis, left shoulder	As above for left shoulder.
`M19.011`	Primary osteoarthritis, right shoulder	Advanced degenerative change may require debridement, contouring, or reconstructive techniques captured by `23929`.
`S43.431A`	Superior glenohumeral ligament sprain of right shoulder, initial encounter	Acute complex traumatic injuries with multi-structure damage may be treated with combined procedures billed with an unlisted shoulder code.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`23410`	Repair of ruptured musculotendinous cuff (eg, rotator cuff), open; acute	May represent a primary rotator cuff repair component when a specific repair code is available; used as a comparable code when parts of the open repair are performed.
`29827`	Arthroscopy, shoulder, surgical; with rotator cuff repair	Performed arthroscopically for rotator cuff repair components; may be performed before or instead of an open component—often referenced when mixed arthroscopic and open techniques are used.
`23465`	Tenodesis of long tendon of biceps, open; with tenodesis	Performed when concurrent biceps pathology is addressed during complex shoulder reconstruction.
`23130`	Excision, clavicle; distal end	Performed when distal clavicle resection is required as part of a more complex shoulder procedure to address acromioclavicular arthritis or impingement.
`29999`	Unlisted procedure, arthroscopy	Used for arthroscopic procedures without a specific code; may be submitted for arthroscopic components not otherwise described by established codes and can be billed alongside or compared to `23929`.

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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Clinical & Coding Specifications

Clinical Context

Typical clinical workflow:

Preoperative evaluation in clinic with imaging (radiographs, MRI) confirming complex multi-structure pathology.
Preauthorization may be obtained from payors such as Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, BUCA, and Medicare when indicated for an unlisted procedure.
On the day of surgery, operative note documents all components, estimated operative time, and rationale for use of the unlisted code 23929 with clear linkage to diagnoses and descriptions of the specific steps performed.
Coding staff prepare a detailed operative report and an itemized list of supplies, attach relevant comparable CPT codes if available, and submit supporting documentation to payors to justify medical necessity and allow appropriate reimbursement review.
Postoperative visits document recovery, complications if any, and rehabilitation plans tied to the initial diagnosis codes and the complex shoulder reconstruction performed.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when work required is substantially greater than usual for `23929` and documentation supports unusual time, technical difficulty, or severity.
`26`	Professional component	Use when reporting only the physician professional component separate from technical services, if applicable in reporting ancillary services tied to the procedure.
`50`	Bilateral procedure	Use when identical shoulder procedures on both sides are performed during the same operative session and payer accepts bilateral reporting for an unlisted shoulder code.
`51`	Multiple procedures	Use when `23929` is reported on the same day with other distinct procedures; some payors require modifier `51` to indicate multiple-procedure pricing.
`52`	Reduced services	Use when the service is partially reduced or abandoned and documentation explains the reduction.
`53`	Discontinued procedure	Use when procedure is started but discontinued due to extenuating circumstances; operative note must explain reason.
`59`	Distinct procedural service	Use to indicate a separate, distinct procedure was performed on the same day that is not normally reported together.
`62`	Two surgeons	Use when two surgeons work together as primary surgeons performing distinct portions of the complex shoulder reconstruction.
`78`	Return to operating room for related procedure by same physician	Use when a related procedure on the same shoulder is performed during the global period due to a complication.
`79`	Unrelated procedure or service by same physician during global period	Use when an unrelated procedure is performed during the global period.
`80`	Assistant surgeon	Use to indicate assistant surgeon services during the procedure when permitted.
`81`	Minimum assistant surgeon	Use when a minimal assistant surgeon provided limited assistance and payer accepts `81`.
`82`	Assistant surgeon when qualified resident unavailable	Use when an assistant is required because a qualified resident is unavailable.
`59`	Distinct procedural service (alternate)	Use when another procedure performed same day needs separation by site or service; some payors prefer modifier `59` over others.

Taxonomy Code	Specialty	Notes
207X00000X	Orthopaedic Surgery	Primary specialty performing complex shoulder reconstructions including open and arthroscopic procedures.
2080P0206X	Hand Surgery (Orthopedic)	Orthopedic hand/upper-extremity surgeons who manage complex shoulder/upper extremity reconstruction.
207L00000X	Sports Medicine (Orthopedic)	Specialists focusing on shoulder instability and rotator cuff pathology who may perform combined procedures.
2084P0800X	Shoulder and Elbow Surgery	Subspecialists concentrating on advanced reconstructive shoulder procedures.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`M75.121`	Complete rotator cuff tear or rupture of right shoulder, not specified as traumatic	Rotator cuff tears frequently necessitate complex repair or reconstruction procedures captured by an unlisted shoulder code when combined or atypical techniques are used.
`M75.122`	Complete rotator cuff tear or rupture of left shoulder, not specified as traumatic	See above for contralateral presentations requiring similar complex reconstruction.
`M24.211`	Recurrent dislocation, right shoulder	Chronic instability with recurrent dislocations may require capsular plication or reconstructive procedures included in an unlisted shoulder code.
`M24.212`	Recurrent dislocation, left shoulder	Same clinical relevance for the left shoulder.
`M75.51`	Biceps tendinitis, right shoulder	Biceps pathology is commonly addressed during shoulder reconstructions and can be part of the unlisted procedure.
`M75.52`	Biceps tendinitis, left shoulder	As above for left shoulder.
`M19.011`	Primary osteoarthritis, right shoulder	Advanced degenerative change may require debridement, contouring, or reconstructive techniques captured by `23929`.
`S43.431A`	Superior glenohumeral ligament sprain of right shoulder, initial encounter	Acute complex traumatic injuries with multi-structure damage may be treated with combined procedures billed with an unlisted shoulder code.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`23410`	Repair of ruptured musculotendinous cuff (eg, rotator cuff), open; acute	May represent a primary rotator cuff repair component when a specific repair code is available; used as a comparable code when parts of the open repair are performed.
`29827`	Arthroscopy, shoulder, surgical; with rotator cuff repair	Performed arthroscopically for rotator cuff repair components; may be performed before or instead of an open component—often referenced when mixed arthroscopic and open techniques are used.
`23465`	Tenodesis of long tendon of biceps, open; with tenodesis	Performed when concurrent biceps pathology is addressed during complex shoulder reconstruction.
`23130`	Excision, clavicle; distal end	Performed when distal clavicle resection is required as part of a more complex shoulder procedure to address acromioclavicular arthritis or impingement.
`29999`	Unlisted procedure, arthroscopy	Used for arthroscopic procedures without a specific code; may be submitted for arthroscopic components not otherwise described by established codes and can be billed alongside or compared to `23929`.

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.