CPT Code 43659: Unlisted Laparoscopic Procedure, Stomach

Use CPT 43659 for unlisted laparoscopic stomach procedures when no specific code fits. Includes billing tips, documentation advice, and Medicare guidance.

Use Code

What is CPT code 43659?

CPT code 43659 describes an unlisted laparoscopic procedure involving the stomach. It’s a placeholder code used when there is no specific CPT code that matches the procedure performed. Because it is unlisted, it must be supported with detailed documentation, including a description of the technique used and a comparison to an existing, related procedure.

You’ll often see 43659 used in bariatric surgery scenarios, such as when a surgeon performs a laparoscopic revision of a previous gastric operation or removes a gastric band with additional work that doesn’t quite match CPT 43772. Other cases might involve management of complications, custom pouch reconstructions, or hybrid techniques that don’t have a defined CPT equivalent.

What does an unlisted laparoscopic stomach procedure involve?

Laparoscopic stomach surgeries vary widely depending on the patient’s anatomy, surgical history, and the treatment goal. When the surgeon works on the stomach in a way that doesn’t conform to any standard procedural code, due to revisions, anatomical challenges, or a novel approach, may be used to represent the service.

Typical examples include:

Laparoscopic removal of a gastric band with unexpected adhesions or conversions
Non-standard revisional procedures following a gastric bypass
Laparoscopic management of leaks, fistulas, or failed anastomoses when no clear CPT code applies

Each of these scenarios represents a deviation from a known procedure and must be coded accordingly.

Documentation requirements for CPT 43659

Since this is an unlisted code, your claim depends on how well you justify the need for it. Payers, including those under the Medicare Physician Fee Schedule, will not reimburse CPT 43659 without a strong case. Here’s what your documentation should cover:

Operative report

Include a detailed, step-by-step account of the procedure performed: what structures were involved, what techniques were used, and what challenges were encountered. Clarify how this deviates from any standard stomach procedure.

Rationale for unlisted code use

Point out which specific code is closest in complexity or purpose (e.g., 43775 for sleeve gastrectomy), and explain why that code doesn’t capture what was done.

Medical necessity

Describe the clinical context—why the patient required surgery, what complications or prior procedures were involved, and why a custom or modified approach was necessary.

Suggested valuation

Payers will often ask for a recommended reimbursement. You can propose a fee based on the Medicare Physician Fee Schedule for the comparison code, especially if RVUs align closely.

Billing guidelines

CPT 43659 should only be used when no other code adequately describes the service. Don’t use it simply because the standard procedure was altered slightly. Instead, be clear that what was done falls outside existing code definitions.

Because there’s no assigned RVU, reimbursement will be reviewed manually by the payer. Always include:

The operative report
Comparison code with rationale
Suggested fee (if permitted)
Letter of medical necessity (especially for Medicare claims)

Also, keep in mind that some payers, particularly Medicare Advantage plans, may require prior authorization.

Applicable modifiers

Modifier 22 – Use if the surgery was significantly more complex than comparable procedures
Modifier 52 – For reduced services, if the procedure was incomplete
Modifier 59 – When the procedure is distinct from others done in the same session

Other related CPT codes

43775 – Laparoscopic sleeve gastrectomy
43770 – Laparoscopic placement of an adjustable gastric band
43772 – Laparoscopic removal of an adjustable gastric band
43771 – Laparoscopic procedure for revising or adjusting a gastric device

Frequently asked questions

Only when the procedure doesn’t match any available CPT code, even with the use of a modifier. This might apply when performing a one-off revision, a hybrid approach, or managing complex complications from prior bariatric surgery.

No. It can also be used for non-bariatric stomach procedures as long as they are laparoscopic and unlisted. Examples include managing perforations, gastric outlet obstructions, or anatomical corrections from congenital conditions.

Yes, but claims are manually reviewed. Make sure your documentation meets the medical necessity standard and aligns with guidance from your local Medicare Administrative Contractor.