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Official Description

Excision or curettage of bone cyst or benign tumor, tibia or fibula;

© Copyright 2025 American Medical Association. All rights reserved.

Common Language Description

The procedure described by CPT® Code 27635 involves the excision or curettage of a bone cyst or benign tumor located in the tibia or fibula. A bone cyst is defined as a fluid-filled space within the bone, which can vary in type. The unicameral or simple bone cyst is the most common form, characterized as a benign lesion. Another type, the aneurysmal bone cyst, is less common and consists of vascular tissue that surrounds a blood-filled cystic lesion. Additionally, there are various benign bone tumors, including giant cell tumors, chondromyxoid fibromas, and enchondromas. During the procedure, an incision is made over the lesion site on the tibia or fibula, allowing for dissection of the soft tissues to expose the lesion. If a cystic lesion is identified, the bone is incised to create a window, enabling access to the cyst. The fluid within the cyst is aspirated and sent for laboratory analysis. A curette is then utilized to remove the lining of the cystic cavity completely. In cases where benign tumors are present, the procedure may involve excising the tumor along with a margin of healthy bone. This comprehensive approach ensures that the lesion is adequately addressed while minimizing the risk of recurrence.

© Copyright 2025 Coding Ahead. All rights reserved.

1. Indications

The procedure described by CPT® Code 27635 is indicated for the treatment of specific conditions affecting the tibia or fibula, particularly when a bone cyst or benign tumor is present. The following conditions may warrant this procedure:

  • Bone Cyst: A fluid-filled space within the bone that may require intervention due to size, symptoms, or risk of fracture.
  • Benign Tumors: Non-cancerous growths such as giant cell tumors, chondromyxoid fibromas, and enchondromas that may cause pain, swelling, or functional impairment.

2. Procedure

The procedure for CPT® Code 27635 involves several critical steps to ensure the effective excision or curettage of the bone cyst or benign tumor:

  • Step 1: An incision is made in the skin directly over the site of the lesion located in the tibia or fibula. This initial step is crucial for gaining access to the underlying structures.
  • Step 2: The soft tissues surrounding the lesion are carefully dissected to expose the lesion fully. This dissection must be performed with precision to avoid damaging adjacent tissues.
  • Step 3: If a cystic lesion is identified, the bone is incised to create a window that allows access to the cyst. This step is essential for the subsequent aspiration of the cystic fluid.
  • Step 4: The fluid within the cyst is aspirated and sent to the laboratory for analysis. This analysis may provide important information regarding the nature of the cyst.
  • Step 5: A curette is inserted through the created bone window to remove the lining of the cystic cavity completely. This thorough curettage is necessary to minimize the risk of recurrence.
  • Step 6: In cases where a benign tumor is present, the lesion is excised along with a margin of surrounding healthy bone. This excision is performed to ensure complete removal of the tumor.

3. Post-Procedure

Post-procedure care following the excision or curettage of a bone cyst or benign tumor typically involves monitoring for any signs of complications, such as infection or excessive bleeding. Patients may be advised to limit weight-bearing activities on the affected limb to promote healing. Follow-up appointments are essential to assess the surgical site and ensure proper recovery. Additionally, any fluid sent for laboratory analysis will be reviewed to determine the nature of the cyst or tumor, which may influence further treatment or monitoring strategies.

Short Descr REMOVE LOWER LEG BONE LESION
Medium Descr EXCISION/CURETTAGE BONE CYST/TUMOR TIBIA/FIBULA
Long Descr Excision or curettage of bone cyst or benign tumor, tibia or fibula;
Status Code Active Code
Global Days 090 - Major Surgery
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 2 - Standard payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 1 - 150% payment adjustment for bilateral procedures applies.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 1 - Statutory payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 1 - Co-surgeons could be paid, though supporting documentation is required...
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Hospital Part B services paid through a comprehensive APC
ASC Payment Indicator Surgical procedure on ASC list in CY 2007; payment based on OPPS relative payment weight.
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P5B - Ambulatory procedures - musculoskeletal
MUE 1
CCS Clinical Classification 142 - Partial excision bone
22 Increased procedural services: when the work required to provide a service is substantially greater than typically required, it may be identified by adding modifier 22 to the usual procedure code. documentation must support the substantial additional work and the reason for the additional work (ie, increased intensity, time, technical difficulty of procedure, severity of patient's condition, physical and mental effort required). note: this modifier should not be appended to an e/m service.
50 Bilateral procedure: unless otherwise identified in the listings, bilateral procedures that are performed at the same session, should be identified by adding modifier 50 to the appropriate 5 digit code. note: this modifier should not be appended to designated "add-on" codes (see appendix d).
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
52 Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use).
58 Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
62 Two surgeons: when 2 surgeons work together as primary surgeons performing distinct part(s) of a procedure, each surgeon should report his/her distinct operative work by adding modifier 62 to the procedure code and any associated add-on code(s) for that procedure as long as both surgeons continue to work together as primary surgeons. each surgeon should report the co-surgery once using the same procedure code. if additional procedure(s) (including add-on procedure(s) are performed during the same surgical session, separate code(s) may also be reported with modifier 62 added. note: if a co-surgeon acts as an assistant in the performance of additional procedure(s), other than those reported with the modifier 62, during the same surgical session, those services may be reported using separate procedure code(s) with modifier 80 or modifier 82 added, as appropriate.
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
77 Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
78 Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period: it may be necessary to indicate that another procedure was performed during the postoperative period of the initial procedure (unplanned procedure following initial procedure). when this procedure is related to the first, and requires the use of an operating/procedure room, it may be reported by adding modifier 78 to the related procedure. (for repeat procedures, see modifier 76.)
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
80 Assistant surgeon: surgical assistant services may be identified by adding modifier 80 to the usual procedure number(s).
82 Assistant surgeon (when qualified resident surgeon not available): the unavailability of a qualified resident surgeon is a prerequisite for use of modifier 82 appended to the usual procedure code number(s).
99 Multiple modifiers: under certain circumstances 2 or more modifiers may be necessary to completely delineate a service. in such situations modifier 99 should be added to the basic procedure, and other applicable modifiers may be listed as part of the description of the service.
AG Primary physician
AS Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery
GC This service has been performed in part by a resident under the direction of a teaching physician
GW Service not related to the hospice patient's terminal condition
LT Left side (used to identify procedures performed on the left side of the body)
RT Right side (used to identify procedures performed on the right side of the body)
SG Ambulatory surgical center (asc) facility service
T2 Left foot, third digit
T9 Right foot, fifth digit
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
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2010-01-01 Changed Code description changed.
Pre-1990 Added Code added.
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