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Official Description

Resection or excision of neoplastic, vascular or infectious lesion of base of anterior cranial fossa; intradural, including dural repair, with or without graft

© Copyright 2025 American Medical Association. All rights reserved.

Common Language Description

The CPT® Code 61601 refers to the surgical procedure involving the resection or excision of neoplastic, vascular, or infectious lesions located at the base of the anterior cranial fossa. This procedure is performed intradurally, which means it involves accessing the area beneath the dura mater, the protective membrane covering the brain. The operation includes dural repair, which is essential for maintaining the integrity of the central nervous system and preventing complications such as cerebrospinal fluid leaks. The procedure may be conducted with or without the use of graft materials, depending on the specific requirements of the case. The anterior cranial fossa is accessed through a separately reported approach, allowing for a thorough examination and treatment of lesions that may affect critical structures such as the olfactory bulb, cranial nerves, and blood vessels. The careful execution of this procedure is vital to ensure the preservation of these structures while effectively removing the lesion and repairing any dural defects that may arise during the operation.

© Copyright 2025 Coding Ahead. All rights reserved.

1. Indications

The procedure described by CPT® Code 61601 is indicated for the treatment of various conditions affecting the anterior cranial fossa. These include:

  • Neoplastic Lesions Tumors or abnormal growths that may be benign or malignant, requiring surgical intervention to remove.
  • Vascular Lesions Abnormal blood vessel formations, such as arteriovenous malformations, that may pose risks to surrounding structures or lead to complications.
  • Infectious Lesions Infections that have localized in the anterior cranial fossa, necessitating excision to prevent further complications or spread of infection.

2. Procedure

The procedure involves several critical steps to ensure effective resection or excision of the lesion:

  • Accessing the Anterior Fossa The anterior fossa is accessed using a separately reported approach, which allows the surgeon to reach the targeted area safely and effectively.
  • Extradural Resection The resection or excision is performed in a lateral to medial direction. The cribriform plate, a bony structure at the base of the skull, is examined for any lesion involvement.
  • Osteotomies and Cribriform Plate Removal If the cribriform plate is found to be involved with the lesion, osteotomies are performed to remove it en bloc along with the surrounding neoplastic, vascular, or infectious tissue, while taking care to preserve critical structures such as the olfactory bulb, cranial nerves, and blood vessels.
  • Exploration of the Sinus The sinus may be explored, and additional procedures such as rhinotomy, ethmoidectomy, maxillectomy, or maxillotomy may be performed as necessary to facilitate complete lesion removal.
  • Dural Management If the dura mater can be preserved, it is retracted back to the planum sphenoidale. A drill or chisel is then used to cut bone as needed to complete the resection or excision of the lesion.
  • Intradural Lesion Management If the lesion extends into the intradural space, the dural sleeves along the olfactory nerves are divided, and the dura is opened to allow for the resection or excision of the remaining lesion.
  • Dural Repair After the lesion is excised, the dural defect is repaired using sutures or graft materials, such as autologous pericranium or synthetic materials like acellular human dermis or collagen matrix, to ensure a watertight seal and prevent cerebrospinal fluid leakage.
  • Extradural Defect Filling The extradural defect may be filled with autologous graft material, such as fascia or fat, to promote healing and structural integrity.
  • Closure of the Skull Deficit The skull deficit is closed using the patient’s excised bone, cadaver bone graft, or a metal plate, followed by suturing the incision in layers to ensure proper healing.
  • Skin Closure The skin is typically closed using staples to secure the incision and promote recovery.

3. Post-Procedure

Post-procedure care involves monitoring for any complications, particularly cerebrospinal fluid leaks, which can occur if the dural repair is not watertight. Patients may require imaging studies to assess the integrity of the surgical site and ensure that there are no residual lesions. Recovery may involve pain management and observation for signs of infection or other complications. Follow-up appointments are essential to evaluate the healing process and the effectiveness of the procedure.

Short Descr RESECT/EXCISE CRANIAL LESION
Medium Descr RESCJ/EXC LES BASE ANT CRNL FOSSA INDRL W/WO GRF
Long Descr Resection or excision of neoplastic, vascular or infectious lesion of base of anterior cranial fossa; intradural, including dural repair, with or without graft
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) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 2 - Payment restriction for assistants at surgery does not apply to this procedure...
Co-Surgeons (62) 1 - Co-surgeons could be paid, though supporting documentation is required...
Team Surgery (66) 2 - Team surgeons permitted; pay by report.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Inpatient Procedures, not paid under OPPS
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P1G - Major procedure - Other
MUE 1
CCS Clinical Classification 1 - Incision and excision of CNS

This is a primary code that can be used with these additional add-on codes.

69990 Addon Code MPFS Status: Restricted APC N ASC N1 PUB 100 CPT Assistant Article 1Microsurgical techniques, requiring use of operating microscope (List separately in addition to code for primary procedure)
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).
GC This service has been performed in part by a resident under the direction of a teaching physician
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.
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).
53 Discontinued procedure: under certain circumstances, the physician or other qualified health care professional may elect to terminate a surgical or diagnostic procedure. due to extenuating circumstances or those that threaten the well being of the patient, it may be necessary to indicate that a surgical or diagnostic procedure was started but discontinued. this circumstance may be reported by adding modifier 53 to the code reported by the individual for the discontinued procedure. note: this modifier is not used to report the elective cancellation of a procedure prior to the patient's anesthesia induction and/or surgical preparation in the operating suite. for outpatient hospital/ambulatory surgery center (asc) 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.
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).
AS Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery
CR Catastrophe/disaster related
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)
Date
Action
Notes
1994-01-01 Added First appearance in code book in 1994.
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