craniotomy

DEFINITION of craniotomy

Craniotomy is a neurosurgical procedure in which a surgeon removes a section of bone (bone flap) from the skull to expose the underlying dura mater and brain, performs the intended intracranial procedure, and then replants and fixates the bone flap at closure. It is distinguished from craniectomy, in which the bone flap is not replaced (often left off temporarily or permanently to allow for brain swelling, as in decompressive procedures). The mechanism is purely mechanical/structural — it does not itself treat disease, but rather provides surgical access for evacuation of hematoma, tumor resection, aneurysm clipping, abscess drainage, or decompression. Craniotomy can be planned (elective, e.g., tumor resection) or emergent (e.g., evacuation of an expanding traumatic hematoma). Common approaches coded in CPT include exploratory (61304-61305), hematoma evacuation (61312-61315), abscess drainage (61320-61321), and decompressive craniectomy (61322-61323). craniotomy is often confused with burr hole procedures — burr holes are small drill openings without removal of a bone flap, used for taps, punctures, ICP monitor placement, or limited hematoma drainage, and are coded separately (61105-61253) — and with cranioplasty, which is the reconstructive repair of a skull defect (62140-62147), not the original access procedure.

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ETYMOLOGY of craniotomy

greek

Component	Origin	Meaning
o-	Greek κρανίον (kraníon) (“skull”)	“skull,” “cranium” — combining form denoting the bony structure enclosing the brain
-tomy	Greek τομή (tomḗ), from témnein (“to cut”)	“incision into,” “cutting operation” — denotes a surgical cut without removal of tissue
-ectomy	Greek ektomē, from ek- (“out”) + tomē (“a cutting”)	Noun-forming suffix — “surgical removal of”

The word entered English medical usage in the 1870s as craniotomy (noun), formed directly in English/New Latin from Greek kranion (“skull”) + tomia (“cutting”), on the model of other surgical -tomy terms. Historically the term also referred to a destructive obstetric procedure performed on a fetal skull during difficult delivery — a usage now archaic and distinct from the modern neurosurgical meaning. The root tomē (“a cutting”) connects craniotomy to the entire -tomy family: laparotomy (incision into the abdomen), tracheotomy (incision into the trachea), and osteotomy (surgical cutting of bone). The combining form cranio- is highly productive in neurosurgical and skeletal terminology, appearing in craniectomy, cranioplasty, craniosynostosis, and craniofacial.

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🔀 ALIASES / ALTERNATE TERMS

• Craniotomic (adjective form — “craniotomic approach,” “craniotomic flap”)
• Bone flap craniotomy (clinical descriptor emphasizing that the bone segment is replaced, distinguishing it from craniectomy)
• Osteoplastic craniotomy (older/formal surgical term for the same bone-flap-replaced technique)
• Decompressive craniectomy (distinct related procedure — bone flap intentionally NOT replaced; CPT 61322-61323)
• Exploratory craniotomy (craniotomy performed for diagnostic exposure rather than a predetermined therapeutic target; CPT 61304-61305)
• Craniotomy for evacuation of hematoma (therapeutic subtype for traumatic or spontaneous intracranial hemorrhage; CPT 61312-61315)
• Craniotomy for tumor resection (subtype for excision of intracranial neoplasm)
• Pterional craniotomy (anatomic-approach subtype — frontotemporal approach commonly used for aneurysm clipping)
• Suboccipital craniotomy/craniectomy (posterior fossa approach subtype; often coded as infratentorial, e.g., 61305, 61314-61315)

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🔗 RELATED TERMS

• Craniectomy — the related procedure in which the bone flap is removed and not replaced (temporarily or permanently); performed for decompressive purposes when brain swelling is anticipated.
• Cranioplasty — shares the o- root; the reconstructive repair or replacement of a skull defect, often performed weeks to months after a decompressive craniectomy (CPT 62140-62147).
• burr hole — a smaller diagnostic or therapeutic drill-hole access procedure not involving a bone flap; used for ICP monitor placement, ventriculostomy, or limited hematoma drainage (CPT 61105-61253).
• Subdural hematoma — a common indication for emergent craniotomy; collection of blood between the dura and arachnoid mater, often traumatic in origin.
• Epidural hematoma — another common traumatic indication for craniotomy; blood collects between the dura mater and skull, classically associated with middle meningeal artery injury.
• Decompressive craniectomy — surgical technique used to relieve elevated intracranial pressure (ICP) that cannot be controlled medically; distinguished from craniotomy by non-replacement of the bone flap.
• Intracranial pressure — the physiological parameter craniotomy/craniectomy is frequently performed to relieve, particularly in decompressive procedures.
• meningioma — a common benign intracranial tumor (D32.0-D32.9) frequently requiring craniotomy for resection.
• glioblastoma — an aggressive malignant primary brain tumor (C71.9) commonly requiring craniotomy for maximal safe resection.
• Aneurysm clipping — a therapeutic procedure performed via craniotomy to occlude a cerebral aneurysm and prevent rupture or rebleeding.
• CT/MRI brain imaging — primary diagnostic tools used to identify the hematoma, tumor, or lesion that establishes medical necessity for craniotomy.

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CODING CORNER

🏥 ICD-10-CM CODES (Indications & Postprocedural Status — Craniotomy Is a Procedure, Not a Diagnosis)

Traumatic Intracranial Hemorrhage (Common Emergent Indications — Laterality/7th Character Required)

Code	Description
S06.5X0A	Traumatic subdural hemorrhage without loss of consciousness, initial encounter
S06.5X9A	Traumatic subdural hemorrhage with loss of consciousness of unspecified duration, initial encounter
S06.4X0A	Epidural hemorrhage without loss of consciousness, initial encounter
S06.4X9A	Epidural hemorrhage with loss of consciousness of unspecified duration, initial encounter
S06.362A	Traumatic hemorrhage of left cerebrum, initial encounter
S06.361A	Traumatic hemorrhage of right cerebrum, initial encounter

Spontaneous Intracranial Hemorrhage (Non-Traumatic Indications)

Code	Description
I61.0	Nontraumatic intracerebral hemorrhage in hemisphere, subcortical
I61.1	Nontraumatic intracerebral hemorrhage in hemisphere, cortical
I61.6	Nontraumatic intracerebral hemorrhage, multiple localized
I60.9	Nontraumatic subarachnoid hemorrhage, unspecified
I62.00	Nontraumatic subdural hemorrhage, unspecified

Intracranial Neoplasm (Elective/Oncologic Indications)

Code	Description
C71.9	Malignant neoplasm of brain, unspecified
C71.1	Malignant neoplasm of frontal lobe
D32.0	Benign neoplasm of cerebral meninges
D33.2	Benign neoplasm of brain, unspecified
D43.2	Neoplasm of uncertain behavior of brain, unspecified

Postprocedural Status / Aftercare (Assign When Applicable to This Encounter)

Code	Description
Z98.890	Other specified postprocedural states — history of craniotomy, no active management
Z48.811	Encounter for surgical aftercare following surgery on the nervous system
G97.82	Other postprocedural complications and disorders of nervous system
G97.31	Intraoperative hemorrhage and hematoma of a nervous system organ or structure complicating a nervous system procedure
G97.51	Postprocedural hemorrhage of a nervous system organ or structure following a nervous system procedure

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🔧 COMMON CPT CODES (Craniotomy/Craniectomy — Surgical Procedures on the Skull, Meninges, and Brain)

CPT Code	Description
61304	Craniectomy or craniotomy, exploratory; supratentorial
61305	Craniectomy or craniotomy, exploratory; infratentorial (posterior fossa)
61312	Craniectomy or craniotomy for evacuation of hematoma, supratentorial; extradural or subdural
61313	Craniectomy or craniotomy for evacuation of hematoma, supratentorial; intracerebral
61314	Craniectomy or craniotomy for evacuation of hematoma, infratentorial; extradural or subdural
61315	Craniectomy or craniotomy for evacuation of hematoma, infratentorial; intracerebellar
61320	Craniectomy or craniotomy, drainage of intracranial abscess; supratentorial
61321	Craniectomy or craniotomy, drainage of intracranial abscess; infratentorial
61322	Craniectomy or craniotomy, decompressive, with or without duraplasty, for treatment of intracranial hypertension, without evacuation of associated intraparenchymal hematoma
61323	Craniectomy or craniotomy, decompressive, with or without duraplasty, for treatment of intracranial hypertension, with evacuation of associated intraparenchymal hematoma
61510	Craniectomy, trephination, bone flap craniotomy; for excision of brain tumor, supratentorial, except meningioma

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⚠️ Coding Note: craniotomy/craniectomy CPT codes (61304-61576 range) are site-specific (supratentorial vs. infratentorial) and often laterality-dependent in the operative note, so pull the specific approach and anatomic location directly from the op note rather than defaulting to an exploratory code. Sequencing: code the underlying diagnosis prompting the craniotomy (traumatic hematoma, tumor, abscess) as principal/first-listed when it meets the definition of principal diagnosis; the postprocedural Z-codes (Z98.890, Z48.811) are for subsequent encounters after the acute episode, not the surgical encounter itself. A frequently undercoded scenario on inpatient profee claims is decompressive craniectomy performed with hematoma evacuation — this must be coded 61323, not 61322 plus a separate hematoma evacuation code, since the “with evacuation” language is built into the CPT descriptor itself; watch operative notes for documentation like “decompressive craniectomy with evacuation of intraparenchymal hematoma” as the trigger phrase. Medicare and most commercial payers (BCBS, UHC, Cigna, Aetna) require medical necessity documentation tying the craniotomy to imaging findings (CT/MRI) in the record; missing imaging correlation is a common denial reason. If a craniotomy converts to craniectomy intraoperatively (bone flap not replaced due to swelling), code to the craniectomy/decompressive family, not the standard craniotomy code, even if originally planned as a craniotomy.

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DERIVATIONS of craniotomy

TABLE definition AS Definition
FROM #medterm 
WHERE length(filter(roots, (word) => econtains([[craniotomy]].roots, word))) > 0 AND file.name != [[craniotomy]].file.name
SORT file.name ASC

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Query functionality

TABLE definition AS Definition
FROM #medterm 
WHERE length(filter(definition, (word) => econtains([[craniotomy]].definition, word))) > 0 AND file.name != [[craniotomy]].file.name

Med terms dictionary Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms