Nervous System Coding in ICD-10-CM/PCS

By Melanie Endicott, MBA/HCM, RHIA, CCS, CCS-P

ICD-10-CM/PCS will capture a greater level of specificity for nervous system coding. This article highlights some of the new features in coding central and peripheral nervous system cases with ICD-10-CM/PCS.

Nervous System ICD-10-CM Diagnosis Coding

Nervous system diagnosis codes are assigned from chapter 6 of ICD-10-CM, "Diseases of the Nervous System." This chapter includes categories G00–G99, which are arranged into the following blocks:

  • G00–G09, Inflammatory diseases of the central nervous system
  • G10–G14, Systemic atrophies primarily affecting the central nervous system
  • G20–G26, Extrapyramidal and movement disorders
  • G30–G32, Other degenerative diseases of the nervous system
  • G35–G37, Demyelinating diseases of the central nervous system
  • G40–G47, Episodic and paroxysmal disorders
  • G50–G59, Nerve, nerve root, and plexus disorders
  • G60–G65, Polyneuropathies and other disorders of the peripheral nervous system
  • G70–G73, Diseases of myoneural junction and muscle
  • G80–G83, Cerebral palsy and other paralytic syndromes
  • G89–G99, Other disorders of the nervous system

Sense organs have been separated from nervous system disorders, creating two new chapters for diseases of the eye and adnexa (chapter 7) and of the ear and mastoid process (chapter 8).

A few conditions have been moved from ICD-9-CM chapter 7, "Diseases of the Circulatory System," to ICD-10-CM chapter 6. These include basilar and carotid artery syndromes, transient global amnesia, and transient cerebral ischemic attack.

A note in categories G82 (Paraplegia and quadriplegia) and G83 (Other paralytic syndromes) states:

This category is to be used only when the listed conditions are reported without further specification, or are stated to be old or longstanding but of unspecified cause. The category is also for use in multiple coding to identify these conditions resulting from any cause.

Codes from category G81, Hemiplegia and hemiparesis, and subcategories, G83.1, Monoplegia of lower limb, G83.2, Monoplegia of upper limb, and G83.3, Monoplegia, unspecified, identify whether the dominant or nondominant side is affected. Should the affected side be documented but not specified as dominant or nondominant and the classification system does not indicate a default, code selection is as follows:

  • For ambidextrous patients, the default is dominant
  • If the left side is affected the default is nondominant
  • If the right side is affected the default is dominant

The terminology for epilepsy has been updated, with terms to classify the disorder such as localization-related idiopathic epilepsy, generalized idiopathic epilepsy, and special epileptic syndromes. Within those various categories, more specificity is possible, such as identifying seizures of localized onset, complex partial seizures, and intractable and status epilepticus.

A note in categories G40, Epilepsy and recurrent seizures, and G43, Migraine, notes that the terms pharmacoresistent (pharmacologically resistant), treatment resistant, refractory (medically), and poorly controlled are considered equivalent to intractable.

Seven Characters of a Medical and Surgical Code

Character 1


Character 2

Body System

Character 3

Root Operation

Character 4

Body Part

Character 5


Character 6


Character 7


Root Operations of the Central and Peripheral Nervous System

There are 20 root operations relevant to the central and peripheral nervous system. Coders should begin familiarizing themselves with the root operations and their definitions to prepare for coding in ICD-10-PCS.

Root Operation


Bypass (1)

Altering the route of passage of the contents of a tubular body part

Change (2)

Taking out or off a device from a body part and putting back an identical or similar device in or on the same body part without cutting or puncturing the skin or a mucous membrane

Destruction (5)

Physical eradication of all or a portion of a body part by the direct use of energy, force, or a destructive agent

Division (8)

Cutting into a body part, without draining fluids and/or gases from the body part, in order to separate or transect a body part

Drainage (9)

Taking or letting out fluids and/or gases from a body part

Excision (B)

Cutting out or off, without replacement, a portion of a body part

Extirpation (C)

Taking or cutting out solid matter from a body part

Extraction (D)

Pulling or stripping out or off all or a portion of a body part by the use of force

Fragmentation (F)

Breaking solid matter in a body part into pieces

Insertion (H)

Putting in a nonbiological appliance that monitors, assists, performs, or prevents a physiological function but does not physically take the place of a body part

Inspection (J)

Visually and/or manually exploring a body part

Map (K)

Locating the route of passage of electrical impulses and/or locating functional areas in a body part

Release (N)

Freeing a body part from an abnormal physical constraint

Removal (P)

Taking out or off a device from a body part

Repair (Q)

Restoring, to the extent possible, a body part to its normal anatomic structure and function

Reposition (S)

Moving to its normal location, or other suitable location, all or a portion of a body part

Resection (T)

Cutting out or off, without replacement, all of a body part

Supplement (U)

Putting in or on biological or synthetic material that physically reinforces and/or augments the function of a portion of a body part

Revision (W)

Correcting, to the extent possible, a portion of a malfunctioning device or the position of a displaced device

Transfer (X)

Moving, without taking out, all or a portion of a body part to another location to take over the function of all or a portion of a body part

Nervous System Procedure Coding in ICD-10-PCS

The central and peripheral nervous system are found in the medical and surgical section of ICD-10-PCS. All ICD-10-PCS codes are seven characters long with each of the seven characters representing an aspect of the procedure. The diagram at left illustrates the seven characters of a code from the medical and surgical section.

Medical and surgical codes have a first character of "0." The second character for the central nervous system is "0," while the second character for the peripheral nervous system is "1."

There are 20 root operations relevant to the central and peripheral nervous system, defined in the table on above. Coders should begin familiarizing themselves with the root operations and their definitions to prepare for ICD-10-PCS.

The body part values (fourth character) in the central and peripheral nervous system are numerous. The body part key in ICD-10-PCS is a table that lists each body part and its corresponding anatomical structures. Coders should become familiar with the body part key in learning to accurately assign ICD-10-PCS codes.

For instance, if a physician documents a neurolysis of the celiac plexus, which is not one of the listed body parts in the peripheral nervous system, coders can reference the body part key to identify the celiac plexus as a branch of the abdominal sympathetic nerve.

The fifth character specifies approach (i.e., open, via natural or artificial opening), and the sixth character indicates devices, such as a drainage device. The seventh and last character is a qualifier, which is specific to a particular root operation. The seventh character may be used to specify the destination of a bypass (e.g., atrium, urinary tract), a diagnostic procedure (e.g., biopsy), or the site receiving a nerve transfer (e.g., optic nerve, facial nerve).

Examples of procedures performed on the central and peripheral nervous system are revision of a VP shunt (00W600Z), percutaneous radiofrequency coagulation of the trigeminal nerve (005K3ZZ), suturing of the ulnar nerve (01Q40ZZ), left carpal tunnel release (01N50ZZ), and severing of the sciatic nerve via percutaneous endoscopic approach (018F4ZZ).


AHIMA. "CATS ICD-10-PCS A&P Focus: Central and Peripheral Nervous Systems Course." Available for purchase at

Centers for Medicare and Medicaid Services. "2011 ICD-10-PCS."

National Center for Health Statistics. "2011 ICD-10-CM Official Guidelines for Coding and Reporting."

National Center for Health Statistics. "2011 ICD-10-CM."

Melanie Endicott ( is a professional practice resource specialist at AHIMA.

Article citation:
Endicott, Melanie. "Nervous System Coding in ICD-10-CM/PCS" Journal of AHIMA 82, no.6 (June 2011): 62-64.