| G89 | Pain, not elsewhere classified |
| G89.0 | Central pain syndrome |
| G89.1 | Acute pain, not elsewhere classified |
| G89.11 | Acute pain due to trauma |
| G89.12 | Acute post-thoracotomy pain |
| G89.18 | Other acute postprocedural pain |
| G89.2 | Chronic pain, not elsewhere classified |
| G89.21 | Chronic pain due to trauma |
| G89.22 | Chronic post-thoracotomy pain |
| G89.28 | Other chronic postprocedural pain |
| G89.29 | Other chronic pain |
| G89.3 | Neoplasm related pain (acute) (chronic) |
| G89.4 | Chronic pain syndrome |
| G90 | Disorders of autonomic nervous system |
| G90.0 | Idiopathic peripheral autonomic neuropathy |
| G90.01 | Carotid sinus syncope |
| G90.09 | Other idiopathic peripheral autonomic neuropathy |
| G90.1 | Familial dysautonomia [Riley-Day] |
| G90.2 | Horner's syndrome |
| G90.3 | Multi-system degeneration of the autonomic nervous system |
| G90.4 | Autonomic dysreflexia |
| G90.5 | Complex regional pain syndrome I (CRPS I) |
| G90.50 | Complex regional pain syndrome I, unspecified |
| G90.51 | Complex regional pain syndrome I of upper limb |
| G90.511 | Complex regional pain syndrome I of right upper limb |
| G90.512 | Complex regional pain syndrome I of left upper limb |
| G90.513 | Complex regional pain syndrome I of upper limb, bilateral |
| G90.519 | Complex regional pain syndrome I of unspecified upper limb |
| G90.52 | Complex regional pain syndrome I of lower limb |
| G90.521 | Complex regional pain syndrome I of right lower limb |
| G90.522 | Complex regional pain syndrome I of left lower limb |
| G90.523 | Complex regional pain syndrome I of lower limb, bilateral |
| G90.529 | Complex regional pain syndrome I of unspecified lower limb |
| G90.59 | Complex regional pain syndrome I of other specified site |
| G90.8 | Other disorders of autonomic nervous system |
| G90.9 | Disorder of the autonomic nervous system, unspecified |
| G91 | Hydrocephalus |
| G91.0 | Communicating hydrocephalus |
| G91.1 | Obstructive hydrocephalus |
| G91.2 | (Idiopathic) normal pressure hydrocephalus |
| G91.3 | Post-traumatic hydrocephalus, unspecified |
| G91.4 | Hydrocephalus in diseases classified elsewhere |
| G91.8 | Other hydrocephalus |
| G91.9 | Hydrocephalus, unspecified |
| G92 | Toxic encephalopathy |
| G93 | Other disorders of brain |
| G93.0 | Cerebral cysts |
| G93.1 | Anoxic brain damage, not elsewhere classified |
| G93.2 | Benign intracranial hypertension |
| G93.3 | Postviral fatigue syndrome |
| G93.4 | Other and unspecified encephalopathy |
| G93.40 | Encephalopathy, unspecified |
| G93.41 | Metabolic encephalopathy |
| G93.49 | Other encephalopathy |
| G93.5 | Compression of brain |
| G93.6 | Cerebral edema |
| G93.7 | Reye's syndrome |
| G93.8 | Other specified disorders of brain |
| G93.81 | Temporal sclerosis |
| G93.82 | Brain death |
| G93.89 | Other specified disorders of brain |
| G93.9 | Disorder of brain, unspecified |
| G94 | Other disorders of brain in diseases classified elsewhere |
| G95 | Other and unspecified diseases of spinal cord |
| G95.0 | Syringomyelia and syringobulbia |
| G95.1 | Vascular myelopathies |
| G95.11 | Acute infarction of spinal cord (embolic) (nonembolic) |
| G95.19 | Other vascular myelopathies |
| G95.2 | Other and unspecified cord compression |
| G95.20 | Unspecified cord compression |
| G95.29 | Other cord compression |
| G95.8 | Other specified diseases of spinal cord |
| G95.81 | Conus medullaris syndrome |
| G95.89 | Other specified diseases of spinal cord |
| G95.9 | Disease of spinal cord, unspecified |
| G96 | Other disorders of central nervous system |
| G96.0 | Cerebrospinal fluid leak |
| G96.1 | Disorders of meninges, not elsewhere classified |
| G96.11 | Dural tear |
| G96.12 | Meningeal adhesions (cerebral) (spinal) |
| G96.19 | Other disorders of meninges, not elsewhere classified |
| G96.8 | Other specified disorders of central nervous system |
| G96.9 | Disorder of central nervous system, unspecified |
| G97 | Intraoperative and postprocedural complications and disorders of nervous system, not elsewhere classified |
| G97.0 | Cerebrospinal fluid leak from spinal puncture |
| G97.1 | Other reaction to spinal and lumbar puncture |
| G97.2 | Intracranial hypotension following ventricular shunting |
| G97.3 | Intraoperative hemorrhage and hematoma of a nervous system organ or structure complicating a procedure |
| G97.31 | Intraoperative hemorrhage and hematoma of a nervous system organ or structure complicating a nervous system procedure |
| G97.32 | Intraoperative hemorrhage and hematoma of a nervous system organ or structure complicating other procedure |
| G97.4 | Accidental puncture and laceration of a nervous system organ or structure during a procedure |
| G97.41 | Accidental puncture or laceration of dura during a procedure |
| G97.48 | Accidental puncture and laceration of other nervous system organ or structure during a nervous system procedure |
| G97.49 | Accidental puncture and laceration of other nervous system organ or structure during other procedure |
| G97.5 | Postprocedural hemorrhage and hematoma of a nervous system organ or structure following a procedure |
| G97.51 | Postprocedural hemorrhage and hematoma of a nervous system organ or structure following a nervous system procedure |
| G97.52 | Postprocedural hemorrhage and hematoma of a nervous system organ or structure following other procedure |
| G97.8 | Other intraoperative and postprocedural complications and disorders of nervous system |
| G97.81 | Other intraoperative complications of nervous system |
| G97.82 | Other postprocedural complications and disorders of nervous system |
| G98 | Other disorders of nervous system not elsewhere classified |
| G98.0 | Neurogenic arthritis, not elsewhere classified |
| G98.8 | Other disorders of nervous system |
| G99 | Other disorders of nervous system in diseases classified elsewhere |
| G99.0 | Autonomic neuropathy in diseases classified elsewhere |
| G99.2 | Myelopathy in diseases classified elsewhere |
| G99.8 | Other specified disorders of nervous system in diseases classified elsewhere |