Intracranial Pressure Monitoring Techniques [Neurosurgery Wiki]

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====== Intracranial Pressure Monitoring Techniques ======

===== 🧠 Invasive Techniques (Gold Standard) =====

==== Intraventricular Catheter (EVD – External Ventricular Drain) ====
  * **Location**: [[Lateral ventricle]]
  * **Advantages**:
    * [[Gold standard]] – measures true ICP
    * Allows [[cerebrospinal fluid]] (CSF) [[drainage]]
    * Can be recalibrated and zeroed
  * **Disadvantages**:
    * Requires anatomical precision
    * Risk of infection and hemorrhage

==== Intraparenchymal Monitor (e.g., Codman, Camino) ====
  * **Location**: Frontal white matter (brain parenchyma)
  * **Advantages**:
    * Easier and faster to place than [[EVD]]
    * Lower infection rate
  * **Disadvantages**:
    * Cannot drain CSF
    * Cannot be recalibrated – may drift over time

==== Subdural / Epidural Sensors ====
  * **Location**: Subdural or [[epidural space]]
  * **Advantages**:
    * Less invasive
  * **Disadvantages**:
    * Less accurate
    * Rarely used today

==== Subarachnoid Bolt ====
  * **Location**: [[Subarachnoid space]]
  * **Advantages**:
    * Moderate accuracy
  * **Disadvantages**:
    * Cannot drain CSF

===== 🩺 Non-Invasive Techniques (Adjuncts or Experimental) =====

==== Transcranial Doppler Ultrasonography (TCD) ====
  * Measures [[cerebral blood flow velocity]] and pulsatility index
  * Indirect correlation with ICP

==== Optic Nerve Sheath Diameter (ONSD) via Ultrasound ====
  * Detects [[optic nerve sheath]] dilation due to raised ICP
  * Rapid bedside screening tool

==== MRI / CT-Based Morphometrics ====
  * Measures ventricular size and brain shifts
  * Not continuous monitoring

==== Tympanic Membrane Displacement ====
  * Measures displacement due to CSF pressure transmission to cochlea
  * Experimental

===== 📊 Comparative Table =====

^ Parameter               ^ Intraventricular ^ Intraparenchymal ^ Non-Invasive       ^
| Accuracy                | High              | High              | Low–Medium         |
| CSF drainage            | Yes               | No                | No                 |
| Infection risk          | High              | Moderate          | None               |
| Recalibration possible  | Yes               | No                | No                 |
| ICU use                 | Yes               | Yes               | Rare/Adjunct only  |