Nerve mapping is a method used to locate nerves and assess their function in real time during a surgical procedure. This technique helps surgeons identify nerves and monitor their health throughout the operation. By sending small electrical signals, the system detects nerve impulses and their corresponding muscle reactions. This provides the surgical team with immediate feedback to enhance procedural precision.
The Goal of Nerve Mapping
The primary objective of nerve mapping is to locate and identify nerves within the surgical field, helping surgeons avoid unintentional damage. This guidance is particularly helpful in complex surgeries where nerves may be difficult to distinguish from surrounding tissue. It acts as a specialized GPS for the nervous system, guiding instruments away from important neural pathways.
Another function is to monitor a nerve’s integrity throughout a procedure. The technology can detect signs of stress or potential injury, alerting the surgeon before damage becomes permanent. This continuous feedback allows for real-time adjustments to preserve the patient’s neurological function.
Finally, nerve mapping is used to confirm a nerve is functioning correctly after an intervention or before the surgical site is closed. By stimulating the nerve and observing the expected response, surgeons can be more confident the procedure was successful. This verification helps ensure functions like muscle movement are maintained post-surgery.
Common Nerve Mapping Techniques
A widely used method for nerve mapping is electromyography (EMG). A surgeon uses a handheld probe to deliver a low-level electrical pulse to tissues in the surgical area. If the probe stimulates a motor nerve, it triggers a muscle contraction detected by electrodes on the patient’s skin. This response is translated into a visual and audible signal, confirming the nerve’s location and function.
For surgeries involving the spinal cord and brain, surgeons use evoked potentials. These tests assess the entire nerve pathway from the peripheral limbs to the brain. Somatosensory Evoked Potentials (SSEPs) monitor sensory pathways by stimulating a nerve in an arm or leg and recording the signal as it travels to the brain.
Conversely, Motor Evoked Potentials (MEPs) assess the motor pathways that control muscle movement. The brain’s motor cortex is stimulated, and the resulting electrical signal is recorded from muscles in the limbs. This confirms the pathway from the brain to the muscles is intact. Together, SSEP and MEP provide a comprehensive picture of the spinal cord’s health during a procedure.
Surgical Procedures Utilizing Nerve Mapping
Nerve mapping is applied in head and neck surgeries where cranial nerves are at risk. During thyroid and parathyroid gland removal, surgeons protect the recurrent laryngeal nerve, which controls the voice box. In surgeries involving the parotid gland, the facial nerve, which governs all facial expressions, is mapped to prevent facial paralysis.
In neurosurgery, nerve mapping is used when removing brain tumors to identify and map areas of the brain that control motor function and speech. This allows surgeons to excise the tumor while preserving these functions. It is also used in surgeries to remove acoustic neuromas to protect the nearby facial nerve.
Spinal surgery is another area where nerve mapping is standard practice. In procedures like scoliosis correction or spinal fusion, there is a risk of damage to the spinal cord and nerve roots. Continuous monitoring with SSEP and MEP allows the surgical team to detect potential compression or injury, helping to prevent outcomes like paralysis or loss of sensation.