Intraneural Injection in local anesthetic blocks and nerve damage.

Rationale:

Unintentional injection of local anesthetics directly into a nerve (intraneurally) has long been recognized as a possible cause of nerve injury. However, recent studies have shown that ultrasound-guided brachial plexus penetration and intraneural injection does not inevitably cause neurological damage. Reliable data on the relative frequency of inadvertent intraneural injection during peripheral nerve blocks and to what extent these may lead to neural injury are lacking.




Study Objective:

To determine the incidence of intraneural injection in electrical stimulation-guided nerve block with ultrasound visualisation, and to what extent intraneural injection leads to neurological sequelae at short-term and long-term follow-up.




Study design:

This is a large, multi-centre cohort study in 805 adult patients undergoing upper or lower extremity local block. Patients and anesthesiologists are blinded for the ultrasound data. In addition, experts who analyse the ultrasound-acquired data are also blinded for patient’s neurological status.

Eligibility:

Patients are eligible if they are undergoing upper or lower extremity block and are 16 years or older.




Study:

During peripheral nerve block, ultrasound data will be recorded just before, during and after injection. There will be no interference with the local standards of the procedure. The ultrasound data will than be analysed by two blinded, independent experts. All potential etiologic factors which are known to increase the risk of neurological damage are recorded (i.e., co-morbidities).




Follow-up:

The neurological status (motor and sensory) will be re-examined and recorded at their appearance for post-operative follow-up (3 days and 3 weeks), and after 3 months.




Primary outcome:

The occurrence of intraneural injections in electrical nerve stimulation-guided upper and lower extremity local anesthetic blocks as determined by ultrasound. Secondary outcome: the occurrence of patients with motor and/or sensory deficit at 3 days, 3 weeks and 3 months after the procedure. The results of both outcomes will be correlated for a possible relationship between intraneural injection and nerve damage.

Intraneural injection of anesthetics in upper and lower extremity blocks increases the risk of neurological damage.

3 days post-op, 3 weeks and 3 months.

Monitoring and recording the injection procedure.