Periphral Nerve Injury

Peripheral nerve injury & Brachial plexus •Mechanisms of injury: Laceration Cut of nerve by a sharp thing (glass, knife, metal) causing sharp devision of the nerve (2 ends), can also be partial laceration. Sharp laceration clean cat (as knife) → Broome iconect the 2 endi Blunt laceration Multiple cuts by many sharp surfaces, leading to tiểu of the nerve (as by chainsaw, fan blades, fracture butter knife) → Not repaired wmediatly want & month for the to subonde, then cut frie 2 edges fuse goatt to Coanent mena (Sural nerve grafit). Nοίοπεπταίσιο Exam question: Patient had a knife fight and is presenting with median. nerve Palsy (knife was in arm/forearm), what's your management? * al close the skin and send him home * Tell him to come back in 3 months after spontanous recovery * Take him to OR, give tetanus prophylaxis & ABFs, explore the wound Exam question: Patient came with Compound Fracture of the humorus and ortho did external fixation * wart until external Fixator is removed (7 month) then repair Stretch injuries / Traction most of plexus injuries and nerve injuries associated with Fractures, hip dislocations (sciatic nerve), closed Fracture of femur (anterior interosseous nerve), Tibial fracture (Common peroneal nerve) Nerve not cut, still intact and sheeth covering it. Can be spontanously healed. we only need Y3 of axons to reach the distal target in order to have normal function. Exam question: Patient came with broken humerus (spiral fracture) and wrist drop, fixed by ortho using intramedullary nails. How to manage the median nerve palsy? →Follow up patient after 3 months (most likely a stretch injury) no need to explore nerve. Same with femur fracture with sciatic n. injury. Compression. Caused by nerve entrapment (tunnel syndromes) Pressure caused by excessive pressure over nerve on an unconscious patient (anesthesia injury, saturday night palsy of alcohol, tight cast or tourniquet) 5) Electrical rare. caused by high voltage electricity passing through the nerve. Ischemia usually with fractures cutting off blood supply can be prevented by prophylactic fasciatamy. Avulsion Type of injury specific to plexuses (usually brachial plexus), where the nerve root is pulled out of the spinal cord. No chance of spontaneous recovery operate. In case of plexus injury we must check patient is stable know whether it's traction or avulsion, because traction is treated conservatively. Indications of brachial plexus avulsion [1] Involvement of long thoracic n. Supplies Serratus anterior muscle winged scapula [2] Involvement of Phrenic nerve Supplies the diaphragm elevation of hemidiaphragm on chest x-ray [3] Horner Syndrome Prosis & myosis of eye due to cut of sympathetic. Supply (avulsion of T1) Specific peripheral nerve injuries: [1] median nerve → slash wrist or spaghetti wrist EMERGENCY cutting of wrist injures: radial a., ulnar a, median n., ulnar n. and all tendons. Repair immediately by this order: ① arteries ② tendons ③ nerves [2] ulnar nerve → Evidence of external trauma to forearm with Partial claw hand → operative repair, not emergency. ulnar nerve is difficult to heal. [3] Radial nerve wrist drop (loss of extension). Example is humerous compound fracture → Blunt lacerations, wait 1 month then operate Obstetric brachial plexus injury Shoulder dystocia Risk factors: big baby (>4 kg), Cephalopelvic disproportion, Primigravida. Picture: adducted arm & internal rotation, but the wrist grip is ok → Erb's palsy (injury to upper trunk) (C5,6 Musculocutanous n. Suprascapular n. • Usually stretch injury, can be avulsion • 75% recover spontaneously in first 2 months. • In those who do not recover, the earlier the surgery the better. injuries that are >1 year old are inoperable due to neuromuscular junction atrophy. operation done after no improvement in 4 months. • Presence of Horner syndrome with completely flaccid arm → Total brachial plexus injury • outcome of brachial plexus injury in children is better than adults. Injection injuries: Intramuscular injections given in upper outer quadrant of bottock. • injury to sciatic nerve is caused by the injected fluid not the needle in most cases. Always ask the patient to report any numbness and inject slowly. Gunshot injury • doesn't transect the nerve. It remains in Continuity, so no need to operate unless there's vascular injury (example expanding hematoma)