Tasty Morsels of Critical Care 050 | Spinal cord injuries
Welcome back to the tasty morsels of critical care podcast. This is number 50, so for all 7 of you out there, well done for making it this far especially when you can’t even get CPD points for it. Today we’ll look at Oh’s Manual Chapter 80 written by the one and only Oli Flower of SMACC and CODA fame. Like TBI we can split up spinal cord injury into primary and secondary injury. Primary injuries include direct mechanical injury like compression, haematoma, laceration, traction or even complete transection which is thankfully rare. Secondary injuries include local ischaemia that begins at site but extends progressively in both directions (ie the cord level of injury can get worse). There is loss of autoregulation of blood supply and lots of inflammatory stuff. In addition there is often bleeding into the cord with oedema. The assessment of SCI is driven by the ASIA score which is a systematic severity assessment tool that includes pictures and tells you what all the dermatomes and myotomes are so you don’t need to actually carry them all in your brain. It is a useful and at this stage well validated tool for motor prognosis that forms the cornerstone of assessing SCI. It spits out a grade A to E which is unhelpfully the opposite of what you want in your A Levels as a grade A is a complete injury with very low chance of recovery. B is described as sensory incomplete, which again is confusingly named as it suggests that there is an incomplete sensory injury but in reality it means a severe motor injury with preservation of sensory function below the level of injury. C and D are varying degrees of motor preservation below the injury and grade E is normal A further key point to help us speak the language of the spinal surgeons is that of neurological level of injury. The Neurological level of injury = most caudal segment with normal sensory and antigravity (ie 3+ ) motor function. Remember that the neurological level does not usually equal the radiological level as the spinal cord is much shorter than the spinal column. There are a variety of cord syndromes described that are certainly exam worthy and worth knowing about. The central cord syndrome consists of * weakness and sensory loss in the arms>legs, * the useful mnemonic is MUD (motor, upper, distal) * think hyperextension in a grotty neck with pre existing arthritis * the pathophys here is central ischaemia/haematoma The anterior cord syndrome looks like * loss of motor, pain, temp below injury. * can also seen in aortic pathology The brown-seqard syndrome is more notable for teaching anatomy than it is for clinical practice but for completeness look for * ipsilateral loss of motor, proprioception and find touch * contralateral pain and temperature loss Diagnosis and imaging these days is all about CT and MRI. There is still a robust literature in well done plain films for exclusion of c-spine injury in the lower risk patients, but by now I think everyone has just moved to CT. The controversy in ICU at this stage is whether a CT is sufficient. Oh cites a 4% miss rate for CT, ie injuries not seen on CT that will show up on MRI but more importantly only 0.3% actually need an intervention. CT remains better for bones but MRI is brilliant for cord and ligaments. In general, from what I have seen, if the patient has a neck but is unconscious, then they end up getting an MRI, generally several days after the original injury and normal CT c spine. This leads to a prolonged and somewhat hard to quantify decrement in the patient’s care as maintaining spinal precautions is challenging in the ICU patient.