Neuromonitoring 

Types of IONM  Continuous or signalled  INITIATION  UE: median or ulnar  LE: post tib nerve or peroneal nerve  RECORDING   Transcranial somatosensory cortex  Can use with NM blockade (not sensitive to anesthesia)  Advantages  Reliable, unaffected by anesthetics  Disadvantages  Nerve roots not checked  Delay due to summation  Tests  Dorsal Columns  Loss if:  Impacts dorsal column  Motor EvokedContinue reading “Neuromonitoring “

Physical Examination

Gait  Antalgic  Trendelenberg  Wide-Based Shuffling  Dorsal column involvement (proprioception) – Myelopathy  Steppage/ Lateral Swing  Foot-drop  Assess  Tandem Gait (Heel to Toe walking)  Sensitive for myelopathy  Not specific (hip OA, vestibular dysfunction)  Rhomberg to supplement this test  Heel/ Toe Raises/ walking  >10 – 5/5  4-9 – 4/5  <4 – 3/5   

MRI Sequences  

T1 Weighted Image (T1WI)  The RF pulse spins the protons  T1 reflects the time it takes for that tissue’s protons spine to realign with the magnetic field  Fat  Bright (realigns quick)  Water   Dark  Gadolinium Contrast  bright  T2 Weighted Image (T2WI)  T2 relaxatiton time   RF pulse  Captures differences in spin decay  Fat  Intermediate  Fluid  bright  STIR  Short TauContinue reading “MRI Sequences  “

Spinal Cord and Nerves 

Overview  Terminates as conus medullaris  Adults – L1 inferior border  Neonate – L3  Filum terminale to dorsum of first coccygeal segment  Pia  Arachnoid  Subarachnoid space between pia and arachnoid  CSF  Dura (around the thecal sac)  Pathways (ascending sensory, descending motor)  C spine – central  TLS – progressively peripheral  Long Tracts  A  Peripheral Nerves  C2-7 – exit aboveContinue reading “Spinal Cord and Nerves “

Disc Anatomy  

Function  Spinal motion  Stability  Links adjacent vertebrae  25% of spinal column height  Biomechanics  Converts axial load to hoop stress on the Annulus  Water shifts out of the nucleus pulposis into hoop stress on the annulus  Composition  Hyaline cartilage attaches it to vertebral bodies  Annulus Fibrosis  Outer ring  Type 1 collagen oblique, water, proteoglycan  High collagen: proteoglycan ratio Continue reading “Disc Anatomy  “

Vertebrae Orientation

Overview  33 vertebrae (24 mobile)  7 cervical  12 thoracic  5 lumbar  5 sacral (fused)  4 coccygeal (fused)  Disc Anatomy  Vertebral end plate  1mm fibrocartilage and hyaline cartilage   Increasing ration of fibrocartilage: hyaline  Nucleus Pulposus  Mucoid  70-90% water  Dry weight  65% proteoglycan 15% collagen (Type 2)  Annulus fibrosus  12 lamellae concentric orientation  Collagen fiber in alternatingContinue reading “Vertebrae Orientation”

Spinal Cord Anatomy

Long Tracts (DC ST CT)  DC Dorsal Tract (Posterior)  Proprioceptive  Cross at brainstem  Ipsilateral deficit  Central LE  Sensory enters distally first (distal to proximal) so sacral is central  CT Corticospinal Tract (Lateral) Pyramidal  Motor  Crosses at brainstem  Ipsilateral deficit  Central – UE  Sensory enters distally first so sacral WAS central but then it crossed  STContinue reading “Spinal Cord Anatomy”

Ligamentum Flavum 

Posterior Column  Posterior elements  Vertebral arches  PLC  Ligamentum Flavum  Superior Level  Deep surface of superior lamina  NOT attached to IAP of superior  Inferior Levell  Superficial surface of inferior lamina  DOES attach to SAP of inferior  Prevents hyperflexion, restores resting position  Facet Capsules  Interspinous Ligaments  Supraspinous Ligaments