eLearning Flashcards
List the indication for insertion of an ICP monitor
GCS 3-8 after resuscitation and abnormal CT (haematomas, contusions, swelling, herniations, compressed basal cisterns)
Severe TBI (GCS≤8) + normal CT with two or more risk factors for ICH
* Age>40
* Unilateral/bilateral motor decorticate / decerebrate motor posturing
* SBP<90mmHg
List the advantages and disadvantages of intraventricular catheter
Advantage
* More reliable method of assessing ICP
* Allows CSF drainage when ICP is elevated
* CSF sampling possible
* Can be recalibrated in situ
Disadvantages
* Infection risk
* Difficulty inserting if brain swelling
* May become blocked
* Migration
* Must be kept at a fixed reference point (zero to the level of Foramen of Monroe)
Name the anatomical landmark for insertion of ICP monitor
Kocher’s point (1~2cm anterior to the coronal suture in the mid-pupillary line)
List the complications of ICP monitor insertion
Mechanical complications
* Breakage of catheter
* Dislocation of the bolt
* Removal of the catheter
Haemorrhage
Infection
ICP drift
What is normal CSF pressure on LP
8~24 cm
What is normal CSF cell count on LP
No red cells
<5 white cells
What is normal CSF protein count on LP
0.15-0.45 g/L
What is normal CSF glucose count on LP
70% serum glucose
List the most frequent indications for LP
Meningitis
Encephalitis
Subarachnoid haemorrhage
Idiopathic intracranial hypertension
Guillain-Barré syndrome
Multiple sclerosis
List the contraindications for LP
Intracranial neurological disease / raised ICP
Obstruction
Coagulopathy
Infection
When should you do a scan before LP
Focal signs
Papilloedema
Seizure
Impaired consciousness
Immunosuppression
List the complications of an LP
Headache worse on sitting/standing (risk reduced by smaller/blunt needles)
Backache
Infection
Nerve root irritation during the procedure
Venous sinus thrombosis
How is the L3/4 space identified for LP
Imaginary line from tip of the right anterior superior iliac crest perpendicular to the spine
How many samples are taken for LP
At least 3 samples in sterile plain bottles and one in fluoride tube for glucose
* Samples 1 and 3 to microbiology for cell count and culture
* Sample 2 and fluoride to biochemistry for protein and glucose. Wrapped in silver foil if investigating for SAH
* Cytology if investigating for malignancy
What is CSF positive for 14-3-3?
Creutzfeldt-Jakob disease
List the common indications for placement of VAD
Hydrocephalus
Intrathecal administration of chemotherapy
Adjuct to III ventriculostomy (aspirate CSF should there be concerns re ventriculostomy function)
What site is selected for placement of ventricular catheter in EVD
Frontal horn of the right lateral ventricle
What is the site for burr hole in EVD
Kocher’s point: 1~2 cm anterior to coronal suture in mid-pupillary line (3cm from the midline)
Alternatively: 11cm superior and posterior to the nation and 3cm from the midline
Give the anatomical landmark for targets for ventricular catheter
Intersection of the lines from ipsilateral medial canthus and the ipsilateral EAM at 90 degrees to the cortex
List the complications for EVD
Infection
Intraparenchyma/Intraventricular haemorrhage
Extra-ventricular placement
How long can an EVD catheter stay in for
7 days
When would bilateral EVDs be needed
Acute hydrocephalus from III ventricle lesions eg. colloid cysts
What is the depth of the frontal horn of the lateral ventricle from the skull
5cm
Head Injury - what should be clearly and accurately documented on initial assessment
Time and mechanism of injury
On scene GCS
Any delay in achieving adequate ventilation
GCS prior to intubation
Pupil size and reflexes
Head Injury - what blood investigations should be sent for on initial assessment
FBC
Electrolytes
Clotting screen
Sample for transfusion (group and save / cross match)
What should be ordered for head injury patients on warfarin
Prothrombin complex concentrate
Describe the CT appearance of cerebral contusions
Intraparenchymal patchy hyperdensity most commonly in the frontal and temporal lobes
Head injury - what happens when patient is unable to consent for surgery due to consciousness level / capacity
Surgeon should act in the best interest of the patient (consent form 4)
List the indications for urgent surgery in head injury
Extra-axial haematoma (CT mass effect + low consciousness level)
Haemorrhagic contusions
Penetrating injury
Depressed skull fracture
Diffuse axonal injury (ICP monitor)
What is important to ensure when using head clamp for trauma craniotomy
Pins are not placed over any skull fractures
Trauma craniotomy - if the brain is very contused / swells out of the craniotomy following evacuation of the haematoma, what should be done
Dura should not be closed, the bone flap may be left out
What is the anatomical relationship between coronal suture and the motor strip
Motor strip lies 2.5cm behind coronal suture
When inserting an EVD prior to posterior fossa surgery, where should the entry point for the occipital burr hole be
3cm lateral, 6cm cranial to the inion
EVD inserted targeted at the contralateral medial canthus
Describe the positioning and support for frontal burr holes
Position - supine with head in neutral position
Support
* Horseshoe / head ring.
* Pins if craniotomy likely to be needed
Describe the positioning and support for parietal/temporal burr holes
Position - supine with neck rotation and sandbag under the shoulder.
* Avoid heads up positioning in CSDH
Support
* Horseshoe / head ring.
* Pins if craniotomy likely to be needed
Describe the positioning and support for occipital burr holes
Position - prone with some flexion of the head.
Support - head pins
Where should the exit site for subgaleal and extraventricular drains be
5cm away from the wound
How should bleeding from skull addressed
Bone wax
What size blade is used for cruciate durotomy
Size 11
How can post-op haematoma be prevented during surgery
Meticulous haemostasis
Before closing, ask anaesthetist to bring BP up to pre-op levels. (Haemostasis at higher BP)
List the steps to assessing post-op haematoma
ABC
GCS - is this less than the pre-op status?
Wound - is it full, tense/blood seeping through the wound?
Drains - full/blocked?
Lateralising neurology - locates haematoma
How is the age of blood on MRI assessed
Hyper-acute - T1 isodense T2 dark
Acute - T1 bright T2 dark
Sub-acute - T1 bright T2 bright
Chronic - T1 dark T2 dark
What is the appearance of very acute blood with ONGOING active haemorrhage on a CT scan?
Mixed density, mostly hyperintense (lighter) but some areas of hypointensity (darker)
What is the appearance of acute blood that has stopped actively bleeding on a CT scan?
Uniformly hyperintense (lighter) than brain tissue
What is the annulus fibrosis made of
Type 1 collagen
What is the nucleus pulposus made of
95% water, proteoglycans, type 2 collagen
What is the embryological origin of nucleus pulposus
Notocord
Describe where the anterior longitudinal ligament is
Anterior edge of the vertebrae and extends from the skull base to the sacrum
Describe where the posterior longitudinal ligament is
Posterior edge of the vertebral bodies and forms the anterior wall of the spinal canal from C2 to sacrum
What is the cranial extension of the posterior longitudinal ligament
Tectorial membrane
Why is ligament flavum yellow
Rich in elastin
Describe where the ligamentum flavum is
Runs between the laminae, extends from C2 to S1
List the ligaments of the spine
Anterior longitudinal ligament
Posterior longitudinal ligament
Intertransverse ligament
Interspinous ligament
Supraspinous ligament
Ligamentum flavum
What does the posterior longitudinal ligament become at C2 level
Tectorial membrane
List the ligaments at C1/C2
Anterior longitudinal ligament
Posterior longitudinal / tectorial membrane at C2
Cruciate ligament
Transverse ligament
Apical ligament
Alar ligament
Atlantooccipital membrane
Atlantoaxial membrane
Where is the transverse ligaments of C1 and what does it do?
Runs between the inside faces of the C1 lateral masses behind the odontoid peg
Prevents C1/C2 subluxation
Where is the alar ligaments of C1/C2 and what does it do?
Runs from the side of the odontoid peg to the skull base
Resists side to side movements of the head
Moral spine movement - how much can the spine rotate
C1/C2: 45 degrees
C3-T8: 7~10 degrees
Rest: 4 degrees
Moral spine movement - how much can the cervical spine flex/extend
C0/1 15 degrees
C2/3 7 degrees
C5-7 20 degrees
What anatomical landmark can be used to assess the sagittal and coronal balance of spine
C7 plumb line
A plumb line dropped from the middle of C7 vertebrae should pass through the back of the L5/S1 disc space - sagittal balance
Bisect the pelvis - coronal balance
Define the Dennis 3 column theory of spinal stability
Three anatomical columns. If one is damaged, the injury is stable. If two are damaged is unstable.
Anterior - anterior 2/3rds of the vertebral body + ALL
Middle - posterior 1/3rd of vertebral body + PLL
Posterior
* Pedicles
* Lateral mass
* Lamina
* Spinous and transverse processes
Does the C7 vertebrae have a transverse foramen
Yes.
But the vertebral artery does not run through it.
Give the Punjabi and White definition of spinal instability
The loss of ability of the spine under physiological loads to maintain relationships between vertebrae in such a way, that spinal cord or nerve roots are not damaged or irritated and deformity or pain does not develop.
Does lumbar disc protrusion affect the nerve above or below the disc
Below
Do nerve roots exit above or below the pedicle
Below
What does a lateral/posterolateral disc prolapse compress
The transiting nerve root as it appears from the thecal sac and travels down the spinal canal
IE: L5/S1 prolapse will press on the transiting S1 nerve root but spare the exiting L5 root
What will a far-lateral disc prolapse compress
The exiting nerve root within the foramen at the disc level
IE: L5/S1 far-lateral disc will compress the exiting L5 nerve root in the L5/S1 foramen but will not involve the transiting S1 nerve root
95% of lumbar disc prolapse occur at which level? Which age group and gender are most affected?
L4/L5 and L5/S1 level
Most common between 30 and 50
Male preponderance
DIsc prolapse at which level causes foot drop
L4/5 with compression of L5 nerve root
List the symptoms of S1 root compression
Pain + numb form posterior thigh and calf to lateral heel and foot
Diminished ankle jerk
Weak plantar flexion
Limited straight leg raising
List the symptoms of L5 root compression
Pain down postero-lateral thigh, calf, and dorsum of the foot
Numb on the outside of shin, foot, and great toe
Weakness in extensor hallucis longus, foot drop
Restricted straight leg raise
No reflex loss specific to this level
List the symptoms of L4 root compression
Pain down anterior thigh and medial leg
Numb above and below the knee
Weak knee extension
Depressed knee jerk
Straight leg raise may be normal
How much is straight leg raise (Lasegue’s sign) positive in L5/S1 involvement
83%
Reproduces radicular symptoms in the leg
Ankle dorsiflexion can augment the pain
Described the crossed straight leg raise (Fajersztajn test)
SLR on the asymptomatic leg causes pain in the opposite leg
More specific of disc prolapse
What is the femoral stretch test (reverse SLR) positive in
L2, 3, 4 root compression
How to measure urinary retention in CES
Post-void residual volume
Distinguish CES vs conus lesion
Radicular pain
* CES - More severe
* Conus - Less severe
Back pain
* CES - less
* Conus - more
Sensory symptoms
* CES - saddle area, asymmetrical
* Conus - perianal area, symmetrical
Sensory dissociation
* CES - No
* Conus - Common
Motor weakness
* CES - asymmetrical
* Conus - symmetrical
Reflexes
* CES - reduced
* Conus - increased
Sphincter dysfunction
* CES - late
* Conus - early
Bulbocavernosus reflex
* CES - diminished
* Conus - increased
Impotence
* CES - less frequent
* Conus - frequent
List the red flag features in CES
Severe low back pain
Bilateral sciatica
Saddle/genital numbness
Bladder, bowel, sexual dysfunction
Not passing urine for 6 hours
Distinguish CES with retention (CESR) and incomplete CES (CESI)
CESR - painless retention with overflow incontinence
CESI - altered urinary sensation, loss of desire to void, poor stream, strain when passing urine
List the non-surgical treatment approaches to disc herniation
Bed rest (<4 days)
Activity modification - avoid heavy lifting, prolonged sitting, or extremes of lumbar spine movement
NSAIDs, opioids, gabapentin, pregabalin, amitriptyline
Physical therapy
List the surgical treatment approaches to lumbar disc prolapse
Epidural steroid injection (interlaminar, transforaminal, caudal)
Microdiscectomy
List the indications for elective surgery in lumbar disc prolapse
Painful motor deficit
Progressive symptoms
Lack of symptom control
Recurrent disease
List the independent predictors of good outcome following discectomy
No pre-operative co-morbidity
Sciatica <6 months duration
No back pain
Absence of previous surgery
No work-related / compensation issues
Positive SLE without back pain
Crossed leg pain
Radicular pain to the foot
Loss of reflexes
Type of disc herniation
List the complications of lumbar discectomy
CSF leak from dural tear
Neural injury with persistent deficit
Bladder/bowel, sexual dysfunction
Infection, discitis
Residual disc
Recurrent disc herniation (15%)
* Recurrence in the immediate post-operative period is seen in up to 8% cases
Bleeding - epidural haematoma
Peridural fibrosis
Back pain
Abdominal vessel injury (aorta/iliac)
Wrong level surgery
What is the first choice for investigating CES
MRI
In adults, where is cerebral ischaemic injury most marked
Arterial watershed areas eg. borders of anterior and middle cerebral arteries
Summer’s sector of the hippocampus
Basal ganglia
Purkinje cell layer of the cerebellum
What bone is often fractured in extradural haemorrhage
Squamous temporal bone
List the grading for traumatic axonal injury
Grade 1 - axonal damage
Grade 2 - axonal damage + haemorrhagic lesions in corpus callousum
Grade 3 - axonal damage + haemorrhage lesions in corpus callousum and brainstem
