(NB: Must Draw Relevant Diagrams from your standard textbooks)
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Transection of Spinal Cord can be of 3 types-
- Complete Transection
- Incomplete Transection
- Hemisection
Complete Transection
- Complete Transection can be due to-
- Gunshot injuries
- Dislocation of spine
- Occlusion of blood vessels
- Most common site of involvement is the mid-thoracic level.
- Effects occur in 3 stages-
- Stage of spinal shock/flaccidity-
- Cessation of all the functions and activity below the level of the section immediately after injury.
- Transection above C-5 is fatal, because of cutting off connection to respiratory centers and muscles.
- Transection between cervical and lumbosacral- both lower limbs paralysed- paraplegia
- Transection below C-5: All four limbs affected- Quadriplegia
- Paralysed muscles become atonic/flaccid
- Areflexia: loss of all reflexes.
- All sensations lost below level of transection
- Transection at T1 level leads to sharp fall in blood pressure.
- Urinary bladder paralysed so retention of urine
- Rectum is paralysed and bowels hypotonic leading to constipation
- Stage of spinal shock/flaccidity-
- Stage of reflex activity/recovery-
- Begins after about 3 weeks
- Smooth muscles are first to regain functional activity.
- Normal micturition and defecation reflex is established
- Sympathetic tone of blood vessels is regained leading to restoration of blood pressure.
- Sweating resumes in skin.
- Further 3-4 weeks later, skeletal muscles regain tone.
- Flexor muscles are first to regain tone leading to ‘paraplegia in flexion’
- Spinal Man- Limbs cannot support the weight of the body.
- Further few weeks later, reflexes resume due to development of denervation hypersensitivity.
- Stage of reflex failure-
- It may occur due to deteriorating conditions due to malnutrition, infection, toxemia, etc.
- Reflexes become more difficult to elicit
- Mass reflex is abolished
- Muscles undergo wasting and become flaccid
Incomplete Transection
- Spinal cord is gravely injured but few tracts are intact
- Effects:-
- Stage of spinal shock
- Stage of reflex activity
- Stage of reflex failure
- Stage of Spinal Shock/flaccidity – Same as stage of spinal shock in complete transection. Write all that.
- Cessation of all the functions and activity below the level of the section immediately after injury.
- Transection above C-5 is fatal, because of cutting off connection to respiratory centers and muscles.
- Transection between cervical and lumbosacral- both lower limbs paralysed- paraplegia
- Transection below C-5: All four limbs affected- Quadriplegia
- Paralysed muscles become atonic/flaccid
- Areflexia: loss of all reflexes.
- All sensations lost below level of transection
- Transection at T1 level leads to sharp fall in blood pressure.
- Urinary bladder paralysed so retention of urine
- Rectum is paralysed and bowels hypotonic leading to constipation.
- Stage of reflex activity/recovery-
- Extensor muscles are first to regain tone leading to a condition called ‘paraplegia in extension’.
- Extensor/Stretch reflexes return first. They include-
- Phillipson Reflex- Extension of opposite limb produced by gentle flexion of one limb
- Extensor Thrust Reflex-
- Patient resting on bed with lower limb passively flexed
- Press his foot upward with palm of hand
- Physiological extensor response is thus elicited which includes-
- Active contraction of quadriceps
- Active contraction of posterior calf muscles
- Straightening of limbs
- Crossed Extensor Reflex-
- Noxious stimuli to sole of one limb given
- Withdrawal flexor reflex is produced
- Forcible extension of opposite limb also takes place
- Mass reflex is not elicited.
- Stage of Reflex Failure– Same as stage of spinal shock in complete transection. Write all that.
- It may occur due to deteriorating conditions due to malnutrition, infection, toxemia, etc.
- Reflexes become more difficult to elicit
- Mass reflex is abolished
- Muscles undergo wasting and become flaccid
Hemisection / Brown-Sequard Syndrome
- Lesion involving one lateral half of spinal cord
- Effects seen in two stages-
- Immediate Effects
- Late Effects
- Immediate Effects:-Same as stage of spinal shock in complete transection.
- Cessation of all the functions and activity below the level of the section immediately after injury.
- Transection above C-5 is fatal, because of cutting off connection to respiratory centers and muscles.
- Transection between cervical and lumbosacral- both lower limbs paralysed- paraplegia
- Transection below C-5: All four limbs affected- Quadriplegia
- Paralysed muscles become atonic/flaccid
- Areflexia: loss of all reflexes.
- All sensations lost below level of transection
- Transection at T1 level leads to sharp fall in blood pressure.
- Urinary bladder paralysed so retention of urine
- Rectum is paralysed and bowels hypotonic leading to constipation
- Late Effects:-
- Motor and Sensory changes after recovery from stage of spinal shock which constitute the “Brown-Sequard Syndrome”
- The changes occur at three levels:-
- At the level of section
- Below the level of section
- Above the level of section
- Changes at the level of hemisection on the same side-
- Sensory Changes-
- Complete anesthesia due to damage to posterior nerve root, posterior horn cells and spinothalamic fibres.
- Motor Changes-
- Complete lower motor neuron type paralysis due to damage to anterior horn cells
- Flaccid paralysis of muscle
- All reflexes are lost
- Muscle power is lost
- Muscles degenerate and undergo wasting due to loss of tone
- Complete and permanent vasomotor paralysis due to damage of lateral horn cells.
- Complete lower motor neuron type paralysis due to damage to anterior horn cells
- Sensory Changes-
- Changes at the level of hemisection on the opposite side-
- Sensory Changes-
- Some loss of pain, temperature and crude touch due to injured spinothalamic tract.
- Sensations carried by uncrossed fibres of tracts of Gall and Burdach like fine touch, tactile localisation, tactile discrimination, sensation of vibration, conscious kinaesthetic sensation and stereognosis not affected.
- Motor Changes–
- Usually not occurs, but if it does its very mild and similar to LMN lesions
- Sensory Changes-
- Changes below the level of hemisection on same side-
- There occurs extensive motor loss but little sensory loss on same side
- Sensory Changes-
- Dissociated sensory loss
- Injury to uncrossed fibres of tracts of Gall and Burdach causes loss of fine touch, tactile localisation, tactile discrimination, sensation of vibration, conscious kinaesthetic sensation and stereognosis.
- No injury to spinothalamic tract so crude touch, pain and temperature sensations are not lost.
- Motor Changes-
- UMN lesion type of paralysis due to injury to pyramidal tracts.
- Increased muscle tone leading to spastic paralysis
- Loss of superficial reflexes
- Exaggeration of deep reflexes
- Positive Babinski’s sign
- Rigidity of limbs
- No degeneration and wasting of muscles.
- Vasomotor Changes-
- Temporary loss of Vasomotor tone due to damage to descending fibres
- Dilatation of blood vessels
- Fall in blood pressure
- Changes below the level of hemisection on the opposite side-
- There occurs extensive sensory loss but little motor loss on the opposite side
- Sensory Changes-
- Dissociated sensory loss occurs
- Loss of crude touch, pain and temperature due to injury to crossed spinothalamic tracts
- No injury to uncrossed tracts of Gall and Burdach so fine touch, tactile localisation, discrimination, vibration, conscious kinaesthetic sensation and stereognosis are retained.
- Motor Changes-
- Usually none
- UMN lesion type paralysis might occur sometimes
- Changes above the level of hemisection-
- A band of hyperaesthesia, i.e. increased cutaneous sensations are present in one or two segments above the level of section on the same side
- Twitching of muscle in upper one or two segments on the same side