Muscle relaxants, back pain, and clinical applications of the spine

Question 1

Muscle paralysis

Answer 1

• Achieved by non-depolarizing or depolarizing (succinylcholine) neuromuscular blockers
• Activity of these drugs monitored by nerve stimulation/muscle twitch
• Reversal of non-depolarizing drugs: CEIs (edrophonium, neostigmine)
• Reversal of succinylcholine: none
• Succinylcholine will be metabolized by pseudocholinesterase (in plasma), only lasts 5 min
• Succinylcholine causes hyperkalemia (contraindicated w/ burn victims)

Question 2

Evolutionary perspective of back pain

Answer 2

• Today our lifestyles are more sedentary, as compared to our active ancestors
• Many humans now have poor posture and sit excessively
• Our unique S-shaped back (to walk upright) puts a lot of stress on the lower back area
• Other social factors that lead to back pain: obesity, depression, the way we carry, lift, walk and run

Question 3

Etiologies of back pain (not serious)

Answer 3

• Muscle or ligament strain
• Disk degeneration/rupture
• Osteoarthritis
• Vertebral fracture/collapse
• Psychosocial factors
• Spinal stenosis (narrowing of intervetebral foramen)

Question 4

Etiologies of back pain (serious) and red flags

Answer 4

• Neoplasm: Hx of cancer, recent fever/chills/weight loss, night pain, worse in supine position
• Infection: Hx of infection, IV drugs, immune suppression, recent fever/chills, night pain, worse in supine position
• Metabolic problems (osteoporosis)
• Neurologic damage: trauma, cauda equina syndrome (saddle anesthesia, bladder/bowel dysfunction, neuro deficits in LE)

Question 5

Most common area of back pain

Answer 5

• In lower back, around the L5-S1 area
• When there is lumbar disc protrusion (or in cervical region), the disc does not affect the nerve exiting above it or the remaining cord
• Instead, the protrusion of a lumbar disc affects the nerve directly below it
• Therefore the disc btwn L4/L5 affects the L5 nerve, and disc btwn L5/S1 affects S1 nerve
• Most pressure on L5 in the slumped sitting position

Question 6

Sx of L/S level nerve compression

Answer 6

• Sciatica: pain in dermatome of sciatic nerve (L4-S3)
• Compression of L4 by L3/L4 disc: extension of quads weak, knee reflex diminished
• Compression of L5 by L4/L5 disc: dorsiflexion of big toe and foot weak, heel walking
• Compression of S1 by L5/S1 disc: plantar flexion of big toe and foot weak, walking on toes, ankle reflex diminished

Question 7

Psychological issues associated w/ back pain

Answer 7

• Depression: less active
• Anxiety
• Hypochondriasis
• Acute remunerative back pain: a person who doesn’t have much motivation to fully recover (receiving disability, ect)

Question 8

Back pain vs leg pain

Answer 8

• Back pain usually due to problems in the spinal structures

- Leg pain usually due to neural compression

Question 9

Complete vs incomplete spinal damage

Answer 9

• Complete means there is no sensation or motor function at and below the level of a SC injury (not salvageable)
• Incomplete: there is some functionality in some part of the body below the level of a SC injury (potentially salvageable)
• Must Rx more aggressively for incomplete to save/improve the remaining functions

Question 10

Types of incomplete SCI

Answer 10

• Central cord syndrome: motor deficit worse in UE than LE (some preserved motor function), and hands have more pronounced motor deficit than arms (good prognosis)
• Brown-sequard syndrome: loss of contralateral STT and ipsilateral motor/light touch/proprioception (one half of SC is transected, good prognosis)
• Anterior cord syndrome: loss of motor/STT on both side, preservation of light touch/proprioception on both sides (poor prognosis)
• Posterior cord syndrome (rare): loss of proprioception and light touch on both sides, motor/STT intact bilaterally, foot slapping gait

Question 11

Cauda equina syndrome

Answer 11

• Due to compression of central canal space (below L1/L2)
• Results in saddle anesthesia, sensorimotor deficits, bladder/bowel retention/incontinence
• Surgical emergency

Question 12

Spinal surgery

Answer 12

• Surgeries will be done for spinal emergencies (cancer, infection, cauda equine syndrome) and the pts that have the correct pathology/medical Hx/social Hx
• Conservative care will solve 99% of spinal problems
• Contraindications to surgery: wrong pathology, social issues (remunerative back problems), psych issues, obesity, metabolic diseases, drug use, prior surgery did not result favorably

Question 13

Reflexes and spinal segments

Answer 13

• C5/6: biceps
• C6: brachioradialis
• C7/8: triceps
• L3/4: patellar
• S1/2: achilles