Neurosurgical

Question 1

Risk of post-operative neurological deficit in spinal surgery

Answer 1

0.55% (in a series of 97,000) Visual Loss <0.1%. Poor positioning likely plays a role whilst prone.

Question 2

Ways to monitor perfusion during hypotensive anaesthesia for spinal surgery

Answer 2

• invasive monitoring, - UO 0.5-1.0mL/kg/hr - ABG for metabolic acidosis/ SCvO2. - SSEPs (posterior cord)/ MEPs (anterior cord) useful. Inhaled anaesthetics reduce amplitude and increase latency (dose-dependent, therefore maintain constant MAC)

Question 3

Benefits of regional anaesthesia in orthopaedic surgery

Answer 3

o DVT/PE o Respiratory complications o Post-op pain, chronic pain syndromes. o Blood loss – reduced according to 17 RCTs (? By reducing venous pressure)

Question 4

Timing of DVT prophylaxis around orthopaedic procedures? What if neuraxial blockade employed?

Answer 4

o Administration of LMWH 6/24 post-op is effective and does not increase bleeding (Waiting 24/24 is less effective) o Continue 10 days at least, 28-35 if high risk. o Beware use of regional techniques:  LMWH→ Neuraxial block needs >12/24  Therapeutic LMWH → Neuraxial needs >24/24  LMWH→ Epidural removal needs >12/24, then wait >2/24 for next dose

Question 5

Diagnosis of fat embolism syndrome

Answer 5

Diagnostic criteria: Gurd’s Diagnostic Criteria Major features – at least one - Respiratory insufficiency - Cerebral involvement - Petechial Rash Minor features - at least four - Fever - Tachycardia - Jaundice - Renal - Retinal change Lab features - Fat microglobulinaemia (reqd) - Anaemia - Thrombocytopenia - ↑ ESR

Question 6

Bone-Cement Implantation syndrome grades

Answer 6

Grade 1 SpO2 20% Grade 2 SpO2 88% or Unexpected LOC Grade 3 Cardiovascular collapse requiring CPR

Question 7

Anaesthetic techniques to prevent Bone-Cement Implantation syndrome

Answer 7

 Identification of risk  Optimisation of cardiovascular status  Reducing volatile concentration  Advising surgeons to use surgical techniques to reduce risk: • Cement-free prosthesis • Pressure venting hole • Thorough lavage of medullary canal • Bone-vacuuming  Intraoperative TOE

Question 8

Management of Bone-Cement Implantation syndrome

Answer 8

 Self-limiting – lasts 24 hours  FiO2 to 100%  Treat as for RVF: • Inodilators (dobutamine/ milrinone) • IV therapy • CO monitoring (TOE/ PiCCO/ Swan)

Question 9

Nerve supply to hip

Answer 9

obturator, inferior gluteal, superior gluteal.

Question 10

Nerve supply to knee

Answer 10

tibial nerve, common peroneal nerve, posterior branch of obturator, femoral nerve