A FRCS Neurosurgery station on MedMock, start to finish

Good morning. We'll discuss some clinical scenarios with you, about ten minutes each. The first: you're the neurosurgical registrar on call. The emergency department at a district general hospital refers an 84-year-old man with three weeks of headache, increasing confusion and two falls. He takes apixaban for atrial fibrillation. His GCS is 14, E4 V4 M6, his pupils are equal and reactive, and he has a mild left pronator drift. The CT shows a right-sided convexity collection, mostly hypodense with some mixed density, about 18 millimetres thick, with 7 millimetres of midline shift. How would you deal with the referral?

I'd want some more information first. Is his GCS stable, or has it been falling, and when were his pupils last checked? When did he last take apixaban, and is he on an antiplatelet as well? I'd want his renal function, full blood count, clotting and sodium, because hyponatraemia is common in this group and adds to confusion. Then his background: what he was like before this started, whether he lives independently, his mobility and cognition, his other medical problems, and whether there's a treatment escalation plan or an advance decision. I'd review the images myself through image transfer rather than rely on the verbal report. I'd expect a crescentic collection over the right hemisphere crossing the suture lines. I'd look at the density, because mixed density or septations suggest fresh bleeding into a chronic collection, or membranes, which affects the operation, and I'd check for a collection on the other side. Putting that together, this is a symptomatic right chronic subdural haematoma with mass effect in an anticoagulated man, and he's likely to need drainage. So I'd advise them to stop the apixaban and any antiplatelet and record the time of the last dose, to do hourly neurological observations with clear instructions to call me back if his GCS drops or a pupil changes, and to use mechanical rather than drug thromboprophylaxis. And I'd accept him for transfer to the neurosurgical unit.

He's transferred. His GCS is still 14. His last dose of apixaban was yesterday evening and his renal function is normal. His daughter says that until a month ago he lived alone and managed independently. How would you proceed?

He's stable, so this is urgent but not an emergency. With normal renal function and a high-bleeding-risk procedure, I'd wait at least 48 hours from his last dose of apixaban before operating, as long as he stays stable, and continue his neuro observations. If he deteriorated before then, I'd discuss urgent reversal with haematology rather than wait. Next is consent. He's confused, so I'd formally assess his capacity for this decision. If he has capacity, he consents for himself. If he doesn't, I'd check whether there's a lasting power of attorney for health and welfare; if not, I'd proceed in his best interests under the Mental Capacity Act, involving his daughter, and use the consent form for adults who lack capacity. The operation I'd offer is burr-hole drainage. That can be done under local anaesthetic, with or without sedation, or under general anaesthetic, depending on how cooperative he is and on discussion with the anaesthetist. I'd make two burr holes over the collection, open the dura and the outer membrane, irrigate with warm saline until the fluid runs clear, and leave a subdural drain to gravity, usually removed at about 48 hours. The randomised trial of drains after burr-hole drainage showed that a drain significantly reduced recurrence and mortality at six months. If the collection were heavily septated or largely solid, I'd consider a mini-craniotomy instead. I wouldn't give dexamethasone: the Dex-CSDH trial found fewer favourable functional outcomes at six months than placebo. After surgery: early mobilisation, neuro observations, sodium monitoring, delirium prevention, input from geriatric medicine, and a plan for restarting his anticoagulation made jointly with the team who prescribe it.

The operation goes well and the drain is removed on day two. On day three the nurses call you: he's drowsier, GCS 12, E3 V4 M5, and his left arm is weaker than it was. What's going through your mind, and what do you do?

I'd see him straight away. First, airway, breathing and circulation: oxygen saturations, blood pressure, capillary glucose, and his pupils. The main concerns are a re-collection of the subdural, a new acute haemorrhage, either subdural or intracerebral, and tension pneumocephalus. I'd also think of seizures, meaning a focal seizure or non-convulsive status with post-ictal weakness, and of metabolic causes, particularly hyponatraemia, as well as hypoxia and infection. Delirium is common at his age, but I wouldn't accept it as the explanation until I'd excluded a structural cause. So an urgent CT head, and bloods including sodium and inflammatory markers. If the CT shows a significant re-collection with mass effect, he goes back to theatre for redrainage. If it shows tension pneumocephalus, with air under pressure separating and compressing the frontal lobes, the Mount Fuji sign, I'd give high-flow oxygen and, if he's deteriorating, reopen a burr hole to let the air out. If the CT is no worse than his post-operative scan, I'd have a low threshold for an EEG to look for non-convulsive seizures, correct any sodium abnormality, and keep him under close observation.

Thank you. The second scenario. A 38-year-old woman attends a district general hospital emergency department at eleven at night. She has five days of worsening low back pain with pain radiating down both legs. Since this afternoon she's had to strain to pass urine, and she says it feels different when she wipes. The emergency department registrar phones you. How do you respond?

The single most important instruction is an emergency MRI of her lumbar spine tonight, at her own hospital, not tomorrow morning. Bilateral sciatica with new difficulty voiding and altered saddle sensation is cauda equina syndrome until proven otherwise. The SBNS and BASS standards expect MRI to be available at the presenting hospital around the clock, and the scan doesn't need our agreement first; she should only move if she needs surgery. While that's arranged, I'd ask the registrar to examine and document her lower limb neurology, perianal pinprick sensation, anal tone and voluntary squeeze, and to do a post-void bladder scan, knowing that a normal residual doesn't exclude the diagnosis and mustn't delay the scan. I'd ask about features that point away from a simple disc prolapse: fever, injecting drug use, recent spinal procedures, a history of cancer, weight loss and anticoagulant use, because an epidural abscess, a metastasis or a haematoma changes the plan. She needs adequate analgesia, and I'd ask them to call me as soon as the scan is done and to send me the images.

The MRI shows a large central disc prolapse at L4/5, severely compressing the cauda equina. On examination she has reduced perianal pinprick sensation and reduced anal tone. She can still feel when her bladder is full and can pass urine, but only with straining. Would you operate, and when?

Yes. She has incomplete cauda equina syndrome, CES-I: altered urinary sensation and function, but not yet CES-R, the painless retention with overflow that carries a worse outlook. This is the stage where prompt decompression gives her the best chance of keeping her bladder function, so I'd arrange transfer and operate at the earliest safe opportunity, which for her means tonight rather than the next morning's list. The standards ask us to weigh the extra risk of operating at night, so I'd do it with my consultant informed and an experienced anaesthetic and theatre team. The operation is an L4/5 decompression: a laminectomy and discectomy, with enough bony exposure to take the disc out without retracting the compressed thecal sac, because traction on roots that are already compromised can make her worse. Consent is part of that conversation. The aim is to stop further damage and give the nerves the best chance of recovery, but bladder, bowel and sexual function may not recover fully even after successful surgery. The other risks include a dural tear and CSF leak, infection, bleeding, nerve root injury, recurrent disc prolapse and venous thromboembolism. I'd document her pre-operative neurology, saddle sensation and bladder function carefully, with times.

She asks you, 'Will my bladder and my sex life go back to normal?' What do you say, and what follow-up would you arrange?

I'd sit down with her, ask whether she'd like someone with her, and be honest without being bleak. Something like: 'I can't promise that. The operation takes the pressure off the nerves and gives them the best chance to recover. Because we're operating before you've lost control of your bladder, your chances are better than if we'd waited, and many people recover well. But I have to be honest that a significant number are left with some lasting problems with the bladder, bowel or sex life, and nerves can take many months to recover.' I'd check what she's understood, invite her questions and document the conversation. Afterwards: a trial of voiding with a bladder scan after surgery, early referral to urology or urogynaecology if bladder symptoms persist, pelvic floor physiotherapy, advice on bowel care, an open conversation about sexual function with referral if she wants it, psychological support, review in the spinal clinic, and written information, including where to find patient support.

Finally, suppose her MRI had shown no compression at all. What then?

Then she doesn't have compressive cauda equina syndrome, but her symptoms still need explaining. I'd look at the scan myself to make sure it's adequate and includes the conus. If her signs suggest pathology higher up, such as upper motor neurone signs or a sensory level, I'd image the thoracic or whole spine. I'd consider other causes: a conus or spinal cord lesion, inflammatory or demyelinating disease, urinary retention from opioids, constipation or pain, a primary urological problem, and a functional disorder, which is diagnosed on positive features rather than by exclusion. I'd involve neurology where that's appropriate. If she's safe to go home, she needs clear safety-netting, preferably in writing: what the scan has and hasn't shown, which new symptoms mean she must come straight back, and follow-up arranged for her back pain.

Thank you. That's the end of the station.