Initial management
- Aim
- To prevent rebleed
- To reduce complications
- Optimizing cerebral perfusion
Complication | Death result | Disability result |
Rebleeding | 6.7 | 0.8 |
Vasospasm | 7.2 | 6.3 |
Hydrocephalus | 0.3 | 1.4 |
Direct effect of SAH | 7.0 | 3.6 |
Intracerebral hemorrhage | 1.0 | 1.0 |
Complications of intracranial surgery | 1.7 | 2.3 |
Other | 2.0 | 1.2 |
Management Strategies (SIX STEPS)
- Urgent Transfer - dedicated neurointensive care unit
- Early Aneurysm repair
- Use of Multimodal neuromonitoring
- Control of ICP & optimisation of cerebral oxygen delivery
- Prevention & Treatment of medical complications
- Prevention, monitoring and aggressive treatment of delayed cerebral ischaemia (DCI)
General management
- Admit to ITU
- Daily Salts
- Hyponatremia
- BD U&E
- Paired osmolality
- 1 hr Neuro orbs
- Bed rest
- SAH precautions: Low external stimulation (restricted visitation, no loud noises)
- I/O charts
- Urine Catheter
- Aggressive fluids
- 2ml/kg/hr of normal saline
- If Haematocrit<40%: 500ml of 5% albumin
- Cardiac function
- ECG
- Echo
- Analgesia
- DVT/PE: AES
- Daily CXR: check for pulmonary edema
- Head elevation: 30% to counter cerebral venous congestion
- Normo/hyperventilation: PaCO2 35-40mmHg
- Use sedation/analgesia
- Hypertonic saline
- Effective in controlling ICP and improve CBF
- EVD: 30% of poor grade SAH improved neurologically after EVD insertion
- Barbiturates
- Reduce Cerebral Metabolism
- Decompressive craniectomy: done for poor grade
Medical
- Improve CBF: CPP=BP-ICP
- Inc. BP
- 3L fluids/day
- Analgesic
- Fentanyl:
- Does not cause histamine release (morphine does)—> causes drop in ICP
- 100mcg IV 2hrsly
- Steroid:
- For H/A and neck pain
- Not given for edema
- Laxatives
- Anti-emetics
- Avoid phenothiazines —> lower seizure threshold
- Ondansetron
- Gastric ulcer protection
- Ranitidine
- One-razored
- Oxygenation
- Intubated: normocarbia + PaO2 >100mmHg
- Non-intubated: 2L O2 Nasal cannula
- Blood pressure :
- Unsecured:
- Keep systolic below 140 mmHg in order to prevent aneurysm rebleeding (Connolly et al., 2012).
- Keep MAP >80mmHg
- To minimise effect of
- Vasospasm
- Cerebral salt wasting
- American heart association for unsecured aneurysm: keep MAP below 110mmHg or SBP 160mmHg
- Do not cause to hypervolemia: causes more complication and does not reduce spasm risk
- Hence use more norad/metaraminol
- Maintain BP range with norad/labetalol
- If drugs used must have arterial line
- Start long acting BP drugs
- Induced Hypertension
- Do not do
- HIMALAIA trial
- Ended early lack of effect on cerebral perfusion and slow recruitment,
- Also has more adverse effects
- Induced hypothermia
- Effective in ICP control but not associated with improved functional outcome
- Summary of targeted temperature management studies
- SAH subarachnoid hemorrhage; TTM targeted temperature management; WFNS World Federation of Neurosurgical Society; DCI delayed cerebral ischemia, mRS modified Ranking scale score; GOS Glasgow outcome scale
Article | Design | Patient | Intervention or exposure | Comparison | Main results |
Muroi C 2008 [39] | Single-center, prospective cohort study | SAH patients with a ventricular catheter for cerebrospinal fluid drainage | (1) 33°C with an endovascular cooling device (2) Barbiturate coma N=7 | No detail described N=8 | There was no significant difference in neurological outcome (GOS >3) at 1year (42.9 vs. 50.0%) |
Anei R 2010 [40] | Single-center Before-after study | Poor-grade SAH patients (WFNS scale >3) | (1) Induction within 24h after the haemorrhage (2) 34°C for 48h with an cooling blanket (3) Rewarming at the rate of 1°C/24h N=16 | No detail described N=19 | There was no significant difference in neurological outcome at 3months |
Badjatia N 2010 [41] | Matched controlled analysis from single-center, prospective cohort | SAH patients with antipyretic resistant fever | 37°C for 14days with a surface cooling device N=40 | Oral acetaminophen w/ or w/o use of a water-circulating blanket N=80 | In multivariate analysis, TTM was associated with better neurological outcome at 12months (79 vs. 54%) |
Kuramatsu JB 2015 [42] | Matched controlled analysis from single-center, prospective cohort | Poor grade SAH patients (Hunt and Hess grade >3 and WFNS scale >3) | (1) Induction within 48h after the haemorrhage (2) 35°C for 7days with an endovascular cooling device (3) Rewarming at the rate of 0.5°C/24h N=12 | Intravenous paracetamol N=24 | Patients in TTM groups had a significantly lower incidence of DCI (50.0 vs. 84.5%) and a tendency to have better functional outcome (mRS <3) at 6months (66.7 vs. 33.3%) |
Choi W 2017 [43] | Single-center, randomized control trial | Poor-grade SAH patients (Hunt and Hess grade >3 and modified Fisher scale >2) | (1) Induction asap after ruptured aneurysmal treatment (2) 34.5°C for 48h with an endovascular cooling device or a surface cooling device (3) Rewarming at the rate of 1°C/24h to 36.5°C N=11 | No detail described N=11 | There was no significant difference in the incidence of DCI (36.3 vs. 45.6%) and favorable neurological outcome (mRS <3) at 3months between two groups (27.3 vs. 9.1%) |
- Tranexamic acid:
- Initiated and stopped within 72 hrs:
- Decrease rate of ultra early rebleed but no significant improvement in long term functional improvement
- Ultra-early tranexamic acid after subarachnoid haemorrhage (ULTRA): a randomised controlled trial
- Bottom line: No clear clinical benefit from TXA use in SAH
- Inclusion:
- ≥18yrs
- Admitted to one of the participating centres
- Symptoms less than 24 hrs
- Non contrast CT confirming SAH
- Exclusion:
- Perimesencephalic bleeding pattern on CT AND
- GCS 13-15 with no loss of consciousness after onset nor focal neurological deficit on admission
- Traumatic SAH pattern on CT
- Ongoing treatment for DVT/PE
- Hypercoagulability disorder
- Pregnancy
- Creatinine >150umol/L
- Imminent death within 24hrs
- Randomization
- Tranexamic acid n480
- Control n475
Lumbar drain
- Wolf et al 2023: EARLYDRAIN
- Bottom line:
- Prophylactic lumbar drainage after aSAH
- Reduced the burden of secondary infarction
- 28.6% in the lumbar drainage group
- 39.9% in the standard of care group
- Reduced the rate of unfavourable outcome (mRS 3-6) at 6 months
- 32.6% in the lumbar drainage group
- 44.8% in the standard of care group
- Inclusion
- aSAH of all clinical grades
- 1st aSAH
- > 18 years
- Pre-morbid modified Rankin Scale score 0 (“no symptoms at all”) or 1 (“no significant disability despite symptoms”)
- Aneurysm treatment performed during the first 48 hours after the initial hemorrhage.
- *Does not need to have HCP for drain insertion
- Exclusion
- Subarachnoid hemorrhage of other than aneurysmal origin
- No hemorrhage visible on initial CT scan (Fisher Grade I / modified Fisher Grade 0)
- Pregnancy
- Concurrent participation in another interventional trial (participation in an observational trial is not an exclusion criterion)
- Life expectancy less than 1 year for other reasons than the current SAH
- Other concomitant severe disease that would confound with treatment
- Other clear contraindication for treatment with a lumbar drain (e.g. absent or compressed basal cisterns on the admission CT)
- Randomization
- Prophylactic lumbar drain (n109)
- A rate of 5 mL per hour was recommended for the first 8 days
- Additional EVD can be used
- Used ICP reading as well
- 1 case of drain site infection
- Standard care (n141)
Endovascular treatment
Techniques
- Constructive
- Thrombosing
- Indication
- Favourable
- Neck- to- dome ratio of 2:1
- Neck size (<5 mm, favourable)
- Location
- Vertebrobasilar circulation
- Age
- Elder
- Unfavourable
- Close relationship to a neighbouring artery (unfavourable).
- Types
- Coiling with Guglielmi detachable coil (GDC) electrolytically detachable coils
- Aim to promote thrombosis of aneurysmal sac to prevent rebleed
- To reduce symptoms of mass effect
- But clipping is superior to coiling for this
- Side effects of Matrix GDC
- Aseptic meningitis
- Communicating HCP
- At the moment not data to suggest Matrix GDC are better than platinum GDC?
- Onxy HD 500 has been used for wide necked or giant ICA aneurysm
- Flow diverting
- With stents, with or without adjunctive coiling,
Feature | Bioactive (Matrix) GDC | Platinum GDC? |
Aim | To induce greater healing response and improved filling volume of a coiled aneurysm --> to improve recurrence rate | 23% of aneurysms recur after coiling |
Mech | Accelerates clot maturation and promotes the development of mature connective tissue and neointimal formation. | |
Material | Polymer used in bioactive coils is polyglycolic/poly-L-lactic acid (PGA/PLLA) | Platinum |
- Destructive
- Trapping --> bypass: distal and proximal arterial interruption
- Clip occlusion
Adjuncts
- Intraluminal stent devices
- Indicated for
- Wide- necked aneurysms
- Risks
- Thromboembolic complications
- Long- term antiplatelet therapy
- Balloon assistance
- Balloon located in parent vessel to help
- Remodelling the aneurysm neck
- Protecting a parent vessel/side branch
- Keep a microcatheter in the aneurysm sac and reduce ‘kickback’ during coil deployment, potentially resulting in a greater packing density.
- Indicated for
- Wide necked aneurysms
- Small aneurysms with a high risk of intraprocedural rupture
- Bifurcation aneurysms,
- Aneurysms with a branch vessel originating from the neck of the aneurysm.
- Intraop use of Somatosensory evoked potentials and motor evoked potentials
- To monitoring techniques, particularly in anesthetized patients.
- When changes occur, the balloon can be deflated.
- Risks
- Thromboembolic complications
- Double- microcatheter technique
- A useful alternative to intraluminal stenting or balloon assistance
- To help achieve a safer and denser coil delivery without the need for antiplatelet therapy.
- Technique
- Two microcatheters are advanced through the guide catheter and into the aneurysm sac.
- Since a single microcatheter may deploy coils that herniate back through a wide neck and into the parent artery, a second microcatheter is also placed in the aneurysm to deploy an additional coil prior to detachment of the first framing coil.
- By doing this, the coils can be thought of as ‘locking’ onto each other if they are deployed sequentially, or ‘weaving’ into each other if they are deployed concurrently.
- One of the coils is then detached. For all subsequent coil deployments, one of the catheters retains a deployed coil that is not detached, thereby acting as a brace since it is connected to the pusher wire.
- Embolization is continued through the available catheter until aneurysm obliteration is complete. This technique increases the coil stability greatly and allows for coiling of some wide- necked aneurysms without stent placement.
Indication
- Elderly pts (>75): significant reduction in morbidity with coiling
- Poor clinical grade
- Inaccessible rupture aneurysm
- Aneurysm configuration
- Dome to neck ratio: >2
- Absolute neck diameter <5mm
- Post circulation of aneurysm
- Patients on Plavix
- Cases where clipping failed or hard to clip
Controversial areas with coiling
- Unruptured aneurysm: esp at M1-M2 j(x) because a branch near the neck
Treatment failures (all figures from Thornton 2002 et al)
- Early failure
- Intraprocedural rupture
- What to do
- Inflate balloon if balloon assisted coiling
- Immediate reverse anticoagulation: 50mg of protamine should be available during the procedure
- Continue pack coils as rapidly as possible
- Insert EVD
- Vasospasm preventing endovascular treatment (< 1.5%)
- Failure to achieve initial obliteration:
- 39% are completely obliterated,
- 46% are ≥ 95% occluded,
- 15% are < 95% occluded 262 .
- Of aneurysms not initially occluded:
- 46% progressively thrombosed
- 26% showed stable neck remnants
- 28% showed enlargement of residual neck
- Late failure
- Failure of partially obliterated aneurysms to go on to thrombose
- Coil compaction
- Enlargement of residual neck
- Recanalization of aneurysm: 1.8% risk
Recurrent SAH after coil
- ISAT: 0.16% at 1 yr (similar rates of rupture between clipping and coiling but the recanalization rate (90% for giant aneurysm and 50% for small aneurysm) is high for coil i.e. Coiling need more retreatment)
- 5% incidence of sAH within 6 months of tx
- follow up
- 6months
- 1.5 yrs
- 3.5 yrs
- Every 5 yrs
- 4x more coil need re treatment vs clip in ISAT
- Try not to use stent assissted coiling in rupture patients as it requires the patient to be on dual antiplatelet therapy
Complications
- Thromboembolism resulting in stroke (4– 5%)
- Intraprocedural aneurysm rupture (7%)
- Coil migration,
- Aneurysm residue (incomplete aneurysm obliteration)
- Modified Raymond and Roy occlusion classification
- Class I: complete obliteration
- Class II: residual neck
- Class III: residual aneurysm
- IIIa: contrast opacification within the coil interstices of a residual aneurysm
- Mascitelli et al 2015: Class IIIa aneurysms
- Were more likely to improve to Class I or II than Class IIIb aneurysms (83.34% vs 14.89%, p<0.001)
- Were also more likely than Class II to improve to Class I (52.78% vs 16.90%, p<0.001)
- IIIb: contrast opacification outside the coil interstices, along the residual aneurysm wall
- Mascitelli et al 2015: Class IIIb aneurysms had a higher retreatment rate (33.87% vs 6.54%, p<0.001) and a trend toward higher subsequent rupture rate (3.23% vs 0.00%, p=0.068).
- Mendenhall et al 2019
- Estimated long-term cumulative durability at 10 years for
- Loss of durability defined as
- Aneurysm re-rupture
- Aneurysm recanalization
- Remnant aneurysm enlargement
Grade | Durability |
1 complete obliteration | 76.9% |
2 residual neck | 70.9% |
3a residual aneurysm contrast opacification within the coil interstices of a residual aneurysm | 67.5% |
3b contrast opacification outside the coil interstices, along the residual aneurysm wall | 47.2% |
- Aneurysm recurrence (20%)
- Factors that influence recurrence after coiling include
- Aneurysm size,
- Aspect ratio,
- Absolute neck width,
- Aneurysmal thrombus,
- Smoking,
- Length of follow- up,
- Familial predisposition,
- Quality of coil packing/ occlusion: Roy Raymond classification
- Presentation with haemorrhage.
- Due to (Dorfer et al 2012)
- Coil compaction
- Aneurysm re-growth
- Fundal migration
- Yu et al 2019 (n97 recurrent aneurysm)
- Risk of rebleeding after recurrence: 6.2% over 6 year
- Gray represents the coiled aneurysm,
- Black represents contrast agent filling.
Type | Definition | Percentage of recurrent aneurysm | Re-Haemorrhage rate if recurrence occurred |
Type I: | Recurrent aneurysm exhibiting pure recanalization inside the packed coils, presenting scattered, small, dot-like filling inside the aneurysm sac on angiographic imaging. | 10.3% | 0% |
Type II: | recurrent aneurysm exhibiting pure coil compaction in the aneurysm neck and sac, presenting aneurysm neck and sac filling without aneurysmal growth. | 20.6% | 0% |
Type III: | a new aneurysm neck formed without significant coil compaction in the initial aneurysm neck and sac. | 16.5% | 1% |
Type IV | a new aneurysm neck formed with significant coil compaction in the initial aneurysm neck and sac. | 16.5% | 1% |
Type V | a new aneurysm sac originated from the initial aneurysm neck, usually with an irregular shape, with or without coil compaction in the initial aneurysm sac. | 36.1% | 4% |
- Aneurysm rebleeding after treatment,
- Contrast nephropathy
- Groin haematoma
Advanced techniques for complex lesions
- There is no standard definition of what constitutes a difficult aneurysm
- Probably
- Any aneurysm that could not be treated with straightforward clipping or coiling to be complex.
- >10 mm in greatest diameter
- Have intraluminal thrombosis,
- Previously coiled, were heavily calcified, or have a fusiform or true blister morphology
- Advanced endovascular techniques
- Indicated
- For some wide- necked aneurysms.
- By ‘jailing’ the coil mass in the aneurysm, the stent wires prevent prolapse of the coils into the parent vessel
- Since endoluminal devices such as stents are prone to thromboembolic complications, patients are typically treated with dual antiplatelet therapy for a period of several months, with at least some form of antiplatelet therapy continuing indefinitely.
- Newer generations of stents are now available with ‘low profile’ configurations (use of a braided design) that may provide
- Superior conformability and parent artery apposition,
- A more reliable and uniform neck bridging than previous neurovascular stents.
- ‘Baby’ stents are also under evaluation for use in the coiling of distal intracranial circulation aneurysm.
- Different vs flow diverter
- Flow diverter less porous so it can change flow. It cannot allow coil to be use after FD deployed
- Flow diverting stents are a relatively new paradigm treatment for brain aneurysms, where intraluminal flow is redirected to the distal parent vessel, rather than into the aneurysm.
- Characterise of flow diverters: (Eg: Pipeline (Medtronic))
- Made of Cobalt-chromium/platinum-tungsten
- Metal Coverage: 30-35%
- Porosity 65-70%
- Which is around 18 pores/mm2
- Mechanism of action of FD: three stages
- Hemodynamic
- Happens immediately after FD placement
- FD exerts a disruption of blood flow into and out of the aneurysm from the parent artery related to the resistance (impedance) created by the mesh.
- Even though contrast opacification and/or washout may be visualized on angiograms, a marked reduction in velocity of blood flow and shear stresses occurs inside the aneurysm
- Thrombus formation
- After haemodynamic stage thrombus stage starts
- Immediate activation of platelets via a complex pathway with progressive formation of a stable thrombus
- Over days to weeks.
- The thrombosis and subsequent occlusion of the aneurysm depends on the
- (Neck) size of the aneurysm,
- FD properties,
- The subject’s blood rheology,
- The platelet response to antiplatelet medication.
- During this stage there may be worsening of local mass effect and/or inflammation leading to exacerbation of prior symptoms such as headaches if previously present.
- Endothelialization:
- Transformation of the amorphous thrombus to its final collagen stage and the simultaneous and progressive endothelialization of the FD driven by CD34+ endothelial progenitor cells that can take several months to years.
- The FD acts as a scaffold for neo-endothelization and remodelling of the artery.
- Time sensitive intra-aneurysmal thrombus transformation to collagen leads to a final reduction in aneurysmal mass.
- Given the metallic properties of the FD, dual antiplatelet therapy (DAPT) is required to reduce the risk of thromboembolism. Aspirin and clopidogrel are the most commonly used antiplatelets
- Some of the best preliminary results for flow diverting stents have been reported for aneurysms in the cavernous and paraclinoid segments of the carotid artery (Brinjikji et al., 2013).
- Redirection of parent vessel flow has been associated with perforator artery ischaemia and this has been the major limitation to the widespread application of this treatment in other vascular territories.
- A device is placed inside the aneurysm sac itself (Woven Endovascular Bridge ‘WEB’ device) which then provides a flow diverting barrier across a wide neck, eventually reconstructing the parent vessel and induces thrombosis and occlusion of the aneurysm.
- Indicated for wide- necked bifurcation aneurysms, such as those at the carotid terminus, basilar apex, and MCA bifurcation with promising preliminary results
- However, there is still limited clinical experience with this device and it remains under investigational regulation in many countries, such as in the United States.
Intracranial stents to assist coiling
Endoluminal flow diversion
Intra saccular flow disruption devices (WEB)
Surgical treatment
Options
Indication
- Younger age
- MCA bifurcation aneurysm
- Giant aneurysm (>20mm): has high recanalization rate with coiling
- Symptoms due to mass effect
- Very small study with 13 patients show that Clip better than coil for PCOM causing CN3 palsy
- Small aneurysm <1.5-2mm
- Higher incidence of intraprocedural rupture with coiling
- Aneurysm not able to be coiled
Brain relaxation: Danger of dec. ICP --> inc. rebleeding
- To avoid excessive retraction
- Hyperventilate
- CSF drainage
- Ventriculostomy
- Lumbar drain
- CSF removed from drain gradually after dura opened
- 10ml per time to a max of 40ml
- Intraop drainage of CSF from cistern
- Diuretics
- Mannitol and/or furosemide
Brain protection during surgery
Cerebral metabolic rate of oxygen consumption (CMRO2)
- Based on neuron using energy for two f(x)
- Maintaining neuronal homeostasis
- Conduction of electrical impulses
- Occlusion of artery causes
- Centre core of ischaemia: cell death
- Penumbra or reversible cell damage
Ways to inc. cerebral ischaemic tolerance
Drugs that mitigate the toxic effects of ischemia without reducing CMRO2
- Ca channel Blocker
- Nimodipine
- Nicardipine
- Flunarizine
- Free radical scavengers
- Superoxide dismutase, dimethylthiourea, lazaroids, barbiturates, Vitamin C
- Mannitol:
- Dec. Bld viscosity --> Transient inc CBF --> re-establish blood flow to compromised parenchyma
Reduction of CMRO2
- Reducing the electrical activity of neurons: titrating these agents to a isoelectric EEG reduces CMRO2 by up to a maximum of ≈ 50%
- Barbiturates:
- Dec. CMRO2
- Rredistribute blood flow to ischemic cortex
- Quench free radicals
- Stabilize cell membranes.
- Isoflurane:
- shorter acting and less myocardial depression than with barbiturates
- Reducing the maintenance energy of neurons: no drugs developed to date can accomplish this, only hypothermia has any effect on this. Below mild hypothermia, extracerebral effects must be monitored
Hypothermia | Core temp | Benefits |
Mild | >33 | Has some beneficial effects. ICP decreased sharply between 36°C and 35°C |
Moderate | 32.5-33 | Used for head injury |
Deep | 18 | Brain can tolerate up to one hour of circuitory arrest |
Profound | <10 | allows several hours of complete ischemia (the clinical usefulness of this has not been substantiated) |
IHAST II Todd 2005:
- RCT WFNS 1-3 SAH clipping
- No overall benefit was demonstrated in the hypothermic group versus normothermic group (67% versus 63% good outcome; p=0.32), with a higher rate of bacteraemia in the hypothermic group (5% versus 3%; p=0.05
- Collateral blood flow can be increased by inducing hypertension (e.g. target MAP 150 mmHg).
Ways to prevent rupture of aneurysm when clipping
- Dissect the aneurysm dome freely so that when clip applied there won't be any tension on aneurysm to cause neck tear.
- Systemic hypotension
- Done at final approach to aneurysm and during manipulation of aneurysm for clipping
- Aim is to
- Reduce turgor of aneurysm facilitating clip closure
- Dec. transmural pressure to reduces rupture
- Danger of hypoxic injury to end organs and brain
- Local hypotension
- Temporary aneurysm clips (specially designed with low closing force to avoid intimal injury) placed on parent vessel
- Do 3 mins clip on and 5 mins clip off. Repeat as many times as required to clip aneurysm
- Proximal ICA can tolerate for an hour
- MCA and the basilar apex tolerate clipping for few minutes
- Can be combined with systemic hypertension to inc. collateral flow
- Risk of
- Ischemia
- For 10-15min of occlusion
- Prevent by giving thiopental 5mg/kg loading then infusion to give burst suppression on EEG
- For >20 min occlusion
- Deep hypothermic circulatory arrest
- Endovascular technique
- Bypass grafting around segment to be occluded
- Intravascular thrombosis --> emboli upon removal of the clip
- Prevent by using 5000U IV heparin
- Circuitry arrest + deep hypothermia
- For pt with large aneurysm containing significant atherosclerosis or thrombus that impedes clip closure and a done that is adherent to vital neural structures
Need post op angiogram to look for (occurs in 20% postoperatively)
- Aneurysmal rest
- Unclipped aneurysm
- Major vessel occlusion
Intraoperative aneurysmal rupture
- 30% rupture rate
- 30% morbidity and mortality rate
- How to detect
- Blown pupil
- Sudden HTN and bradycardia
- How to prevent rupture
- Prevent HTN due to pain
- Insure deep anaesthesia during head-holder pin placement and skin incision
- Consider local anaesthetic (without epinephrine)
- Minimise inc. in transmural pressure
- Reduce MAP
- Dec. shearing forces on aneurysm during dissection by dec. brain retraction
- Radicle removal of sphenoid wing for circle of Willis aneurysm
- Reduce brain volume by mannitol + furosemide, Lumbar drain
- Reduce risk of large tear in aneurysm fundus or neck by
- Sharp dissection
- Try to completely mobilize and inspect aneurysm before clipping
- What to do when it ruptures
- Ventilation with 100% oxygen
- Transient induction of hypotension
- Restoration of intravascular volume
- Administration of thiopental or propofol to produce burst suppression, which reduces CBF and perhaps bleeding and may also produce “brain protection”
- Hyperosmolar therapy in the form of mannitol (0.5-1 g/kg) or hypertonic saline (2 ml/kg of 5% NaCl) to treat brain swelling
- When it can rupture during surgery
- Initial exposure (rare)
- Due to
- Vibration from bone work
- Inc. transmural pressure upon opening dura
- HTN due to pain
- Prevention
- Drop BP
- Control bleeding by placing temp clip across ICA by
- Compressing patient's neck
- Portion of ICA just exiting cavernous sinus
- Resect portions of frontal or temporal lobe to gain access to ICA
- Dissection of the aneurysm
- Tears due to blunt dissection
- Profuse bleed
- Difficult to control
- Use temporary clipping --> return MAP to normal + give neuroprotective agents eg propofol
- Use microsutures to close any portion of tear that extends onto parent vessel
- Laceration due to Sharp dissection
- Tend to be small
- Easily controlled by a single suction
- May respond to gentle tamponade with a small cottonoid
- May shrink down with repeated low current strokes with bipolar
- Clip application: bleeding due to
- Inadequate exposure of aneurysm
- Clip blade may penetrate unseen lobe of aneurysm --> tear in aneurysm --> profuse bleeding
- Remove clip at the first hint
- Try to place temporary clip
- Poor technique clip application
- Place a longer clip parallel to the first one
- Use multiple clips
Recurrence rate 1.5%/4.4 yrs 0.34%/yr
- Clipped anuerysm need to be follow up
- 1 yr
- 5 yr
- Every 10 yr
Types of surgery
- Clipping
- Gold standard
- Across neck of aneurysm
- Too low: occlude parent vessel
- Too high: formation of aneurysmal rest (dogear)
- Can expand and rupture in future
- Incidence of rebleed is 3.7%
- Annual risk of 0.5%
- Need to be follow up and treatment with reop or endovascular technique
- Wrapping/coating
- Last choice when nothing else can be done
- For
- Fusiform basilar trunk aneurysm
- Aneurysm with significant branches arising from the dome or part of the neck is within the cavernous sinus
- Using
- Muscle
- Cotton/muslin (gillingham's series of 60 pts)
- 8.5% rebleeding in <6months
- Annual rebleeding 1.5%/yr (similar to natural hx of doing nothing)
- Plastic resin or other polymer
- Better than the above two techniques but risk of bleed was only slightly lower than the natural hx
- Teflon and fibrin glue
- Ligation
- For giant aneurysm
- Not for non-giant aneurysm: as it can increase risk of thromboembolism
Approaches
Anterior circulation (anterior communicating artery aneurysm, posterior communicating artery aneurysm, middle cerebral artery bifurcation aneurysm)
- Pterional craniotomy
- Allows for exposure of the frontoparietal operculum and opening of the Sylvian fissure to access the circle of Willis.
- 3 pins
- Positioning
- Head rotated 15– 20 degrees away from the side of the aneurysm
- Extended approximately 20 degrees
- Making the malar eminence the high point in the surgical field.
- Head is then lifted above the level of the heart, out of a dependent position
- Skin incision
- Curvilinear skin incision begins at the zygomatic arch 1 cm anterior to the tragus and curves to the midline, just behind the hairline at the widow’s peak.
- Approach
- The scalp is elevated only enough to expose the zygomatic root posterior- inferiorly and the keyhole anteriorly.
- The superficial fat overlying the temporalis fascia should not be entered because the frontalis branch of the facial nerve lies in this tissue plane and can be injured with additional elevation of the scalp flap.
- The temporalis muscle is incised from the zygomatic arch to the superior temporal line along the skin incision, then anteriorly to the keyhole, running 1 cm below the superior temporal line. The temporalis is flapped anteriorly, leaving a cuff of fascia and muscle along the superior temporal line to suture the muscle to during closure for improved cosmetic outcome.
- Next, a burr hole is placed below the superior temporal line posteriorly and a frontal- temporal craniotomy is made using a high- speed drill.
- After bone flap removal, the drill is used to remove the pterion and the lesser wing of the sphenoid medially, all the way to the superior orbital fissure.
- Bone removal is adequate when there is a flat surface over the orbit connecting the anterior and middle cranial fossa.
- The dura is opened with a semicircular incision, hinging anteriorly. Multiple stay sutures flatten the dural flap.
- At the conclusion of the exposure, there should be direct visualization of the frontal and temporal lobes on either side of the Sylvian fissure, permitting an unobstructed view along the dural flap into the carotid cistern
Distal anterior cerebral artery (A2 segment and beyond),
- Bifrontal craniotomy and interhemispheric approach
- Positioning
- Supine with the head in neutral position, or for more distal aneurysms the head can be placed in a lateral position with a 45- degree tilt away from the ground
- Skin incision
- Small portion of craniotomy crosses the midline
- Need to go to one side only
- Right sided approaches, the incision begins at the right zygoma and ends at the contralateral superior temporal line because the craniotomy is eccentric to the right side
- Scalp is then pulled forward to expose supraorbital frontal bone from the ipsilateral superior temporal line to the contralateral glabella.
- The temporalis muscle should be undisturbed.
- Craniotomy
- A rectangular craniotomy is made that is two- thirds in front of the coronal suture and just across the midline to the contralateral side.
- Careful of SSS
- Dural opening
- Semicircular flap with facing the SSS
Upper basilar trunk (basilar apex aneurysm, superior cerebellar artery aneurysm)
- Orbitozygomatic approach + a pterional craniotomy
- Dramatically enhances the standard pterional craniotomy
- Increasing exposure,
- Minimizing retraction,
- Improving manoeuvrability
- Indicated
- Large, giant, or complex anterior circulation aneurysms,
- Aneurysms of the upper basilar trunk.
- Deep bypass procedures
- Benefit from the additional working room
- Removing the orbital walls completely and depressing the eye with the dural flap, along with zygoma resection gives the neurosurgeon a wide sweep of surgical trajectories ranging from supraorbital to trans- Sylvian to pretemporal to subtemporal.
- The surgical trajectory can then be tailored to the exact aneurysm location. A modified orbitozygomatic approach can be used when the zygoma resection would not meaningfully add to the exposure, and it can be left intact
Posterior circulation, such as the posterior inferior cerebellar artery aneurysm,
- Far lateral craniotomy
- Provides an excellent corridor to access most posterior inferior cerebellar artery aneurysms.
- Position
- Modified park- bench OR
- Three- quarter prone position with the lesion side upward.
- The dependent arm hangs over the end of the table, cradled in a padded sling.
- Head position:
- Three manoeuvres are then used to position the head:
- Flexion in the anteroposterior plane until the chin is one finger’s breadth from sternum;
- Rotation 45 degrees away from the side of the lesion, (bringing the nose down toward the floor);
- Lateral flexion 30 degrees down toward the floor.
- Puts the clivus perpendicular to the floor, allowing the neurosurgeon to look down the axis of the vertebral artery.
- The ipsilateral mastoid process becomes the highest point in the operative field.
- The patient’s ipsilateral shoulder is retracted using cloth tape to open the cervical- suboccipital angle.
- Incision
- ‘Hockey- stick’ incision is made beginning in the cervical midline over the C4 spinous process, extending cephalad to the inion, coursing laterally along the superior nuchal line to the mastoid bone, and finishing inferiorly at the mastoid tip.
- The myocutaneous flap is mobilized inferolaterally as a whole to expose the occipital bone and foramen magnum.
- Bony work
- C1 laminectomy is performed all the way laterally to the sulcus arteriosus.
- A suboccipital craniotomy is extended unilaterally from the foramen magnum in the midline, up to the muscle cuff at the level of the transverse sinus, as far laterally as possible, and then back around to the foramen magnum.
- After the craniotomy, the foramen magnum is opened up more widely with rongeurs and a high- speed drill,
- The suboccipital craniotomy is extended past the midline.
- Finally, the posteromedial two- thirds of the occipital condyle are drilled away.
- The anterior extent of the condylar resection is defined either by the condylar emissary vein or by the dura that begins to curve anteromedially, giving a tangential view along this dural plane.
- Condylar resection enables the dural flap reflected against the condyle to be completely flat, and is analogous to the purpose of pterional flattening in a pterional craniotomy.
- Dural opening
- The dural incision curves from the cervical midline, across the circular sinus, to the lateral edge of the craniotomy.
- When completed, the exposure offers a view of the path of the intradural vertebral artery and provides adequate working space in the angle between the lateral medulla and inferior cerebellum
Vertebrobasilar junction aneurysms
- Retrosigmoid craniotomy.
Intracranial surgical technique
Subarachnoid dissection techniques
- By opening up the subarachnoid spaces under high- powered magnification, corridors to the arterial system can be exposed without violating or harming the brain.
- The technique consists of three basic manoeuvres:
- Cutting with microscissors,
- Spreading with bipolar forceps,
- Probing with a slightly curved blunt dissector (such Rhoton #6).
- By opening up these natural cisterns, the frontal and temporal lobes separate, spinal fluid is drained, and the aneurysm can be approached without excessive manipulation or fixed brain retraction.
- As an example,
- Anterior communicating artery aneurysms are approached by first dissecting the Sylvian fissure, then progressing from the carotid to chiasmatic to lamina terminalis cisterns.
- As the surgeon approaches the final dissection of the aneurysm, the orderly sequence exposing afferent arteries, efferent arteries, and the aneurysm neck is often complicated by the presence of the aneurysm dome and difficulty with exposing perforating arteries.
- During this time, temporary clipping may be used for
- Give the surgeon more confidence in the final dissection
- Soften the aneurysm dome
- Allow for better visualization of perforating arteries.
- Barbiturates to achieve electroencephalography (EEG) burst suppression and raising the systemic blood pressure can help to provide protection from ischaemia,
- Surgeon efficiency and highly selective use are the most important aspects of temporary clipping.
- Permanent clipping can take place under complete visualization from start to finish.
- Types of clips:
- Simple clipping,
- Multiple intersecting clips,
- Stacked clips,
- Overlapping clips,
- Permutations of these exist.
- Tandem clipping
- With a fenestrated clip to close the distal aspect of the aneurysm neck, followed by a shorter clip to close the proximal portion of the aneurysm neck not covered by the fenestration is also a very effective technique.
- Exploits a physical characteristic that the force of a fenestrated clip is greatest at the distal end of the clip tines. This allows for an even distribution of force to be applied across the entire aneurysm neck, preventing refilling.
Crisis management,
- Uncontrolled intraoperative bleeding from an aneurysm
- Most feared complications in neurosurgery
- Technique
- Tamponade + suction
- A small piece of cotton can be placed over the rupture site, and pressure and suction can be applied to clear the surgical field of blood.
- Proximal control with temporary clipping,
- Proximal control then slows the bleeding
- Often sufficient to finish dissecting and apply permanent clips.
- Permanent aneurysm clipping.
- After any permanent clip application, whether in the setting of intraoperative rupture or otherwise, the surgeon must spend time inspecting the result.
- Important to check for (Via intraoperative indocyanine green videoangiography)
- Aneurysm occlusion,
- Patency of the parent artery and efferent branches,
- Patency of the perforating arteries,
- If any aneurysm neck is remaining.
Specific aneurysm considerations and locations
Anterior communicating artery aneurysms
- Most challenging.
- The H configuration of A1 and A2 branches must be identified intraoperatively to ensure that none of the branches are compromised on clip application.
- During dissection, consideration must be given to the safe corridors of vascular dissection in relation to the dome of the aneurysm.
- For an anteriorly projecting aneurysm:
- Order of dissection: the outer border of the ipsilateral A1 and ipsilateral A2, then the contralateral A1 and A2.
- For an inferiorly projecting aneurysm,
- Order of dissection: ipsilateral A1 and A2 then contralateral A2 as the contralateral A1 is obscured by the aneurysm fundus.
- Make sure
- Judicious mobilization of the frontal lobes if adherent to the optic chiasm.
- For a superiorly projecting dome
- Order of dissection: both ipsilateral and contralateral A1s to achieve proximal control before identifying both A2s.
- These aneurysms are potentially the most difficult configuration to clip and often require a fenestrated clip around the ipsilateral A2 to avoid leaving a neck remnant.
- On occasions, anterior communicating artery aneurysms require trapping of the whole anterior communicating artery, although this risks sacrifice of the associated perforating arteries.
ICA aneurysms (posterior communicating and anterior choroidal)
- The degree of head rotation during positioning depends on the projection of the aneurysm fundus.
- Posteriorly projecting fundus
- A greater degree of head rotation is required to reveal the neck of the aneurysm from behind the ICA.
- Laterally projecting fundus,
- Care must be taken with temporal lobe mobilization as it may be adherent to the aneurysm and risks premature rupture.
- The anterior choroidal artery branches may be duplicated and closely related to the aneurysm neck.
- It is important to identify and preserve all these branches.
- Preservation of the posterior communicating artery is most important with a foetal configuration which often occurs in association with aneurysm formation.
- ICA bifurcation aneurysms
- Careful identification and dissection of the medial and lateral lenticulostriate perforators is required to avoid incorporation into the aneurysm clip.
- Aneurysm clips at this location are particularly at risk of kinking the parent vessels.
MCA aneurysm clipping
- Requires extensive dissection of the entire fundus as variation in the number of M2 branches is common.
- May require ‘clip reconstruction’ (i.e. use of multiple clips to obliterate the entire neck without compromising the distal branches).
Pericallosal aneurysms
- Are a challenge as the aneurysm fundus will be encountered before the parent vessels are identified and controlled.
- The flow through the pericallosal artery is substantially lower than for the large arteries at the base of the circle of Willis and intraoperative rupture is more easily controlled.
- Image guidance is a useful adjunct in order to plan both the craniotomy and trajectory to the aneurysm
Coiling vs clipping
Ruptured
ISAT (International SAH aneurysmal trial)
- 1 yrs Absolute Risk reduction of poor outcome (modified ranklin score) by 7% for coiling (24%) vs clipping (31%)
- Problems with ISAT
- Only 20% of patients were used in randomisation
- Selection bias
- More nonrandomised pt underwent clip than coil-these weren't part of the trial but you can see that the fallback plan is always clipping.
- Expertise of the surgeon and the interventionalist were not reported and most likely not comparable. i.e. a reg doing a clip vs a consultant doing a coil
- The study group had SAH patients that arent a true representation of the SAH patient at large
- 80% were in good clinical grade Hunt and Hess 1&2
- 93% had small aneurysm (<10mm)
- 97% were from anterior circulation
- Rebleeding rate is high for both groups and might be even higher at more than 1 yr follow up
- Clip 0.05% @ 1 yr (=rebleed <1 yrs - rebleed before tx/total number of patients within the group (1070) )
- Coil 0.15% @ 1 yr
Outcome | ㅤ | Endovascular | Surgical |
Incidence of death or dependence (mRS 3-6) | ㅤ | 23.5% | 30.9% |
Mortality at 1 year | ㅤ | 85 | 105 |
Incidence of re-bleeding (fatality in brackets) | Before treatment | 17 (7) | 28 (19) |
ㅤ | Re-bleed <1 year | 45 (22) | 39 (24) |
ㅤ | Re-bleed >1 year | 7 (2) | 2 (2) |
Re-treatment rate | <1 year | 121 | 32 |
ㅤ | >1 year | 15 | 1 |
Complete occlusion at first follow up angiography | ㅤ | 66% | 82% |
Follow up ISAT 18 yrs
- Higher rebleed in endovascular
- Patients in the endovascular treatment group were more likely to be alive and independent at 10 years than were patients in the neurosurgery group (OR 1·34)
Timing of aneurysmal surgery
- Early surgery <4 days
- Reasons for early
- If successful, eliminate
- es risk of rebleed which is most frequency the period immediately following SAH
- Facilitates treatment of vasospasm which peaks in the incidence between 6-8 days: we can freely hypertense patients
- After securing, we can lavage (tPA or NS) the CSF with EVD to remove vasospasmodic (blood) agents
- Although higher operative mortality but lower patient mortality
- Pt selection for early surgery
- Good medical condition of patient
- Good neurologic condition of patient (Hunt and Hess (H&H) grade ≤ 3)
- Large amounts of SAH, increasing the likelihood and severity of subsequent vasospasm.
- Allowing Hypertension
- Allowing removal of SAH
- Conditions that complicate management in face of unclipped aneurysm: e.g. unstable blood pressure; frequent and/or intractable seizures
- Large clot with mass effect associated with SAH
- Early rebleeding, especially multiple rebleeds
- Indications of imminent rebleeding
- Late surgery >10 days
- Reason for late
- Cerebral oedema/inflammation most severe immediately following SAH
- This necessitates more brain retraction and
- Oedematous brain --> softens brain --> easier to lacerate brain during retraction
- Solid clot have not had time to lyse impedes surgery in early surgery
- Higher risk of intraoperative rupture is higher with early surgery
- Possible increased incidence of vasospasm following early surgery from mechanotrauma to vessels
- Pt selection for Late surgery
- Poor medical condition and/or advanced age of patient
- Poor neurologic condition of patient (H&H grade ≥ 4): controversial.
- Some say the risk of rebleeding and its mortality argues for early surgery even in bad grade patients since denying surgery on clinical grounds may result in withholding treatment in some patients who would do well (54% of H&H grade IV and 24% of H&H grade V patients had favorable outcome in one series).
- Aneurysms difficult to clip because of large size, or difficult location necessitating a lax brain during surgery
- Difficult basilar bifurcation
- Mid-basilar artery aneurysms
- Giant aneurysms
- Significant cerebral edema seen on CT
- Presence of active vasospasm
- Outcomes seem worse when surgery is performed between days 4-10 after SAH (the “vasospastic interval”) than if performed early or late
Signs that point to imminent rupture
- Progressing cranial nerve palsy with 3rd nerve palsy
- Inc. aneurysm size on repeated angiography
- Beating aneurysm sign: different size of aneurysm on different MRA and CTA cuts
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