Cranioplasty jc Macquarie Neurosurgery Journal Club
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Transcript of Cranioplasty jc Macquarie Neurosurgery Journal Club
MACQUARIE NEUROSURGERY JOURNAL CLUB 02/02/17
Dr Michael Mulcahy
MACQUARIE NEUROSURGERYJOURNAL CLUB
Stephen Honeybul, David Anthony Morrison, Kwok M. Ho, Christopher R. P. Lind, and
Elizabeth Geelhoed
A randomised controlled trial comparing autologous cranioplasty with custom-made titanium cranioplasty
Journal of Neurosurgery, January 2017, volume 126, pp81-90.
Authors
• Senior author: Stephen Honeybul, neurosurgeon Sir Charles Gairdner Hospital
• David Morrison: biomedical engineer Royal Perth Hospital
• Kwok Ho: intensive care physician Royal Perth Hospital
• Christopher Lind: neurosurgeon Sir Charles Gairdner Hospital and RPH
• Elizabeth Geelhoed, professor of population health, UWA
Disclosures/Funding
•No disclosures
•Partially funded by Western Australian State Health Research Advisory Council ($129 500)
Study Relevance
• Cranioplasty after decompressive craniectomy is performed to restore cerebral protection; for cosmesis; and has been reported to improve neurologic function
• Benefits of patient’s own bone: cheap; biocompatible; radiolucent; ideal contour.
• Disadvantages: high failure rate due to infection or bony resorption
• Titanium is an alloplastic material that has been previously used due to strength and biocompatibility
• Computer-assisted design and manufacturing has made production of custom-made plates viable
Originality
• First RCT comparing bone to titanium
Aim
• To compare the long term aesthetic and functional outcomes, and the cost-effectiveness,
of primary autologous bone versus primary prefabricated titanium cranioplasty.
• Hypothesis: primary titanium cranioplasty improves cerebral protection by avoiding the
frequent problem of bone resorption requiring reoperation, and this will offset the higher
initial outlay cost of titanium plates
Trial Design
• Prospectively registered with ANZCTR (ACTRN12612000353897)
• Interventional randomised controlled trial
• Single centre, single surgeon
• Two arm, parallel group study
• Single Blinded (to patient and relatives)
Trial Design
Eligibility criteria:
• age >18
• decompressive craniectomy + own bone available
Exclusions:
• bone flap damaged or comminuted
• intracranial infection following craniectomy
• penetrating brain injury
Trial Design
Manufacture:
• based on high resolution CT
• rapid protocol 3D model of skull created
• plates manufactured from medical grade titanium, (thickness 0.6-1.0mm)
• patient identification and orientation laser marked on plate
• plate try-fitted on model to ensure smooth contour and unambiguous orientation
• standard steam sterilisation
Trial Design
Surgical procedure:
• all cases performed by S.H.
• detailed operative description
Trial Design
Primary outcome measure:
• implant failure requiring reoperation
• either infected cranioplasty requiring removal of implant or bone flap resorption
Secondary outcome measures:
• adverse events (any time in the 12 months)
• cosmetic and functional outcome (assessed by S.H. and patient/primary carer)
• total hospital costs over 1 year period
Trial Design
Primary Outcome assessment
Trial Design
Secondary Outcome assessment
Trial Design
Statistical Analysis Plan
• sample size calculation: taking p<0.05 as significant, and a power of 80% for the
study, 32 patients in each group to demonstrate a 25% difference
• this was based on S.H. experience: 32% complication rate with autologous
cranioplasty (due to infection or bone resorption) v. <5% complication rate with
titatium cranioplasty
• intention to treat analysis
Results
Results
Results
Primary outcome:
• No infections
Results
Primary outcome:
• 7 (22%) were deemed to have ‘complete failure’ due to bone resorption
Results
Results
Results
Internal Validity
Statistics:
• power calculation was appropriate (80% with p=0.05)
• 25% change in outcome is comparable to the literature of the senior surgeon
• achieved their recruitment target
• sample size calculation seems dubious
Protocol prospectively registered with ANZCTR
• note the change from double to single blinded RCT
• ?Experimenter bias
Internal Validity
Randomisation:
• 6 weeks prior to cranioplasty
• Random number sequence generated by software program
• Randomisation numbers concealed in sequentially numbered sealed envelopes
• Baseline characteristics were similar
Blinding:
• The surgeon was not blinded…he was also the clinical assessor
Subjective outcomes, though no widely used method of measuring cranioplasty success
External Validity
• Representative population
• Relevant inclusion/exclusion criteria
• The trial design is replicable
• Surgical technique is detailed, documented and replicable
• Possible that 12 months is not long enough follow up
• All surgeries performed by a senior neurosurgeon, not usually the case in public hospitals
• Titanium plates not used in MUH
Conclusion
• More revisions in the autologous bone group, but not statistically significant (p=0.053)
• Titanium cranioplasty was associated with better functional and cosmetic outcomes
than autologous bone
• There was no significant difference in health care cost
• No primary infections
• Risk of bias from unblinding of surgeon/assessor
• Overall, thoughtful and well conducted trial, though prone to bias and some limitations
on external validity, so now independent verifiability important