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assignment 1 description

general, neutral description of article of interest

no referencing needed (but plagiarism is not allowed of course!!)

adding photos:

1. insert –– images and media –– all from wikicommons –– no copyrights

2. wikipedia:public_domain_image_resources eg. flickr –– search images and look for those in public domain (no copyrights) –– upload =Cranioplasty= Add brief introduction on what the operation is about

Relationship between cranioplasty, decompressive cranioectomy, and craniotomy

lead section: 10% of total word count

Categories
Refer to Manual of Style/Medicine-related articles

Etymology
Ancient Greek

Cranio-: cranium

-plasty: moulded, fashioned

done

History
modern use of cranioplasty: arises in 19-20th century due to war use of acrylic in cranioplasty

AUTOGRAFT

Autografts, or autologous grafts, are body tissues taken from the patient. The first successful cranioplasty using an autograft was recorded in 1821, with the bone piece being reinserted into the cranium. The operation achieved partial healing. Subsequently, more studies and operations were carried out with autografts. A successful case of reimplantation of cranial bone was reported by Sir William Macewen in 1885, popularising autografts to be material for cranioplasty. Subsequent operations involved autografts taken from different parts of the patient's body, such as the tibia (thigh bone), scapula (shoulder blade), ilium (hip bone), sternum (chest bone), along with fat tissues and fascia.

aydin:

macewen (1885) and burrell (1888) used original cranium bone to perform the first autograft cranioplasties

muller developed the "sliding flaps" technique of ext tabula

first bone transplantation is technique of Söhr, who used external tabula of cranium without periosteum

high infection and absorption rate (8)

ALLOGRAFT

Allografts are tissues from another individual of the same species. The first use of allografts was reported in 1915 with cadaver cartilage by Morestin. Subsequently, another 32 cases of cranioplasties performed with cadaver cartilage were reported by Gosset in 1916.(sanan) The use of cadaver cartilage was initially favoured, particularly during World War I, due to its malleability and resistance to infection. Its use declined because of its lack of significant calcification and strength.(sanan) Cadaver skull was another type of allograft reported to be used as a cranioplasty material multiple times by Sicard and Dambrin from 1917 to 1919.(3,9,sanan) The material was not favoured due to the high risk of infection with its use. In the 1980s, the use of cadaver allograft disc for filling in small holes received a satisfactory result, and there was a resurgence of the use of cadaver bone.(sanan) However, cadaver bones and allografts in general are not the preferred materials in modern operations.(3,9,sanan)

sanan:

gosset reported another 32 cases of allograft cranioplasty (cadaver cartilage) in 1916

use of cadaver cartilage was initially popular, particularly during wwi as it is resistant to infection and is flexible

however use of cadaver cartilage became unpopular due to its lack of strength and lack of significant calcification

use of cadaver skull by sicard and dambrin: bone was treated with na2co3, xylol, alcohol, and ether and then heat-sterilised

however use of cadaver skull was not favoured as it has a high risk of infection

use of cadaver allograft disc to fill in small holes was satisfactory

although use of cadaver bone had a resurgence in 1980s, it is not the preferred material for surgeons

SYNTHETIC MATERIALS

Various types of synthetic materials have been used throughout the development of cranioplasty.

Currently, cranioplasty

(talk about development of synthetic materials such as PMMA and hydroxyapatite, and what materials are surgeons using now)

pmma, hydroxyapatite, peek, titanium

The use of methyl methacrylate (PMMA) for cranioplasty was being developed since World War II, and the material is used extensively since 1954,(sanan, 8, shah, aydin) when there is a high demand for cranioplasty due to the large amount of injuries. It becomes malleable when an exothermic reaction occurs between its powder form and benzoyl perioxide, allowing it to be moulded to the cranial defect.(1) Advantages of using PMMA is its malleability, low cost, high strength and high durability. Its disadvantages include being vulnerable to infection as bacteria may adhere to its fibrous layer, as well as its brittle nature and having no growth potential.(1)

hydroxyapatite

iacc:

compatible with host due to its mimicking abilities, therefore no immune reactions

has ability to repair itself

(1)

liquid form, forms malleable substance when mixed with liquid sodium phosphate

integrates into surrounding bone as mineral form of bone when fully cured

Hydroxyapatite is ideal for small cranial defects

titanium mesh is placed underneath hydroxyapatite to prevent fractures for operations directly on dura

allows expansion of material, used in paediatric cranioplasty

able to serve as scaffolding of new bones (osteoconductive)

no inflammatory reaction

disadvantages: Brittle, fragile, difficult to contour, cannot bear stress

sanan:

calcium phosphate arranged in hexagonal structure

produced synthetically by sintering

little foreign-body reaction, osteoconductiveness, excellent chemical bonding to bone

brittle and has low tensile strength

porous hydroxyapatite improves bone growth into transplant

aydin:

hexagonal form of calcium phosphate

increases bone repair

min tissue reaction, increased bone repair, good osteointegration

not resistant to mechanical stress, brittle

porous structure allows hydroxyapatite to be more osteointegrated

use with titanium mesh makes hydroxyapatite more stable

patients with hydroxyapatite as material are advised to avoid trauma until total bone repair

shah:

used with titanium mesh for stronger prothesis (better osteointegration)

used in paediatric cranioplasty as it allows expansion of skull

little foreign-body reaction, decent chem bonding to tissue

can be contoured smoothly, excellent cosmetic results

brittle, low tensile strength, high infection rate

not much evidnce for in vivo osteointegration in humans

may break down into fragments over time, lack of lamellar organisation

not to be used for large defects

(1)

PMMA

Poly methyl methacrylate (PMMA) is a material that exists in a powder form. When mixed with benzoyl perioxide, a liquid monomer, an exothermic reaction occurs and the mixture becomes a paste-like material. The shape of the paste can be moulded to the skull defect when it is being cooled down.

advantages of PMMA: can be used for technically challenging areas of the skull, allows plate to be secured next to skull, low cost, strength and durability

disadvantages of PMMA: high infection rate (5-10%) as bacteria may adhere to fibrous area around the plate, plate may break down or be fractured, no growth potential, exothermic reaction, inflammatory reaction

calcium phosphate bone cement (Hydroxyapatite)

liquid form, forms malleable substance when mixed with liquid sodium phosphate

integrates into surrounding bone as mineral form of bone when fully cured

Hydroxyapatite is ideal for small cranial defects

titanium mesh is placed underneath hydroxyapatite to prevent fractures for operations directly on dura

allows expansion of material, used in paediatric cranioplasty

able to serve as scaffolding of new bones (osteoconductive)

no inflammatory reaction

disadvantages: Brittle, fragile, difficult to contour, cannot bear stress

titanium mesh

can be used in isolation and with hydroxyapatite

nonferromagnetic and noncorrosive, no inflammatory reactions

High cost, poor malleability, possible poor cosmesis, loosens over time; image artifact on magnetic resonance images and computed tomographic scans, rendering resolution of adjacent tissue difficult

Iaccarino 2019

Iaccarino C, Kolias AG, Roumy LG, Fountas K, Adeleye AO. Cranioplasty following decompressive craniectomy. Frontiers in Neurology. 2019;10.

PEEK

inert, pliable, mechanically sound

requires in-house sterilization

may increase seroma formation

lower complication rates compared to using autograft and titanium

titanium

can be manufactured as a mesh, a plate, and 3D porous form, has various stiffness and degree of openness

resistant to trauma

high cost

Hydroxyapatite

compatible with host due to its mimicking abilities, therefore no immune reactions

has ability to repair itself

Aydin S, Kucukyuruk B, Abuzayed B, Aydin S, Sanus GZ. Cranioplasty: review of materials and techniques. Journal of neurosciences in rural practice. 2011 Jul;2(2):162-7.

Medical Uses
Sources

Cranioplasty (Piazza & Grady, 2017)

CRANIOPLASTY: COSMETIC OR THERAPEUTIC? Manuel Dujovny, M.D., Albert0 Aviles, B.S., Celso Agner, M.D., Patricia Fernandez, M.D., and Fady T. Charbel, M.D.

When is the operation needed? functional, protection and cosmetic

The operation has its cosmetic value as it restores the normal shape of the head of patients, instead of the presence of a sunken skin flap.

It also has its therapeutic value as the operation provides structure to the skull and protection to the brain from physical damage (piazza, john hopkins). The surgery restores regular cerebrospinal fluid (CSF) and cerebral blood flow dynamics, along with a normal intracranial pressure (piazza, Dujovny). Cranioplasty may improve neurological function in some individuals. Furthermore, it can also reduce the occurrence of headaches caused by injury or a previous surgery. (john hopkins)

timing

The optimal timing of cranioplasty is controversial among literature. Some literature stated that the time between a craniectomy and a cranioplasty is usually between 6 months to a year,(1) while others stated that the two operations should be more than a year apart.(Lee)

The timing of cranioplasty is affected by multiple factors. Sufficient time is required for the recovery of the incision from previous operation(s), as well as to clear any infections (both systemic and cranial).(1) Some findings showed that a greater infection rate is associated with early cranioplasty due to interruption of wound healing,(Yadla) as well as an increased incidence of hydrocephalus.(Malcolm) Contrarily, there is evidence of early cranioplasty limiting complications caused by "syndrome of the trephined", including changes in cerebral blood flow and abnormal cerebrospinal fluid hydrodynamics.(Yadla) Other researchers reported no significant difference in infection rate with different operation timings,(Yadla, Malcolm)

Lee L, Ker J, Quah BL, Chou N, Choy D, Yeo TT. A retrospective analysis and review of an institution's experience with the complications of cranioplasty. British journal of neurosurgery. 2013 Oct 1;27(5):629-35.

Yadla S, Campbell PG, Chitale R, Maltenfort MG, Jabbour P, Sharan AD. Effect of early surgery, material, and method of flap preservation on cranioplasty infections: a systematic review. Neurosurgery. 2011 Apr 1;68(4):1124-30.

there is overall no significant difference in infection rate with different operation timings (Yadla)

there is no sig difference in complication rate with different operation timing, except for early cranioplasties due to hydrocephalus (Malcolm)

early cranioplasty after trauma is associated with a lower risk of extra-axial collections (Malcolm)

No infections, both systemic and cranial, should be present before the operation(1)

cranioplasty timing can be determined (absence of inflammation) with the assistance of various inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate. this can also be determined with serial imaging. (1)

Traditionally accepted that cranioplasties should be delayed for more than a year after the initial surgery to prevent infection (Lee)

Timing of the operation may also vary by the cause of craniectomy, with those due to neoplastic invasion having a earlier cranioplasty, and those due to a1

(1)

optimal timing of cranioplasty differs among cases

multiple factors affect the optimal timing of carrying out the operation

cranioplasty is rarely carried out immediately after cranioectomy, unless cranioectomy is perfomed due to the presence of neoplastic invasion

infections at wound must be cleared before cranioplasty takes place

incisions from previous surgeries must be healed before cranioplasty takes place

patients that have undergone decompressive cranioectomy due to intercranial hypertension would need to have stabilised intercranial pressure and neurological status, as well as show no signs of infection to commence cranioplasty. usually these patients undergo cranioplasty around 3 months after DC.

controversies around the optimal timing for cranioplasty after DC: some say early cranioplasty may lead to an improvement in CSF dynamics and therefore better neurologic recovery; while other studies say that more study is needed to establish relationship between timing of cranioplasty and neurologic outcome

operations after 5-8 weeks may allow tissue layers under skin flap to be separated easier

Timing of cranioplasty depends largely on the indication for craniectomy. Immediate cranioplasty has rare indications and may be performed for craniectomy for neoplastic invasion of cranium. Delayed cranioplasty is usually indicated for removal of bone flap for intracranial infection or medically refractory intracranial hypertension.

Johns Hopkins medicine


 * Protection: In certain places, a cranial defect can leave the brain vulnerable to damage.
 * Function: Cranioplasty may improve neurological function for some patients.
 * Aesthetics: A noticeable skull defect can affect a patient’s appearance and confidence.
 * Headaches: Cranioplasty can reduce headaches due to previous surgery or injury.

link to mental health for cosmetic purposes?

also talk about timing of operation

Piazza M, Grady MS. Cranioplasty. Neurosurgery Clinics. 2017 Apr 1;28(2):257-65.

Dujovny M, Aviles A, Agner C, Fernandez P, Charbel FT. Cranioplasty: cosmetic or therapeutic?. Surgical neurology. 1997 Mar 1;47(3):238-41.

Technique
ie procedure

avoid step-by-step

(1)

CT scans and MRI

antibiotics

patient is positioned on a foam donut or horseshoe head holder

patient is anaesthetised

incision is made following the previous incision

significant blood loss would occur as new blood vessels formed in scar tissues are damaged

scalp is reflected to expose the skull

temporalis muscle should be reflected together with the scalp

soft tissues at the edge of the skull defect are removed and the operation site is cleaned

CSF is drained from the brain to reduce herniation of the brain during the operation

Materials such as PMMA is moulded during the operation. Cranioplasty material is placed on the defect.

standard titanium plate and screws is used to fix autograft or prosthesis to the skull

small holes can be drilled on the bone graft or the prosthesis to prevent accumulation of fluid under the repaired defect

soft tissues, temporalis and scalp are fixed back in place

temporalis muscle may be anchored on material if it is reflected individually

to prevent facial swelling, use of subgaleal drain and wrapping head firmly with dressing

Risks/Complications
bunch of potential risks (http://www.npplweb.com/wjsr/fulltext/5/5) risks on seizure (https://www-sciencedirect-com.ezproxy1.library.usyd.edu.au/science/article/pii/S1059131118305570) risks on bone flap resorption (https://sjtrem.biomedcentral.com/articles/10.1186/s13049-015-0155-6) bone flap resorption: severe bone loss in the autologous graft bone flap resorption

(1)

may occur if flap is devitalised irreversibly or is not in contact with blood vessels

occurs when scar tissue or soft tissue remains on edge of cranial defect before implantation of bone graft

rate of resorption in adults: 0.7-17.4%

risk factors for BFR: comminuted skull fractures, fractures within bone flap, underlying brain contusion

more common in patients of under 18

resorption rates decrease in paediatric patients if operation is carried out early

(4)

resorption rate of bone graft: 3-12% in adults and up to 50% in children

risk factors: young age, bone flap fragmentation, and shunt-dependent hydrocephalus

bone flaps coming from cranial decompression due to trauma has higher resorption rate than other causes

storage method: higher resorption rate when flap is stored in abdominal wall

length of storage

size of bone graft: grafts larger than 70cm2 is more easily resorbed

(15)

resorption occurs more frequently in paediatric patients, particularly if cranioplasty is performed beyond 6 weeks after previous operation

Cranioplasty in children
Lam 2015

examines literature on cranioplasty performed on large-sized cranial defects in children

using autologous bone: 3 methods


 * 1) bone stored in body
 * 2) subcutaneous storage: abdominal pocket, anterolateral thigh, or under scalp
 * 3) potentially be able to nourish osteocytes in flap
 * 4) small children may not have sufficient storage area
 * 5) discomfort reported
 * 6) additional morbidity in storage site
 * 7) some says it is more susceptible to bone resorption
 * 8) cryopreserved bone
 * 9) requires storage facility, logistics may add difficulty to operation
 * 10) freezing process may devitalise bone flap, leading to increased rate of complication
 * 11) high rate of resorption
 * 12) harvested bone flaps

have to consider for high incidence of bone resorption, immature osseous skeleton, and future growth

no significant difference in infection rate between the two storage methods (subcutaneous and cryopreserved)

timing of reconstruction

some said early cranioplasties lead to a lower resorption rate, however others said there is no significant difference

little consensus of ideal way or material for cranioplasty

own bone has high complication rate (resorption)

Lam S, Kuether J, Fong A, Reid R. Cranioplasty for large-sized calvarial defects in the pediatric population: a review. Craniomaxillofacial trauma & reconstruction. 2015 Jun;8(02):159-70.

Josan VA, Sgouros S, Walsh AR, Dover MS, Nishikawa H, Hockley AD. Cranioplasty in children. Child's Nervous System. 2005 Mar 1;21(3):200-4.

Sources to be included on this page

 * 1) title
 * 2) cite using visual referencing

Cranioplasty

Cranioplasty: review of materials and techniques. Journal of neurosciences in rural practice

Risk factors for seizures after cranioplasty

Cranioplasty complications and risk factors associated with bone flap resorption

Cranioplasty in children