Int. J. Oral Maxillofac. Surg. 2015; 44: 599–608 http://dx.doi.org/10.1016/j.ijom.2014.09.006, available online at http://www.sciencedirect.com

Clinical Paper Craniofacial Surgery

Custom-made titanium cranioplasty: early and late complications of 151 cranioplasties and review of the literature

L. R. Williams, K. F. Fan, R. P. Bentley Department of Oral and Maxillofacial Surgery, King’s College Hospital, Denmark Hill, London, UK

L. R. Williams, K. F. Fan, R. P. Bentley: Custom-made titanium cranioplasty: early and late complications of 151 cranioplasties and review of the literature. Int. J. Oral Maxillofac. Surg. 2015; 44: 599–608. # 2014 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons.

Abstract. A diverse range of techniques is available for reconstruction of fullthickness calvarial defects and the optimum substrate for cranioplasty remains unproven. During a 9-year period, 149 patients underwent insertion of 151 custommade titanium cranioplasties using the same technique. Data relating to patient demographics, indication for cranioplasty, and site and size of the defect were collected from the clinical records. Patients were followed up in all cases for a mean of 1 year 2 months (range 7 days to 8 years 8 months). Early complications requiring intervention were experienced in 7% and included seroma, haematoma, and continued bleeding necessitating implant removal in one patient. One death occurred at 3 days post-operation due to haemorrhagic stroke. Late self-limiting complications such as seroma were experienced in 19% of patients, however complete failure requiring implant removal was seen in only 4% of cases. Infection was the cause of failure in all cases. A comprehensive literature review was carried out and data abstracted to compare reported failure rates in other techniques of fullthickness cranial reconstruction. This review shows that custom-made patientspecific titanium cranioplasties compare very favourably to the other published techniques and remain a tried and tested option for reconstruction of all sizes of fullthickness calvarial defect.

Full-thickness calvarial defects continue to challenge reconstructive surgeons. Defects of the cranium can arise from a wide range of pathological processes or 0901-5027/050599 + 010

from therapeutic interventions. Reconstruction of these defects is necessary to restore normal craniofacial cosmesis and to protect the otherwise exposed brain

Key words: calvarial reconstruction; cranioplasty; cranial implant. Accepted for publication 3 September 2014 Available online 5 December 2014

from trauma. The ideal cranioplasty technique should produce excellent aesthetics, the ability to withstand direct trauma without failure, have minimal effects on the

# 2014 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons.

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patient in terms of morbidity, and be stable in the long term. Although there are reports of cognitive improvement following cranioplasty and resolution of the socalled ‘syndrome of the trephined’,1–3 currently it is the cosmetic and protective benefits of reconstructing the cranium that are the motivation for undertaking this type of surgery.4 Cranioplasty is one of the oldest known surgical procedures, with archaeological evidence of ancient Incans using gold to reconstruct trephination holes around 3000 BC.5 The earliest written account of cranioplasty dates from 1505 when Ibrahim bin Abdullah, an Ottoman-era military surgeon, advocated the use of a cranial xenograft from a goat or dog.6 In 1561, in Observationes Anatomicae, the Italian Fallopius described cranioplasty with a gold Plate.5 As a result of this long history and as a testament to the complexity of cranial reconstruction, various techniques have been developed to repair these defects using autografts,7–12 allografts,13– 15 and various biomaterials including gold, stainless steel, vitallium, tantalum, titanium, polythene, methylmethacrylate, polyether ether ketones (PEEK), acrylic, ceramics, and bioactive glass, used alone or in combination.5,16–25 There is no ideal technique as each method has its limitations. When autografts are utilized, problems are encountered with satisfactory graft contour and long-term stability, particularly as regards resorption,26–29 along with potential donor site morbidity.10 High infection rates and material failure have been reported with biomaterials.30–33 This study is a retrospective review of early and late complications following cranioplasty in all patients who underwent custom-made titanium plate reconstruction of full-thickness calvarial defects carried out at a tertiary level hospital in London, UK. Materials and method

In this retrospective study, operation records and the laboratory database were used to identify all patients who underwent titanium cranioplasty using a patientspecific custom-made implant at a tertiary level hospital in London between 2001 and 2010. Only patients with full-thickness calvarial defects were included in this study. Clinical records were analysed and data collected on patient demographics, age at operation, indication for cranioplasty, interval between acquisition of defect and reconstruction, length of inpatient stay, length of follow-up, defect site, defect surface area, complications arising

early (defined as occurring during admission) and late complications (defined as arising after discharge). Postoperative follow-up was achieved in all cases; in six cases, the patient’s general practitioner was contacted to identify complications as the hospital records were incomplete. A literature search was undertaken of PubMed and Science Direct using the search terms ‘cranioplasty’, ‘calvarial reconstruction’, ‘cranial reconstruction’, ‘cranial defect’ and ‘calvarial defect’. Returned search articles and their references were used to identify articles reporting complications of cranioplasty. Data were then abstracted from these studies to identify the reported failure rates for the commonly used cranioplasty materials to be used as comparison for the outcome of cranioplasties in the series from the study hospital. Criteria applied to studies for data abstraction were the following: (1) case series reporting the outcome in at least seven patients; (2) publication date during or after 1995; (3) the reported reconstruction method was for full-thickness cranial defects in humans; (4) the failure rate pertaining to each reported method was clearly stated or calculable from the published data. Series of composite reconstruction, i.e. cranioplasty and simultaneous microvascular scalp reconstruction, and case series of allograft cranioplasty were not included in the literature review. The follow-up period and defect size were also recorded if stated or calculable from the data presented in the papers. Manufacture of implant and surgical technique

DICOM data from a fine cut craniofacial computed tomography (CT) scan (1 mm slice, 08 gantry angle) is converted to STL file format to generate a stereolithographic model using rapid prototyping. This model of the defect and surrounding calvarium is invested in plaster and used in a hydraulic press to cold form 0.8-mm thick titanium sheet. The moulded sheet is trimmed to leave a 1 cm margin of titanium to contact the bony edges of the defect. Several holes are drilled at the periphery of the plate to allow screw insertion for fixation, and multiple holes drilled in the central part of the plate to allow extradural fluid collections to drain via vacuum drains. The holes drilled centrally also allow placement of looped PDS sutures hitching the dura to the plate to reduce the extradural space and prevent fluid collections from exerting a space-occupying lesion effect on the brain parenchyma. After polishing,

the cranioplasty plate is anodized and treated with nitric acid. Sterilization is by autoclave prior to insertion into the patient. Surgical access predominantly utilizes existing scars; however if previous incisions have been made in an unfavourable fashion, a bicoronal approach is used to maximize the vascularity of the scalp. The titanium cranioplasty implant is secured with 2-mm titanium screws and the scalp closed in layers with vacuum drains inserted between the scalp and cranioplasty plate. Drains are usually removed at 48 h. A tight head bandage is applied and left in situ until review at 10 days post operation (Fig. 1). Results

For a period of 9 years between August 2001 and August 2010, 149 patients underwent insertion of 151 custom-made titanium cranioplasties for reconstruction of full-thickness calvarial defects. Two patients had bilateral defects reconstructed with individual plates. Seventy-two percent of the patients in this series were male. The average age at operation was 36 years (median 37, mode 56, range 6–78 years). Four of the cranioplasties were carried out as immediate reconstructions following tumour resection; the remainder involved either congenital deformity or delayed reconstruction carried out at an interval following initial craniectomy. The injury date for 13 patients was unknown. For the remaining 133 patients, the average interval between cranial defect and insertion of the cranioplasty was 2 years 1 month (median 1 year, mode 10 months, range 2.5 months to 28 years 9 months). The mean follow-up to discharge was 1 year 2 months (median 5 months, range 7 days to 8 years 8 months). The average length of the inpatient episode was 6.4 days (median 4, mode 4, range 2–121 days). Data on the defect size was accurately calculated using the volume rendering function of the CT scan software (Centricity PACS/AW Suite; GE Healthcare). Due to a change in software used in the hospital we were unable to calculate the accurate surface area for 28 patients. Of the remaining 123 patients, the average defect surface area was 67.5 cm2 (median 65, mode 78.4, range 5.3–173.7 cm2). Very large defects were reconstructed in this group of patients, with 45 implants (36%) being inserted for defects with a surface area greater than 80 cm2 (Table 1). The sites of the defects are illustrated in Fig. 2.

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Fig. 1. Stages in the manufacture and insertion of the titanium cranioplasty: (i) a stereolithographic model is made of the defect. (ii) Hydraulic formed titanium sheet manufactured to reconstruct the defect. (iii) Subperiosteal exposure of the defect. (iv) Cranioplasty plate inserted and secured with titanium screws. Table 1. Defect surface area. Defect surface area, cm 2 Number of defects 0–40 41–80 81–100 >100

32 46 27 18

Indications for cranioplasty are summarized in Table 2. Decompressive craniectomies following trauma, stroke, and intracranial infections and following tumour removal were the most common indication for the original craniectomy (collectively 55%). Infected bone flaps (21%) from previous conventional neurosurgery and following tumour resection involving bone (11%) were the next most common indications, with the remainder of indications comprising post-traumatic defects, post-infection defects, congenital deformity, growing fracture, and deformity as a result of multiple craniotomies. Early complications, defined as occurring before discharge, are summarized in Table 3. One patient died 3 days postoperatively as a result of brainstem haemorrhagic stroke. This patient had undergone bilateral fronto-temporoparietal decompressive craniectomies (defect sizes of 81 cm2 and 105 cm2) following a fall down a flight of stairs. The patient subsequently had a brainstem haemorrhage on the third postoperative day confirmed on CT scan, and life-supportive measures were withdrawn. One patient was complicated by inadequate fit of the implant. This patient underwent immediate

reconstruction following meningioma resection and had a larger defect than was planned for, resulting in the cranioplasty implant not covering the margins of the defect completely. This patient subsequently had a late complication of infection requiring removal of the implant. Significant postoperative bleeding complicated four patients following cranioplasty. One patient had a haematoma that was aspirated under local anaesthetic. One patient was taking aspirin which had not been stopped prior to insertion of the cranioplasty and experienced bleeding 3 days post-operation requiring evacuation of haematoma in theatre under a general anaesthetic. One patient who was normally taking warfarin for previous thromboembolic stroke had been covered with low molecular weight heparin for the procedure. Warfarin was restarted on the first postoperative day and the patient experienced bleeding on day 5 post-operation requiring drainage of haematoma under general anaesthetic in theatre. One further patient experienced prolonged bleeding that required return to theatre and removal of the cranioplasty to evacuate extradural haematoma and obtain haemostasis. This patient subsequently had successful reinsertion of the cranioplasty 2.5 months later without complication. One patient had a seroma which required drainage in theatre. One patient developed sepsis of unknown cause that settled with antibiotics. This patient has not subsequently developed any problems with the

cranioplasty site during a follow-up period of 514 days. The overall early complication rate in this group of patients was 7% with a mortality of 0.67%. Late complications, defined as occurring after discharge, are shown in Table 4. These included seroma, haematoma, and infection. Seroma was noted in 22 patients. This was managed conservatively and settled without intervention in 21 patients. One patient required aspiration of seroma in the outpatient clinic. One patient with no predisposing co-morbidities who underwent reconstruction of a 173.1cm2 defect developed swelling of the cranioplasty site 4 days following discharge from which haematoma was uneventfully aspirated; the patient did not require readmission to hospital. Six of the 149 patients developed late infection and this required cranioplasty removal in all cases. Removal of the cranioplasty took place within a year of placement in four patients. Four of the infections occurred in patients who had had a previous infection at the defect site; three patients had experienced infected craniotomy bone flaps and one patient had had an infection of an acrylic cranioplasty that had been placed at another unit some 4 years previously. Two patients had late infections occurring more than 2 years from insertion. The overall late complication rate in this series was 19%, although the majority of these Table 2. Indication for cranioplasty. Indication

Fig. 2. Sites of the craniectomy defects.

Congenital defect Post tumour resection Post infection Infected bone flap Post decompressive craniectomy Post trauma Growing fracture Post operation deformity

Number of patients 3 17 6 32 82 7 1 1

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Table 3. Early complications of cranioplasty. Number

Notes

Haematoma Cranioplasty removal Infected surgical site

4 1 1

Seroma Death Sepsis of unknown cause Inadequate fit of implant

1 1 1 1

Three required evacuation in theatre Prolonged haemorrhage required removal 2 weeks vancomycin (follow-up 514 days, no further infection) Required drainage in theatre Haemorrhagic stroke 3 days post operation No further complications recorded Bony resection larger than planned

Complication

Table 4. Late complications of cranioplasty. Complication

Number 22 1 6

Seroma Haematoma Infection

Notes All settled by 3 months post operation Required aspiration in clinic All required removal of implant

complications were due to seroma, which settled spontaneously in all but one case. The overall failure rate of cranioplasty in this group of patients was 4%. The characteristics of the late infections group are summarized in Table 5. The most significant complication of cranioplasty is failure, which is either resorption of grafted bone or removal of the prosthesis due to infection or material failure. A comprehensive review of the literature was carried out and data from reported case series were abstracted to compare the results of this case series with other techniques. The analysis of the literature yielded 53 case series that fulfilled the criteria for analysis. The majority of the case series analysed are retrospective, and data regarding defect size and followup were incomplete in several series. Table 6 summarizes the failure rates of these 53 papers.13–15,18–22,24,26–69 Discussion

The technique described has an acceptable overall complication rate, but more critically, this technique has a low long-term failure rate. The surgery is not without significant risk, however, since one patient in this series died in the postoperative period due to haemorrhagic stroke. The incidence of failures (4%) was too low to

allow statistical analysis of the factors involved in failure of this technique for cranioplasty. Previous studies have identified risk factors for a poor outcome and failure in cranioplasty, such as previous irradiation, multiple previous interventions, communication with the paranasal sinuses, inadequate delay between craniectomy and cranioplasty, previous infection, and material for reconstruction.36,38,70 In this series of patients, it is of note that four of the six cases presenting with late infection had a history of previous infection at the cranioplasty site. Four of the patients presenting with late infection had cranial defects as a result of cancer surgery, however none had a history of radiotherapy to the cranioplasty site. In all patients, the paranasal sinuses had either been obliterated prior to cranioplasty or were uninvolved in the defect. These are potential reasons for the low complication rate seen in this series of patients. The choices of cranioplasty material are either an autogenous bone graft or a biomaterial. Analysis of the literature since 1995 shows a wide variety of materials in use (Table 6). The most common bone grafts for cranioplasty are preserved craniectomy bone flaps and split calvarial grafts. Split ribs and demineralized bone matrix lack current case series of significant numbers of patients. A

preserved craniectomy bone flap is an intuitive choice for reconstruction, as the bone flap theoretically provides a perfect fit and contour for the defect as well as offering the potential for revascularization, ultimately becoming vital bone that matches normal skull. In reality the use of preserved craniectomy bone flaps is associated with high failure rates, particularly in paediatric cases.28–30,38,49 Analysis of the published case series since 1995 shows several techniques for preserved bone flap cranioplasty including variations of freezing,27–29,38,47 autoclaving,68 sterilizing with ethylene oxide gas,48 preserving in a subcutaneous pocket,29,56, 57,60 and processing to remove bacteria and viruses then sterilization with gamma irradiation.50 In a series of 54 adults, cryopreservation followed by autoclaving was associated with an infection rate of 25.9%, resulting in failure and graft removal.30 Grant et al. reported resorption requiring reoperation in 50% of a series of 40 children with a cryopreserved bone flap.28 Gooch et al. reported resorption requiring a second operation in 26% in a series of 57 preserved bone flap cranioplasties.27 Seven case series reporting split calvarial grafts since 1995 showed very low complication rates26,35,46,49,52,62,69; only one series of eight patients reported a 12.5% infection and failure rate.52 Split calvarial grafts in adults are principally limited by the quantity of bone available and post-operation contour defects at the reconstruction and donor sites.61,71 Harvesting large areas of outer or inner table inevitably weakens the donor site72 and the diploe¨ is poorly developed in young children precluding bone harvest.46 Intracranial penetration and cerebral damage or damage to the venous sinuses are reported risks of harvest but rarely occur.73 Split rib is uncommonly used, with one specific case series and one other paper reporting split ribs in a larger series of other cranioplasties since 1995,26,66 although isolated reports of extensive defects being repaired with split rib exist.11 No failures were reported in the 15 patients comprising the two series,

Table 5. Characteristics of patients requiring late removal of implant. Age, years 56 26 56 31 71 34

Gender

Immediate or delayed

Previous infection

Indication for craniectomy

Number of previous interventions

Surface area (cm2)

Site of defect

Insertion to removal interval (days)

M M F M F M

Delayed Delayed Immediate Delayed Delayed Delayed

No Yes No Yes Yes Yes

Decompressive Post tumour resection Post tumour resection Infected bone flap Infected bone flap Infected bone flap

1 4 0 3 2 2

96.7 49.3 Unknown 83.3 106.1 43.8

Lateral neurocranium Lateral neurocranium Lateral neurocranium Lateral neurocranium Bifrontal Lateral neurocranium

227 92 51 1010 2817 93

Table 6. Summary of cranioplasty series since 1995. Author and year

Material

Cases, n

Defect size

Follow-up

Significant complications

Akan et al. 201134

PMMA

17

3  3 cm to 16  7 cm

Barone and Jimenez 199735 Blum et al. 199736

Split calvarium

16, paediatric

Not stated

PMMA

75, paediatric

Mean 36 cm 2

Burstein et al. 199937 Chao et al. 200914

HA cement Demineralized bone matrix + polylactic acid/ polyglycolic acid mesh Perforated demineralized allogeneic bone PMMA Cryopreserved bone flap Coraline HA cement/ tantalum mesh Polylactic acid absorbable plates/carbonated apatite bone cement HA cement/tantalum mesh

10 11

1  1 cm to 2  10 cm 6.6–80 cm2 (mean 30.8)

Not stated 13.4–41.8 months (mean 29.3 months)

10

8  6 cm to 11  12.5 cm

2.5–3 years

No failures

23 52 10

Not stated

Not stated

Not stated

34

1  2 cm to 15  15 cm

1–43 months (mean 26 months) 3–60 months (mean 24.4 months)

2 (6.25%) removed (infection) 7 (13.5%) removed (infection) 1 (10%) removed (infection)

8

40–196 cm2 (mean 138)

20 30 7

Chen and Wang 200215 Cheng et al. 200838 Choi et al. 199839 Cohen et al. 2004

40

Durham et al. 200319 Ducic 200218 D’Urso et al. 200041 Eppley 200242 Eppley et al. 200220 Eufinger et al. 200521 Goh et al. 201043 Gooch et al. 200927

17 (23%) removed (12 infections, 3 dislodgements, 2 implant fractures) No failures No failures

No failures

10–156 cm 2 Not stated Not stated

2–33 months (mean 11.4 months) 6 months–3 years Not stated Mean 2.6 years

No failures 1 (3%) removed (infection) No failures

14 143

>150 cm 2 Not stated

1–3 years Not stated

No failures 14 (9.8%) removed (infection)

31 57

6  4 cm to 14  13 cm Not stated

8 months–5 years Minimum 4 months

Not stated

Mean 3.3 years

3 (9.7%) removed (infection) No failures; 16 (26%) required second operation No failures No failures No failures 1 (33%) removal (inadequate bone replacement) No failures

6 months–6 years (mean 4.8 years) 0.5–18 years (mean 6.5 years) 3–16 months (mean 3 months) Mean 46.5 months Mean 52.4 months

3 2 3, paediatric 8, paediatric

Grant et al. 2004

Prefabricated polyethylene (Medpore) Fresh frozen bone flap

40, paediatric

14–147 cm2 (mean 99.4)

Greene et al. 200845

Particulate cranial graft

38, paediatric

5–250 cm2 (mean 66.5)

Hanasono et al. 200924

PEEK

6

6  7 cm to 10  20 cm

Inamasu et al. 201029

Cryopreserved bone flap Subcutaneous stored bone flap

31 38

28

1 (6%) removed (infection); 1 mortality (MI) No failures

3, paediatric

2 (25%) removed (infections)

20 (50%) failures (bone resorption) 1 (3%) failure (resorption) No failures 4 (13%) removed (infection) 2 (5%) removed (infection)

Custom-made titanium cranioplasty

Gosain et al. 200944

HA cement/titanium mesh PMMA HTR (immediate cranioplasty) HTR (delayed cranioplasty) Titanium CAD/CAM manufactured PMMA Preserved autologous bone flap Titanium PMMA Bioactive glass Demineralized bone matrix

36 h to 3 years (mean 1.6 years) 0.79–7.9 years (mean 2.3 years) 3–16 years (mean 10 years)

603

Material

Cases, n

Defect size

Follow-up

Significant complications

Split calvarium

10

5  5 cm to 10  14 cm

Iwama et al. 200347

Frozen bone flap

47

Not stated

Jho et al. 200748

Ethylene oxide gas sterilized bone flap Titanium Bone flap

103

Not stated

148 16, paediatric

Not stated Not stated

Split calvarial graft PMMA Titanium PMMA Tutoplast bone flap Titanium mesh Split calvarium

8, paediatric 3, paediatric 1, paediatric 36 25 12 8

Frozen bone flap In situ moulded PMMA PMMA Polyethylene (Medpore)

91 23 17 9

91–231 cm2 (mean 152)

PMMA

32

Not stated

0.5–22.4 months (mean 6.9 months) 2–16 years (mean 8.2 years)

Cryopreserved bone flap In situ moulded PMMA Custom-made PMMA Titanium mesh Custom-made ceramics High density porous polythene Subcutaneously preserved bone flap Subcutaneously preserved bone flap HTR

54 55 3 77 17 7

Not stated

0.36–12.1 years

4–> 8 cm diameter

75

Mean 9  11 cm

6 months–3 years (mean 18 months) Not stated

52

Not stated

Not stated

2 (4%) removed (infection)

21

Not stated

4 (19%) removed (1 exposure/3 infections)

9 15

Major axis >10 cm 6.25–42.5 cm 2

Pas¸aog˘lu et al. 199660

HA ceramic HA cement + macropore superstructure Subcutaneous bone flaps

27

Not stated

Rogers et al. 201161

Exchange calvarial graft

20, paediatric

5.4–270 cm2 (mean 85.2)

Sahoo et al. 201062

Split calvarial graft Titanium mesh PMMA Cortoss

11 6 5 20

Not stated

0.5–55.4 months (mean 3 months) Not stated 2.2–4.2 years (mean 2.9 years) 6–26 months (mean 10 months) 24 weeks–3.7 years (mean 1.57 years) 18–24 months

Joffe et al. 199922 Josan et al. 200449

Kriegel et al. 200750 Kshettry et al. 201251 Lee et al. 199552 Lee et al. 200953 Lin et al. 201254 Marchac and Greensmith 200833 Matsuno et al. 200630

Mokal and Desai 201155 Morina et al. 201156 Movassaghi et al. 200657 Nassiri et al. 200932 Ono et al. 199958 Pang et al. 200559

Sanus et al. 200863

Not stated Not stated 4.5  3 cm to 8.6  8.6 cm Not stated Not stated

135.9 cm 2

2–43 months (mean 16.9 months) 14–147 months (mean 59.2 months) 1–63 months (mean 14 months) Not stated 3 months–15 years (mean 18 months)

Mean 44 months Mean 15 months Mean 13.2 months 6–36 months (mean 17.8 months) Not stated

18–36 months (mean 24.3 months)

No failures 2 (4%) removed (infection/resorption) 8 (7.8%) removed (infection/resorption) 1 (25 cm 2

Not stated 62

6–38 months 1–6 years (mean 3 years)

2 (19%) required second operation No failures No failures No failures 8 (50%) removed (fragmentation)

No failures; partial resorption 19.3%

No failures No failures; partial resorption 10% 65–150 cm2 (mean 83.3) 5 20

PMMA Allogeneic frozen calvarial bone Autogenous autoclaved bone immediate cranioplasty Split calvarial graft Split rib Conchal cartilage Split calvarium + HA cement HA cement + titanium/ resorbable mesh Vanaclocha et al. 199713 Vanaclocha et al. 199768 Viterbo et al. 199526

Not stated 42 Titanium

8–144 cm2 (mean 49.4) 13 Split rib

Taggard and Menezes 200166 Vahtsevanos et al. 200767

10–58 months (mean 41 months) 10–58 months (mean 41 months) Not stated

2 (5%) removed (infection)

No failures

No failures 25 Custom-made HA prosthesis Staffa et al. 200765

29

Not stated CFRP Saringer et al. 200264

13.5–210 cm2 (mean 120)

1 month–6.8 years (mean 3.3 years) 12–79 months (mean 27 months) 2–48 months (mean 27 months) 0–129 months (mean 30)

No failures

Custom-made titanium cranioplasty

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however limitations of split rib include resorption, a washboard effect at the reconstruction site, difficulty in achieving satisfactory contour, and significant donor site problems including pneumothorax, chest wall deformity, pain, and post-operation atelectasis.10,11,74,75 Demineralized bone matrix reconstructions are under-reported for cranioplasty, with recent publications comprising two small specific case series and one other case series reporting use in three paediatric patients since 1995. One failure was reported in a total of 24 patients across the three series.14,15,44 Chao et al. reported an average of 98% defect healing in a series of 11 young children using demineralized bone and resorbable mesh, however these results were not seen in a series of 10 adults reported by Chen and Wang using demineralized bone matrix and autogenous bone paste, as complete bony infill was observed in only two patients of the series.14,15 Biomaterials offer several advantages over bone grafts. Custom-made implants can perfectly replicate the normal shape of the skull, shorten the operation time, are available in unlimited quantities, and avoid donor site complications. There are, however, several material-specific disadvantages. Several case series have reported high failure rates with hydroxyapatite ceramics, and the use of this material for reconstruction of all but the smallest fullthickness defects is contraindicated.19,31, 39,76 Hydroxyapatite cements were greeted with considerable enthusiasm on their introduction, as the material has been shown to have osseoconductive properties and was thought to eventually be replaced by normal bone; however this has not been demonstrated in large defects.18 Hydroxyapatite cements are prone to fracturing on setting due to pulsations of the underlying dura and on minor impact once set, resulting in ingress of tissue fluid into the material, propagating the fractures and resulting in complete fragmentation of the implant.59,77 Material fragmentation and infection are the most common reasons for failure, with reported failure rates of up to 50%.19,31 Hydroxyapatite ceramics have been associated with a sterile inflammatory tissue reaction leading to thinning of overlying skin and material extrusion.76 Wong et al. reported nine infections and material extrusions in 17 paediatric cases treated using the Norian system for full and partial thickness craniofacial bone repairs.78 Hydroxyapatite cement has been combined with resorbable plates or titanium/tantalum mesh for use

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in large defects and load-bearing areas, although this does not improve results and gives worse failure rates than using a metal implant alone. The addition of titanium mesh or other forms of supporting framework increases the likelihood of material fracture on impact so the logic in using both materials together when metal alone will suffice should be questioned.62 Polymethylmethacrylate (PMMA) is the most widely reported alloplastic material. Thirteen case series of custom-made and in situ moulded PMMA show failure rates of up to 80%.27,30,33,34,36,38,41,43,49,50,53,62,67 PMMA, particularly when moulded in situ, has distinct characteristics that may contribute to the high frequency of failure seen with this material. The quality of the soft tissue envelope surrounding a cranioplasty implant is critical to long-term success; studies have demonstrated that poor quality soft tissues are associated with cranioplasty failure.36,38 The exothermic polymerization reaction of PMMA generates temperatures of up to 110 8C necessitating constant cooling with cold saline during setting to prevent thermal damage to surrounding tissues,77,79 and methylmethacrylate monomer, present in cold cured PMMA, is an irritant.41 These two characteristics of PMMA may adversely affect the overlying skin over time, contributing to the high failure rates seen with PMMA. The titanium cranioplasty, either custom-made or using a mesh system, is reported widely and supported by the largest case series of all biomaterials. Custommade implants are associated with excellent fit to the defect, highly satisfactory cosmetic results, and high patient satisfaction.80 Joffe et al. reported one failure in a series of 148 custom-made cranioplasties, and a multicentre retrospective review of 143 CAD/CAM manufactured titanium cranioplasties showed a 9.8% failure rate.21,22 The principle disadvantage with custom-made titanium implants is cost and the expertise and equipment required in their manufacture: it is estimated that a large cranioplasty from the hospital laboratory costs approximately £1000 to manufacture. More than any other reconstruction, titanium provides an instantly protective reconstruction. One of the patients in this series who had a titanium plate following decompressive craniectomy was subsequently assaulted with an iron bar which dented the cranioplasty but spared the patient neurological injury. It is unlikely any of the other reported biomaterials, or even a normal skull, would have provided such protection to the patient. Favourable results using material such as PEEK, porous polyethylene (Medpore),

carbon fibre reinforced epoxy resin, and bioactive glass for cranioplasty are reported, however these materials are unsupported by large case series with longterm follow-up.20,24,32,42,44,55,64 The optimum method of cranioplasty remains unproven. This case series of 151 titanium cranioplasties with a longterm failure rate of 4% demonstrates that titanium has clear advantages over other biomaterials and provides further evidence that titanium remains a tried and tested solution for full-thickness calvarial defects. Funding

None. Competing interests

None. Ethical approval

Not required. Patient consent

Not required. Acknowledgements. Thanks to Dr Steve Connor, consultant neuroradiologist, for his assistance with the PACS software. References 1. Kuo JR, Wang CC, Chio CC, Cheng TJ. Neurological improvement after cranioplasty—analysis by transcranial Doppler ultrasonography. J Clin Neurosci 2004;11: 486–9. 2. Agner C, Dujovny M, Gaviria M. Neurocognitive assessment before and after cranioplasty. Acta Neurochir (Wien) 2002;144: 1033–40. discussion 1040. 3. Dujovny M, Aviles A, Agner C, Fernandez P, Charbel FT. Cranioplasty: cosmetic or therapeutic? Surg Neurol 1997;47:238–41. 4. Rish BL, Dillon JD, Meiriwsky AM, Caveness WF, Mohr JP, Kistler JP, et al. Cranioplasty: a review of 1030 cases of penetrating head injury. Neurosurgery 1979;4:381–5. 5. Sanan A, Haines SJ. Repairing holes in the head: a history of cranioplasty. Neurosurgery 1997;40:588–603. 6. Aciduman A, Belen D. The earliest document regarding the history of cranioplasty from the Ottoman era. Surg Neurol 2007;68:349–52. discussion 352–3. 7. Guyuron B, Shafron M, Columbi B. Management of extensive and difficult cranial defects. J Neurosurg 1988;69:210–2. 8. Hunter D, Baker S, Sobol SM. Split calvarial grafts in maxillofacial reconstruction. Otolaryngol Head Neck Surg 1990;102:345–50.

9. Bloomquist DS, Feldman GR. The posterior ilium as a donor site for maxillo-facial bone grafting. J Maxillofac Surg 1980;8:60–4. 10. Munro IR, Guyuron B. Split-rib cranioplasty. Ann Plast Surg 1981;7:341–6. 11. Takumi I, Akimoto M. Catcher’s mask cranioplasty for extensive cranial defects in children with an open head trauma: a novel application of partial cranioplasty. Childs Nerv Syst 2008;24:927–32. 12. Zingale A, Albanese V. Cryopreservation of autogenous bone flap in cranial surgical practice: what is the future? A grade B and evidence level 4 meta-analytic study. J Neurosurg Sci 2003;47:137–9. 13. Vanaclocha V, Bazan A, Saiz-Sapena N, Paloma V, Idoate M. Use of frozen cranial vault bone allografts in the repair of extensive cranial bone defects. Acta Neurochir (Wien) 1997;139:653–60. 14. Chao MT, Jiang S, Smith D, DeCesare GE, Cooper GM, Pollack IF, et al. Demineralized bone matrix and resorbable mesh bilaminate cranioplasty: a novel method for reconstruction of large-scale defects in the pediatric calvaria. Plast Reconstr Surg 2009;123: 976–82. 15. Chen TM, Wang HJ. Cranioplasty using allogeneic perforated demineralized bone matrix with autogenous bone paste. Ann Plast Surg 2002;49:272–7. discussion 277–9. 16. Cabraja M, Klein M, Lehmann TN. Longterm results following titanium cranioplasty of large skull defects. Neurosurg Focus 2009;26:E10. 17. Chaco´n-Moya E, Gallegos-Herna´ndez JF, Pin˜a-Cabrales S, Cohn-Zurita F, Gone´-Ferna´ndez A. Cranial vault reconstruction using computer-designed polyetheretherketone (PEEK) implant: case report. Cir Cir 2009;77:437–40. 18. Ducic Y. Titanium mesh and hydroxyapatite cement cranioplasty: a report of 20 cases. J Oral Maxillofac Surg 2002;60:272–6. 19. Durham SR, McComb JG, Levy ML. Correction of large (>25 cm2) cranial defects with ‘reinforced’ hydroxyapatite cement: technique and complications. Neurosurgery 2003;52:842–5. discussion 845. 20. Eppley BL, Kilgo M, Coleman 3rd JJ. Cranial reconstruction with computer-generated hard-tissue replacement patient-matched implants: indications, surgical technique, and long-term follow-up. Plast Reconstr Surg 2002;109:864–71. 21. Eufinger H, Rasche C, Wehmoller M, Schmieder K, Scholz M, Weihe S, et al. CAD/CAM titanium implants for cranioplasty—an evaluation of success and quality of life of 169 consecutive implants with regard to size and location. Int Congr Ser 2005;1281:827–31. 22. Joffe J, Harris M, Kahugu F, Nicoll S, Linney A, Richards R. A prospective study of computer-aided design and manufacture of titanium plate for cranioplasty and its clinical outcome. Br J Neurosurg 1999;13:576–80.

Custom-made titanium cranioplasty 23. Gosain AK. Biomaterials for reconstruction of the cranial vault. Plast Reconstr Surg 2005;116:663–6. 24. Hanasono MM, Goel N, DeMonte F. Calvarial reconstruction with polyetheretherketone implants. Ann Plast Surg 2009;62:653–5. 25. Peltola MJ, Vallitu PK, Vuorinen V, Aho AJ, Puntala A, Aitasalo KM. Novel composite implant in craniofacial bone reconstruction. Eur Arch Otorhinolaryngol 2012;269: 623–8. 26. Viterbo F, Palhares A, Modenese E. Cranioplasty: the autograft option. J Craniofac Surg 1995;6:80–3. 27. Gooch MR, Gin GE, Kenning TJ, German JW. Complications of cranioplasty following decompressive craniectomy: analysis of 62 cases. Neurosurg Focus 2009;26:E9. 28. Grant GA, Jolley M, Ellenbogen RG, Roberts TS, Gruss JR, Loeser JD. Failure of autologous bone-assisted cranioplasty following decompressive craniectomy in children and adolescents. J Neurosurg 2004;100:163–8. 29. Inamasu J, Kuramae T, Nakatsukasa M. Does difference in the storage method of bone flaps after decompressive craniectomy affect the incidence of surgical site infection after cranioplasty? Comparison between subcutaneous pocket and cryopreservation. J Trauma 2010;68:183–7. discussion 187. 30. Matsuno A, Tanaka H, Iwamuro H, Takanashi S, Miyawaki S, Nakashima M, et al. Analyses of the factors influencing bone graft infection after delayed cranioplasty. Acta Neurochir (Wien) 2006;148:535–40. 31. Zins JE, Moreira-Gonzalez A, Papay FA. Use of calcium-based bone cements in the repair of large, full-thickness cranial defects: a caution. Plast Reconstr Surg 2007; 120:1332–42. 32. Nassiri N, Cleary DR, Ueeck BA. Is cranial reconstruction with a hard-tissue replacement patient-matched implant as safe as previously reported? A 3-year experience and review of the literature. J Oral Maxillofac Surg 2009;67:323–7. 33. Marchac D, Greensmith A. Long-term experience with methylmethacrylate cranioplasty in craniofacial surgery. J Plast Reconstr Aesthet Surg 2008;61:744–52. 34. Akan M, Karaca M, Eker G, Karanfil H, Ako¨z T. Is polymethylmethacrylate reliable and practical in full-thickness cranial defect reconstructions? J Craniofac Surg 2011;22: 1236–9. 35. Barone CM, Jimenez DF. Split-thickness calvarial grafts in young children. J Craniofac Surg 1997;8:43–7. 36. Blum KS, Schneider SJ, Rosenthal AD. Methyl methacrylate cranioplasty in children: long-term results. Pediatr Neurosurg 1997;26:33–5. 37. Burstein FD, Cohen SR, Hudgins R, Boydston W, Simms C. The use of hydroxyapatite cement in secondary craniofacial reconstruction. Plast Reconstr Surg 1999; 104:1270–5.

38. Cheng YK, Weng HH, Yang JT, Lee MH, Wang TC, Chang CN. Factors affecting graft infection after cranioplasty. J Clin Neurosci 2008;15:1115–9. 39. Choi SH, Levy ML, McComb JG. A method of cranioplasty using coralline hydroxyapatite. Pediatr Neurosurg 1998;29:324–7. 40. Cohen AJ, Dickerman RD, Schneider SJ. New method of pediatric cranioplasty for skull defect utilizing polylactic acid absorbable plates and carbonated apatite bone cement. J Craniofac Surg 2004;15:469–72. 41. D’Urso PS, Earwaker WJ, Barker TM, Redmond MJ, Thompson RG, Effeney DJ, et al. Custom cranioplasty using stereolithography and acrylic. Br J Plast Surg 2000;53:200–4. 42. Eppley BL. Craniofacial reconstruction with computer-generated HTR patient-matched implants: use in primary bony tumor excision. J Craniofac Surg 2002;13:650–7. 43. Goh RC, Chang CN, Lin CL, Lo LJ. Customised fabricated implants after previous failed cranioplasty. J Plast Reconstr Aesthet Surg 2010;63:1479–84. 44. Gosain AK, Chim H, Arneja JS. Application-specific selection of biomaterials for pediatric craniofacial reconstruction: developing a rational approach to guide clinical use. Plast Reconstr Surg 2009;123:319–30. 45. Greene AK, Mulliken JB, Proctor MR, Rogers GF. Pediatric cranioplasty using particulate calvarial bone graft. Plast Reconstr Surg 2008;122:563–71. 46. Inoue A, Satoh S, Sekiguchi K, Ibuchi Y, Katoh S, Ota K, et al. Cranioplasty with split-thickness calvarial bone. Neurol Med Chir (Tokyo) 1995;35:804–7. 47. Iwama T, Yamada J, Imai S, Shinoda J, Funakoshi T, Sakai N. The use of frozen autogenous bone flaps in delayed cranioplasty revisited. Neurosurgery 2003;52: 591–6. discussion 595–6. 48. Jho DH, Neckrysh S, Hardman J, Charbel FT, Amin-Hanjani S. Ethylene oxide gas sterilization: a simple technique for storing explanted skull bone. Technical note. J Neurosurg 2007;107:440–5. 49. Josan VA, Sgouros S, Walsh AR, Dover MS, Nishikawa H, Hockley AD. Cranioplasty in children. Childs Nerv Syst 2004;21: 200–4. 50. Kriegel RJ, Schaller C, Clusmann H. Cranioplasty for large skull defects with PMMA (polymethylmethacrylate) or Tutoplast processed autogenic bone grafts. Zentralbl Neurochir 2007;68:182–9. 51. Kshettry VR, Hardy S, Weil RJ, Angelov L, Barnett GH. Immediate titanium cranioplasty after debridement and craniectomy for postcraniotomy surgical site infection. Neurosurgery 2012;70:8–14. discussion 14–5. 52. Lee C, Antonyshyn OM, Forrest CR, Cranioplasty:. indications, technique, and early results of autogenous split skull cranial vault reconstruction. J Craniomaxillofac Surg 1995;23:133–42.

607

53. Lee SC, Wu CT, Lee ST, Chen PJ. Cranioplasty using polymethyl methacrylate prostheses. J Clin Neurosci 2009;16:56–63. 54. Lin AY, Kinsella CR, Rottgers SA, Smith DM, Grunwaldt LJ, Cooper GM, et al. Custom porous polyethylene implants for largescale pediatric skull reconstruction: early outcomes. J Craniofac Surg 2012;23:67–70. 55. Mokal NJ, Desai MF. Calvarial reconstruction using high-density porous polyethylene cranial hemispheres. Indian J Plast Surg 2011;44:422–31. 56. Morina A, Kelmendi F, Morina Q, Dragusha S, Ahmeti F, Morina D, et al. Cranioplasty with subcutaneously preserved autologous bone grafts in abdominal wall—experience with 75 cases in a post-war country Kosova. Surg Neurol Int 2011;2:72. 57. Movassaghi K, Ver Halen J, Ganchi P, AminHanjani S, Mesa J, Yaremchuk M. Cranioplasty with subcutaneously preserved autologous bone grafts. Plast Reconstr Surg 2006;117:202–6. 58. Ono I, Tateshita T, Satou M, Sasaki T, Matsumoto M, Kodama N. Treatment of large complex cranial bone defects by using hydroxyapatite ceramic implants. Plast Reconstr Surg 1999;104:339–49. 59. Pang D, Tse HH, Zwienenberg-Lee M, Smith M, Zovickian J. The combined use of hydroxyapatite and bioresorbable plates to repair cranial defects in children. J Neurosurg 2005;102:36–43. 60. Pas¸aog˘lu A, Kurtsoy A, Koc RK, Kontas¸ O, Akdemir H, Oktem IS, et al. Cranioplasty with bone flaps preserved under the scalp. Neurosurg Rev 1996;19:153–6. 61. Rogers GF, Greene AK, Mulliken JB, Proctor MR, Ridgway EB. Exchange cranioplasty using autologous calvarial particulate bone graft effectively repairs large cranial defects. Plast Reconstr Surg 2011;127:1631–42. 62. Sahoo N, Roy ID, Desai AP, Gupta V. Comparative evaluation of autogenous calvarial bone graft and alloplastic materials for secondary reconstruction of cranial defects. J Craniofac Surg 2010;21:79–82. 63. Sanus GZ, Tanriverdi T, Ulu MO, Kafadar AM, Tanriover N, Ozlen F. Use of Cortoss as an alternative material in calvarial defects: the first clinical results in cranioplasty. J Craniofac Surg 2008;19:88–95. 64. Saringer W, No¨bauer-Huhmann I, Knosp E. Cranioplasty with individual carbon fibre reinforced polymere (CFRP) medical grade implants based on CAD/CAM technique. Acta Neurochir (Wien) 2002;144:1193–203. 65. Staffa G, Nataloni A, Compagnone C, Servadei F. Custom made cranioplasty prostheses in porous hydroxy-apatite using 3D design techniques: 7 years experience in 25 patients. Acta Neurochir (Wien) 2007;149:161–70. discussion 170. 66. Taggard DA, Menezes AH. Successful use of rib grafts for cranioplasty in children. Pediatr Neurosurg 2001;34:149–55.

608

Williams et al.

67. Vahtsevanos K, Triaridis S, Patrikidou A, Uttley D, Moore AJ, Bell A, et al. The Atkinson Morley’s Hospital joint neurosurgical–maxillofacial procedures: cranioplasty case series 1985–2003. J Craniomaxillofac Surg 2007;35:336–42. 68. Vanaclocha V, Sa´iz-Sapena N, Garcı´a-Casasola C, De Alava E. Cranioplasty with autogenous autoclaved calvarial bone flap in the cases of tumoural invasion. Acta Neurochir (Wien) 1997;139:970–6. 69. Wiltfang J, Kessler P, Buchfelder M, Merten HA, Neukam FW, Rupprecht S. Reconstruction of skull bone defects using the hydroxyapatite cement with calvarial split transplants. J Oral Maxillofac Surg 2004; 62:29–35. 70. Baumeister S, Peek A, Friedman A, Levin LS, Marcus JR. Management of postneurosurgical bone flap loss caused by infection. Plast Reconstr Surg 2008;122:195e–208e. 71. Frodel Jr JL, Marentette LJ, Quatela VC, Weinstein GS. Calvarial bone graft harvest, Techniques, considerations, and morbidity. Arch Otolaryngol Head Neck Surg 1993;119:17–23.

72. Laure B, Tranquart F, Geais L, Goga D. Evaluation of skull strength following parietal bone graft harvest. Plast Reconstr Surg 2010;126:1492–9. 73. Tessier P, Kawamoto H, Posnick J, Raulo Y, Tulasne JF, Wolfe SA. Complications of harvesting autogenous bone grafts: a group experience of 20,000 cases. Plast Reconstr Surg 2005;116:72S–3S. discussion 92S–4S. 74. Blair GA, Gordon DS, Simpson DA. Cranioplasty in children. Childs Brain 1980;6: 82–91. 75. Marchac D. Split-rib grafts in craniofacial surgery. Plast Reconstr Surg 1982;69:566–7. 76. Moreira-Gonzalez A, Jackson IT, Miyawaki T, Barakat K, DiNick V. Clinical outcome in cranioplasty: critical review in long-term follow-up. J Craniofac Surg 2003;14:144–53. 77. Verret DJ, Ducic Y, Oxford L, Smith J. Hydroxyapatite cement in craniofacial reconstruction. Otolaryngol Head Neck Surg 2005;133:897–9. 78. Wong RK, Gandolfi BM, St-Hilaire H, Wise MW, Moses M. Complications of hydroxyapatite bone cement in secondary pediatric

craniofacial reconstruction. J Craniofac Surg 2011;22:247–51. 79. Costantino PD, Friedman CD, Jones K, Chow LC, Sisson GA. Experimental hydroxyapatite cement cranioplasty. Plast Reconstr Surg 1992;90:174–85. discussion 186–91. 80. Wehmo¨ller M, Weihe S, Rasche C, Scherer P, Eufinger H. CAD/CAM-prefabricated titanium implants for large skull defects—clinical experience with 166 patients from 1994 to 2000. Int Congr Ser 2004;1268:667–72.

Address: Kathy F. Fan Department of Oral and Maxillofacial Surgery King’s College Hospital Denmark Hill London SE5 9RS Tel: +44 20 3299 9000 E-mail: [email protected]