Custom made bioceramic implants in complex and large cranial reconstruction: A two-year follow-up

Management of infections complicating the orbitocranial approaches: Report of two cases and review of literature

BACKGROUND

The orbitocranial approaches are now indispensible for treating lesions of the skull base, providing access to lesions in the anterior and middle cranial fossae, as well as the upper clivus and anterior brainstem. The management of infectious complications of the orbitocranial approaches, however, has evaded the literature.

CASE DESCRIPTION

We present two cases of patients who underwent orbitocranial approach whose clinical course was complicated by wound infection and osteomyelitis. One patient was treated with antibiotics and then had a custom implant placed for cranioplasty. The other case was managed with removal of bone and wire-mesh cranioplasty.

CONCLUSION

Management of orbitocraniotomy infections can be difficult due to the complex geometry of the flap and to cosmetic considerations. Once the infection involves the bone, the bone can be replaced after cleaning or discarded and a cranioplasty performed. Cranioplasty can be performed with wire-mesh or a custom implant made by computer-assisted modeling.

Custom-Made Computer-Aided-Design/Computer-Aided-Manufacturing Biphasic Calcium-Phosphate Scaffold for Augmentation of an Atrophic Mandibular Anterior Ridge

This report documents the clinical, radiographic, and histologic outcome of a custom-made computer-aided-design/computer-aided-manufactured (CAD/CAM) scaffold used for the alveolar ridge augmentation of a severely atrophic anterior mandible. Computed tomographic (CT) images of an atrophic anterior mandible were acquired and modified into a 3-dimensional (3D) reconstruction model; this was transferred to a CAD program, where a custom-made scaffold was designed. CAM software generated a set of tool-paths for the manufacture of the scaffold on a computer-numerical-control milling machine into the exact shape of the 3D design. A custom-made scaffold was milled from a synthetic micromacroporous biphasic calcium phosphate (BCP) block. The scaffold closely matched the shape of the defect: this helped to reduce the time for the surgery and contributed to good healing. One year later, newly formed and well-integrated bone was clinically available, and two implants (AnyRidge, MegaGen, Gyeongbuk, South Korea) were placed. The histologic samples retrieved from the implant sites revealed compact mature bone undergoing remodelling, marrow spaces, and newly formed trabecular bone surrounded by residual BCP particles. This study demonstrates that custom-made scaffolds can be fabricated by combining CT scans and CAD/CAM techniques. Further studies on a larger sample of patients are needed to confirm these results.

Paediatric cranial defect reconstruction using bioactive fibre-reinforced composite implant: early outcomes

BACKGROUND

In children, approximately half of cryopreserved allograft bone flaps fail due to infection and resorption. Synthetic materials offer a solution for allograft bone flap resorption. Fibre-reinforced composite with a bioactive glass particulate filling is a new synthetic material for bone reconstruction. Bioactive glass is capable of chemically bonding with bone and is osteoinductive, osteoconductive and bacteriostatic. Fibre-reinforced composite allows for fabricating thin (0.8 mm) margins for implant, which are designed as onlays on the existing bone. Bioactive glass is dissolved over time, whereas the fibre-reinforced composite serves as a biostable part of the implant, and these have been tested in preclinical and adult clinical trials. In this study, we tested the safety and other required properties of this composite material in large skull bone reconstruction with children.

METHOD

Eight cranioplasties were performed on seven patients, aged 2.5-16 years and having large (>16 cm(2)) skull bone defects. The implant used in this study was a patient-specific, glass-fibre-reinforced composite, which contained a bioactive glass particulate compound, S53P4.

RESULTS

During follow-up (average 35.1 months), one minor complication was observed and three patients needed revision surgery. Two surgical site infections were observed. After treatment of complications, a good functional and cosmetic outcome was observed in all patients. The implants had an onlay design and fitted the defect well. In clinical and imaging examinations, the implants were in the original position with no signs of implant migration, degradation or mechanical breakage.

CONCLUSIONS

Here, we found that early cranioplasty outcomes with the fibre-reinforced composite implant were promising. However, a longer follow-up time and a larger group of patients are needed to draw firmer conclusions regarding the long-term benefits of the proposed novel biomaterial and implant design. The glass-fibre-reinforced composite implant incorporated by particles of bioactive glass may offer an original, non-metallic and bioactive alternative for reconstruction of large skull bone defects in a paediatric population.

Osteointegration in Custom-made Porous Hydroxyapatite Cranial Implants: From Reconstructive Surgery to Regenerative Medicine

BACKGROUND

Custom-made porous hydroxyapatite (HA) implant (Fin-Ceramica Faenza S.p.A., Italy) is a biomimetic, osteoconductive material. Margin fusion at the bone-implant edge, cell proliferation within implant pores, and osteointegration in an animal model have already been described.

CASE DESCRIPTION

Radiological, microtomographical, and histological analyses were performed on two patients who underwent surgical explantation of cranial implants after postoperative complication. Primary devices explanted after 2 years showed areas of newly formed bone strictly osteointegrated with pores of the prosthesis. These prostheses showed a focal zone of resorption in correspondence of the newly formed bone, and no signs of inflammation or cytotoxicity were observed. A back-up prosthesis, explanted from the same patient after 6 months because of an infection, did not show presence of newly formed bone both on the surface and in the internal part of the prosthesis.

CONCLUSIONS

Custom-made porous HA implant is an osteoconductive material able to promote osteogenesis, osteointegrate with bone tissue, provide an effective cranial reconstruction, and restore functional features of the skull. However, complete bone healing is still a complex and long process.

Evolution of cranioplasty techniques in neurosurgery: historical review, pediatric considerations, and current trends

Cranial bone repair is one of the oldest neurosurgical practices. Reconstructing the natural contours of the skull has challenged the ingenuity of surgeons from antiquity to the present day. Given the continuous improvement of neurosurgical and emergency care over the past century, more patients survive such head injuries, thus necessitating more than ever before a simple, safe, and durable means of correcting skull defects. In response, numerous techniques and materials have been devised as the art of cranioplasty has progressed. Although the goals of cranioplasty remain the same, the evolution of techniques and diversity of materials used serves as testimony to the complexity of this task. This paper highlights the evolution of these materials and techniques, with a particular focus on the implications for managing pediatric calvarial repair and emerging trends within the field.

Post-marketing surveillance of CustomBone Service implanted in children under 7 years old

BACKGROUND

The CustomBone Service is a bioceramic implant suitable for cranial repair in both adults and children, although there are no clinical data about its use in children under 7 years of age. This surveillance study investigates the outcome in this age group.

METHOD

Twenty-eight children under 7 years old (range, 2.5-6 years) received CustomBone Service from July 2006 to May 2013 in 16 international hospitals. Data of 23 children (12 males and 11 females), harboring 24 prosthesis, were available with a minimum follow-up of 1 year.

FINDINGS

Sites of the cranial defect were frontal or parietal (20.8 % each), parieto-temporal (16.7 %), fronto-parietal or occipital (12.5 % each), fronto-parieto-temporal or fronto-temporal (8.3 % each). Initial diseases were trauma (54.2 %), malformation (37.5 %), or tumor of the bone/skin (8.3 %). Rupture of the implant occurred in a single case during the implant (1/26 surgeries, 3.8 %) and the cranial repair was achieved by means of the back-up prosthesis. Five adverse events were registered during the follow-up period consisting of three cases of fracture and two of exposure/infection of the prosthesis. All cases required the removal of the device (20.8 %).

CONCLUSIONS

The failure rate of CustomBone Service under 7 years of age was higher than reported in adults and children over 7 years old (20.8 vs. 3.8 %), However, CustomBone Service may be considered a valid option under 7 years old since other materials are burdened by more significant rates of complications in the long-term period. Due to specific properties of this material, indication to CustomBone Service in toddlers should be carefully evaluated by the surgeon on a case-by-case basis.

The value of three-dimensional printing modelling for surgical correction of orbital hypertelorism

Orbital hypertelorism is defined as an increased distance between both medial and lateral sides of the orbits. Most common causes are frontonasal malformations, craniofacial fissures, encephalocele and a miscellaneous group of various syndromic or chromosomal disorders. Surgical correction of orbital hypertelorism is still challenging. The present report describes a case of severe orbital hypertelorism of an 11-year-old boy, where surgical correction was planned using three-dimensional printing modelling. This approach allowed reducing time of surgery, accurately planning the location of the osteotomies and precontouring the osteosynthesis material. Three-dimensional models are very helpful tools in planning complex craniofacial operative procedures.

Interval cranioplasty with patient-specific implants and autogenous bone grafts--success and cost analysis

Different options exist for the reconstruction of craniectomy defects following interval cranioplasty. The standard procedure is still based on the re-implantation of autogenous bone specimen which can be stored in the abdominal wall or be cryopreserved. Alternatively patient-specific implants (PSIs) can be used. We conducted a retrospective study based on 50 consecutive patients with skull bone defects of 100 cm(2) or more being operated on by the same team of surgeons. Thirty-three patients agreed to take part in the study. Seventeen patients who underwent reconstruction with PSIs (titanium and polyether ether ketone, PEEK) (follow-up, 43 months [range, 3-93]) were compared with 16 control subjects who had autogenous bone grafts re-implanted (follow-up, 32 months [range, 5-92]). Criteria analyzed were the success and complication rates, operation time, duration of hospitalization and the treatment costs. Complication rate and the rate of reoperation were significantly lower, and the hospital stay was shorter in the PSI group. The treatment costs for reconstruction with autogenous bone were considerably lower than skull bone reconstruction based on PSIs (average costs: 10849.91 €/patient versus 15532.08 €/patient with PSI). Due to biological reasons some of the autogenous bone implants fail due to infection and resorption and the patients have to undergo another operation with implantation of a PSI in a secondary attempt. For those patients the highest overall treatment costs must be calculated (average costs: 26086.06 €/patient with secondary stage PSI versus 15532.08 €/patient with primary stage PSI).

CONCLUSION

High success rates and reliability of PSIs may change the treatment strategy in patients undergoing interval cranioplasty.

3D modeling, custom implants and its future perspectives in craniofacial surgery

Custom implants for the reconstruction of craniofacial defects have gained importance due to better performance over their generic counterparts. This is due to the precise adaptation to the region of implantation, reduced surgical times and better cosmesis. Application of 3D modeling in craniofacial surgery is changing the way surgeons are planning surgeries and graphic designers are designing custom implants. Advances in manufacturing processes and ushering of additive manufacturing for direct production of implants has eliminated the constraints of shape, size and internal structure and mechanical properties making it possible for the fabrication of implants that conform to the physical and mechanical requirements of the region of implantation. This article will review recent trends in 3D modeling and custom implants in craniofacial reconstruction.

Feasibility of the custom-made titanium cranioplasty CRANIOTOP(®)

Background:

With decompressive craniectomy for ischemic stroke, traumatic brain injury, and skull-infiltrating tumors, the need for cranioplasty has increased. Different materials for custom-made cranioplasties have been evaluated, but a gold standard could not yet be established. We report our experience with the new custom-made titanium CRANIOTOP^®cranioplasty (CL Instruments, Germany).

Methods:

A total of 50 consecutive patients received a CRANIOTOP cranioplasty within a 2 year interval. We reviewed the charts for time between initial surgery and cranioplasty, indication, complications, operative time, and cosmetic outcome. Postoperative imaging (computed tomography [CT] scan n = 48, magnetic resonance imaging (MRI) n = 5) was screened for fitting accuracy and for hemorrhages.

Results:

The most common indication for craniectomy were diffuse edema due to traumatic brain injury (n = 17, 34%) and ischemic stroke (n = 12, 24%). All patients were satisfied with the cosmetic result. In the postoperative CT scan accurate fitting was confirmed in all patients, the postoperative MRI was free of artifacts. Surgical revision was necessary in five patients because of empyema (n = 2), wound exposure (n = 2), and one cerebrospinal fluid fistula. Thus, the surgical morbidity was 10%.

Conclusion:

With due consideration of the limitations of this retrospective study, we feel the present data allow concluding that the custom-made titanium cranioplasty CRANIOTOP^®is safe and feasible.

Preformed titanium cranioplasty after resection of skull base meningiomas - a technical note

INTRODUCTION

Meningiomas of the fronto-basal skull are difficult to manage as the treatment usually includes extensive resection of the lesion, consecutive reconstruction of the meninges and of the skull. Especially after removal of spheno-orbital and sphenoid-wing meningiomas, the cosmetic result is of utmost importance. In this technical note, we present our institutional approach in the treatment of skull base meningiomas, focussing on the reconstruction of the neurocranium with individually preformed titanium cranioplasty (CRANIOTOP(®), CL Instruments, Germany).

CASE REPORT

Two female patients (40 years, 64 years) are presented. Both patients presented with skull base lesions suggestive of meningiomas. The preoperative thin-sliced CT scan was processed to generate a 3D-model of the skull. On it, the resection was mapped and following a simulated resection, the cranioplasty was manufactured. Intra-operatively, the titanium plate served as a template for the skull resection and was implanted after microsurgical tumour removal, consecutively. The cosmetic result was excellent. Immediate postoperative CT scan revealed accurate fitting and complete tumour removal. Control Magnetic Resonance Imaging (MRI) within 12 weeks was possible without any artifacts.

DISCUSSION

The comprehensive approach described indicates only one surgical procedure for tumour removal and for reconstruction of the skull. The titanium plate served as an exact template for complete resection of the osseous parts of the tumour. Cosmetic outcome was excellent and control MRI was possible post operatively.

CONCLUSION

CRANIOTOP(®) cranioplasty is a safe and practical tool for reconstruction of the skull after meningioma surgery.

Autologous bone flap versus hydroxyapatite prosthesis in first intention in secondary cranioplasty after decompressive craniectomy: a French medico-economical study

BACKGROUND AND PURPOSE

Decompressive craniectomy is the most common justification for cranioplasty. A medico-economial study based on the effective cost of the hydroxyapatite prosthesis, the percentage of autologous bone graft's loss due to bacterial contamination and the healthcare reimbursment, will allow us to define the best strategy in term of Healthcare economy management for the cranioplasties. A comparison was made between the two groups of patients, autologous bone flap versus custom-made prosthesis in first intention, based on the clinical experience of our department of neurosurgery.

RESULTS

No differences was shown between the two groups of patients, in terms of lenght of in-hospital stay and population's characteristics or medical codification. The mean cost of a cranioplasty using the autologous bone graft in first intention was €4045, while the use of hydroxyapatite prosthesis led to a cost of €8000 per cranioplasty.

CONCLUSION

In term of Healthcare expenses, autologous bone flap should be used in first intention for cranioplasties, unless the flap is contaminated or in specific indications, when the 3D custom-made hydroxyapatite prosthesis should be privilegied.

Shape modifications of porous hydroxyapatite prostheses to improve rigid implant fixation: Experience in 12 cases

BACKGROUND

Various methods of fixation have been described for custom made hydroxyapatite cranial implants. Their poor malleability limits most of the common used fixation techniques because of the high risk of cranioplasty's fracturing or higher exposure to infections. We present our experience with a new fixation technique, based on an appositely premodified hydroxyapatite implants.

METHODS

In a 2-year time period, 12 patients underwent cranioplasty by a modified custom made porous hydroxyapatite implant. Once the three-dimensional computer model of the prostheses was performed, three semicircular extensions placed at strategic positions were drawn and the final prosthesis was realized. At surgery, holes fitting the extensions were drilled into the skull borders and the implant was easily embedded inside the defect. Small titanium meshes overlying the extensions were fixed by screws to the surrounding bone.

RESULTS

A minimal increase of operative times was recorded, with drilling and fixation requiring additional 30 and 15 minutes, respectively. Optimal contact between cranioplasty and skull borders was always observed at control computed tomography (CT) scans. Permanent rigid fixation was obtained in all cases, with good functional and aesthetic results at follow-up.

CONCLUSIONS

Modifications of hydroxyapatite implants are obtained without additional costs. The minimal increase of operative times is largely counterbalanced by optimal fixation results. Finally, the bone drilling and the immediate proximity of bone to prosthesis might enhance the potential for osteogenesis and osteointegration.

Use of "custom made" porous hydroxyapatite implants for cranioplasty: postoperative analysis of complications in 1549 patients

Background:

Cranioplasty is a surgical intervention aimed at reestablishing the integrity of skull defects, and should be considered the conclusion of a surgical act that began with bone flap removal. Autologous bone is still considered the treatment of choice for cranioplasty. An alternative choice is bioceramic porous hydroxyapatite (HA) as it is one of the materials that meets and comes closest to the biomimetic characteristics of bone.

Methods:

The authors analyzed the clinical charts, compiled by the neurosurgeon, of all patients treated with custom-made porous HA devices (Custom Bone Service Fin-Ceramica, Faenza) from which epidemiological and pathological data as well as material-related complications were extrapolated.

Results:

From November 1997 to December 2010, 1549 patients underwent cranioplasty with the implantation of 1608 custom-made porous HA devices. HA was used in 53.8% of patients for decompressive craniectomy after trauma or intracranial hemorrhage, while the remaining cases were for treated for comminuted fracture, cutaneous or osseous resection, cranial malformation, autologous bone reabsorption or infection or rejection of previously implanted material. The incidence of adverse events in patients treated for cranioplasty, as first line treatment was 4.78% (56 events/1171 patients), and 5.02%, (19 events/378 patients) at second line.

Conclusion:

This study demonstrates that HA is a safe and effective material, is well tolerated in both adult and pediatric patients, and meets the requirements necessary to repair craniolacunia.

A new custom made bioceramic implant for the repair of large and complex craniofacial bone defects

INTRODUCTION

Neurosurgery and Maxillofacial Surgery Departments of Limoges University Hospital Centre have developed a new concept of a custom made ceramic implant in hydroxyapatite (HA) for the reconstruction of large and complex craniofacial bone defects (more than 25 cm(2)).

MATERIALS AND METHODS

The manufacturing process of the implants used a stereolithography technique that produces implants with three-dimensional shapes derived directly from the scan file of the patient's skull without moulding or machining. Eight patients received 8 implants between 2005 and 2008.

RESULTS

The surgical procedure is simple and fast. The post-operative follow-up was 12 months. No major complications (infection or fracture of the implant) were observed. The cosmetic result was considered satisfactory by both patients and surgeons.

CONCLUSIONS

These new implants are well suited for reconstruction of large craniofacial bone defects (greater than 25 cm(2)) in adults and children over 8 years.

A review of reconstructive materials for use in craniofacial surgery bone fixation materials, bone substitutes, and distractors

Over the last 40 years, craniofacial surgery, in general, and surgery for craniosynostosis, in particular, has witnessed the introduction of a number of new materials for use in operations involving the cranial vault. Some of these materials have proven quite useful over time, while others have failed to meet their stated objectives. In this review, the more popular implant materials are analyzed, and their relative merits and drawbacks are discussed. Craniofacial surgery in the pediatric population has its own unique limitations, quite different from the adult population and those issues are reviewed as well.