Titanium mesh and hydroxyapatite cement cranioplasty: a report of 20 cases

Role of Plastic Surgery in the Treatment of Titanium Mesh Exposure Following Cranioplasty

BACKGROUND

Titanium mesh cranioplasty is the most common strategy for the repair of skull defects. However, as the frequency of cranioplasty increases, the incidence of titanium mesh exposure following cranioplasty increases as well. This study aimed to investigate the methods and outcomes of plastic surgery in the management of titanium mesh exposure following cranioplasty.

METHODS

Patients with titanium mesh exposure following cranioplasty were retrospectively selected from January 2016 to August 2021. Titanium mesh exposure was corrected with reconstructive plastic surgery, including skin grafting, expander insertion, partial removal of the exposed mesh, replacement of the mesh, or flap transplantation.

RESULTS

This study included 21 patients with titanium mesh exposure with surgical site infection and a variant of scalp deformity. The age of the patients ranged from 18 to 74 years, with the mean age being 54 years. All patients underwent reconstructive plastic surgery and exhibited complete wound healing. The follow-up period ranged from 17 to 90 months. One patient experienced titanium mesh re-exposure and subsequently underwent an additional procedure for the partial removal of the exposed mesh. No serious complications were observed postoperatively.

CONCLUSION

Reconstructive plastic surgery can facilitate wound healing at the titanium mesh exposure site following cranioplasty. However, an individualized treatment strategy is required for each patient, and complications should be managed by adopting standard measures.

Utilization of carbonated calcium phosphate cement for contouring cranioplasty in patients with syndromic craniosynostosis

PURPOSE

Carbonated calcium phosphate (CCP) cement is an alloplastic material which has been increasingly utilized for cranioplasty reconstruction; however, there is a paucity of data investigating its use in patients with syndromic craniosynostosis. The purpose of this study was to characterize our institutional experience with CCP cement for secondary contouring cranioplasty in these patients to establish safety and aesthetic efficacy.

METHODS

Patients with syndromic craniosynostosis undergoing cranioplasty with CCP cement from 2009 to 2022 were retrospectively reviewed for prior medical and surgical history, cranioplasty size, cement usage, and postoperative complications. Aesthetic ratings of the forehead region were quantified using the Whitaker scoring system at three timepoints: preoperative (T1), < 6 months postoperative (T2), and > 1 year postoperative (T3).

RESULTS

Twenty-one patients were included. Age at surgery was 16.2 ± 2.8 years, forehead cranioplasty area was 135 ± 112 cm², and mass of cement was 17.2 ± 7.8 g. Patients were followed for 3.0 ± 3.1 years. Whitaker scores decreased from 1.9 ± 0.4 at T1 to 1.4 ± 0.5 at T2 (p = 0.005). Whitaker scores at T2 and T3 were not significantly different (p = 0.720). Two infectious complications (9.5%) were noted, one at 4.5 months postoperatively and the other at 23 months, both requiring operative removal of CCP cement.

CONCLUSION

Our results suggest that aesthetic forehead ratings improve after CCP contouring cranioplasty and that the improvement is sustained in medium-term follow-up. Complications were uncommon, suggesting that CCP is relatively safe though longer-term follow-up is needed before reaching definitive conclusions.

Complications of Different Types of Cranioplasty and Identification of Risk Factors Associated with Cranioplasty at a Tertiary Care Centre: A Prospective Observational Study

Objective Decompressive craniectomy (DC) is an urgent procedure which is done to decrease intracranial pressure. A study of the complications would suggest measures to improve the care. This study was focused on analyzing the complications after cranioplasty (CP) and to identify risk factors that may be associated with the failure of the procedure.

Method: This study was conducted over 41 months at level-1 trauma center and medical college. It included patients undergoing CP for a defect arising out of previous DC or inability to replace the bone flap (Glasgow Coma Scale > 13, size > 5 cm, without surgical site infection). All patients underwent CT imaging before and after the procedure. The CP technique largely depended on the patients, based on the cost of prosthesis and availability.

Result: Hundred patients were included in the study. Postoperatively, total 22 patients suffered complications of which few had more than one complication. Titanium implant appeared to be a better implant, with no complication (p < 0.05). Complication was common in younger age group, chemically cured PMMA (polymethyl methacrylate) and ethylene oxide) sterilized bone flap). Complications were higher among patients with multiple comorbidity and stroke patients.

Conclusion: Titanium flap had no complication and in case of autologous abdominal subcutaneous flap, apart from bone flap absorption, patients had no major complication. Therefore, both implants are preferred implants for CP. Heat-cured PMMA can be used in case of nonavailability of a better option, as it is economical feasible and can be molded at any dental lab.

Drainage and Orbitofrontal Reconstruction After Removal of a Giant Frontal Sinus Osteoma: A Case Report

After removal of a large frontal sinus osteoma in this case, the contralateral nasofrontal canal was opened to drain the intraoperative fluid and prevent infection, and the defect in the orbitofrontal area was restored using a titanium mesh designed with 3D printing technology.

Evaluation of the Fitting Accuracy of CAD/CAM-Manufactured Patient-Specific Implants for the Reconstruction of Cranial Defects-A Retrospective Study

Cranioplasties show overall high complication rates of up to 45.3%. Risk factors potentially associated with the occurrence of postoperative complications are frequently discussed in existing research. The present study examines the positioning of 39 patient-specific implants (PSI) made from polyetheretherketone (PEEK) and retrospectively investigates the relationship between the fitting accuracy and incidence of postoperative complications. To analyze the fitting accuracy of the implants pre- and post-operatively, STL files were created and superimposed in a 3D coordinate system, and the deviations were graphically displayed and evaluated along with the postoperative complications. On average, 95.17% (SD = 9.42) of the measurements between planned and surgically achieved implant position were within the defined tolerance range. In cases with lower accordance, an increased occurrence of complications could not be demonstrated. The overall postoperative complication rate was 64.1%. The fitting of the PEEK-PSI was highly satisfactory. There were predominantly minor deviations of the achieved compared to the planned implant positions; however, estimations were within the defined tolerance range. Despite the overall high accuracy of fitting, a considerable complication rate was found. To optimize the surgical outcome, the focus should instead be directed towards the investigation of other risk factors.

Bone Cement Cranioplasty Reduces Cerebrospinal Fluid Leak Rate after Microvascular Decompression: A Single-Institutional Experience

Background  Microvascular decompression (MVD) is a common surgical treatment for cranial nerve compression, though cerebrospinal fluid (CSF) leak is a known complication of this procedure. Bone cement cranioplasty may reduce rates of CSF leak. Objective  To compare rates of CSF leak before and after implementation of bone cement cranioplasty for the reconstruction of cranial defects after MVD. Methods  Retrospective chart review was performed of patients who underwent MVD through retrosigmoid craniectomy for cranial nerve compression at a single institution from 1998 to 2017. Study variables included patient demographics, medical history, type of closure, and postoperative complications such as CSF leak, meningitis, lumbar drain placement, and ventriculoperitoneal shunt insertion. Cement and noncement closure groups were compared, and predictors of CSF leak were assessed using a multivariate logistic regression model. Results  A total of 547 patients treated by 10 neurosurgeons were followed up for more than 20 years, of whom 288 (52.7%) received cement cranioplasty and 259 (47.3%) did not. Baseline comorbidities were not significantly different between groups. CSF leak rate was significantly lower in the cement group than in the noncement group (4.5 vs. 14.3%; p  < 0.001). This was associated with significantly fewer patients developing postoperative meningitis (0.7 vs. 5.2%; p  = 0.003). Multiple logistic regression model demonstrated noncement closure as the only independent predictor of CSF leak (odds ratio: 3.55; 95% CI: 1.78-7.06; p  < 0.001). Conclusion  CSF leak is a well-known complication after MVD. Bone cement cranioplasty significantly reduces the incidence of postoperative CSF leak and other complications. Modifiable risk factors such as body mass index were not associated with the development of CSF leak.

Contemporary Review on Craniectomy and Cranioplasty; Part 2: Material Selection and Plate Manufacture

ABSTRACT

Cranioplasty materials include metals (ie, titanium); ceramics (ie, hydroxyapatite); polymers (ie, poly-methyl-metha-acrylate [PMMA]); and plastics (ie, polyether ether ketone). This paper aims to review their advantages and drawbacks. No ideal material currently exist, however, titanium implants are universally agreed to have lower infection rates than those reported for hydroxyapatite and PMMA implants; thus justifying their current wide use. These implants can be manufactured conventionally from medical grade titanium alloy Ti64 (titanium-aluminum-vanadium) in the form of plates ranging in thickness from 0.5 to 0.7 mm thick, or following the computer-aided design/manufacture principle. Surface finish of these implants is best achieved by electroplating.

Evaluation of Patient-Specific Cranial Implant Design Using Finite Element Analysis

BACKGROUND

Various studies have investigated the load-bearing capacity of patient-specific cranial implants. However, little attention has been given to the evaluation of the design of ceramic-titanium (CeTi) implants.

METHODS

A biomechanical evaluation of 3 patient-specific cranial implants was performed using finite element analysis.

RESULTS

The results of the analyses allowed the identification of the implant regions as well as the magnitudes of the maximum stresses on, and displacements along, these regions after traumatic impact. The analyses also showed that polyether ether ketone cranial implants offer inferior brain and neurocranial protection due to their high flexibility and local peak stresses at the bone-screw interface. In contrast, CeTi implants were able to evenly distribute the stresses along the interface and thus reduced the risk of neurocranial fracture. The scaffold structure at the border of these implants reduced stress shielding and enhanced bone ingrowth. Moreover, brain injuries were less likely to occur, as the CeTi implant exhibits limited deflection.

CONCLUSIONS

From the finite element analyses, CeTi cranial implants appear less likely to induce calvarial fractures with a better potential to protect the brain under impact loads.

Spontaneous Bone Flap Resorption Following Cranioplasty Using Autologous Bone

ABSTRACT

Cranioplasty is a common neurosurgical procedure. The main reasons for performing cranioplasty are, in addition to aesthetic correction and protection of the brain, the reestablishment of the adequate flow of cerebrospinal fluid and the prevention of complications inherent to the perpetuation of bone failure. In our institution the patient's autologous bone remains the best method for performing cranioplasty, despite the existence of other heterologous grafts and bone substitutes. Despite representing for us, the best material for cranioplasty, the use of autologous grafting is subject to complications. In this paper, the authors present the case of a patient who underwent cranioplasty with autologous bone that progressed with spontaneous resorption of the bone flap. The authors herein briefly discuss the case and review the literature on the subject, with an emphasis on the factors that can lead to such an outcome.

Exchange Cranioplasty Using Bioabsorbable Hydroxyapatite and Collagen Complex After Removal of an Extensive Frontal Bone Tumor in an Infant

BACKGROUND

Forehead reconstruction is challenging. Reconstruction of the innate curvature of the forehead is difficult, and the forehead is an esthetically important part of the face. Although synthetic implants and autologous split bone grafts are useful, these cannot be used in infants.

CASE DESCRIPTION

A 4-month-old girl was presented with a right frontal bone Ewing sarcoma. The tumor was removed, and the defect was reconstructed with an autologous contralateral parietal bone graft. The parietal bone defect was repaired with a bioabsorbable hydroxyapatite and collagen complex. Good reconstruction of the forehead and ossification of the donor site was achieved within 3 years after surgery.

CONCLUSIONS

After removal of an extensive frontal bone tumor in an infant, exchange cranioplasty with an autograft using a bioabsorbable hydroxyapatite and collagen complex at the donor site yielded good results.

Cranioplasty after craniectomy in pediatric patients-a systematic review

INTRODUCTION

Complications following cranioplasty with either autografts or cranial implants are commonly reported in pediatric patients. However, data regarding cranioplasty strategies, complications and long-term outcomes are not well described. This study systematically reviews the literature for an overview of current cranioplasty practice in children.

METHODS

A systematic review of articles published from inception to July 2018 was performed. Studies were included if they reported the specific use of cranioplasty materials following craniectomy in patients younger than 18 years of age, and had a minimum follow-up of at least 1 year.

RESULTS

Twenty-four manuscripts, describing a total of 864 cranioplasty procedures, met the inclusion criteria. The age of patients in this aggregate ranged from 1 month to 20 years and the weighted average was 8.0 years. The follow-up ranged from 0.4 months to 18 years and had a weighted average of 40.4 months. Autologous bone grafts were used in 484 cases (56.0%). Resorption, infection and/or hydrocephalus were the most frequently mentioned complications. In this aggregate group, 61 patients needed a revision cranioplasty. However, in 6/13 (46%) papers studying autologous cranioplasties, no data was provided on resorption, infection and revision cranioplasty rates. Cranial implants were used in 380 cases (44.0%), with custom-made porous hydroxyapatite being the most commonly used material (100/380, 26.3%). Infection and migration/fracturing/loosening were the most frequently documented complications. Eleven revision cranioplasties were reported. Again, no data was reported on infection and revision cranioplasty rates, in 7/16 (44%) and 9/16 (56%) of papers, respectively.

CONCLUSION

Our systematic review illuminates that whether autografts or cranial implants are used, postcranioplasty complications are quite common. Beyond this, the existing literature does not contain well documented and comparable outcome parameters, suggesting that prospective, long-term multicenter cohort studies are needed to be able to optimize cranioplasty strategies in children who will undergo cranioplasty following craniectomy.

Cranioplasties following craniectomies in children-a multicenter, retrospective cohort study

OBJECTIVE

Complications following pediatric cranioplasty after craniectomy with either autologous bone flaps or cranial implants are reported to be common, particularly bone flap resorption. However, only sparse data are available regarding cranioplasty strategies, complications, and outcomes. This manuscript describes a Canadian-Dutch multicenter pediatric cohort study with autografts and cranial implant cranioplasties following craniectomies for a variety of indications.

METHODS

The study included all children (< 18 years) who underwent craniectomy and subsequent cranioplasty surgeries from 2008 to 2014 (with a minimum of 1-year follow-up) at four academic hospitals with a dedicated pediatric neurosurgical service. Data were collected regarding initial diagnosis, age, time interval between craniectomy and cranioplasty, bone flap storage method, type of cranioplasty for initial procedure (and redo if applicable), and the postoperative outcome including surgical site infection, wound breakdowns, bone flap resorption, and inadequate fit/disfigurement.

RESULTS

Sixty-four patients (46 males, average age 9.7 ± 5.5 years) were eligible for inclusion, with mean follow-up of 82.3 ± 31.2 months after craniectomy. Forty cranioplasties (62.5%) used autologous bone re-implant, 23 (57.5%) of which showed resorption. On average, resorption was documented at 434 days (range 62-2796 days) after reimplantation. In 20 cases, a revision cranioplasty was needed. In 24 of the post-craniectomy cases (37.5%), a cranial implant was used with one of ten different implant types. Implant loosening prompted a complete revision cranioplasty in 2 cases (8.3%). Cranial implants were associated with low morbidity and lower reoperation dates compared to the autologous cranioplasties.

CONCLUSION

The most prominent finding in this multicenter cohort study was that bone flap resorption in children remains a common and widespread problem following craniectomy. Cranioplasty strategies varied between centers and evolved over time within centers. Cranial implants were associated with low morbidity and low reoperation rates. Still, longer term and prospective multicenter cohort studies are needed to optimize cranioplasty strategies in children after craniectomies.

Hydroxyapatite cement cranioplasty for translabyrinthine surgery: A single institution experience

OBJECTIVE

To assess complication rates in hydroxyapatite cement (HAC) cranioplasty for translabyrinthine acoustic surgery compared with historical controls.

METHODS

Retrospective chart review of patients undergoing de novo translabyrinthine surgery with HAC cranioplasty without concurrent adipose tissue graft or additional material between 2010 and 2017 at a tertiary otology center.

RESULTS

Fifty-two patients underwent HAC cranioplasty during the study period. The average length of follow-up was 30.5 months. HAC cranioplasty was associated with acceptable rates of cerebrospinal fluid leak (3.8%), wound or intracranial infection (5.8%), need for unplanned revision surgery (9.6%), and all complications (15.3%). All complications occurred within 5 months of surgery. No delayed wound infections or implant extrusions occurred.

CONCLUSION

HAC cranioplasty has an acceptable complication profile for translabyrinthine surgery and is a viable alternative to abdominal fat grafting without associated donor site morbidity.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:206-211, 2020.

Assessment of Bioabsorbable Hydroxyapatite for Cranial Defect in Children

PURPOSE

To evaluate the utility and efficacy of bioabsorbable hydroxyapatite and collagen complex (HA/Col) for cranioplasty repair of cranial bone defects in children.

METHODS

Two patients (a 6-year-old male and 11-year-old female) with Treacher Collins syndrome received zygoma and orbital floor reconstruction using a full thickness of parietal bone. The bone grafts were taken from each patient's parietal cranium. The right parietal cranial defect was repaired with autologous bone dust, and the left side was repaired with HA/Col in each patient. Computed tomography scans were taken immediately after and at 12 months following surgery. The osteosynthesis areas and thicknesses were measured using computer-aided engineering.

RESULTS

Both patients experienced no complications, including infection. In the 6- and 11-year-old patients, the extent of osteosynthesis for HA/Col was 92.2% and 89.4%, respectively; and for the autologous bone dust was 78.5% and 53.2%, respectively. Because of the small sample size, a significant difference could not be calculated; however, the percentage of osteosynthesis for HA/Col was higher than for the autologous bone dust.

CONCLUSION

This study showed that HA/Col can be effectively used in cranial defects and can be considered an alternative graft material for cranial reconstruction.

Treatment of calvarial defects by resorbable and non-resorbable sonic activated polymer pins and mouldable titanium mesh in two dogs: a case report

BACKGROUND

To date, calvarial defects in dogs have traditionally been addressed with different types of implants including bone allograft, polymethylmethacrylate and titanium mesh secured with conventional metallic fixation methods. This report describes the use of an absorbable and non absorbable novel polymer fixation method, Bonewelding® technology, in combination with titanium mesh for the repair of calvarial defects in two dogs. The clinical outcomes and comparative complication using resorbable and non-resorbable thermoplastic pins were compared.

CASE PRESENTATION

This report of two cases documents the repair of a traumatic calvarial fracture in an adult male Greyhound and a cranioplasty following frontal bone tumor resection in an adult female Cavalier King Charles Spaniel with the use of a commercially available titanium mesh secured with an innovative thermoplastic polymer screw system (Bonewelding®). The treatment combination aimed to restore cranial structure, sinus integrity and cosmetic appearance. A mouldable titanium mesh was cut to fit the bone defect of the frontal bone and secured with either resorbable or non-resorbable polymer pins using Bonewelding® technology. Gentamycin-impregnated collagen sponge was used intraoperatively to assist with sealing of the frontal sinuses. Calvarial fracture and post-operative implant positioning were advised using computed tomography. A satisfactory restoration of skull integrity and cosmetic result was achieved, and long term clinical outcome was deemed clinically adequate with good patient quality of life. Postoperative complications including rostral mesh uplift with minor associated clinical signs were encountered when resorbable pins were used. No postoperative complications were experienced in non-resorbable pins at 7 months follow-up, by contrast mesh uplift was noted 3 weeks post-procedure in the case treated using absorbable pins.

CONCLUSIONS

The report demonstrates the innovative use of sonic-activated polymer pins (Bonewelding® technology) alongside titanium mesh is a suitable alternative technique for skull defect repair in dogs. The use of Bonewelding® may offer advantages in reduction of surgical time. Further, ultrasonic pin application may be less invasive than alternative metallic fixation and potentially reduces bone trauma. Polymer systems may offer enhanced mesh-bone integration when compared to traditional metallic implants. The use of polymer pins demonstrates initial potential as a fixation method in cranioplasty. Initial findings in a single case comparison indicate a possible advantage in the use of non-absorbable over the absorbable systems to circumvent complications associated with variable polymer degradation, further long term studies with higher patient numbers are required before reliable conclusions can be made.

Forehead reconstruction with a custom-made three-dimensional titanium implant in a Parry-Romberg syndrome patient

Parry-Romberg syndrome is a rare neurocutaneous syndrome characterized by progressive shrinkage and degeneration of the tissues usually on only one side of the face. It is usually difficult to restore the facial contour due to skin tightness. In this case report, we report a forehead reconstruction with custom-made three-dimensional (3D) titanium implant of a Parry-Romberg syndrome patient who was treated with multiple fat grafts but had limited effect. A 36-year-old man presented with hemifacial atrophy. The disease progressed from 5 to 16 years old. The patient had alopecia on frontal scalp and received a surgery using tissue expander. The alopecia lesion was covered by expanded scalp flap done 22 years ago. Also, he was treated with fat grafts on depressed forehead 17 years ago. However, it did not work sufficiently, and there was noted depressed forehead. We planned to make 3D titanium implant to cover the depressed area (from the superior orbital rim to the vertex). During the operation, we confirmed that the custom-made 3D implant accurately fit for the depressed area without any dead spaces. Previously depressed forehead and glabella were elevated, and the forehead contour was improved cosmetically. A custom-made 3D titanium implant is widely used for skull reconstruction and bring good results. In our case, the depressed forehead of a Parry-Romberg syndrome patient was improved by a 3D titanium implant.

Classification of the Residual Cranial Defects and Selection of Reconstruction Materials

The cranial defects are complex in nature and are due to various causes. Therefore, there is a need for a common term of reference to these defects. This requirement stood as a prime reason for proposing a classification system for cranial defects. The classification is based on 2 decades of experience in cranioplasty. This efficient and simple way of representation would fill the existing lacunae for a systematic communication on cranial defects. Over the ages the evolution of reconstruction and grafting had undergone a massive progress. Therefore, it is essential to enumerate all available graft and bio-materials for restoring the cranial defects. The aetiology for these defects, age and sex of the patient, site and size of the defect, associated systemic conditions, cost factor, and operator's choice are the factors that play key role in the selection of the reconstructive material. This article discusses on these factors in cranioplasty. High success rate with excellent function and cosmetic outcome in using a variety of materials, as shared in this article. The advantages of autografts cannot be matched by any existing alloplast. However, in case of larger defects, for a better cosmetic outcome and to reduce the donor site morbidity, alloplasts are the most widely preferred material of choice.

Hydroxyapatite bone cement for suboccipital retrosigmoid cranioplasty: A single institution case series

OBJECTIVE

To report rates of cerebrospinal fluid leak, wound infection, and other complications after repair of retrosigmoid craniotomy with hydroxyapatite bone cement.

METHODS

Retrospective case review at tertiary referral center of patients who underwent retrosigmoid craniotomy from 2013 to 2016 with hydroxyapatite cement cranioplasty.

OUTCOME MEASURES

Presence of absence of cerebrospinal fluid leak, wound infection, and other complications.

RESULTS

Twenty cases of retrosigmoid craniotomy repaired with hydroxyapatite cement were identified. Median length of follow up was 9.8months. No cases of cerebrospinal fluid leak were identified. One patient developed a wound infection which was thought to be related to a chronic inflammatory response to the implanted dural substitute. No other major complications were noted.

CONCLUSIONS

A method and case series of suboccipital retrosigmoid cranioplasty using hydroxyapatite cement and a are reported. Hydroxyapatite cement cranioplasty is a safe and effective technique for repair of retrosigmoid craniotomy defects.

Hydroxyapatite bone cement application for the reconstruction of retrosigmoid craniectomy in the treatment of cranial nerves disorders

BACKGROUND

Retromastoid craniectomy (RSC) is a cardinal surgical approach used to access the posterior fossa. Hydroxyapetite bone cement (HBC) is frequently employed for cranioplasty in efforts to prevent cerebrospinal fluid (CSF) leak, whilst maintaining low complication rates and good cosmetic satisfaction. The authors aim to determine the safety and effectiveness of HBC for reconstruction RSC used for treatment of various cranial nerves disorders.

METHODS

The authors conducted a retrospective one-center two surgeons review of 113 patients who underwent RSC filled with HBC for the treatment of cranial nerve disorders. The study period extended from January 2011 through April 2016. Charts were reviewed for documentation of descriptors pertinent to the endpoints described above. Revisions and reoperations were excluded from analysis.

RESULTS

Ninety-three patients met the inclusion criteria; there was one case of postoperative pseudomeningocele, which was considered as CSF leak (1%), 3 (3,2%) superficial infections, and no deep infections. Cosmetic satisfaction was obtained in all but one case (98.9% satisfaction) and long-term incisional pain was problematic in 1 (1.1%) patient. Other complications (serous drainage, headache, ear pain) accounted for three cases (3.2%).

CONCLUSIONS

The application of HBC in the reconstruction of RSC for the treatment of cranial nerves disorders is an effective method, yielding good cosmetic results whilst eliminating CSF leak. Additionally, it is safe due to the lack of deep-seated wound infections with low incidence of chronic incisional pain.

Autogenous Bone Reconstruction of Large Secondary Skull Defects

BACKGROUND

The authors sought to ascertain the upper limits of secondary skull defect size amenable to autogenous reconstructions and to examine outcomes of a surgical series. Published data for autogenous and alloplastic skull reconstructions were also examined to explore associations that might guide treatment.

METHODS

A retrospective review of autogenously reconstructed secondary skull defects was undertaken. A structured literature review was also performed to assess potential differences in reported outcomes between autogenous bone and synthetic alloplastic skull reconstructions. Weighted risks were calculated for statistical testing.

RESULTS

Ninety-six patients underwent autogenous skull reconstruction for an average defect size of 93 cm (range, 4 to 506 cm) at a mean age of 12.9 years. The mean operative time was 3.4 hours, 2 percent required allogeneic blood transfusions, and the average length of stay was less than 3 days. The mean length of follow-up was 28 months. There were no postoperative infections requiring surgery, but one patient underwent secondary grafting for partial bone resorption. An analysis of 34 studies revealed that complications, infections, and reoperations were more commonly reported with alloplastic than with autogenous reconstructions (relative risk, 1.57, 4.8, and 1.48, respectively).

CONCLUSIONS

Autogenous reconstructions are feasible, with minimal associated morbidity, for patients with skull defect sizes as large as 500 cm. A structured literature review suggests that autogenous bone reconstructions are associated with lower reported infection, complication, and reoperation rates compared with synthetic alloplasts. Based on these findings, surgeons might consider using autogenous reconstructions even for larger skull defects.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

An Outcomes Comparison Between Autologous and Alloplastic Cranioplasty in the Pediatric Population

BACKGROUND

The use of alloplastic material in cranial reconstruction has been well described in the adult population, especially when a paucity of autologous tissue exists. In children it is unknown how long-term growth, however, may be affected by the implantation of nonexpansible alloplastic material. Therefore, the authors sought to compare the outcomes of pediatric patients undergoing alloplastic versus autologous cranial reconstruction.

METHODS

To assess the safety and long-term outcomes of alloplastic cranioplasty in children, an institutional review board-approved, retrospective, single institution review of pediatric patients undergoing cranioplasty was performed from 2000 to 2014. The age at surgery, cause of the cranial defect, defect size, time since initial surgery to reconstruction, implant type, and complications were assessed. Postreconstruction imaging was reviewed if available.

RESULTS

A reconstructive cranioplasty was performed in 41 pediatric patients (ages 1-19 years, average 7.35 years). Thirty patients underwent alloplastic reconstruction (age 4.37 ± 5.57 years), and 11 underwent autologous reconstruction (age 2.00 ± 3.74 years). The size of the cranial defects was 144.01 ± 393.04 cm for autologous and 405.31 ± 572.96 cm for alloplastic reconstructions. Follow-up for all patients was an average of 2.33 ± 2.76 years (0.1-9 years). No patients in either group showed evidence of elevated intracranial pressure after cranioplasty. In long-term follow-up, none of the implants were exposed or lost because of infection. Computed tomography and physical examination demonstrated that there was no skull growth restriction in either group.

CONCLUSIONS

Our data show that alloplastic cranioplasty in the pediatric population is a safe alternative, when autologous cranial bone is not available.

Cranial Reconstruction Using Autologous Bone and Methylmethacrilate

BACKGROUND

Having in mind the importance of reconstruction of the calvaria, our goal was to compare the complication rates following the use of autologous bone and methylmethacrilate grafts, and explain the factors influencing them.

METHODS

The authors collected information of all the patients undergoing cranial reconstructive surgery (N = 149) at the Military Medical Academy in Belgrade. Procedures were performed either using a craniotomy bone flap, removed and replaced in the same act, or using methylmethacrilate. These 2 groups were compared using the Chi-squared test, controlling for the confounding influence of the size of the defect.

RESULTS

Intracranial neoplasms were the cause for the reconstruction in 71.1% of patients. The total complication rate was 7.4%, while the infection rate was 5.4%. The infection rate was significantly higher in those procedures done using methylmethacrilate (11.3% compared with 2.1%, P = 0.017), but when controlling for the confounding effect of the size of the defect treated, the difference in infection rate was significant only in large defects (13.9% compared with 2%, P = 0.031), while for small defects the difference was not statistically significant.

CONCLUSIONS

Our study suggests that the material used for reconstruction of calvaria influences the infection rate only in large and complicated defects. Considering the importance of the reconstruction, further studies should explore and confirm the role of material type on the rate of complications.

Influence of backscatter radiation on cranial reconstruction implants

OBJECTIVE

We aimed to evaluate backscatter dose variations in different cranial bone implant materials in an experimental model designed to simulate post-operative radiotherapy.

METHODS

We assessed the radiation backscatter doses associated with sheet- and mesh-type titanium plates and hydroxyapatite (HAP) samples (porosity: 35%, 50% and 85%). The samples were irradiated with 6- and 10-MV photon beams from a linear accelerator. Measurements were obtained using an ionization chamber and radiochromic films cut from the same batch.

RESULTS

At 6 MV, the titanium sheet showed the highest peak for backscattered radiation, followed by (in decreasing order) HAP30%, HAP50%, titanium mesh and HAP85%. At 10 MV, HAP30% showed the highest peak, followed by HAP50%, titanium sheet, titanium mesh and HAP85%. The peaks were at different depths in the titanium and HAP samples. The thickness of the human scalp is approximately 7 mm; therefore, measurements were obtained 0-7 mm above the implants to assess the likely dose on the scalp. A comparison of the maximum dose on the scalp showed the titanium sheet had the highest dose at both 6 and 10 MV.

CONCLUSION

The backscatter dose differed with the density of the material and the backscatter depth was different for each material. Advances in knowledge: Ulcer formation due to radiotherapy after brain tumour depends on not only radiation but also the implant material. Therefore, the density and type of implant material should be considered when planning radiotherapy and selecting bone reconstruction materials.

Fronto-orbital reconstruction using polymethyl methacrylate implant

The objective of this article is to show a case of fronto-orbital reconstruction with prefabricated polymethyl methacrylate prosthesis. A 35-year-old male with alleged history of trauma following road traffic accident 3 months back reported with unaesthetic scar and deformity in right supraorbital region to us. As there was no functional deformity, the management was aimed at correcting the contour and esthetic only. The correction was achieved by overlaying the defect with a polymethyl methacrylate implant fabricated over a three-dimensional stereolithographically printed rapidly prototyped model. Postoperative phase was uneventful and esthetic outcome was satisfactory. The patient after 4-year follow-up reported with no discomfort and definite improvement in facial contour.

Multidisciplinary approach for reconstruction of cranial defect with polymethyl methacrylate resin reinforced with titanium mesh

Cranial defects occur most commonly as a sequelae to trauma, the incidence being as high as 70%. The successful management of a case of trauma in an emergency situation requires quick evacuation of the hematoma, repair of the dura, and the scalp but not necessarily the integrity of the calvarial segment as an immediate measure. So the reconstruction of the calvarial defect in these cases is mostly carried out as a secondary procedure. Various materials are used for reconstruction of cranial defects, polymethyl methacrylate (PMMA) resin being one of them. In this article, we report a case which was successfully treated by PMMA resin in combination with a titanium mesh for reconstruction of the cranial defect as a secondary procedure.

Hydroxyapatite Cement in Craniofacial Reconstruction

OBJECTIVES: To evaluate the long-term efficacy of hydroxyapatite cement in craniofacial reconstruction, specifically examining the role (if any) of radiation, implant location, and cement type.

STUDY DESIGN: A retrospective chart review was conducted of all patients presenting to the senior surgeon (Y.D.) for craniofacial reconstruction from September 1997 to April 2004.

METHODS: Data were collected including type of cement used, size of defect, complications, need for removal of cement, reason for defect, and pathologic results of examination of removed cements.

RESULTS: One hundred two patients were identified who underwent craniofacial reconstruction with hydroxyapatite cements, 7 of whom required complete implant removal (6 Norian and 1 Mimix), and 4 (2 Norian and 2 Bone source) of whom required partial implant removal for foreign body reaction. Five of the removals were in patients who underwent postoperative radiation.

CONCLUSIONS: Hydroxyapatite cements are safe in craniofacial reconstruction. The highest risk of implant infection comes from reconstruction in the area of the frontal sinus, immediately beneath coronal incisions, and in patients who receive postoperative radiation treatment. Based on our results, there does appear to be a statistically significant difference in rates of infection and foreign body reaction between the different types of hydroxyapatite cement. We would not recommend implantation of this material in contact with the frontal sinus. Caution should be exercised when it is placed directly beneath an incision or in patients receiving postoperative radiation, particularly if a boost dose is given.

EBM RATING: C

Materials and techniques used in cranioplasty fixation: A review

Cranioplasty is the surgical repair of a deficiency or deformity of the skull. The purpose of cranioplasty is to provide protection for the brain following cranial surgery, and to offer relief to psychological disadvantages while increasing social performance. There are several materials that had been used for cranioplasty but an ideal product has yet to be developed, hence the ongoing research into biologic and non-biologic alternatives to the existing materials. This article critiques the products currently used for cranioplasty in order to facilitate the development of new materials, which can improve patient outcomes.

A new approach to aesthetic maxillofacial surgery: surgical treatment of unilateral exophthalmos due to maxillary sinus mucocele

Maxillary sinus mucocele, known as a rare condition, can cause major therapeutic difficulties, especially when it invades the orbit leading to exophthalmia. Treatment is very difficult because the eye globe has to be repositioned, and the facial symmetry needs to be reconstructed as a result of malar bone invasion. This article reports the case of a 54-year-old patient with unilateral exophthalmia caused by the evolution of a maxillary mucocele that extended toward the orbit after destroying the malar bone and the orbital floor. The treatment consisted of a 1-step restoration of both the orbit floor and the malar bone using a temporomandibular flap composed of 2 bone fragments. Lipostructure and a titanium mesh to reconstruct the calvarial defect were necessary to restore facial aesthetics after placing back the eye globe in its initial site. After surgery, the patient followed a complex rehabilitation program including massage kinesiotherapy and psychological consultation and support. These had an essential contribution to the successful final outcome in terms of psychological impact, functionality, and aesthetics.

Biodegradable Mineralized Collagen Plug for the Reconstruction of Craniotomy Burr-Holes: A Report of Three Cases

Objectives

In this case report, we describe the design, fabrication and clinical outcomes of a novel bioresorbable, mineralized collagen burr-hole plug for the reconstruction of craniotomy burr-holes.

Methods

Mineralized collagen burr-hole plugs were fabricated via a biomimetic mineralization process. The biomimetic mineralized collagen has a similar chemical composition and microstructure to natural bone tissue, thereby possessing good biocompatibility and osteoconductivity. The mineralized collagen burr-hole plugs were implanted into three patients, and clinical outcomes were evaluated at one-year follow-ups.

Results

All bone defects healed very well using the mineralized collagen burr-hole plugs, and there were no adverse reactions at the surgical sites.

Conclusions

The clinical outcomes indicated that the mineralized collagen was effective for reconstructing burr-holes in the skull after craniotomy.

A technique for intraoperative creation of patient-specific titanium mesh implants

Prefabricated, patient-specific alloplastic implants for cranioplasty reduce surgical complexity, decrease operative times, minimize exposure and risk of contamination, and have resulted in improved aesthetic results. However, in creating a prefabricated custom implant using a patient's computed tomography data, a stable, unalterable defect must be clearly defined before surgery. In the event that an intraoperative modification of an exiting skull defect is required, or in cases of tumour resection in which the size of the skull defect is unknown preoperatively, these prefabricated implants cannot be used. The ideal method for alloplastic cranioplasty would enable cost-effective creation of a patient-specific implant with the capacity for intraoperative modification. The present article describes a novel technique of cranioplasty that uses a patient's computed tomography data to create a custom forming tool (ie, mold), enabling intraoperative creation of a patient-specific titanium mesh implant. The utility of these implants in creating a custom reconstructive solution in cases in which the size of the skull defect is unknown preoperatively will be demonstrated using two case presentations.

Bioactive-glass in Oral and Maxillofacial Surgery

The use of synthetic materials to repair craniofacial defects is increasing today and will increase further in the future. Because of the complexity of the anatomy in the head and neck region, reconstruction and augmentation of this area pose a challenge to the surgeon. This review discusses key facts and applications of traditional reconstruction bone substitutes, also offering comparative information. It then describes the properties and clinical applications of bioactive-glass (B-G) and its variants in oral and maxillofacial surgery, and provides clinical findings. The discussion of each compound includes a description of its composition and structure, the advantages and shortcomings of the material, and its current uses in the field of osteoplastic and reconstructive surgery. With a better understanding of the available alloplastic implants, the surgeon can make a more informed decision as to which implant would be most suitable in a particular patient.

A technique for intraoperative creation of patient-specific titanium mesh implants

Prefabricated, patient-specific alloplastic implants for cranioplasty reduce surgical complexity, decrease operative times, minimize exposure and risk of contamination, and have resulted in improved aesthetic results. However, in creating a prefabricated custom implant using a patient's computed tomography data, a stable, unalterable defect must be clearly defined before surgery. In the event that an intraoperative modification of an exiting skull defect is required, or in cases of tumour resection in which the size of the skull defect is unknown preoperatively, these prefabricated implants cannot be used. The ideal method for alloplastic cranioplasty would enable cost-effective creation of a patient-specific implant with the capacity for intraoperative modification.

The present article describes a novel technique of cranioplasty that uses a patient's computed tomography data to create a custom forming tool (ie, mold), enabling intraoperative creation of a patient-specific titanium mesh implant. The utility of these implants in creating a custom reconstructive solution in cases in which the size of the skull defect is unknown preoperatively will be demonstrated using two case presentations.

Skull Reconstruction with Custom Made Three-Dimensional Titanium Implant

Background

Source material used to fill calvarial defects includes autologous bones and synthetic alternatives. While autologous bone is preferable to synthetic material, autologous reconstruction is not always feasible due to defect size, unacceptable donor-site morbidity, and other issues. Today, advanced three-dimensional (3D) printing techniques allow for fabrication of titanium implants customized to the exact need of individual patients with calvarial defects. In this report, we present three cases of calvarial reconstructions using 3D-printed porous titanium implants.

Methods

From 2013 through 2014, three calvarial defects were repaired using custommade 3D porous titanium implants. The defects were due either to traumatic subdural hematoma or to meningioma and were located in parieto-occipital, fronto-temporo-parietal, and parieto-temporal areas. The implants were prepared using individual 3D computed tomography (CT) data, Mimics software, and an electron beam melting machine. For each patient, several designs of the implant were evaluated against 3D-printed skull models. All three cases had a custom-made 3D porous titanium implant laid on the defect and rigid fixation was done with 8 mm screws.

Results

The custom-made 3D implants fit each patient's skull defect precisely without any dead space. The operative site healed without any specific complications. Postoperative CTs revealed the implants to be in correct position.

Conclusion

An autologous graft is not a feasible option in the reconstruction of large calvarial defects. Ideally, synthetic materials for calvarial reconstruction should be easily applicable, durable, and strong. In these aspects, a 3D titanium implant can be an optimal source material in calvarial reconstruction.

Cranial suture-like gap and bone regeneration after transplantation of cryopreserved MSCs by use of a programmed freezer with magnetic field in rats

Mesenchymal stem cells (MSCs) can be used for regeneration of various organs and tissues. A previous study revealed that cryopreserved MSCs, which were frozen by a programmed freezer with a magnetic field (Cells Alive System: CAS) and cryopreserved for 7 days in a -150°C deep freezer, can maintain high survival and proliferation rates while retaining both adipogenic and osteogenic differentiation abilities. The purpose of this study was to examine MSC viability and tissue regenerative ability after long-term cryopreservation using a CAS freezer. MSCs were isolated from rat femora bone marrow and cryopreserved in a -150°C deep freezer (CAS group) or directly cryopreserved in a deep freezer (Direct group). After 3 years, the cells were thawed and the number of viable cells was counted. Cell proliferation was also examined after 14 days in culture. For histological examination, forty 4-week-old Fischer 344 male rats received bone and sagittal suture defects with a diameter of 6.0mm, and MSCs (CAS or Direct group) cryopreserved for 1 year were grafted with membranes. Non-cryopreserved MSCs (Control group) were transplanted to an additional twenty rats. The rats were sacrificed at 4, 8, 16, and 24 weeks after surgery. The parietal bones, including the sagittal suture, were observed under a light microscope and the extent of bone regeneration was measured. Our results indicate that MSCs survival and proliferation rates were significantly higher in the CAS group than in the Direct group. In the Control and CAS groups, a large amount of new bone formation and a suture-like gap was identified 24 weeks after transplantation, whereas only a small amount of new bone formation was observed in the Direct group. These results suggest that the CAS freezer is amenable to long-term cryopreservation of MSCs, which can be applied to the regeneration of various tissues, including bone tissue with suture-like gap formation.

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.

A comparison between autograft alone, bone cement, and demineralized bone matrix in cranioplasty

OBJECTIVES

To compare bone autograft, bone cement, and demineralized bone matrix in functional and aesthetic outcomes and complications following cranioplasty for reconstruction of cranial defects.

STUDY DESIGN

Retrospective chart review.

MATERIALS AND METHODS

A retrospective chart review was performed of patients who underwent cranioplasty at a single institution between 1992 and 2012. The patients were divided based on whether bone autograft, demineralized bone matrix, or bone cement was used for reconstruction of their craniofacial defect. Demographics and diagnosis data were collected. Complications and cosmetic outcomes were examined for each group.

RESULTS

There was no significant difference between groups regarding follow-up and age at time of surgery. The bone cement group had a higher infection rate. There was more dehiscence and scalp scarring in the autograft and bone cement groups. However, residual bone defects and the need for a revision cranioplasty were higher in the bone matrix group. Likewise, patient, parent, and surgeon satisfaction with the appearance was lower in the bone matrix group.

CONCLUSIONS

There appears to be a trend toward a lower success rate in patients with fibroblast growth factor receptor-related craniosynostosis and in those reconstructed with bone matrix compared to bone autograft and bone cement.

LEVEL OF EVIDENCE

4.

Role of a dentist in comprehensive management of a comatose patient with post traumatic head injury and neuropathological chewing

Injury of the head and neck region can result in substantial morbidity. Comprehensive management of such patients requires team work of several specialties, including dentists. A young female patient with extensive loss of cranium and associated pathological chewing was referred to the dental department. The lost cranium was replaced by a custom-made, hand-fabricated cranioplast. Trauma due to pathological mastication was reduced by usage of a custom-made mouthguard. Favorable results were seen in the appearance of the patient and after insertion of the mouthguard as evidenced in good healing response. The intricate role of a dental specialist in the team to manage a patient with post traumatic head injury has been highlighted. The take away message is to make the surgical fraternity aware of the scope of dentistry in the comprehensive management of patients requiring special care.

Intraoperative fabrication of patient-specific moulded implants for skull reconstruction: single-centre experience of 28 cases

BACKGROUND

Intraoperatively fabricated polymethylmethacrylate (PMMA) implants based on computer-designed moulds were used to improve cosmetic results after hard tissue replacement. To assess the implant's cosmetic and functional results we performed both subjective and objective assessments.

METHODS

This retrospective analysis was performed using a cohort of 28 patients who received PMMA implants between February 2009 and March 2012. The cosmetic and functional results were assessed using a patient questionnaire. Furthermore an objective volumetric subtraction score (0-100) was applied and implant thickness, as well as gaps and tiers, were measured.

RESULTS

Patients mainly judged their cosmetic result as "good". Two of the 28 patients found their cosmetic result unfavourable. The functional result and stability was mainly judged to be good. Measurements of implant thickness showed a very high correlation with the thickness of the contralateral bone. Volumetric subtraction led to a median quality of 80 on a scale from 0 to 100. Median gaps around the margins of the implant were 1.5 mm parietally, 1.7 mm frontally and 3.5 mm fronto-orbitally, and median tiers were 1.2 mm, 0 mm and 0 mm respectively. The overall rate of surgical revisions was 10.7 % (three patients). Two patients suffered from wound healing disturbances (7.1 %). The overall complication rate was comparable to other reports in the literature.

CONCLUSIONS

Implantation of intraoperatively fabricated patient-specific moulded implants is a cost-effective and safe technique leading to good clinical results with a low complication rate.