Cranioplasty with split-thickness calvarial bone

Prognosis of Performing Split-Rib Bone Graft for Cranial Bone Defects

BACKGROUND

Frontal sinus anterior wall defects occur because of various diseases, causing not only aesthetic problems, such as forehead bulging and upper eyelid ptosis, but also exerting physical pressure on the brain or optic nerve. Therefore, this study aimed to evaluate the prognosis of performing split-rib bone graft for frontal sinus anterior wall defects.

METHODS

This study included 30 patients who received a split-rib bone graft for a frontal sinus anterior wall defect. The sizes and volumes of the defects and grafts were measured using three-dimensional computed tomography before, after, and every 6 months for 2 years after the surgery. The Medical Imaging Interaction Toolkit was used for analysis.

RESULTS

The average size and volume of the grafts were 27.29 cm 2 and 5.88 cm 3 , whereas they were 23.76 cm 2 and 4.80 cm 3 at 24 months after surgery, respectively. In a graft size and volume of less than 27 cm 2 and 6 cm 3 , respectively, the rate of graft take was greater than 80% during long-term observation. The younger the age, the higher the rate of graft take. No difference was found in the defect causes. Absorption occurred for up to 18 months.

CONCLUSIONS

Frontal bone defect reconstruction revealed the stable results of the split-rib bone graft over a long period when the size and volume were less than 27 cm 2 and 6 cm 3 , respectively. Furthermore, bone resorption was seen in more than 20% to 30% of the patients, and the rate of resorption increased with age; thus, it is appropriate to consider overcorrection and other reconstruction methods.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Fatal non-accidental pediatric cranial fracture risk and three-layered cranial architecture development

This study examines the influence of three-layered cranial architecture development upon blunt force trauma (BFT) cranial outcomes associated with pediatric non-accidental injury (NAI). Macroscopic and microscopic metric and morphological comparisons of subadult crania ranging from perinatal to 17 years of age chronicle the ontogenetic development and spatial and temporal variability in the emergence of a mature cranial architecture. Cranial vault thickness increases with subadult age, accelerating in the first 2 years of life due to rapid brain growth during this period. Three-layer differentiation of the cranial tables and diploë initiates by 3-6 months but is not consistently observed until 18 months to 2 years; diploë formation is not well developed until after age 4 and does not manifest a mature appearance until after age 8. These results allow topographic documentation of cortical and diploic development and temporal and spatial variability across the growing cranium. The lateral cranial vault is identified as expressing delayed development and reduced expression of the three-layer architecture, a pattern that continues into adulthood. Comparison of fracture locations from known BFT pediatric cases with identified cranial fracture high-risk impact regions shows a concordance and suggests the presence of a higher fracture risk associated with non-accidental BFT in the lateral vault region in subadults below the age of 2. The absence or lesser development of a three-layered architecture in subadults leaves their cranial bones, particularly in the lateral vault, thin and vulnerable to the effects of BFT.

Split Calvarial Grafting for Closure of Large Cranial Defects: The Ideal Option?

Among the various cranioplasty options for reconstruction of large post-craniectomy defects, split calvarial grafting offers numerous significant advantages such as the provision of viable autogenous bone graft material comprising of living, immunocompatible bony cells that integrate fully with the skull bone bordering the cranial defect. Its potential for revascularization and subsequent integration and consolidation allows its successful use even in previously infected or otherwise compromised recipient sites. Its excellent contour match at the recipient site and low cost as compared to various alloplastic implant materials often makes it preferable to the latter. Surgeon's skill, dexterity, expertise and experience are important factors to be considered in this highly technique-sensitive procedure.

Incomplete reossification after craniosynostosis surgery-incidence and analysis of risk factors: a clinical-radiological assessment study

OBJECTIVE One of the principles of the surgical treatment of craniosynostosis includes the release of fused bone plates to prevent recurrence. Such bone defects require a reossification process after surgery to prevent a cosmetic problem or brain vulnerability to damage. The objective of this study is to describe and analyze the radiological and clinical evolution of bone defects after craniosynostosis. METHODS From January 2005 to May 2016, 248 infants underwent surgical correction of craniosynostosis at HUiP La Fe Valencia; the authors analyzed data from 216 of these cases that met the inclusion criteria for this study. Various surgical techniques were used according to the age of the patient and severity of the case, including endoscopic-assisted suturectomy, open suturectomy, fronto-orbital advancement, and cranial vault remodeling. Clinical follow-up and radiological quantitative measurements in 2 periods-12-24 months and 2 years after surgery-were analyzed; 94 patients had a postoperative CT scan and were included in the radiological analysis. RESULTS At the end of the follow-up period, 92 of 216 patients (42.59%) showed complete closure of the bone defect, 112 patients (51.85%) had minor bone defects, and 12 patients (5.56%) had significant bone defects that required surgical intervention. In the multivariate analysis, age at first surgery was not significantly associated with incomplete reossification (p = 0.15), nor was surgical site infection (p = 0.75). Multivariate analysis identified area of cranial defect greater than 5 cm² in the first CT scan as predictive of incomplete reossification (p = 0.04). The mean area of cranial defect in the first CT scan (12-24 months after surgery) was 3.69 cm² in patients treated with open surgery and 7.13 cm² in those treated with endoscopic-assisted procedures; in the multivariate analysis, type of procedure was not related to incomplete reossification (p = 0.46). The positive predictive value of palpation as evaluation of bone cranial defects was 50% for significant defects and 71% for minor defects. CONCLUSIONS The incidence of cranial defects due to incomplete reossification requiring cranioplasty was 5.56% in our series. Defects greater than 5 cm² in the first postoperative CT scan showed a positive association with incomplete reossification. Patients treated with endoscope-assisted procedures had larger defects in the initial follow-up, but the final incidence of cranial defects was not significantly different in the endoscope-assisted surgery group from that in the open surgery group.

Reconstruction of Large Calvarial Defects Using Titanium Mesh Versus Autologous Split Thickness Calvarial Bone Grafts: A Comprehensive Comparative Evaluation of the Two Major Cranioplasty Techniques

Background

Both alloplastic 3-D dynamic titanium mesh implants and Autogenous split calvarial cortico-cancellous bone grafts have been extensively used for cranial defect reconstruction. Whether either method is procedurally, cosmetically or therapeutically superior to the other, has rarely been studied or evaluated.

Aim

The aim of the study was to objectively examine, assess, evaluate and compare the procedural ease, convenience, safety and versatility of cranioplasty performed using titanium mesh implants versus split calvarial grafts and to compare the intra- and post-operative complications encountered, and the cosmetic and therapeutic outcomes achieved using these two cranioplasty techniques.

Material and Methods

A retrospective analysis was carried out on 40 patients with large post-craniectomy defects, who underwent cranioplasty between 2012 and 2016. Twenty patients underwent cranioplasty with titanium mesh implants and 20 with split calvarial cortico-cancellous bone grafts. Post-operative follow-up ranged from 1 to 5 years and the patients were observed (clinically as well as by means of radiographs and CT scans) for cosmetic, functional and neurological improvements.

Results

Titanium mesh cranioplasty afforded more benefits, such as a shorter operating time, ease in manipulation, absence of donor-site morbidity, usefulness in previously infected or compromised recipient sites, absence of the risk of graft resorption or rejection, and a ready means to aspirate any post-operative epidural collection through its mesh structure. It also compared favorably when the cranial defects were large, owing to its, so to speak, limitless supply viz a viz, the relative paucity of harvestable split calvarial bone autograft.

Conclusion

Both modalities have their pros and cons. Split calvarial grafting is the more physiologic and less expensive option, useful for small- to medium-sized defects, while titanium mesh is the safer, more versatile, reliable and often preferred option, particularly when the cranial defects are large and also in severe head injury patients in whom harvesting calvarial bone could further compromise the already traumatized calvarium with possible stress fractures, further endangering its vital contents.

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.

Analysis of the factors affecting outcome after combat-related cranial defect reconstruction

INTRODUCTION

Reports on the outcomes of cranioplasty after combat-related injuries are relatively rare in the current literature. We present our results on the reconstruction of cranial defects resulting from injuries sustained in combat, comparing outcomes using autologous (iliac bone) grafts or (acrylate) allografts, and analysis of other factors that may influence the final outcome.

MATERIAL AND METHODS

The study comprised 207 patients with cranial defects resulting from combat-related injuries, repaired with autografts or allografts. The final outcome was defined at least 5 years postoperatively on the basis of cosmetic restoration and the existence of complications as successful (acceptable cosmetic restoration + absence of complications) or unsuccessful (poor cosmetic restoration or acceptable cosmetic restoration + complications).

RESULTS

Successful outcomes were achieved in 83.6% of patients; there was no operative mortality. There were 25 instances of complications: postoperative infection (n = 15, allograft (7/53), autograft (8/154)), autograft resorption (n = 8), and in two cases, graft luxation. Poor cosmetic restoration was noted in 9 (4.3%) patients who had received an autograft.

CONCLUSIONS

Thin and poorly vascularized skin, a surface area of the defect larger than 88 cm², previous local infection and communication with paranasal cavities significantly influenced outcomes after combat-related cranioplasty, the final three being independent predictors of an unsuccessful outcome.

Rare giant frontal sinus osteoma mimicking fibrous dysplasia

OBJECTIVE

To present the first report of a giant frontal sinus osteoma treated by excision and single-stage reconstruction with custom-made titanium cranioplasty and left orbital roof prostheses.

CASE REPORT

A 31-year-old man with a history of chronic frontal sinusitis presented with a deforming, painless, midline forehead swelling of 11 years' duration, which had been treated unsuccessfully in Nigeria. Differential diagnosis included both benign and malignant bony tumours. Computerised tomography revealed a giant bony frontal sinus tumour extending beyond the sinus roof and breaching the left orbit, consistent with fibrous dysplasia. Given the extent of the tumour, open craniectomy was performed for surgical extirpation. Histological analysis identified multiple osteomas. This surgical approach achieved excellent cosmesis, with no evidence of recurrence at 12-month follow up.

CONCLUSION

Forehead swelling may pose diagnostic and management dilemmas for the ENT surgeon; however, effective management is facilitated by a multidisciplinary approach.

Changes in graft thickness after skull defect reconstruction with autogenous split calvarial bone graft

The ideal material for primary reconstruction of skull defect would be the autogenous bone. However, the long-term evaluation regarding the change in bone graft thickness has not been reported. In this article, we analyzed the thickness changes of the graft according to the time period. Between March 2005 and February 2011, a total of 29 patients underwent skull reconstruction with autogenous split calvarial bone grafts. After applying exclusion criteria, computed tomographic (CT) images of 15 patients were analyzed. The donor bone was harvested in full thickness as 1 piece and then as split. One half of the bone plate was transferred to the defect site; the other half, to the donor site. Both halves were fixed with titanium plates. To compare graft thickness changes, immediate postoperative and follow-up CT scans were analyzed by a single researcher. An anatomic reference was appointed for each patient, and the thickness of the graft on the same level was measured on time-series CT images. Collected data were analyzed with a polynomial random coefficient model. The main causes of the skull defects were trauma and tumor excision. In all cases, the graft thickness was not decreased but even increased in both the donor and recipient sites. The mean graft thicknesses between 6 months and 1 year after the surgery as well as those between 2 and 3 years after the surgery were 1.24-times and 1.56-times thicker than the immediate postoperative thickness, respectively. Graft thickness turned out to be either maintained or increased over time.

Efficacy of Autogenous Split Thickness Calvarial Graft in the Management of Residual Cranial Defect

INTRODUCTION

The patients with cranial deformity suffer from headache, dizziness, irritability, loss of concentration, depression, anxiety, intolerance to noise and vibration and neuromotor weakness. It is therefore essential to restore the calvarium.

MATERIAL AND METHOD

This study was conducted in the Department of Oral and Maxillofacial Surgery, Armed Forces Medical College, Pune between Oct 2010 and Mar 2012. The study population was selected from the outpatient department and from the referred cases. The aim was to study the uptake of split thickness calvarial graft in the management of residual cranial defect. After applying the inclusion and exclusion criterions, ten cases were selected with residual cranial deformity, operated for cranioplasty using split thickness calvarial graft and evaluated.

CONCLUSION

It was concluded that cranioplasty using autogenous split thickness calvarial graft for restoring cranial defects is a useful technique and this procedure allows the surgeon to reconstruct a moderate-to-large cranial defect, without breaching the inner cortical plate.

Cranioplasty Using a Modified Split Calvarial Graft Technique in Cleidocranial Dysplasia

Cleidocranial dysplasia is a well-documented rare autosomal dominant skeletal dysplasia characterized by hypoplastic/aplastic clavicles, brachycephalic skull, patent sutures and fontanelles, midface hypoplasia, and abnormalities of dentition. Patients with cleidocranial dysplasia often complain about undesirable esthetic appearance of their forehead and skull. Notwithstanding many studies of molecular, genetics and skeletal abnormalities of this congenial disorder, there have been very few written reports of cranioplasty involving cleidocranial dysplasia. Thus, we report a rare case of successful cranioplasty using a modified split calvarial graft technique in patient with cleidocranial dysplasia.

Reconstructive approach to hostile cranioplasty: A review of the University of Chicago experience

BACKGROUND

Hostile sites for cranioplasty occur in patients with a history of radiation, infection, failed cranioplasty, CSF leak or acute infection. We review our series of autologous cranioplasties and present an approach to decision-making for reconstructing these complex defects.

METHODS

Patients with cranioplasty of a hostile cranial site at the University of Chicago between 2003 and 2012 were identified. They were stratified into three groups: chimeric free flap with vascularized bone (the vascular group), non-vascularized bone with local coverage (the non-vascular group) and non-vascularized bone with free flap (the mixed group). The primary outcome measure was a major complication in the year following cranioplasty, identified by flap or bone graft failure.

RESULTS

We reviewed 33 cases; 14 "vascular", 13 "non-vascular", and 8 "mixed". There was no difference in flap or bone graft failure rates, which were 7% (1/14) for the vascular group, 8% (1/13) for the non-vascular group, and 0% for the mixed group (p = NS). Overall complication rate was statistically different between the three groups (p = 0.01). The non-vascular group had the lowest complication rate (31%). Based on our data we developed an assessment score (The University of Chicago CRAnial Severity Score of Hostility, CRASSH) for patient and treatment stratification.

CONCLUSIONS

Vascularized, non-vascularized and mixed reconstructive methods can be used successfully in these challenging situations. We offer the CRASSH to aid in aligning patients with the most appropriate autologous reconstruction method for their hostile cranial sites.

Transforming growth factor beta 1 augments calvarial defect healing and promotes suture regeneration

BACKGROUND

Repair of complex cranial defects is hindered by a paucity of appropriate donor tissue. Bone morphogenetic protein 2 (BMP2) and transforming growth factor beta 1 (TGFβ1) have been shown separately to induce bone formation through physiologically distinct mechanisms and potentially improve surgical outcome for cranial defect repair by obviating the need for donor tissue. We hypothesize that a combination of BMP2 and TGFβ1 would improve calvarial defect healing by augmenting physiologic osteogenic mechanisms.

METHODS/RESULTS

Coronal suturectomies (3×15 mm) were performed in 10-day-old New Zealand White rabbits. DermaMatrix™ (3×15mm) patterned with four treatments (vehicle, 350 ng BMP2, 200 ng TGFβ1, or 350 ng BMP2+200 ng TGFβ1) was placed in suturectomy sites and rabbits were euthanized at 6 weeks of age. Two-dimensional (2D) defect healing, bone volume, and bone density were quantified by computed tomography. Regenerated bone was qualitatively assessed histologically. One-way analysis of variance revealed significant group main effects for all bone quantity measures. Analysis revealed significant differences in 2D defect healing, bone volume, and bone density between the control group and all treatment groups, but no significant differences were detected among the three growth factor treatment groups. Qualitatively, TGFβ1 treatment produced bone with morphology most similar to native bone. TGFβ1-regenerated bone contained a suture-like tissue, growing from the lateral edge of the defect margin toward the midline. Unique to the BMP2 treatment group, regenerated bone contained lacunae with chondrocytes, demonstrating the presence of endochondral ossification.

CONCLUSIONS/SIGNIFICANCE

Total healing in BMP2 and TGFβ1 treatment groups is not significantly different. The combination of BMP2+TGFβ1 did not significantly increase bone healing compared with treatment with BMP2 or TGFβ1 alone postoperatively at 4 weeks. We highlight the potential use of TGFβ1 to regenerate calvarial bone and cranial sutures. TGFβ1 therapy significantly augmented bony defect healing at an earlier time point when compared with control, regenerated bone along the native intramembranous ossification pathway, and (unlike BMP2 alone or in combination with TGFβ1) permitted normal suture reformation. We propose a novel method of craniofacial bone regeneration using low-dose, spatially controlled growth factor therapies to minimize potentially harmful effects while maximizing local bioavailability and regenerating native tissues.

Cranioplasty for large-sized calvarial defects in the pediatric population: a review

Large-sized calvarial defects in pediatric patients pose a reconstructive challenge because of children's unique physiology, developing anatomy, and dynamic growth. We review the current literature and outcomes with autologous and alloplastic cranioplasty in the pediatric population.

Use of a customized 3D "basket" to create a solitary split-thickness cranial graft from numerous split fragments in an infant

While autologous split calvaria remains the preferred material for use in pediatric cranioplasty, it may be difficult to split the bone neatly into two distinct pieces, especially in infants and young children. In this paper, the authors present a technique in which numerous split pieces of bone can be readily joined together and conformed to the shape of the specific defect using a customized template and 3D trellis-like basket.

Cranioplasty with custom-made titanium plates--14 years experience

BACKGROUND

There is no consensus on which material is best suited for repair of cranial defects.

OBJECTIVE

To investigate the outcomes following custom-made titanium cranioplasty.

METHODS

The medical records for all patients who had titanium cranioplasty at 2 major neurosurgical centers in Western Australia were retrieved and analyzed for this retrospective cohort study.

RESULTS

Altogether, 127 custom-made titanium cranioplasties on 113 patients were included. Two patients had 3 titanium cranioplasties and 10 patients had 2. Infected bone flap (n = 61, 54%), either from previous craniotomy or autologous cranioplasty, and contaminated bone flap (n = 16, 14%) from the initial injury were the main reasons for requiring titanium cranioplasty. Complications attributed to titanium cranioplasty were common (n = 33, 29%), with infection being the most frequent complication (n = 18 patients, 16%). Complications were, on average, associated with an extra 7 days of hospital stay (interquartile range 2-17). The use of titanium as the material for the initial cranioplasty (P = .58), the presence of skull fracture(s) (P > .99) or scalp laceration(s) (P = .32) at the original surgery, and proven local infection before titanium cranioplasty (P = .78) were not significantly associated with an increased risk of infection. Infection was significantly more common after titanium cranioplasty for large defects (hemicraniectomy [39%] and bifrontal craniectomy [28%]) than after cranioplasty for small defects (P = .04).

CONCLUSION

Complications after using titanium plate for primary or secondary cranioplasty were common (29%) and associated with an increased length of hospital stay. Infection was a major complication (16%), and this suggested that more vigorous perioperative infection prophylaxis is needed for titanium plate cranioplasty.

Fragmented adipose tissue graft for bone healing: histological and histometric study in rabbits' calvaria

Objective The adipose tissue represents an important reservoir of stem cells. There are few studies in the literature with which to histologically evaluate whether or not the adipose tissue graft is really a safe option to achieve bone repair. This study histologically analyzed the effect of fragmented autogenous adipose tissue grafts on bone healing in surgically created, critical-size defects (CSD) in a rabbit’s calvaria. Study design Forty-two New Zealand rabbits were used in this study. CSD that were 15 mm in diameter were created in the calvarium of each animal. The defects were randomly divided into two groups: in Group C (control), the defect was filled only by a blood clot and, in Group FAT (i.e., fragmented adipose tissue), the defect was filled with fragmented autogenous adipose tissue grafts. The groups were divided into subgroups (n = 7) for euthanasia at 7, 15, and 40 days after the procedure had been conducted. Histologic and histometric analyses were performed. Data were statistically analysed with ANOVA and Tukey’s tests (p < 0.05). Results The amount of bone formation did not show statistically significant differences seven days after the operation, which indicates that the groups had similar amounts of mineral deposition in the earlier period of the repair. Conversely, a significant of amount of bone matrix deposition was identified in the FAT group at 15 and 40 days following the operation, both on the border and in the body of the defect. Such an outcome was not found in the control group. Conclusion In this study, an autologous adipose tissue graft may be considered as likely biomaterial for bone regeneration, since it positively affected the amount of bone formation in surgically created CSD in the rabbits’ calvaria 40 days after the procedure had been performed. Further investigations with a longer time evaluation are warranted to determine the effectiveness of autologous adipose tissue graft in the bone healing.

Key words:Adipose tissue, bone regeneration, rabbits, critical defects.

Anterior cranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graft

Background

Cranial base defects are challenging to reconstruct without serious complications. Although free tissue transfer has been used widely and efficiently, it still has the limitation of requiring a long operation time along with the burden of microanastomosis and donor site morbidity. We propose using a reverse temporalis muscle flap and calvarial bone graft as an alternative option to a free flap for anterior cranial base reconstruction.

Methods

Between April 2009 and February 2012, cranial base reconstructions using an autologous calvarial split bone graft combined with a reverse temporalis muscle flap were performed in five patients. Medical records were retrospectively analyzed and postoperative computed tomography scans, magnetic resonance imaging, and angiography findings were examined to evaluate graft survival and flap viability.

Results

The mean follow-up period was 11.8 months and the mean operation time for reconstruction was 8.4±3.36 hours. The defects involved the anterior cranial base, including the orbital roof and the frontal and ethmoidal sinus. All reconstructions were successful. Viable flap vascularity and bone survival were observed. There were no serious complications except for acceptable donor site depressions, which were easily corrected with minor procedures.

Conclusions

The reverse temporalis muscle flap could provide sufficient bulkiness to fill dead space and sufficient vascularity to endure infection. The calvarial bone graft provides a rigid framework, which is critical for maintaining the cranial base structure. Combined anterior cranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graft could be a viable alternative to free tissue transfer.

Split calvarial bone graft for the reconstruction of skull defects

Cranioplasty is a common, but formidable surgical procedure for neurosurgeons, in patients with scalp and / or calvarial defects. This procedure can be simple or complex. The main objectives of cranioplasty are: To achieve primary wound healing, obliterate dead space, and seal off sterile cranial areas from contaminated oronasal cavities, to restore the normal barriers protecting the intracranial structures (together with a satisfactory cosmetic result) and obtain a permanent or very durable reconstruction, using biologically inert materials, and also to restore the aesthetics. The greatest problem is selecting the optimum material for repair of the cranial defect. Many synthetic substitutions of the dura and bone are often used for reconstruction of the skull base; unfortunately, these methods bear significant disadvantages and can induce chronic inflammation, carry a high risk of infection, and are inferior to biological sources in terms of strength and sealing quality [with the exception of some materials, such as titanium mashes and CortossTM (Orthovita®, Malvern, USA), which are seen to have more strength than the thin split thickness calvarial bone]. The primary aim of this article is to review the basic principles to use the split calvarial graft for the reconstruction of the skull defect.

Split calvarial bone grafting in patients less than 1 year of age: technical note and use in craniofacial surgery for craniosynostosis

PURPOSE

The material of choice for filling cranial defects is autologous split calvarial bone. Up to now, the thin calvarial bone and lack of diploic space in very young children has led surgeons to believe that harvesting of split calvarial grafts can generally not be done under the age of 2 years. We describe a simple technique for successful harvesting of split cranial vault bone in infants less than 1 year of age.

METHODS

This procedure involves squeezing the bone to shear the outer from the inner table, followed by the use of thin sharp osteotomes. This technique has been used most often in fronto-orbital advancement operations for coronal and metopic synostosis.

RESULTS

In this series of ten such patients, there was no resorption of the split calvarial grafts.

CONCLUSIONS

Splitting of the cranial vault bone can be performed on infants as young as 9 months with good results.

Calcium phosphate cements in skull reconstruction: a meta-analysis

BACKGROUND

This work addresses the controversy regarding the indications and results of calcium phosphate cements in skull reconstruction through a meta-analysis of the published literature.

METHODS

A PubMed search for articles reporting the use of calcium phosphate cements for skull reconstruction was performed. Data collected included age, volume of cement, defect size, material used, length of follow-up, placement in communication with paranasal sinuses or in irradiated fields, and complications.

RESULTS

Nineteen articles met the authors' inclusion criteria. The mean rates of complications were as follows: total complications, 13 percent (range, 0 to 62 percent); major complications, 9 percent (range, 0 to 62 percent); minor complications, 2 percent (range, 0 to 5 percent); infection, 5 percent (range, 0 to 22 percent); reoperation, 14 percent (range, 0 to 62 percent); and secondary surgery for contour correction, 1 percent (range, 0 to 12 percent). There was significant heterogeneity in the estimated rate of total and major complications, infection, and reoperation (p < 0.001), but minor complications and secondary contour correction had less heterogeneity (p = 0.58 and p = 0.78, respectively). Radiotherapy and communication with the paranasal sinuses significantly increased the complication rate (p < 0.05). Duration between surgery and complications averaged 17.5 months (range, 1 to 89 months).

CONCLUSIONS

When mean complication rate and complication range of calcium phosphate cements in our meta-analysis were compared with previous large cranioplasty studies using methylmethacrylate or autogenous bone, calcium phosphate fared no better, and sometimes fared worse, than these other modalities. Calcium phosphate, therefore, should only be used selectively, and prospective long-term studies are needed to further refine its role in skull reconstruction.

RECURRING OSTEOMA WITHIN A CALCIUM PHOSPHATE BONE CEMENT CRANIOPLASTY

OBJECTIVE

We present a unique case of a recurrent osteoma within a cranioplasty performed with calcium phosphate bone cement.

CLINICAL PRESENTATION

The patient is a 7-year-old boy who had initially undergone a craniotomy for resection of a frontal cranial tumor followed by a cranioplasty with artificial bone matrix. On routine follow-up evaluation 2 years later, the patient had a mass expanding from the cranioplasty.

INTERVENTION

At the time of reoperation, the patient was found to have a histopathologically confirmed recurrent osteoma within the artificial bone matrix. The patient later underwent repair of the frontal cranial defect using a patient-specific implant.

CONCLUSION

We discuss this unusual case, treatment, and possible causes. We believe that a safety margin and curettage of the resection border as well as resection of the overlying periosteum might prevent recurrence.

Autologous stem cells (adipose) and fibrin glue used to treat widespread traumatic calvarial defects: case report

This is a report of a 7-year-old girl suffering from widespread calvarial defects after severe head injury with multifragment calvarial fractures, decompressive craniectomy for refractory intracranial hypertension and replantation of cryopreserved skull fragments. Chronic infection resulted in an unstable skull with marked bony defects. Two years after the initial injury the calvarial defects were repaired. Due to the limited amount of autologous cancellous bone available from the iliac crest, autologous adipose derived stem cells were processed simultaneously and applied to the calvarial defects in a single operative procedure. The stem cells were kept in place using autologous fibrin glue. Mechanical fixation was achieved by two large, resorbable macroporous sheets acting as a soft tissue barrier at the same time. The postoperative course was uneventful and CT-scans showed new bone formation and near complete calvarial continuity three months after the reconstruction.

Bone autografting of the calvaria and craniofacial skeleton: historical background, surgical results in a series of 15 patients, and review of the literature

BACKGROUND

Although the use of autologous bone for reconstruction of the cranial and facial skeleton underwent a partial reappraisal following the introduction of a vast range of alloplastic materials for this purpose, it has demonstrated definite advantages over the last century and, particularly, during the last decade.

METHODS

Fifteen patients underwent cranial and/or cranio-facial reconstruction using autologous bone grafting in the Department of Neurologic Sciences-Neurosurgery and the Division of Maxillo-Facial Surgery of the Rome "La Sapienza" University between 1987 and 1995. This group of patients consisted of 8 females and 7 males whose average age was 29.5 years (range 7.5 to 59 years, mean age 30). In all these patients cranioplasty and/or cranio-facial reconstruction had been performed to repair bone defects secondary to benign tumors or tumor-like lesions (12 cases), trauma (2 cases), or, in the remaining case, to wound infection after craniotomy for a neurosurgical operation.

RESULTS

The results obtained in a series of 15 patients treated using this method are described with reference to the abundant data published on this topic.

CONCLUSION

The mechanical, immunologic, and technical-grafting properties of autologous bone, together with its superior esthetic and psychological effects, probably make it the best material for cranioplasty.

Custom-made cast titanium implants produced with CAD/CAM for the reconstruction of cranium defects

Titanium implants for the reconstruction of bony skull defects, using data from three-dimensional spiral computer tomography, have been described by other authors. Instead of milling the implants from a titanium block, an advanced method of rapid prototyping for a fine casting process is presented. Casting vs milling offers several advantages. It is possible to form very thinly tapered structures and to obtain more complex geometrical structures with smaller diameters. Many geometrical forms, which cannot be milled for technical reasons, can be produced using this technique.