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Spontaneous Re-ossification of a Large Calvarial Defect in an Older Child

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... Few studies have reported spontaneous cranial bone regeneration in children over 2 years old. 7 In fact, the capacity of the cranial bone regeneration is largely considered to be absent in children over 6 years old. 8,9 Although Gruber et al. 9 and Bushe 10 have reported cases of spontaneous cranial bone regeneration in patients aged 11 and 17 years respectively, this usually results in an outgrowth of bone at the rim of the craniectomy, thus adding technical difficulty if further surgical closure of the remaining defect is attempted. ...
... Several theories describe the possible factors involved in bone regeneration. Some studies have suggested that the underlying dura mater or the overlying periosteum provide osteoprogenitors for the calvarial bone repair 7,11,12 . However, this hypothesis is based on findings from immature animal and human tissues. ...
... One of them described the phenomenon occurred in a 29-year-old woman [8]. The other three cases were children [9][10][11]. Our case described a woman had spontaneous ossification following craniectomy in her pregnancy period, which we believed to be the first report on this issue. ...
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Introduction and importance Spontaneous bone formation following craniectomy is an extremely rare in adult. As in the medical literature, this is the first case report on total spontaneous ossification following craniectomy in a pregnant woman. Case presentation In this paper, we reported a 20-year-old female currently in the 30th week of her pregnancy suffered from head trauma following motorcycle accident. On admission to our hospital, her GCS score was 3 points. She was treated with emergency extradural hematoma evacuation with craniectomy and Caesarean section with uterine artery ligation. 3 weeks post-operation, the patient and her daughter were discharged from the hospital. At follow-up, spontaneous cranial bone generation was observed. Clinical discussion The presentation, diagnosis and strategy of treatments were discussed. Conclusion Diagnostic imaging in traumatic pregnant patient is often postponed for the concern of fetus exposure to radiation. Traumatic pregnant patient with possible head trauma should be transferred to a center with expertise in neurotrauma and obstetrical care. Spontaneous cranial bone regeneration following craniectomy in adult is rare. Surgery techniques and hormones in pregnancy contribute to bone formation.
... 3 case reports have been published so far in which DC were done in 7 year [4], 8 year [5] and 12 year [6] old patients for traumatic brain injury, brain abscess and Vermian medulloblastoma respectively and which showed spontaneous bone regeneration at craniectomy defect. Our patient is one year old child with bone regeneration after 5 months of craniectomy and progressive improvement in neurological status. ...
... Few studies have reported spontaneous cranial bone regeneration in children over 2 years old. 7 In fact, the capacity of the cranial bone regeneration is largely considered to be absent in children over 6 years old. 8,9 Although Gruber et al. 9 and Bushe 10 and intrinsic reparative potential exist within the suture mesenchyme. ...
... Few studies have reported spontaneous cranial bone regeneration in children over 2 years old. 7 In fact, the capacity of the cranial bone regeneration is largely considered to be absent in children over 6 years old. 8,9 Although Gruber et al. 9 and Bushe 10 and intrinsic reparative potential exist within the suture mesenchyme. ...
Article
Background: In children, decompressive craniectomy is commonly performed in cases of increased intracranial pressure that is not medically managed. Currently, it is standard practice to perform cranioplasty after decompressive craniectomy, although optimal timing for the procedure remains controversial. To date, few studies have reported spontaneous cranial bone regeneration in children without intervention. Case description: A 7-year-old female presented with frontotemporal bone fractures accompanied by dura mater lacerations and brain edema after a motor vehicle accident. She underwent a large decompressive craniectomy and repair of the lacerated dura with a collagen dural substitute. The patient was discharged from the hospital and did not present for follow-up until 10 months after surgery. At that time, computed tomography imaging revealed remarkable spontaneous bone regeneration. With conservative management, she developed enough bone regeneration in the calvarial defect area that cranioplasty surgery was deemed unnecessary. To this date, the patient has no aesthetic deformation of the skull bone and does not exhibit any residual cognitive impairment or motor deficits. Conclusions: This case report shows that cranial bone regeneration is possible in children older than 6 years old, bypassing the need for cranioplasty after decompressive craniectomy. On the basis of this observation, we recommend that more studies should be performed to identify the factors involved in spontaneous skull bone regeneration in the pediatric population.
... In pediatric populations with less adequate donor sites, a particulate calvarial bone graft has been proposed instead of a split calvarial bone graft (Greene et al., 2008;Rogers & Greene, 2012). Spontaneous re-ossification of even large defects is possible in children, although this is rare (Mathew & Chacko, 2008). ...
Thesis
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A cranial bone defect may result after an operative treatment of trauma, infection, vascular insult, or tumor. New biomaterials for cranial bone defect reconstructions are needed for example to mimic the biomechanical properties and structure of cranial bone. A novel glass fiber-reinforced composite implant with bioactive glass particulates (FRC–BG, fiber-reinforced composite–bioactive glass) has osteointegrative potential in a preclinical setting. The aim of the first and second study was to investigate the functionality of a FRC–BG implant in the reconstruction of cranial bone defects. During the years 2007–2014, a prospective clinical trial was conducted in two tertiary level academic institutions (Turku University Hospital and Oulu University Hospital) to evaluate the treatment outcome in 35 patients that underwent a FRC–BG cranioplasty. The treatment outcome was good both in adult and pediatric patients. A number of conventional complications related to cranioplasty were observed. In the third study, a retrospective outcome evaluation of 100 cranioplasty procedures performed in Turku University Hospital between years 2002–2012 was conducted. The experimental fourth study was conducted to test the load-bearing capacity and fracture behavior of FRC–BG implants under static loading. The interconnective bars in the implant structure markedly increased the load-bearing capacity of the implant. A loading test did not demonstrate any protrusions of glass fibers or fiber cut. The fracture type was buckling and delamination. In this study, a postoperative complication requiring a reoperation or removal of the cranioplasty material was observed in one out of five cranioplasty patients. The treatment outcomes of cranioplasty performed with different synthetic materials did not show significant difference when compared with autograft. The FRC–BG implant was demonstrated to be safe and biocompatible biomaterial for large cranial bone defect reconstructions in adult and pediatric patients.
Article
After severe traumatic brain injury, patients often present with signs of increased intracranial hypertension and partially require decompressive craniectomies. Artificial materials are usually required to repair skull defects and spontaneous skull ossification is rarely observed in adults. This study reported a 64-year-old man was admitted to the hospital with a coma due to a traffic accident. Emergency computed tomography (CT) examination upon admission showed a left temporo-occipital epidural hematoma with a cerebral hernia and skull fracture. The patient underwent urgent craniotomy for hematoma removal and decompression under general anesthesia. The patient was discharged after 1 month of treatment. The patient returned to the hospital for skull repair 145 days after the craniotomy. Pre-operative CT showed island skull regeneration in the skull defect area; therefore, skull repair was postponed after clinical evaluation. Regular follow-up is required. Twenty-three months after surgery, head CT showed that the new skull had completely covered the defect area. We collected other 11 similar cases of spontaneous human skull regeneration in a literature search to analyze the possible factors impacting skull regeneration. The analysis of the cases indicated that maintaining the integrity of the periosteum, dura, and blood vessels during craniotomy may play an important role in skull regeneration. Skull regeneration predominantly occurs in young patients with rapid growth and development; therefore, an appropriate postponement of the cranioplasty time under close monitoring could be considered for young patients with skull defects.
Article
We report a 29-year-old woman with the diagnosis of acute subdural hematoma and brain edema. She underwent emergency decompressive craniectomy and evacuation of hematoma. Two years later, follow-up showed a well-formed bone along the craniectomy site. To our knowledge, this is the first case report with total spontaneous re-ossification in adults. We review literature and suggest the physiology of the process. Pericraneum, diploë and, above all, dura mater collaborate in spontaneous bone formation. All these layers are very important, and they must be respected during dissection.
Article
The experience acquired during 10 years treatment of 33 children having undergone a large craniectomy with an average follow-up time of 5.3 years is presented. Different methods of primary and delayed closure of the skull defect are documented and discussed. Whenever possible the deep frozen conserved skull flap was reimplanted. The problem of skull flap resorption and insufficient spontaneous ossification and the alternative of a heterologous cranioplasty with methylmethacrylate (MMA) in cases of insufficient reossification is considered. The decision to use MMA as a secondary skull defect graft should be delayed at least one year after craniectomy, since a spontaneous reossification of the defect is possible until adolescence.
Article
In an animal model, the effect of transferring mature pericranial tissues to immature animals with cranial bone defects was tested. Isogeneic guinea pigs of different ages were used: "infants" (3-4 weeks) and "adults" (> 18 months). Bilateral parietal cranial defects were made in infant guinea pigs and the guinea pigs were divided into three groups. In group 1 (n = 6), the infant periosteum was resected and replaced as an autograft on one side (control), and adult periosteum was transplanted as an isograft on the other (experiment). In group 2 (n = 5), dura was used as the variable. In group 3 (n = 5), combined dura and periosteum were the variables. After 8 weeks, there was complete or near complete bone regeneration in all animals in which infant dura was present. There was minimal to no bone regeneration in defects in which adult dura was present. Unlike dura, periosteum had little influence on the capacity of the bone to regenerate.
Article
The ability of newborns and immature animals to reossify calvarial defects has been well described. This capacity is generally lost in children greater than 2 years of age and in mature animals. The dura mater has been implicated as a regulator of calvarial reossification. To date, however, few studies have attempted to identify biomolecular differences in the dura mater that enable immature, but not mature, dura to induce osteogenesis. The purpose of these studies was to analyze metabolic characteristics, protein/gene expression, and capacity to form mineralized bone nodules of cells derived from immature and mature dura mater. Transforming growth factor beta-1, basic fibroblast growth factor, collagen type IalphaI, osteocalcin, and alkaline phosphatase are critical growth factors and extracellular matrix proteins essential for successful osteogenesis. In this study, we have characterized the proliferation rates of immature (6-day-old rats, n = 40) and mature (adult rats, n = 10) dura cell cultures. In addition, we analyzed the expression of transforming growth factor beta-1, basic fibroblast growth factor-2, proliferating cell nuclear antigen, and alkaline phosphatase. Our in vitro findings were corroborated with Northern blot analysis of mRNA expression in total cellular RNA isolated from snap-frozen age-matched dural tissues (6-day-old rats, n = 60; adult rats, n = 10). Finally, the capacity of cultured dural cells to form mineralized bone nodules was assessed. We demonstrated that immature dural cells proliferate significantly faster and produce significantly more proliferating cell nuclear antigen than mature dural cells (p < 0.01). Additionally, immature dural cells produce significantly greater amounts of transforming growth factor beta-1, basic fibroblast growth factor-2, and alkaline phosphatase (p < 0.01). Furthermore, Northern blot analysis of RNA isolated from immature and mature dural tissues demonstrated a greater than 9-fold, 8-fold, and 21-fold increase in transforming growth factor beta-1, osteocalcin, and collagen IalphaI gene expression, respectively, in immature as compared with mature dura mater. Finally, in keeping with their in vivo phenotype, immature dural cells formed large calcified bone nodules in vitro, whereas mature dural cells failed to form bone nodules even with extended culture. These studies suggest that differential expression of growth factors and extracellular matrix molecules may be a critical difference between the osteoinductive capacity of immature and mature dura mater. Finally, we believe that the biomolecular bone- and matrix-inducing phenotype of immature dura mater regulates the ability of young children and immature animals to heal calvarial defects.
Article
Transforming growth factor-betas (TGF-beta) have been demontstrated to be upregulated during osteoblast function in vitro and during cranial suture fusion in vivo. The authors hypothesized that spontaneous reossification of calvarial defects was also associated with upregulation of TGF-beta. The present study was designed to (1) evaluate the concept of a critical-size defect within the calvaria in an adult guinea pig model and (2) investigate the association between the ossification of calvarial defects and TGF-beta upregulation. Paired circular parietal defects with diameters of 3 and 5 mm and single parietal defects with diameters of 8 or 12 mm were made in 45 six-month-old skeletally mature guinea pigs. Three animals per defect size were killed after survival periods of 3 days, 1 week, 4 weeks, 8 weeks, or 12 weeks. New bone ingrowth was evaluated by assessing for linear closure by a traditional linear method and by a modified cross-sectional area method using an image analysis system in which the thickness of new bone was taken into account. Immunohistochemistry was performed using rabbit polyclonal antibodies to localize TGF-beta1, -beta2, and -beta3. All specimens were photographed, and the intensity of immunostaining was graded based on subjective photographic assessment by three independent reviewers. No defect demonstrated any measurable bone replacement after a survival period of 3 days. All 3- and 5-mm defects were completely reossified after 12 weeks based on the linear analysis of new bone, indicating these defects to be less than critical size. However, new bone formation in the 5-mm defects never exceeded a mean of 40 percent by cross-sectional area of new bone. Percent of new bone formation by cross-sectional area was significantly higher within 3-mm defects than in all larger defects 4 weeks after the craniotomy, reaching a mean of 89 percent new bone by 12 weeks. Persistent gaps were noted on linear analysis of the 8- and 12-mm wounds by 12 weeks, and mean percent new bone by cross-sectional area remained below 30 percent. Immunolocalization demonstrated osteogenic fronts at the advancing bone edge and the endocranial side, in which the osteoblasts stained strongly for all isoforms of TGF-beta. The intensity of osteoblast expression waned considerably after the majority of the defect had reossified. These data indicate that histometric analysis based on cross-sectional area more accurately reflects the osteogenic potential of a cranial defect than does linear inspection of defect closure. Although the interpretation of immunolocalization studies is highly subjective, independent assessment by three reviewers indicates that isoforms of TGF-beta were upregulated during a limited "window" of time corresponding to the period of active calvarial reossification, and expression of TGF-beta corresponded to osteoblast activity within osteogenic fronts.
Article
Guided bone regeneration is a promising means for reconstructing bone defects in the cranium. The present study was performed to better define those factors that affect osteogenesis in the cranium. The authors studied a single animal model, investigating the contribution of the dura, the pericranium, and the adjacent calvarial bone in the process of calvarial regeneration in both mature and immature animals. Bilateral, 100-mm2, parietal calvariectomies were performed in immature (n = 16) and mature (n = 16) rabbits. Parietal defects were randomized to one of four groups depending on the differential blockade of the dura and/or the pericranium by expanded polytetrafluoroethylene membranes. Animals were humanely killed after 12 weeks, and histometric analysis was performed to quantitate the area of the original bone defect, new bone formation, and new bone density. Bone formation was quantified separately both at the periphery and in the center of the defects. Extrasite bone formation was also quantified both on the dural and on the pericranial sides of the barriers. Bone regeneration was incomplete in all groups over the 12-week study period, indicating that complete bone healing was not observed in any group. The dura was more osteogenic than the pericranium in mature and immature animals, as there was significantly more extrasite bone formed on the dural side in the double expanded polytetrafluoroethylene barrier groups. In both the dural and the double expanded polytetrafluoroethylene barrier groups, dural bone production was significantly greater in immature compared with mature animals. The dura appeared to be the source of central new bone, because dural blockade in the dural and double expanded polytetrafluoroethylene groups resulted in a significant decrease in central bone density in both mature and immature animals. Paradoxically, isolation of the pericranium in mature animals resulted in a significant reduction in total new bone area, whereas pericranial contact appeared to enhance peripheral new bone formation, with the control group having the greatest total new bone area. The present study establishes a model to quantitatively study the process of bone regeneration in calvarial defects and highlights differences in the contribution of the dura and pericranium to calvarial bone regeneration between infant and adult animals. On the basis of these findings, the authors propose that subsequent studies in which permeability of the expanded polytetrafluoroethylene membranes is altered to permit migration of osteoinductive proteins into the defect while blocking prolapse of adjacent soft tissues may help to make guided bone regeneration a realistic alternative for the repair of cranial defects.