Primary Grafting with Autologous Cranial Particulate Bone Prevents Osseous Defects following Fronto-Orbital Advancement:

Calvarial Vault Remodeling Technique for Lambdoid Craniosynostosis

SUMMARY

Premature fusion of the lambdoid suture is the most uncommon single-suture synostosis. It presents with a classic "windswept" appearance, a trapezoid-shaped head, and significant skull asymmetry notable for an ipsilateral mastoid bulge and contralateral frontal bossing. Because of the rarity of lambdoid synostosis, little is known about optimal techniques for its treatment. In particular, the proximity of the lambdoid suture to critical intracranial structures such as the superior sagittal and transverse sinuses represents a potential for significant intraoperative bleeding. Prior work has shown that parietal asymmetry persists after repair in these cases. In this article, the authors present a technique for the treatment of unilateral lambdoid craniosynostosis along with two representative cases. This calvarial vault remodeling technique requires the removal of both ipsilateral and contralateral parietal bones. These are moved across hemispheres and reinset on opposite sides to help correct the parietal asymmetry. Obliquely orientated barrel stave osteotomies are performed to provide a safe mechanism for correction of occipital flattening. The authors' early results show improvement in correction of volume asymmetry 1 year postoperatively relative to patients treated with prior calvarial vault remodeling techniques. The authors believe the technique presented here corrects the windswept appearance in patients with lambdoid craniosynostosis and also reduces the potential for complications. Further work will be necessary to confirm this technique's long-term efficacy in a larger cohort.

Autologous Cranioplasty Using a Dental SafeScraper Device

SUMMARY

Conventional methods to reconstruct cortical bone defects introduced by pediatric cranial vault remodeling (CVR) procedures have shortcomings. Use of bone burr shavings as graft material leads to variable ossification, and harvesting split-thickness cortical grafts is time-intensive and often not possible in thin infant calvaria. Since 2013, the authors' team has used the SafeScraper, originally developed as a dental instrument, to harvest cortical and cancellous bone grafts during CVR. The authors assessed the effectiveness of this technique by analyzing postoperative ossification using computed tomography scans of 52 patients, comparing cohorts treated with the SafeScraper versus those who received conventional methods of cranioplasty during fronto-orbital advancement. The SafeScraper cohort had a greater reduction in total surface area of all defects (-83.1% ± 14.9 versus -68.9% ± 29.8; P = 0.034), demonstrating a greater and more consistent degree of cranial defect ossification compared with conventional methods of cranioplasty, suggesting potential adaptability of this tool. This is the first study that describes the technique and efficacy of the SafeScraper in reducing cranial defects in CVR.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

A systematic review and meta-analysis of factors involved in bone flap resorption after decompressive craniectomy

Decompressive craniectomy (DC) is effective in controlling increasing intracranial pressure determined by a wide range of conditions, mainly traumatic brain injury (TBI) and stroke, and the subsequent cranioplasty (CP) displays potential therapeutic benefit in terms of overall neurological function. While autologous bone flap (ABF) harvested at the time of DC is the ideal material for skull defect reconstruction, it carries several risks. Aseptic bone flap resorption (BFR) is one of the most common complications, often leading to surgical failure. The aim of our study was to systematically review the literature and carry out a meta-analysis of possible factors involved in BFR in patients undergoing ABF cranioplasty after DC. A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. Different medical databases (PubMed, Embase, and Scopus) were screened for eligible scientific reports until April 30th 2021. The following data were collected for meta-analysis to assess their role in BFR: sex, age, the interval time between DC and CP, the presence of systemic factors, the etiology determining the DC, CP surgical time, CP features, VP shunt placement, CP infection. Studies including pediatric patients or with less than 50 patients were excluded. Fifteen studies were included. There was a statistically significant increased incidence of BFR in patients with CPF > 2 compared to patients with CPF ≤ 2 (54.50% and 22.76% respectively, p = 0.010). TBI was a significantly more frequent etiology in the BFR group compared to patients without BFR (61.95% and 47.58% respectively, p < 0.001). Finally, patients with BFR were significantly younger than patients without BFR (39.12 ± 15.36 years and 47.31 ± 14.78 years, respectively, p < 0.001). The funnel plots were largely symmetrical for all the studied factors. Bone flap fragmentation, TBI etiology, and young age significantly increase the risk of bone resorption. Further studies are needed to strengthen our results and to clarify if, in those cases, a synthetic implant for primary CP should be recommended.

Effect of Operative Timing and Bone Grafting on Postoperative Cephalometric Indices in Nonsyndromic Sagittal Synostosis

ABSTRACT

Surgical repair of sagittal suture craniosynostosis is highly variable, and optimal timing/use of bone grafts remains a subset of parameters that continue to be studied. We sought to compare cephalometric outcomes of early surgical intervention without bone grafting compared to later intervention with bone grafting. Patients undergoing primary surgical repair of nonsyndromic sagittal suture craniosynostosis between 2015 and 2019 were followed with preoperative measurements of cephalic index along with postoperative measurements at 6 months to 1 year, respectively. Nineteen patients undergoing cranial vault reconstruction were studied in 2 groups, namely those younger than 6 months who did not have bone grafting performed during primary repair (31.6%) and patients 6 months and older who underwent cranial vault reconstruction with bone grafting during primary repair (68.4%). Mean 6-month to 1-year postoperative cranial index was significantly increased in both groups (P < 0.001). The average cephalic index change for both groups (younger than 6 months without bone grafting, CI value change 9; 6 months and older with bone grafting; CI value change 6) was not significantly different with regards to 95% confidence interval (P = 0.30). Patients older than 6 months of age undergoing cranial vault reconstruction with bone grafting have similar cephalometric outcomes as their younger counterparts undergoing cranial vault remodeling without bone grafting. Bone grafting in the appropriate cohort may improve functional and esthetic outcomes without compromising primary surgical goals of improving cranial vault cephalometric indices.

Long-term 3D CT follow-up after endoscopic sagittal craniosynostosis repair

OBJECTIVE

Surgical treatment of sagittal synostosis involves various surgical modalities. Long-term follow-up issues include increased intracranial pressure, secondary sutural fusion, incomplete reossification, and suboptimal cosmetic appearance. The authors' objective in this study was to review their long-term endoscopic surgical results in children with sagittal synostosis using 3D CT.

METHODS

The authors reviewed the long-term results of their first 38 patients who underwent endoscopic sagittal synostosis repair at age 16 weeks or younger. A standard vertex craniectomy with biparietal wedges was done in each case. After surgery, the children were fitted with a helmet, which they wore until 8 months of age. Patients were followed up for 5 years or longer, at which point a 3D CT scan was obtained. The authors examined data on the cranial index, area of bony defect, presence or absence of secondary sutural fusion, neosuture formation, and scalloping of the inner table of the skull.

RESULTS

Thirty-two of 38 children met inclusion criteria. There was a small but significant recession of the cranial index after the completion of helmeting (from 0.772 after completion of helmeting to 0.755 at 5 years). Of 32 children, 14 had a bony defect area > 4 cm2. Three children had secondary sutural fusion (two unilateral coronal, one bicoronal). Ten of 32 patients had partial neosuture formation.

CONCLUSIONS

The authors report their experience with 32 of their first 38 children who underwent endoscopic sagittal synostosis repair at 16 weeks of age or younger. With a minimum duration of 5 years, this is the longest clinicoradiological follow-up utilizing 3D CT to date in children with sagittal synostosis treated with endoscopic surgery. The authors report detailed measurements of bony loss, adjacent sutural fusion, and neosuture formation.

Long-Term Characterization of Cranial Defects After Surgical Correction for Single-Suture Craniosynostosis

INTRODUCTION

Craniosynostosis is typically corrected surgically within the first year of life through cranial vault reconstruction. These procedures often leave open calvarial defects at the time of surgery, which are anticipated to close over time in a large proportion of cases. However, residual calvarial defects may result as long-term sequelae from cranial vault remodeling. When larger defects are present, they may necessitate further reconstruction for closure.Better understanding of the calvarial osseous healing process may help to identify which defects will resolve or shrink to acceptable size and which will require further surgery. Our study aims to assess the long-term changes in defect size after cranial vault reconstruction for craniosynostosis.

METHODS

One-year postoperative and long-term computed tomography scans were retrieved from the craniofacial anomalies archive. Analysis used custom software. All defects above the size of 1 cm were analyzed and tracked for calvarial location, surface area, and circularity. Monte Carlo simulation was performed to model the effect of initial defect size on the rate of defect closure.

RESULTS

We analyzed a total of 74 defects. The mean ± SD initial defect surface area was 3.27 ± 3.40 cm. The mean ± SD final defect surface area was 1.71 ± 2.54 cm. The mean ± SD percent decrease was 55.06% ± 28.99%. There was a significant difference in the percentage decrease of defects in the parietal and frontoparietal locations: 68.4% and 43.7%, respectively (P = 0.001). Monte Carlo simulation results suggest that less than 10% of defects above the size of 9 cm will close to the size of 2.5 cm or less.

CONCLUSIONS

We describe and make available a novel validated method of measuring cranial defects. We find that the large majority of initial defects greater than 9 cm remain at least 1 in in size (2.5 cm) 1 year postoperatively. In addition, there appear to be regional differences in closure rates across the cranium, with frontoparietal defects closing more slowly than those in the parietal region. This information will aid surgeons in the decision-making process regarding cranioplasty after craniosynostosis correction.

Analysis of clinical outcomes for treatment of sagittal craniosynostosis: a comparison of endoscopic suturectomy and cranial vault remodeling

The authors compared the effectiveness of two main surgical techniques used for treating sagittal craniosynostosis (SC): endoscopic suturectomy (ES) and cranial vault remodeling (CVR). The safety, head growth, and aesthetic results following ES and CVR were compared by reviewing the charts of more than 200 patients. By comparing the effectiveness of these two treatments, this study will help guide selection of the optimal surgical treatment for patients with SC.

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.

Power-Assisted Particulate Bone Grafting Effectively Prevents Osseous Defects After Cranial Vault Reconstruction

BACKGROUND

Cranial vault reconstruction (CVR) is the gold standard in the operative treatment of craniosynostosis. Full thickness osseous defects (FTOD) of the calvaria have been observed in 5% to 15% patients after CVR, with higher rates cited in the fronto-orbital advancement (FOA) subset. Particulate bone graft (PBG) harvested manually has been shown to decrease FTOD after FOA from 24% to 5.5%. The authors used a modified technique using a powered craniotome, with the hypothesis that the technique would also improve outcomes.

METHODS

A retrospective review was performed of patients who underwent CVR for craniosynostosis between 2004 and 2014. Patient demographics, diagnosis, age, operative details, and postoperative care were reviewed in detail. Categorical, nonparametric variables were compared by Fisher exact tests.

RESULTS

A total of 135 patients met inclusion criteria. The most common diagnoses were metopic (n = 41), sagittal (n = 33), and unilateral coronal craniosynostosis (n = 31); 65% (n = 88) underwent FOA, 29% (n = 39) underwent single-stage total vault reconstruction, and 6% (n = 8) had a posterior vault reconstruction. CVR was performed without PBG in 95 patients and with PBG in 40 patients. Without PBG, FTOD were discovered on clinical examination in 18% of patients (n=17): 11 presented with subcentimeter defects, while 6 had larger defects requiring revision cranioplasty (6% operative revision rate). Among those receiving PBG, 1 patient presented a subcentimeter FTOD (2.5% FTOD incidence and 0% operative revision rate).

CONCLUSION

Particulate bone graft harvested with a powered device decreases the rate of FTOD and reoperation rate after CVR for craniosynostosis.

Defining and Correcting Asymmetry in Isolated Unilateral Frontosphenoidal Synostosis: Differences in Orbital Shape, Facial Scoliosis, and Skullbase Twist Compared to Unilateral Coronal Synostosis

INTRODUCTION

Isolated frontosphenoidal synostosis (FS) is a rare cause of fronto-orbital plagiocephaly that can be challenging to distinguish from isolated unicoronal synostosis (UC). The purpose of this paper is to analyze differences in fronto-orbital dysmorphology between the 2 conditions, to describe approaches for surgical correction, and to report surgical outcomes between FS and UC patients in a casecontrol fashion.

METHODS

Patients treated for craniosynostosis over a 12-year period at our institution were retrospectively evaluated under institutional review board approval. Frontosphenoidal synostosis patients who underwent bilateral fronto-orbital correction of anterior plagiocephaly with minimum 2-year follow-up, adequate pre-, and minimum 2-year postoperative computed tomography scans were included in the case-control portion of the study. These patients were randomly age-matched to UC patients meeting the same inclusion criteria. Preoperative and postoperative orbital shape and volumetric analysis was performed using Mimics software.

RESULTS

Twelve FS patients were treated during the study period. Seven of these patients met casecontrol inclusion criteria with average follow-up of 47.5 months. The characteristic FS orbit was a relatively wide, short, and shallow trapezoid, while the characteristic UC orbit was a relatively narrow, tall, and deep parallelogram. Frontosphenoidal synostosis orbits were significantly wider, shorter, shallower, and smaller than UC orbits. Surgical correction tailored to the differential dysmorphologies resulted in statistical equalization of these differences between affected and contralateral control orbits at follow-up, with the exception of UC orbital width, which remained significantly narrower than unaffected contralateral control. One patient in each group required cranioplasty for skull defects at follow-up, while no patient underwent surgical readvancement.

CONCLUSIONS

Frontosphenoidal synostosis and UC orbital shape differ significantly, and can be normalized using fronto-orbital advancement tailored to the distinct orbital dysmorphologies of these 2 groups.

Improved autologous cortical bone harvest and viability with 2Flute otologic burs

OBJECTIVES

To determine if 2Flute (Stryker Corporation, Kalamazoo, MI) otologic burs improve the size, cellular content, and bone healing of autologous cortical bone grafts harvested during canal wall reconstruction (CWR) tympanomastoidectomy with mastoid obliteration.

STUDY DESIGN

Institutional review board-approved prospective cohort study.

METHODS

Human autologous cortical bone chips were harvested using various burs (4 and 6 mm diameter; multiflute, and 2Flute [Stryker Corporation]) from patients undergoing CWR tympanomastoidectomy for the treatment of chronic otitis media with cholesteatoma. Bone chip size, cell counts, cellular gene expression, and new bone formation were quantified.

RESULTS

Bone chips were significantly larger when harvested with 2Flute (Stryker Corporation) bur compared to multiflute burs at both 6 mm diameter (113 ± 14 μm² vs. 66 ± 8 μm² ; P < 0.05) and 4 mm diameter (70 ± 8 μm² vs. 50 ± 3 μm² ; P < 0.05). After 2 weeks in culture, cell numbers were significantly higher when harvested with 2Flute (Stryker Corporation) bur compared to multiflute burs at both 6 mm diameter (48.7 ± 3 vs. 31.8 ± 3 cells/μg bone; P < 0.05) and 4 mm diameter (27.6 ± 1.2 vs. 8.8 ± 1.2 cells/μg bone; P < 0.05). Bone-derived cells express osteoblast markers (alkaline phosphatase, osteocalcin). Cultured cells are able to form new bone in culture, and bone formation is facilitated by the presence of bone chips.

CONCLUSION

Use of 2Flute (Stryker Corporation) otologic burs for human autologous cortical bone harvest results in more viable bone fragments, with larger bone chips and more osteoblasts. Future studies are needed to determine if this leads to improved bone healing.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:E41-E46, 2018.

BMP-7 Preserves Surface Integrity of Degradable-ceramic Cranioplasty in a Göttingen Minipig Model

BACKGROUND

The aim of the study was to evaluate the integrity of a craniotomy grafted site in a minipig model using different highly porous calcium phosphate ceramic scaffolds either loaded or nonloaded with bone morphogenetic protein-7 (BMP-7).

METHODS

Four craniotomies with a diameter of 15 mm (critical-size defect) were grafted with different highly porous (92-94 vol%) calcium phosphate ceramics [hydroxyapatite (HA), tricalcium phosphate (TCP), and biphasic calcium phosphate (BCP; a mixture of HA and TCP)] in 10 Göttingen minipigs: (a) group I (n = 5): HA versus BCP; (b) group II (n = 5): TCP versus BCP. One scaffold of each composition was supplied with 250 μg of BMP-7. In vivo computed tomography scan and fluorochrome bone labeling were performed. Specimens were evaluated 14 weeks after surgery by environmental scanning electron microscopy, fluorescence microscopy, and Giemsa staining histology.

RESULTS

BMP-7 significantly enhanced bone formation in TCP (P = 0.047). Slightly enhanced bone formation was observed in BCP (P = 0.059) but not in HA implants. BMP-7 enhanced ceramic degradation in TCP (P = 0.05) and BCP (P = 0.05) implants but not in HA implants. Surface integrity of grafted site was observed in all BMP-7-loaded implants after successful creeping substitution by the newly formed bone. In 9 of 10 HA implants without BMP-7, partial collapse of the implant site was observed. All TCP implants without BMP-7 collapsed. Fluorescent labeling showed bone formation at week 1 in BMP-7-stimulated implants.

CONCLUSIONS

BMP-7 supports bone formation, ceramic degradation, implant integration, and surface integrity of the grafted site.

Cranioplasty with autogenous bone flaps cryopreserved in povidone iodine: a long-term follow-up study

OBJECTIVE The aim of this study was to investigate the long-term therapeutic efficacy of cranioplasty with autogenous bone flaps cryopreserved in povidone iodine and explore the risk factors for bone resorption. METHODS Clinical data and follow-up results of 188 patients (with 211 bone flaps) who underwent cranioplasty with autogenous bone flaps cryopreserved in povidone-iodine were retrospectively analyzed. Bone flap resorption was classified into 3 types according to CT features, including bone flap thinning (Type I), reduced bone density (Type II), and osteolysis within the flaps (Type III). The extent of bone flap resorption was graded as mild, moderate, or severe. RESULTS Short-term postoperative complications included subcutaneous or extradural seroma collection in 19 flaps (9.0%), epidural hematoma in 16 flaps (7.6%), and infection in 8 flaps (3.8%). Eight patients whose flaps became infected and had to be removed and 2 patients who died within 2 years were excluded from the follow-up analysis. For the remaining 178 patients and 201 flaps, the follow-up duration was 24-122 months (mean 63.1 months). In 93 (46.3%) of these 201 flaps, CT demonstrated bone resorption, which was classified as Type I in 55 flaps (59.1%), Type II in 11 (11.8%), and Type III in 27 (29.0%). The severity of bone resorption was graded as follows: no bone resorption in 108 (53.7%) of 201 flaps, mild resorption in 66 (32.8%), moderate resorption in 15 (7.5%), and severe resorption in 12 (6.0%). The incidence of moderate or severe resorption was higher in Type III than in Type I (p = 0.0008). The grading of bone flap resorption was associated with the locations of bone flaps (p = 0.0210) and fragmentation (flaps broken into 2 or 3 fragments) (p = 0.0009). The incidence of bone flap collapse due to bone resorption was higher in patients who underwent ventriculoperitoneal (VP) shunt implantation than in those who did not (p = 0.0091). CONCLUSIONS Because of the low incidence rates of infection and severe bone resorption, the authors conclude that cranioplasty with autogenous bone flaps cryopreserved in povidone-iodine solution is safe and effective. The changes characteristic of bone flap resorption became visible on CT scans about 2 months after cranioplasty and tended to stabilize at about 18 months postoperatively. The bone resorption of autogenous bone flap may be classified into 3 types. The rates of moderate and severe resorption were much higher in Type III than in Type I. The grade of bone flap resorption was associated with bone flap locations. Fragmented bone flaps or those implanted in patients treated with VP shunts may have a higher incidence of bone flap collapse due to bone resorption.

Anthropometric Outcomes following Fronto-Orbital Advancement for Metopic Synostosis

BACKGROUND

The authors' purpose is to present changes in anthropometric fronto-orbital dimensions after surgical correction of metopic synostosis.

METHODS

The authors retrospectively analyzed craniometric dimensions in older patients with metopic synostosis corrected by fronto-orbital advancement performed by the senior author (J.B.M.). Preoperative and postoperative linear measures (frontal breadth, cranial width, and intercanthal distance) were taken by direct anthropometry. Interdacryon distance and width of the bandeau were also recorded intraoperatively, before and after widening. Follow-up anthropometric values were compared to age- and sex-matched normative data and standard (z) scores were calculated.

RESULTS

Sixteen patients met the inclusion criteria. Syndromic diagnosis was documented in five of 16 patients. Average age at the last postoperative evaluation was 8.9 ± 3.8 years (range, 4 to 16 years). Mean frontal width z-scores decreased postoperatively from 0.82 to -0.32 (p = 0.007), indicating diminished growth in this dimension. The last measured frontal width strongly correlated with the breadth of the bandeau after surgical correction but not with preoperative values. Postoperative mean cranial width diminished significantly to a more normal value. Mean intercanthal distance was normal preoperatively and remained so but was significantly greater in syndromic than in nonsyndromic cases.

CONCLUSIONS

Frontal growth rate is diminished in the coronal plane after fronto-orbital advancement. The authors recommend primary techniques to overcorrect the width of the bandeau and frontal region, including zygomaticosphenoid osteotomies and interpositional cranial bone grafts to advance/widen the lateral orbital rim. Continued evaluation is required to assess whether overcorrection results in normal frontotemporal shape and breadth at skeletal maturity.

Advantages of Calvarial Vault Distraction for the Late Treatment of Cephalocranial Disproportion

PURPOSE

Cephalocranial disproportion is a symptomatic condition related to a volume discrepancy between the calvarial vault and the brain. Traditional expansion techniques are unfavorable in older children due to inadequate dural ossification, lack of bone pliability, and limited future growth potential. The authors review their experience using distraction to close bone defects in this setting.

METHODS

A retrospective analysis was performed of all patients treated using distraction in this setting by a single surgeon. Demographic and outcomes data were collected. The efficacy of ossification of bone defects after expansion by distraction was measured using volume analysis of three-dimensional computed tomography (CT) scans. This required a CT scan at the completion of device activation and a follow-up CT scan 6 months or more beyond activation.

RESULTS

Sixteen patients (17 distractions) met the imaging-based inclusion criteria. The average age at surgery was 3.97 (2.14-6.89) years. The mean initial bone defect volume after asymmetric transverse distraction was 7.26 (5.45-13.73) mL. The mean final defect volume was 2.18 (0.00-5.90) mL with a mean change of 5.08 (1.21-12.79) mL and mean interval time of 27.85 (7.13-56.39) months. This represents a mean percent defect closure of 72.30 (20.38-100.00).

CONCLUSION

Distraction osteogenesis is a very effective tool for treating the older child with cephalocranial disproportion. The ability to ossify the bone defects without a donor site provides a considerable advantage in these patients.

Safety and efficacy of recombinant human bone morphogenetic protein 2 on cranial defect closure in the pediatric population

BACKGROUND

Traditional reconstructive options for cranial defects include autogenous bone graft, bone substitutes, and synthetic materials. The established standard for repairing cranial defects is autogenous bone. However, young children do not have abundant donor sites for bone harvest, which leads to challenges in closing calvarial defects. Synthetic materials are not ideal alternatives because they require subsequent retrieval and are prone to infection. Their long-term effects on growth of the skull are also not well studied. Bone morphogenetic protein 2 (BMP-2), are shown to positively affect closure of cranial defects in animal models. We present a study comparing the efficacy and safety of closure of cranial defect with bone graft augmented with recombinant human BMP-2 (rhBMP-2) and compared with a series of patients treated with bone graft alone.

METHODS

This study is a retrospective multicenter evaluation of 36 patients spanning 5 years. Twenty-one patients undergoing cranial defect closure augmented with rhBMP-2 were compared with 15 patients who underwent cranial defect closure using cranial bone shavings alone. We measured preoperative and postoperative defect size on volumetric computed tomographic scan reconstructions to compare defect sizes.

RESULTS

The rhBMP-2 group had slightly increased proportional closure compared with the control group, 86% versus 76% (P < 0.018), respectively. Two patients in the rhBMP-2 group had postoperative fusion of a suture that was known to be patent at the time of cranial defect closure. No instances of brain edema, herniation, airway compromise, or other adverse effects directly attributable to rhBMP-2 were observed.

CONCLUSIONS

Bone morphogenetic protein 2 may increase the amplitude and uptake of cranial bone grafts in cranial defect closure. This study shows that defect sizes of up to 16 cm can be reliably closed using this technique. Postoperative fusion of uninvolved sutures in 2 patients indicates that rhBMP-2 may have unreported adverse effects; consideration of this finding should be weighed against the benefit of improved closure of calvarial defects.

Exchange hybrid cranioplasty using particulate bone graft and demineralized bone matrix: the best of both worlds

Reconstruction of craniofacial defects in children presents several challenges that are not encountered in the adult population. Autologous bone grafts have long been the criterion standard for repairing these defects. Recently, several new materials and techniques have expanded our arsenal of reconstructive options. In this clinical report, we describe the use of both particulate bone grafting and demineralized bone matrix together to repair craniofacial defects encountered in pediatric patients.

Repair of tegmen defect using cranial particulate bone graft

Bone paté is used to repair cranial bone defects. This material contains bone-dust collected during the high-speed burring of the cranium. Clinical and experimental studies of bone dust, however, have shown that it does not have biological activity and is resorbed. We describe the use of bone paté using particulate bone graft. Particulate graft is harvested with a hand-driven brace and 16mm bit; it is not subjected to thermal injury and its large size resists resorption. Bone paté containing particulate graft is much more likely than bone dust to contain viable osteoblasts capable of producing new bone.

An Experimental Study of Particulate Bone Graft for Secondary Inlay Cranioplasty Over Scarred Dura

BACKGROUND

Inlay cranioplasty in children is challenging because autologous bone is limited. Cranial particulate bone graft effectively closes defects when placed over normal dura. The purpose of this study was to determine if particulate bone graft will ossify when used for secondary cranioplasty over scarred dura.

METHODS

A 17 × 17-mm critical-sized defect was made in the parietal bone of 16 rabbits. Four animals had no implant (group 1). Twelve animals had the defect remade 16 weeks postoperatively, which was managed in 2 ways: group 2 (no implant; n = 6) and group 4 (particulate bone graft; n = 6). Particulate graft was obtained using a brace and bit from the frontal bone. Computed tomography was used to determine the area of ossification and thickness of the healed graft. Eight animals previously managed with particulate bone graft over normal dura were used as an additional control (group 3).

RESULTS

Critical-sized defects filled with particulate bone graft over scarred dura (group 4) exhibited superior healing of the area (83.8%; range, 73.0%-90.6%) compared to control defects over normal dura (group 1: 62.9%; range, 56.5%-73.4%) or scarred dura (group 2: 56.9%; range, 40.0%-68.3%) (P = 0.0004). Particulate bone on scarred dura exhibited less ossified area (P = 0.002), and thinner bone (0.95 mm, range, 0.71-1.32 mm) compared to defects in which graft was placed over normal dura (group 3: area, 99.2%; range, 96.8%-100%; thickness, 1.9 mm, range; 1.1-3.1 mm) (P = 0.04).

CONCLUSIONS

Particulate bone graft ossifies inlay cranial defects over scarred dura although inferior to placement over normal dura. Clinically, particulate bone graft may be used for secondary inlay cranioplasty.

Does the Use of Particulate Bone Graft Increase the Incidence of Postoperative Infection in Surgery for Craniosynostosis?

Objective

The use of particulate bone graft (PBG) has become an accepted technique for filling cranial defects created during cranial vault expansion for craniosynostosis. However, the use of PBG may be a risk factor for postoperative infection. The aim of this study was to compare the rate of postoperative infection in patients who received particulate bone graft (PBG+) with that in patients who did not (PBG–).

Design

An Institutional Review Board–approved, retrospective, cohort study of consecutive patients was performed. Twenty-seven consecutive patients in the PBG– group were compared with 21 consecutive patients in the PBG+ group. The two cohorts were assessed for incidence of surgical-site infection.

Results

Statistical analysis was performed using the Fisher exact probability test. Surgical site infection occurred in none of the PBG– patients (0%) versus one of the PBG+ patients (4.76%). This difference in infection rates between the two cohorts was not statistically significant ( P = .4375).

Conclusions

Although there may be concern that PBG could serve as a facilitative medium for bacterial growth, this study demonstrates no statistically significant increase in infection rates with its use. Particulate bone grafting of cranial defects resulting from cranial vault expansion in craniosynostosis remains a useful and valuable technique.

Experimental Comparison of Cranial Particulate Bone Graft, rhBMP-2, and Split Cranial Bone Graft for Inlay Cranioplasty

Background

Particulate bone graft and recombinant human bone morphogenetic protein-2 (rhBMP-2) are options for inlay cranioplasty in children who have not developed a diploic space. The purpose of this study was to determine whether particulate bone graft or rhBMP-2 has superior efficacy for inlay cranioplasty and to compare these substances to split cranial bone.

Methods

A 17 mm × 17 mm critical-sized defect was made in the parietal bones of 22 rabbits and managed in four ways: Group I (no implant; n=5), Group II (particulate bone graft; n=5), Group III (rhBMP-2; n=7), and Group IV (split cranial bone graft; n=5). Animals underwent microcomputed tomography and histologic analysis 16 weeks after cranioplasty.

Results

Defects without an implant (Group I) demonstrated inferior ossification (41.4%; interquartile range [IQR], 28.9% to 42.5%) compared to those treated with particulate bone graft (Group II: 99.5%; IQR, 97.8% to 100%), rhBMP-2 (Group III: 99.6%; IQR, 99.5% to 100%), or split cranial bone (Group IV: 100%) ( P < .0001). There was no difference between Groups II, III, and IV ( P = .1). Defects treated with rhBMP-2 exhibited thinner bone (0.90 mm; IQR, 0.64 to 0.98) than particulate bone graft (1.95 mm; IQR, 1.09 to 2.83) or split cranial bone (1.72 mm; IQR, 1.54 to 1.88) ( P = .006); particulate and split cranial bone grafted defects had a similar thicknesses ( P = .6).

Conclusions

Particulate bone graft, rhBMP-2, and split cranial bone close inlay calvarial defect areas equally, although the thickness of bone healed with rhBMP-2 is inferior. Clinically, particulate bone graft or split cranial bone graft may be superior to rhBMP-2 for inlay cranioplasty.

The microsurgical treatment of cranio-orbital tumors assisted by intraoperative electrophysiologic monitoring and neuronavigation

OBJECTIVE

Total resection of cranio-orbital tumors without any major complications is still a challenge for neurosurgeons. Intraoperative electrophysiologic monitoring and neuronavigational system have been widely used in microneurosurgery, but their effects during microsurgical treatment of cranio-orbital tumors warrant further investigation.

METHODS

Thirty-eight patients with cranio-orbital tumors admitted to our hospital underwent microsurgery assisted by intraoperative electrophysiologic monitoring. We also simultaneously performed intraoperative neuronavigation in 20 patients. A retrospective review of clinical notes, operation records and prognoses of all patients was performed.

RESULTS

Gross total resection was achieved in 29 patients (76%), near total resection in 5 (13%), subtotal resection in 3 (8%) and partial resection in 1 (3%). With the helps of electromyogram (EMG) monitoring of levator palpebrae superioris (LPS) muscle and navigation system, no surgical damages to the oculomotor nerve and other important structures occurred. A follow-up study showed that 31 patients (82%) resumed normal lives (Glasgow Outcome Scale (GOS) score 5), 5 patients (13%) had independent lives (GOS score 4), and 2 patients (5%) were unable to live independently (GOS score 3).

CONCLUSION

Microsurgical treatment assisted by intraoperative electrophysiologic monitoring and neuronavigation might be a useful method for resection of cranio-orbital tumors, especially better for protection of the important cranial nerve and structure in the kull base.

Spectrum of primary bone grafting in cranio maxillofacial trauma at a tertiary care centre in India

Background:

In past several years, traumas following road traffic accidents and other causes have increased, owing to an increase in mechanization and pace of life. These patients frequently have complicated injuries involving soft tissue and the craniofacial skeleton. Assessment of bony injuries and loss of portions of facial skeleton and their management has proved to be a challenge to the reconstructive surgeon.

Aims:

Primary bone grafting of craniofacial skeletal injuries provides an opportunity for one stage correction of bony defects. The varied spectrum of primary bone grafts for management of craniomaxillofacial injuries are evaluated in this study.

Materials and Methods:

Patients with a history of acute trauma resulting in facial skeletal injuries with or without bone loss were included in the study. Primary bone grafting was undertaken in situations requiring contour correction, replacement of skeletal losses and for rigid fixation of fracture segments. Olecranon, Iliac crest, ribs, Vascularized as well as nonvascularized outer table calvarial grafts and nonvascularized inner table calvarial grafts were used in this study.

Results:

Sixty two patients of craniomaxillofacial injury following trauma requiring primary bone grafting were considered in this study. Fifty seven percent of patients (n=32) required primary bone grafting for replacement of bone loss while bone grafting for contour correction was done in twenty three patients. The parietal calvaria overlying the non-dominant hemisphere was used as a source of bone graft in forty-nine patients. Nearly ninety-two percent of the patients were satisfied with the results of primary bone grafting.

Conclusions:

Functional and aesthetic assessment of each of these patients, managed with primary bone grafting revealed a low rate of disabilities and high percentage of satisfaction in this study.

Autologous cranial particulate bone graft: an experimental study of onlay cranioplasty

The purpose of this study was to determine whether particulate bone graft maintains its volume when used for onlay cranioplasty. Twenty-five adult, male, New Zealand white rabbits were divided into 5 groups (n = 5/group). Groups 1 to 3 were controls: group 1, untreated; group 2, sham procedure; and group 3, burring the cortical surface. Group s 4 and 5 had augmentation of the parietal bones with particulate graft harvested from the frontal bone with a brace and bit. The particulate graft was placed on native parietal bone (group 4) or on parietal bone that had been abraded to punctuate bleeding with an electric burr (group 5). Volume maintenance and osseointegration of the grafts were determined by micro-computed tomography and histology. At 16 weeks postoperatively, the mean (SD) volumes of the parietal bones in control groups 1, 2, and 3 were 555.8 (29.2), 550.8 (36.8), and 539.0 (39.0) mm, respectively. Immediately after cranioplasty, the mean (SD) volumes of augmented parietal bone were 846.0 (10.8) mm for group 4 and 831.8 (11.8) mm for group 5. Sixteen weeks postoperatively, 100% of the group 4 grafts had resorbed (551.8 [SD, 24.0] mm), and parietal volume was no different from controls (P = 0.89). Group 5 maintained 54.2% of volume (695.6 [SD, 22.0] mm), which was greater than those of the controls (P < 0.0001). Particulate graft may be used for onlay cranioplasty if the recipient site is burred. Approximately one half of the onlay graft is resorbed, and its original shape is not maintained.

Exchange cranioplasty using autologous calvarial particulate bone graft effectively repairs large cranial defects

BACKGROUND

Autogenous particulate cranial bone graft has been proven to be effective for inlay cranioplasty but does not provide structural contour. This limitation can be overcome using an exchange cranioplasty technique. This study probes the effectiveness of this method for large (>5 cm(2)) or complicated cranial defects.

METHODS

The authors conducted a retrospective review of patients managed with autologous exchange cranioplasty between 2005 and 2010. Full-thickness calvarial bone was removed from the intact cranium; particulate bone graft was harvested from the graft endocortex or ectocortex of intact cranium. The original defect was repaired with the full-thickness graft and the donor site was covered with particulate graft. Patient records were reviewed for age at cranioplasty, operative indication, size and location of defect, operative time, blood loss, and length of follow-up. Outcome variables included complications, osseous defects, and need for revision cranioplasty.

RESULTS

Twenty patients underwent exchange cranioplasty at a mean age of 8.3 ± 6.2 years. Average values for the group included length of procedure, 4.7 hours; estimated blood loss, 288 ml; hospital stay, 3.1 days; and follow-up, 1.57 years (range, 24 weeks to 3.7 years). Eighty-five percent of patients underwent postoperative computed tomographic scanning to document healing. Fifteen patients had complete healing; five patients had residual bone defects (four by computed tomography and palpation, and one by computed tomography only). The cranial defect area decreased 96 percent on average from a preoperative mean of 85.2 cm(2) to a postoperative combined defect size (donor plus recipient) of 3.3 cm(2).

CONCLUSION

Autologous exchange cranioplasty using particulate bone graft is safe and highly effective for reconstructing even large cranial defects.

A rare case of psammomatoid ossifying fibroma in the sphenoid bone reconstructed using autologous particulate exchange cranioplasty

Psammomatoid ossifying fibroma (POF), a variant of ossifying fibroma, is a benign fibroosseous lesion typically arising within the nasal cavity, paranasal sinuses, and orbit. Cranial vault involvement is exceedingly rare, with very few cases reported in the literature. The authors report a case of POF in the neurocranium of an 11-year-old child, 4 years after chemotherapy and radiation therapy for acute lymphoblastic leukemia. This case is reported in view of its rarity, novelty of presentation, and the difficulty in diagnosis due to its radiological resemblance to aneurysmal bone cyst or monostotic cystic fibrous dysplasia, further aggravated by the clinical scenario. A novel technique of cranial reconstruction called autologous particulate exchange cranioplasty was used following tumor excision.

Repair of a large congenital frontal bone defect with autologous exchange cranioplasty

The authors report the case of a large idiopathic frontal bone defect and concomitant sagittal synostosis corrected by autologous exchange cranioplasty by using a corticocancellous bone graft and cranial vault expansion. An otherwise healthy, developmentally normal 6-year-old girl presented to our clinic with a large frontal bone defect. The osseous defect was midline and inferior to the coronal sutures, and the underlying dura was slightly tense. She had no signs or symptoms of increased intracranial pressure, and her head circumference and cephalic index were normal. Imaging demonstrated fusion of the sagittal synostosis. The defect was repaired using full-thickness autologous bone harvested from the bilateral parietal regions, which were widened using barrel-stave osteotomies to reduce pressure on the graft site in the setting of sagittal synostosis and mild cranial narrowing. The donor sites were covered with autologous particulate bone graft harvested from the endocortical surface of the grafted segments and the ectocortical surface of the intact parietal bones. The donor and recipient sites healed. Imaging revealed that the particulate bone healed with a thickness similar to the surrounding bone. This bony defect is analogous to parietal foramina and may have a similar etiopathogenesis. The technique of autologous exchange cranioplasty using corticocancellous particulate bone graft provides a simple and reliable method to repair large structural calvarial defects.

Treatment of unilateral coronal synostosis by endoscopic strip craniectomy or fronto-orbital advancement: Ophthalmologic findings

BACKGROUND

Unilateral coronal synostosis results in ipsilateral retrusion of the forehead and superior orbital rim, shortening the elevation of the orbital roof and contralateral frontal bossing and orbital roof depression. This craniosynostosis is associated with the development of V-pattern strabismus and aniso-astigmatism. Since 2004 endoscopic strip craniectomy performed in patients by 3 months of age has been offered as an alternative to fronto-orbital advancement at 9 to 11 months of age. We compare the incidence and severity of V-pattern strabismus and aniso-astigmatism in children treated by these 2 procedures.

METHODS

A retrospective review identified 37 children with unilateral coronal synostosis treated with either fronto-orbital advancement or endoscopic strip craniectomy. Incidence and severity of V-pattern strabismus, fundus excyclotorsion, and aniso-astigmatism was recorded for an "early" examination (between 2 and 14 months of age) and a "late" examination (between 14 and 45 months of age).

RESULTS

Early examination revealed no statistical difference in severity of V-pattern strabismus or aniso-astigmatism between the 2 groups. At late examination there was a trend toward greater severity of V-pattern strabismus, an increase in excyclotorsion, and a statistically significant increase in the standard deviation of aniso-astigmatism in the cohort of children treated by fronto-orbital advancement.

CONCLUSIONS

Children with unilateral coronal synostosis treated by early endoscopic strip craniectomy may develop less severe V-pattern strabismus, excyclotorsion, and range of aniso-astigmatism than those treated by later fronto-orbital advancement. This is an early, retrospective, nonrandomized study with a short follow-up period; longer follow-up is necessary to confirm these results.

Global age-dependent differences in gene expression in response to calvarial injury

Children less than 2 years of age are capable of healing large calvarial defects, whereas adults have been found to lack this endogenous ability. In this study, we used microarray analysis to compare genomewide expression patterns during active regeneration after injury with calvaria in skeletally immature and mature mice. Parietal bone defects were created in 6-day-old (juvenile) and 60-day-old (adult) mice using a 4-mm trephine bit (n = 20 mice per age group). The calvarial disc was removed, leaving the underlying dura mater intact. Two weeks after injury, the region of regeneration with the underlying dura mater was harvested, and RNA was extracted for microarray analysis. The 25 most differentially upregulated genes in juvenile regenerates compared with adults were listed, as well as selected bone-related genes. In addition, QRT-PCR confirmation of specific genes was performed for validation. Juvenile regenerates expressed significantly greater amounts of BMP-2, -4, -7, as well as FGF-2 and its receptor FGFR-1. Various other growth factors were also noted to be upregulated, including IGF-2 and Ptn. This corresponded with the increased expression of markers for osteogenic differentiation of Sparc and Oc. Markers of osteoclast activity, Acp5, Ctsk, and Mmp2, were noted to be greater in juvenile regenerates compared with adults. The observation of Mmp14 upregulation, however, highlights the importance of balanced osteoclast-mediated bone resorption for ultimate healing. The 2 most differentially regulated genes, transthyretin (Ttr) and prostaglandin D2 synthase (Ptgds), highlight the potential role of retinoic acid signaling and the prostaglandin axis on skeletal regeneration. These findings underscore the multitude of biomolecular mechanisms at play, allowing juvenile calvaria to heal after injury. The identification of various growth factors and cytokines involved also suggests novel therapeutic strategies for tissue-engineering purposes.