Autologous Cranial Particulate Bone Grafting Reduces the Frequency of Osseous Defects After Cranial Expansion

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.

Three-Dimensional Analysis and Surgical Planning for Open Correction of Trigonocephaly

SUMMARY

Metopic craniosynostosis results in trigonocephaly, characterized by a triangular forehead with metopic ridge, bitemporal pinching, and narrow-set eyes with recessed lateral orbital rims. Surgical management is controversial but may include open expansion and vault remodeling, to enhance neurocognitive and aesthetic outcomes. This article and video vignette depict the diagnosis and treatment of metopic craniosynostosis, demonstrating the senior author's open approach, three-dimensional virtual surgical planning, and technical steps.

Low-Cost Customized Cranioplasty with Polymethyl Methacrylate Using 3D Printer Generated Mold: An Institutional Experience and Review of Literature

Background Cranioplasty is performed to repair skull defects and to restore normal skull anatomy. Optimal reconstruction remains a topic of debate. Autologous bone flap is the standard option but it may not be available due to traumatic bone fractures, bone infection, and resorption. In this article, the authors presented their experience with prefabrication of precise and low-cost polymethyl methacrylate (PMMA) mold using three-dimensional (3D) digital printing.

Materials and Methods A total of 30 patients underwent cranioplasty between March 2017 and September 2019 at Sawai Man Singh Medical College Jaipur, India. Preoperative data included diagnosis for which decompressive craniectomy was done and Glasgow coma scale score. Intraoperative data included operating time. Postoperative data included cosmetic outcome in the form of cranial contour and margins, complications such as infection, seroma, implant failure, wound dehiscence, and hematoma.

Results Patient age at cranioplasty ranged from 12 to 63 years with a mean age of 36.7 years. The mean operating time was 151.6 minutes (range 130–190 minutes). The mean follow-up period was 8 months (range 6–13 months). Postoperative wound dehiscence developed in one case (3.3%). Cranial contour and approximation of the margins were excellent and aesthetic appearance improved in all patients.

Conclusion Low-cost PMMA implant made by digital 3D printer mold is associated with reconstruction of the deformed skull contour giving satisfactory results to the patient and his family members, at a low cost compared with other commercially available implants. This technique could be a breakthrough in cranioplasty.

Autologous Calvarial Bone Remodeling Technique for Small to Medium-Sized Cranial Defects in Young Children: The "Switch-Cranioplasty" Technique

INTRODUCTION

Reconstruction of cranial defects in children less than 2 years of age, particularly when there is an associated dural defect, is challenging due to the need to accommodate active skull growth, limited options for autologous bone graft and thin calvarial bones. We use a simple remodeling technique that exploits the normal dura's inherent potential for new bone growth while covering the dural defect with adjacent skull.

CASE PRESENTATION

We describe an alternating, two-piece craniotomy or "switch-cranioplasty technique" to repair an occipital meningocele. The two pieces of craniotomy bone flap created around the existing skull and dural defect are switched in the horizontal plane in order to cover the site of the defect and the abnormal dura of the meningocele closure. The area of the original skull defect is transposed laterally over the normal dura. The healing of the lateral skull defects is facilitated with autologous bone chips and dust and covered by periosteal flaps that stimulate spontaneous re-ossification.

DISCUSSION

The advantages of this technique are the use of autologous bone adjacent to the skull defect, incorporation of the autologous bone into the growing skull, an acceptable cosmetic and functional outcome in a simple manner. The indications can be extended to include small to medium-sized calvarial defects secondary to leptomeningeal cyst and trauma.

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.

Alloplastic Cranioplasty Reconstruction: A Systematic Review Comparing Outcomes With Titanium Mesh, Polymethyl Methacrylate, Polyether Ether Ketone, and Norian Implants in 3591 Adult Patients

BACKGROUND

Acquired defects of the cranium represent a reconstructive challenge in patients with calvarial bone loss due to trauma, infection, neoplasia, congenital malformations, or other etiologies. The objective of this study was to compare postoperative rates of infection, local complications, and allograft failures following cranioplasty reconstruction using titanium mesh (Ti), polymethyl methacrylate (PMMA), polyether ether ketone (PEEK), and Norian implants in adult patients.

METHODS

This constitutes the first systematic review of available literature on 4 different methods of alloplastic cranioplasty reconstruction, including Ti, PMMA, PEEK, and Norian implants, using the Newcastle-Ottawa Quality Assessment Scale guidelines for article identification, screening, eligibility, and inclusion. Electronic literature search included Ovid MEDLINE/PubMed, EMBASE, Scopus, Google Scholar, and Cochrane Database. Pearson exact test was utilized at P < 0.05 level of significance (J.M.P. v11 Statistical Software).

RESULTS

A total of 53 studies and 3591 patients (mean age, 40.1 years) were included (Ti = 1429, PMMA = 1459, PEEK = 221, Norian = 482). Polymethyl methacrylate implants were associated with a significantly higher infection rate (7.95%, P = 0.0266) compared with all other implant types (6.05%). Polyether ether ketone implants were associated with a significantly higher local complication rate (17.19%, P = 0.0307, compared with 12.23% in all others) and the highest ultimate graft failure rate (8.60%, P = 0.0450) compared with all other implant types (5.52%).

CONCLUSIONS

This study qualifies as a preliminary analysis addressing the knowledge gap in rates of infection, local surgical complication, and graft failure in alloplastic cranioplasty reconstruction with different implant types in the adult population. Longer-term randomized trials are warranted to validate associations found in this study.

Low-Cost Customized Cranioplasty with Polymethyl Methacrylate Using 3D Printer Generated Mold: An Institutional Experience and Review of Literature

Background Cranioplasty is performed to repair skull defects and to restore normal skull anatomy. Optimal reconstruction remains a topic of debate. Autologous bone flap is the standard option but it may not be available due to traumatic bone fractures, bone infection, and resorption. The authors present their experience with prefabrication of precise and low-cost polymethyl methacrylate (PMMA) mold using three-dimensional (3D) digital printing.

Methods A total of 30 patients underwent cranioplasty between March 2017 and September 2019 at Sawai Man Singh Medical College Jaipur, India. Preoperative data included diagnosis for which decompressive craniectomy was done and Glasgow coma scale score was observed. Intraoperative data included operating time. Postoperative data included cosmetic outcome in the form of cranial contour and margins, complications such as infection, seroma, implant failure, wound dehiscence, and hematoma.

Results Patient age at cranioplasty ranged from 12 to 63 years with a mean age of 36.7 years. The mean operating time was 151.6 minutes (range 130–190 minutes). The mean follow-up period was 8 months (range 6–13 months). Postoperative wound dehiscence developed in one case (3.3%). Cranial contour and approximation of the margins were excellent and aesthetic appearance improved in all patients.

Conclusion Low-cost PMMA implant made by digital 3D printer mold is associated with reconstruction of the deformed skull contour giving satisfactory results to the patient and his family members, at a low cost compared with other commercially available implants. This technique could be a breakthrough in cranioplasty.

Demineralized Bone Matrix and Resorbable Mesh Bilaminate Cranioplasty Is Ineffective for Secondary Reconstruction of Large Pediatric Cranial Defects

Replacement of the autologous bone flap after decompressive craniectomy can be complicated by significant osteolysis or infection with large defects over scarred dura. Demineralized bone matrix is an alternative to autologous reconstruction, effective when reconstructing large defects using a resorbable mesh bilaminate technique in primary cranioplasty, but this technique has not been studied for revision cranioplasty and the setting of scarred dura. Retrospective review was performed of patients receiving demineralized bone matrix and resorbable mesh bilaminate cranioplasty for postdecompressive craniectomy defects. Seven patients (mean age, 4.2 years) were identified with a mean follow-up of 4.0 years. Computed tomography before the demineralized bone matrix and resorbable mesh bilaminate cranioplasty and at least 1 year postoperatively were compared. Defects were characterized and need for revision was assessed. All patients had craniectomy with associated hemidural scarring. Five patients had autologous bone flap cranioplasty associated with nearly total osteolysis, and two patients had deferral of bone flap before demineralized bone matrix and resorbable mesh bilaminate cranioplasty. Demineralized bone matrix and resorbable mesh bilaminate cranioplasty demonstrated unpredictable and poor ossification, with bony coverage unchanged at postoperative follow-up. All patients required major revision cranioplasty at a mean time of 2.5 years. Porous polyethylene was successfully used in six of the revisions, whereas exchange cranioplasty was used in the remaining patient, with a mean follow-up of 1.4 years. Although demineralized bone matrix and resorbable mesh bilaminate is appropriate for primary cranioplasty, it should be avoided in the setting of scarred or infected dura in favor of synthetic materials or exchange cranioplasty. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.

The Use of Finite Element Method Analysis for Modeling Different Osteotomy Patterns and Biomechanical Analysis of Craniosynostosis Correction

PURPOSE

Several post-processing algorithms for 3D visualization of the skull in craniosynostosis with their specific advantages and disadvantages have been already described. The Finite Element Method (FEM) described herein can also be used to evaluate the efficacy of the cutting patterns with respect to an increase in the projected surface area under assumed uniform loading of the manipulated and cut bone segments.

METHODS

The FEM analysis was performed. Starting with the classic cranial osteotomies for bifrontal craniotomy and orbital bandeau a virtually mirroring of the unaffected triangular shaped frontal bone was performed to achieve a cup-shaped sphere of constant thickness of 2.5 mm with a radius of 65 mm. Mechanical properties required for the analysis were Young's modulus of 340 MPa and Poisson's ratio of 0.22. Four different cutting patterns from straight to curved geometries have been projected onto the inner surface of the sphere with a cutting depth set to 2/3rds of the shell thickness. The necessary force for the deformation, the resulting tensions and the volume loss due to the osteotomy pattern were measured.

RESULTS

Better outcomes were realized with pattern D. The necessary force was 73.6% smaller than the control group with 66N. Best stress distribution was achieved. Curved cutting patterns led to the highest peak of stress and thus to a higher risk of fracture. Straight bone cuts parallel to the corners or to the thighs of the sphere provided a better distribution of stresses with a small area with high stress. Additionally, also with pattern D a surface increase of 20.7% higher than reference was registered.

CONCLUSION

As a proof of concept for different cutting geometries for skull molding in the correction of craniosynostosis, this computational model shows that depending of the cutting pattern different biomechanical behavior is achieved.

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.

Multiple Delayed Scalp Reconstruction for Complicated Cranial Defects

In cases of skull trauma, emergency surgery for cranial decompression typically involves the shortest approach, with the incision lying directly on or immediately near the bony defect. Subsequent reconstructive plastic surgery for the skull is difficult in such cases because incisions taken on the previous scar overlying the bony defect are prone to dehiscence and infection. Herein, we describe a technique for creating a well-vascularized delayed skin flap via multistaged operation before the actual skull reconstruction. Four patients (age range, 10-25 y) were prepared for skull reconstruction using this technique. Flap elevation was performed in 3 stages, with adequate time intervals (4 wk between each stage) to allow for adequate delay. Dissection under the galea aponeurotica was performed only after initial flap elevation allowing for adequate vascularization. Skull reconstruction was then performed using custom-made implants. The patients were followed up for 6 to 12 months. No complications, including infections, exposure of the artificial bone, or flap necrosis, were observed. All the patients were satisfied with the cosmetic results. Despite the multiple stages required, we consider that our technique of using a delayed, well-vascularized bipedicled skin flap can be successfully used in the skull reconstruction of patients in whom the initial scar lies close to the bone defect. We recommend scalp incision be shifted outside of the foreseen bony flap to limit infectious risks during primary or subsequent cranial reconstruction.

Surgical results of cranioplasty with a polymethylmethacrylate customized cranial implant in pediatric patients: a single-center experience

OBJECTIVE Cranioplasty is a reconstructive procedure used to restore skull anatomy and repair skull defects. Optimal skull reconstruction is a challenge for neurosurgeons, and the strategy used to achieve the best result remains a topic of debate, especially in pediatric patients for whom the continuing skull growth makes the choice of material more difficult. When the native bone flap, which is universally accepted as the preferred option in pediatric patients, is unavailable, the authors' choice of prosthetic material is a polymethylmethacrylate (PMMA) implant designed using a custom-made technique. In this paper the authors present the results of their clinical series of 12 custom-made PMMA implants in pediatric patients. METHODS A retrospective study of the patients who had undergone cranioplasty at Gaslini Children's Hospital between 2006 and 2013 was conducted. A total of 12 consecutive cranioplasties in 12 patients was reviewed, in which a patient-specific PMMA implant was manufactured using a virtual 3D model and then transformed into a physical model using selective laser sintering or 3D printing. All patients or parents were administered a questionnaire to assess how the patient/parent judged the aesthetic result. RESULTS Patient age at craniectomy ranged from 5 months to 12.5 years, with a mean age of 84.33 months at cranioplasty. The mean extension of the custom-made plastic was 56.83 cm(2). The mean time between craniectomy and cranioplasty was 9.25 months. The mean follow-up duration was 55.7 months. No major complications were recorded; 3 patients experienced minor/moderate complications (prosthesis dislocation, granuloma formation, and fluid collection). CONCLUSIONS In this patient series, PMMA resulted in an extremely low complication rate and the custom-made technique was associated with an excellent grade of patient or parent satisfaction on long-term follow up.

Resorbable Construct for Subtotal Cranial Vault Remodeling

INTRODUCTION

Pansynostosis can result in markedly thin calvarial bone resulting in poor quality and quantity of allograft for cranial vault expansion. Such scenarios can result in large calvarial defects and poorly stabilized constructs. Additionally, the osteoinductive properties of neonatal dura and paracranium in cranial vault reconstruction suggest the possibility of reconstructing extensive calvarial defects using minimal native calvarium given the appropriate scaffold. We report a case of subtotal cranial vault remodeling involving greater than 50% of the cranial vault using a custom poly DL lactic acid (Sonic Weld) resorbable plate construct and underlay calvarial bone grafting.

METHODS

A 4-month-old male infant presented with a diagnosis of Cruzon syndrome and pansynostosis. Staged reconstruction was performed with the initial stage involving the posterior and middle cranial vault. Given the severity of the deformity, the native cranial bone was thinned with multiple defects such that it could not be used to provide structural integrity or sufficient surface coverage for cranial vault reconstruction. Useable bone comprised only a fraction of the surface area required to expand the posterior and midcranium. Resorbable poly DL lactic acid (Sonic Weld) plates were used to create a custom construct for reconstruction of the posterior and middle cranial vault. The construct was then seeded with usable fragments of the native calvarium and secured to the cranial base with resorbable pins.

RESULTS

The construct resulted in maintained cranial shape throughout the postoperative period. Postoperative computed tomography imaging demonstrated osteogenesis throughout the construct with bridging of the fragmented calvarial grafts. Examination of the construct during anterior cranial vault remodeling demonstrated near complete resorption of the construct, stable posterior cranial vault, and minimal dural adhesions to the posterior cranium. At 11 months postoperatively, the patient continues to demonstrate appropriate cranial expansion and maintenance of posterior cranial shape.

CONCLUSIONS

Fully resorbable constructs can provide effective structural support and a scaffold for osteogenisis in conjunction with minimal native calvarial bone grafts during reconstruction of large cranial vault defects in the infantile period.

Armadillo cranioplasty for expansion and remodeling in craniosynostosis

Craniosynostosis is typically treated in the first year of life, when osteogenic potential is high and residual obligate skull defects heal. Delayed reconstruction can result in persistent skull defects because of diminished osteogenic potential. Adequately expanding the cranium yet minimizing residual skull defects in older patients presents a conundrum. Although secondary cranioplasty can be performed, primary cortical bone coverage is preferred. The authors present a technique of cranial expansion by sliding stairstep osteotomies, thus preventing residual skull defects when treating craniosynostosis at an advanced age.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

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.

Clinical outcomes in cranioplasty: risk factors and choice of reconstructive material

BACKGROUND

Continuing advances in cranioplasty have enabled repair of increasingly complicated cranial defects. However, the optimal materials and approaches for particular clinical scenarios remain unclear. This study examines outcomes following cranioplasty for a variety of indications in patients treated with alloplastic material, autogenous tissue, or a combination of both.

METHODS THE AUTHORS CONDUCTED

a retrospective analysis on 180 patients who had 195 cranioplasties performed between 1993 and 2010.

RESULTS

Materials used for cranioplasty included alloplastic for 42.6 percent (83 of 195), autologous for 19.0 percent (37 of 195), and both combined for 38.5 percent (75 of 195). Mean defect size was 70.5 cm. A subset of patients had undergone previous irradiation (12.2 percent; 22 of 180) or had preoperative infections (30.6 percent; 55 of 180). The most common complication was postoperative infection (15.9 percent; 31 of 195). Factors that significantly predisposed to complications included preoperative radiation, previous infection, and frontal location. Preoperative radiation was the strongest predictor of having any postoperative complications, with an adjusted odds ratio of 6.91 (p < 0.005). Irradiated patients (OR, 7.96; p < 0.05) and patients undergoing frontal cranioplasties (OR, 2.83; p < 0.05) were more likely to require repeated operation. Preoperative infection predisposed patients to exposure of hardware in alloplastic reconstructions (OR, 3.13; p < 0.05).

CONCLUSIONS

Despite the evolution of cranioplasty techniques and materials, complications are not uncommon. The choice of reconstructive material may modify the risk of developing postoperative complications but appears less important than the clinical history in affecting outcome.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

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.

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.