Long-Term Follow-Up Experience with Carbonated Calcium Phosphate Cement (Norian) for Cranioplasty in Children and Adults:

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Biopsies from the Distal Radius after Implantation of Calcium Phosphate Cement

Background: Calcium Phosphate (CaP) bone cement is gradually replaced by new bone when used as a gap-filler. Details of the re-modelling process are still unclear. Uncertainty is also present as to the possible release of cement particles during the resorption phase causing local soft tissue reactions. The objective of this study was to perform a comprehensive histological investigation of the injectable CaP bone cement used as a void filler in corrective radius osteotomies and adjacent tissue reactions.

Methods: Fourteen patients, median age 56 years (18–72), 4 men/10 women, underwent removal of distal radius plates (11 dorsal/3 volar) due to tenosynovitis-like symptoms. Eleven study patients went through corrective osteotomies with CaP bone cement and three were control patients. Previous surgery in three controls consisted in (1) corrective osteotomy with bone graft (dorsal plate), and (2) plated distal radius fractures (1 dorsal/1 volar plate). Biopsies were taken of bone-cement-bone junctions (11), bone-bone graft-bone junctions (1), bone (2) and juxtaposing soft tissue (14). The interval from corrective CaP cement surgery to biopsy was median 1.1 (0.6–2.3) years.

Results: Biopsies of bone-cement junctions showed the different stages of new bone formation from CaP to immature bone and later mature well-organised bone. The cement showed signs of osteoclast-mediated resorption. Cement particles, macrophages, multinucleated giant cells (MNGC) and plasma cells were observed in most soft tissue biopsies. MNGC with internalised particles were seen. Macrophages were found along and/or within tendon sheaths in all patients in both groups, but rarely containing cement particles.

Conclusions: Gradual re-modelling of the cement into well-organised bone was observed confirming osteoclast–osteoblast coupling. There was no indication that cement particles were the cause of the tenosynovitis-like symptoms.

Calcium phosphate bone cement and metaphyseal -corrective osteotomies in the upper extremity: long-term follow-up of 10 children

BACKGROUND AND PURPOSE

The evaluation of metaphyseal angular deformities in children includes indication and timing for corrective osteotomy, and possible need for several operations during growth. Gap-fillers are usually autologous bone grafts, which might cause donor site problems. Calcium phosphate (CaP) bone cement may be a possible alternative.

PATIENTS AND METHODS

We performed 15 corrective osteotomies from 2007 to 2013 in 10 children, ages 5 to 18, with Norian SRS bone cement as a gap-filler, in the distal radius (12), proximal radius (1), and proximal humerus (2). Due to growth arrest and gradually increasing malalignments 3/10 children needed 1-3 additional corrections. Locking plates and screws were used except in 1 case at first surgery, aged 5 (K-wires). 2 children needed additional limb lengthening with external fixator.

RESULTS

All osteotomies healed. Postoperative radiographs and CT scans showed good alignment and gradual transformation of cement into bone. Remodeling was visible intraoperatively in patients needing multiple surgeries. Return to earlier osteotomy sites was unproblematic. No adverse events from using CaP cement were experienced.

INTERPRETATION

CaP cement is an alternative to bone grafts in upper extremity metaphyseal corrective osteotomies in children, and also when greater corrections are necessary or several surgeries indicated during the growth period.

Skeletal regeneration for segmental bone loss: Vascularised grafts, analogues and surrogates

Massive segmental bone defects (SBD) are mostly treated by removing the fibula and transplanting it complete with blood supply. While revolutionary 50 years ago, this remains the standard treatment. This review considers different strategies to repair SBD and emerging potential replacements for this highly invasive procedure. Prior to the technical breakthrough of microsurgery, researchers in the 1960s and 1970s had begun to make considerable progress in developing non autologous routes to repairing SBD. While the breaktthrough of vascularised bone transplantation solved the immediate problem of a lack of reliable repair strategies, much of their prior work is still relevant today. We challenge the assumption that mimicry is necessary or likely to be successful and instead point to the utility of quite crude (from a materials technology perspective), approaches. Together there are quite compelling indications that the body can regenerate entire bone segments with few or no exogenous factors. This is important, as there is a limit to how expensive a bone repair can be and still be widely available to all patients since cost restraints within healthcare systems are not likely to diminish in the near future. STATEMENT OF SIGNIFICANCE: This review is significant because it is a multidisciplinary view of several surgeons and scientists as to what is driving improvement in segmental bone defect repair, why many approaches to date have not succeeded and why some quite basic approaches can be as effective as they are. While there are many reviews of the literature of grafting and bone repair the relative lack of substantial improvement and slow rate of progress in clinical translation is often overlooked and we seek to challenge the reader to consider the issue more broadly.

Cranioplasty

Calvarial defects are commonly encountered after neurosurgical procedures, trauma, and ablative procedures of advanced head neck cancers. The goals of cranioplasty are to provide a protective barrier for the intracranial contents, to restore form, and prevent syndrome of the trephined. Autologous and alloplastic techniques are available, each with their advantages and drawbacks. A multitude of materials are available for cranioplasty, and proper timing of reconstruction with attention to the overlying skin envelope is important in minimizing complications.

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

ABSTRACT

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

Complications of cranioplasty in relationship to traumatic brain injury: a systematic review and meta-analysis

Despite being a common procedure, cranioplasty (CP) is associated with a variety of serious, at times lethal, complications. This study explored the relationship between the initial injury leading to decompressive craniectomy (DC) and the rates and types of complications after subsequent CP. It specifically compared between traumatic brain injury (TBI) patients and patients undergoing CP after DC for other indications.A comprehensive search of PubMed, Scopus, and the Cochrane Library databases using PRISMA guidelines was performed to include case-control studies, cohorts, and clinical trials reporting complication data for CP after DC. Information about the patients' characteristics and the rates of overall and specific complications in TBI and non-TBI patients was extracted, summarized, and analyzed.A total of 59 studies, including the authors' institutional experience, encompassing 9264 patients (4671 TBI vs. 4593 non-TBI) met the inclusion criteria; this total also included 149 cases from our institutional series. The results of the analysis of the published series are shown both with and without our series 23 studies reported overall complications, 40 reported infections, 10 reported new-onset seizures, 13 reported bone flap resorption (BFR), 5 reported post-CP hydrocephalus, 10 reported intracranial hemorrhage (ICH), and 8 reported extra-axial fluid collections (EFC). TBI was associated with increased odds of BFR (odds ratio [OR] 1.76, p < 0.01) and infection (OR 1.38, p = 0.02). No difference was detected in the odds of overall complications, seizures, hydrocephalus, ICH, or EFC.Awareness of increased risks of BFR and infection after CP in TBI patients promotes the implementation of new strategies to prevent these complications especially in this category of patients.

Clinical impact of high-profile animal-based research reported in the UK national press

OBJECTIVES

We evaluated animal-based biomedical 'breakthroughs' reported in the UK national press in 1995 (25 years prior to the conclusion of this study). Based on evidence of overspeculative reporting of biomedical research in other areas (eg, press releases and scientific papers), we specifically examined animal research in the media, asking, 'In a given year, what proportion of animal research "breakthroughs"' published in the UK national press had translated, more than 20 years later, to approved interventions?'

METHODS

We searched the Nexis media database (LexisNexis.com) for animal-based biomedical reports in the UK national press. The only restrictions were that the intervention should be specific, such as a named drug, gene, biomedical pathway, to facilitate follow-up, and that there should be claims of some clinical promise.

MAIN OUTCOME MEASURES

Were any interventions approved for human use? If so, when and by which agency? If not, why, and how far did development proceed? Were any other, directly related interventions approved? Did any of the reports overstate human relevance?

RESULTS

Overspeculation and exaggeration of human relevance was evident in all the articles examined. Of 27 unique published 'breakthroughs', only one had clearly resulted in human benefit. Twenty were classified as failures, three were inconclusive and three were partially successful.

CONCLUSIONS

The results of animal-based preclinical research studies are commonly overstated in media reports, to prematurely imply often-imminent 'breakthroughs' relevant to human medicine.

Use of Onlay Hydroxyapatite Cement for Secondary Cranioplasty

BACKGROUND

Children who undergo bi-fronto-orbital advancement (BFOA) frequently develop a contour deformity on the temporal and supra-orbital region, with an incidence reported as high as 55% and 75%, respectively. Up to 20% of patients may require correction. Hydroxyapatite cement (HAC) is a good alternative to autogenous tissue. The available literature on its use focusses on the reconstruction of bone defects, but little has been published on its efficacy and safety as an onlay graft over intact cranium.

OBJECTIVES

To describe our institution's experience with HAC in the pediatric population.

METHODS

Retrospective chart review from 1998 to 2018 on all patients from the Craniofacial Unit at the Sydney Children's Hospital who had either coronal or metopic craniosynostosis and underwent BFOA and later in life required cranioplasty with HAC for contour repair.

FINDINGS

We have performed 166 BFOA and nineteen secondary cranioplasties for contour repair using onlay HAC. The mean age at the time of operation was 14 years. Bi-coronal craniosynostosis was most frequently associated with secondary cranioplasty and 37% had an associated syndrome. The mean volume of HAC used was 37 mL. There was only 1 patient who had a complication (5.3%) and required partial removal of allograft. The mean length of admission was 2 days. Mean follow up time of 22.4 months.

CONCLUSIONS

HAC represents a safe option when used correctly, with low rates of complication and satisfactory cosmetic outcomes.

Temporal Fat Grafting in Children With Craniofacial Anomalies

BACKGROUND

Fat grafting is a common adjunct procedure used to treat temporal fat hollowing in children with craniofacial anomalies. The goal of this study was to assess the surgical and aesthetic outcomes of this procedure.

METHODS

We retrospectively reviewed patients who underwent temporal fat grafting at a single tertiary pediatric craniofacial center. The surgical outcome was assessed based on intraoperativeand 30-day postoperative complication rates. The aesthetic outcome was assessed by 3 independent investigators using a 3-point grading scale for preoperative temporal hollowing severity (1 = mild, 2 = moderate, 3 = severe) and a 5-point scale for postoperative improvement (0 = no, 1 = mild, 2 = moderate, 3 = significant, and 4 = complete improvement).

RESULTS

Forty-three patients met inclusion criteria. Twenty-seven (63%) were male, 39 (91%) had a history of craniosynostosis, and 18 (42%) had associated syndromes. The mean age at fat grafting was 9.9 years (2.7-20.4, SD = 5.5) with an average follow-up time of 1.6 years (0-5.8, SD = 1.8). The average volume of fat grafted was 8.6 mL (0-30, SD = 5.9) to the right temporal region and 8.6 mL (0-30, SD = 5.8) to the left. There were no intraoperative or postoperative complications. The mean improvement score was 2.9 (1-4, SD = 0.7), demonstrating that most patients experienced moderate to significant improvement. Multiple linear regression analysis demonstrated that syndromic status had a negative impact on the aesthetic outcome (P < 0.001).

CONCLUSIONS

These findings demonstrate that fat grafting is an effective method to treat temporal hollowing in children with craniofacial anomalies with no perioperative complications.

A retrospective descriptive study of cranioplasty failure rates and contributing factors in novel 3D printed calcium phosphate implants compared to traditional materials

BACKGROUND

Failure rates with cranioplasty procedures have driven efforts to improve graft material and reduce reoperation. One promising allograft source is a 3D-printed titanium mesh with calcium phosphate filler. This study evaluated failure rates and pertinent characteristics of these novel 3D-grafts compared to traditional materials.

METHODS

Sixty patients were retrospectively identified who underwent a cranioplasty between January 2015-December 2017. Specific data points related to graft failure were collected for all surgical admissions, from the primary injury to their most recent. These included, but were not limited to, initial physical exam findings, vitals, comorbid conditions, surgery length, estimated blood loss, incision type, and need for revision. Failure rates of 3D-printed allografts were compared to traditional grafts.

RESULTS

A total of 60 subjects were identified who underwent 71 unique cranioplasty procedures (3D = 13, Synthetic = 12, Autologous = 46). There were 14 total failures, demonstrating a 19.7% overall failure rate. Specifically, 15.4% (n = 2) of 3D, 19.6% (n = 9) of autologous, and 25.0% (n = 3) of synthetic grafts required revision. Patients receiving 3D-grafts had the shortest overall mean surgery times (200.8 ± 54.3 min) and lowest infection rates (7.7%) compared to autologous (210.5 ± 47.9 min | 25.0%) and synthetic models (217.6 ± 77.3 min | 8.7%), though significance was unable to be determined. Tobacco use and trap-door incisions were associated with increased failure rates relative to straight or curved incisions in autologous grafts. Cranioplasties performed less than 3 months after craniectomy appeared to fail more often than those performed at least three months after craniectomy, for the synthetic group.

CONCLUSION

We concluded that 3D-printed cranioplasty grafts may lead to lower failure rates and shorter surgery times compared to traditional cranioplasty materials in our limited population. 3D-implants hold promise for cranial reconstruction after TBI.

Free Dermal Fat Autografting for Complex Craniofacial Wounds

Complex craniofacial wounds (CCW) are those refractory to initial treatment and may involve chronic infection, exposed hardware, irradiated tissue, and soft tissue volume loss. Typical reconstruction with microvascular flaps involves considerable morbidity. While free dermal fat autografting (DFA) is used extensively in many applications, its use treating CCW remains an unexplored but attractive possibility. Data from a retrospective cohort of 34 consecutive patients (13 male; 21 female and aged 2-79-years), who underwent free DFA between 1985 and 2018 for CCW by a single plastic surgeon, were analyzed. Post-operative follow-up was 1-24 years (M = 6.53, SD = 7.91). Many patients had several concomitant wound complications. Primary pre-operative wound complications were dominated by infection (N = 20), of which over 75% (N = 15) were associated with non-autogenic material. Eighteen had resolution of their pre-operative infection. Of the total (N = 34), 79.41% had stable grafts at follow-up [X(3) = 54, P < 0.001], with only 3 experiencing observable atrophy and 1 graft necrosis. Most of the cohort was complication free [X(1) = 7.53, P = 0.006], with 73.53% experiencing no problems involving the graft. Twenty-nine (85.29%) of 34 patients had therapeutic success with free DFA [X(1) = 28.65, P < 0.001]. Pre-operative wound status (β = 1.13, P < 0.001) predicted therapeutic success [R = 0.87, F(7,9) = 8.94, P = 0.002]. While 5 (14.71%) did not have therapeutic success, no additional problems arose related to grafts. Free DFA appears to be beneficial and show low morbidity. Future studies must evaluate these findings. In this context, their use should be considered in recalcitrant craniofacial wounds.

Cranioplasty after craniectomy in pediatric patients-a systematic review

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Hydroxyapatite cement cranioplasty for translabyrinthine surgery: A single institution experience

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

4 Laryngoscope, 130:206-211, 2020.

Pediatric Cranioplasty

Historically, the approach to pediatric cranioplasty has been largely extrapolated from the treatment of adults. More recently, however, the intricacies of pediatric cranial reconstruction have become better understood, and the surgical management has been refined contemporaneously. Each patient's cranial defect bears a unique set of challenges and, as such, the choice of cranioplasty technique must be tailored accordingly.

Complications after craniofacial reconstruction with calcium phosphate cements: a case report and review of the literature

Among different graft materials for craniofacial reconstruction, calcium phosphate cements have the advantages of alloplastic grafts and wide use. The authors report a case of foreign body reaction following frontal reconstruction with JectOS (an injectable calcium orthophosphate cement; Kasios) and reviewed the literature on complications of this material after craniofacial reconstruction from 2002 to 2017. Complications were categorized into two groups: immunologic reactions (consisting of seroma collection, chronic sinus mucosa swelling, and foreign body reaction) and non-immune events (infection, fragmentation, and ejection). It is wise to use calcium phosphate-based material only in selected cases with small defects, and long-term follow-up is needed to observe their consequences.

Autologous Bone Is Inferior to Alloplastic Cranioplasties: Safety of Autograft and Allograft Materials for Cranioplasties, a Systematic Review

BACKGROUND

Currently, various materials are routinely used for cranioplasty after decompressive craniectomy, each with their own features, potential benefits, and harms.

OBJECTIVES

To systematically review available literature about safety (infection, resorption, and removal) of different materials used for cranioplasty for any indication.

METHODS

A comprehensive search in MEDLINE, EMBASE, and the Cochrane library was performed for relevant studies published up to January 2017. Study quality was assessed according to the Cochrane Collaboration risk of bias assessment tool, and a set of 27 predetermined parameters was extracted by 2 investigators independently for further analysis.

RESULTS

The search yielded 2 randomized, 14 prospective, and 212 retrospective studies, totaling 10,346 cranioplasties in which 1952 (18.9%) complications were reported in patients between 0 and 90 years old. Overall, study quality was low and heterogeneity was large. Graft infections and resorption were most prevalent: overall infection rate was 5.6%. Autologous cranioplasties showed an infection rate of 6.9% versus 5.0% in combined alloplastic materials, including poly(methyl methacrylate) with 7.8%. Resorption occurred almost exclusively in autologous cranioplasties (11.3%). The greatest removal rate was reported for autologous cranioplasties (overall: 10.4%), which was significantly greater than that of combined alloplastic materials (overall: 5.1%; risk difference = 0.052 [95% confidence interval: 0.039-0.066]; NNT = 19 [95% confidence interval: 15-25]).

CONCLUSIONS

Available evidence on the safety of cranioplasty materials is limited due to a large diversity in study conduct, patients included, and outcomes reported. Autografts appear to carry a greater failure risk than allografts. Future publications concerning cranioplasties will benefit by a standardized reporting of surgical procedures, outcomes, and graft materials used.

Calvarial Reconstruction

Calvarial reconstruction is a challenge to reconstructive surgeons, especially considering protection of intracranial contents. In recent years, the advent of multiple reconstructive materials adds tools to the surgical armamentarium. Options include autologous split calvarial and rib grafts and alloplastic materials such as titanium mesh, methyl methacrylate, calcium hydroxyapatite, and polyetheretherketone. The most important aspect of cranial reconstruction still lies in finding the most aesthetic, safe, and reliable means of filling a defect.

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

OBJECTIVE

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

METHODS

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

OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

Autogenous Bone Reconstruction of Large Secondary Skull Defects

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Polymethylmethacrylate imbedded with antibiotics cranioplasty: An infection solution for moderate and large defects reconstruction?

Background:

In cases where autologous bone graft reconstruction is not possible (such as comminuted fractures, bone graft reabsorption, or infection) and the use of synthetic material is required, polymethylmethacrylate (PMMA) use is a safe and efficient solution. Studies comparing the incidence of postoperative complications between autologous and synthetic cranioplasty are heterogeneous, not allowing a conclusion of which is the best material for skull defects reconstruction. Current medical literature lacks prospective well-delineated studies with long-term follow-up that analyze the impact of antibiotic use in PMMA cranial reconstruction of moderate and large defects.

Methods:

A prospective series of patients, who underwent cranioplasty reconstruction with PMMA impregnated with antibiotic, were followed for 2 years. Authors collected data regarding demographic status, clinical conditions, surgical information, and its complications.

Results:

A total of 58 patients completed full follow-up with a mean group age of 40 years and a male predominance (77%). Major complications that required surgical management were identified in 5 patients, and 10 patients evolved with minor complications. Postoperative surgical site infection incidence was 3.2%.

Conclusion:

The infection rate in patients submitted to PMMA flap cranioplasty impregnated with antibiotic is significantly inferior comparing to the data described in medical literature. A lower infection incidence impacts secondary endpoints such as minimizing surgical morbidity, mortality, hospitalization period, and, consequently, costs.

A comparison and cost analysis of cranioplasty techniques: autologous bone versus custom computer-generated implants

BACKGROUND

Cranioplasty can be performed either with gold-standard, autologous bone grafts and osteotomies or alloplastic materials in skeletally mature patients. Recently, custom computer-generated implants (CCGIs) have gained popularity with surgeons because of potential advantages, which include preoperatively planned contour, obviated donor-site morbidity, and operative time savings. A remaining concern is the cost of CCGI production. The purpose of the present study was to objectively compare the operative time and relative cost of cranioplasties performed with autologous versus CCGI techniques at our center.

METHODS

A review of all autologous and CCGI cranioplasties performed at our institution over the last 7 years was performed. The following operative variables and associated costs were tabulated: length of operating room, length of ward/intensive care unit (ICU) stay, hardware/implants utilized, and need for transfusion.

RESULTS

Total average cost did not differ statistically between the autologous group (n = 15; $25,797.43) and the CCGI cohort (n = 12; $28,560.58). Operative time (P = 0.004), need for ICU admission (P < 0.001), and number of complications (P = 0.008) were all statistically significantly less in the CCGI group. The length of hospital stay and number of cases needing transfusion were fewer in the CCGI group but did not reach statistical significance.

CONCLUSION

The results of the present study demonstrated no significant increase in overall treatment cost associated with the use of the CCGI cranioplasty technique. In addition, the latter was associated with a statistically significant decrease in operative time and need for ICU admission when compared with those patients who underwent autologous bone cranioplasty.

LEVEL OF EVIDENCE

IV, therapeutic.

Reduced CSF leak in complete calvarial reconstructions of microvascular decompression craniectomies using calcium phosphate cement

OBJECT

Calcium phosphate cement provides a biomaterial that can be used for calvarial reconstruction in a retrosigmoid craniectomy for microvascular decompression (MVD). This study evaluates the outcomes of postoperative CSF leak and wound infection for patients undergoing a complete cranioplasty using calcium phosphate cement versus incomplete cranioplasty using polyethylene titanium mesh following a retrosigmoid craniectomy for MVD.

METHODS

The authors evaluated 211 cases involving patients who underwent first-time retrosigmoid craniectomies performed by a single attending surgeon fortrigeminal neuralgia from October 2008 to June 2014. From this patient population, 111 patients underwent calvarial reconstruction after retrosigmoid craniectomy using polyethylene titanium mesh, and 100 patients had reconstructions using calcium phosphate cement. A Pearson's chi-square test was used to compare postoperative complications of CSF leak and wound infection in these 2 types of cranioplasties.

RESULTS

The polyethylene titanium mesh group included 5 patients (4.5%) with postoperative CSF leak or pseudomeningocele and 3 patients (2.7%) with wound infections. In the calcium phosphate cement group, no patients had a CSF leak, and 2 patients (2%) had wound infections. This represented a statistically significant reduction of postoperative CSF leak in patients who underwent calcium phosphate reconstructions of their calvarial defect compared with those who underwent polyethylene titanium mesh reconstructions (p = 0.03). No significant difference was seen between the 2 groups in the number of patients with postoperative wound infections.

CONCLUSIONS

Calcium phosphate cement provides a viable alternative biomaterial for calvarial reconstruction of retrosigmoid craniectomy defects in patients who have an MVD. The application of this material provides a biocompatible barrier that reduces the incidence of postoperative CSF leaks.

Mechanical strength and in vitro antibiotic release profile of antibiotic-loaded calcium phosphate bone cement

Some case reports described the usage of bone cement mixed with antibiotics. However, there are few studies that referred to experimental research of calcium phosphate cement with antibiotics. Thus, we mixed vancomycin and amikacin with bone cement in various concentrations and examined its characterization and antibacterial activity. As a result, 6.25 wt% over the concentration could not mix with cement. With an increase in the antibiotic content, the hardening time was prolonged and the compressive strength tended to decrease. In consistency, vancomycin mixed cement increased, whereas amikacin mixed cement decreased. The elution of antibiotics showed sustained release. In conclusion, the characteristics of the bone cement changed based on the amount of antibiotics added, and calcium phosphate cement is useful as a drug carrier.

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

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

Evaluation of antibiotic-loaded calcium phosphate bone cement in an cranium-infected experimental model

Treatment of calvarial defects has remained a challenge in reconstruction surgery, especially because of infection at these sites. We produced a bactericidal biomaterial for treating infected bone defects by using calcium phosphate bone cement mixed with antibiotics. We evaluated the usefulness of this material mixed with the antibiotic vancomycin in a cranium-infected rat model. The concentration of vancomycin used was 5.0 wt%, as reported in our previous study. In order to establish the rat model, a cranium defect (diameter, 5 mm) was made that was infected with methicillin-resistant Staphylococcus aureus (MRSA). Thirty-six rats were divided into 6 groups depending on whether an autologous graft or bone cement with or without antibiotic was used for the defect. After 1 and 4 weeks, abscess formation was checked, tissue bacterial counts were determined, and pathological examination was performed. At both 1 and 4 weeks, no MRSA was detected on tissue bacterial culture or pathological examination in groups that received bone cement with antibiotics. In groups that received bone cement without antibiotic, MRSA was detected, and the bone cement had compromised and disintegrated into several slices. In conclusion, bone cement that contains antibiotics appears to be effective not only for reconstruction in cases of cranial defect, but also in terms of preventing infection.

Outcomes of calvarial reconstruction in cancer patients

BACKGROUND

Limited data exist on outcomes of calvarial reconstruction in cancer patients, including the relative efficacy of various cranioplasty materials, and risk factors for complications.

METHODS

A retrospective review was performed of cancer patients who underwent calvarial reconstruction over a 12-year period.

RESULTS

A total of 269 patients underwent 289 calvarial reconstructions. Materials used for cranioplasty included titanium mesh (49.8 percent), methylmethacrylate (16.3 percent), porous polyethylene (4.8 percent), polyetheretherketone (4.5 percent), calcium phosphate cement (3.8 percent), autologous bone grafts (2.1 percent), or a combination of materials (18.3 percent). Perioperative (≤30 days after surgery) complications occurred in 42 cases (14.5 percent), of which 29 (10.0 percent) were at the recipient site, most commonly infection (2.8 percent) and cerebrospinal fluid leak (2.4 percent). Risk factors for perioperative complications included radiation therapy (p = 0.012), prior surgery (p = 0.003), and prior infection (p = 0.014). Late recipient-site complications (>30 days after surgery) occurred in 20 cases (6.9 percent), including infection (3.8 percent) and wound dehiscence (3.1 percent), and for which radiation therapy was identified as a risk factor (p = 0.011). The use of calcium phosphate cement in combination with titanium mesh was associated with a higher long-term complication rate (p < 0.001). Twenty-five cases (8.7 percent) required cranioplasty removal, with infection and dehiscence being risk factors for implant loss (p < 0.001 for both).

CONCLUSIONS

Alloplastic cranioplasty is effective in cancer patients with calvarial defects. Commonly used materials have similar complication profiles, with the possible exception of calcium phosphate cement, which is associated with a higher rate of complications when combined with titanium mesh and used to reconstruct larger defects.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Endoscopic delivery of calcium phosphate cement for secondary craniofacial reconstruction

Contour defects are common following primary craniofacial procedures including cranial vault remodeling, fronto-orbital and midface advancements, and complex posttraumatic reconstructions. When onlayed as fast-setting pastes, calcium phosphate cements (CPCs) have been used to effectively correct contour defects in open secondary reconstruction procedures. Here, we describe an endoscopic procedure using an injectable CPC and compare surgical outcomes with the open technique. A retrospective review was conducted for 36 consecutive patients aged 3.0-28.9 years (mean, 10.1 years) who underwent secondary craniofacial reconstruction over a 3-year period. Patients were stratified into endoscopic or open groups depending on the surgical approach utilized. Mean operative time was significantly shorter (P < 0.001) for the endoscopic group (64 minutes) than for the open group (131 minutes). Similarly, hospital stay was significantly shorter (P = 0.005) in the endoscopic group than in the open group. There was also a significant difference with respect to cost (P < 0.001), with the endoscopic approach resulting in a per-patient cost savings of $2208.05. In conclusion, endoscopic delivery of CPC appears to be a safe, efficacious, and cost-effective method of performing secondary craniofacial reconstruction, with the additional benefits of decreased operative time and shorter postoperative hospital stay when compared with an open procedure.

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

BACKGROUND

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

OBJECTIVE

To investigate the outcomes following custom-made titanium cranioplasty.

METHODS

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

RESULTS

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

CONCLUSION

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

Effects of DCPD cement chemistry on degradation properties and cytocompatibility: comparison of MCPM/β-TCP and MCPM/HA formulations

Dicalcium phosphate dihydrate (DCPD) cements are attractive biomaterials for bone repair, and a number of different DCPD cement formulations have been proposed in the literature. In this study, we have specifically compared monocalcium phosphate monohydrate (MCPM)/hydroxyapatite (HA) and MCPM/β-tricalcium phosphate (β-TCP) formulations to test the hypothesis that DCPD cement chemistry affects the degradation properties and cytocompatibility of the cement. Using simple in vitro models we found that MCPM/β-TCP formulations degraded primarily by DCPD dissolution, which was associated with a slight pH drop and relatively low mass loss. Cytocompatibility testing of cement conditioned culture media revealed no significant change in cell viability relative to the negative control for all of the MCPM/β-TCP formulations. In contrast, the MCPM/HA formulations were prone to undergo rapid conversion of DCPD to HA, resulting in a sharp pH drop and extensive mass loss. A stoichiometric excess of HA in the cement was found to accelerate the conversion process, and significant cytotoxicity was observed for the MCPM/HA formulations containing excess HA. Collectively, these results show that, although the product of the setting reaction is the same, DCPD cements produced with MCPM/HA and MCPM/β-TCP formulations differ significantly in their degradation properties and cytocompatibility. These differences may have important implications for the selection of a DCPD cement formulation for clinical application.

Early resorption of an artificial bone graft made of calcium phosphate for cranioplasty: case report

The treatment of uncomplicated osteoma consists of an en bloc resection, or curettage, of the tumor, followed by cranioplasty. Here, we present a case report of a patient treated for a parietal osteoma, followed by a calcium phosphate cranioplasty, with early resorption after 3 months, which was presented by a sinking flap above the resection area. This case suggests that synthetic cranioplasty should be preferred, even in small skull-gap areas.

Transverse rectus abdominis myocutaneous flap combined with vascularized costal cartilages in cranial reconstruction

Exposing the alloplastic materials after skull reconstruction is very difficult because of the risk of infection and the choice of reconstruction procedures. Conventional procedures were divided into two-step or multi-step surgery.To perform one-stage surgery, a transverse rectus abdominis myocutaneous flap combined with vascularized costal cartilages has been used for head reconstruction after exposing the alloplastic materials in two patients. This is the first report using the flap for skull reconstruction.In this article, we describe the usefulness and the disadvantages of the transverse rectus abdominis myocutaneous flap combined with vascularized costal cartilages.

A review of reconstructive materials for use in craniofacial surgery bone fixation materials, bone substitutes, and distractors

Over the last 40 years, craniofacial surgery, in general, and surgery for craniosynostosis, in particular, has witnessed the introduction of a number of new materials for use in operations involving the cranial vault. Some of these materials have proven quite useful over time, while others have failed to meet their stated objectives. In this review, the more popular implant materials are analyzed, and their relative merits and drawbacks are discussed. Craniofacial surgery in the pediatric population has its own unique limitations, quite different from the adult population and those issues are reviewed as well.

Fiber-reinforced calcium phosphate cement formulations for cranioplasty applications: a 52-week duration preclinical rabbit calvaria study

The in vivo tissue response to a newly developed fiber-reinforced calcium phosphate cement (CPC) formulation was assessed using a well-established rabbit calvarial defect model. Bilateral subcritical sized (8-mm diameter) defects were surgically created in the parietal bones of each rabbit (a total of 48 rabbits), and randomized to be filled with either the new fiber-reinforced formulation, a conventional CPC (positive control), or left unfilled (negative control). The implant sites were subsequently retrieved after 12, 24, and 52 weeks postsurgery. Each specimen, including the parietal bone craniotomy and underlying brain, were recovered at necropsy and the tissue responses were assessed by histology. The resulting histological slides indicated that there was no evidence of severe inflammatory responses or osteolysis. The data showed new dural and pericranial bone formation along the implants, as well as excellent bone-to-implant interfaces in all of the CPC-filled defects. These results suggest that the biologic response to the new fiber-reinforced CPC formulations and conventional nonreinforced CPC are very similar, and both demonstrate excellent biocompatibility as well as an overall osteophylic response.