Low Incidence of Bone Flap Resorption After Native Bone Cranioplasty in Adults

doi:10.1016/j.wneu.2016.04.115

World Neurosurgery

Volume 92, August 2016, Pages 89-94

https://doi.org/10.1016/j.wneu.2016.04.115 Get rights and content

Objective

Cranioplasty via use of the patient's autologous bone is performed often after craniectomy procedures. Bone resorption remains a matter of concern in patients with native bone cranioplasty. The objective of this study was to evaluate the rate of native bone resorption in adults and review associated factors that may increase the risk of resorption.

Methods

This is a single-center retrospective cohort study that assessed consecutive patients who had cranioplasty via use of the patient's native bone flap. A total of 114 patients were identified. Electronic medical records were reviewed for demographic and operative data.

Results

The mean age was 51.2 years. The main indications for initial craniectomy included subarachnoid hemorrhage (SAH) in 50.9%, intracerebral hemorrhage in 17.5%, ischemic stroke in 14.9%, and trauma in 13.2% of patients. Mean interval between craniectomy and cranioplasty was 6 months. Mean follow-up after cranioplasty was 25 months. Bone resorption occurred in 3 patients (2.7%): at 6 months in a 30-year-old woman who presented with SAH followed by decompressive craniectomy and cranioplasty 3.5 months later; at 19 months in a 67-year-old female patient who presented with intracerebral hemorrhage followed by decompressive craniectomy and cranioplasty 6 months later; and at 9 months in a 50-year-old man who presented with SAH followed by craniectomy for clip ligation and cranioplasty 3 months later. Two of these patients underwent replacement of the native flap with synthetic material.

Conclusions

The rate of autologous bone flap resorption in adult patients undergoing cranioplasty is low even after a mean interval for cranioplasty of 6 months.

Introduction

Cranioplasty is performed for protective, cosmetic, and therapeutic reasons in surviving patients who have undergone craniectomy previously for the management of space-occupying intracranial pathologies, including intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), traumatic brain injury, malignant cerebral edema after acute ischemic stroke, or various brain tumors and intracranial infections.1, 2, 3 Several materials can be used to repair the cranial defect. The traditional and most commonly used method is autologous bone graft with reinsertion of the native bone flap. This method is especially preferred in pediatric patients because of the potential reintegration of the flap as the patient grows up without introducing other foreign materials. Other materials that can be used to repair the defect include polymethyl methacrylate, hydroxyapatite cement, titanium mesh, or metal plates.⁴

Cranioplasty is associated with an important rate of complications, up to 34%.⁵ The main complications include infection, postoperative hematoma formation, hydrocephalus, seizures, and bone resorption.6, 7 Bone resorption remains a matter of concern in patients with native bone cranioplasty because it may result in cosmetic flaws and increased risk of brain injury and may require reoperation and replacement of the flap with other materials. The rate of bone resorption after native cranioplasty has been reported to be as low as 2% and as high as 32% in adult patients8, 9 and even greater in pediatric patients after autologous cranioplasty.10, 11, 12 Several factors pertaining to the cranioplasty procedure, such as the condition of the native bone flap, storage techniques, time to reinsertion of the bone flap, and patient characteristics, have been reported to influence the rate of bone resorption. The aim of this study is to evaluate the rate of bone flap resorption in an adult population and review associated factors that may increase the risk of this event in patients with native bone cranioplasty.

Section snippets

Patient Selection

The study protocol was approved by the University Institutional Review Board. This is a single-center retrospective cohort study that assessed consecutive patients who had a cranioplasty procedure in which their native bone flap was used, performed by the neurovascular department during a 10-year period. Adult patients (>18 years of age) who underwent cranioplasty after craniectomy for increased intracranial pressure as the result of SAH, ischemic stroke, intraparenchymal hemorrhage,

Results

In the 114 patients identified, the mean age at the time of cranioplasty was 51.2 years (Table 1); 53% of patients were women and 47% were men. A total of 41.2% of patients were smokers, 16.7% had a history of diabetes mellitus, and 60.5% of patients had a history of hypertension. The indications for the initial craniectomy procedure were SAH in 57 patients (50.9%), ICH in 20 patients (17.6%), ischemic stroke in 17 patients (14.9%), trauma in 15 patients (13.2%), subdural hematoma in 2 patients

Discussion

Bone flap resorption has been established as an important long-term complication after native bone cranioplasty.³ The reported rates of resorption after autologous cranioplasty have varied greatly. In the adult population, the incidence of bone flap resorption has ranged from 2% to as high as 32%.3, 5, 8, 9, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 Studies involving pediatric patients have reported even greater rates of bone flap resorption, from 29% to 50%,10, 11, 24 and up to 81.8% in 1

Conclusions

The rate of autologous bone flap resorption in adult patients undergoing cranioplasty after craniectomy for SAH, ICH, ischemic stroke, and trauma is low. Our results further show that the risk of resorption is low in cryopreserved bone flaps and the risk is still low after a mean interval for cranioplasty of 6 months. When native bone flap resorption occurs, it usually presents within the first 2 years. Important factors that have been associated with the occurrence of bone flap resorption

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Cited by (16)

Autologous Cranioplasty with Bone Flap Preserved in Conventional Freezers: An Adequate Option in Low Resource Settings
2024, World Neurosurgery
Autologous cranioplasty has been used for decades and is the gold standard treatment in patients who underwent decompressive craniectomy (DC). One of the most common methods to store the cranial bone flap is cryopreservation at very low temperatures (−70 to −80°). The only way to achieve these low temperatures is by using special freezers which are not always available in all medical facilities, especially in low-resource centers. This paper describes our experience with the storage of cranial bone flaps in freezers of conventional refrigerators.
This retrospective study included patients treated with autologous cranioplasty, operated between 2015 and 2020. The cranial bone flap was stored at −18°C in the freezer of conventional refrigerators. Complications and outcomes were analyzed and compared with reports of patients in whom ultra-low temperature freezers were used for bone flap preservation.
Twenty-five patients were included. The average follow-up period was 33 months. Trauma was the most common cause of DC, followed by stroke. The mean age was 36.7. Aseptic bone flap resorption was observed in 4 cases (16%). No cases of infection were observed.
The use of freezers from conventional refrigerators may be an acceptable alternative for the preservation of the cranial bone flap in facilities where special freezers are not available. The rate of aseptic bone necrosis and infections observed in this paper was similar to the incidence of these complications reported in studies where ultra-low temperatures were used.
Bone Flap Resorption After Cranioplasty: Risk Factors and Proposal of the Flap Integrity Score
2024, World Neurosurgery
Bone flap resorption is a known complication of postdecompressive autologous cranioplasty. Although several potential etiopathogenetic factors have been investigated, their role is still under discussion. To further complicate things, resorption is not an all-or-nothing event, patients frequently presenting with different degrees of flap remodeling. Focus of this paper was to describe the elaboration of a score quantifying bone resorption according to a set of clinical and radiological criteria, hopefully allowing prompt identification of patients needing resurgery before the development of adverse events.
In a 10-year period, 281 autologous cranioplasties were performed at our institution following decompressive craniectomy. Pertinent clinical and radiological information was registered. A set of 3 clinical and 3 radiological parameters was established to score the degree of resorption, identified under the acronym FIS (Flap Integrity Score). Three groups of patients emerged, respectively showing no (208), partial (32), and advanced (41) resorption.
An overall 14.6% incidence of advanced bone resorption was found in our series. Younger age, bone multifragmentation, higher postcranioplasty Glasgow Outcome Scale scores, <2 cm distance of medial craniectomy border from the midline, and cause leading to decompressive craniectomy were associated to a statistically significant higher risk of developing a relevant bone flap resorption. The first three variables were confirmed as risk factors in multivariate analysis. Flap Integrity Score well discriminated the 3 different groups.
Autologous bone repositioning is still a valuable, low-cost, cosmetically and functionally satisfactory procedure. Nonetheless, although resorption affects a minor percentage of patients, its early identification and treatment can improve long-term results.
Infection-related failure of autologous versus allogenic cranioplasty after decompressive hemicraniectomy – A systematic review and meta-analysis
2023, Brain and Spine
Cranioplasty is required after decompressive craniectomy (DC) to restore brain protection and cosmetic appearance, as well as to optimize rehabilitation potential from underlying disease. Although the procedure is straightforward, complications either caused by bone flap resorption (BFR) or graft infection (GI), contribute to relevant comorbidity and increasing health care cost. Synthetic calvarial implants (allogenic cranioplasty) are not susceptible to resorption and cumulative failure rates (BFR and GI) tend therefore to be lower in comparison with autologous bone. The aim of this review and meta-analysis is to pool existing evidence of infection-related cranioplasty failure in autologous versus allogenic cranioplasty, when bone resorption is removed from the equation.
A systematic literature search in PubMed, EMBASE, and ISI Web of Science medical databases was performed on three time points (2018, 2020 and 2022). All clinical studies published between January 2010 and December 2022, in which autologous and allogenic cranioplasty was performed after DC, were considered for inclusion. Studies including non-DC cranioplasty and cranioplasty in children were excluded. The cranioplasty failure rate based on GI in both autologous and allogenic groups was noted. Data were extracted by means of standardized tables and all included studies were subjected to a risk of bias (RoB) assessment using the Newcastle-Ottawa assessment tool.
A total of 411 articles were identified and screened. After duplicate removal, 106 full-texts were analyzed. Eventually, 14 studies fulfilled the defined inclusion criteria including one randomized controlled trial, one prospective and 12 retrospective cohort studies. All but one study were rated as of poor quality based on the RoB analysis, mainly due to lacking disclosure why which material (autologous vs. allogenic) was chosen and how GI was defined. The infection-related cranioplasty failure rate was 6.9% (125/1808) for autologous and 8.3% (63/761) for allogenic implants resulting in an OR 0.81, 95% CI 0.58 to 1.13 (Z = 1.24; p = 0.22).
In respect to infection-related cranioplasty failure, autologous cranioplasty after decompressive craniectomy does not underperform compared to synthetic implants. This result must be interpreted in light of limitations of existing studies. Risk of graft infection does not seem a valid argument to prefer one implant material over the other. Offering an economically superior, biocompatible and perfect fitting cranioplasty implant, autologous cranioplasty can still have a role as the first option in patients with low risk of developing osteolysis or for whom BFR might not be of major concern.
This systematic review was registered in the international prospective register of systematic reviews. PROSPERO: CRD42018081720.
Risk factors for the development of seizures after cranioplasty in patients that sustained traumatic brain injury: A systematic review
2019, Seizure
Citation Excerpt :
In this group, an increasingly common surgical management option is decompressive craniectomy (DC), involving the removal of a bone flap to allow the brain to swell while relieving ICP [3,4]. The removed flap may be stored in an abdominal pouch or a specialised refrigeration unit, or discarded depending on factors such as infection and surgeon preference [5,6]. After acute swelling of the brain resolves, cranioplasty is performed to restore the integrity of the skull and cerebrospinal fluid dynamics [7].
Decompressive craniectomy (DC) is used for the treatment of raised intracranial pressure secondary to traumatic brain injury. Cranioplasty is a reconstructive procedure that restores the structural integrity of the skull following (DC). Seizures are a recognised complication of cranioplasty but its incidence and risk factors in TBI patients are unclear. Accurate prognostication can help direct prophylactic and treatment strategies for seizures. In this systematic review, we aim to evaluate current literature on these factors. A PROSPERO-registered systematic review was performed in accordance with PRISMA guidelines. Data was synthesised qualitatively and quantitatively in meta-analysis where appropriate.
A total of 8 relevant studies were identified, reporting 919 cranioplasty patients. Random-effects meta-analysis reveals a pooled incidence of post-cranioplasty seizures (PCS) of 5.1% (95% CI 2.6–8.2%). Identified risk factors from a single study included increasing age (OR 6.1, p = 0.006), contusion at cranioplasty location (OR 4.8, p = 0.015), and use of monopolar diathermy at cranioplasty (OR 3.5, p = 0.04). There is an association between an extended DC-cranioplasty interval and PCS risk although it did not reach statistical significance (p = 0.062).
Predictive factors for PCS are poorly investigated in the TBI population to date. Heterogeneity of included studies preclude meta-analysis of risk factors. Further studies are required to define the true incidence of PCS in TBI and its predictors, and trials are needed to inform management of these patients.
Autologous Bone Is Inferior to Alloplastic Cranioplasties: Safety of Autograft and Allograft Materials for Cranioplasties, a Systematic Review
2018, World Neurosurgery
Currently, various materials are routinely used for cranioplasty after decompressive craniectomy, each with their own features, potential benefits, and harms.
To systematically review available literature about safety (infection, resorption, and removal) of different materials used for cranioplasty for any indication.
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.
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]).
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.
Complications of cranioplasty in relationship to traumatic brain injury: a systematic review and meta-analysis
2021, Neurosurgical Review

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: Conflict of interest statement: The authors declare that the content of this article was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Original ArticleLow Incidence of Bone Flap Resorption After Native Bone Cranioplasty in Adults

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Patient Selection

Results

Discussion

Conclusions

Neurological recovery after cranioplasty

Neurosurgery

Post-cranioplasty cerebrospinal fluid hydrodynamic changes: magnetic resonance imaging quantitative analysis

Neurol Res

Risk factors of aseptic bone resorption: a study after autologous bone flap reinsertion due to decompressive craniotomy

J Neurosurg

History of synthetic materials in alloplastic cranioplasty

Neurosurg Focus

Complications of cranioplasty following decompressive craniectomy: analysis of 62 cases

Neurosurg Focus

Predictors of cranioplasty complications in stroke and trauma patients

J Neurosurg

Complications following cranioplasty: incidence and predictors in 348 cases

J Neurosurg

Clinical outcome in cranioplasty: critical review in long-term follow-up

J Craniofac Surg

The use of frozen autogenous bone flaps in delayed cranioplasty revisited

Neurosurgery

Risk factors and rates of bone flap resorption in pediatric patients after decompressive craniectomy for traumatic brain injury

J Neurosurg Pediatr

Failure of autologous bone-assisted cranioplasty following decompressive craniectomy in children and adolescents

J Neurosurg

Autologous bone flap cranioplasty following decompressive craniectomy is combined with a high complication rate in pediatric traumatic brain injury patients

Acta Neurochir

Cranioplasty with autologous cryopreserved bone after decompressive craniectomy: complications and risk factors for developing surgical site infection

Acta Neurochir

Original Article
Low Incidence of Bone Flap Resorption After Native Bone Cranioplasty in Adults