Two-Center Validation of the Oulu Resorption Score for Bone Flap Resorption after Autologous Cranioplasty

Abstract Background and Study Aims/Objective Cranioplasty, a common neurosurgical intervention following decompressive craniectomy (DC), is associated with high complication rates. Bone flap resorption in particular leads to a considerable number of patients requiring further surgery. The aim of this study was to investigate the frequency and time of occurrence of complications following cranioplastic procedures in children and adults. Material and Methods Data of children and adults who underwent cranioplasty between July 2010 and March 2018 were analyzed retrospectively. Clinical data, complications, and risk factors regarding aseptic bone resorption (ABR) were evaluated including patient age, occurrence of shunt-dependent hydrocephalus, and number of fragments in autologous bone flaps. Results Severe traumatic brain injury (TBI) was the leading cause for DC among children (66.7%), associated with a significantly higher number of fragments (p = 0.002). In the adult population, the most common cause was malignant infarction (55.9%) followed by TBI (24.6%). Pediatric patients in our institution received autologous bone flaps less frequently than adult patients (61.1% and 83.1%, respectively). Young age and a higher number of fragments in autologous bone flaps were associated with the occurrence of ABR. Children and adolescents showed significantly higher rates of aseptic bone necrosis (p = 0.007) and revision cranioplasty (p = 0.036). Kaplan-Meier estimates were used to further analyze bone flap resorption in children and adults, showing that revision surgery due to ABR was performed earlier in children (p = 0.001, log-rank test). Conclusion Pediatric patients demand specific care when cranioplasty is performed following DC. We identified age as an independent risk factor. The higher number of fragments appears to be a correlation due to the higher number of TBIs in children. Our data indicate that young age is the most important risk factor for the development of ABR as a frequent and early complication with a shorter revision-free time interval in children. Consequently, the uncritical use of cryopreserved autologous bone flaps should be questioned in this population.

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Cranial bone flap resorption—pathological features and their implications for clinical treatment

Neurosurgical Review ◽

10.1007/s10143-020-01417-w ◽

2020 ◽

Author(s):

Jennifer Göttsche ◽

Klaus C. Mende ◽

Anastasia Schram ◽

Manfred Westphal ◽

Michael Amling ◽

...

Keyword(s):

Bone Marrow ◽

Bone Structure ◽

Bone Flap ◽

Cranial Bone ◽

Time Interval ◽

Osteoblastic Activity ◽

Marrow Cavity ◽

Bone Flap Resorption ◽

Osteoclastic Resorption ◽

Underlying Processes

Abstract Cranioplasty following decompressive craniectomy (DC) has a primary complication when using the autologous bone: aseptic bone resorption (ABR). So far, risk factors such as age, number of fragments, and hydrocephalus have been identified but a thorough understanding of the underlying pathophysiology is still missing. The aim of this osteopathological investigation was to gain a better understanding of the underlying processes. Clinical data of patients who underwent surgical revision due to ABR was collected. Demographics, the time interval between craniectomy and cranioplasty, and endocrine serum parameters affecting bone metabolism were collected. Removed specimens underwent qualitative and quantitative histological examination. Two grafts without ABR were examined as controls. Compared to the controls, the typical layering of the cortical and cancellous bone was largely eliminated in the grafts. Histological investigations revealed the coexistence of osteolytic and osteoblastic activity within the necrosis. Bone appositions were distributed over the entire graft area. Remaining marrow spaces were predominantly fibrotic or necrotic. In areas with marrow cavity fibrosis, hardly any new bone tissue was found in the adjacent bone, while there were increased signs of osteoclastic resorption. Insufficient reintegration of the flap may be due to residual fatty bone marrow contained in the bone flap which seems to act as a barrier for osteogenesis. This may obstruct the reorganization of the bone structure, inducing aseptic bone necrosis. Following a path already taken in orthopedic surgery, thorough lavage of the implant to remove the bone marrow may be a possibility, but will need further investigation.

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Bone Flap Resorption: Mysterious Complication of Autologus Bone Flap Cranioplasty with Highly Variable Incidence in Pediatric, Adult, and Older Populations

World Neurosurgery ◽

10.1016/j.wneu.2017.02.077 ◽

2017 ◽

Vol 103 ◽

pp. 937-938 ◽

Cited By ~ 1

Author(s):

Guru Dutta Satyarthee

Keyword(s):

Bone Flap ◽

Bone Flap Resorption ◽

Older Populations

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Predictors of primary autograft cranioplasty survival and resorption after craniectomy

Journal of Neurosurgery ◽

10.3171/2017.12.jns172013 ◽

2019 ◽

Vol 130 (5) ◽

pp. 1672-1679 ◽

Cited By ~ 12

Author(s):

Tommi K. Korhonen ◽

Sami Tetri ◽

Jukka Huttunen ◽

Antti Lindgren ◽

Jaakko M. Piitulainen ◽

...

Keyword(s):

Removal Rate ◽

Bone Flap ◽

University Hospitals ◽

Neurosurgical Procedure ◽

Factors Affecting ◽

Bone Flap Resorption ◽

Multicenter Cohort ◽

Younger Age ◽

Autologous Bone

OBJECTIVECraniectomy is a common neurosurgical procedure that reduces intracranial pressure, but survival necessitates cranioplasty at a later stage, after recovery from the primary insult. Complications such as infection and resorption of the autologous bone flap are common. The risk factors for complications and subsequent bone flap removal are unclear. The aim of this multicenter, retrospective study was to evaluate the factors affecting the outcome of primary autologous cranioplasty, with special emphasis on bone flap resorption.METHODSThe authors identified all patients who underwent primary autologous cranioplasty at 3 tertiary-level university hospitals between 2002 and 2015. Patients underwent follow-up until bone flap removal, death, or December 31, 2015.RESULTSThe cohort comprised 207 patients with a mean follow-up period of 3.7 years (SD 2.7 years). The overall complication rate was 39.6% (82/207), the bone flap removal rate was 19.3% (40/207), and 11 patients (5.3%) died during the follow-up period. Smoking (OR 3.23, 95% CI 1.50–6.95; p = 0.003) and age younger than 45 years (OR 2.29, 95% CI 1.07–4.89; p = 0.032) were found to independently predict subsequent autograft removal, while age younger than 30 years was found to independently predict clinically relevant bone flap resorption (OR 4.59, 95% CI 1.15–18.34; p = 0.03). The interval between craniectomy and cranioplasty was not found to predict either bone flap removal or resorption.CONCLUSIONSIn this large, multicenter cohort of patients with autologous cranioplasty, smoking and younger age predicted complications leading to bone flap removal. Very young age predicted bone flap resorption. The authors recommend that physicians extensively inform their patients of the pronounced risks of smoking before cranioplasty.

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Bone Flap Resorption Following Cranioplasty after Decompressive Craniectomy: Preliminary Report

Korean Journal of Neurotrauma ◽

10.13004/kjnt.2015.11.1.1 ◽

2015 ◽

Vol 11 (1) ◽

pp. 1 ◽

Cited By ~ 11

Author(s):

Ji Sang Kim ◽

Jin Hwan Cheong ◽

Je Il Ryu ◽

Jae Min Kim ◽

Choong Hyun Kim

Keyword(s):

Decompressive Craniectomy ◽

Preliminary Report ◽

Bone Flap ◽

Bone Flap Resorption

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Initial Dead Space and Multiplicity of Bone Flap as Strong Risk Factors for Bone Flap Resorption after Cranioplasty for Traumatic Brain Injury

Korean Journal of Neurotrauma ◽

10.13004/kjnt.2018.14.2.105 ◽

2018 ◽

Vol 14 (2) ◽

pp. 105 ◽

Cited By ~ 1

Author(s):

Jeong Kyun Joo ◽

Jong-Il Choi ◽

Chang Hyun Kim ◽

Ho Kook Lee ◽

Jae Gon Moon ◽

...

Keyword(s):

Risk Factors ◽

Traumatic Brain Injury ◽

Brain Injury ◽

Dead Space ◽

Bone Flap ◽

Bone Flap Resorption

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Bone Flap Resorption Associated with Indolent Propionibacterium acnes Infection After Cranioplasty: Case Report with Pathological Analysis

World Neurosurgery ◽

10.1016/j.wneu.2020.03.077 ◽

2020 ◽

Vol 138 ◽

pp. 313-316 ◽

Cited By ~ 1

Author(s):

Nathan A. Shlobin ◽

Aaron H. Palmer ◽

Kwok-Ling Kam ◽

Daniel J. Brat ◽

Matthew B. Potts

Keyword(s):

Case Report ◽

Propionibacterium Acnes ◽

Bone Flap ◽

Pathological Analysis ◽

Bone Flap Resorption

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Letter to the Editor: Bone flap resorption in infants

Journal of Neurosurgery Pediatrics ◽

10.3171/2013.6.peds13312 ◽

2014 ◽

Vol 13 (2) ◽

pp. 243-244 ◽

Cited By ~ 12

Author(s):

Paolo Frassanito ◽

Luca Massimi ◽

Massimo Caldarelli ◽

Gianpiero Tamburrini ◽

Concezio Di Rocco

Keyword(s):

Bone Flap ◽

Bone Flap Resorption ◽

Letter To The Editor

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Quantitative and qualitative analysis of bone flap resorption in patients undergoing cranioplasty after decompressive craniectomy

Journal of Neurosurgery ◽

10.3171/2017.8.jns171857 ◽

2018 ◽

Vol 130 (1) ◽

pp. 312-321 ◽

Cited By ~ 6

Author(s):

Tommi K. Korhonen ◽

Niina Salokorpi ◽

Jaakko Niinimäki ◽

Willy Serlo ◽

Petri Lehenkari ◽

...

Keyword(s):

Decompressive Craniectomy ◽

Mechanical Stability ◽

University Hospital ◽

Bone Flap ◽

Ct Scans ◽

Bone Flap Resorption ◽

Intact Bone ◽

Partial Resorption

OBJECTIVEAutologous bone cranioplasty after decompressive craniectomy entails a notable burden of difficult postoperative complications, such as infection and bone flap resorption (BFR), leading to mechanical failure. The prevalence and significance of asymptomatic BFR is currently unclear. The aim of this study was to radiologically monitor the long-term bone flap survival and bone quality change in patients undergoing autologous cranioplasty.METHODSThe authors identified all 45 patients who underwent autologous cranioplasty at Oulu University Hospital, Finland, between January 2004 and December 2014. Using perioperative and follow-up CT scans, the volumes and radiodensities of the intact bone flap prior to surgery and at follow-up were calculated. Relative changes in bone flap volume and radiodensity were then determined to assess cranioplasty survival. Sufficient CT scans were obtainable from 41 (91.1%) of the 45 patients.RESULTSThe 41 patients were followed up for a median duration of 3.79 years (25th and 75th percentiles = 1.55 and 6.66). Thirty-seven (90.2%) of the 41 patients had some degree of BFR and 13 (31.7%) had a remaining bone flap volume of less than 80%. Patients younger than 30 years of age had a mean decrease of 15.8% in bone flap volume compared with the rest of the cohort. Bone flap volume was not found to decrease linearly with the passing of time, however. The effects of lifestyle factors and comorbidities on BFR were nonsignificant.CONCLUSIONSIn this study BFR was a very common phenomenon, occurring at least to some degree in 90% of the patients. Decreases in bone volume were especially prominent in patients younger than 30 years of age. Because the progression of resorption during follow-up was nonlinear, routine follow-up CT scans appear unnecessary in monitoring the progression of BFR; instead, clinical follow-up with mechanical stability assessment is advised. Partial resorption is most likely a normal physiological phenomenon during the bone revitalization process.

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