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

Clinical article

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In patients who have undergone decompressive craniectomy, autologous bone flap reinsertion becomes necessary whenever the cerebral situation has consolidated. However, aseptic necrosis of the bone flap remains a concern. The aim of this study was to report possible perioperative complications in patients undergoing autologous bone flap reinsertion and to identify the risk factors that may predispose the bone flap to necrosis.


All patients admitted to the authors' neurosurgical department between September 1994 and June 2011 and who received their own cryoconserved bone flap after decompressive craniectomy were studied. The grade of the bone flap necrosis was classified into 2 types. Type II bone necrosis was characterized by aseptic resorption with circumscribed or complete lysis of tabula interna and externa requiring surgical revision. To define predisposing factors, a multivariate analysis was performed using bone necrosis as the dependent variable.


Among the 372 patients (mean age 48.6 years, 57.4% males) who received 414 bone flaps during the observation period, 134 (36.0%) had a diffuse traumatic brain injury, 69 (18.5%) had subarachnoid hemorrhage, 58 (15.6%) had cerebral infarction, 56 (15.1%) had extraaxial bleeding, 43 (11.6%) had intracerebral bleeding, and 12 (3.2%) had a neoplasm. Surgical relevant Type II bone flap necrosis occurred in 85 patients (22.8%) and 91 bone flaps, after a median time of 15 months (interquartile range [IQR], 10–33 months). In a multivariate analysis with Type II necrosis as the dependent variable, bone flap fragmentation with 2 (OR 3.35, 95% CI 1.59–7.01, p < 0.002) or more fragments (OR 24.00, 95% CI 10.13–56.84, p < 0.001), shunt-dependent hydrocephalus (OR 1.76, 95% CI 0.99–3.12, p = 0.04), and a younger age (OR 0.98, 95% CI 0.96–0.99, p = 0.004) was associated with a higher risk for the development of an aseptic bone flap necrosis.


In patients undergoing bone flap reinsertion after craniotomy, aseptic bone necrosis is an underestimated problem during long-term follow-up. Especially in younger patients with an expected good neurological recovery and a fragmented bone flap, an initial allograft should be considered because of an increased risk for aseptic bone flap necrosis.

Abbreviations used in this paper:ICP = intracranial pressure; IQR = interquartile range; SAH = subarachnoid hemorrhage.

Article Information

Drs. Dünisch and Walter contributed equally to this work.

Address correspondence to: Pedro Dünisch, M.D., Department of Neurosurgery, Hospital of the Friedrich Schiller University, Erlanger Allee 101, 07747 Jena, Germany. email: pedro.duenisch@med.uni-jena.de.

Please include this information when citing this paper: published online March 1, 2013; DOI: 10.3171/2013.1.JNS12860.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    Measuring the 2D size of the bone flap as A = π/4 × B × b.

  • View in gallery

    Different types of bone flap resorption according to our classification: Type I (left) with left-sided thinning of the flap and Type II (right) with a complete lysis of the bone within the flaps.


  • 1

    Beauchamp KMKashuk JMoore EEBolles GRabb CSeinfeld J: Cranioplasty after postinjury decompressive craniectomy: is timing of the essence?. J Trauma 69:2702742010

  • 2

    Carvi YNievas MNHöllerhage HG: Early combined cranioplasty and programmable shunt in patients with skull bone defects and CSF-circulation disorders. Neurol Res 28:1391442006

  • 3

    Chang VHartzfeld PLanglois MMahmood ASeyfried D: Outcomes of cranial repair after craniectomy. Clinical article. J Neurosurg 112:112011242010

  • 4

    Chieregato A: The syndrome of the sunken skin flap: a neglected potentially reversible phenomenon affecting recovery after decompressive craniotomy. Intensive Care Med 32:166816692006

  • 5

    Dujovny MFernandez PAlperin NBetz WMisra MMafee M: Post-cranioplasty cerebrospinal fluid hydrodynamic changes: magnetic resonance imaging quantitative analysis. Neurol Res 19:3113161997

  • 6

    Gooch MRGin GEKenning TJGerman JW: Complications of cranioplasty following decompressive craniectomy: analysis of 62 cases. Neurosurg Focus 26:6E92009

  • 7

    Grant GAJolley MEllenbogen RGRoberts TS: Failure of autologous bone-assisted cranioplasty following decompressive craniectomy in children and adolescents. J Neurosurg 100:2 Suppl Pediatrics1631682004

  • 8

    Häuptli JSegantini P: [New tissue preservation method for bone flaps following decompressive craniotomy.]. Helv Chir Acta 47:1211241980. (Ger)

  • 9

    Honeybul SHo KM: Long-term complications of decompressive craniectomy for head injury. J Neurotrauma 28:9299352011

  • 10

    Iwama TYamada JImai SShinoda JFunakoshi TSakai N: The use of frozen autogenous bone flaps in delayed cranioplasty revisited. Neurosurgery 52:5915962003

  • 11

    Joseph VReilly P: Syndrome of the trephined. Case report. J Neurosurg 111:6506522009

  • 12

    Kemmling ADuning TLemcke LNiederstadt TMinnerup JWersching H: Case report of MR perfusion imaging in sinking skin flap syndrome: growing evidence for hemodynamic impairment. BMC Neurol 10:802010

  • 13

    Liang WXiaofeng YWeiguo LGang SXuesheng ZFei C: Cranioplasty of large cranial defect at an early stage after decompressive craniectomy performed for severe head trauma. J Craniofac Surg 18:5265322007

  • 14

    Meyer MJMegyesi JMeythaler JMurie-Fernandez MAubut JAFoley N: Acute management of acquired brain injury part I: an evidence-based review of non-pharmacological interventions. Brain Inj 24:6947052010

  • 15

    Sahuquillo JArikan F: Decompressive craniectomy for the treatment of refractory high intracranial pressure in traumatic brain injury. Cochrane Database Syst Rev 1:CD0039832006

  • 16

    Schorl M: Sinking skin flap syndrome (SSFS)—clinical spectrum and impact on rehabilitation. Cent Eur Neurosurg 70:68722009

  • 17

    Schwab SSteiner TAschoff ASchwarz SSteiner HHJansen O: Early hemicraniectomy in patients with complete middle cerebral artery infarction. Stroke 29:188818931998

  • 18

    Segal DHOppenheim JSMurovic JA: Neurological recovery after cranioplasty. Neurosurgery 34:7297311994

  • 19

    Shoakazemi AFlannery TMcConnell RS: Long-term outcome of subcutaneously preserved autologous cranioplasty. Neurosurgery 65:5055102009

  • 20

    Stephens FLMossop CMBell RSTigno T JrRosner MKKumar A: Cranioplasty complications following wartime decompressive craniectomy. Neurosurg Focus 28:5E32010

  • 21

    Stiver SI: Complications of decompressive craniectomy for traumatic brain injury. Neurosurg Focus 26:6E72009

  • 22

    Waziri AFusco DMayer SAMcKhann GM IIConnolly ES Jr: Postoperative hydrocephalus in patients undergoing decompressive hemicraniectomy for ischemic or hemorrhagic stroke. Neurosurgery 61:4894942007

  • 23

    Yamaura ASato MMeguro KNakamura TUemura K: [Cranioplasty following decompressive craniectomy—analysis of 300 cases (author's transl).]. No Shinkei Geka 5:3453531977. (Jpn)


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