Article
Development of aseptic bone flap necrosis after autologous cranioplasty based on CT-scan analysis
Entwicklung der aseptischen Knochennekrose nach autologer Kranioplastik anhand einer computertomographisch-basierten Analyse
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Authors
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Sophie Kubon
- Universitätsklinikum Jena, Klinik und Poliklinik für Neurochirurgie, Jena, Deutschland
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Christian Senft
- Universitätsklinikum Jena, Klinik und Poliklinik für Neurochirurgie, Jena, Deutschland
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Falko Schwarz
- Universitätsklinikum Jena, Klinik und Poliklinik für Neurochirurgie, Jena, Deutschland
| Published: | June 4, 2021 |
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Outline
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Objective: Aseptic bone necrosis is still a common long-term complication after bone flap reinsertion following initial decompressive craniectomy. Aim of the study was to monitor the structural changes of the bone flap after cranioplasty as well as to determine the impact of an additional liquor shunt.
Methods: Thirty-four (22 male, 12 female) patients, who received a cranioplasty between September 2004 and April 2010, have been included. The medium age was 47 years at the time of cranioplasty. Reasons for the initial craniectomy were a subarachnoid haemorrhage (n = 10), a subdural or epidural haemorrhage (n = 11), a malignant cerebral infarction (n = 11) and an intracerebral haemorrhage (n=2).
We retrospectively analysed the first post-operative and follow-up CT scans and measured the bone density in Hounsfield units (HU), bone thickness (measurement at different defined points), the development of a bone bridge and a modification of the Lakshmanan score based on the trabecular pattern (Figure 1 [Fig. 1]). The median follow-up was 44 months.
Results: A significant loss of bone density with an average decline of 22.5 % (p<0.001) occurred in 29 patients (85.3%). Decline of bone density within the first 6 months was statistically relevant with a mean decrease from 1066 HU to 900 HU (p<0.001). 31 patients (91.2%) had a decrease in the bone thickness with an average loss of 1,62 mm. A decrease of the trabecular pattern was noticed in 24 (70.6%) patients. In 12 cases (35.3 %; 6 with shunt (17.7%), 6 without (17.7%) a surgery caused by the aseptic necrosis was indicated. Patients with a ventriculoperitoneal shunt (WS) had a slightly higher bone density than those without shunt (WOS), (WS: 886.07 HU; WOS: 800.84 HU, p = 0.488).
Conclusion: Decline in bone density and bone thickness were common observations in this study. The decrease seems to be relevant especially in the first 6 months. For this reason, patients should be monitored particularly closely during this time. Further patients should be analysed to investigate, whether there is a significant difference between patients with or without a ventriculoperitoneal shunt.
