What happens to the bone flap? Long-term outcome after reimplantation of cryoconserved bone flaps in a consecutive series of 92 patients

Abstract

BACKGROUND: Reimplantation of cryoconserved autologous bone flaps is a standard procedure after decompressive craniotomies. Aseptic necrosis and resorption are the most frequent complications of this procedure. At present there is no consensus regarding the definition of the relevant extent and indication for surgical revision. The objective of this retrospective analysis was to identify the incidence of bone flap resorption and the optimal duration of follow-up. METHODS: Between February 2009 and March 2012, 100 cryoconserved autologous bone flaps were reimplanted at the Department of Neurosurgery, Inselspital Bern. Three patients were not available for follow-up, and five patients died before follow-up. All patients underwent follow-up at 6 weeks and a second follow-up more than 12 months postoperatively. A clinical and CT-based score was developed for judgment of relevance and decision making for surgical revision. RESULTS: Mean follow-up period was 21.6 months postoperatively (range: 12 to 47 months); 48.9 % (45/92) of patients showed no signs of bone flap resorption, 20.7 % (19/92) showed minor resorption with no need for surgical revision, and 30.4 % (28/92) showed major resorption (in 4 % of these the bone flap was unstable or collapsed). CONCLUSIONS: Aseptic necrosis and resorption of reimplanted autologous bone flaps occurred more frequently in our series of patients than in most reports in the literature. Most cases were identified between 6 and 12 months postoperatively. Clinical observation or CT scans of patients with autologous bone flaps are recommended for at least 12 months. Patient-specific implants may be preferable to autologous bone flaps. This work has not been previously presented in part or in whole, and has not been concurrently submitted elsewhere.Disclosure of funding: The authors have declared no competing interests. The providers of the software had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No specific funding was provided for this work. 2 ABSTRACTBackground: Reimplantation of cryoconserved autologous bone flaps is a standard

A randomized controlled trial comparing autologous cranioplasty with custom-made titanium cranioplasty

“…11,13,24 This trial has also confirmed that the cranioplasty procedure is not without significant complications, although the very low rate of primary infections requires further consideration.…”

“…16 There will always be some degree of subjectivity when making these types of assessments, although for those bone flaps that were deemed to be a complete failure, there was little doubt that cranial protection was compromised. However, as noted by Stieglitz et al, 24 a number of patients with significant resorption did not spontaneously report this occurrence and were unaware that there was a potential problem. This highlights the need for longterm clinical and radiological surveillance, especially in young adults.…”

Cranioplasty: morbidity and failure

“…11,12 The procedure itself is technically straightforward, however it is becoming increasingly apparent that it is associated with relatively high morbidity and a significant failure rate due to either infection or autologous bone flap resorption. [13][14][15][16][17][18][19][20] When this 'failure' occurs further surgery is required in order to remove the primary cranioplasty and either commence antibiotics with a view to performing a delayed secondary reconstruction or replace the resorbed autologous bone with a secondary titanium cranioplasty.…”

Cryopreservation Versus Intracorporeal Preservation of Cranial Bone Flaps; A Comprehensive Review of Literature

“…Also, the fragmented bone flaps or those implanted in patients undergone Ventriculo-peritoneal shunts showed a higher incidence of bone resorption causing bone flap collapse. 11 In a retrospective analysis by LH Stieglitz et al 15 100 patients were reimplanted with a cryopreserved autologous bone flap. Out of…”

“…17 The incidence of complication is linked to patients age in many cases and is more frequent in children than adults. 15 Intracorporeal preservation is a way of preserving cranial bone flaps. The flaps are stored in subcutaneous pouches in the abdominal wall.…”