Bone Flap Changes after Cranioplasty Using Frozen Autologous Bone Flaps: A Three-Dimensional Volumetric Reconstruction Study

Abstract

PurposeBone flap resorption (BFR) after cranioplasty with an autologous bone flap (ABF) is well known. However, the prevalences and degrees of BFR remain unclear. This study aimed to evaluate changes in ABFs following cranioplasty and to investigate factors related with BFR.Materials and MethodsWe retrospectively reviewed 97 patients who underwent cranioplasty with frozen ABF between January 2007 and December 2016. Brain CT images of these patients were reconstructed to form three-dimensional (3D) images, and 3D images of ABF were separated using medical image editing software. ABF volumes on images were measured using 3D image editing software and were compared between images in the immediate postoperative period and at postoperative 12 months. Risk factors related with BFR were also analyzed.ResultsThe volumes of bone flaps calculated from CT images immediately after cranioplasty ranged from 55.3 cm3 to 175 cm3. Remnant bone flap volumes at postoperative 12 months ranged from 14.2% to 102.5% of the original volume. Seventy-five patients (77.3%) had a BFR rate exceeding 10% at 12 months after cranioplasty, and 26 patients (26.8%) presented severe BFR over 40%. Ten patients (10.3%) underwent repeated cranioplasty due to severe BFR. The use of a 5-mm burr for central tack-up sutures was significantly associated with BFR (p<0.001).ConclusionMost ABFs after cranioplasty are absorbed. Thus, when using frozen ABF, patients should be adequately informed. To prevent BFR, making holes must be kept to a minimum during ABF grafting.

Cranioplasty with Autologous Bone Flaps Cryopreserved with Dimethylsulphoxide: Does Tissue Processing Matter

“…In a recent study, using 3D image analysis system, different grades of BFR have been observed in 77% of patients. 20 Our overall rate of BFR (26.1%) can be considered as an intermediate level, compared to the limits of the range provided by literature on this subject (2.5% to 50%). In our study, the only significant factor associated with this complication was early cranioplasty, which represented 13/16 cases (81.2%) (table 2).…”

Explanted Skull Flaps after Decompressive Hemicraniectomy Demonstrate Relevant Bone Avitality-Is Their Reimplantation Worth the Risk?

“…BFR, which is also called aseptic bone necrosis or osteonecrosis, has been long recognized as the most common ABF-specific cranioplasty complication with an estimated pooled incidence of 15% to almost every second patient, according to recently published clinical systematic reviews [ 3 , 4 , 6 , 8 ]. Further specific volumetric studies on ABFs identified much higher rates of BFR, namely from 77 to 90% [ 9 , 10 ]. Spake et al reported a rate of 82% for clinically relevant BRF depicted on cranial CT among their cohort, whereas BRF progressed over the years in a linear and continuous manner [ 11 ].…”

Load-Bearing Capacity and Design Advantages of a Custom-Made, Thin Pure-Titanium Cranioplasty (CranioTop)

“…6 However, the problem of bone resorption due to the lack of nutrition must be considered; in almost one-third of cases, this leads to conspicuous contour irregularities and unsatisfactory cosmetic results and, in extreme cases, loss of the implanted bone. 7,8 Cranioplasty with PMMA is similarly cost-effective and can be manufactured to properly cover the bone defect. 3 However, some authors have found that PMMA cranioplasties cause slightly more complications 9 and significantly higher infection rates.…”

“…The treatment of skull defects with the autologous bone flap is one of the methods employed in everyday neurosurgical practice 6 . However, the problem of bone resorption due to the lack of nutrition must be considered; in almost one-third of cases, this leads to conspicuous contour irregularities and unsatisfactory cosmetic results and, in extreme cases, loss of the implanted bone 7,8 . Cranioplasty with PMMA is similarly cost-effective and can be manufactured to properly cover the bone defect 3 .…”