Autogenous Bone Flaps Research Articles

Accurate Reconstruction of Mandibular Defects With Vascularized Bone Flaps Through Utilization of Mandible Space-Retention Guides.

Comprehensive evaluation of the effects of using computer-aided design and space retention guide technology to reconstruct mandibular defects using vascularized autogenous bone flaps. This study included 8 patients who received autogenous bone flaps (2 cases of vascularized fibula flaps and 6 cases of vascularized iliac flaps) for mandibular defect reconstruction at Peking University School and Hospital of Stomatology, from July 2018 to May 2021. All patients received digital surgery planning, computer aided design/computer aided manufacture, surgical guide technique for the removal of diseased bone segments, as well as vascularized fibular flap/iliac flap reconstruction. Three-dimensional deviations were analyzed after the operation. The mandibular defects of all 8 patients were successfully reconstructed using the vascularized fibular flap/iliac bone flap. There were no serious complications at either the donor site or recipient site during our follow-up. The average three-dimensional deviation of all 8 patients was 1.92 mm, based on comparisons of preoperative design and actual postoperative computed tomography. Utilizing computer aided design/computer aided manufacture, we designed a new mandibular space-retention guide, which can accurately translate the preoperative digital design plan to real-time surgery with satisfactory accuracy and efficacy.

Cranioplasty With Autogenous Frozen and Autoclaved Bone: Management and Treatment Outcomes.

Cranioplasty is a widely employed procedure for restoration of calvarial form and shape. The use of autogenous bone flap offers biological reconstruction with minimal donor site morbidity. One of the options to re-use bone autograft is low temperature preservation followed by autoclaving during cranioplasty. A retrospective evaluation of 12 patients with a mean age of 32.58 ± 10.04 years who underwent frozen autogenous autoclaved bone cranioplasty was done. Cranial bone flaps were removed during the initial craniectomy and stored at 4°C for 20 minutes followed by preservation at -40°C in the deep freezer of the blood bank. Cranioplasty subsequently was performed at a mean time period of 172.17 ± 26.20 days by thawing the bone at room temperature followed by autoclaving at 121°C under 15 psi for 40 minutes. Data regarding patients' characteristics and complications were recorded. Clinical outcomes based on skull shape and symmetry, cosmesis and scars were analyzed by a panel of 4 raters, including 3 doctors and 1 patient. Radiological outcomes were analyzed based on remaining bone thickness and bone gap widening. The present study revealed functionally, structurally, and cosmetically satisfying results. All the cases had satisfactory healing and no incidence of bone graft infection. The skull shape and symmetry, cosmesis and scars revealed excellent to moderate improvement in three-fourth of the patients. Radiological outcomes revealed none of the patients had severe resorption requiring surgical revision with excellent to good implant alignment in 92% of cases. It was concluded that frozen autogenous cranial bone flaps sterilized by autoclaving is safe and effective material for cranioplasty.

Adult Cranioplasty

After reading this article, the participant should be able to: Understand the etiology of cranial defects. Understand the anatomy of the cranium. Understand the importance of the preoperative workup in the cranial reconstruction decision-making process. Describe the options available for calvarial reconstruction including autologous and alloplastic materials. Describe the basic differences between available alloplastic materials. Understand the intraoperative and postoperative complications that may arise during cranioplasty. Cranial defects can arise from a variety of causes, yielding a diverse group of patients who require cranioplasty. The goals of calvarial reconstruction are to protect the underlying brain, to restore the aesthetic contour of the calvarium, and/or to treat postcraniectomy cerebrospinal fluid circulation abnormalities that may be symptomatic. Options for calvarial reconstruction include the autogenous bone flap that was removed for access, autologous bone grafting, and a variety of alloplastic materials such as titanium, hydroxyapatite, polymethylmethacrylate, polyether ether ketone, and high-density porous polyethylene. A detailed preoperative workup and discussion with the patient is important to choosing the appropriate reconstructive path.

Extensive eggshell-like debridement technique plus antibiotic-loaded calcium sulphate for one-stage treatment of chronic calcaneal osteomyelitis

BackgroundManagement of chronic calcaneal osteomyelitis is challenging. At present, there is still no widely accepted, simple, and effective surgical method to eradicate the infection and prevent osteomyelitis recurrence. The objective of this study was to assess the outcomes of one-stage treatment of chronic calcaneal osteomyelitis with a shape-preserving debridement technique combined with antibiotic-loaded calcium sulphate. MethodsBetween 2012 and 2018, 33 patients (33 limbs) with chronic calcaneal osteomyelitis were treated with a novel debridement technique, named “eggshell-like debridement”, plus antibiotic-impregnated calcium sulphate. The infection remission rate, recurrence rate, and amputation rate were analyzed. The American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot score was used to assess postoperative hindfoot function. Results26 patients (81.8%) achieved infection remission without recurrence. In the patients with osteomyelitis remission, pain, limitation of movement, sinus tracts, and typical redness and swelling were generally eliminated. Most of the patients could tolerate full weight-bearing without pain. The average AOFAS ankle and hindfoot score was 88 points (range, 67–100 points), implying the foot function was mostly restored. 6 patients (18.2%) had osteomyelitis recurrence but no amputation was required to elimilate the infection. ConclusionsEggshell-like debridement combined with antibiotic-loaded calcium sulphate is an effective method for one-stage management of chronic calcaneal osteomyelitis. With the application of this technique, secondary autogenous bone or muscle flap grafts are unnecessary. The surgical procedure can be simplified whlie the hindfoot function is well preserved.

Cryopreservation of Autologous Cranial Bone Flaps for Cranioplasty: A Large Sample Retrospective Study.

To clarify the clinical outcomes of cranioplasty with cryopreserved bone flaps and identify risk factors related to bone flap infection and resorption after cranioplasty with cryopreserved bone flaps. A total of 946 patients (989 bone flaps) underwent decompressive craniectomy and delayed cranioplasty via the use of cryopreserved autogenous cranial bone flaps. Cranial bone flaps were removed during the initial craniectomy and reserved in liquid nitrogen (-196°C) with dimethyl sulfoxide as a cryoprotectant. Cranioplasty subsequently was performed once the brain injury had healed. Data regarding complications and clinical outcomes were recorded and the potential risk factors were analyzed. Data from 960 flaps were available for analysis. The overall complication rate was 15.83% (152 of 960). Bone resorption occurred in 42 flaps in 37 patients (4.38%). The bone flaps resorption rate was greater in patients ≤18 years than in patients >18 years (9.38% vs. 3.61%, P < 0.05). Cryopreservation for more than 365 days tended to result in a greater bone resorption rate (6.88% vs. 2.92%, P < 0.01). Skull bone grafts infection occurred in 39 flaps in 34 patients (4.06%). The bone graft infection rate was greater in emergency craniectomy cases (8.81% vs. 2.59%, P < 0.01) and in patients with diabetes (10.53% vs. 3.07%, P < 0.01). Cryopreservation of autologous cranial bone flaps is safe and effective for cranioplasty. Cranioplasty with cryopreserved autologous cranial bone flaps should be performed no more than 1 year after craniectomy. Emergency craniectomy and patients with diabetes require special attention.

Cranioplasty with autogenous bone flaps cryopreserved in povidone iodine: a long-term follow-up study.

OBJECTIVE The aim of this study was to investigate the long-term therapeutic efficacy of cranioplasty with autogenous bone flaps cryopreserved in povidone iodine and explore the risk factors for bone resorption. METHODS Clinical data and follow-up results of 188 patients (with 211 bone flaps) who underwent cranioplasty with autogenous bone flaps cryopreserved in povidone-iodine were retrospectively analyzed. Bone flap resorption was classified into 3 types according to CT features, including bone flap thinning (Type I), reduced bone density (Type II), and osteolysis within the flaps (Type III). The extent of bone flap resorption was graded as mild, moderate, or severe. RESULTS Short-term postoperative complications included subcutaneous or extradural seroma collection in 19 flaps (9.0%), epidural hematoma in 16 flaps (7.6%), and infection in 8 flaps (3.8%). Eight patients whose flaps became infected and had to be removed and 2 patients who died within 2 years were excluded from the follow-up analysis. For the remaining 178 patients and 201 flaps, the follow-up duration was 24-122 months (mean 63.1 months). In 93 (46.3%) of these 201 flaps, CT demonstrated bone resorption, which was classified as Type I in 55 flaps (59.1%), Type II in 11 (11.8%), and Type III in 27 (29.0%). The severity of bone resorption was graded as follows: no bone resorption in 108 (53.7%) of 201 flaps, mild resorption in 66 (32.8%), moderate resorption in 15 (7.5%), and severe resorption in 12 (6.0%). The incidence of moderate or severe resorption was higher in Type III than in Type I (p = 0.0008). The grading of bone flap resorption was associated with the locations of bone flaps (p = 0.0210) and fragmentation (flaps broken into 2 or 3 fragments) (p = 0.0009). The incidence of bone flap collapse due to bone resorption was higher in patients who underwent ventriculoperitoneal (VP) shunt implantation than in those who did not (p = 0.0091). CONCLUSIONS Because of the low incidence rates of infection and severe bone resorption, the authors conclude that cranioplasty with autogenous bone flaps cryopreserved in povidone-iodine solution is safe and effective. The changes characteristic of bone flap resorption became visible on CT scans about 2 months after cranioplasty and tended to stabilize at about 18 months postoperatively. The bone resorption of autogenous bone flap may be classified into 3 types. The rates of moderate and severe resorption were much higher in Type III than in Type I. The grade of bone flap resorption was associated with bone flap locations. Fragmented bone flaps or those implanted in patients treated with VP shunts may have a higher incidence of bone flap collapse due to bone resorption.

Autologous Skull Bone Flap Sterilization After Decompressive Craniectomy: An Update

To report new results with ethylene oxide sterilization and new experiences with autogenous bone flaps autoclaved at a high or low temperature for preservation of a bone flap after decompressive craniectomy. In 45 patients who underwent a decompressive craniectomy, we determined bone flap preservation with ethylene oxide and with high- or low-temperature autoclave sterilization. The bone flap was repositioned after a mean of 10 weeks in the ethylene oxide group and after 6 weeks in the other sterilization groups. A bone flap infection developed in 1 patient (2%), which required removal and subsequent methyl methacrylate cranioplasty. In 1 child, the bone flap had partially reabsorbed after 12 months. In all other patients, esthetic results were good after an average follow-up of 42 months. At follow-up, computed tomography or magnetic resonance imaging of the bone flap showed preservation of structural features with apparent fusion and revitalization at the bone flap margins. Ethylene oxide and high- or low-temperature autoclave bone sterilization techniques for the preservation of autologous bone flaps after decompressive craniectomy were safe, rapid, and inexpensive.

Microbial contamination assessment of cryostored autogenous cranial bone flaps: should bone biopsies or swabs be performed?

Autogenous cranioplasty infection requiring bone flap removal is under-recognised as a major complication causing significant morbidity. Microbial contamination of stored bone flaps may be a significant contributing factor. Current infection control practices and storage procedures vary. It is not known whether 'superficial' swabs or bone cultures provide a more accurate assessment. Twenty-five skull flaps that were cryo-stored for more than 6months were studied. Two swab samples (superficial and deep) and a bone biopsy sample were taken from each skull flap sample and cultured. Half blood agar and half chocolate agar plates were inoculated with the swabs for anaerobic and aerobic cultures respectively. The bone biopsy samples were cultured in brain-heart broth and subcultured similar to the swabs for 5days. Incidence of microbial contamination was 20% in the bone flaps studied. One swab culture and five bone biopsy cultures were positive for bacterial growth, all of which contained Propionibacterium acnes (p = 0.014). Positive cultures were from bone flaps stored less than 18months, whereas no growth was obtained from bone flaps that were stored longer (p = 0.014). Bone biopsy culture is a more sensitive technique of assessing microbial contamination of cryo-stored autogenous bone flaps than swab cultures. The clinical implications of in vitro demonstration of microbial contamination require further study.

Bone flap storage following craniectomy: a survey of practices in major Australian Neurosurgical centres

The resurgence of decompressive craniectomy surgeries for management of intracranial hypertension has led to a parallel increase in cranioplasty procedures for subsequent reconstruction of the resultant extensive skull defects. Most commonly, cranioplasties are performed using the patients' own cryopreserved skull flaps. Currently, there are no standardized guidelines for freeze-storage of bone flaps either nationally or internationally. In this initial study, the authors surveyed major neurosurgical centres throughout Australia to document current clinical practices. Twenty-five neurosurgical centres affiliated with major public, teaching hospitals in all Australian states were included in the current survey study. A standardized survey guide incorporating standardized questions was used for data collection either by phone interviews and/or electronic (email) communication. Details regarding bone flap preparation following craniectomy, temperature and duration of freeze-storage, infection control/micro-contamination detection protocols, pre-implantation procedures were specifically recorded. Cranioplasty using cyropreserved autogenous bone flaps remains the most common (96%) mode of skull defect reconstruction in major neurosurgical centres throughout Australia. Following the initial craniotomy, the harvested skull flaps were most frequently (88%) double- or triple-bagged under dry, sterile conditions. In 16% of hospitals, skull flaps were irrigated either with antibiotic mixed-saline or Betadine prior to cryopreservation. Skull biopsies or swabs were obtained from the skull flaps for micro-contamination studies in accordance with departmental protocol in 68% of hospitals surveyed. Subsequently, the bone flaps were cryopreserved at wide ranging temperatures between -18°C to -83°C, for variable time intervals (6 months to 'until patient deceased'). Twelve neurosurgical centres (48%) elected for bone flap storage to be undertaken at the local bone bank. In the remainder (52%) of the hospitals, bone flaps were cryopreserved in locally maintained freezers. Prior to re-implantation of the skull flaps at subsequent cranioplasty surgeries, six (24%) of the neurosurgical centres had specific thawing procedures involving immersion of the frozen bone flaps in Ringer's solution and/or Betadine. Further pre-implantation bacteriological cultures from bone biopsies or swabs were obtained only in three (12%) hospitals. This study has documented highly varied skull flap cryopreservation and storage practices in neurosurgical centres throughout Australia. These differences may contribute to relatively high complication rates of infection and bone resorption reported in the literature. The results of the current study argue for the further need of high quality clinical and basic science research, which aims to characterize the effect of current skull flap management practices and freeze-storage conditions on the biological and biomechanical properties of skull bone.

Do cryopreserved autogenous cranial bone flaps remain viable at cranioplasty?

Do cryopreserved autogenous cranial bone flaps remain viable at cranioplasty?

The biological changes of autogenous skull flap after subcutaneous preservation and early cranioplasty

Objective To investigate the biological changes of autogenous skull flap after subcutaneous preservation and early cranioplasty.Methods The New Zealand white rabbits were divided into 3 groups:normal controls,sham-operated controls and operated groups,and the models of skull flap-removed decompression and subcutaneous preservation were established.The autogenous eamioplasty was clone two weeks after sabeutaneous preservation.The calcium content of skull flap was deterrainated at different time points,and histological and bio-structural changes were observed by using immunohistochemistry stain and electron microscopy scanning.Results The calcium contents in normal and subcutaneously preserved skull flaps were(935.15±166.36)(normal),(847.40±126.97)(at first week),(766.55±126.89)(at 2nd week),(603.53±37.10)(at 4th week),and(444.68±48.05)μg/g(at 8th week)respectively.The calcium contents in the skull flaps after carnioplaty were(628.53±47.16)(at 2nd week),(691.55± 50.61)(at 4th week),and(835.89± 94.75)μg/g(at 8th week)respectively.The skull flaps subcutaneously preserved were wrapped up by fibrous tissue gradually,the marrow cavity was destroyed,and the lacunar ceils in the osseous lamella were dead,but the bone trabecula still existed.After the transplantation of the autogenous skull flap,blood vessels were grown into the bone edges as the time went on,and part of the dead bone reactivated.Conclusion The autogenous skull flap cranioplasy sbould be clone at the 4th week after subcutaneous preservation.If the autogenous skull flap eranioplasy could be done early,the biochemical characters of the skull flaps which preserved subcutaneously could achieve almost normal leve]. Key words: Autogenous bone flap; Cranial bone forming operation; Bone biology

Assessment of the effects on growth of porous hydroxyapatite granule cranioplasty in the immature guinea pig craniofacial skeleton.

The immature guinea pig was used to study the effects on growth of porous granular hydroxyapatite used as an onlay cranioplasty and inlay cranioplasty to reconstruct full-thickness cranial defects in a growing craniofacial skeleton. Forty Hartley guinea pigs, 20 immature animals and 20 mature animals, were divided into four groups each containing five mature and five immature animals. The mature animals served as controls. Group I underwent elevation and replacement of the parietal periosteum. Group II underwent placement of hydroxyapatite between periosteum and parietal bone. Group III underwent elevation and replacement of autogenous bone flap after the formation of a 1 x 1-cm craniectomy defect in the parietal skull. Group IV underwent elevation of a 1 x 1-cm parietal craniectomy and reconstruction of the defect with hydroxyapatite granules placed between the dura and periosteum. Immature animals were killed at maturity at 3.5 months and mature animals were killed 2.5 months postoperatively. Macroscopic examination of the operative field, transverse and longitudinal cephalometric measurements, and histological sections encompassing the operative sites were compared. Macroscopically, all reconstructed operative sites were fully incorporated into the cranium. Histological staining of the sectioned operative site revealed no hydroxyapatite migration through the cranial bone or dura. No inflammatory or foreign body reaction was evident in the subcutaneous tissue, periosteum, or dura. No statistically significant cephalometric intergroup or intragroup differences were found at the conclusion of the study. The results of this study indicate that a granular porous form of hydroxyapatite may be used as an onlay or inlay cranioplasty in the immature guinea pig craniofacial skeleton without evidence of dural inflammation, granule migration, or growth restriction or retardation.

The use of frozen autogenous bone flaps in delayed cranioplasty revisited.

To reevaluate the use of frozen autogenous bone flaps for patients undergoing delayed cranioplasty. In the past 12 years, 49 patients have undergone delayed cranioplasty using frozen autogenous bone flaps. Bone flaps removed during the initial operation were sealed in three sterilized vinyl bags and stored at -35 degrees C (n = 37) or -84 degrees C (n = 12) for 4 to 168 days (mean, 50.6 d). The bone flaps were thawed at room temperature and replaced in their original positions. After cranioplasty, we monitored resorption of the bone flaps with computed tomography and evaluated the clinical and aesthetic results. Follow-up periods ranged from 14 to 147 months (mean, 59.2 mo). For 47 patients (95.9%), there were no complications during the follow-up period; there was slight thinning of the bone flap in some cases, but clinical and aesthetic results were highly satisfactory. Resorption was observed for a 12-year-old boy who had undergone cranioplasty, using two pieces of bone flap, 66 days after the initial operation. A 14-year-old boy with a cerebral contusion experienced a bone flap infection. Both patients underwent a second cranioplasty procedure, with ceramic plates. The clinical and aesthetic results of delayed cranioplasty using frozen autogenous bone flaps were satisfactory. The most important factor for success was excellent contiguity between the flap and the bone edge.

冷凍保存自家骨による頭蓋形成術の検討 とくに超低温保存法５症例について

Skull restoration after decompressive craniectomy, in the past, employed primarily various plastics and metals. Autogenous calvaria have less often been preserved for delayed reimplantation. It is generally agreed that the autogenous bone flap would be superior to any artificial materials available if it could be used in cranioplasty. Therefore, we conducted cranioplasty in 5 cases using cryo-preserved autogenous bone. We assessed several factors, including histological changes, postoperative changes in skull morphology and the incidence of infection. Autogenous bone fragments removed aseptically at craniotomy were stored for 1 to 3 months at -85°C, an ultralow temperature, and returned to room temperature before use. We were able to follow-up the postoperative behavior of the transplanted bone roentgenographically. In addition, histopathological evaluations were conducted on bone flaps. In the roentgenographical observations, most cases showed mild bone resorption. In the histological deviations of the bone flaps, mild osteocyte changes were noted. No post-operative infections occurred. Therefore, we consider the method reported herein to be a simple procedure and cryo-preserved autogenous bone to be satisfactory for cranioplasty.

Cranioplasty with a frozen and autoclaved bone flap

27 cases of cranioplasty with autogenous bone grafts stored in a deep-freezer and autoclaved before use are reported. The results of follow-up for an average period of one year were satisfactory from the standpoint of brain protection and cosmetic reconstruction. A small area of absorption of grafted bone was observed in two cases on the follow-up skull roentgenograms. No serious complications were seen except in one case, whose bone flap had to be removed due to an epidural abscess. Experiments revealed that deep-freezing and autoclaving had only minimal effects on bone structure, although osteocytes degenerated. Autogenous bone flap after deep-freezing is a useful material for cranioplasty but sterilization before use is indispensable. Autoclaving is a simple method for sterilization of the flap, available in any operating theatre. It does not increase the risk of postoperative complications such as infection or absorption.

Cranioplasty utilizing a preserved autogenous bone flap coated with acrylic resin.

Cranioplasty utilizing a resin-coated preserved autogenous skull flap was devised and used in 36 cases, 14 of them being followed up radiologically. It has been confirmed that this method is advantageous in that it repairs the skull defect satisfactorily both from surgical and cosmetic points of view. Furthermore this method causes no anxiety to the patient because of the autogenous origin of the bone flap. We recommend this method for cranioplasty when an autogenous bone flap is preserved.

The use of refrigerated autogenous bone flaps for cranioplasty.

The use of refrigerated autogenous bone flaps for cranioplasty.