Skull Flap Research Articles

Dehydrated human amnion/chorion membrane use in emergent craniectomies shows minimal dural adhesions.

Decompressive craniectomies (DCs) are routinely performed neurosurgical procedures to emergently treat increased intracranial pressure secondary to multiple aetiologies, such as subdural haematoma, epidural haematoma, or malignant oedema in the setting of acute infarction. The DC procedure typically induces epidural fibrosis post-cranial resection, resulting in adherence of the dura to both the brain internally and skin flap externally. This becomes especially problematic in the setting of skull flap replacement for cranioplasty as adherences can lead to bridging vein tear, damage to the underlying brain cortex, and other postoperative complications. Dural adjuvants, which can contribute to decreased rate of adherence formation, can thereby reduce both postoperative cranioplasty complications and operative duration. Dehydrated human amnion/chorion membrane (DHACM) allografts (AMNIOFIX, MIMEDX Group Inc., US) have been shown to reduce the rate of dural scar tissue formation in re-exploration of posterior lumbar interbody fusion operations which require entry into the epidural space. The purpose of this study was to evaluate whether or not the use of DHACM in the setting of emergent craniectomies decreased the rate of dural adhesion formation and subsequent cranioplasty complications. Patients (n=7) who underwent emergent craniectomy and intraoperative placement of DHACM were evaluated during replacement of either an autologous skull cap or a custom-made implant, at which point the degree of adhesions was qualitatively assessed. Placement of DHACM below and on top of the dura resulted in negligible adhesion being found during the defect exposure, and there were no intraoperative complications during cranioplasties. Reported estimated blood loss across the seven patients averaged 64.2ml, total operative time averaged 79.2 minutes, and time dedicated to exposing defect for bone flap placement was <3 minutes.

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

Reimplantations of autologous skull flaps after decompressive hemicraniectomies (DHs) are associated with high rates of postoperative bone flap resorption (BFR). We histologically assessed the cell viability of explanted bone flaps in certain periods of time after DH, in order to conclude whether precursors of BRF may be developed during their storage. Skull bone flaps explanted during a DH between 2019 and 2020 were stored in a freezer at either -23 °C or -80 °C. After their thawing process, the skulls were collected. Parameters of bone metabolism, namely PTH1 and OPG, were analyzed via immunohistochemistry. H&E stain was used to assess the degree of avital bone tissue, whereas the repeated assays were performed after 6 months. A total of 17 stored skull flaps (8 at -23 °C; 9 at -80 °C) were analyzed. The duration of cryopreservation varied between 2 and 17 months. A relevant degree of bone avitality was observed in all skull flaps, which significantly increased at the repeated evaluation after 6 months (p < 0.001). Preservation at -23 °C (p = 0.006) as well as longer storage times (p < 0.001) were identified as prognostic factors for higher rates of bone avitality in a linear mixed regression model. Our novel finding shows a clear benefit from storage at -80° C, which should be carefully considered for the future management and storage of explanted skull flaps. Our analysis also further revealed a significant degree of bone avitality, a potential precursor of BFR, in skull flaps stored for several weeks. To this end, we should reconsider whether the reimplantation of autologous skull flaps instead of synthetic skull flaps is still justified.

Skull defect increases the tumor treating fields strength without detrimental thermogenic effect: A computational simulating research.

Tumor treating fields (TTFields) is an FDA-approved adjuvant therapy for glioblastoma. The distribution of an applied electric field has been shown to be governed by distinct tissue structures and electrical conductivity. Of all the tissues the skull plays a significant role in modifying the distribution of the electric field due to its large impedance. In this study, we studied how remodeling of the skull would affect the therapeutic outcome of TTFields, using a computational approach. Head models were created from the head template ICBM152 and five realistic head models. The electric field distribution was simulated using the default TTFields array layout. To study the impact of the skull on the electric field, we compared three cases, namely, intact skull, defective skull, and insulating process, wherein a thin electrical insulating layer was added between the transducer and the hydrogel. The electric field strength and heating power were calculated using the FEM (finite element method). Removing the skull flap increased the average field strength at the tumor site, without increasing the field strength of "brain". The ATVs of the supratentorial tumors were enhanced significantly. Meanwhile, the heating power of the gels increased, especially those overlapping the skull defect site. Insulation lightly decreased the electric field strength and significantly decreased the heating power in deep tumor models. Our simulation results showed that a skull defect was beneficial for superficial tumors but had an adverse effect on deep tumors. Skull removal should be considered as an optional approach in future TTFields therapy to enhance its efficacy. An insulation process could be used as a joint option to reduce the thermogenic effect of skull defect. If excessive increase in heating power is observed in certain patients, insulating material could be used to mitigate overheating without sacrificing the therapeutic effect of TTFields.

Explanted skull flaps after decompressive hemicraniectomy demonstrate increased bone avitality. Is the reimplantation of autologous skulls still justified?

Explanted skull flaps after decompressive hemicraniectomy demonstrate increased bone avitality. Is the reimplantation of autologous skulls still justified?

Predictive Value of Swab Cultures for Cryopreserved Flaps During Delayed Cranioplasties

To assess the predictive value of swab cultures of cryopreserved skull flaps during cranioplasties for surgical site infections (SSIs). A retrospective review was conducted of consecutive patients who underwent delayed cranioplasties with cryopreserved autografts between 2009 and 2017. The results of cultures obtained from swabs and infected surgical sites were assessed. The accuracy, sensitivity, and specificity of swab cultures for SSIs were evaluated. The study included 422 patients categorized into two groups, swab and nonswab, depending on whether swab cultures were implemented during cranioplasties. The overall infection rate was 7.58%. No difference was seen in infection rates between groups. There were 18 false-positive and no true-positive swab culture results. All bacteria between swab cultures and SSI cultures were discordant. Meanwhile, there were 19 false-negative swab cultures. The results showed high specificity but low sensitivity for swab cultures to predict SSI occurrence and the pathogens. Owing to low accuracy and sensitivity, swab cultures of cryopreserved autografts should not be routinely performed during delayed cranioplasties.

Study on infection potential of explanted different cryostored skull flaps. Is storage at -80 °C better?

Study on infection potential of explanted different cryostored skull flaps. Is storage at -80 °C better?

Decompressive Craniectomy for Traumatic Brain Injury: In-hospital Mortality-Associated Factors.

Objective Determine predictors of in-hospital mortality in patients with severe traumatic brain injury (TBI) who underwent decompressive craniectomy. Materials and Methods This retrospective study reviewed consecutive patients who underwent a decompressive craniectomy between March 2017 and March 2020 at our institution, and analyzed clinical characteristics, brain tomographic images, surgical details and morbimortality associated with this procedure. Results Thirty-three (30 unilateral and 3 bifrontal) decompressive craniectomies were performed, of which 27 patients were male (81.8%). The mean age was 52.18 years, the mean Glasgow coma scale (GCS) score at admission was 9, and 24 patients had anisocoria (72.7%). Falls were the principal cause of the trauma (51.5%), the mean anterior–posterior diameter (APD) of the bone flap in unilateral cases was 106.81 mm (standard deviation [SD] 20.42) and 16 patients (53.3%) underwent a right-sided hemicraniectomy. The temporal bone enlargement was done in 20 cases (66.7%), the mean time of surgery was 2 hours and 27 minutes, the skull flap was preserved in the subcutaneous layer in 29 cases (87.8%), the mean of blood loss was 636.36 mL,and in-hospital mortality was 12%. Univariate analysis found differences between the APD diameter (120.3 mm vs. 85.3 mm; p = 0.003) and the presence of midline shift > 5 mm ( p = 0.033). Conclusion The size of the skull flap and the presence of midline shift > 5 mm were predictors of mortality. In the absence of intercranial pressure (ICP) monitoring, clinical and radiological criteria are mandatory to perform a decompressive craniectomy.

Surgical Treatment of Tensile Effusion in Postoperative Cavity after Glioma Resection

Objectives: To explore the clinical surgical methods for the treatment of tensile effusion in postoperative cavity after glioma resection. Methods: Clinical data of 26 cases of tensile effusion in postoperative cavity after glioma resection were analyzed retrospectively. All 26 patients underwent surgical treatment, including 16 cases who underwent puncture and drainage (P&amp;D), and 10 cases who underwent craniotomy decompression (CD). Among the cases of P&amp;D, postoperative cavity in 7 cases were punctured through the burr hole for creating the skull flap for intraoperative resection of glioma, and postoperative cavities in 9 cases were punctured through a burr hole for the dura mater suspended under the skull flap. Glasgow Coma Scale (GCS) was used to evaluate the consciousness status of the two groups of patients before and after surgery. Moreover, time of operation, intraoperative blood loss, postoperative hospital duration, and postoperative complications were also adopted for evaluation of the merits of the two methods for treatment of tensile effusion in postoperative cavity after glioma resection. Results: The consciousness of the patients in both groups improved within 24 hours after the operation, and there were no death cases. In the P&amp;D group, the GCS score within 24 hours after surgery was (14.38±0.20), the time of operation time was (7.81±0.64) mins, intraoperative blood loss was (6.25±0.56) ml, and postoperative hospital duration was (6.69±0.54) days. There were 3 cases with postoperative complications (1 case of puncture tract hemorrhage, 1 case of subdural hematoma and 1 case of intracranial infection) in the P&amp;D group. All of the puncture tract hemorrhage and subdural hematoma did not require surgical treatment, and the intracranial infection was cured after antibiotic treatment and lumbar puncture for cerebrospinal fluid replacement. In the CD group, the GCS score within 24 hours after surgery was (13.70±0.21), the time of operation was (124.10±8.96) mins, intraoperative blood loss was (260±30.55) ml, and postoperative hospital duration was (11.30±0.60) days. There were 2 cases with postoperative complications (both of them were with subdural hematoma), none of which required surgical treatment. The GCS score, time of operation, intraoperative blood loss and postoperative hospital duration in the P&amp;D group were better than those in the CD group (P &lt; 0.05). There was no significant difference in the incidence of postoperative complications between the two groups (P &gt;0.05). Conclusion: The P&amp;D and CD for tensile effusion in postoperative cavity after glioma resection can both achieve ideal results, but P&amp;D in line with the concept of micro-invasive neurosurgery was better than CD in terms of postoperative GCS score within 24 hours, duration of operative, intraoperative blood loss, and postoperative hospital duration.

Post-Market Surveillance Study of a Skull Flap Fixation Device: Cranfixer

Background and AimCranfixer was approved in 2017 by the Food and Drug Administration of Iran as a skull flap fixation and also a burr hole cover. The effectiveness and safety of this commercial medical device were investigated in detail by the regulatory auditors.Methods and Materials/PatientsCranfixer was used for ninety-five patients. Sixty patients were selected from a list if they had at least two follow-ups after surgery. The following variables were investigated: age, gender, number of Cranfixers, device loosening, infection, and prominence. Inaddition, a retrospective review was performed about the reason of surgery.ResultsFlap loosening and infection were the major variables surveyed. On average, two Cranfixers were used for each patient. Patients’ median age was 44 years. There was no sex preference (50% male). The craniotomy occurred in the frontal (50%), occipital (3%), parietal (20%), and temporal (27%)lobes. Based on examination and CT imaging, no cases of loosening were observed. Just in one patient, one of two Cranfixers was infected (P<0.001).ConclusionThe reliability and functionality of Cranfixer were proved in pre-market test and the results of this study confirm them. Cranfixer provides safe, reliable and long-term functionality.

Multi-level customized 3D printing for autogenous implants in skull tissue engineering

Three-dimensional (3D) printing of decellularized extracellular matrix (ECM) has been achieved to ensure real physiological environments for tissue engineering. However, the limited source, biocompatibility, and biosafety of decellularized ECM are deficiencies in its large clinical use. Autogenous ECM is biocompatible, bioactive, and biosafe, making it an optimal choice for future clinical applications of 3D printing. Here, we developed a multi-level customized 3D printing (MLC-3DP) strategy applying autogenous bone matrix (Auto-BM). This MLC-3DP includes shape specificity (shape), material specificity (Auto-BM), and cell specificity (autogenous cells) for true patient-specific repairs. Auto-BM (skull flaps) is readily accessible for specific patients after craniectomy, providing sufficient autogenous materials for MLC-3DP. Under mild conditions of this strategy, human-scale 3D printed samples can be fabricated using bioactive micron-sized Auto-BM particles. Multi-level customized autogenous bones (MLC-Auto-Bones) are finally obtained by combining autogenous bone marrow-derived mesenchymal stem cells (Auto-BMSCs). With autogenous materials and cells, MLC-Auto-Bones are inherently biocompatible and biosafe, providing good bioactivity for osteogenesis. In this implant, Auto-BMSCs can spontaneously differentiate into osteoblasts in vitro without additional osteogenic factors. In critical-sized skull defect models in vivo (3 months), implants integrate tightly to the defects’ margin, facilitate mineralization, and generate vascularized mature bone. This work provides not only feasibility for patient-specific implants for skull defects, but also potential patient-specific solutions for other similar clinical requirements.

Cranial Bone Flap Fixation: Comparison of Titanium-Based Device (Skull Fix) and PEEK-Based Device (Cranial Loop): Technical Report

AbstractBackground: Reconstruction of the cranial bone flap after craniocerebral surgery is crucial for preservation of skull symmetry, maintenance of aesthetics, brain protection, as well avoiding complications like floating or sunken skull flaps. A host of techniques and materials for fixation of the cranial flaps have emerged over the past several decades.Aim of Study: The aim of this study was to compare the clinical outcomes of bone flap fixation using peek-based (cranial loop) versus titanium-based (skull fix) fixation systems.Patients and Methods: Between July 2013 and December 2016 a series of 54 patients undergoing either an emergency or an elective craniotomy for different intracranial lesions in which the original bone flaps were refixed using cranial loop in 27 patients and skull fix in 27 patients. Clinical and radio-logical outcomes and complication rates were compared between these 2 groups.Results: Satisfactory results were achieved in both fixation systems. Epidural collection occurred in 4 patients 3 in skull fix and one in cranial loop, subdural collection in 4 patients 2 in cranial loop and one in skull fix treated conservatively. One case with cranial loop experienced a bone flap dislocation which was revised and refixed. Subcutaneous effusion occurred in two patients one in skull fix and one in cranial loop. One patient in skull fix developed a mild postoperative wound infection. Post-operative imaging showed satisfactory ana-tomical and morphological position of the flap in all patients.Conclusion: Skull fix and cranial loop are reasonable alternatives to present craniotomy fixation methods. They are easy to use, fast, safe, reliable with very acceptable cosmetic results. The main advantage of the cranial loop might ultimately lie in the absence of artifacts on post-operative CT or MR imaging.

Cranioplasty Using Autoclaved Autologous Skull Bone Flaps Preserved at Ambient Temperature.

Context:Decompressive craniectomy followed by cranioplasty (CP) uses autologous craniectomy flaps or synthetic materials like titanium. Sterilization and preservation methods for the autologous bone flaps continue to be the surgeon's choice.Aim:This study aimed to assess the short-term as well as long-term clinical outcomes of CP using autoclaved autologous bone grafts.Settings and Design:This retrospective observational study was performed on patients admitted in a tertiary care teaching neurosurgery department.Patients and Methods:Seventy-two patients who underwent CP with autoclaved autologous skull flaps preserved under ambient conditions with strict aseptic precautions were included in the study.Statistical Analysis Used:Frequencies and percentages of the various characteristics before and after the surgery were tabulated. Continuous variables were summarized as means and standard deviations.Results:The primary CP had a satisfactory clinical outcome in 62 cases (86.11%). Osteomyelitis was observed in four patients (5.56%) nearly 2 months after the surgery. Radiologically significant bone resorption was noted in a single patient (1.39%) after 1 year. Five patients (6.94%) developed bone fragmentation or fracture, and the mean time taken for this was about 36 months. In all these ten cases, secondary CP was successfully done using a prefabricated, patient-specific titanium mesh.Conclusions:The efficacy and safety of the studied craniectomy flaps used for cranial reconstruction showed a good patient outcome. Further retrospective studies with larger cohorts and prospective case–control studies are essential so as to issue standard guidelines for sterilization and preservation of autologous bone flaps.

Clinical observation on the early replantation of autologous periosteum-preserved skull flap

Objective To investigate the feasibility of preservation of the skull flap covered with periosteum in vivo and early cranioplasty in patients with decompressive craniectomy. Methods Sixty-seven patients underwent autologous cranioplasty using periosteum-covered skull flap preserved subcutaneously after decompressive craniectomy from January 2012 to December 2015 at Neurosurgery Department of Rizhao People's Hospital. Their data were retrospectively reviewed. Cranioplasty was conducted within 4-8 weeks after decompression for all patients. Part of the skull flap tissue was obtained in cranioplasty for identification of the bone activity by pathological examination. At follow-up, all patients received CT scan and 34 patients underwent SPECT to assess the healing and survival of skull flap. Results The size of skull flap in the 67 patients with cranioplasty remained the same as that at the time of decompression. Bones were not destructed, focal dead bone was not observed by the pathological examination. The postoperative follow-up lasted 1-2 years and CT scans revealed that the healing rate was 0%, 62.7% (42/67), and (67/67), 100% (53/53) at 1, 6, 12, 24 months after cranioplasty. No skull resorption was reported. Bone survival and good blood supply of the skull flap were demonstrated by SPECT. During the follow-up period, 1 (1.5%) patient had small subcutaneous hematoma, 4 (6.0%) patients developed subcutaneous effusion, and no intracranial or subcutaneous infection was observed. Conclusion Biological activities of skull flap in patients with decompressive craniectomy could remain well through subcutaneous preservation with periosteum, which might be useful for facilitating the good outcome of cranioplasty. Key words: Decompressive craniectomy; Periosteum; Transplantation, autologous; Cranioplasty; Preservation in vivo

Osteoblast and Bacterial Culture from Cryopreserved Skull Flap after Craniectomy: Laboratory Study.

ObjectiveCranioplasty using a cryopreserved skull flap is a wide spread practice. The most well-known complications of cranioplasty are postoperative surgical infections and bone flap resorption. In order to find biological evidence of cryopreserved cranioplasty, we investigated microorganism contamination of cryopreserved skulls and cultured osteoblasts from cryopreserved skulls.MethodsCryopreserved skull flaps of expired patients stored in a bone bank were used. Cryopreserved skulls were packaged in a plastic bag and wrapped with cotton cloth twice. After being crushed by a hammer, cancellous bone between the inner and outer table was obtained. The cancellous bone chips were thawed in a water bath of 30°C rapidly. After this, osteoblast culture and general microorganism culture were executed. Osteoblast cultures were done for 3 weeks. Microorganism cultures were done for 72 hours.ResultsA total of 47 cryopreserved skull flaps obtained from craniectomy was enrolled. Of the sample, 11 people were women, and the average age of patients was 55.8 years. Twenty four people had traumatic brain injuries, and 23 people had vascular diseases. Among the patients with traumatic brain injuries, two had fracture compound comminuted depressed. The duration of cryopreservation was, on average, 83.2 months (9 to 161 months). No cultured osteoblast was observed. No microorganisms were cultured.ConclusionIn this study, neither microorganisms nor osteoblasts were cultured. The biological validity of cryopreserved skulls cranioplasty was considered low. However, the usage of cryopreserved skulls for cranioplasty is worthy of further investigation in the aspect of cost-effectiveness and risk-benefit of post-cranioplasty infection.

A 200-1380-kHz Quadrifrequency Focused Ultrasound Transducer for Neurostimulation in Rodents and Primates: Transcranial In Vitro Calibration and Numerical Study of the Influence of Skull Cavity.

Low intensity transcranial focused ultrasound has been demonstrated to produce neuromodulation in both animals and humans. Primarily for technical reasons, frequency is one of the most poorly investigated critical wave parameters. We propose the use of a quadri-band transducer capable of operating at 200, 320, 850, and 1380 kHz for further investigation of the frequency dependence of neuromodulation efficacy while keeping the position of the transducer fixed with respect to the subject's head. This paper presents the results of the transducer calibration in water, in vitro transmission measurements through a monkey skull flap, 3-D simulations based on both a μ -computed tomography ( μ CT)-scan of a rat and on CT-scans of two macaques. A maximum peak pressure greater than 0.52 MPa is expected at each frequency in rat and macaque heads. According to the literature, our transducer can achieve neuromodulation in rodents and primates at each four frequencies. The impact of standing waves is shown to be most prominent at the lowest frequencies.

Rapid full-wave phase aberration correction method for transcranial high-intensity focused ultrasound therapies.

BackgroundNon-invasive high-intensity focused ultrasound (HIFU) can be used to treat a variety of disorders, including those in the brain. However, the differences in acoustic properties between the skull and the surrounding soft tissue cause aberrations in the path of the ultrasonic beam, hindering or preventing treatment.MethodsWe present a method for correcting these aberrations that is fast, full-wave, and allows for corrections at multiple treatment locations. The method is simulation-based: an acoustic model is built based on high-resolution CT scans, and simulations are performed using the hybrid angular spectrum (HAS) method to determine the phases needed for correction.ResultsComputation of corrections for clinically applicable resolutions can be achieved in approximately 15 min. Experimental results with a plastic model designed to mimic the aberrations caused by the skull show that the method can recover 95 % of the peak pressure obtained using hydrophone-based time-reversal methods. Testing using an ex vivo human skull flap resulted in recovering up to 70 % of the peak pressure at the focus and 61 % when steering (representing, respectively, a 1.52- and 1.19-fold increase in the peak pressure over the uncorrected case). Additionally, combining the phase correction method with rapid HAS simulations allows evaluation of such treatment metrics as the effect of misregistration on resulting pressure levels.ConclusionsThe method presented here is able to rapidly compute phases required to improve ultrasound focusing through the skull at multiple treatment locations. Combining phase correction with rapid simulation techniques allows for evaluation of various treatment metrics such as the effect of steering on pressure levels. Since the method computes 3D pressure patterns, it may also be suitable for predicting off-focus hot spots during treatments—a primary concern for transcranial HIFU. Additionally, the plastic-skull method presented here may be a useful tool in evaluating the effectiveness of phase correction methods.

Decompressive craniectomy or not: intraoperative experience in 41 patients with severe traumatic brain injury

ObjectiveTo present our experience in using decompressive craniectomy (DC) among severe traumatic brain injury (TBI) patients during operation and to discuss its indication. MethodsFrom October 2008 to May 2009, 41 patients aged between 18 and 75 years with severe TBI were included in this study. They underwent DC or non-DC (NDC) according to their intraoperative findings. Postoperative intracranial pressure (ICP), complications, requiring second operation or not and outcomes were observed. ResultsFifteen patients underwent DC and 26 patients did not. The average postoperative ICP of each patient was lower than 20mm Hg. For patients received DC, 2 had seizures after operation and 1 developed cerebrocele in the follow-up period; only 1 NDC patient had post-traumatic seizures, but none of them had delayed haematoma, cerebrospinal fluid fistula, cerebrocele or infections. At the end of follow-up, 10 patients died, 6 had the GOS of 2, 2 of 3, 9 of 4 and 14 of 5. ConclusionsDC is necessary to manage fulminant intracranial hypertension or intraoperative brain swelling. If there was not brain swelling after removal of the haematoma and necrotized neural tissues, it is safe to replace skull flap. The intraoperative finding is an important factor to decide whether to perform DC or not.

Clinical and Radiologic Outcome of a Less Invasive, Low-Cost Surgical Technique of Osteoplastic Decompressive Craniectomy.

Decompressive craniectomy (DC) has many technical details with significant constraining logistic/economic considerations in low-resource practice areas. We present a less invasive, cost-saving, and evidence-based technique of DC evolving in our practice. Earlier, we reported a technique of hinge decompressive craniectomy (hDC), in which the frontotemporoparietal skull flap is hinged on the temporal muscle. In this article we describe further refinements of this temporal muscle hDC : The scalp flap is raised in a galeal-skeletonizing plane preserving the subgaleal fascia on the pericranium, ready for use for duraplasty after durotomy. We performed a descriptive analysis of the clinical outcome of this surgical technique in a prospective consecutive cohort of patients with traumatic brain injury (TBI). The primary and secondary clinical outcome measures were in-hospital mortality and survival, respectively, and the immediate as well as long-term surgical wound issues. There were 40 cases, 38 men (95%) and 2 women over a 40-month period with a mild (n = 8), moderate (n = 17), or severe TBI (n = 15). As assessed by the computed tomography Rotterdam score, life-threatening significant brain injury was present in 90%. Poor clinical outcome occurred in about a third of cases (32.5%) mainly in the severe TBI group (77% of poor outcome) and not in the mild TBI group. Surgical site complications occurred in four patients (10%) The presented modified temporal muscle hDC technique offers significant economic advantages over the traditional surgical method of DC without added complications. Analysis of the clinical data in a consecutive prospective cohort of patients with potentially fatal TBI who underwent this surgical procedure showed a good outcome in at least two thirds.

Management of Dropped Skull Flaps.

Dropping a skull flap on the floor is an uncommon and avoidable mistake in the neurosurgical operating theater. This study retrospectively reviewed all incidents of dropped skull flaps in Ain-Shams University hospitals during a 10-year period to show how to manage this problem and its outcome. Thirty-one incidents of dropped skull flaps occurred from January 2004 to January 2014 out of more than 10,000 craniotomies. Follow-up period varied from 20 to 44 months. The bone flap was dropped while elevating the bone (n = 16), while drilling the bone on the operating table (n = 5), and during insertion of the bone flap (n = 10). Treatment included re-insertion of the skull flap after soaking it in povidone iodine and antibiotic solution (n = 17) or after autoclaving (n = 11), or discarding the skull flap and replacing it with a mesh cranioplasty in the same operation (n = 3). No bone or wound infection was noted during the follow-up period. Management of dropped skull flap is its prevention. Replacement of the skull flap, after decontamination, is an option that avoids the expense and time of cranioplasty.

Use of 3D reconstruction of emergency and postoperative craniocerebral CT images to explore craniocerebral trauma mechanism

We report a craniocerebral trauma case in which a man sustained severe skull fractures and cerebral contusions and it demanded elucidating the injury mechanism of being formed by strike or tumble. However, the initial features of skull fractures were mostly lost when the forensic pathologists involved in the case 5 months later because of injury healing and craniocerebral surgery. Therefore, we aimed to reconstruct the original skull fracture features by utilizing the digital reconstruction technologies in terms of CT (computed tomography) scanning, 3D (3-dimentional) reconstruction, and virtual surgical tools. The original fracture skull was assembled by using Mimics 13.0 based on the CT slices of postoperative head and the removed craniotomy skull flaps, which revealed fracture features of focal and overall skull deformation. Based on the assembly skull model and the contrecoup cerebral contusions, we conclude that the man suffered a tumble after being drunk and the serious craniocerebral trauma occurred. The case demonstrated that the digital reconstruction technologies can serve as effective approaches for forensic investigation in case of survived craniocerebral trauma patients without direct evidences interpreting the original trauma patterns, which could potentially be helpful in exploring the injury mechanisms.