Investigating the effects of PTEN mutations on cGAS-STING pathway in glioblastoma tumours.

BACKGROUND: PTEN is a tumour suppressor gene and well-known for being frequently mutated in several cancer types. Loss of immunogenicity can also be attributed to PTEN loss, because of its role in establishing the tumour microenvironment. Therefore, this study aimed to represent the link between PTEN and cGAS-STING activity, a key mediator of inflammation, in tumour samples of glioblastoma patients. METHODS: Tumour samples of 36 glioblastoma patients were collected. After DNA isolation, all coding regions of PTEN were sequenced and analysed. PTEN expression status was also evaluated by qRT-PCR, western blot, and immunohistochemical methods. Interferon-stimulated gene expressions, cGAMP activity, CD8 infiltration, and Granzyme B expression levels were determined especially for the evaluation of cGAS-STING activity and immunogenicity. RESULTS: Mutant PTEN patients had significantly lower PTEN expression, both at mRNA and protein levels. Decreased STING, IRF3, NF-KB1, and RELA mRNA expressions were also found in patients with mutant PTEN. Immunohistochemistry staining of PTEN displayed expressional loss in 38.1% of the patients. Besides, patients with PTEN loss had considerably lower amounts of IFNB and IFIT2 mRNA expressions. Furthermore, CD8 infiltration, cGAMP, and Granzyme B levels were reduced in the PTEN loss group. CONCLUSION: This study reveals the immunosuppressive effects of PTEN loss in glioblastoma tumours via the cGAS-STING pathway. Therefore, determining the PTEN status in tumours is of great importance, like in situations when considering the treatment of glioblastoma patients with immunotherapeutic agents.

Variations in Toll-like receptor and nuclear factor-kappa B genes and the risk of glioma.

PURPOSE: Glioblastoma (GBM) is the most aggressive primary brain tumour in the adult nervous system and is associated with a poor prognosis. NF-KB activation is an important driver of the malignant phenotype that confers a negative prognosis in patients with GBM. NF-KB plays a role in Toll-like Receptors (TLR)-induced tumourigenesis. The aim of the present study was to investigate the association of a promoter region polymorphism of NFKB1 gene encoding the p50 subunit of NF-KB, namely -94ins/del ATTG, the most widely discussed the TLR2 Arg753Gln, TLR4Asp299Gly and TLR4Thr399Ile polymorphisms, their combined effects, and the glioma risk. METHODS: A group of 120 Glioma patients and 225 control subjects were screened for these four polymorphisms using the PCR-RFLP method. RESULTS: Statistical analysis indicates that the ins/ins genotype of NFKB -94ins/delATTG (p=0.003), and the AA genotype of TLR4Asp299Gly (p < 0.001) are risk factors for glioma and people carrying the ins allele have an approximately 1.47 times susceptibility risk of glioma whereas GG genotype of TLR2Arg753Gln seems to be protective against glioma (p = 0.002). Combined genotype analysis showed that del/ins-GG genotype of TLR2Arg753Gln-NFKB1, del/ins + GG genotype of TLR4Asp299Gly-NFKB1, del/ins-CC genotype of TLR4Thr399Ile-NFKB1 were risk factors for glioma development. CONCLUSION: NFKB1 -94ins/delATTG and TLR4Asp299Gly polymorphisms are associated with increased glioma cancer risk in a Turkish population.

Cavernous Sinus and Parasellar Region: An Endoscopic Endonasal Anatomic Cadaver Dissection.

The aim of this study was to investigate the neurovascular structures of the cavernous sinus with the endonasal endoscopic transpterygoid approach on fresh human cadavers. Additionally, the course of internal carotid artery (ICA) and relevant anatomy was thoroughly investigated to refine the anatomical landmarks, exposure difficulties, potential complications, and limitations using the endonasal endoscopic technique. This study was carried out at an otolaryngology department of a tertiary medical center between June 2014 and June 2015. The surgical dissection was performed on 10 fresh human cadaver specimens using paranasal sinus and skull base endoscopic instruments. Cavernous sinuses and parasellar area were explored via an endoscopic endonasal transpterygoid approach. Dehiscence was present in 5 (25%) cavernous ICAs. Projection of the cavernous ICA on the whole lateral sphenoid wall was prominent in 6 (%30) sphenoid sinuses. Anterior curve was prominent in 12 (60%) cavernous ICAs, whereas posterior was prominent in 7 (35%). Mean distance between the lateral wall of eustachian tube orifice and petrous ICA was 19.50 ± 1.05 mm (range 18-22 mm). Cranial nerves of the cavernous sinus showed no variation. Control of the ICA is critical during the endonasal endoscopic approach to the cavernous sinus and skull base. The vidian nerve is a reliable and important landmark to the petrous ICA in the transpterygoid approach. Dissection of the eustachian tube and its relation to the ICA has to be kept in mind during nasopharyngeal surgery.

Double nasoseptal flap technique for endonasal pituitary surgery.

Endoscopic endonasal approach has been successfully used for the management of pituitary tumors; however, the loss of septal mucosa especially around sphenoethmoidal recess and posterior nasal septum might be a disadvantage of this technique. The aim of this study is to describe a variation of the endonasal approach, "double nasoseptal flap" technique in endoscopic transsphenoidal pituitary surgery, and to evaluate its outcomes. The technique depends on fully harvested bigger nasoseptal flap on one side and smaller on the other. Thirty patients were included. Functional results were assessed by preoperative and postoperative first month visual analogue scale (VAS), and morphology was evaluated by achieving intact septum from the sphenoid ostium to the columella. Sphenoid sinusitis, the presence of synechia and crusting in the sphenoethmoidal recess was also assessed. Mean VAS was 71 and 67 mm preoperatively and postoperatively, respectively (p > 0.01). There were no septal perforations, synechia, and sphenoid sinusitis postoperatively. Three patients had (10 %) crusts on sphenoethmoidal recess on first month postoperatively. Double nasoseptal flap technique has advantages, such as wider exposure during surgery; prepared flaps could be used if needed, better morphological and functional outcomes postoperatively. The technique is safe without any perforations and minimal crusting.

Osteointegration of a bisphenol-a-glycidyl-dimethacrylate composite and its use in anterior skull base defects: an experimental study in an experimental design model of cerebrospinal fluid leak.

OBJECT: Promising clinical results were reported in watertight closure of anterior skull base defects (ASBDs) with bisphenol-a-glycidyl-dimethacrylate (bis-GMA)-based materials to prevent the cerebrospinal fluid leaks. However, interrelation of these materials with surrounding bones in histologic level, referred to as the osteointegration, has not been reported in the anterior skull base. In addition, an illustrative case with an ASBD that was repaired using a bis-GMA composite has been presented. METHODS: Twenty New Zealand rabbits were divided into 4 groups: control and sham groups consisted of 2 and 6 rabbits, respectively. The "skull base defect" group (n = 6) underwent a unifrontal craniectomy and an iatrogenic ASBD followed by creating a dural defect to obtain a cerebrospinal fluid leak. Similar bony and dural defects were acquired in the "repair with bis-GMA based allograft" group (n = 6), but the bony defect was closed with bis-GMA-based allograft. RESULTS: All animals in the "skull base defect" group died in 3 weeks after surgery. There were no animal losses in the "repair with bis-GMA based allograft" group at the sixth month. Histologic evaluation revealed complete osteointegration of bis-GMA composite with surrounding bones. CONCLUSIONS: bis-GMA based allograft achieved a watertight repair of the ASBD. Histologic findings of this study showed that bis-GMA composite is a reliable material to be used in the closure of anterior skull base bony defects.

Pain intensity, spine structure, and body composition in patients with acute discogenic lumbar radiculopathy.

OBJECTIVE: This study aimed to compare the pain intensity, spine structure, and body composition according to functional disability levels in patients with acute discogenic lumbar radiculopathy (DLR). METHODS: A total of 118 women (n = 83) and men (n = 35) patients with acute DLR (mean age: 51.87 ± 13.38 years) were included in the study. The function ability was measured with the Oswestry Disability Index, pain intensity was measured with the Visual Analogue Scale, spine structure was measured with the Spinal Mouse® device, and body composition was measured with the Bioelectrical Impedance Analysis System. RESULTS: Patients with mild functional disability levels had significantly lower activity (p˂.001) and night pain intensity (p = 0.001) than patients with moderate, severe, and completely functional disability levels, and patients with completely functional disability levels had significantly higher rest pain intensity (p = 0.005) than patients with mild, moderate, and severe functional disability levels. Patients with mild functional disability levels had significantly better spine check scores (p = 0.001), posture (p = 0.005), and mobility (p = 0.003) than patients with moderate, severe, and completely functional disability levels. Patients with mild functional disability levels had significantly lower fat percentage (p = 0.032), and higher basal metabolic rate (p = 0.024) than patients with moderate, severe, and completely functional disability levels. CONCLUSION: Pain intensity, spinal structure, and body composition of acute DLR patients differ greatly according to their functional disability levels. Although it is known that the level of functional disability of patients is a result of the severity or prognosis of the disease, performing different treatment methods aimed at decreasing the functional disability level of patients by health professionals may be important in terms of coping with the disease.

The Effect of Preoperative Three Dimensional Modeling and Simulation on Outcome of Intracranial Aneursym Surgery.

OBJECTIVE: Three-dimensional (3D) printing in vascular surgery is trending and is useful for the visualisation of intracranial aneurysms for both surgeons and trainees. The 3D models give the surgeon time to practice before hand and plan the surgery accordingly. The aim of this study was to examine the effect of preoperative planning with 3D printing models of aneurysms in terms of surgical time and patient outcomes. METHODS: Forty patients were prospectively enrolled in this study and divided into two groups : groups I and II. In group I, only the angiograms were studied before surgery. Solid 3D modelling was performed only for group II before the operation and was studied accordingly. All surgeries were performed by the same senior vascular neurosurgeon. Demographic data, surgical data, both preoperative and postoperative modified Rankin scale (mRS) scores, and Glasgow outcome scores (GOS) were evaluated. RESULTS: The average time of surgery was shorter in group II, and the difference was statistically significant between the two groups (p<0.001). However, no major differences were found for the GOS, hospitalisation time, or mRS. CONCLUSION: This study is the first prospective study of the utility of 3D aneurysm models. We show that 3D models are useful in surgery preparation. In the near future, these models will be used widely to educate trainees and pre-plan surgical options for senior surgeons.

Molecular dynamic simulation and functional analysis of pathogenic PTEN mutations in glioblastoma.

PTEN, a dual-phosphatase and scaffold protein, is one of the most commonly mutated tumour suppressor gene across various cancer types in human. The aim of this study therefore was to investigate the stability, structural and functional effects, and pathogenicity of 12 missense PTEN mutations (R15S, E18G, G36R, N49I, Y68H, I101T, C105F, D109N, V133I, C136Y, R173C and N276S) found by next generation sequencing of the PTEN gene in tissue samples obtained from glioblastoma patients. Computational tools and molecular dynamic simulation programs were used to identify the deleterious effects of these mutations. Furthermore, PTEN mRNA and protein expression levels were evaluated by qRT-PCR, Western Blot, and immunohistochemistry staining methods. Various computational tools predicted strong deleterious effects for the G36R, C105F, C136Y and N276S mutations. Molecular dynamic simulation revealed a significant decrease in protein stability for the Y68H and N276S mutations when compared with the wild type protein; whereas, C105F, D109N, V133I and R173C showed partial stability reduction. Significant residual fluctuations were observed in the R15S, N49I and C136Y mutations and radius of gyration graphs revealed the most compact structure for D109N and least for C136Y. In summary, our study is the first one to show the presence of PTEN E18G, N49I, D109N and N276S mutations in glioblastoma patients; where, D109N is neutral and N276S is a damaging and disease-associated mutation.Communicated by Ramaswamy H. Sarma.

Pneumatization degree of the anterior clinoid process: a new classification.

The objective of this study is to determine the incidence and degree of anterior clinoid process pneumatization, in addition highlighting to their clinical significance. Multidetector-row CT scans of the skull base were reviewed in 648 subjects between 2007 and 2008. The presence of pneumatized anterior clinoid process and its degree were studied and documented. These data were statistically analyzed. Pneumatization of the ACP was found in 62 of 648 patients (9.6%) including 32 (51.6%) men and 30 (48.4%) women. The age of these patients ranged from 21 to 82 years (mean, 41 +/- 15.7 years). Pneumatization of the ACP occurred only on the left side in 14 cases (22.6%), only on the right side in 11 cases (17.7%), and bilaterally in 37 patients (59.7%). ACP pneumatization Type I, in which less than 50% of the ACP is pneumatized, was found in 47 of 124 sides (38%), Type II, in which more than 50% but not totally pneumatized ACP, was found in 28 of 124 sides (22.6%), and Type III, in which the ACP is totally pneumatized, was found in 22 of 124 sides (17.7%). The incidence of Type I in the general population was 6.6%, Type II was 3.5%, and Type III was 2.5%. Radiologically recognizing the degree of ACP pneumatization is important in decreasing the incidence of surgical complications during anterior clinoidectomy. Proper intraoperative management can be undertaken with special attention to the new classification.

The expression of astroglial glutamate transporters in patients with focal cortical dysplasia: an immunohistochemical study.

PURPOSE: An abnormal increase in the extracellular glutamate is thought to play a crucial role in the initiation, spread, and maintenance of seizure activity.In normal conditions, the majority of this excess glutamate is cleared via glial glutamate transporters (EAAT-1 and EAAT-2). We aimed to examine the immunohistochemical expression of these transporters in the dysplastic tissues of patients with focal cortical dysplasia (FCD). METHODS: The parafin-embedded dysplastic tissues of 33 patients who were operated on due to medically intractable epilepsy and histopathologically diagnosed with FCD between 2001 and 2006 were stained immunohistochemically with appropriate antibodies, and the distribution and intensity of immunoreactivity (IR) of EAAT-1 and EAAT-2 were examined.The findings were compared with the histologically normal tissues of five patients who underwent temporal lobectomy for epilepsy surgery and 10 fresh postmortem cases. RESULTS: In the majority of the patients, the EAAT-1 and EAAT-2 IR were decreased, their astrocytic expression were lower, and the pattern of distribution were more diffused when compared to the control groups.Analyzing these findings according to the types of FCD revealed that as the severity of the dysplasia increased, the IR and astrocytic expression of both transporters are decreased and their distribution tend to be more "diffused." CONCLUSION: The results of this study suggest a relationship between the decreased glutamate transporter expressions in dysplastic tissues which,in turn, may cause increased extracellular concentrations of glutamate and FCD pathophysiology.Further studies with larger patient populations,investigating the expression of glutamate transporters at mRNA and protein levels, are required to clarify their roles in the pathophysiology of FCD.

Intraosseous meningioma: a rare tumor reconstructed with porous polyethylene.

A 45-year-old woman described the pain and the swelling at the left frontoparietal region. No significant findings were noted on physical examination, except a heterogeneous palpable lesion at the described region. Computed tomographic scan revealed an expansive bone lesion with homogeneous density, whereas magnetic resonance imaging revealed similar findings with no contrast enhancement. The lesion was totally resected, and cranioplasty with a porous polyethylene sheet (Medpor Biomaterial; Porex Surgical, Newnan, GA) was achieved. Histopathologic examination revealed an intraosseous meningioma. As far as we know, this case is the first case, in which total excision of the interosseous meningioma is followed by reconstruction with Medpor.

Endoscopic endonasal anatomy and approaches to the anterior skull base: a neurosurgeon's viewpoint.

OBJECTIVES: The objective of this study was to review the endoscopic anatomy of the anterior skull base, defining the pitfalls of endoscopic endonasal approaches to this region. Recently, these approaches are gaining popularity among neurosurgeons, and the details of the endoscopic anatomy and approaches are highlighted from the neurosurgeons' point of view, correlated with demonstrative cases. MATERIALS AND METHODS: Twelve fresh adult cadavers were studied (n = 12). We used Karl Storz 0 and 30 degrees, 4 mm, 18- and 30-cm rod lens rigid endoscope in our dissections. After preparation of the cadaveric specimens, we approached the anterior skull base by the extended endoscopic endonasal approach. RESULTS: After resection of the superior portion of the nasal septum, bilateral middle and superior turbinates, and bilateral anterior and posterior ethmoidal cells, we could obtain full exposure of the anterior skull base. The distance between optic canal and the posterior ethmoidal artery ranged from 8 to 16 mm (mean, 11.08 mm), and the distance between posterior ethmoidal artery and the anterior ethmoidal artery ranged from 10 to 17 mm (mean, 13 mm). After resecting the anterior skull base bony structure and the dura between the 2 medial orbital walls, we could visualize the olfactory nerves, interhemispheric sulcus, and gyri recti. With dissecting the interhemispheric sulcus, we could expose the first (A1) and second (A2) segments of the anterior cerebral artery, anterior communicating artery, and Heubner arteries. CONCLUSIONS: This study showed that extended endoscopic endonasal approaches are sufficient in providing wide exposure of the bony structures, and the extradural and intradural components of the anterior skull base and the neighboring structures providing more controlled manipulation of pathologic lesions. These approaches need specific skill and learning curve to achieve more minimally invasive interventions and less postoperative complications.

Endoscopic management of posterior fossa arachnoid cyst in an adult: case report and technical note.

The authors report a case of large arachnoid cysts of the posterior fossa treated by endoscopic surgery. A 40-year-old man was admitted with a 3-month history of headache and progressive gait imbalance, with no significant medical history. At the time of admission, neurological examination revealed no abnormalities except for tandem imbalance. Brain computerized tomography (CT) scan and magnetic resonance imaging (MRI) revealed a posterior fossa arachnoid cyst (PFAC) causing brain stem compression accompanied by hydrocephalus. The patient was treated by endoscopic fenestration of the cyst with a paramedian suboccipital transcortical approach. Postoperatively the patient's complaints showed improvement and he was discharged with no complications. Follow up MRI showed a decrease in the cyst's size and the hydrocephalus with decompression of the brain stem.

Computed tomography vs. magnetic resonance imaging in unstable cervical spine injuries.

BACKGROUND: This study aimed to investigate the role of computed tomography (CT) in identifying missed unstable blunt cervical injuries. METHODS: Patients admitted to the emergency department between June 2014 and June 2018 with a diagnosis of blunt cervical trauma were included in this study. All participants underwent cervical magnetic resonance imaging (MRI) after an initial cervical CT investigation. All imaging results were reviewed, and decisions were taken by the consensus of a team consisting of an emergency medicine specialist, a neuroradiologist, and a neurosurgeon. Other variables included age, sex, the Glasgow Coma Scale, medical comorbidities, multi-trauma, neurological deficits, accompanying intracranial hemorrhage, extremity fractures, and the mechanism of the injury. RESULTS: Data for 195 patients were analyzed. The mean (±standard deviation) age of the participants was 47.34±21.90 years, and 140 (71.8%) were males. Eighteen patients (9.2%) were below age <18. The most frequent mechanism of injury was fall from height (n=100; 51.3%). Using MRI as the gold standard, the sensitivity of CT in diagnosing unstable cervical injury was 77.7% (95% CI [67.1-86.1]), while its specificity was 100.0% (95% CI [59.0-100.0]). CONCLUSION: Although computed tomography is relatively good in diagnosing unstable cervical injuries, its sensitivity in detecting positive cases is not as successful. Thus, the use of MRI in patients with an unstable injury seems to be warranted.

Supratentorial high grade astroblastoma: report of two cases and review of the literature.

Astroblastoma is a rare glial tumor with uncertain histopathological origin and unpredictable clinical behavior. In this report, the authors present two cases of high grade intracerebral astroblastomas. Both tumors occurred in children as supratentorial, well-circumscribed, peripheral masses. The lesions differed radigraphically; one contained a huge cystic component and heterogeneously enhancing mural nodule while the other appeared as a prominently contrastenhancing solid mass lesion. Both patients were treated with surgery and postoperative radiotherapy. They were followed-up long-term and no recurrence of the tumor was detected in either case. We also discussed the radiological and histological characteristics with prognostic features.

Neuroanatomical Aspects of the Temporo-Parieto-Occipital Junction and New Surgical Strategy to Preserve the Associated Tracts in Junctional Lesion Surgery: Fiber Separation Technique.

AIM: To describe the location of each white matter pathways around the temporo-parieto-occipital junction (TPOJ) and the dissections performed using focal fiber dissection and fiber separation techniques (FST). These areas play an important role in human language processing and high-level brain functions. Thus, it is important to identify the association of the fascicles as well as their courses to plan safe and effective surgical target vectors. MATERIAL AND METHODS: Thirty formalin-fixed human hemispheres and two formalin-fixed human heads were dissected with focal fiber dissection and FST under 6-40x magnification using a surgical microscope and real-time magnetic resonance imaging navigation system. Two- and three-dimensional anatomical and surgical pictures were obtained and processed using high dynamic range photography (Photomatix) and were correlated to radiological images of the case with glioblastoma of the TPOJ. RESULTS: The trajectory and connectivity of these fibers as well as their surgical importance in performing FST in cadaver dissections were demonstrated with correlation of the surgical, radiological, and anatomical images. CONCLUSION: The microanatomy of the TPOJ and related structures, emphasizing the position of each white matter pathway, has been described. Understanding the composition of each region is critical in preventing intraoperative brain injury that could lead to functional deficits.

Comparison between Rescue Flap and Double Flap Technique.

Objectives Endoscopic techniques in pituitary surgery lead to inevitable mucosal loss of the sphenoethmoidal recess and posterior nasal septum in the nasal cavity. There is no other comparative study between primary reconstruction of septal perforation and secondary healing in the literature. The aim of this study is to evaluate postoperative patient morbidity with or without posterior septal perforation in endonasal pituitary surgery by comparing two commonly used techniques: rescue and double nasoseptal flaps. Design Prospectively randomized study. Setting Tertiary academic center. Participants Sixty patients underwent endoscopic endonasal pituitary surgery. Main Outcomes and Measures Functional results (breathing) using visual analog scale (VAS), sphenoid sinusitis, presence of synechia, perforation in the posterior septum, and crusting in the sphenoethmoidal recess were assessed. Results Pre- and postoperative mean VAS scores were 71.67 ± 11.47 and 67.67 ± 9.71 mm in the intact septum group and 77.67 ± 14.06 and 62.67 ± 10.48 mm in the posterior septal perforation group. There was a significant difference between pre- and postoperative VAS values in all groups. There was significant worsening in both groups; worsening in VAS values was much higher in the posterior septal perforation group. In the posterior septal perforation group, much more crusting was seen. Conclusions This is the first study to compare the postoperative patient morbidity in endoscopic endonasal pituitary surgery with and without a posterior septal perforation. Reconstruction of the posterior septum along with less mucosal loss yields better postoperative nasal symptom score.

The Effect of Endoscopic Endonasal Transsphenoidal Skull Base Surgery on Cochlear Function.

Endoscopic transsphenoidal skull base surgery (ETSS) has become a standard approach in the treatment of sellar and clival lesions, such as pituitary adenoma and chordoma. Due to the close proximity of the clivus and the sella turcica to the inner ear, it is thought that bone drilling in the surgery may have effects on hearing. The aim of this study was to assess the effect of bone drilling in ETSS procedure on cochlear function. This study was performed on 18 patients who underwent ETSS procedure between December 2016 and May 2017. The study was designed as a prospective study. All of the data were prospectively collected. These included demographic data, date of surgery, type of surgery, preoperative pure-tone audiometry, and preoperative and postoperative distortion product otoacoustic emission (DPOAE) measurements. Of the DPOAE measurements of the patients who were operated for pituitary adenoma, there was a statistically significant difference between the signal-to-noise ratio (SNR) measurements at 0.5, 1, 2 and 4 kHz ( p < 0.05). Additionally, there were no significant differences in preoperative and postoperative SNR measurements of six patients who were selected for clivus chordoma. When the preoperative and postoperative tonal audiometric tests of the patients were compared, no statistically significant difference was found ( p > 0.05). In conclusion, it is found that bone drilling in ETSS procedure has a negative effect on cochlear function in the early period. This is the first study to evaluate the degree of noise-induced cochlear damage in patients who were gone under ETSS procedure.

A case report: a noninfantile desmoplastic astrocytoma.

UNLABELLED: INTRODUCTION AND CASE DESCRIPTION: Desmoplastic infantile astrocytomas (DIA) are rare intracranial tumors of infancy with distinctive clinical and radiological features. Despite their radiologically aggressive appearance they tend to follow a benign course with favorable prognosis even after subtotal resections. Non-infantile cases are rarely encountered with only four cases reported before. The authors present a non-infantile DIA in a 4 years old female patient and discuss the clinical features, diagnosis, treatment of this rare entity. CONCLUSION: Although accepted as a tumor of infancy, DIA can also be encountered in older patients. Careful diagnosis and differentiation of DIA cases with other tumors, particularly malignant astrocytomas is important since the therapeutic strategies may differ.

Creation of 3-Dimensional Life Size: Patient-Specific C1 Fracture Models for Screw Fixation.

BACKGROUND: Transarticular screw fixation has fatal complications such as vertebral artery (VA), carotid artery, and spinal cord injuries. The landmarks for deciding the entry point for C1 lateral mass screws were clarified by using life-size 3-dimensional (3D) patient-specific spine models. METHODS: This study included a total of 10 patients with C1 fractures. Dual-energy computed tomography (CT) scan data from C1 pre- and postscrewing were modified into 3D patient-specific life-size cervical spine models. The detailed information, such as bony and vascular elements, of 13 separate parameters of C1 was used as an intraoperative reference. RESULTS: 3D patient-specific models were created preoperatively with the fracture and postoperatively with the screwed vertebrae. After CT scans of the models were measured, the life-size patient-specific models were proven to be individualized. 3D models assisted in determining the fracture locations, pedicle sizes, and positions of the VA. The range of the measurements for ideal point of entry reveals the need for patient-specific intervention was required. CONCLUSIONS: 3D models were used in surgical planning maximizing the possibility of ideal screw position and providing individualized information concerning cervical spinal anatomy. The individualized 3D printing screw insertion template was user-friendly, of moderate cost, and it enabled a radiation-free cervical screw insertion.