RNA sequencing for research and diagnostics in clinical oncology.

Molecular diagnostics is becoming one of the major drivers of personalized oncology. With hundreds of different approved anticancer drugs and regimens of their administration, selecting the proper treatment for a patient is at least nontrivial task. This is especially sound for the cases of recurrent and metastatic cancers where the standard lines of therapy failed. Recent trials demonstrated that mutation assays have a strong limitation in personalized selection of therapeutics, consequently, most of the drugs cannot be ranked and only a small percentage of patients can benefit from the screening. Other approaches are, therefore, needed to address a problem of finding proper targeted therapies. The analysis of RNA expression (transcriptomic) profiles presents a reasonable solution because transcriptomics stands a few steps closer to tumor phenotype than the genome analysis. Several recent studies pioneered using transcriptomics for practical oncology and showed truly encouraging clinical results. The possibility of directly measuring of expression levels of molecular drugs' targets and profiling activation of the relevant molecular pathways enables personalized prioritizing for all types of molecular-targeted therapies. RNA sequencing is the most robust tool for the high throughput quantitative transcriptomics. Its use, potentials, and limitations for the clinical oncology will be reviewed here along with the technical aspects such as optimal types of biosamples, RNA sequencing profile normalization, quality controls and several levels of data analysis.

Disparity between Inter-Patient Molecular Heterogeneity and Repertoires of Target Drugs Used for Different Types of Cancer in Clinical Oncology.

Inter-patient molecular heterogeneity is the major declared driver of an expanding variety of anticancer drugs and personalizing their prescriptions. Here, we compared interpatient molecular heterogeneities of tumors and repertoires of drugs or their molecular targets currently in use in clinical oncology. We estimated molecular heterogeneity using genomic (whole exome sequencing) and transcriptomic (RNA sequencing) data for 4890 tumors taken from The Cancer Genome Atlas database. For thirteen major cancer types, we compared heterogeneities at the levels of mutations and gene expression with the repertoires of targeted therapeutics and their molecular targets accepted by the current guidelines in oncology. Totally, 85 drugs were investigated, collectively covering 82 individual molecular targets. For the first time, we showed that the repertoires of molecular targets of accepted drugs did not correlate with molecular heterogeneities of different cancer types. On the other hand, we found that the clinical recommendations for the available cancer drugs were strongly congruent with the gene expression but not gene mutation patterns. We detected the best match among the drugs usage recommendations and molecular patterns for the kidney, stomach, bladder, ovarian and endometrial cancers. In contrast, brain tumors, prostate and colorectal cancers showed the lowest match. These findings provide a theoretical basis for reconsidering usage of targeted therapeutics and intensifying drug repurposing efforts.

Molecular pathway activation - New type of biomarkers for tumor morphology and personalized selection of target drugs.

Anticancer target drugs (ATDs) specifically bind and inhibit molecular targets that play important roles in cancer development and progression, being deeply implicated in intracellular signaling pathways. To date, hundreds of different ATDs were approved for clinical use in the different countries. Compared to previous chemotherapy treatments, ATDs often demonstrate reduced side effects and increased efficiency, but also have higher costs. However, the efficiency of ATDs for the advanced stage tumors is still insufficient. Different ATDs have different mechanisms of action and are effective in different cohorts of patients. Personalized approaches are therefore needed to select the best ATD candidates for the individual patients. In this review, we focus on a new generation of biomarkers - molecular pathway activation - and on their applications for predicting individual tumor response to ATDs. The success in high throughput gene expression profiling and emergence of novel bioinformatic tools reinforced quick development of pathway related field of molecular biomedicine. The ability to quantitatively measure degree of a pathway activation using gene expression data has revolutionized this field and made the corresponding analysis quick, robust and inexpensive. This success was further enhanced by using machine learning algorithms for selection of the best biomarkers. We review here the current progress in translating these studies to clinical oncology and patient-oriented adjustment of cancer therapy.

Effect of irrigation on fibrinolytic rtPA therapy in a clot model of intracerebral haemorrhage: a systematic in vitro study.

OBJECTIVE: Although fibrinolytic therapy is an upcoming treatment for intracerebral haemorrhage (ICH), standard guidelines are lacking, and some clinical issues persist. Here, we used our recently devised clot model of ICH to systematically analyse effects of irrigation and cerebrospinal fluid (CSF) on fibrinolysis. METHODS: In vitro clots of human blood (25 ml) were generated and a catheter irrigation system was applied to deliver fluid/treatment. Clots were weighed before and after treatment and compared to rtPA treatment alone. First various drainage periods (15, 30 and 60 min; n = 3 each) and irrigation rates (0, 15, 90 and 180 ml/h; n = 3-5 each) were tested, followed by rtPA administration (1 mg, 15 min incubation) at each irrigation rate. Potential fibrinolytic effect of CSF was examined by incubation with 5 ml healthy vs. haemorrhagic CSF (n = 3 each). To assess a washout effect treatment with saline (0.9%), rtPA (1 mg) and high-rate irrigation (180 ml/h) were compared with measuring plasminogen level before and after. Furthermore clots were treated with a combination of plasminogen (150% serum concentration) and rtPA (1 mg). RESULTS: Relative clot end weights after 60 min irrigation system treatments were 66.3 ± 3.8% (0 ml/h), 46.3 ± 9.5% (15 ml/h), 46.5 ± 7.1% (90 ml/h) and 53.3 ± 4.1% (180 ml/h). At a lower irrigation rate (15 ml/h), relative end weights were lowest (49.5 ± 4.6%) after 60 min (15 min: 62 ± 4.3%, p = 0.016; 30 min: 62.90 ± 1.88%, p = 0.012). The combination of rtPA and irrigation produced following relative end weights: 0 ml/h, 35 ± 3.2%; 15 ml/h, 32.1 ± 5.7%; 90 ml/h, 36.7 ± 6.3% and 180 ml/h, 41.9 ± 7.5%. No irrigation (0 ml/h) versus rtPA alone showed a significant difference (p < 0.0001) in higher clot weight reduction by rtPA. Similar rtPA+15 ml/h irrigation achieved a significant higher weight reduction compared to 15 ml/h irrigation alone (p = 0.0124). No differences were evident at 90 and 180 ml/h irrigation rates with and without rtPA. Healthy (55.1 ± 5%) or haemorrhagic (65.2 ± 6.2%) CSF showed no fibrinolytic activity. Plasminogen levels in clots declined dramatically (> 80% initially to < 10%) after 1 mg single rtPA dosing and high-rate (180 ml/h) irrigation. The fibrinolytic benefit of adding plasminogen to rtPA was marginal. CONCLUSIONS: In our in vitro clot model, irrigation combined with rtPA (vs. rtPA alone) conferred no added lytic benefit. Likewise, exposure to haemorrhagic CSF did not increase clot lysis.

Evaluation of robot-guided minimally invasive implantation of 2067 pedicle screws.

Objective Recent studies have investigated the role of spinal image guidance for pedicle screw placement. Many authors have observed an elevated placement accuracy and overall improvement of outcome measures. This study assessed a bi-institutional experience following introduction of the Renaissance miniature robot for spinal image guidance in Europe. Methods The medical records and radiographs of all patients who underwent robot-guided implantation of spinal instrumentation using the novel system (between October 2011 and March 2015 in Mainz and February 2014 and February 2016 in Regensburg) were reviewed to determine the efficacy and safety of the newly introduced robotic system. Screw position accuracy, complications, exposure durations to intraoperative radiation, and reoperation rate were assessed. Results Of the 413 surgeries that used robotic guidance, 406 were via a minimally invasive approach. In 7 cases the surgeon switched to conventional screw placement, using a midline approach, due to referencing problems. A total of 2067 screws were implanted using robotic guidance, and 1857 screws were evaluated by postoperative CT. Of the 1857 screws, 1799 (96.9%) were classified as having an acceptable or good position, whereas 38 screws (2%) showed deviations of 3-6 mm and 20 screws (1.1%) had deviations > 6 mm. Nine misplaced screws, implanted in 7 patients, required revision surgery, yielding a screw revision rate of 0.48% of the screws and 7 of 406 (1.7%) of the patients. The mean ± SD per-patient intraoperative fluoroscopy exposure was 114.4 (± 72.5) seconds for 5.1 screws on average and any further procedure required. Perioperative and direct postoperative complications included hemorrhage (2 patients, 0.49%) and wound infections necessitating surgical revision (20 patients, 4.9%). Conclusions The hexapod miniature robotic device proved to be a safe and robust instrument in all situations, including those in which patients were treated on an emergency basis. Placement accuracy was high; peri- and early postoperative complication rates were found to be lower than rates published in other series of percutaneous screw placement techniques. Intraoperative radiation exposure was found to be comparable to published values for other minimally invasive and conventional approaches.

In vivo multiphoton tomography and fluorescence lifetime imaging of human brain tumor tissue.

High resolution multiphoton tomography and fluorescence lifetime imaging differentiates glioma from adjacent brain in native tissue samples ex vivo. Presently, multiphoton tomography is applied in clinical dermatology and experimentally. We here present the first application of multiphoton and fluorescence lifetime imaging for in vivo imaging on humans during a neurosurgical procedure. We used a MPTflex™ Multiphoton Laser Tomograph (JenLab, Germany). We examined cultured glioma cells in an orthotopic mouse tumor model and native human tissue samples. Finally the multiphoton tomograph was applied to provide optical biopsies during resection of a clinical case of glioblastoma. All tissues imaged by multiphoton tomography were sampled and processed for conventional histopathology. The multiphoton tomograph allowed fluorescence intensity- and fluorescence lifetime imaging with submicron spatial resolution and 200 picosecond temporal resolution. Morphological fluorescence intensity imaging and fluorescence lifetime imaging of tumor-bearing mouse brains and native human tissue samples clearly differentiated tumor and adjacent brain tissue. Intraoperative imaging was found to be technically feasible. Intraoperative image quality was comparable to ex vivo examinations. To our knowledge we here present the first intraoperative application of high resolution multiphoton tomography and fluorescence lifetime imaging of human brain tumors in situ. It allowed in vivo identification and determination of cell density of tumor tissue on a cellular and subcellular level within seconds. The technology shows the potential of rapid intraoperative identification of native glioma tissue without need for tissue processing or staining.

Medication reconciliation for patients undergoing spinal surgery.

PURPOSE: In recent years, a marked increase of spinal operations prompted a debate on quality issues. Besides obvious factors, such as the surgical technique, medication safety has been identified as one of the major risk factors for patients undergoing anesthesia and surgery. While the issue has already been addressed by hospital pharmacist and anesthesiologists, the prescription of correct medication remains within the surgeons' responsibility. We, therefore, investigated medication-related errors in spinal instrumentation patients and applied current medication reconciliation strategies. METHODS: We performed a data survey on all patients undergoing spinal instrumentation in 2011. Risk factors for medication safety were identified and prioritized. Specific counter-measures were introduced in 2012 and evaluated in 2013. RESULTS: 147 patients were included in the 2011 and 162 in the 2013 survey. As top five risk factors we identified the preoperative stopping of medication, recording the medication history, prescription process of postoperative analgetics and anticoagulants and the medication list at discharge. Specific counter-measures included standardization of preparations, doses and the prescription process and improving access to this information (online and via a smartphone application). In elective patients, recording the medication histories was delegated to a hospital pharmacist and informative flyers and posters were used to integrate the patients themselves into the process. Counter-measures directed against the first four risk factors resulted in a significant reduction of medication errors. The last risk factor was targeted by instructing the responsible staff only, which proved to be a rather ineffective measure. CONCLUSIONS: Medication safety could be significantly improved by implementation of counter-measures specific to the identified risk factors.

Minimally invasive instrumentation of uncomplicated cervical fractures.

PURPOSE: Many authors favor conservative treatment options in oligo-symptomatic non-dislocated cervical fractures. This is mainly because of adverse events, anesthesia times and blood loss associated with surgical treatment of these injuries. We, therefore, sought to minimize the invasiveness of the surgical treatment of simple cervical fractures using image-guidance and a percutaneous approach. METHODS: Iso-C3D-based image guidance was used to place unilateral lag screws and conventional screws in pedicles, isthmi and lateral masses C1-C6. The navigation reference marker array was attached to the Mayfield clamp avoiding any additional skin incisions. Drilling of the screws trajectories was performed using a high speed drill with diamond tip, minimizing the risk of dislocations of cervical vertebrae and/or bone fragments relative to the iso-C3D scan to which the navigation system was registered. RESULTS: Image-guided percutaneous placement of cervical pedicle, isthmic and lateral mass screws resulted in correct screw placement in all six cases (three hangman fractures, three odontoid fracture Anderson 2 in elderly patients and one C6 posttraumatic pedicular pseudoarthrosis). Average blood loss was 194 ml, total average operating time 106 min and average X-ray time 3.8 min (395 cGy/cm(2)) including iso-C3D imaging. CONCLUSION: The technique presented here was found to be a feasible minimally invasive treatment option for uncomplicated cervical fractures. Besides to our best knowledge, we here present the first percutaneous implantation of lateral mass screws.

Interface transition checklists in spinal surgery.

ISSUE: Recently, quality tools have been promoted to improve patient safety and process efficiency in healthcare. While surgeons primarily focused on surgical issues, like infection rates or implant design, we introduced pre-admission and preoperative checklists in the early 2000s. INITIAL ASSESSMENT: To assess the efficiency of these tools in a neurosurgical department, we performed a survey of all spinal instrumentation patients operated in 2011 (n = 147). The results revealed several problems. CHOICE OF SOLUTION: We consequently redesigned the checklists accompanied by flanking measures, such as written  and online accessible standards. Furthermore, the staff was trained to use the updated quality tools. IMPLEMENTATION: The measures were implemented in 2012. EVALUATION: Results were re-evaluated in a second survey in 2013 (n = 162). We found that the use of pre-admission checklists significantly increased from 47 to 96%, while the use of preoperative checklists significantly decreased from 86 to 75%. Within the same period, the quality and completeness of the checklists did, however, increase, so that in 2013, 43% of the patients had a completely processed preoperative checklist, compared to 29% in 2011. LESSONS LEARNED: The introduction of checklists alone did not in itself guarantee an improved workflow. The introduction must be accompanied by other measures, like written standards and regular training of employees. Otherwise, the positive effect wears off quickly. Nevertheless, we could show that the stringent application of quality tools can induce a sustainable change. Our data further suggest that the clear and traceable delegation of responsibilities is of high importance.

Combined suture and clipping for the reconstruction of a ruptured blister-like aneurysm.

Blister-like aneurysms of the internal carotid artery (ICA) present a severe therapeutical challenge. While several reconstructive techniques are in use in case of acute rupture sacrifice of the parent vessel may be required. We present a combined technique of micro-sutures and clip application to repair the parent vessel in an intraoperatively ruptured blister-like aneurysm. Following temporary trapping of an intraoperatively ruptured 7-mm blister-like aneurysm four 8-0 nylon sutures were applied to adapt the vessel walls and support the branches of subsequently applied mini-clips. The combination of micro-sutures and mini-clips might be a valuable alternative to direct clipping or suturing in some cases with intraoperative rupture of blister-like aneurysms.

Suicidal ideation, depression, and health-related quality of life in patients with benign and malignant brain tumors: a prospective observational study in 83 patients.

OBJECTIVE: Health-related quality of life (HRQoL) and psychosocial burden are of relevance in patients with intracranial tumors. We investigated the prevalence of suicidal ideation (SI), depression, and their association with HRQoL in patients with intra- (IA) and extraaxial (EA) tumors during the first 9 months after diagnosis. METHODS: Patients were recruited immediately following surgery, and re-evaluated after 3, 6, and 9 months (EORTC QLQ-C30/BN20, Beck Depression Inventory (BDI) and Appendix). Patients with a personal history of psychological comorbidity were excluded. Sociodemographic and clinical data were evaluated. RESULTS: IA patients had lower functioning scores and experienced more symptoms. Global Health Status was significantly lower at baseline (p = 0.038), but improved over time (p < 0.001). Seventeen patients (21.5 %) admitted to having had SI at least once during the study period (IA: n = 10/EA: n = 7). The highest rates were observed after 6 (IA: 18.8 %) and 9 months (EA: 10.0 %). Patients reporting SI had significantly higher BDI scores [p = 0.22 (baseline), p = 0.031 (3 months), p < 0.001 (6 months)]. After 6 months, HRQoL differed greatest between patients with and without SI. Most patients experienced good familial support (76 %). CONCLUSIONS: Patients with intracranial tumors suffer from decreased HRQoL and SI regardless of histopathology. SI is associated with higher BDI scores, but not evident depression (BDI ≥ 18). Thus, patients should be screened specifically and regularly. Lower HRQoL and greatest prevalence of SI at 6 months may help clinicians to find the right time for careful monitoring of patients at risk.

Adjuvant temozolomide-based chemoradiotherapy versus radiotherapy alone in patients with WHO III astrocytoma: The Mainz experience.

BACKGROUND: It is currently unclear whether adjuvant therapy for WHO grade III anaplastic astrocytomas (AA) should be carried out as combined chemoradiotherapy with temozolomide (TMZ)--analogous to the approach for glioblastoma multiforme--or as radiotherapy (RT) alone. PATIENTS AND METHODS: A retrospective analysis of data from 90 patients with AA, who were treated between November 1997 and February 2014. Assessment of overall (OS) and progression-free survival (PFS) was performed according to treatment categories: (1) 50%, RT + TMZ according to protocol, (2) 11%, RT + TMZ with dose reduction, (3) 26%, RT alone, and (4) 13%, individualized, primarily palliative therapy. No dose reduction was necessary in the RT alone group. RESULTS: Median OS was 85, 69, and 43 months for treatment categories 1/2, 3, and 4, respectively. These differences were not statistically significant. PFS was 35, 29, 48, and 33 months for categories 1, 2, 3, and 4, respectively; again without significant differences between categories. In a subgroup of 39 patients with known IDH1 R132H status, the presence of this mutation correlated with significantly longer OS (p = 0.01) and PFS (p = 0.002). Complete or partial tumor resection and younger age also correlated with a significantly better prognosis, and this influence persisted in multivariate analysis. In the IDH1 R132H subgroup analysis, only this marker retained an independent prognostic value. DISCUSSION AND CONCLUSION: A general superiority of combined chemoradiotherapy compared to RT alone could not be demonstrated. Biomarkers for predicting the benefits of combination therapy using RT and TMZ are needed for patients with AA.

Strong adverse prognostic impact of hyperglycemic episodes during adjuvant chemoradiotherapy of glioblastoma multiforme.

BACKGROUND: In comparison to normal brain tissue, glioblastomas exhibit significantly increased glucose uptake. Brain edema is a common complication during adjuvant chemoradiotherapy, leading to a requirement for glucocorticoid treatment. Glucocorticoid treatment frequently causes considerable deregulation of blood glucose levels. Therefore, episodes of hyperglycemia may contribute to radio- and/or chemoresistance. PATIENTS AND METHODS: This study comprises a retrospective analysis of the influence of hyperglycemic episodes (HEs) during adjuvant therapy on the overall survival of 106 glioblastoma multiforme patients. RESULTS: The occurrence of one or more deregulated blood glucose value(s) > 10 mM is associated with a reduction in median overall survival from 16.7 to 8.8 months. A significantly poorer overall survival of patients with hyperglycemia could also be detected in subgroup analyses of patients with complete tumor resection and complete treatment according to the EORTC 22891/26891 trial protocol, as well as in a multivariate Cox proportional hazards analysis. A history of diabetes mellitus had no influence on prognosis. DISCUSSION: Our data suggest that the observed negative impact of elevated blood glucose levels on overall survival may not solely be explained by the patients' poorer general condition; the elevated blood glucose concentration itself may play a pathogenetic role. This could be due to increased activity of antioxidant systems, elevated expression of DNA damage response proteins and protection of hypoxic tumor cells against apoptosis combined with hypoxia-mediated radioresistance. CONCLUSION: A possible prognostic impact of elevated blood glucose levels during the period of adjuvant (chemo-) radiotherapy of glioblastoma should be evaluated in a prospective clinical trial.

C-OnSite ® for intraoperative 3D control of pedicular screw positions.

BACKGROUND: Two-dimensional image guidance and navigation can help to reduce the number of misplaced pedicle screws, but do not completely prevent misplacement. This experimental, retrospective, non-inferiority study was designed to evaluate and compare the efficacy of a novel 3D imaging technique versus conventional postoperative CT-scan, for intra-operative determination of pedicle screw position accuracy. METHODS: The capacity of C-OnSite® to intraoperatively assess screw placement was evaluated in 28 clinical cases and 23 deliberately misplaced screws in a cadaver model, and compared to placement accuracy determined by standard CT. The position of each implant, as viewed by both modalities, was graded by three neurosurgeons, one orthopaedic-surgeon and one radiologist. The intermodal variance determined the difference between CT- and C-OnSite® results for each observer, while the inter-observer variance measured the difference between ratings of the same modality by different observers. RESULTS: C-OnSite® successfully assessed 120/138 screws (25/28 cases). Mean procedural fluoroscopy time was 132 ± 51 s, and 40 ± 16s per C-OnSite® scan. The average inter-modality variance was ,15 % with mismatches >1° between C-OnSite® and the gold-standard imaging technique in only 2 % of the comparisons. Average inter-observer variances were about similar (12 % for CT and 18 % for C-OnSite®), with deviations of >1° reaching 1 % for CT and 3 % for C-OnSite®. Individual variances between experienced only observers differed even less. CONCLUSIONS: C-OnSite® is a feasible, reliable and intuitive means of intraoperatively visualizing pedicle screw positions and might render the majority of postoperative CTs superfluous. C-OnSite® might help avoid re-operations for screw re-positioning.

Image-guided implantation of pre-calibrated catheters in the ICU: a feasibility study.

BACKGROUND: Image-guided implantation of intracranial catheters is a routine procedure. Although time for surgery is short, transport from the intensive care unit (ICU) to the operation room (OR) is time-consuming and endangers patients in vulnerable intracranial pressure phases. Unfortunately, technical aspects of image guidance have so far required surgery to be performed in the operation room. In this observational study we investigated the feasibility of image-guided catheter placement in the ICU using a pre-calibrated stylet for implantation of intracranial catheters for a variety of indications and compare the results of procedures performed in the OR. METHODS: Twenty-three patients received implantation of 31 image-guided intracranial catheters or external ventricular drains using a pre-calibrated stylet in the ICU or in the OR. The times required for navigation planning, transport and surgery were assessed. Pre-operative trajectory planning, intra-operative screenshots of the navigation system and postoperative computed tomography (CT) scans were compared. RESULTS: Eleven external ventricular drains and nine intracranial catheters for fibrinolytic therapy of intracerebral haemorrhage were implanted in the OR, whereas ten external ventricular drains and one catheter for fibrinolytic therapy were implanted in the ICU. All catheters implanted on the ICU, 81.8 % of external ventricular drains and 88.8 % of lysis catheters placed in the OR had an optimal position to function. CONCLUSION: A pre-calibrated stylet in combination with the flexible headband equipped with reference arrays allows the application of image guidance in the ICU. It reduced time expended for patients and employees, and avoided the risks of ICU transport to the OR.

Concurrent Activation of Both Survival-Promoting and Death-Inducing Signaling by Chloroquine in Glioblastoma Stem Cells: Implications for Potential Risks and Benefits of Using Chloroquine as Radiosensitizer.

Lysosomotropic agent chloroquine was shown to sensitize non-stem glioblastoma cells to radiation in vitro with p53-dependent apoptosis implicated as one of the underlying mechanisms. The in vivo outcomes of chloroquine or its effects on glioblastoma stem cells have not been previously addressed. This study undertakes a combinatorial approach encompassing in vitro, in vivo and in silico investigations to address the relationship between chloroquine-mediated radiosensitization and p53 status in glioblastoma stem cells. Our findings reveal that chloroquine elicits antagonistic impacts on signaling pathways involved in the regulation of cell fate via both transcription-dependent and transcription-independent mechanisms. Evidence is provided that transcriptional impacts of chloroquine are primarily determined by p53 with chloroquine-mediated activation of pro-survival mevalonate and p21-DREAM pathways being the dominant response in the background of wild type p53. Non-transcriptional effects of chloroquine are conserved and converge on key cell fate regulators ATM, HIPK2 and AKT in glioblastoma stem cells irrespective of their p53 status. Our findings indicate that pro-survival responses elicited by chloroquine predominate in the context of wild type p53 and are diminished in cells with transcriptionally impaired p53. We conclude that p53 is an important determinant of the balance between pro-survival and pro-death impacts of chloroquine and propose that p53 functional status should be taken into consideration when evaluating the efficacy of glioblastoma radiosensitization by chloroquine.

Management of C2 fractures using Iso-C(3D) guidance: a single institution's experience.

BACKGROUND: About 20 % of cervical fractures involve the C2 vertebra. Many surgical techniques have been proposed according to the type of fracture. However, morbidity and mortality of these procedures is often high, which can be attributed to the old age and significant co-morbidities of the affected population and the complex anatomy of C2. To target the latter, several authors have applied iso-C(3D) guidance for most of the common techniques. We here present our experience using a fixed protocol and iso-C(3D) guidance in all cases of traumatic C2 fractures. METHODS: Sixteen patients were operated upon between April 2011 and April 2012 using Iso-C(3D) guidance, following a fixed routine protocol. The screw position was verified by CT-scanning. Intraoperative and clinical parameters were evaluated. RESULTS: Six patients received anterior lag-screw fixation of odontoid fractures. Two underwent isolated posterior lag-screw fixation of hangman's fracture. C1 and/or C3 lateral mass, and/or C2 isthmic screws were placed in eight patients. No screw had to be revised, 3 minor breachings of the cortical bone of <2 mm were observed.The same standard protocol for draping, registration of the navigation and Iso-C(3D) guided drilling could be applied for anterior and posterior procedures, leaving only two variables. This led to rapid acceptance of the technique among OR-staff and surgeons, who felt comfortable with iso-C(3D) guidance after only five cases. CONCLUSIONS: Iso-C(3D) guidance is a safe and straightforward technique for anterior and posterior screw placement in the upper cervical spine.