Caliper navigation for craniotomy planning of convexity targets.

IntroductionA technique to localize a radiological target on the head convexity fast and with acceptable precision is sufficient for surgeries of superficial intracranial lesions, and of help in the setting of emergency surgery, computer navigation breakdown, limited resources and education. We present a caliper technique based on fundamental geometry, with inexpensive and globally available tools (conventional CT or MRI image viewer, calculator, caliper).MethodsThe distances of the radiological target from two landmarks (nasion and porus acusticus externus) are assessed with an image viewer and Pythagoras' theorem. The two distances are then marked around the landmarks onto the head of the patient with help of a caliper. The intersection defines the target. We tested the technique in a saw bone skull model and afterwards in the operating room. Convexity targets were localized with the caliper navigation technique and then with computer navigation as ground truth.ResultsIn the saw bone model, the mean offset between the caliper navigated target and the real target was 2.9 ± 2.8 mm, 95% CI (1.6 mm; 4.2 mm). The mean offset between computer navigated target and real target was 1.6 ± 0.9 mm, 95% CI (1.2 mm; 2 mm) (ns). In 15 patients undergoing navigated cranial procedures, 100 targets were assessed in reference to computer navigation. The mean offset of the caliper navigation was 11 ± 5.2 mm, 95% CI (9.9 mm; 12 mm).ConclusionThis is a low-tech approach for translation of a radiological target to the patient's head in short time and with globally available inexpensive tools, with satisfying precision for many procedures

Clipping of ruptured intracranial aneurysms in a hybrid room environment-a case-control study

BACKGROUND Hybrid room treatment (HRT) provides the surgeon immediate intraoperative angiography control of aneurysm occlusion and vessel patency. Since it is relatively resource demanding, in clinical routine HRT is reserved for elective cases. However, since its introduction in our department in 2008, several random cases of ruptured intracranial aneurysms (IAs) have been treated in the HR. This study aims to compare the clinical and radiological outcomes of these cases with cases treated conventionally using a matched pair analysis. METHODS Twenty (20%) consecutive patients with ruptured IA treated by microsurgical clipping in the HR between 2009 and 2015 were retrospectively matched with "conventionally" (C) treated patients (overall n = 101). Clinical and radiological outcome variables were assessed and compared. RESULTS Despite a trend in favor of the HR group, no significant difference between both matched groups (HR vs. C) could be demonstrated regarding the functional outcome (upper/lower good recovery 16/20 vs. 17/20, p > 0.05), frequency of clipping-related vascular insults on CT scans (0/20 vs. 3/20, p > 0.05), aneurysm remnant rate on postoperative angiography (1/20 vs. 4/20, p > 0.05) and retreatment rate (0/20 vs. 1/20, p > 0.05). When cumulating all outcome events by a scoring system, however, the HR cohort showed a significantly lower occurrence of events (p < 0.05). In three cases co-treatment by an endovascular approach was performed in the HR cohort. CONCLUSION In this relatively small cohort, a matched pair analysis revealed a discrete but not significant tendency toward a lower frequency of aneurysm remnants and clipping-related vascular insults in the HR cohort. However, HR cohort patients benefited from direct endovascular co-treatment in selected cases

Clival chordoma: a single-centre outcome analysis.

BACKGROUND The treatment of clival chordomas remains challenging. Total tumour resection is often impossible without hampering adjacent anatomical structures and causing functional sequelae. On the other hand, chordomas show limited response to non-surgical treatment modalities. Up to now, no well-established interdisciplinary treatment algorithms for clival chordomas exist. In this regard, we analysed the data from all patients that underwent interdisciplinary treatment for clival chordoma in our institution over the last 10 years. METHOD Retrospective report of all patients treated at the authors' institution from 2005 to 2015. RESULTS Thirteen patients underwent 24 surgeries, of which 2 (8%) were gross total resections and 22 (92%) incomplete resections. Neurological deterioration, endocrinological disturbances and other surgical complications were observed in six (25%), three (13%) and nine (38%) cases, respectively. Three surgeries (13%) led to an improvement of the initial preoperative neurological condition. All patients were discussed on the interdisciplinary tumour board and all underwent one type of radiotherapy following initial surgery: proton beam in 11 cases (85%) and photon beam in two (15%) cases. In the course of their recurrent disease, three patients (23%) received systemic therapy (imatinib, pazopanib and nivolumab). One patient received a personalised cellular immunotherapy. One patient (8%) was lost to follow-up. Of the remaining 12 patients, four patients (33%) died in the period of analysis; all deaths were chordoma-related. The 5-year cumulative survival rate was 83% (52-97%, CI 95%), 5-year progression-free survival rate was 53% (26-79%, CI 95%). The eight patients (66%) still alive had favourable outcome (KPS, 90 ± 10.7%). SF36 analysis among the survivors revealed 43 points for the Physical Component Summary (12% above, 38% at and 50% below the general population norm) and 47 points for the Mental Component Summary (25% above, 38% at and 38% below). CONCLUSIONS Our patients show a low rate of gross total resection but an outcome well comparable to other published results. This emphasises the importance of interdispiplinary treatment strategies, with surgery supplying maximal safe resection and avoiding severe neurological deficit, allowing patients to undergo adjusted radiotherapy and other treatment options in a good condition

Quantification of Working Volumes, Exposure, and Target-Specific Maneuverability of the Pterional Craniotomy and Its Minimally Invasive Variants

OBJECTIVE: Quantitative comparison of minimally invasive and standard cranial approaches remains a methodologic challenge. The aim of this study was to apply a new digital, navigation-based method to quantify multiple parameters of the pterional, supraorbital, lateral supraorbital and mini-pterional approaches and to describe a target-specific maneuverability score. METHODS: Supraorbital, lateral supraorbital, mini-pterional, and standard pterional craniotomies were performed on 8 sides in 4 cadaver heads. The limits of superficial and deep exposure and surgical target points were registered with image-guidance (Medtronic Stealth). A custom software (Guided Therapeutics Eyes II Software [GTxEyesII]) calculated superficial and deep surface areas, working volumes, and target distances. Volumes were reconstructed digitally and visualized with GTxEyesII. Finally, we defined for each approach a target-specific maneuverability score based on surface exposure, target distance, target position, and anatomical obstacles. RESULTS: Surface exposure and volumes were significantly smaller for keyhole approaches compared with standard pterional craniotomy (P < 0.01). Maneuverability index scores showed the greatest values for standard pterional craniotomies, but nearly equally high scores could be achieved by one or several of the less-invasive approaches for most of the targets. CONCLUSIONS: The combination of a navigation-based measurement method with custom software (GTxEyesII) provides a powerful tool for visualization and quantification of surgical approaches. Compared with standard pterional craniotomy, alternative keyhole craniotomies offer comparable deep exposure with smaller working volumes and relatively high maneuverability for specific targets

Unruptured intracranial aneurysm follow-up and treatment after morphological change is safe: observational study and systematic review

The management of small unruptured incidentally discovered intracranial aneurysms (SUIAs) is still controversial. The aim of this study is to assess the safety of a management protocol of SUIAs, where selected cases with SUIAs are observed and secured only if signs of instability (growth) are documented

Correlating Clinical Risk Factors and Histological Features in Ruptured and Unruptured Human Intracranial Aneurysms: The Swiss AneuX Study

Pathogenesis of intracranial aneurysm is complex and the precise biomechanical processes leading to their rupture are uncertain. The goal of our study was to characterize the aneurysmal wall histologically and to correlate histological characteristics with clinical and radiological factors used to estimate the risk of rupture. A new biobank of aneurysm domes resected at the Geneva University Hospitals (Switzerland) was used. Histological analysis revealed that unruptured aneurysms have a higher smooth muscle cell (SMC) content and a lower macrophage content than ruptured domes. These differences were associated with more collagen in unruptured samples, whereas the elastin content was not affected. Collagen content and type distribution were different between thick and thin walls of unruptured aneurysms. Classification of aneurysm domes based on histological characteristics showed that unruptured samples present organized wall rich in endothelial and SMCs compared with ruptured samples. Finally, aneurysm wall composition was altered in unruptured domes of patients presenting specific clinical factors used to predict rupture such as large dome diameter, dome irregularities, and smoking. Our study shows that the wall of aneurysm suspected to be at risk for rupture undergoes structural alterations relatively well associated with clinical and radiological factors currently used to predict this risk

Sex‐Dependent Manifestations of Intracranial Aneurysms

BACKGROUND Intracranial aneurysms (IAs) are more common in women than in men; however, there is still limited knowledge on sex‐dependent differences regarding aneurysm location, multiplicity, rupture risk, risk factors, and histopathology. METHODS This cross‐sectional, consecutive cohort study examined whether IAs differ in multiplicity, location, geometry, rupture risk, risk factors, and histology between sexes. RESULTS We included 982 patients (714 women, 268 men) totaling 1484 IAs (1056 unruptured, 397 ruptured). A total of 363 patients (36.97%) had multiple IAs, the proportion of which was significantly higher in women. In women, the internal carotid artery (40.79%) was the most frequent location for IAs, whereas in men most were found along the anterior carotid artery territory (32.86%). Men were significantly more often diagnosed with ruptured aneurysms. Aneurysm geometry did not differ between sexes; however, ruptured aneurysms in men presented with a significantly larger neck diameter than unruptured ones. Regarding risk factors for aneurysm rupture, blood pressure control was more effective in women, whereas the effect of smoking status did not show clear sex‐dependent differences. Histologically, wall‐type classification analysis showed significantly more severe aneurysm wall types in men. CONCLUSION IA prevalence in women is significantly higher than in men. Women more often present with multiple IAs, whereas men were more often diagnosed with ruptured IAs. Sex‐specific differences in IA location were identified, whereas geometry of IAs did not differ between sexes. IAs in men showed a more severe histological wall type. Further research is needed to unravel the molecular mechanisms underlying these important sex‐dependent manifestations in IAs.</p