Littérature scientifique sur le sujet « MED/27 - NEUROCHIRURGIA »

Background. Brain retraction plays an important role in the cranial surgery, but the problems that can arise from excessive retraction are not negligible. The major limitation to the use of brain retractors is their high possibility of parenchyma’s damage: this becomes particularly evident in interventions of many hours that require a long-lasting spatulation. Possible lesions from cerebral retraction can include contusions, hematomas and haemorrhages that can also affect patient's outcome. Project Objectives. The first our goal was to study the instruments currently present for cerebral retraction by analysing their advantages and disadvantages. After this, the main objective was to create a new brain retraction tool and validate its use in cranial surgery. Another objective was to exploit endoscopic vision also in transcranial surgery designing work chambers perfectly suitable for introducing the endoscope easily while providing safe retraction for the surrounding brain. To achieve these results, it was therefore necessary to carry out an accurate preclinical phase study which also benefits from collaboration of a multidisciplinary team. Research activity and novelty of the project. The careful study of this topic, the anatomical and engineering laboratory tests, have made it possible to create new technological tools with many advantages in the neurosurgical field. The dynamic mechanical characterization of the brain allows to predict the mechanical behaviour of the human brain in health and disease also being able to foresee and possibly avoid complications for patients. Due to the continuous technological progress in the neurosurgery field, today the need to understand the correlation between the material structure and related viscoelastic properties is becoming ever more crucial also in order to develop design guidelines for the next generation of biomaterials, to match tissue and extra cellular matrix mechanics for in vitro tissue models and applications in regenerative medicine. Conclusions and future perspectives. The knowledge of the behaviour of the brain parenchyma in response to a compression force is therefore important in order to understand the mechanisms underlying the damage, the dangerous thresholds and therefore the possible prevention of brain complications. This last aspect was fundamental to be able to create new "intelligent" surgical instruments that operate safely. We therefore performed tests on preclinical model, on specimens and then also on animals; we finally studied the brain parenchyma from the histological point of view, documenting the visible damage of the cerebral retraction. These phases were essential to then proceed with clinical phase on patients: the next steps will be to test the prototyped spatula on patient in the surgical theatre and finish the last preclinical tests of the chamber. We also hope to file the patent for the new spatula by the end of this year.
Background. La retrazione cerebrale svolge un ruolo importante nella chirurgia cranica, ma i problemi che possono derivare da un'eccessiva retrazione non sono trascurabili. Il principale limite all'uso dei divaricatori cerebrali è la loro elevata possibilità di danno del parenchima: questo diventa particolarmente evidente negli interventi di tante ore che richiedono una retrazione di lunga durata. Possibili lesioni da retrazione cerebrale possono includere contusioni, ematomi ed emorragie che possono anche influenzare l’outcome del paziente. Obiettivi del progetto. Il primo nostro obiettivo era quello di studiare gli strumenti attualmente presenti per la retrazione cerebrale analizzandone vantaggi e svantaggi. Successivamente, l'obiettivo principale era creare un nuovo strumento di retrazione cerebrale e convalidarne l'uso nella chirurgia cranica. Un altro obiettivo era quello di sfruttare la visione endoscopica anche nella chirurgia transcranica progettando camere di lavoro perfettamente adatte per introdurre facilmente l'endoscopio fornendo al contempo una retrazione sicura per il cervello circostante. Per raggiungere questi risultati è stato quindi necessario condurre un accurato studio in fase preclinica con la collaborazione di un team multidisciplinare. Attività di ricerca e novità del progetto. L'attento studio di questo argomento, i test eseguiti in laboratorio di anatomia e di ingegneria, hanno permesso di creare nuovi strumenti tecnologici con molti vantaggi in campo neurochirurgico. La caratterizzazione meccanica dinamica del cervello permette di predire il comportamento meccanico del cervello umano sano e malato potendo anche prevedere ed eventualmente evitare complicanze per i pazienti. Grazie al progresso tecnologico nel campo della neurochirurgia, oggi la necessità di comprendere la correlazione tra la struttura del materiale e le relative proprietà viscoelastiche sta diventando sempre più cruciale anche al fine di sviluppare linee guida progettuali per la prossima generazione di biomateriali, per abbinare tessuti ed extra meccanica della matrice cellulare per modelli tissutali in vitro e applicazioni nella medicina rigenerativa. Conclusioni e prospettive future. La conoscenza del comportamento del parenchima cerebrale in risposta ad una forza di compressione è quindi importante per comprendere i meccanismi alla base del danno, le soglie pericolose e quindi la possibile prevenzione delle complicanze cerebrali. Quest'ultimo aspetto è stato fondamentale per poter realizzare nuovi strumenti chirurgici “intelligenti” che operino in sicurezza. Abbiamo quindi eseguito test su modellino preclinico, su cadavere e poi anche su animale; abbiamo infine studiato il parenchima cerebrale dal punto di vista istologico documentando il danno visibile causato dalla retrazione cerebrale. Questi steps sono stati fondamentali per poi procedere con la fase clinica sui pazienti: i prossimi passi saranno testare il prototipo della spatola sul paziente in sala operatoria e terminare gli ultimi test preclinici della camera. Confidiamo anche di depositare il brevetto per la nuova spatola entro la fine di quest'anno

Background Learning and straightening of surgical techniques requires continuous training that cannot overlook from lab activities. During microsurgery, specific bimanual abilities are necessary to perform perfect vessels dissection and anastomosis. In this scenario, the development of realistic training models is utmost important. Objective The aim of this research is to describe a detailed method of preparation of a dye-perfused human placenta training model and its application during microsurgical hands-on courses. An original description of training exercises has been reported. Moreover, a review of the literature on this topic has been performed. Methods Forty-five fresh human placentas were collected and prepared with a specific protocol. The model was used during four hands-on microsurgical training courses held in the Experimental Laboratory of Microsurgery “Botta 2” of the University of Pavia, Italy. The total number of participants was 40 divided into young specialists and residents of Neurosurgery, Otolaryngology and Maxillofacial surgeons. An on-line survey-based questionnaire, using the platform SurveyMonkey®, was administered to each participant to subjectively assess face and content validity of the proposed training model. Differences in categorical responses between groups were analyzed using chi-quadro (χ2) test for independence with STATA® 16 (StataCorp LLC) software. A comprehensive literature review of articles regarding the use of human placenta as a microsurgical training model was performed via multiple PubMed database searches. Results Forty-two of 45 placentas were considered appropriate for microsurgical model. In selected placentas, the arteries could be easily distinguished from the veins and all three vessels were cannulated and perfused with dyes. The model was used to perform vessels dissection and end-to-end, end-to-side and side-to-side anastomosis. Of the 40 course attendees, 33 completed the questionnaire, of which most indicated the placenta as a valuable, accurate, and reproducible model. No differences were observed among the groups. Conclusion The proposed model is an excellent tool for vascular microsurgical laboratory training. A standardized protocol makes its preparation easier and color perfusion enhances its reliability. The low-cost, accessibility, and the variety of size and number of placental vessels are the most important advantages of such polyhedral model, useful for several specialized surgical fields. Due to the possibility of choosing exercises with different degrees of difficulty, this model perfectly matches the philosophy of microsurgical practice. The application of rating scale that allow to verify the teaching efficacy of this training model represents the future step of this research.

Meningiomas are considered a substantially benign disease that can be treated surgically in the vast majority of patients. However, there are forms of meningioma characterized by greater aggressiveness and/or tendency to recurrence. To date, grading is the only known factor that provides some information about the biological behavior of meningiomas. As a matter of fact, patients with high grade meningiomas (WHO grade 2 and 3) have a significant higher risk to develop local recurrence after treatment and, consequently, they tend to have a shorter survival compared to patients with WHO grade 1 meningiomas .However, even grade 1 meningiomas can recur even if with less frequency. Given that to date there are no approved pharmacological treatments for meningiomas and that the use of treatments such as hormone-therapy and chemotherapy have not shown any substantial benefit, it seems appropriate to hypothesize new innovative therapeutic strategies and verify their biological plausibility. To our knowledge, this is the first report of increased PD-L1 expression in meningioma recurrences compared to their primary presentation, regardless of their grade. The high prevalence of PD-L1 expression in the meningioma population and its correlation with grade and clinical behavior may be an important tool to tailor therapeutical strategies and follow up, in particular in high grade and recurrent cases. Moreover, the results obtained contribute to build a rational basis for designing therapeutic trials that use immunotherapy in the treatment of meningiomas.

The principal aim of the candidate’s course was to advance in the skills of research in the complex and evolving context of therapeutic strategies for medical refractory epilepsy in pediatric age. As a neurosurgeon graduate and consultant, part of a neurosurgical department, the candidate work consisted in two principal field of clinical practice-derived research: surgical treatment of hemispheric epilepsy in young infants and MRI- guided interstitial laser thermotherapy (MRg-LiTT) for refractory epilepsy of different origin. Hemispheric surgery is a subject of great interest as it represents an effective option for severe forms of epilepsy with high neurological morbidity, linked to developmental delay and that could be life-threatening, especially in very young infants. Studies focusing on first infancy are rare and more data are needed in literature. The second topic represents an important innovation in the Giannina’s Gaslini neurosurgical treatment offer. MRg-LiTT is a novel approach for the cure of refractory epilepsy, especially linked to hypothalamic hamartomas, with a significant shift in benefit-risk ratio, giving the opportunity to lower the high neurological morbidity linked to more traditional open-surgery approaches. The technique consists in the stereotactic introduction of a laser diode fiber inside a cerebral epileptogenic region (e.g. hypothalamic hamartomas, tuberous sclerosis, cavernomas, seizure onset zones), that is ablated by the high temperature delivered at the tip of the catheter, protecting the important surrounding structures using a near real-time MRI thermography technology.

One of the main aims of awake surgery for glioma patients is to preserve quality of life, while maximizing tumor resection. Focusing on an important yet understudied aspect of quality of life, this thesis investigates to what extent written language may be affected by a glioma or glioma surgery. By reviewing current assessments of reading and spelling in awake surgery studies, we aimed to provide a better understanding of how neuroanatomical theories may guide neurosurgical practice, and to evaluate how examinations of written language in glioma patients can be improved. To provide a direct clinical application for this knowledge, we developed a theory-driven written language battery specifically for glioma patients. Lastly, we tested its efficacy and evaluated reading and spelling performance in neurosurgical practice. The studies in this thesis have provided a better understanding of written language in neurosurgical practice. In particular, it has contributed to prediction and prevention of written language disorders in glioma patients undergoing awake surgery, and it has resulted in a valid examination tool to carefully monitor reading and spelling in this patient group.

Early activation of inflammation in an experimental model of subarachnoid hemorrhage Introduction. There is increasing evidence that inflammation plays a critical role in the pathogenesis of vasospasm and delayed ischemic deficits after Subarachnoid Hemorrhage (SAH). Objective. Aim of this study is to evaluate the early activation of inflammatory response at the level of basilar artery in a model of single hemorrhage in rats. Material and Methods. A single hemorrhage model was used. CD-IGS rats (250-350 gr) were anesthetized using an i.p. administration of ketamine (100mg/Kg) and midazolam (1 mg/Kg) and subcutaneous fentanyl (0.0075 mg) to control pain. In SAH group, subarachnoid hemorrhage was induced by injection of autologous arterial blood into the cisterna magna of the animal throughout a suboccipital puncture (200 µl in 3 min). Animals were therefore maintained with the head down for 15 minutes and were leaved to breath autonomously and to recover. In Sham group, rats were submitted to the same procedures, puncturing the cisterna magna, without injecting arterial blood in it. In basal group, rats were not submitted to any surgical procedure. In short term experiments, animals were sacrificed 4 hours after the puncture. Basilar artery was then removed from the rat brain and freezed. A pool of 3 arteries were necessary in order to obtain adequate amount of RNA to perform gene expression analysis. 4 pool of arteries for each group was submitted to a real-time PCR analysis to evaluate expression of the following genes: TNF-α, IL-6, CXCL-1, iNOS, ET-1, ICAM-1. 3 pools of arteries for each group were submitted to TaqMan Low Density Array. TaqMan Low Density Array is a consumable consisting of 384 wells connected by a series of microfluidic channels, designed to be used on the Applied Biosystems 7900HT Fast Real-Time PCR System platform. Microfluidic technology allows multiple targets to be analyzed across many samples simultaneously. These arrays are used to analyze specific biological pathway activation and the expression of genes of interest. In this work, 90 genes of interest related to the inflammatory response, oxidative stress, repair mechanisms and apoptosis, and 7 genes of reference were analyzed. In long term experiments, rats were divided in 2 groups: SAH group and basal group. In SAH group, animals were sacrificed 5 days after procedure or at the occurrence of any clinical disturbances. At sacrifice animals were perfused with isotonic phosphate-buffered saline (PBS) and fixed with paraformaldehyde. Brain was therefore removed and freezed in a solution of OCT, isopentane and liquid nitrogen. Section of 20 m were performed in the brain stem of the rats, in order to complete a morphometric analysis (diameter, area, thickness) of the basilar artery at three levels. Results. Preliminary analysis of genes expression with RT-PCR showed the early up-regulation of all genes in the SAH group: TNF-α (SAH 3.2, SHAM 2.2, CONTROL 1.1), IL-6 (SAH 343, SHAM 2, CONTROL 1); CXCL-1 (SAH 187, SHAM 42, CONTROL 1), iNOS (SAH 39, SHAM 2, CONTROL 0), ET-1 (SAH 2.6, SHAM 1.2, CONTROL 1.1), ICAM-1 (SAH 5.1, SHAM 1.8, CONTROL 1.1). Subsequent analysis with Taqman Low Density array allowed to confirm the clear differentiation of the SAH group with respect to the basal and SHAM groups (p=0.0370). With the assistance of the software EASE, the analysis was deepened in order to evaluate the hypothetic modulation of molecular processes in SAH group. This demonstrated an up-regulation of genes involved in different aspects of immune response, response to stress or external stimulus, and tissue repair, while genes coding for structural protein of intercellular junction or localized at the level of cell membrane are down-regulated. Morphometric analysis in long-term experiments showed the reduction of basilar artery diameter and area in the SAH group (55 ± 15 microm vs 91 ± 20 microm and 1381 ± 150 microm2 vs 3898± 214 microm2). Conclusions These results show an early expression of genes involved in inflammatory process on the wall of the intracranial vessels exposed to subarachnoid blood injection in a model of single hemorrhage in rats. This seems to confirm that inflammation plays a crucial role in the cascade of events after SAH, leading to vasospasm and delayed ischemic deficits, and suggests that new treatments capable to modulate this response could eventually be beneficial.

One of the main aims of awake surgery for glioma patients is to preserve quality of life, while maximizing tumor resection. Focusing on an important yet understudied aspect of quality of life, this thesis investigates to what extent written language may be affected by a glioma or glioma surgery. By reviewing current assessments of reading and spelling in awake surgery studies, we aimed to provide a better understanding of how neuroanatomical theories may guide neurosurgical practice, and to evaluate how examinations of written language in glioma patients can be improved. To provide a direct clinical application for this knowledge, we developed a theory-driven written language battery specifically for glioma patients. Lastly, we tested its efficacy and evaluated reading and spelling performance in neurosurgical practice. The studies in this thesis have provided a better understanding of written language in neurosurgical practice. In particular, it has contributed to prediction and prevention of written language disorders in glioma patients undergoing awake surgery, and it has resulted in a valid examination tool to carefully monitor reading and spelling in this patient group.

Abstract Introduction. The expansion of the endoscopic endonasal approach in neurosurgery during the last three decades recently led the neurosurgical clinical interest to the investigation of further application of this technique, namely to neurovascular pathologies. Cadaver dissections studies have represented the milestone in the progressive application of this technique. Integrating anatomical studies with advanced visualization tools and quantification methods increases their impact toward clinical application. Material and methods. The main endoscopic endonasal approaches were performed and exposure of the vascular intracranial structures was analyzed: the anterior communicating artery complex was investigated through the transplanum transtuberculum approach; the transsphenoidal approach to the sellar area was performed for the exposure of the intracavernous internal carotid artery; the basilar artery was exposed by means of the endoscopic endonasal transclival approach, and the vertebral arteries through the extended endonasal approach to the craniovertebral junction. Possible clinical application of each approach was investigated during anatomical dissections upgraded with imaging and quantification methods. Results. The transtuberculum transplanum approach allows for the exposure and control of the anterior communicating artery complex; the relationship between the proximal anterior cerebral artery, gyrus rectus, and optic chiasm is the main determinant for the exposure and control of the vessel. Temporary occlusion of the internal carotid artery with a Fogarty balloon catheter through the endoscopic transsphenoidal route might be another maneuver that is useful for obtaining intraoperative control of the vessel. The endoscopic transclival approach may be considered a minimally invasive route to the basilar apex in the presence of specific anatomical and pathological features. Comparative analysis of the anatomical exposure of the vertebro-basilar junction as obtained through transcranial and endoscopic endonasal approaches may be helpful in unlocking this complex skull base area. Conclusions. The introduction of the endoscopic endonasal approaches for the treatment of cerebrovascular pathologies represents the most advanced and innovative step forward of the skull base endoscopic endonasal surgical technique. The present PhD research activity may add relevant anatomical and clinical information to the rather sparse literature directly focused on surgical indication of the endoscopic endonasal approaches to vascular neurosurgery.

Introduzione. I cordomi della base cranica sono tumori rari e a lenta crescita derivanti dalla notocorda. La loro morbilità è principalmente legata alla loro invasione locale e alla resistenza ai trattamenti. A causa del loro aspetto eterogeneo e del loro comportamento clinico-molecolare non completamente compreso, l'obiettivo principale del presente lavoro è quello di identificare marcatori clinici e bio-molecolari come fattori prognostici specifici che potrebbero essere utilizzati per la corretta gestione di tali pazienti. Il raggiungimento di una firma prognostica dettagliata dei cordomi del basicranio è di fondamentale importanza per poter personalizzare il trattamento di ciascun paziente. Inoltre, l'analisi degli sfingolipidi sta emergendo come un nuovo approccio in molti tumori e non è mai stata applicata nei cordomi. L’obiettivo principale è lo studio del comportamento biologico del cordoma e il ruolo della produzione di ceramidi in questo contesto di proliferazione e invasione locale. Pazienti e Metodi. È stata eseguita una revisione retrospettiva di tutti i pazienti diagnosticati e trattati per cordoma della base cranica presso la Fondazione IRCCS Istituto Neurologico "Carlo Besta" tra il gennaio 1992 ed il dicembre 2017. Sono stati raccolti dati clinici, radiologici, chirurgici e patologici. È stata eseguita una raccolta prospettica di campioni chirurgici congelati per analizzare le specie di ceramidi. Gli sfingolipidi sono stati estratti dai tessuti congelati; i ceramidi e i diidroceramidi sono stati valutati mediante cromatografia liquida e spettrometria di massa. L'analisi di sopravvivenza è stata eseguita secondo il metodo di Kaplan-Meier. I confronti univariati sono stati condotti usando i test di Mann-Whitney, Chi-square e il test esatto di Fisher. Sono state condotte analisi di regressione e correlazione lineari. Utilizzando un modello di regressione logistica, i predittori statisticamente significativi sono stati pesati sulla base dei loro odds ratio al fine di sviluppare una scala personalizzata - la Peri-Operative Chordoma Scale (POCS). Risultati. Ottantasette pazienti sono stati trattati chirurgicamente per cordoma del basicranio. Settantotto pazienti sono stati dichiarati eleggibili per la revisione. I pazienti erano 38 maschi (48.7%) e 40 femmine (51.3%). Il follow-up medio era di 69 mesi (intervallo, 3-233). Sono stati eseguiti centoquattordici interventi chirurgici. La presenza di deficit motori si è rivelata essere un fattore prognostico significativo correlato a una PFS peggiore (p=0.0480). La presenza di calcificazioni ha mostrato una correlazione con risultati migliori di OS rispetto al tumore privo di calcificazioni (p=0.0420). Il grado di impregnazione contrastografica alla RM si è rivelato essere un fattore prognostico significativo in termini sia di OS che di PFS (p≤0.0001 e 0.0010, rispettivamente). Il coinvolgimento del forame giugulare e delle cisterne anteriori al tronco encefalico si sono rivelati due fattori prognostici significativi correlati con una riduzione di PFS (p=0.0130 e p=0.0210, rispettivamente). La dislocazione del tronco cerebrale rappresentava un fattore prognostico significativo correlato a peggiore OS e PFS nella coorte di cordomi recidivi (p=0.0060 e 0.0030, rispettivamente). L'estensione della resezione tumorale rappresentava un forte fattore prognostico secondo la PFS nella coorte di cordomi primari (p=0.0200). I pazienti operati da un chirurgo esperto (definito come il chirurgo che ha eseguito più di 10 procedure chirurgiche per cordoma del basicranio nella presente serie) hanno avuto un outcome migliore in termini di PFS nella coorte di pazienti primari (p=0.0340). Lo sviluppo di complicanze post-operatorie in pazienti con cordoma primario rappresentava un importante fattore prognostico correlato sia ad OS che a PFS (p≤0.0001 e 0.0360, rispettivamente). Nella coorte di cordomi recidivi, ∆KPS correlava sia a OS che a PFS (p=0.0010 e 0.0180, rispettivamente). Inoltre, il trattamento radioterapico postoperatorio correlava ad un aumento di OS e PFS (p=0.0020 e p=0.0100, rispettivamente). I seguenti fattori si sono rivelati predittori statisticamente significativi sia di PFS che di OS nel modello di regressione logistica: il grado di impregnazione contrastografica alla RM (intenso o lieve/nessuno), la presenza di deficit motori preoperatori (si o no) e lo sviluppo di complicanze post-operatorie (si o no). Una scala è stata sviluppata con score compresi tra 0 e 17 (Nagelkerke’s pseudo R2=0.656). Le specie totali di ceramidi e diidroceramidi nei cordomi primari erano 808.4±451.4 pmol/mg di proteine (522.5-1760.2) e 30.7±16.4 pmol/mg (17.6-62.4), rispettivamente. Le specie totali di ceramidi e diidroceramidi nei cordomi recidivi erano 1488.1±763.8 pmol/mg (540.7-2787.5) e 67.2±45.5 pmol/mg (9.0-145.6), rispettivamente. Le specie totali di ceramidi erano significativamente più elevate nei cordomi recidivi sottoposti a precedente resezione chirurgica e radioterapia rispetto ai cordomi primari (p=0.0496). Le specie totali di ceramidi e diidroceramidi nel gruppo "intensa impregnazione contrastografica" erano 1597.6±737.8 pmol/mg (592.7-2787.5) e 69.1±45.0 pmol/mg (17.8-145.6), rispettivamente. Le specie totali di ceramidi e diidroceramidi nel gruppo "nessuna o lieve impregnazione contrastografica" erano 664.7±120.4 pmol/mg (522.5-826.0) e 31.5±13.6 pmol/mg (17.6-53.6), rispettivamente. Ceramidi e diidroceramidi totali erano significativamente più alti nei cordomi ad “intensa impregnazione contrastografica” rispetto ai cordomi "nessun o lieve impregnazione contrastografica" (p=0.0290 e p=0.0186, rispettivamente). Analizzando l'associazione tra livelli di ceramidi e MIB-1 all'interno di ciascun paziente con cordoma della base cranica, i livelli di ceramidi totali hanno mostrato un'associazione forte (r=0.7257, r2=0.5267) con la colorazione MIB-1 (p=0.0033). Analizzando l'associazione tra i livelli di diidroceramidi e MIB-1 all'interno di ciascun paziente con cordoma della base cranica, i livelli totali di diidroceramidi hanno mostrato anche un'associazione forte (r=0.6733, r2=0.4533) con MIB-1 (p=0.0083). Tra le singole specie di ceramidi, Cer C24: 1 (r=0.8814, r2=0.7769, p≤0.0001), DHCer C24: 1 (r=0.8429, r2=0.7104, p=0.0002) e DHCer C18:0 (r=0.9426, r2=0.8885, p≤0.0001) hanno mostrato una correlazione significativa con il MIB-1. Conclusioni. L’analisi clinica ha dimostrato che la sintomatologia preoperatoria (deficit motori e a carico dei nervi cranici), la posizione anatomica (forame giugulare, dislocazione del tronco encefalico), le caratteristiche chirurgiche (estensione della resezione tumorale ed esperienza del chirurgo operatore), la presenza di complicanze postoperatorie e il declino del KPS si sono rivelati fattori prognostici significativi. Inoltre, il grado d’impregnazione contrastografica alla RM è stato significativamente correlato sia a OS che a PFS. È stata sviluppata in via preliminare la Peri-Operative Chordoma Scale (POCS) per aiutare il clinico nella gestione personalizzata del paziente che si sottoporrà a potenziali terapie adiuvanti. L’analisi di sfingolipidi, invece, ha evidenziato come i ceramidi possano rappresentare un promettente bio-marcatore nei cordomi. In particolare, i ceramidi a catena lunga e molto lunga, come Cer C24:1 e DHCer C18:0, possono concorrere ad una prolungata sopravvivenza del tumore, aggressività e l’effettiva comprensione del loro ruolo biologico potrà far luce sui possibili meccanismi di radio-resistenza, tendenza a recidivare del cordoma e allo sviluppo di agenti che possano avere come target il metabolismo dei ceramidi. Tali risultati dovrebbero essere validati in futuri studi clinici, in vitro e in vivo più ampi per confermare questo intricato legame tra il comportamento aggressivo del cordoma e dei ceramidi.
Introduction. Skull base chordomas are rare slow-growing neoplasms that arise from notochord. Their morbidity is mainly related to highly aggressive local invasion and resistance to treatments. Due to its heterogeneous appearance and not fully understood clinical and molecular behaviors, the main goal of the present work is to identify clinical and bio-molecular markers as specific prognostic factors that could be used for the management of skull base chordoma patients. Achieving a detailed prognostic signature of skull base chordomas is of paramount importance to personalize the treatment to each specific patient. Moreover, sphingolipids analysis is emerging as a new approach in many cancers and it has never been applied in chordomas. Our aim is to investigate chordoma biological behavior and the role of ceramides production in this context of proliferation and invasion. Patients and Methods. A retrospective review of all the patients diagnosed and treated for a skull base chordoma at the Fondazione IRCCS Istituto Neurologico “Carlo Besta” between January 1992 and December 2017 has been performed. Clinical, radiological, surgical and pathological data have been collected. A prospective collection of frozen surgical specimens has been performed to analyze ceramides species in chordomas. Sphingolipids were extracted from frozen tissues and total ceramides and dihydroceramides were evaluated by liquid chromatography and mass spectrometry. Survival analysis was performed according to Kaplan-Meier method. Univariate comparisons were conducted using Mann-Whitney, Chi-square and exact Fisher test. Simple linear regression and correlation with computation of Pearson coefficients analyses were conducted. Using a logistic regression model, statistically significant predictors were rated based on their odds ratios in order to build a personalized grading scale – the Peri-Operative Chordoma Scale (POCS). Results. Eighty-seven consecutive patients were surgically treated for a skull base chordoma during the period of recruitment. Seventy-eight patients were eligible for the retrospective review. There were 38 males (48.7%) and 40 females (51.3%). The mean follow-up was 69 months (range, 3–233). One-hundred-fourteen surgical operations were performed in the initial recruitment or recurrent setting. The presence of motor deficits in skull base chordoma revealed to be a significant prognostic factor correlating with a worse PFS (p=0.0480). Calcification on KM analysis showed a correlation with better outcomes (OS) compared with tumor lacking any calcification on CT scan (p value=0.0402). The degree of MR contrast enhancement revealed to be a significant and strong prognostic factor in terms of OS and PFS (p≤0.0001 and 0.0010, respectively). Jugular foramen involvement represented a significant prognostic factor with a worse PFS in the cohort of primary skull base chordomas (p=0.0130). The presence of chordoma in the pre-brainstem cistern revealed to be a significant prognostic factor with a worse PFS in the cohort of recurrent skull base chordomas (p=0.0210). Brainstem dislocation represented a significant prognostic factor correlating with a both worse outcome in terms of OS and PFS in the cohort of recurrent skull base chordomas (p=0.0060 and 0.0030). Extent of resection represents a strong prognostic factor according to PFS in the cohort of primary skull base chordomas (p=0.0200). Patients operated by an experienced chordoma surgeon did better in terms of prolonged PFS in the cohort of primary patients (p=0.0340). Development of post-operative complications in primary skull base chordoma patients represented an important prognostic factor related to both OS and PFS (p≤0.0001 and 0.0360, respectively). In the cohort of recurrent chordomas, ∆KPS correlated to both OS and PFS (p=0.0010 and 0.0180, respectively). Moreover, post-operative radiation treatment correlated with prolonged OS (p=0.0020) and PFS (p=0.0100). The following factors were found to be statistically significant predictors of both PFS and OS in the logistic regression model: MR contrast enhancement (intense vs mild/no), preoperative motor deficit (yes vs no) and the development of any post-operative complications (yes vs no). A grading scale was obtained with scores ranging between 0 and 17 (Nagelkerke’s pseudo R2=0.656). The mean total ceramides and dihydroceramides species in primary chordomas were 808.4±451.4 pmol/mg (522.5-1760.2) and 30.7±16.4 pmol/mg (17.6-62.4), respectively. The mean total ceramides and dihydroceramides species in recurrent chordomas were 1488.1±763.8 pmol/mg (540.7-2787.5) and 67.2±45.5 pmol/mg (9.0-145.6), respectively. Total ceramides species were significantly higher in recurrent chordomas that underwent previous surgical resection and radiation therapy in comparison to the primary chordomas (p=0.0496). The mean total ceramides and dihydroceramides species in “intense enhancement” group were 1597.6±737.8 pmol/mg (592.7-2787.5) and 69.1±45.0 pmol/mg (17.8-145.6), respectively. The mean total ceramides and dihydroceramides species in “no or mild enhancement” group were 664.7±120.4 pmol/mg (522.5-826.0) and 31.5±13.6 pmol/mg (17.6-53.6), respectively. Total ceramides and dihydroceramides were significantly higher in “intense enhancement” chordomas in comparison to the “no/mild enhancement” chordomas (p=0.0290 and p=0.0186, respectively). Analyzing the association between ceramides level and MIB-1 within each skull base chordoma patient, total ceramides level showed a strong association (r=0.7257, r2=0.5267) with MIB-1 staining (p=0.0033). Analyzing the association between DHCer level and MIB-1 within each skull base chordoma patient, total DHCer level showed also strong association (r=0.6733, r2= 0.4533) with MIB-1 staining (p= 0.0083). Among the single ceramides species Cer C24:1 (r=0.8814, r2=0.7769, p≤0.0001), DHCer C24:1 (r=0.8429, r2=0.7104, p=0.0002) and DHCer C18:0 (r=0.9426, r2=0.8885, p≤0.0001) levels showed a significant correlation with MIB-1 staining. Final candidate predictive factors that well fitted the regression model were: cer24:1 (r=0.824, p≤0.001), and DHCer C18:0 (r=0.748, p=0.002). Conclusion. Our clinical analysis showed that pre-operative clinical symptoms (motor and cranial nerve deficits), anatomical location (jugular foramen, pre-brainstem cisterns and brainstem dislocation), surgical features (extent of tumor resection and surgeon’s experience), development of post-operative complications and KPS decline represent significant prognostic factors. The degree of MR contrast enhancement significantly correlated to both OS and PFS. We also preliminarily developed the Peri-Operative Chordoma Scale (POCS) to aid the practitioner in the personalized management of patients undergoing potential adjuvant therapies. Our lipid analysis showed ceramides as promising tumoral bio-markers in skull base chordomas. Long and very long chain ceramides, such as Cer C24:1 and DHCer C24:1, may be related to a prolonged tumor survival, aggressiveness and the understanding of their effective biological role will hopefully shed lights on the mechanisms of chordoma radio-resistance, tendency to recur and use of agents targeting ceramide metabolism. Such results should be validated in future larger clinical, in-vitro and in-vivo studies to confirm such intricate link between ceramides and chordoma aggressive behavior.