Securing Hemostasis in Pediatric Low-Grade Posterior Cerebral Fossa Tumors: The Value of Thrombin-Gelatin Hemostatic Matrix

Adeno-associated virus vector hydrogel formulations for brain cancer gene therapy applications

Gelatin-based formulations are utilized in neurosurgical procedures, with Medisponge® serving as an illustration of a secure and biocompatible hemostatic formulation. Noteworthy are combined hemostatic products that integrate pharmacological agents with gelatin. Gelatin matrices, which host biologically active substances, provide a platform for a variety of molecules. Biopolymers function as carriers for chemicals and genes, a facet particularly pertinent in brain cancer therapy, as gene therapy complement conventional approaches. The registration of Zolgensma underscores the efficacy of rAAV vectors in therapeutic gene delivery to the CNS. rAAVs, renowned for their safety, stability, and neuron-targeting capabilities, predominate in CNS gene therapy studies. The effectiveness of rAAV vector therapy varies based on the serotype and administration route. Local gene therapy employing hydrogel (e.g., post-tumor resection) enables the circumvention of the blood-brain barrier and restricts formulation diffusion. This study formulates gelatin rAAV gene formulations and evaluates vector transduction potential. Transduction efficiency was assessed using ex vivo mouse brains and in vitro cancer cell lines. In vitro, the transduction of rAAV vectors in gelatin matrices was quantified through qPCR, measuring the itr and Gfp expression. rAAVDJ and rAAV2 demonstrated superior transduction in ex vivo and in vitro models. Among the cell lines tested (Hs683, B16-F10, NIH:OVCAR-3), gelatin matrix F1 exhibited selective transduction, particularly with Hs683 human glioma cells, surpassing the performance Medisponge®. This research highlights the exploration of local brain cancer therapy, emphasizing the potential of gelatin as an rAAV vector carrier for gene therapy. The functional transduction activity of gelatin rAAV formulations is demonstrated.

Methods of Hemostasis in Cranial Neurosurgery: An Anatomy-Based Stepwise Review

BACKGROUND

Hemostasis is crucial in preventing hemorrhage during cranial neurosurgical procedures and maintaining visualization of the surgical field. There is significant variation in the availability of hemostatic methods across different settings and hemostatic techniques are being continuously developed over the decades of practicing neurosurgery. The aim of this article is to provide an outline of the potential methods to achieve hemostasis based on the sequential operative anatomy of a cranial operation.

METHODS

A systematic review was conducted following the PRISMA guidelines. The PubMed database was searched from inception of the database to July 18, 2023. A total of 64 studies were identified fulfilling predefined inclusion criteria, and the risk of bias was assessed using the Joanna Briggs Institute checklists.

RESULTS

Seventy-one hemostatic agents, techniques, tools, and devices were identified, which were then categorized according to the operative phase for which they are indicated. Nine operative anatomic targets were addressed in the sequence in which they are involved during a cranial procedure. For each anatomic target, the following number of hemostatic techniques/agents were identified: 11 for scalp, 3 for periosteum, 10 for skull bone, 11 for dura mater, 9 for venous sinuses, 5 for arteries, 6 for veins, 12 for brain parenchyma, and 4 for cerebral ventricles.

CONCLUSIONS

Depending on the phase of the surgery and the anatomic structure involved, the selection of the appropriate hemostatic method is determined by the source of bleeding. Surgeon awareness of all the potential techniques that can be applied to achieve hemostasis is paramount, especially when faced with operative nuances and difficult-to-control bleeding during cranial neurosurgical procedures.

Surgery of the lateral skull base: a 50-year endeavour

Disregarding the widely used division of skull base into anterior and lateral, since the skull base should be conceived as a single anatomic structure, it was to our convenience to group all those approaches that run from the antero-lateral, pure lateral and postero-lateral side of the skull base as “Surgery of the lateral skull base”. “50 years of endeavour” points to the great effort which has been made over the last decades, when more and more difficult surgeries were performed by reducing morbidity. The principle of lateral skull base surgery, “remove skull base bone to approach the base itself and the adjacent sites of the endo-esocranium”, was then combined with function preservation and with tailoring surgery to the pathology. The concept that histology dictates the extent of resection, balancing the intrinsic morbidity of each approach was the object of the first section of the present report. The main surgical approaches were described in the second section and were conceived not as a step-by-step description of technique, but as the highlighthening of the surgical principles. The third section was centered on open issues related to the tumor and its treatment. The topic of vestibular schwannoma was investigated with the current debate on observation, hearing preservation surgery, hearing rehabilitation, radiotherapy and the recent efforts to detect biological markers able to predict tumor growth. Jugular foramen paragangliomas were treated in the frame of radical or partial surgery, radiotherapy, partial “tailored” surgery and observation. Surgery on meningioma was debated from the point of view of the neurosurgeon and of the otologist. Endolymphatic sac tumors and malignant tumors of the external auditory canal were also treated, as well as chordomas, chondrosarcomas and petrous bone cholesteatomas. Finally, the fourth section focused on free-choice topics which were assigned to aknowledged experts. The aim of this work was attempting to report the state of the art of the lateral skull base surgery after 50 years of hard work and, above all, to raise questions on those issues which still need an answer, as to allow progress in knowledge through sharing of various experiences. At the end of the reading, if more doubts remain rather than certainties, the aim of this work will probably be achieved.