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Microneuroendoscopy of spinal cord (MINOSC)

Leistungen

In this result clinical indications in relation with the different pathologies that can take benefit of a minimally invasive visual approach of spinal cord are defined. Four pathological circumstances have been identified: the traumatic lesions of the spinal cord, the malformations, the tumours of spinal cord and the arachnoïd reactions after surgery. In the first category (traumatic lesions of the spinal cord) the fluidic system of Minosc can be used for the injection of neurotransmitters like all the varieties of NGF(nerve growth factors) or inductors of new vessels to improve the trophicity of the nervous tissue as well as for the pumping of hematomas. In the second category (malformations), the important perturbation of the CSF circulation in the spina bifida pathology, requires drainage and dissection of cysts and cavities: Minosc indications can be found especially in case of recurrence of troubles and to treat cystic cavities. In the same category, treatment of arterio-venous malformations (AVM) can be also possible using very thin catheter to pump or to close a venous drainage inaccessible by the interventional way. Regarding tumors, the possibility to do a biopsy using Minosc procedure will be of great help avoiding surgical exploration only for biopsy. In case of Post surgical arachnoïd reactions, having the possibility to have a look at the local situation and to clean gently with a hydrodissection the fibrous adherences between roots until the level of the vertebral foramen could be of great help and solve the problem of reduced nerve motility. That is particularly true for the surgical approach done on the cauda equine where all the inferior roots are concentrated. Removing a cyst or a little radicular tumour can be also a possibility for Minosc as well as the liberation of an isolated sector of the meningeal space blocking the free circulation of CSF. It is important to have the possibility to suggest to patients having had many surgical operations without a full clinical success, to get a non-invasive neuromyeloscopy in order for the patient and the physician in charge to see images of the real local situation.
Study Design: Study of the morphology of the spinal dural sac and contents, using Magnetic Resonance Imaging. Objectives: To define the inner geometrical dimensions that confine the maneuver of an endoscope inserted in the lumbar region and along the thoracic and cervical spine. Summary of Background Data: The morphology of the spine has been studied since the development of myelography. However, most studies have measured the diameters of the spinal cord only, not the size of the subarachnoid space. In addition, the few studies available on the subarachnoid space have focused on the cervical spine, leaving a near-complete dearth of data on the subarachnoid space dimensions along the thoracic spine. Methods: Based on MRI images of the spine from 42 patients, the dimensions of the spinal cord, dural sac, and subarachnoid space were measured at mid-vertebral and inter-vertebral disc levels. Results: It was found that at each selected transverse level, the subarachnoid space tends to be symmetric on the right and left sides of the cord, and measures 2.5 mm on average. However, the posterior and anterior segments, measured on the mid-sagittal plane, are generally assymetric and vary widely in size, ranging from 1 to 5 mm. These measurements match those found in previous studies, where these are available. The coefficient of variance for the dimensions of the subarachnoid space is as high as 42.4%, while that for the dimensions of the spinal cord is 10%-15%. Conclusions: The findings presented here expand our knowledge of the spinal canal's morphology, and show that an endoscope designed to travel within the subarachnoid space must be smaller than 2.5 mm in diameter. Keywords: Subarachnoid space, Spinal Canal, Morphology, MRI, Endoscopy
This results is composed of two main modules: - a transparent simplified model similar to the subarachnoid space, based on geometrical anatomical characterization and made out of off-the-shelf components (polycarbonate shells, nylon wires, silicone tubes); - a real scale spine model based on volumetric images of a real human body, 3D printed and silicone moulded. Through this devices high-fidelity endoscopic simulations are possible. A physical, as opposed to a geometric, mathematical model of anatomical structures, can much more easily be tuned to achieve authentic response. It can interact naturally with endoluminal medical devices and tools and provide a natural response to events of many types (contact, navigation, ...). Because of their realistic representations of the body, physics-based surgical simulators can support the development of new techniques and procedures. The commercial potential of this result has a twofold value: artificial mock-ups of the subarachnoid space can become a new product to be included in the catalogues of companies selling products to medical doctors, or they can be used by companies developing active endoscopes and interested in an advanced in-vitro testing before animal experiments.
Experimental results on animals and cadavers done by using the Minosc system are especially important for the medical community and for the industry. In particular animal tests are of major importance under a physiological point of view (for proving the absence of damages and the benefits brought by the proposed medical technology), while cadaver tests are important to prove the effectiveness in human anatomy.