The inventions described below relate to the field of minimally invasive surgery.
In our previous U.S. patent application, we disclose a cannula and camera system with an obturator comprising a small diameter shaft and larger diameter, transparent obturator tip that obturates the cannula at its distal end. Using the system, a surgeon can advance the cannula into the brain while viewing tissue distal to the obturator tip, through the obturator tip. The obturator tip may reverse the image of the tissue distal to the obturator tip, presenting at its proximal surface an image of tissue distal to the tip (at its distal surface) which is reversed, depending on its construction.
The devices and methods described below provide for improved visualization of the brain during minimally invasive surgery. The device comprises a cannula system with a camera mounted on the proximal end of the cannula with a view into the cannula lumen and the tissue within and below the lumen, and a obturator comprising a narrow shaft and a larger distal tip, which is transmissive to visible light (transparent or translucent), so that the tissue distal to the tip is at least partially visible, through the tip, from the proximal end of the cannula. The obturator tip preferably has a pointed, acutely conical distal tip, and includes an optically opaque component, such as a rod, disposed along the central axis of the obturator tip, which serves to prevent image reversal.
The small cross-section obturator shaft is much smaller than the inner diameter of the cannula, affording a sizable annular or circular space between the shaft and the cannula wall to provide good visibility (from the camera) of the proximal surface of the obturator tip. Lights, if necessary, may be provided in the cannula to illuminate the distal end of the obturator tip and cannula or tissue near the distal end of the cannula (lighting may instead be provided from a source outside the assembly, or from lights mounted on the proximal end of the cannula or any combination of the foregoing). Light reflected by tissue near the distal surface of the obturator tip passes through the obturator and out of the proximal surface of the obturator tip, so that a surgeon inserting or manipulating the assembly can easily see that the obturator tip is near brain tissue (which is white to gray) or blood (which is red to black).
The obturator tip is optically transmissive, not optically opaque, and may be optically transparent or optically translucent. The transmittance of the tip need only be adequate, in the visible spectrum, to pass the color of tissue in contact with the distal surface, given the brightness of any illumination provided by the light sources, to provide enough transmitted light to the camera and/or eye of the surgeon to allow the color of tissue around the distal tip to be discerned from light transmitted through the proximal surface of the tip. The obturator tip has a transverse cross-section closely matching a transverse cross-section of the cannula, and is slidable within the cannula tube, and positionable within the cannula tube such that the proximal end of the obturator shaft extends proximally out of the cannula proximal end while the tapered distal tip extends out of the cannula distal end. The obturator shaft has a transverse cross-section smaller than the lumen of the cannula and smaller that the transverse cross-section of the obturator tip, so that the proximal surface of the obturator tip is visible from the proximal end of the cannula, through the lumen, when the obturator tip is disposed within the cannula such that the tapered distal tip extends out of the cannula distal end.
The tip may be made of glass, silica, acrylic, polycarbonate, silicone, nylon, polyamides or copolymers or any other material suitable for use in a medical device. The obturator tip surface may be polished or frosted. The obturator tip may optionally comprise radiopaque substances (elements or compounds such as platinum particles, for example) to render the tip radiopaque, so that it appears distinctly under fluoroscopy during surgery. The obturator tip may optionally comprise sensors such as pH sensors, impedance sensors, force sensors, glucose sensors, etc., to assist in detecting a blood mass or CSF and distinguishing them from surrounding brain tissue.
The proximal surface of the tip, which tapers to a small diameter in the proximal direction, also provides for clearance of the tip when the obturator must be removed to make room for other devices, despite the position of the camera assembly at the distal end of the cannula tube.
As shown in
In embodiments in which the shaft bore terminates in the proximal conical section, or central cylindrical section, the neuro-navigation stylet distal tip 16d may extend distally beyond the shaft bore 14 (the larger bore which accommodated the shaft 11), and extend into the distal conical section (in the smaller bore 14d extending beyond the shaft bore, of smaller diameter that the shaft bore), for example into a smaller diameter bore the extends distally from the shaft bore, to serve as the opaque component. This is shown in
The shaft 11 may be a solid rod or a tube, with a small diameter, or transverse cross-section, compared to the cannula lumen and the obturator tip, so that the tip proximal surface can be viewed from the cannula proximal end. If provided as a tube, the lumen of the shaft may accommodate a neuro-navigation stylet or probe 15 with markers detectable by the neuro-navigation system, useful for guidance of the assembly into the brain. The rod 16 of the neuro-navigation stylet may be inserted into the lumen of tubular shaft, as shown, so that the assembled cannula, obturator and stylet may be tracked by a neuro-navigation system, through tracking of the markers 17 on a frame 18 to aid in accurate placement of the distal tip of the assembly. The shaft 11 may also accommodate a neuro starburst connection. In embodiments which include a neuro-navigation stylet, the distal tip of the stylet can terminate at any point within the obturator shaft, and may terminate proximal to the obturator tip, or within the obturator tip at a point proximal to the distal edge of the cannula or distal to the distal edge of the cannula.
In use, a surgeon will assemble the cannula tube, obturator, and, optionally, the neuro-navigation stylet for insertion into the body of a patient to gain access to a surgical workspace. For example, the method may entail providing a cannula system comprising the cannula tube, the obturator and the neuro-navigation stylet and assembling the cannula tube, obturator and neuro-navigation stylet such that the obturator is disposed within the cannula tube with the obturator tip extending distally from the cannula distal end and the distal end of end the neuro-navigation stylet extends distally from the obturator shaft and into the distal tip of the obturator tip to provide the opaque component within the distal tip, and advancing the assembled cannula system into the body while observing body tissue distal to the cannula tube, through the obturator tip, from the proximal end of the cannula tube. Where a neuro-navigation stylet is not to be used as the opaque component, the method may entail providing a cannula system comprising the cannula tube and the obturator, where the obturator tip further includes an opaque component disposed in the distal tip, and assembling the cannula tube and obturator such that the obturator is disposed within the cannula tube with the obturator tip extending distally from the cannula distal end such that the opaque component within the distal tip is disposed distally of the distal end of the cannula tube, and advancing the assembled cannula system into the body while observing body tissue distal to the cannula tube, through the obturator tip, from the proximal end of the cannula tube.
To aid in visualization, lights may be incorporated into the obturator tip to cast light on tissue distal to the tip and make it easier to see the tissue through the obturator tip from the proximal end of the cannula tube. As shown in
While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. The elements of the various embodiments may be incorporated into each of the other species to obtain the benefits of those elements in combination with such other species, and the various beneficial features may be employed in embodiments alone or in combination with each other. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.
This application claims priority to U.S. Provisional Application 62/809,445, filed Feb. 22, 2019, which is pending.
Number | Date | Country | |
---|---|---|---|
62809445 | Feb 2019 | US |