Patent Application
20210369094
The present invention relates generally to devices and methods for endoscopic intrauterine fallopian tube access and navigation. More specifically, it relates to an oscillating transparent tapered-tipped endoscopic device employing force limitation that may be advanced to navigate the length of the fallopian tube.
An endoscopic guided catheter is desired that may navigate through the fallopian tube without incurring trauma or perforation, for purposes of tubal recanalization for infertility, or for tubal cell sampling in the diagnosis of ovarian cancer. The fallopian tube is delicate and tortuous, and conventional methods of cannulation using guidewire and tapered catheter advancement may cause injury or perforation. Catheter advancement through the length of the fallopian tube is presently performed under fluoroscopic guidance, generally following contrast dye injection via a hysterosalpingogram (HSG). If the HSG demonstrates tubal occlusion, guidewire and catheter passage may be performed to attempt to recanalize the occlusion. The occurrence of tubal perforation during catheter recanalization of the fallopian tube has been previously estimated at 4% of procedures.
A linear everting balloon has also been used to deliver an endoscope called a falloposcope into the fallopian tube. The balloon is initially inverted into the lumen of the outer catheter, and the falloposcope resides inside the inverted balloon and inner catheter. The outer catheter is pressurized to 10 atm of pressure, and advancement of the inner catheter everts the balloon and the falloposcope forward in the fallopian tube. The falloposcope moves forward at twice the rate of the everting balloon, necessitating incremental falloposcope retraction during balloon eversion, to prevent the falloposcope tip from perforating the fallopian tube. In a published study on the use of linear everting balloon falloposcopy in 304 patients, tubal perforation was reported in 1.3% of patients.
Cannulation of the fallopian tube has also been performed using a linear everting balloon catheter inserted through the working channel of a 5.5 Fr rigid hysteroscope. The hysteroscope is advanced into the uterus and manipulated to visualize the os of the fallopian tube and to guide insertion of the linear everting balloon catheter into the tube. Introduction of a rigid hysteroscope into the uterus requires manipulation of the cervix with sharp pointed tenaculum forceps, causing severe pain to the patient. This painful procedure is generally difficult or impossible to perform as an in-office procedure. It is desirable to develop a technique and device that may allow fallopian tube passage to be performed in the physician's office on an annual screening basis, without the requirement for anesthesia to control pain during the procedure. Annual cell sampling from the fallopian tube is desired for screening to detect the occurrence of ovarian cancer, which has been demonstrated to derive from the fallopian tube. Ovarian cancer occurs with a ten-fold greater incidence in patients who carry the BRCA gene mutation. In the United States, there are 313,000 women between the ages of 15 to 80 who carry the BRCA gene mutation and require annual screening for the development of ovarian cancer. In addition, 250,000 women a year are diagnosed with an ovarian cyst, and at present, there is no non-surgical modality for determining whether an ovarian mass is a benign cyst or a malignant tumor. An atraumatic in-office device for fallopian tube cell sampling is desired, akin to the traditional Papinicoloau test, or Pap smear, for cervical cancer. In a Pap smear, a vaginal speculum is inserted to allow the introduction of a cotton-tipped applicator to the surface of the cervix for cytological cell collection. Use of a tenaculum forceps is unnecessary, and the procedure is performed as a standard annual in-office examination.
The present invention comprises a substantially rigid cannula, typically having a slight angulation in its distal portion configured to be inserted into a patient's uterus and rotated to align the angled tip with the os of the fallopian tube. A transparent tapered-tipped catheter having a viewing element, such as a CMOS-chip endoscope, is configured to be distally advanced through an inner lumen of the cannula with the viewing element at a shoulder of the transparent tapered tip. A cell or tissue sampling element may be positioned immediately proximal to the transparent tapered tip, such as a gauze cuff disposed coaxially over an external surface of the catheter.
In an exemplary embodiment of the present invention, the gauze cuff may used to collect cells from an inner surface of the fallopian tube. A shoulder of the gauze cuff initially lies flush with the distal end of the cannula as the cannula is advanced under endoscopic guidance through the patient's cervical os and into the uterus. Most of the length of the transparent tapered tip lies distal to the distal end of the CMOS-chip endoscope, e.g. to provide a 5-7 mm long field of view ahead of the endoscope. Rotation of the cannula is performed to align the tapered-tipped endoscope with either the left or the right os of the fallopian tube. The endoscopic tapered-tipped catheter may be advanced into the fallopian tube while the distal end of the cannula remains outside the os of the fallopian tube. The tapered-tipped catheter is typically configured to rotationally oscillate (provided with a reciprocal rotational capability), rotating alternately clockwise and counter-clockwise in an arc of 20° to 120°, typically 60°, in either direction from an initial vertical position, while the cannula and the CMOS-chip endoscope inside the catheter remain stationary. The tapered-tipped catheter is advanced forward through a length of the fallopian tube lumen while reciprocal rotation is conducted. The reciprocal rotation allows the tapered-tipped catheter to be advanced through a delicate tubal structure that is characteristically tortuous, collapsed, and may be stenotic or occluded. The transparent tapered tip gently dissects through collapsed or occluded tubal segments with its reciprocal rotational movements, avoiding the perforation experienced with advancement of a guidewire and 3 Fr catheter in a similar setting. A reciprocal rotation of the catheter is used instead of a unidirectional rotation, to avoid twisting and winding of the tube in the event of friction and adhesion of the tapered-tipped catheter to the inner surface of the fallopian tube. Due to the delicate nature of the fallopian tube, traction and twisting may result in tubal perforation or transection.
The cannula may be constructed of a polymeric material such as polyurethane, nylon, or polyethylene, or it may be constructed of stainless steel with an outer coating of polymer to provide atraumatic passage through the cervix into the uterus The outer diameter of the cannula is typically 3-5 mm, usually being approximately 4 mm, with a working length of 20-30 cm, usually approximately 25 cm, and the distal 1 cm of its tip may incorporate approximately a 20° bend angle. The transparent tapered conical tip may have a maximal outer diameter of approximately 1-1.3 mm, a rounded distal tip of 0.2-0.3 mm radius, and a length of approximately 7-10 mm.
The transparent tapered tip may be rigid, semi-rigid, flexible, or elastic, or combinations thereof. In certain instances, the transparent tapered tip will have a rigid or semi-rigid structure, typically being constructed of a transparent, inelastic polymer such as polycarbonate, polyethylene terephthalate (PET), polyvinyl chloride, polyurethane, nylon or similar material. Such rigid or semi-rigid structure may be sealed and filled with a transparent gas or liquid to permit viewing, Alternatively, the tip may be formed of an elastic material, such as silicone rubber, polyisoprene, or polyurethane, and it may be inflatable with a transparent gas or liquid to form an expanded balloon.
The catheter body may be constructed of a flexible polymer such as polyurethane, polyvinyl chloride, PET, nylon or similar material, or it may be formed of a composite structure to impart reinforcement against bending or kinking. The catheter shaft may incorporate metallic spiral reinforcement, or a braid of polymer or metallic fibers to transmit torque along its length, and to allow for rotational oscillation (reciprocal rotation) as it navigates through the tortuous fallopian tube. The working length of the catheter will be approximately 35-40 cm, to allow the transparent tapered tip to travel the typical 10 cm length of the fallopian tube distal to the end of the cannula. A proximal portion of the catheter referred to elsewhere herein as an extension, may have a length of approximately 15-30 cm and may be bonded to an outer section of stainless steel tube, rendering the entire proximal portion rigid. Providing a rigid proximal extension and limiting the flexible length of the tapered-tip catheter to approximately 10 cm provides a catheter structure with sufficient column strength and torque control to advance and rotationally oscillate the catheter through the fallopian tube lumen, as described in detail elsewhere herein. The rigid proximal portion also provides structure for transmitting forces to the catheter for both axial advancement and rotational oscillation, as described in detail elsewhere herein.
In an exemplary embodiment, a circumferential fabric gauze cuff, typically having a length in a range from 0.5-1.5 cm, is attached to a distal end of the viewing catheter, typically being located immediately proximal to the transparent tapered tip. The gauze cuff serves as a mechanism for cell collection, as the endoscopic catheter advances the length of the fallopian tube. The interstices of the gauze cuff retain endothelial fallopian tube cells. Cell collection is assisted by reciprocal rotation of the cuff during catheter advancement and withdrawal. The gauze cuff may be constructed of a material such as silk, cotton or polyester, with a thickness of approximately 0.5 mm. Following advancement of the catheter the length of the fallopian tube, the falloposcope device is removed from the patient, and the distal tip of the catheter containing the gauze cuff is detached or severed and submitted for cell analysis.
In an exemplary embodiment, a handle on a proximal end of the cannula incorporates a mechanism for axially advancing and simultaneously rotationally oscillating the transparent tapered tip catheter while maintaining a stationary CMOS-chip endoscope. The handle may contain a trigger that is squeezed to drive a ratchet mechanism that advances an elongated toothed plate in a forward direction. A locking mechanism is provided to prevent the elongated toothed plate from moving in a backward direction. This locking mechanism may consist of a spring loaded tooth that engages the elongated toothed plate, with the tooth angled in a position to allow the plate to advance in a forward motion only. The lock may contain an actuator to allow it to release from engagement with the elongated toothed plate, to allow insertion or retraction of the toothed plate. Reciprocal bidirectional rotation of the catheter is performed during its advancement. The catheter is attached to a rigid tube that is activated by an actuation mechanism in the handle. The surface of the rigid tube may contain axially oriented splines or a frictional outer surface; for example, a textured or an outer coating of elastomer such as silicone rubber. The rigid tube may be attached to the elongated toothed plate in a fashion that allows the tube to rotate radially with respect to the plate. For example, open end caps on the elongated toothed plate may constrain the proximal and distal ends of the rigid tube while permitting it to rotate. A stepper motor attached to the handle may rotate a wheel or a gear that contacts the splined rigid tube. The surface of the wheel that contacts the rigid tube may contain a textured surface or an elastic coating to increase contact friction. As the handle trigger is depressed, the toothed plate and attached splined tube are advanced forward, while the splined tube rotates bi-directionally as driven by the stepper motor. Alternative means of accomplishing tube rotation may be used. For example, reciprocal rotation may be accomplished by using two electromagnets coupled to the shaft of the catheter that are activated in turn to cyclically angle the catheter in the left and right directions towards ferromagnetic strips residing on the inside of each handle half. A third mechanism for achieving bi-directional catheter rotation is the use of a rigid tube containing a sinusoidal shaped slot in its bottom aspect rotatably attached to a toothed plate containing a straight slot in its central portion, and a pin fixed to the handle that protrudes through the slot in the toothed plate and the sinusoidal slot in the rigid tube. Advancement of the toothed plate with its attached rigid tube with respect to the fixed pin causes the rigid tube to oscillate in a cyclical clockwise and counterclockwise rotational fashion as the sinusoidal groove rides along the rigid pin.
Force limitation is provided to limit the force exerted at the distal tip of the catheter. During advancement of the balloon catheter through the fallopian tube, if the transparent tapered tip exceeds a preset amount of contact force against the inner wall of the tube, the force limiter will prevent additional catheter advancement. This will prevent potential tubal perforation. Force limitation of catheter advancement may be performed via magnetic coupling of the ratchet drive mechanism. The handle trigger may contain a magnet that couples with a second magnet or a ferromagnetic disc attached to the toothed drive unit that interfaces with the elongated toothed plate. As the trigger is depressed to drive the catheter forward, excessive force exerted by the transparent tapered tip against fallopian tube tissue causes the magnetic interface to decouple and release. The strength of the magnetic coupling may be adjusted to yield the degree of force limitation desired. Catheter force limitation may alternatively be provided by addition of a compression spring to the trigger drive mechanism in the falloposcope device handle. At the upper limit of desired catheter tip force, the trigger compresses the spring rather than driving the toothed plate forward.
The handle houses the electronic components used to process a video signal generated by an electronic imaging element, such as a CMOS chip, position inside of or adjacent to the conical catheter tip. The imaging element is provided as part of a separate “micro-endoscope” which incorporates the CMOS or other electronic imaging element. Power is supplied to the CMOS chip or electronic imaging element by a conductive cable that extends the length of the catheter proximally to the control circuit board in the falloposcope device handle. The video signal obtained by the imaging element is transmitted via a second cable that lies coaxially to the power cable the length of the catheter. The coaxial power and signal transmission cables may be tightly bound by an outer sheath of a polymeric material such as polyethylene terephthalate (PET) heat shrink tubing, or a spiral wound coil of flat stainless steel or other metallic foil plus an outer sheath of PET heat shrink. The coaxial conductive cables plus the spiral wound coil and outer sheath have a combined outer diameter that is smaller than the inner diameter of the catheter, allowing the CMOS chip to remain stationary as the transparent tapered tip and catheter are reciprocally rotated. In addition, torsional stability is conferred to the coaxial conductive cables by the spiral wound coil and outer sheath, to prevent CMOS chip rotation, providing a stable video image. In other instances, instead of a CMOS video chip, the imaging element may be an optical fiber with a distal lens oriented to view within the transparent tapered tip which transmits the optical image to an imaging circuitry within the handle.
A video monitor is integrated into the handle, and this monitor may pivot in the axial direction to allow the physician to concurrently view the video image as well as patient anatomy.
Application of the oscillating endoscopic catheter to cannulation of the fallopian tube has been described in detail. The principle of employing bi-directional reciprocal rotation of a transparent tapered tip endoscopic catheter with advancement force limitation may also applied to other anatomic structures involving delicate tubular ducts or vessels within the body. For example, the oscillating endoscopic catheter may be advanced through the operating channel of a cystoscope, rather than the angled 4 mm diameter cannula, and the oscillating transparent tapered tip catheter advanced in a retrograde fashion through the length of the ureter, to dislodge impacted renal stones, or to dilate ureteral strictures. Another version of the device may be advanced through the operating channel of a duodenoscope and used to cannulate the pancreatic duct or the cystic duct, to dilate strictures in the ducts or to dislodge impacted gallstones. Other versions of the oscillating transparent tapered tip endoscopic catheter may be applied to blood vessels such as arteries or veins, to recanalize occlusions due to thrombus or atherosclerotic disease. Occlusions in arteriovenous grafts used for vascular access in renal dialysis may similarly be addressed. Recanalization of occluded tubular device implants may also be performed using the oscillating endoscopic catheter. Ventriculoperitoneal shunts are placed in the treatment of hydrocephalus, and these shunts often occlude over time. An oscillating transparent tapered tip endoscopic catheter may be inserted laparoscopically to cannulate the length of a ventriculoperitoneal shunt and clear occlusions within the shunt.
The oscillating endoscopic catheter may serve as an access device to deliver an intraluminal stent or an intraluminal implant. The gauze cuff of the described device may be replaced with a self-expanding vascular stent that is deployed following recanalization of an arterial or venous occlusion using the transparent tapered tip catheter of the falloposcope or other endoscopic catheter assembly of the present invention. The oscillating endoscopic catheter may be used to perform sinoscopy, traversing strictures in the nasal sinuses, and delivering bio-absorbable stents to correct occlusive strictures. Ureteral stents may also be placed via the device.
In a first aspect, the present invention provides a falloposcope intended for use with a hysteroscope or other uterine endoscopic access device. The falloposcope comprises a cannula having an angled tip oriented to engage a fallopian tube os when the cannula is transcervically introduced to a patient's uterus, typically through the hysteroscope. The catheter has a distal viewing tip configured to be advanced from a distal end of the cannula into the patient's uterus through a cervical os. A viewing chamber has a wide proximal end attached to the distal viewing tip of the catheter, and the viewing chamber is at least partially transparent and typically tapers in a distal direction to provide a clear viewing zone for the endoscope as well as atraumatic advancement into the fallopian tube.
In particular embodiments, the viewing chamber may be fully transparent, may be comprise a pre-shaped inflatable or other shell, and/or may comprise a pre-shaped conical shell with a narrow tip configured to allow atraumatic advancement through a lumen of the fallopian tube while also providing clear view of the luminal wall as it is separated by the conical surface. In a specific instance, the catheter may have a diameter in a range from 0.75 mm to 1 mm, the base of the pre-shaped shell has a diameter in a range from 1 mm to 1.25 mm, and the pre-shaped shell has a length in a range from 4 mm to 7.5 mm.
In addition to providing viewing of the interior of the fallopian tube lumen, the falloposcopes of the present invention may further comprise for cell collection, tissue sampling, biopsy, or other diagnostic procedures. For example, a fabric (gauze) cuff, brush, or other cell collection element located on an exterior of the catheter, typically being immediately proximal of the viewing chamber.
The falloposcopes of the present invention will typically include a handle attached to a proximal end of the cannula where the handle is configured to distally advance the catheter from the distal end of the cannula. The handle typically comprises a drive assembly configured to simultaneously advance and rotationally oscillate the catheter. For example, the drive assembly may comprise a trigger coupled to a ratchet mechanism which incrementally advances the catheter. The drive assembly typically further comprises a mechanism for rotationally oscillating the catheter. In one instance, the mechanism comprises a motor-driven rocker arm that engages and rotationally oscillates the catheter or an extension of the catheter. Alternatively, the mechanism comprises a pin fixed in the handle, wherein the pin tracks in a sinusoidal, zig-zag, or other serpentine groove formed in an exterior surface of the catheter or an extension of the catheter to cause the catheter to rotationally oscillate as the catheter is advanced by the trigger and ratchet. Further alternatively, the catheter may be caused to rotationally oscillate by coupling a pair of laterally adjacent electromagnets to the catheter or an extension thereof. By providing ferromagnetic strips on opposed sides of the handle, and alternately energizing the two magnets, the catheter can be alternately rotated in opposite rotational directions.
In a second aspect, the present invention provides a method for accessing a patient's fallopian tube. The method comprises transcervically introducing a distal end of a cannula into the patient's uterus to engage the patient's fallopian tube os. A catheter having a distal viewing tip is advanced from a distal end of the cannula into the patient's fallopian tube through the patient's fallopian tube os. The catheter is then atraumatically advanced through the patient's fallopian tube while viewing an interior of the fallopian tube through a tapered viewing chamber attached to the distal viewing tip of the catheter.
In particular instances of the methods of the present invention, the viewing chamber has a wide proximal end attached to the distal viewing tip of the catheter and the viewing chamber is at least partially transparent and tapers in a distal direction to provide both a clear viewing zone for the endoscope and atraumatic advancement into the fallopian tube. The viewing chamber is typically fully transparent and may comprise a pre-shaped shell which may further be conical in shape. In specific instances, the catheter may have a diameter in a range from 0.75 mm to 1 mm, the base of the pre-shaped shell has a base diameter in a range from 1 mm to 1.25 mm and a length in a range from 4 mm to 7.5 mm when inflated.
The methods will often further comprises diagnostic testing, such as cell collection, tissue collection biopsy, and the like. In particular the catheter may be used to collect and withdraw cells from the fallopian tube, for example by engaging a cell collecting surface on an exterior surface of the catheter against an inner wall of the fallopian tube. In specific instances, engaging a cell collecting surface comprises rotationally oscillating the catheter, typically while incrementally advancing the catheter using translating a ratchet mechanism.
While the present invention has been described herein with respect to certain illustrated embodiments, those of ordinary skill in the art will recognize and appreciate that it is not so limited. Rather, many additions, deletions, and modifications to the illustrated embodiments may be made without departing from the scope of the invention as claimed, including legal equivalents thereof. In addition, features from one embodiment may be combined with features of another embodiment while still being encompassed within the scope of the invention as contemplated by the inventors. Further, embodiments of the disclosure have utility with different and various tool types and configurations.
