Patent ID: 12201302

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings,FIG.1shows a first embodiment of a ligation device of the invention, generally referenced2, comprising a plastic inner tubular member4having a convergent tubular section6with an inner surface9and an integrally formed straight cylindrical section8. The convergent tubular section6has a rear end10and a front end12for retaining a stretched elastic band14over the front end12thereof.

In the embodiment illustrated inFIG.1, the inner tubular member4has a convergent tubular configuration extending continuously from the rear end10to the front end12and for a sufficient distance to facilitate insertion into the rectum of a patient.

A plunger16is slideably disposed in the cylindrical section8, and has a stem center section18, a head20at one end of a stem section18and a handle22at the other end of the stem section18and extending away from the front end12of the inner tubular member4. The head20is typically fabricated from rubber and is adapted for sealingly engaging with an inner wall of the cylindrical section8. In the embodiment shown inFIG.1, a sealing member23is mounted to be at a gap between opposing flanges25on the head20for sealingly engaging with the inner wall24of the cylindrical section8.

In the embodiment shown inFIG.1, the plunger16is integrally formed with an obturator26disposed internally of the inner tubular member. The obturator is provided with a rounded end portion28which by movement of the plunger may protrude beyond the end12of the inner tubular member, through opening13, as shown inFIG.1, or may be positioned within the interior of the inner tubular member, as shown inFIGS.8and9(discussed below). The purpose of the obturator is to facilitate access of the ligation device when inserted into the rectum of a patient.

The handle22permits the plunger16to be slid away from the front end12of the inner tubular member4to provide a suction for drawing hemorrhoidal tissue into the inner tubular member4through the opening13at the front end12. The opening13may be slightly smaller in diameter than the inner tubular member4. In another embodiment, the cylindrical section8and inner tubular member4may be separate components joined together.

A plastic outer tubular pusher sleeve30is provided and a straight cylindrical section32and a tapering tubular section34corresponding to the taper of the convergent section of the inner tubular member4. The outer tubular pusher sleeve30has a limited friction fit over the length of the inner tubular member4, and has an external end36adjacent the stretched elastic band14and an opposite end38provided with a locking mechanism40.

The locking mechanism shown inFIG.2Aand generally referenced40includes a tab42engageable with a locking ring44provided on the exterior surface of the inner tubular member4. The locking ring has an abutment surface48extending at 90 degrees to the outer surface of the inner tubular member. The tab42is provided with a lug46which protrudes at 90 degrees from the tab42and abuts against the abutment surface48, thereby preventing movement of the outer pusher sleeve towards the front end of the device. Upon pushing the tab42away from the inner tubular member4, the lug46moves out of abutting relationship with the abutment surface48which allows the outer pusher sleeve to be moved relative to the inner tubular member4towards the front end of the device, thereby to push an elastic band off the front end of the device onto hemorrhoidal tissue. The locking mechanism40ensures that unintentional deployment of the elastic band as a result of movement of the outer pusher sleeve towards the front end of the device does not occur until the outer pusher sleeve is unlocked by the user.

FIG.2Bshows in cross-section the distal end of the inner tubular member end4with the end28of the obturator partially protruding from the opening13. The outer surface11of the end28is convergent towards the distal tip of the obturator, creating an angle of 5-25 degrees between the outer surface11of the obturator end28and the inner surface9of the inner tubular member4. This feature serves to reduce pinching of tissue when the obturator26is moved relative to the inner tubular member, particularly when the obturator is withdrawn into the inner tubular member4. This anti-pinch feature allows gaps to increase as components move together, or allows for no gap as they move together, thereby minimizing the risk of pinching of tissue as the end of the obturator emerges from or is retracted into the inner tubular member4. In the illustrated arrangement, pinching is reduced as the pinch area increases allowing material to move away freely. As indicated inFIG.2B, the angle between the outer surface of the end28and the inner surface of the inner tubular member is typically in the range of 5-25 degrees, for example 5-10 degrees, and is typically about 30 degrees or less.

FIG.3Ashows the tab42and the lug46. Cut-outs47′ and47″ are provided to permit adjustment to tune the force required to deflect the tab42away from the inner tubular member. The highest force would be a configuration with no cut-out, decreasing in force as the cut-outs deepen and widen.

FIG.3Bis a side view of the outer pusher sleeve30andFIG.3Cis a top view of the outer pusher sleeve30.FIG.3Dis a cross-sectional view of the outer pusher sleeve30along the line3D-3D inFIG.3CandFIG.3Eis a view from the distal end of the outer pusher sleeve30.FIG.3Fis a view from the proximal end of the outer pusher sleeve30.

FIG.4shows the inner tubular member4with the locking ring44disposed on the outer circumference thereof. The shape of the locking ring is shown in greater detail inFIG.2A.

FIG.5Ashows a circumferential ring marker50provided on the external circumference of the outer tubular pusher sleeve30. This serves as a depth marker to the user with regard to the extent of insertion of the device into the rectum of the patient.FIG.5Aalso shows the obturator26protruding from the end of the inner tubular member.FIG.5Bis a view from the distal end of the device shown inFIG.5A.

FIGS.6A-6Cshow views of the elastic band introducer60.FIG.6Ais perspective view of the elastic band introducer60showing surface ribs61and channels63.FIG.6Bis a side view of the elastic band introducer ofFIG.6AandFIG.6Cis a cross-sectional view of the elastic band introducer along the line6C-6C inFIG.6B. The tapered surface65of the introducer60facilitates loading of elastic bands thereon by rolling the bands onto flat region67of the introducer prior to pushing the bands onto the inner tubular member4.

FIG.7shows a side view of the device showing the locking mechanism40and cut outs47′ and47″. In the embodiment shown, the locking mechanism40is engaged with the locking ring44on the inner tubular member4.

FIG.8is a cross-sectional view of the device showing the obturator26partially withdrawn inside the inner tubular member4, andFIG.9is a cross-sectional view of the device showing the obturator26fully withdrawn inside the inner tubular member4.FIG.10is a cross-sectional view of the device showing the obturator26protruding from the end of the inner tubular member4.

FIG.11is a cross-sectional view of the elastic band introducer60on the distal end of the inner tubular member4whereby the end of the inner tubular member4is received within slot69of the introducer60. In this way, elastic band(s)14loaded on the flat region67can be rolled onto the outer surface of the inner tubular member downstream of the distal end of the outer tubular pusher sleeve30.

FIG.12is a side view of a combined plunger16and obturator26for use in the device of the invention. As noted earlier, the plunger and obturator may be separate items or may be integrally formed in one piece, as shown inFIG.12. The rounded end section28facilitates more comfortable access of the ligation device into the rectum of a patient.

FIGS.13and14are side views of an alternative embodiment showing a differently shaped end for the obturator26. In this embodiment, the distal end of the obturator has a region of reduced diameter26′ towards the tip to further facilitate entry of the device into the rectum of the patient and to reduce the incidence of pinching of tissue as the obturator is withdrawn into the device after deployment of a band onto the hemorrhoidal tissue.

FIG.15is a. cross-sectional view along line15-15ofFIG.14.FIG.16is a cross-sectional view of the circled portion ofFIG.15showing in greater detail the region26′ of reduced diameter towards the obturator tip.

FIG.17is a cross-sectional view of the circled portion ofFIG.16showing an alternative embodiment whereby a flexible anti-pinch wiper element70suitably of a thin plastics material is connected to, or integrally formed with, the end of the inner tubular member4. The flexible anti-pinch element70is disposed such it abuts against the outer surface of the end of the obturator and prevents tissue from being trapped or pinched between the outer surface of the end of the obturator and the inner surface of the inner tubular member4.

FIGS.18and19are side views of another embodiment showing a differently shaped end for the obturator. In this embodiment, the end72has parallel walls74rounded at76at the tip of the obturator, which reduces the incidence of pinching of tissue.

FIG.20is a cross-sectional view along line20-20ofFIG.19.FIG.21is a cross-sectional view of the circled portion ofFIG.20showing in greater detail the region the configuration of the obturator tip72.

FIG.22is a cross-sectional view of the circled portion ofFIG.21showing a further alternative embodiment whereby a flexible anti-pinch wiper element80suitably of a thin plastics material is connected to, or integrally formed with, the end of the inner tubular member4. The flexible anti-pinch element80comprises a distal end, a proximal end, a wiper element inner surface and a wiper element outer surface, the wiper element outer surface being inclined, and the inner and outer wiper element surfaces converging from the proximal end to the distal end. The distal end abuts against the outer surface of the end of the obturator72and prevents tissue from being trapped or pinched between the outer surface of the end of the obturator72and the inner surface of the inner tubular member4.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.