A rail-guided epidural-spinal needle, which includes an epidural needle including a base and a needle shaft connected to the base, the needle shaft having a groove that is formed on an outer surface of the needle shaft and extends along an axis of the needle shaft, the base having an elevated spinal needle inlet disposed thereon, the spinal needle inlet having a conduit formed therein, the conduit being of an acute angle with the groove in a side view of the epidural needle, and being in alignment with the groove in a top view of the epidural needle. The rail-guided epidural-spinal needle also includes a spinal needle having a tip with a unilaterally curved conformation down one side, such that, when the spinal needle is inserted into the conduit of the spinal needle inlet, and pushed forward, the tip thereof reaches the groove and slides along the groove.

BACKGROUND

1. Technical Field

The present invention relates to an epidural-spinal needle. More specifically, it relates to a rail-guided puncture needle for combined epidural-spinal anesthesia.

2. Background Information

Puncture anesthesia is used in a variety of medical and surgical procedures. In a typical puncture anesthesia process, an epidural needle is first punctured into an epidural space, a spinal needle, guided by an inner lumen of the epidural needle, is then inserted to pierce the spine dura mater and the arachnoids mater associated to the epidural space to arrive at the subarachnoid space. An anesthetic agent may then be administrated into subarachnoid space through the spinal needle. After the spinal needle is withdrawn, an epidural catheter can be threaded into epidural space through the inner lumen of the epidural needle, so that continuous epidural anesthesia can be applied via the epidural catheter. Finally, the epidural needle is removed to complete the anesthesia puncture process.

A conventional epidural needle has a lumen formed therein. The spinal needle is inserted into the lumen, and the tip of the spinal needle passes through the lumen to pierce the spine dura mater and the arachnoids mater into subarachnoid space. After the spinal needle is withdrawn from the lumen, the epidural catheter is disposed into epidural space through the same lumen.

SUMMARY

A rail-guided epidural-spinal needle, which includes an epidural needle including a base and a needle shaft connected to the base, the needle shaft having a groove that is formed on an outer surface of the needle shaft and extends along an axis of the needle shaft, the base having an elevated spinal needle inlet disposed thereon, the spinal needle inlet having a conduit formed therein, the conduit being of an acute angle with the groove in a side view of the epidural needle, and being in alignment with the groove in a top view of the epidural needle. The rail-guided epidural-spinal needle also includes a spinal needle having a tip with a unilaterally curved conformation down one side (that is, a beaked structure), such that, when the spinal needle is inserted into the spinal needle inlet and the conduit and pushed forward, the tip thereof reaches the groove and slides along the groove.

DETAILED DESCRIPTION

The invention will now be described in more detail by way of example with reference to the embodiments shown in the accompanying Figures. It should be kept in mind that the following described embodiments are only presented by way of example and should not be construed as limiting the inventive concept to any particular physical configuration. Further, if used and unless otherwise stated, the terms “upper,” “lower,” “front,” “back,” “over,” “under,” and similar such terms are not to be construed as limiting the invention to a particular orientation. Instead, these terms are used only on a relative basis.

The epidural needle in one embodiment of the invention is illustrated inFIG. 1.FIGS. 2A-2Crespectively show a top view, a bottom view and a side view of the epidural needle. As illustrated inFIG. 1, the epidural needle10includes a needle shaft11and a hub12. One end of the needle shaft11constitutes the tip13of the epidural needle10, and the other end of the needle shaft11is connected to the hub12. The tip13of the epidural needle10bends slightly downwards, as in a conventional epidural needle. Any type of epidural needle tips that may be contemplated by a person of ordinary skill in the art may be used here. A groove14is formed on the outer surface of the needle shaft11in parallel to the axis of the cylindrical portion of the needle shaft11. The groove14functions as a rail to guide the spinal needle20(shown inFIG. 3) when the spinal needle20is used with the epidural needle10, as described below.

The hub12of the epidural needle10includes a base15in connection with the needle shaft11, and an elevated spinal needle inlet16disposed on the base15. Although the surfaces of the base15in the embodiment illustrated inFIG. 1are smooth, the base15in alternative embodiments may have rugged surfaces or patterned surfaces to facilitate the handling of the epidural needle10. As illustrated inFIG. 2C, the spinal needle inlet16has a conduit18through which a spinal needle20(shown inFIG. 3) can be inserted (as shown inFIGS. 4A and 4B). The dashed line L represents the path of a point on the tip23(shown inFIG. 3) of the spinal needle20, when the spinal needle20is inserted through the conduit18. An acute angle α is formed between L and the groove14, as shown inFIG. 2C. As also illustrated inFIG. 2A, the path L, in a top view, is in alignment with the groove14. In one embodiment of the invention, the conduit18does not intersect with the groove14, so as to allow the movement of the tip23of the spinal needle20along the groove14when the spinal need20, moving through the conduit18, reaches the groove14.

The spinal needle in one embodiment of the invention is illustrated inFIG. 3. The spinal needle20includes a needle body21and a needle handle22. One end of the needle body21is connected to the needle handle22, and the other end of the needle body21constitutes the tip23of the spinal needle20. As illustrated inFIGS. 4A and 4B, the spinal needle20may be inserted into the groove14via the conduit18, and subsequently slides along the groove14. The tip23of the spinal needle20has a unilaterally curved conformation down one side (that is, a beaked structure), so that when the spinal needle20slides along the groove14, the foremost portion of the tip23of the spinal needle20remains in the groove14, so as to avoid the accidental derailment of the spinal needle20from the groove14. The surfaces of the needle handle22in the embodiment illustrated inFIG. 3are smooth, but in alternative embodiments they may be rugged or patterned to facilitate the handling of the spinal needle20.

The epidural needle10has a lumen17(seeFIG. 5) formed therein along the axis of the needle shaft11. The lumen17is separated from the groove14and is not in communication with the groove14, as a sectional view shows inFIG. 5. The lumen17has a relatively large gauge to permit better assessment of loss of resistance and the passage of an epidural catheter and liquid medicine. The bottom view of the epidural needle10, illustrated inFIG. 2B, shows an orifice17A of the lumen17. The spinal needle20also has a lumen (not shown) formed therein to allow the administration of the anesthetic agent.

FIGS. 4A and 4Billustrate steps of a typical puncture anesthesia process using the epidural-spinal needle in one embodiment of the invention. The epidural needle10is first punctured into the epidural space, and an epidural catheter (not shown) is placed into the epidural space through the lumen17of the epidural needle10. Next, the spinal needle20is inserted into the conduit18of the spinal needle inlet16, as shown inFIG. 4A. The spinal needle20is pushed forward until its tip23reaches the groove14of the epidural needle10. The spinal needle20is then pushed forward further so as to slide along the groove14, as shown inFIG. 4B. Since an acute angle a is formed between L and the groove14, so that when the spinal needle20is pushed forward, it is also pressed downward towards the bottom of the groove14, and also because the tip23of the spinal needle20has a unilaterally curved conformation down one side (that is, a beaked structure), so that the foremost portion of the tip23of the spinal needle20remains in the groove14when sliding forward, the spinal needle20slides along the groove14until it arrives at the epidural space. Then the tip of the spinal needle20pierces the spine dura mater and the arachnoids mater into the subarachnoid space, and anesthetic agent is injected through the spinal needle20into the subarachnoid space. Afterwards, the spinal needle20and the epidural needle10are in turn withdrawn.

By using the epidural-spinal needle of the invention, firstly, the epidural catheter can be disposed in place through the lumen of the epidural needle, and then the spinal needle is guided by the groove into the subarachnoid space, so as to avoid the problem of conventional techniques, in which spinal needle is inserted into the subarachnoid space to administer the anesthetic agent through the inner lumen of epidural needle firstly, and then epidural catheter is placed in the epidural space through the inner lumen of epidural needle after the spinal needle being withdrawn. As such, it also prevents the epidural catheter from being inserted into the subarachnoid space through the needle hole of the spinal needle.

It should be understood, that the invention is not necessarily limited to the specific process, arrangement, materials and components shown and described above, but may be susceptible to numerous variations within the scope of the invention.