Patent GB-1123632-A (GB)
Title: Refrigerated surgical probe
Inventor: LAMB BERNARD LADDIE
IPC: A61B18/02
Filed: 1965-09-16
Abstract: 1,123,632. Surgical cooling apparatus comprising a cryoscopic probe. AEROJET-GENERAL CORP. 16 Sept., 1965, No. 39534/65. Heading A5R. Apparatus for treating living tissue, for example in cryoscopic treatment of the brain, includes a probe having an elongated hollow housing at one end of which is an operative tip portion adapted to be placed in proximity to the tissue to be treated. Carried by the probe to extend at least partially within the housing is a delivery tube having an open end in communication with the tip portion for delivering thereto a fluid which may have a temperature different from the temperature of the tissue to be treated; extending within the delivery tube is an elongated valve stem having a diameter which is smaller than the internal diameter of the delivery tube; carried by the end of the valve stem adjacent the open end of the delivery tube is a valve member which is receivable by the open end of the delivery tube to obturate partially or wholly the open end of the delivery tube, means being provided for inducing relative axial movement between the delivery tube and the valve member in order to vary this obturation thereby to regulate the rate of delivery of fluid through the delivery tube into the tip portion and hence to control the temperature of the tip portion of the probe. In addition to the probe, the apparatus may include a source of liquid refrigerant, preferably a source of warming fluid, conduit means for connecting the source of liquid refrigerant and (if present) the source of warming fluid to the delivery tube of the probe, and valve means in the conduit means for selectively controlling the rate of admission of liquid refrigerant and (if present) warming fluid from the source (or respective sources) to the tip portion of the probe in order to vary the temperature of the tip portion; it is preferred to provide a plurality of sources of liquid refrigerant together with associated conduit means and valve means, the sources containing refrigerants having different boiling points. As illustrated in Figure 1, fluid refrigerant or coolant is supplied to probe 10 from containers 13 and 14 via valves 15a, branch conduits 16a, manifold 16, flow control valve 18, filter 19, quick-disconnect pipe coupling 12 and tube 15; alternatively, refrigerant may be supplied to the probe from a source external to case 11 via external supply conduit 166 and valve 17. Warming fluid may be supplied to the probe from container 21 via branch conduit 21a, pressure regulator 23 and valve 24; the container is refilled via supply conduit 21b and valve 22. Manually operable and normally closed valve 25 serves as a venting or exhausting means for the manifold. As illustrated in Figure 2, the probe has a housing comprising a body portion in the form of a cylindrical tube 27 made for example of stainless steel. Surrounding one end portion of the tube is a thermal insulation covering 28 of for example PTFE; within this end portion of the tube is an evacuated or air-containing double-walled insulating jacket 29 to which is connected threadably and detachably a tip member 30 made for example of stainless steel. Rigidly secured to the tube is a cup 31 to which is threadably connected a cap member 32 having a threaded central aperture in alignment with a central aperture formed in the wall 33 of the cup. Passing through the aligned apertures and an annular sealing member 35 made for example of rubber is a delivery tube 34 to which is rigidly secured an annular collar 36 disposed within the cup to be movable therein in opposition to a coil spring 37. The axial position of the collar and hence of the delivery tube is adjustable by means of a manually rotatable wheel 38 having a threaded stem 38a which is received by the central aperture in the cap member; the collar is centred within the cup by guide sleeve 39. Rigidly secured to one end of the delivery tube is a socket member 40 to which is threadably connected a hollow plug 41 which is rigidly secured to the tube leading from the source or sources of fluid. Seated within the hollow plug is helically coiled spring end portion 45 of a valve stem 44 at the other end of which is a valve member 43 engaging the closed end of the tip member; the valve member has a varying cross-section and is enlarged with respect to the valve stem in order to obturate partially or wholly the other end of the delivery tube. Connected to the housing of the probe by a mocket 49 is a tubular jacket 26 through which pass wires 47 leading from a thermocouple 46 via pin connectors 48 and detachable mating socket connectors (not shown) to a temperature indicating mechanism 20 (see Figure 1) for indicating the temperature of the tip portion of the probe. Figure 3 (not shown) illustrates a probe of different construction, the tip member being fixedly attached to the housing of the probe and the valve member being in the form of a needle valve.