Circulating a liquid through a joint

An apparatus for circulating a physiological liquid at a pressure and flow rate through a body cavity for an endoscopic resection or examination of the cavity, the apparatus comprising:

• a source of the liquid;
• an input pump connected to the source and having a feed conduit for extending into the cavity for supplying the liquid to the cavity;
• sensor means for detecting pressure in the cavity and for generating an output corresponding to the detected pressure;
• generator means for generating an output corresponding to a reference pressure;
• means including an input-pump comparator connected to the input pump and having inputs connected to the sensor means and to the generator means for receiving the outputs therefrom and for operating the input pump such that the detected pressure corresponds at least generally to the reference pressure;
• a suction pump having a main suction conduit extending into the cavity for aspirating the liquid therefrom;
• suction control means for operating the suction pump at a predetermined generally uniform rate;
• a tool insertable into the joint;
• an auxiliary suction conduit having an end opening at the tool and an opposite end;
• and
• valve means having an output connected to the suction pumps and two alternately selectable inputs, one connected to the main suction conduit and the other to the auxiliary suction conduit, the valve means being movable between a position connecting the suction pump to only the main suction conduit and a position connecting the suction pump to only the auxiliary suction conduit.

In an endoscopic procedure wherein a liquid is fed into the joint from a feed pump through a feed conduit and is drawn out of the joint by a suction pump through a main suction conduit and wherein a tool carrying one end of an auxiliary suction conduit can also be inserted into the joint and the auxiliary suction conduit is connectable to the suction pump, the method comprising the steps of:

• operating the suction pump at a rate corresponding to a generally constant low rate of flow in the suction conduit when the suction pump is connected to the main suction conduit;
• increasing the suction-pump rate to a predetermined relatively high rate when the auxiliary conduit is connected to the suction pump;
• detecting the pressure in the joint;
• and
• operating the feed pump in accordance with the detected pressure in the joint to maintain the pressure above a predetermined desired level.

An endoscopic examination/resection apparatus comprising:

• a source of a physiological liquid;
• means including a feed pump and a feed conduit insertable into a joint for feeding the liquid to the joint;
• means including a suction pump and a main suction conduit for drawing the liquid out of the joint;
• a tool insertable into the joint and carrying one end of an auxiliary suction conduit;
• valve means between the suction conduits and the suction pump for connecting the suction conduits alternately to the suction pump to withdraw liquid from the joint through the conduits;
• suction-pump control means for operating the suction pump at a rate corresponding to a generally constant low rate of flow in the suction conduit when the suction pump is connected by the valve means to the main suction conduit;
• speed control means for increasing the suction-pump rate to a predetermined relatively high rate when the auxiliary conduit is connected by the valve means to the suction pump;
• and
• feed-pump control means for detecting the pressure in the joint and for operating the feed pump in accordance with the detected pressure in the joint to maintain the detected pressure above a predetermined desired level.