A system for insufflation and recirculation of insufflation fluid in a surgical procedure, the system (1400; 1500) comprising a trocar (100, 1401) and a control unit having an input port and an output port; the trocar (100, 1401) having: a) an elongated body defining a lumen therein; b) a nozzle operatively associated with the elongated body for directing pressurized fluid into the lumen; c) a fluid return plenum adapted and configured to collect spent insufflation fluid; d) a nozzle supply port in fluid communication with the nozzle, for delivering a pressurized flow of insufflation fluid to the nozzle, adapted and configured to receive pressurized insufflation fluid from the output port of the control unit; and e) a fluid return port in fluid communication with the fluid return plenum, adapted and configured for returning insufflation fluid from the trocar to the input port of the control unit; and the control unit having: a) a fluid pump (1550; 2750) adapted and configured to circulate insufflation fluid through the system, the fluid pump having an input and an output; b) a supply conduit (1483, 1583; 2783) in fluid communication with the output of the fluid pump and configured and adapted for delivering pressurized insufflation fluid to the output port of the control unit; c) a return conduit (1485, 1585; 2875) in fluid communication with the input of the fluid pump for delivering insufflation fluid to the fluid pump and configured and adapted for returning insufflation fluid to the input port of the control unit; and d) a pressure-controlled valve (1560; 2760) in fluid communication with the supply conduit and the return conduit, the pressure-controlled valve being adapted and configured to receive a control signal that depends on overpressure in the patient's abdominal cavity and respond to the control signal by opening, and/or being a back-pressure control valve adapted and configured to respond to a sensed overpressure condition in the supply conduit by opening, thereby fluidly connecting the supply conduit and the return conduit with one another, wherein in absence of the control signal and/or in absence of the sensed overpressure condition in the supply conduit, respectively, the pressure-controlled valve (1560; 2760) remains in a closed state. a) an elongated body defining a lumen therein; b) a nozzle operatively associated with the elongated body for directing pressurized fluid into the lumen; c) a fluid return plenum adapted and configured to collect spent insufflation fluid; d) a nozzle supply port in fluid communication with the nozzle, for delivering a pressurized flow of insufflation fluid to the nozzle, adapted and configured to receive pressurized insufflation fluid from the output port of the control unit; and e) a fluid return port in fluid communication with the fluid return plenum, adapted and configured for returning insufflation fluid from the trocar to the input port of the control unit; and a) a fluid pump (1550; 2750) adapted and configured to circulate insufflation fluid through the system, the fluid pump having an input and an output; b) a supply conduit (1483, 1583; 2783) in fluid communication with the output of the fluid pump and configured and adapted for delivering pressurized insufflation fluid to the output port of the control unit; c) a return conduit (1485, 1585; 2875) in fluid communication with the input of the fluid pump for delivering insufflation fluid to the fluid pump and configured and adapted for returning insufflation fluid to the input port of the control unit; and d) a pressure-controlled valve (1560; 2760) in fluid communication with the supply conduit and the return conduit, the pressure-controlled valve being adapted and configured to receive a control signal that depends on overpressure in the patient's abdominal cavity and respond to the control signal by opening, and/or being a back-pressure control valve adapted and configured to respond to a sensed overpressure condition in the supply conduit by opening, thereby fluidly connecting the supply conduit and the return conduit with one another, wherein in absence of the control signal and/or in absence of the sensed overpressure condition in the supply conduit, respectively, the pressure-controlled valve (1560; 2760) remains in a closed state.