Other instruments for use with the Exeter Hip System
Retractor Aspirator for use with cemented sockets
Description
A cannulated retractor to be inserted into the body of the ilium during cemented total hip replacement. The device acts as a retractor and in addition, it can be used to suck cement into the pelvic bone and also blood out from the body of the ilium during cementing of the acetabular component.
Instructions for use
The retractor may be inserted at any time prior to cementing the socket. The inner obturator is sharp and should therefore pierce the outer cortex of the ilium without difficulty. The ideal position is for the tip of the aspirator to be sited 1.5 to 2 centimetres proximal to the deepest acetabular drill hole. The obturator may be left in place if the device is used solely as a retractor. Prior to lavage of the acetabulum and cementation of the socket, the obturator can be removed and suction applied to the retractor. This will then help suck the lavage fluid away during cleaning of the trabecular bone in the acetabulum. It will vent the cavity if hydrogen peroxide soaked swabs are used. After cement has been inserted and during subsequent pressurisation of the cement and insertion of the socket, the suction applied will help keep the interface free of blood thus helping to create sound mechanical fixation of the acetabular component. It also encourages intrusion of cement into the trabecular bone of the ilium.
Warnings
- Insertion of the Retractor Aspirator: The stop on the shaft of the retractor is designed to stop the instrument from penetrating too deeply into the bone; however it should not be relied upon as an indication of the optimum depth of penetration. Care should be taken that the instrument tip does not penetrate the inner cortex of the ilium.
- Blood Loss: The Retractor Aspirator is designed to remove excess blood from the cement-bone interface. If there is copious bleeding from the bone it is possible to aspirate a large volume of blood through the aspirator. The surgeon is advised to titrate the degree of vacuum applied and to check at regular intervals the amount of blood being removed by the aspirator. If this is thought to be excessive then use of the device should be discontinued.
- Excess cement: The device is designed to facilitate the penetration of cement into trabecular bone in order to improve the quality of the cement-bone interface. In osteoporotic patients it is possible for the aspirator to suck as excess of cement into the bone of the ilium. In cases where the trabecular bone structure is very open it may be advisable to turn down the degrees of suction applied to the device.
Instruments to be used to enhance exposure through either conventional or Mini-(MIS) incision*
A set of instruments to provide enhanced access to the acetabulum and femur have been developed for use with the cemented Exeter Hip system. The instruments consist of:
- Extended metal backing-plate into which the nozzle of the gun is introduced prior to insertion of cement and pressurisation of cement in the femur. A handled metal backing plate for the sorbothane horse-collar pressurisers is also provided.
There is a choice of three femoral elevators to allow access to the proximal end of the femur. If desired the jaws of one of the forks may be placed either side of the ilio-psoas tendon or lesser trochanter. Usually two of the three elevators are introduced to give good access.
An anterior retractor is introduced over the anterior column during exposure of the acetabulum. An inferior retractor is provided to go inferiorly under the transverse ligament and there is a spare Hohman type retractor. The double-ended curved instrument is designed to go under the abductor muscles (posterior approach) and retract these out of the way to give direct access to the proximal femoral canal.
The sucker-aspirator device is described elsewhere (vide supra).
Please see section on the Mini-incision approach to the Hip for further description of the surgical technique using these instruments.
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