Implants maker reduces machine times by up to 70%

A world leader in limb salvage has seen machining times reduced by up to 70% since investing in CAD/CAM 3+2 axis machining software that covers more complex workpieces.

Stanmore Implants Worldwide specialises in supplying a state-of-the-art implant service for bone tumour limb salvage and complex joint replacement, combining advanced research with practical clinical experience.

In 1949, the first custom-made acrylic joint replacement to be used in the UK was designed and fabricated at the Centre for Biomedical Engineering, University College London, which later led to the 'Stanmore Hip'.

CADCAM software was introduced into the department in 1988, producing 3D models from digitised radiographs and then machining the implants from titanium alloy bar.

The first femoral hip joint produced using CADCAM software in 1989 was much more precise than those previously made by hand, giving patients a much improved fit, which increased the success rate of the replacement surgery.

In 1996, Stanmore Implants was created from the Centre as an implant design and manufacturing company, to provide a rapid 'on demand' service.

The cost-effective design and manufacturing processes adopted by Stanmore Implants, enable them to provide the best possible customised implants for little more than the cost of a standard implant - a cost that is more than offset by the improved performance and long term clinical results.

Patients who have bone cancer often require radical and extensive surgery in a very timely manner.

The surgeon and patient have very few options as the diseased bone needs to be taken out.

Prior to the development of the limb salvage implants pioneered at the Centre, amputation of the limb was often the only form of treatment.

Today although some amputations do take place (due to the spread of the cancer outside the bone) the majority of patients receive a large metal bone replacement implant.

Due to the very rare nature of bone cancers, the wide range of skeletal locations and the age of patients (2 yrs to over 90 years of age) custom-made (patient specific) implants are often ideal.

One of the major disadvantages of custom-made implants is the time required to both design and manufacture.

Frequently the surgeons require the surgery to take place within weeks of the initial diagnosis.

In recent years, due to the significant improvements in chemotherapy and imaging of the cancer, surgeons will delay making their decision on the amount of bone to be removed as they are waiting to see the effects of the treatment.

The benefit to the patient is that less bone may need to be resected.

Unfortunately for manufacturers, the delay in decision-making may result in the lead time for a custom-made implant being as little as a few days.

In addition, the improvements in imaging of the cancer permit the surgeon to delimit the tumour much more accurately.

Tumours in bone do not always extend into the joint and in 20-30% of cases the joint can be left - this is joint saving or joint sparing surgery.

It is much better for the patients to retain their joint, as the one nature has produced is phenomenally good.

Joint sparing surgery requires much more complex design and manufacturing capabilities and it has been through the introduction of sophisticated software that Stanmore Implants have been able to produce joint saving designs.

In 2004, Stanmore Implants invested in NC Graphics' Depocam software and Depo tooling; it was clear from cutting trials that further time savings could be achieved.

Some machining operations were reduced by 50%.

A joint saver that had previously taken 8 hours to machine was reduced to only 4 hours, and hip shell machining was also halved, from 9 hours to 4.5 hours.

Drilling operations were reduced by a massive 70%, taking just 6 minutes compared to 20 minutes previously.

With the 3+2 machining available in the Depocam software, Stanmore Implants is now able to manufacture even more complex joint replacements, as well as produce the surgeon's cutting guide formers for accurate bone machining, ensuring a perfect fit with the bespoke replacement.

Always at the cutting edge of technology, Stanmore Implants using Depocam, has for the first time been able to produce devices such as a bone replacement for one of the small bones in the finger, an implant for the thumb, and eye socket implants that will permit the attachment of a false eye, all of which have been successfully implanted in patients.

"Patients who've received the joint sparing prostheses exhibit much better function, have a much more natural mobility and often do not have any form of disability or show signs of a limp," said Dr Paul Unwin, managing director of Stanmore Implants.

"Each year we are producing more and more sophisticated implants with shorter lead times and this can only be achieved by the utilisation and integration of computer based design and manufacturing, such as Depocam.".

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