Jun 14, 2016 | By Alec

The Chinese medical world is increasingly becoming known for their very open approach towards innovative 3D printing solutions, and this was again emphasized during a ten-hour surgery in the Beijing QingHua ChangGeng Hospital on May 20. Led by professor Xiao Song Hua, physicians Song Fei and Zhao Zhe successfully completed the world’s first high-sacral en bloc resection that involves a 3D printed sacrum implant. During the surgery, a gigantic tumor was removed from the sacrum – the bone in the middle of the pelvis – of a father of two. The surgeons subsequently implanted a 3D printed prosthesis that provides pelvic stability and returns normal bowel and bladder functions.

The patient in question is in his thirties and is the father of two children. After suffering from back pain and a lack of mobility, doctors discovered a huge bone tumor on the upper part of his sacrum in April, with the pain being caused by the tumor pressing down on a nerve. This is quite a problematic condition, as the sacrum is absolutely crucial for normal movement. It fuses together five sacral vertebras and connects the spine and the pelvis, thus playing a huge role in connecting the torso to the lower body.

To be sure, treatment methods already existed but these are either risky or do not provide desired results. As professor Xiao explained, doctors often perform an Excochleation operation, which is quite simple but features a high cancer recurrence rate. Sacrectomy pelvic ring reconstruction is another option and can cure the cancer, but it’s so complex that few surgeons can perform it. It also requires cutting off the sacral nerve, which can result in numerous complications, including lower limb paralysis, incontinence and sexual dysfunction.

After discussing the options with the patient and his family, professor Xiao and his team therefore decided to explore a third method – one that would not only cure the cancer, but would also maximize the patient’s quality of life after surgery. Ultimately, they settled on a 3D printed prosthesis implant that minimizes post-surgery complications. But this method does involve three major challenges: the high precision with which the sacral tumor resection needs to be performed, the accuracy with which the 3D printed implant needs to be placed, and the long surgery times that are required.

Professor Xiao Song Hua.

But they first focused on 3D printing the pelvis implant, which was made by the 3D printing team of the QingHua ChangGeng Hospital. Using the patient’s CT scans and MRI results taken during preoperative preparation, they built a digital model of the pelvis. Through a series of calculations that took clinical conventions and expected results into account, they designed a model that would perfectly replace lost sacrum section. In contrast to general purpose artificial vertebrae, the prosthesis has been completely customized and featured a unique locking mechanism to hold it in place. 3D printed in titanium, it was also repeatedly tested for biocompatibility.

As the sacrum is located near to numerous vital organs, connected to the illium and close to several major blood vessels, it was also very likely that major bleeding would occur during the surgery. To minimize that as much as possible, the head of the hospitals’ vascular surgery department Wu Wei Wei embolized various arteries on the day before the surgery. To compensate, Director Ma Hai Mei from the blood transfusion department provided 20 units of red blood cells and 20 units of fresh plasma. Physician Zhao YanJun and Zhang Huan, the director of anesthesia department, prepared the patient’s anesthesia.

Everything was set for the surgery, which comprised of three steps. First, surgeons would have to protect the internal organs and blood vessels as much as possible. After the belly is opened and the bilateral retroperitoneal separation is performed to protect the tissue, they needed to determine the location where the bone will be cut on the front. This needed to take place at the L5 S1 gap, at the edge of the S2 sacral vertebrae hole and at both sides of the sacroiliac joints. This enables them to fully resect the complete tumor tissue, while reducing the likelihood of recurrence.

For the second step, the surgeons needed to follow the L345 line on the back of the patient and remove the vertebral plate which was not involved in the resection. During the third step, the surgeons moved to the front again to completely remove the vertebra and S1 nerve on the right side of the tumor, and build a bypass. Finally, they embedded the 3D printed prosthesis using the custom locking system.

This exhausting and invasive surgery was finally completed at 2 AM on May 20. During the extensive surgery, nurses changed shifts three times and the patient’s body needed to be turned over twice. During the ten-hour procedure, no vital sign fluctuations occurred, and the patient woke up a few hours after extubation. Fortunately, the father of two is recovering rapidly. Right now, a few weeks after the surgery, he is already walking and can visit the bathroom by himself. Most importantly, X-rays have shown that the prosthesis is still a perfect fit and doing exactly what it needs to do.

 

 

Posted in 3D Printing Application

 

 

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