Removing giant cell tumors of the sacrum (bone at the base of the spine) can be dicey work. Taking the entire sacrum and tumor can leave the patient with unpleasant changes in bowel and bladder function due to nerve damage. But anything less can mean the tumor will come back. If the sacral nerve roots aren’t removed, tiny tumor cells left behind may cause tumor recurrence.
Giant cell tumor (also known as giant cell myeloma or osteoclastoma) are seen under the microscope as having large bone-like cells with more than one nucleus (center). Giant cell tumors affect the distal ends of long, tubular bones such as the femur (thigh bone at the knee) and radius (forearm bone at the wrist) most often.
Such tumors of the sacrum are uncommon. They are usually benign but they can grow very large putting pressure on the nearby nerves and other soft tissues. Sometimes they do become malignant and metastasize to the lungs. Giant cell tumors occur more often in Chinese people (up to 20 per cent of the population are affected) compared to Caucasians in Western countries.
In this study from China, researchers proposed that conservative surgery with good control of bleeding would reduce the rate of tumor regrowth or recurrence. Conservative surgery refers to sparing (partial removal) of the nerve roots when the tumor is located at the S3 sacral level and below. By leaving the S3 sacral nerve root intact, bowel and bladder function can be maintained. Tumors involving S1 and S2 can be completely excised (cut out).
Using special hemorrhage control measures during the surgery reduced the risk of tumor recurrence. Intraoperative occlusion of the abdominal aorta was the method used to control bleeding. The aorta is the large blood vessel (artery) that delivers blood from the heart down to the legs.
The method for bleeding control required several steps. First, the arteries were mapped out using an arteriograph. This procedure involved injecting dye into the blood vessels and viewing them on a special real-time X-ray called fluoroscopy. Arteries were closed during the operation by encircling them with nylon tape until no blood could be seen passing through.
In order to get to the tumor, various sacral and pelvic muscles were cut. The bone was also cut through at the level of the tumor. Once these musculoskeletal tissues were out of the way, the tumor could be located.
Limiting bleeding made it possible for the surgeon to see the outline of the tumor and remove it without contaminating (spreading) tumor cells in the area. Surgical sponges were packed around the outside of the tumor to keep any cells from spilling into the area.
In every patient, the fourth sacral nerve root (S4) was killed on both sides. Whenever possible, they left at least one, if not both, of the S3 sacral nerve roots alone. For patients with S3 nerve damage or loss, intermittent catheterization and bowel medications were often required. Catheterization refers to the use of a thin plastic tube inserted into the bladder to remove urine. Intermittent means the catheter is not left in place but just used when needed.
If too much bone had to be removed that the sacral spine became unstable, then a spinal instrumentation system (rods and screws) were used to support the spine. When the procedure was completed, the nylon tape was slowly removed from around the blocked blood vessels and blood flow was gradually restored.
Although the primary focus of the study was the rate of tumor recurrence following surgery with intraoperative hemorrhage control, the authors collected data of all kinds on the patients to use in the analysis. Information on the tumor included location, size, and involvement of sacral nerves. Information from the surgery itself included amount of blood loss, level of sacral nerve roots left intact (spared any surgical damage), and method used to control hemorrhage during the operation.
Data collected on the patients included age, gender, symptoms and how long the patient had those symptoms. The most common symptoms were low back, buttock, and/or leg pain; and changes in bowel and bladder function. Complications from the surgery were also recorded. Almost half of the group had some problem such as deep vein thrombosis (blood clots), wound infections, wound dehiscence (delayed wound healing with surgical site re-opening), or cerebrospinal fluid leakage.
Compared to the results reported for other studies, this study had a low tumor recurrence rate (29 per cent instead of 47 per cent). The authors give the credit to better control of intraoperative bleeding. The patients in their study had much lower blood loss compared to patients in other studies. They also pointed to the use of a new operative instrument (Helix Hydro-Jet) for quickly and easily removing the tumor with little to no damage to the nearby nerves or blood vessels.
By preserving both of the S3 nerve roots, bowel and bladder problems were avoided for almost everyone. Even when only one S3 nerve root could be spared, bowel and/or urine function was present in more than half the group.
The authors concluded by recommending conservative surgery with partial removal of important sacral nerve roots. This approach can reduce neurologic problems affecting bowel and bladder function. Using a blood saving method of complete occlusion of the abdominal aorta is advised to limit bleeding during the operation. With less blood in the surgical site, the surgeon has a clear view of the tumor and can remove it more carefully and completely.