Nerve blocks are one of the most common procedures for pain in cancer patients. For this purpose, a thin needle is inserted from the skin into the bundle of nerve fibers (ganglion), which causes the pain and some substances such as alcohol, phenol is given to destroy the nerves in this region. These process, called "neurolysis", is performed under the guidance of ultrasound, tomography or fluoroscopy with local anesthesia. The most commonly used nerve blocks in cancer patients are celiac ganglion block and hypogastric ganglion block which are applied for the pain due to cancers in the abdomen.
Celiac ganglion block:
It is the most common nerve block in cancer patients. Celiac ganglia are found on both sides of the midline between celiac and mesenteric vessels feeding the stomach and intestines, and in most patients they can be seen directly on computed tomography. The nerves of many abdominal organs (esophagus, liver, gallbladder, spleen, pancreas, kidney, small intestine) have connections with the nerves in celiac ganglia. Therefore, by the destructing the celiac ganglia, the pain from these organs may be eliminated or markedly reduced.
The celiac ganglion block was first considered by Kappis in 1914, but it was first administered by Dr Jones in 1957 with the injection of alcohol. Initially, fluoroscopy was performed, followed by ultrasound and finally by computed tomography (CT) . Nowadays, celiac ganglion block is mostly performed under CT guidance, because celiac ganglions, surrounding organs and needle are very well seen and spread of the alcohol around the ganglion can be easily monitored, which increase the safety and efficacy of the procedure.
How is it done?
Celiac ganglion block can be performed by putting the needles from the anterior or posterior part of the abdomen. The most common approach is to insert two needles from the back, but in some cases more needles can be used. For the procedure, the patient is placed prone (face down) on the tomography table and mild sedation is performed. Then, on CT images, the locations of the celiac ganglia are visualized and the point where the needles are placed from the skin is determined. After anesthetizing the skin with local anesthesia, two very thin needles are advanced from both sides to the celiac ganglia. When it is seen that the needles reach the celiac ganglia, a small amount of contrast material is given to control the spread of the drug and then the local anesthesia is given to prevent the pain. Reduction of the patient's pain upon local anesthesia can be considered as a sign that the procedure will be successful. After making sure that the needles are in the right place, "neurolysis" is performed by giving pure alcohol (40-60 ml totally) from both needles
Side effects (complications)
After celiac block, the patient is hospitalized for at least 12 hours and may be discharged if there is no problem. Celiac ganglion block is generally a safe and effective procedure and only 1-2% of patients develop severe complications. Mild complaints such as pain, low blood pressure and diarrhea may occur after the procedure. After the block, the pain may be on the back and shoulders and last for 2-3 days. Low blood pressure after celiac block is observed in about one third of patients, is temporary and improves with bed rest, but in some cases intravenous fluid may be required. Diarrhea is also observed in approximately one-third of the patients and resolves spontaneously.
Which tumors are suitable?
Celiac ganglion block is most commonly applied to pain related to pancreatic and gastric cancer. However, it can be used in tumors originating from any organ in the upper abdomen (spleen, kidney, liver, gallbladder, small intestine, etc.). Celiac ganglion block may cause pain reduction or loss in approximately two-thirds of patients, but may be ineffective in one third. The most important reason for the ineffectiveness of the blockage is that the tumor surrounds the ganglia and prevents the alcohol from reaching the ganglia. In such patients, alcohol can sometimes be injected directly into the tumor. However, this is a risky procedure and it is preferable to perform tumor ablation by thermal methods such as radiofrequency and cryoablation. Especially in pancreatic cancers, cryoablation should be considered in the first place because of its safety and direct destruction of the tumor as well as damage to the nerves. In some centers including ours, cryoablation has been used instead of alcohol for the celiac ganglion block with successful results. In resistant cases, pancreatic cryoablation and celiac ganglion block (with alcohol) can be used in combination and better results can be obtained in terms of pain relief.
Celiac ganglion block is usually performed if the pain in the patient cannot be resolved with morphine-like narcotic pain relievers. However, at this stage, the ganglions may already be wrapped by the tumor and the alcohol may not reach the ganglia. Therefore, the patient may not benefit from the procedure. Thus, celiac ganglion block may be more appropriate in the early stage of pancreatic cancer, when the ganglia are not completely attacked and the patient is not yet feeling unbearable pain. In the literature, it has been shown that if the celiac ganglion block is performed early, the pain relief lasts longer, the quality of life increases more and even the side effects of the narcotic drugs such as morphine decrease and even the survival of the patient may be prolonged.
Hypogastric ganglion block:
Hypogastric ganglion block is used for the pain caused by tumors of the lower abdomen (pelvis) including bladder, prostate, uterus, vagina, ovary, urine channel, testes and tumors of the large intestine. The hypogastric ganglia are located in front of the L5 and S1 vertebrae and aorta, which is the main artery in the abdomen. Tomography and fluoroscopy are the ideal imaging modalities for blocking. The procedure can be done from the posterior or the anterior abdominal wall.
How is it done?
For hypogastric ganglion blockade, either the patient is placed in a prone position and entered with two needles from the right and the left, and the needles are guided by tomography guidance to the ganglia. Or in supine (face up) position, a single needle is inserted and guided to the L5-S1 vertebra under fluoroscopy. When the ganglia are reached, a local anesthetic is given, just like in celiac ganglion block. In most patients, pain may be lost. Then 20-40 ml of pure alcohol is given into the ganglia (neurolysis) and the procedure is terminated.
What are the complications?
Hypogastric block is an extremely safe procedure. Severe neurological problems have been reported in only one patient so far in hundreds of studies reported in the literature. Hypogastric ganglion block, as in celiac block, eliminates or markedly decrease the pain in approximately two-thirds of patients. In the remaining one third, it may not be successful.
Interventional oncology in cancer management
Prof Saim Yilmaz, MD