FAILED BACK SYNDROME
«Failed back syndrome» is a term often used to describe patients who have undergone lumbar surgery, but still have persistent pain syndromes. This is clearly not a diagnosis in itself but a term used to describe a large and diverse group of patients who have undergone a variety of lumbar surgeries, with unsatisfactory outcomes. Many investigators have attempted to discern a cause of these poor outcomes, in hope that it may be treated or prevented. For many, this search has become a quest for a «Holy Grail». Unfortunately, the causes, which include, among others, inappropriate patient selection for surgery, are so diverse as to preclude a single preventative or therapeutic solution.
It has long been thought by many that epidural fibrosis is one such cause. As a result, much work has been done to try to find ways of preventing its occurrence. Epidural fibrosis is an expected healing consequence after laminectomy. This extradural fibrotic tissue may extend into the vertebral canal and adhere to the dura mater and nerve roots, causing recurrent symptoms including pain, possibly leading to the failure of spinal surgery. Furthermore, epidural adhesions make reoperation of the same area technologically difficult and dangerous because the risk of nerve root injury and laceration greatly increases.
For any patient with a failed back syndrome, our first attitude will be to review the diagnosis of the disease, and then the treatment. It is possible that the patient has been treated of something that they did not have or that the outcome of treatment has not been successful. Most commonly, the spine has become unstable after removal of their bone tissue, or has not turned the implants and thereby non-union has occurred. Also there may be damage to the nerve roots established, which may or may not be reversible. In any case, therefore, the first thing we do is carefully review the case. If we find causes of pain, the treatment will go to the cause of them (very often the patient has segmental instability of the spine and need the practice a spinal fusion). Sometimes we find irreversible damage to nerve tissue and we apply techniques for treatment of chronic pain. Current science allows for many possibilities, from physical therapy or medications to more aggressive measures such as surgery. It is in this field that Neurosurgery may be of help.
Why does my back ache?
Back ache, or lumbago, may have many different causes, including muscle stress or abdominal diseases. However, it can also be due to the spine, possibly the intervertebral discs or even the spinal cord. In the latter cases Neurosurgery can be of great help.
In younger patients (20-40 years old) the origin is usually a disc herniation. They have backache plus sciatica (pain in the leg). Older patients (60-80 years old) usually have a facet hypertrophy and/or lumbar canal stenosis. The bone of the spine grows (osteoarthritis) with subsequent narrowing and rubbing of the nearby nerves, producing pain. Precise diagnosis of the origin of the pain is most important, as every condition needs specific treatment.
I HAVE A DISC HERNIATION. WHAT CAN I DO?
Treatment of this condition is less and less aggressive. Chemonucleolysis, microdiscectomy and disc endoscopy are the most common techniques in use today.
Chemonucleolysis consists in injecting a substance (chemopapain) into the disc which destroys it. Although it is usually performed under local anaesthesia this injection is quite painful; hence, we usually prefer an anaesthesiologist to administer the analgesics and monitor your vital signs.
The injection of ozone gas consists in injecting this gas into the damaged spinal disc and the surrounding muscles, thus helping to clear the inflammation of the nerve root and therefore the patient’s discomfort. It is not always effective, but when it is it avoids the need for a more aggressive treatment.
Microsurgery consists of the removal of the herniated disc with the help of a surgical microscope through a 2 cm incision. For your comfort we perform the operation under regional anaesthesia (from the waist downwards). The patient is either awake or lightly sedated during this procedure.
When endoscopy is used, a thin tube (the endoscope) connected to a camera and with some working channels lets us see the hernia and remove the disc. As with microsurgery, we prefer to do it under regional anaesthesia.
MY BACKACHE IS NOT RESPONDING TO DRUGS OR PHYSIOTHERAPY. WHAT CAN I DO?
Older patients usually have only backache, without sciatica.
The usual origin is that the bone of the spine has grown producing narrowing and rubbings in the nearby nerves, causing pain.
For many patients a facet denervation will suffice. It is an outpatient procedure which consists in the destruction of the small facet nerves which are being rubbed. A needle is introduced into the back until it reproduces the same pain that the patient has, and then radiofrequency waves are applied to destroy those nerves. The resulting relief can last from some months to several years, and can be repeated if necessary.
In other cases it is necessary to have a lumbar arthrodesis plus reshaping of the lumbar canal. With this surgery the arthritic bone which is rubbing the nerves is milled out, and afterwards the vertebrae are fixed with a metal framework (arthrodesis). The framework we use is made of a titanium alloy, which has optimum elasticity and resistance. Once fixed the vertebrae usually stops hurting.
Arthrodesis is a long operation (4-5 hours) which is usually performed with the patient face downwards. Some patients cannot stay in this position for so long (due to obesity, cardiac or lung problems… etc) and are considered unsuitable for the procedure in other institutions due to the high risk. In some of these cases, however, one solution is to perform the procedure with the patient lying on his or her side. This position requires greater surgical skill and prolongs the procedure for some 30 minutes; however, it also reduces some complications and allows this surgery in patients whom otherwise can only receive conservative treatment.
Will the postoperative period be painful?
This surgery is usually painful for the first 48 hours and the anaesthesiologist will give you special treatments, apart from the normal analgesics. The two methods more frequently used are intrathecal analgesic and PCA pump.
If intrathecal analgesic is used you will receive a strong analgesic in the CSF before surgery is started. The effect starts 6 hours afterwards and lasts for 36 hours, giving great comfort in the first two days, which are the worst of the postoperative period.
The PCA pump is a small computer with a button and a bag which contains the analgesic and is connected to a vein. Every time you press the button you receive a given amount of analgesic. Although you may press the button as many times as needed there is no danger of overdosing, as the computer has programmed limits determined by your weight, age and the surgery undertaken.
How long will I be in hospital?
After a lumbar arthrodesis the patient is usually discharged between the 4th and 6th day, depending on the number of vertebrae levels operated on, how well the operation went and how well you recover from surgery.
What are the main complications?
The most usual complication is bleeding, which sometimes needs a transfusion.
If you wish, you can be your own donor (auto-transfusion), but you must tell us at least five weeks in advance. In this case we will take some of your blood once a week for four weeks and you will have to take some drugs to enhance blood formation.
If you do not wish to be transfused, even with your own blood, you must also inform us at least six weeks in advance so that we can prepare your body for the operation. In this case the anaesthesiologist will inform you in detail about what s/he will do and the conditions for surgery.
Other possible, though less frequent, complications arise from the face downward position maintained during the operation, mainly cardiac or lung problems or nerve compression. Of course, both the surgeon and the anaesthesiologist will do what is necessary to reduce the possibilities of complications, and treat them as soon as possible if they appear.
WHAT RESULTS CAN YOU EXPECT?
Surgical treatment of disc herniation is very effective from just after the operation. Once the origin of the pain is removed (hernia), the leg pain usually disappears, although a little low back pain can remain, due to slight spinal instability created by removing the disc.
Facet denervation is a procedure with transient results, lasting between some months and several years. The aim is to delay more drastic surgery in patients who are not so old.
Lumbar arthrodesis also has very favourable results, with relief of pain for some years. Some patients have progression of their arthritis and some years after the operation the vertebrae above the operated levels start hurting. Usually the problem is solved with a facet denervation, although occasionally it may be necessary to re-operate, removing the previous material and inserting a new arthrodesis over more levels,
IN SUMMARY
The most important fact in failed back syndrome (backache) is the clinical diagnosis of the cause of the pain. There are many and varied options for the treatment of failed back syndrome, depending on the origin of pain. Even in difficult cases, your doctor can always make an assessment and consider the different possibilities for treatment.