Agustín Muñoz was 33 when he had a serious motorbike accident. He is lucky to be alive, because apart from breaking several bones his humeral artery was severed and he would have bled to death if he hadn't been rushed to hospital in time. But the worst was yet to come. After several operations his left arm was still immobile and the breakage of the brachial plexus - the structure which innervates the upper limbs - left him in great pain. Perhaps that is an inadequate description: "It was completely unbearable. Day and night. Week in, week out. There were times when I thought I was going mad. The pain made me want to throw myself off the balcony," he says.
Reluctant to take very strong analgesics because of their side effects, Agustín's ordeal lasted six years until, last summer, a neurostimulator was implanted beneath his skin. It uses electrical impulses to mask the pain to such an extent that it is almost eliminated completely. He says it has saved his life.
For him, and for hundreds of others with neuropathic pain as the result of an injury or illness of the nervous system which does not respond to conventional treatment, life can seem intolerable. For example, trigeminal neuralgia, which is one type, is known as the 'suicide disease'.
Dr Jesús Maldonado, an anaesthetist and the head of the Pain Unit at the Parque Tecnológico de la Salud (PTS) hospital in Granada, who looks after Agustín, explains that medullary stimulation technology began to be developed in the 1960s and has evolved to become an effective alternative for patients with relatively localised neuropathic pain, generally in the back, neck, legs or arms.
"It is very important to select the candidates for this procedure carefully: they are usually patients who have had spine surgery but whose condition has worsened and they can't have any more operations, those with complex regional pain syndrome and those who have suffered nerve injuries as a consequence of serious traumatisms or amputations in accidents at work or traffic," he explains.
Similar to a pacemaker, the neurostimulator is implanted in the abdomen or dorsal area and transmits electric signals through a cable in the vertebral column. Depending on the place affected, the electrodes are placed at a different height on the spinal cord. Their function is to "fool" the brain by blocking the pain signals and replacing them with a "pleasant tingling" sensation. A new version of the generator, called "sub-threshold", produces no sensation at all; it simply calms the suffering.
For Juana Hervás, who is 74 now, the ordeal began 18 years ago. "It just happened overnight," she says, and for no apparent reason. In Juana's case, it affected the perineal and genital area. Ravaged by pain, and after seeing digestive specialists and gynaecologists without success, she ended up in the psychiatry unit, but that didn't help either. She visited private doctors all over Spain until finally one in Burgos found the answer: a trapped pudendal nerve.
This is a syndrome which quite often occurs in cyclists, because of the compression of this area against the saddle, but it can also originate in childbirth or even in people who spend a lot of time sitting down. The symptoms include numbness, painful sexual intercourse and difficulty in defecating.
However, in Juana's case, the operation failed. She was taking numerous tablets but they hardly made a difference. She was in pain when sitting and standing, but walking and lying down helped a little. Doing housework was extremely painful; but not now. A few weeks ago they implanted her neurostimulator and now, instead of pain, she notices a tingling. She has been taught how to regulate it with a remote control when changing position, so the paresthesia doesn't cause discomfort. She is now getting used to her "guest" and doesn't want to be without it. "I felt better straight away. I went to mass for the first time the other day, and I have started to go shopping again," she says. She is happy, but still cautious; she says she still can't quite believe it.
Sinking into depression
Antonio Castillo becomes tearful when he remembers how he felt just one month ago: depressed, drugged and, despite the medication, in pain. "I was in a bad way," he admits. Two years ago he broke the biceps in his right arm, trying to stop his sister-in-law, who had just learned that her mother had died in hospital, falling to the ground as she fainted. He had an operation, but the injury to the antebrachial cutaneous nerve was agonising. Not even the increasing doses of morphine he was given could ease the pain he felt from his neck to the tips of his fingers. The side effects, he says, were "horrible": tiredness, lack of reflexes, bloating and sexual dysfunction. "The pain was waking me up several times a night. Then I'd spend all day lying down, getting more and more depressed. My wife tried to cheer me up, encouraged me go out of the house, but I just couldn't do it," he says.
Antonio was unlucky. The deterioration in his right arm, which he can hardly lift, came on top of a nerve injury which was caused by crushing ten years previously, and since the accident he has been unable to return to his job in a sports shop. Now, aged 51 and with three children, he is waiting to be seen by the Social Security Medical Tribunal. "Your life changes completely. You are in unbearable pain day after day after day," he says.
When Dr Maldonado suggested implanting the medular stimulator a couple of months ago he agreed, but without much hope. "It has completely taken away the pain; all I feel now is a sort of tingling, like pins and needles," he says. It was worth trying. "I can do a lot more now, and emotionally I feel much better. More people should know about this," he says.
Agustín Muñoz's motorbike accident also left him with serious problems. "I have lost the use of one hand altogether," he explains. After an unsuccessful operation in Seville, the famous surgeon Pedro Cavadas, from Valencia, removed a muscle from his leg and transferred it to his biceps area. He is confident that once it has gained strength and volume, he will be able to flex and extend his arm again. "We're working on that," he says, optimistically.
Freeing himself from the pain that tortured him has been a giant step. In his case, aged just 40, with a job and a passion for sport, he felt particularly incapacitated. "I have always hated taking medication, but ended up taking eight or ten really strong tablets a day. You feel drugged. You can't concentrate properly, it affects your life. You're not the same person any more," he says. Now, he only takes one tablet a day. He has been able to continue his job with a drinks distribution company, "but when the weekend comes and you drop your guard, you go mad," he says. His mountain bike also helps; he rides it one-handed with his injured arm in a sling: "It hurts less when I'm on the bike" he says. "I refused to let myself get depressed. I am a strong person, but sometimes it felt like my arm was going to explode. It's very hard to suffer unbearable pain 24 hours a day." His device has reduced the pain by about 80 per cent. "If anyone had told me that was possible, I wouldn't have believed it," he says.