By Colin Michie
“I’ve learned that even when I have pains, I don’t have to be one.” ––Maya Angelou
We are covered in pain detectors – found across every few millimetres of skin, with even more on the fingertips, lips and face. Pain signals race from these, after a graze or burn, at up to 30 metres a second, along nerve fibres thinner than a hair into the spinal cord. Pain relays to brain areas associated with emotions and memories. In those instants, describing pain has no words. It can take over our thinking, transforming our behaviour and social interactions as Maya Angelou described.
Pain is part of life, keeping us safe. Without it, we cannot recognise the risks of trauma. Children born with pain detectors that do not work – a rare problem – severely damage their lips, hands and limbs. We differ in our thresholds for feeling pain and favourite treatments. Perhaps cursing is effective for you (!), or applying cold to the site of pain? How about using music or meditative methods? Mechanical or electrical devices can stimulate nerves in various ways and can reduce pain signals. Acupuncture can reduce pain and anxiety.
Mothers in labour find relief in many routines including hydrotherapy. Systems of virtual reality are being tested in some Hospitals to find if these can be effective in diverting our brain’s focus on pain. Infants and small children respond to cuddling, sugar on a pacifier, sounds of a maternal heartbeat, or a lullaby.
Dentists moved in the nineteenth century from using herbal sedatives or alcohol to ether, chloroform or nitrous oxide, breathed through a mask. Patients lost consciousness, but continued to breathe. This general anaesthesia revolutionised surgery – planned and controlled techniques gave significantly better results. Intravenous anaesthetics added to inhaled ones; muscle relaxants and oxygen improved safety and control. But this was general anaesthesia – treatments kept patients awake – local anaesthesia?
Centuries before, Spanish doctors knew that coca leaves were sometimes used by South Americans to treat toothache. Once cocaine had been isolated from coca leaves, its anaesthetic effects were employed as local anaesthetic for eye operations in Vienna – it numbed eyes well. Cocaine as drops, or when injected with early hypodermic needles, caused alarm. It was a good pain-reliever – and patients remained conscious – but it led to addiction and sometimes deaths.
Synthetic “cocaine copies” were made in laboratories. Amylocaine and later novocaine became the new “caines”. Safer and not addictive, these local anaesthetics allowed surgeons to carry out complex, sometimes lifesaving operations accurately: Awake patients recovered rapidly.
The secret of “caines” is that they block tiny channels in those nerve fibres for a short time. The channels usually allow sodium to move across nerve membranes, sending signals along the nerve. When “caines” plug these pores, there are no signals and so pain disappears. As “caines” are broken down by the body, the anaesthesia wears off. There are no specific antidotes for these local anaesthetics. Again, genetics is important, because anaesthesia lasts a shorter time for some. “Caines” need careful management because they can block signals to muscles, as well as pain nerves. The same system of sodium-based signalling is used to turn our heads, blink our eyes and breathe.
Local anaesthetics are injected around nerves for cosmetic surgeries, biopsies or stitches. In dentistry, they allow a dental surgeon to perform a great variety of procedures, such as fillings or reconstructions, with a cooperative, awake patient. Local anaesthetics have transformed many surgical specialties when used to anaesthetise a region of the body – for instance, a wrist or knee for orthopaedic surgery. Ultrasound systems guiding injections made by the anaesthetist make these methods easier to control.
Large areas of the body can be numbed if local anaesthetic is carefully injected alongside the spinal nerves in the back – an epidural. The most common epidural is used in childbirth. It allows the pelvis and upper legs to be numbed, without troubling the birth process or infant, while allowing partners to be present at the delivery. Should you require an inguinal hernia repair, an epidural is effective. Although you might welcome the idea of a general anaesthetic, a regional block is safer, more comfortable and swifter. A tiny flexible tube may be left in the epidural space to provide anaesthesia for long periods of time. For elderly patients whose lungs might not be as strong as they were, regional blocks are preferable because they do not depress breathing, prevent coughing and may allow patients to remain upright.
Local epidural anaesthesia might be used together with general anaesthetics, for instance, in back surgery. They can assist those with chronic pain, reducing the use of opiates and promoting mobility. Anaesthetics continue to diversify – planned combinations of virtual reality, nerve stimulation and enhanced local anaesthesia can make major operations painless and less fearsome.
Dr. Colin Michie specializes in paediatrics, nutrition, and immunology. Michie has worked in the UK, southern Africa and Gaza as a paediatrician and educator and was the associate Academic Dean for the American University of the Caribbean Medical School in Sint Maarten a few years ago.
