What are sciatica and brachalgia?
The terms sciatica and brachalgia are used to describe nerve pain in the leg and in the arm respectively. Anyone who has ever had nerve pain will tell you that it is like no other pain they have ever had before. They tend to use very characteristic words to describe it, like “burning”, “gnawing”, “aching”, “shooting”, “electric shock.” Nerve pain does not respond very well to normal painkillers that you can get from a pharmacy, and even many doctors often find it hard to believe that it is painful as patients tell them it is. But it is usually excruciatingly painful, and patients can often find no respite from it even if they are taking large doses of very strong painkillers. Many patients can’t find a comfortable position during the day or night and they quickly get very tired.
Sciatica is nothing to do with the sciatic nerve, which is the large nerve formed by a combination of smaller nerves which leave from the lumbar spine and the section of spine below that called the sacral spine. These smaller nerves join together outside the spine deep inside the pelvis to form the sciatic nerve. The sciatic nerve runs deep in the buttock where it starts to give off branches as it travels down the back of the thigh. It controls all the muscles in the back of the thigh and all the muscles below the knee. It also carries all the sensory signals from these regions back to the spinal cord on their way to the brain.
The pain from sciatica is normally felt in a line starting as high as the low back, but more often in the buttock. It then travels down the leg, most often at the back or outside of the thigh and lower leg, but sometimes in the front of the thigh and over the knee, depending on which lumbar spinal nerve is affected. It often causes symptoms in the outside of the ankle or sole of the foot.
Brachalgia is the analogy of sciatica affecting spinal nerves from the neck and pain is felt in the shoulder, arms, and hands. It can start as high as the neck and sometimes the back of the head, and many patients have severe pain in the region of the shoulder blade.
What causes them?
Both sciatica and brachalgia are due to compression or irritation of spinal nerve roots as they are leaving the spinal canal.
The main causes are:
- Herniated intervertebral disc
- Degenerative disc disease
- Osteophyte formation
- Facet joint hypertrophy
- Spinal stenosis
- Spinal cancer
How can they be treated?
The treatment depends on the cause, so we need to find out the cause first of all. This starts with a full medical history and clinical examination, and then moves onto appropriate investigations, which usually involves a X-rays, MRI, or CT. Sometimes neurophysiology studies will also be done.
Manipulation can sometimes make sciatica and brachalgia worse and should generally be avoided until the patient has been fully assessed.
Sciatica and brachalgia occasionally go away on their own without any treatment but more often than not they don't, and patients can have a miserable time living with it. Even strong painkillers such as Morphine often don't help very much and patients frequently find that suffering side effects of medication while living with nerve pain is worse than suffering the nerve pain on its own. Specialist nerve pain medication such as Gabapentin or Pregabalin can sometimes help, but these are generally more effective for pain coming from small nerves rather than relatively large spinal nerve roots.
Diazepam can be effective and patients often find that it is more helpful than any analgesics, but this shouldn't be used for more than a few days.
If the pain from sciatica or brachalgia can't be controlled quickly by medication the next step for most patients is for them to have some steroids injected around the affected nerve root. This has to be done very accurately, the injections being guided by continuous x-ray or by CT scanning.
This is frequently effective at significantly alleviating pain, sometimes almost instantly but it can take a few days. It may need to be repeated on up to two further occasions during the acute phase of the condition but most patients can avoid surgery by having these treatments.
If the pain cannot be controlled by analgesics or by image guided spinal steroid injections then the next step is to consider surgery. The main indications for surgery to treat sciatica or brachalgia are the following:
- Inability to adequately control pain by analgesics and image guided percutaneous treatments
- Progressive muscle weakness or numbness due to nerve compromise
- Problems with bladder or bowel control in the presence of a known lumbar disc herniation.
What are the risks and outcomes of the various treatments?
Most patients get better in a few weeks with simple conservative management consisting of analgesia and physical therapy. These few weeks can seem like a lifetime for patients whose pain cannot be adequately controlled. The risks of conservative management are less than those of any interventional treatment, but there can be a risk attached to putting off these treatments too long.
If bladder or bowel weakness occur this is a surgical emergency called “Cauda Equina Syndrome.” If the spine is not surgically decompressed within hours the patient can be permanently paralysed.
With prolonged nerve compression and progressive weakness in the arm or leg muscle strength may take many months to recover even after surgery and may not fully recover at all. Similarly if numbness develops the skin may not return to normal sensation.
It is vital therefore that if you develop sciatica or brachalgia you are evaluated and cared for someone who will know when to recommend that you have surgery.
What about the risks of surgery? While there are risks attached to surgery they should be weighed against the benefits, and against the risks of not operating. There are the general risks associated with all surgical procedures such as bleeding, infection, and general medical problems, but there are also risks associated with the nature of the surgery being undertaken. Obviously the spinal cord and nerve roots are very close to the site of surgery and these can, in rare circumstances, become damaged. Other structures nearby can also be damaged in rare instances. There is a small risk that the symptoms may be worse after surgery as the result of a complication. These risks are small though, with a serious surgical complication rate of typically less than 5% in the best centres.
The decision of whether to proceed to surgery, if so when, what sort of surgery to have, and by whom, should be made in close consultation with your spine specialist. It should be remembered though that the majority of patients with sciatica or brachalgia do not need surgery. These patients can be managed by a combination of analgesia, image guided percutaneous treatments, and carefully supervised physical therapy.
Managing sciatica and brachalgia is our main specialty interest.