Spinal Claudication / Lumbar Canal Stenosis
Spinal claudication is a term which describes walking difficulties because of pressure on the nerves in the lumbar canal. This is usually caused by wear and tear resulting in narrowing of the spinal canal (spinal canal stenosis). The canal can be narrowed by a slipped disc in the front, overgrowth (hypertrophy) of the facet joints on the sides and overgrowth of the yellow ligament which runs in the back of the canal (ligament flavum hypertrophy). In most cases it is a combination of these. The condition affects patients over the age of 60 in most cases but can develop at an earlier age. Sometimes, it can be the result of a slippage of the spine (spondylolisthesis) or tumours (very rare).
The classical symptoms are numbness or heaviness of the legs when standing or walking for a period of time. This can be associated with pain in the back or down the legs. In most cases it starts slowly and can progress over months or years. If the patients stops and rests the symptoms improve. Bending forward increase the diameter of the spinal canal and can ease the compression. This is why patients with lumbar canal stenosis often find it easier to walk with a trolley (when shopping).
Narrowing of the arteries supplying the legs (vascular claudication) may produce very similar symptoms. Patients with vascular claudication often develop symptoms when lying in bed (cramps). Very few patients have both conditions which can cause a diagnostic dilemma.
Cauda equina syndrome is a very uncommon complication because the disease progress is very slow. Spinal claudication often limits the overall mobility of patients and can make patients virtually housebound.
Taking an accurate history is important to obtain information about the progression of the symptoms and how much it affects day-to-day life. As many patients are elderly, it is important to establish the presence of other medical problems and risk factors for vascular claudication (smoking, diabetes, high blood pressure) which is the most important clinical differential diagnosis. Clinical examination is important but neurological examination is essentially normal in most cases apart from sluggish or absent ankle and knee jerks. Foot pulses should always be examined to exclude the presence of vascular stenosis.
To establish the diagnosis, MRI scan is the investigation of choice unless there are contra-indications. In this case a CT or myelogram is indicated.
Treatment and Outlook
In many mild cases, spinal claudication can be treated without surgery. Physiotherapy and reduction in weight in obese patients can improve or stabilise symptoms. Epidural injections can significantly improve the walking distance and leg pain for several months but is no longer paid for by the NHS. Painkillers usually do not work in most patients.
Surgery improves the walking distance and leg pain in the majority of patients (70-80%). Even patients in their 80s or even 90s can respond quiet dramatically to surgical decompression and become more independent and mobile. It does not, however, cure the underlying problem of wear and tear and symptoms can deteriorate some years later again.
The operation of choice is a laminectomy or intersegmental decompression. Lately, so-called interspinous spacers (for example X-stop, Wallis ligaments, In-space and others) have been developed which can also improve the stenosis by stretching the ligaments and opening the channels where the nerves leave the spine. There is no evidence that these devices are better than conventional surgery but may have some advantages in operating time. They are significantly more expansive.