Treatment options for lumbar spinal stenosis and their medicolegal implications 

Lumbar spinal stenosis (LSS) refers to narrowing of the central spinal canal, lateral recesses or intervertebral foramen, leading to compression of the associated neurovascular structures. LSS is characterised by neurogenic claudication, consisting of pain in the buttocks or lower limbs accompanied by neurologic symptoms such as poor balance, numbness or tingling, and muscle weakness. Some patients also experience back pain. Symptoms are generally intermittent and posture-dependent, tending to be exacerbated by walking and relieved by sitting. LSS may be congenital, acquired or both, with most cases arising due to acquired degenerative changes from aging, spinal surgery or infection. Not surprisingly, the prevalence of LSS increases with age, being present to some degree in nearly 80% of patients aged over 65 years, compared to only 12% in those aged below 40 years.

Advanced imaging techniques, improved diagnostic accuracy, and an aging population mean that a diagnosis of LSS is becoming increasingly common. Not only is it one of the most frequently seen conditions in orthopaedic and neurosurgical clinics, but it is also the commonest reason for spinal surgery in patients aged over 65 years. Unfortunately, LSS is associated with chronic pain and disability and can have a significant effect on mobility, function and quality of life. If the nerve root is injured by continuous compression, pain may persist after removal of the cause of the compression.

Initially, treatment for LSS is by non-surgical means. Options include exercise, manipulation techniques, mobilisation, physical therapy, drugs, acupuncture, bracing, education and cognitive behavioural therapy (CBT). These either act directly on pain perception, or they seek to improve mobility and control of movement in the lumbar spine, by either active or passive means. Education and CBT promote healthy behaviours by giving patients information about their condition and how to manage it, thereby improving quality of life. Physical activity has the added benefit of improving overall health, as well as potentially leading to improved function and reduced pain. Non-surgical treatments for LSS are often administered together in a multimodal approach that targets both physical and psychological aspects of the condition. Conservative treatments are not generally associated with major complications.

Epidural steroid injections are indicated in patients with acute radiating pain and has been used for nerve claudication that interferes with normal daily activities that has not responded to other non-surgical treatment options. Many patients report significant symptom alleviation after receiving injections, although the effects tend to only last for a few weeks to months. However, NICE guidance has recommended that epidural steroids are not offered for central spinal canal stenosis.

If symptoms do not respond to conservative treatment, surgery may then be considered. Surgical intervention is seen as the gold standard treatment for LSS and there are two main approaches. In decompression surgery, the amount of space in the spinal canal is increased by removing portions of the posterior spinal laminae, facets, osteophytes, ligaments or synovial cysts. However, removal of these structures may either exacerbate existing instability in the spine or create new areas of instability. Therefore, spinal fusion is sometimes required in addition to the decompression surgery to treat this instability. In the other approach, posterior spinal spacers are inserted into the spine to alter the alignment of the vertebrae without the need for fusion. The goal of this type of surgery is to create enough flexion to open the foramina without disrupting the normal anatomical structures. However, these days spacers appear to be a less commonly chosen technique. Overall, surgeons will carefully consider several factors including age, comorbidities, bone strength and the presence of any instability when selecting a surgical option. 

One major drawback of surgical intervention is the relatively high rate of complications associated with these procedures. Around 17% of patients develop spinal instability and require corrective surgery, usually in the form of fusion. Interspinous spacer insertion also carries a high risk of reoperation, with as many as 27% of patients requiring a second operation within the first year of the initial procedure. Other complications include dural tears, blood loss requiring transfusion, nerve root damage, haematoma, errors of surgery such as misplaced screws, spinous process fracture, infection and readmission to hospital. Pain is another common complication, previously referred to as “post laminectomy syndrome”. Both types of surgery also carry a risk of major medical complications, including cardiopulmonary issues or stroke, and even death, the incidence of which is highest in patients with comorbid disease.

Overall, there is no clear indication whether surgical or conservative treatment is more beneficial, as few studies have directly compared the outcome of the two approaches. Furthermore, the lack of objective measures of function can make it difficult to assess the efficacy of different treatments. The existing evidence indicates that disability scores appear to be comparable between conservative and surgical treatment at 6 months and 1 year post-treatment, although by 2 years decompression surgery gives significantly better results. However, if the outcome measure is pain, no differences are seen between the two treatment approaches, even after 10 years. This may be due to the existence of other underlying spinal conditions. Conversely, one study found that patients treated with interspinous inserts had better outcomes in terms of both symptom severity and physical function, although patients were only followed for up to 1 year.  

However, spacers appear to have fallen out of favour, and if surgery is offered it usually is in the form of decompression. Overall, surgeons carefully consider several factors including age, comorbidities, bone strength and the presence of any instability when selecting a surgical option.  Given the similar outcomes for the two treatment approaches, and the relatively high rate of complications associated with surgery, clinicians should be cautious about recommending surgical intervention for LSS. It is also vital that full disclosure of the risks to patients is made to avoid subsequent litigation.