Surgical interventions for lumbar disc prolapseRob Mihov, ST3 group ‘Seychelles’
Prolapsed lumbar disk accounts for less than 5% of all low back problems, but most common cause for sciatica
90% of sciatica settle with non surgical management
Many lumbar disc herniations cause no significant symptoms. (In studies of asymptomatic individuals who have never experienced lumbar-related symptoms, 30% have been reported to have major abnormality on magnetic resonance imaging, Boden 1990).
Most common surgical interventions:
discectomy – surgical removal of part of the disc
microdiscectomy – discectomy with the use of magnification
chemonucleolysis(not common anymore) – injection of an enzyme into bulging spinal disc in an effort to reduce the size of the disc
The mainstay of treatment of patients with symptomatic disc herniations is accepted to be nonoperative. (Orthopedic Clinics North America, vol.41,Apr 2010)
Absolute indications for surgery include altered bladder function and progressivemuscle weakness, but these are rare.
Usual indication: to provide more rapid relief of pain and disability in the minority of patients whose recovery is unacceptably slow. Overall, surgical discectomy for carefully selected patientswith sciatica due to a prolapsed lumbar disc appears to provide faster relief from the acute attack than non-surgical management.
The primary rationale of disc surgery is to relieve nerve root irritation or compression, but the results should be balanced against the likely natural history.
Despite clinical importance of knowing whether surgery is beneficial, only four trials up to 2007 (Cochrane library) directly compared discectomy with non-surgical procedures. These provide suggestive rather than conclusive results.
Trials showed that discectomy produced better outcomes than chemonucleolysis, which in turn was better than placebo. For various reasons including concerns about safety chemonucleolysis is not commonly used today to treat prolapsed disc.(Gibson, 2007, Cochrane library)
Weber randomized controlled study (RCT)1983 – controlled prospective study with 10 years follow up – 280 enrolled patients, 126 randomized to either surgery of physical therapy. The groupd randomized to surgery had statistically better outcomes after 1 year. After 4 years however, After 4 years, however, although the surgery outcomes were still better, this difference was no longer statistically significant.
Buttermann(2004 )conducted a prospective, randomized study comparing epidural steroid injection (ESI)with discectomy for treatment of lumbar disc herniation. One hundred patients who had failed non invasive therapy for 6 weeks were randomly assigned to receive ESI or discectomy. The investigators stated that ESI was not as effective as surgery in reducing symptoms in those with large herniations. Very limited data are available from a trial comparing microdiscectomy plus isometric muscle training with plain muscle training and this trial is labelled ’ongoing’.
Osterman and colleagues (2003) conducted a prospective, randomized study comparing physical therapy with discectomy for treatment of lumber disc herniation. Fifty-six patients who had radiating back pain below the knee for 6 to 12 weeks were randomized to receive either isometric physical therapy or discectomy. Patients were followed for 2 years and at final follow-up the study found no clinically significant difference between the groups in terms of leg pain intensity and other secondary outcomes. These investigators proposed discectomy providedonly some short-term benefit.
Another study by Peul and colleagues(2007)was a prospective, randomized study comparing nonsurgical treatment with discectomy for the treatment of lumbar disc herniation. 280 subjects were followed for a year and the investigators found that the 2 groups had similar outcomes at 1 year, but those who underwent surgery had faster rates of recovery andself-perceived pain.
Authors’conclusion(2008 The Cochrane collaboration, Surgical Intervention for lumbar disc prolapse):There is considerable evidence that surgical discectomy provides effective clinical relief for carefully selected patients with sciatica due to lumbar disc prolapse that fails to resolve with conservative management. It provides faster relief from the acute attack of sciatica, although any positive or negative effects on the long-term natural history of the underlying disc disease are unclear. There is still a lack of scientific evidence on the optimal timing of surgery. The choice of micro- or standard discectomy at present probably depends more on the training and expertise of the surgeon, and theresources available, than on scientific evidence of efficacy. However, it is worth noting that some form of magnification is now used almost universally in major spinal surgical units to facilitate vision.
All the RCTs of lumbar disc herniation treatment performed over the last 2 decades consistently had high crossover rates and were not able to definitively answer important questions about patient care.These recurring issues raise the question if it is possible to conduct a valid and quality RCT of treatment outcomes for lumbar disc herniation.
References:
1. Surgical interventions for lumbar disc prolapse, Gibson JNA, Waddell G, The Cochrane library 2008, issue 4
2.Contemporary management of symptomatic lumbar disc herniations Kolawole, Jegede, Anthony Ndu, Jonathan Grauer, Orthopedic Clinics North America, Apr 2010