From the Journals

Microdiscectomy lessens pain intensity after persistent sciatica



Microdiscectomy could significantly reduce pain intensity at 6 months in people with chronic sciatica caused by lumbar disc herniation, a randomized controlled trial has found.

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Researchers reported the outcomes of a single-center trial in the New England Journal of Medicine in which 128 patients with chronic sciatica resulting from lumbar disc herniation were randomized either to microdiscectomy or 6 months of standardized nonoperative care, followed by surgery if required.

Chris S. Bailey, MD, of the Schulich School of Medicine and Dentistry at Western University in Toronto, Ontario, and coauthors wrote that, while the majority of patients with sciatica from acute herniation of the lumbar disc improve with conservative care, there is little study comparing surgery with conservative care in patients whose symptoms have lasted longer than 3 months.

In this study, all patients had experienced unilateral radiculopathy for 4-12 months. Those randomized to surgery were operated on a median of 3.1 weeks after enrollment, while those randomized to nonsurgical treatment received education on exercise, functioning, and the use of oral analgesics, as well as active physiotherapy and epidural glucocorticoid injections if needed.

At 6 months, the surgical group showed significantly lower visual analog scale scores for leg-pain intensity, compared with the nonsurgical group (2.8 vs. 5.2; 95% confidence interval, 1.4-3.4; P < .001) and the difference persisted at 1 year (2.6 vs. 4.7).

In an editorial accompanying the study, Andrew J. Schoenfeld, MD, and James D. Kang, MD, of the department of orthopedic surgery at Brigham and Women’s Hospital and Harvard Medical School, both in Boston, described the results in this group of patients with persistent sciatica as “encouraging,” and suggested the improvement may be because the surgery achieves more rapid decompression of the compressed nerve.

“Patients in the current trial who were assigned to undergo surgery received the intervention relatively quickly, at a median of 3 weeks, and it is reasonable to conclude that expeditious removal of the nerve compression minimized the potential for long-term persistence of pain,” they wrote.

Among the 64 patients who were randomized to nonsurgical treatment, 22 (34%) crossed over to undergo surgery at a median of 11 months after enrollment in the study. These patients tended to be younger at baseline, and less likely to have an asymmetrical decrease in reflexes.

The intention-to-treat analysis found a similar rate of surgical adverse events in the group initially randomized to surgery and the group who crossed over to have surgery (6% vs. 8%). Two patients in the surgical group and one in the crossover group experienced superficial wound infections, while two patients in the crossover group and one in the surgical group experienced new-onset postoperative neuropathic pain. Two patients in the surgical group also had a recurrence of their herniation; one underwent further surgery for it 250 days after the initial procedure, and the other did not.

The secondary outcomes of the study were disability score, physical health, mental health, back pain intensity, satisfaction with treatment, and employment status. All these showed differences that favored the surgical intervention, but “the absence of a prespecified plan for adjustment for multiple comparisons does not allow for clinical inferences from secondary outcomes.”

The authors noted that some previous randomized trials have shown that surgery was better than conservative care among patients with lumbar disc herniation for the first 6 months, but those trials largely focused on patients who had had symptoms for less than 4 months at the time of the intervention. The results of these trials had also been mixed; some trials in patients with shorter duration of symptoms found little or no benefit of surgery over conservative care.

“The decision about whether to recommend discectomy or nonsurgical treatment in this population is controversial because a longer duration of symptoms has been correlated with a poorer outcome associated with lumbar discectomy in some studies,” they wrote. “However, patients may prefer to avoid surgery if they think that nonsurgical treatment could be successful or if they anticipate a risk from surgery.”

There was the risk for selection bias in the study, the authors said, because both surgeons and patients might have been less inclined to go with nonsurgical care in cases of more severe sciatic pain. However they said patients did not have the option of choosing to have surgery at the center outside the trial, which should have minimized that risk.

The authors of the editorial noted that while the study limited itself to patients who had had symptoms for 4-12 months, it didn’t account for other clinical factors that might impact the outcome of discectomy, such as the size of disc herniation or extent of nerve compression.

They also pointed out that questions still remained about which patients were more likely to benefit from immediate surgical intervention and how long nonsurgical care should be trialed before recommending surgery.

The study was supported by a grant from the Physicians’ Services Incorporated Foundation. None of the study authors reported conflicts of interest. Dr. Kang reported grants from Pfizer, personal fees from DePuy (Johnson & Johnson), nonfinancial support from Stryker, owning stock in ALung and Cardiorobotics, and serving on a scientific advisory board for OnPoint Surgical, outside the submitted work. Dr. Schoenfeld reported grants from the National Institute for Arthritis and Musculoskeletal and Skin Diseases, the Orthopaedic Research and Education Foundation, and the U.S. Department of Defense, outside the submitted work.

SOURCE: Bailey C et al. N Engl J Med. 2020;382:1093-102.

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