Multilevel fusion has similar outcomes to single-level fusion but increases operating time

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Yossi Smorgick, William Beaumont Hospital, Royal Oak, USA, and others reported in Spine that multilevel decompression and multilevel fusion does not significantly improve outcomes compared with multilevel decompression and single-level fusion in patients with single-level degenerative spondylolisthesis and multilevel spinal stenosis, but does increase operating time and intraoperative blood loss. 

Smorgick et al wrote that studies have shown that decompression plus fusion is associated with significantly better outcomes than decompression alone in patients with single-level degenerative spondylolisthesis, but added that no studies have evaluated the optimum surgical approach for treating the multilevel spinal stenosis that is often associated with single-level degenerative spondylolisthesis. They commented: “Some surgeons surgically treat these patients with a fusion at only the level of current instability and only decompress the other levels. On the other hand, some clinicians elect to incorporate multilevel fusions as a prophylaxis to adjacent level instability in this clinical scenario.”

According to Smorgick et al, there are potential risks with each approach—decompression only above a fused segment may cause “additional stress on the less stable segment” whereas multilevel fusion requires a longer operation and may increase morbidity. The authors commented that the aim of their study was “to determine the impact of multilevel decompression with single-level fusion compared to multilevel decompression and fusion on patients’ outcomes over time. This analysis represents the first clinical study comparing the different treatment methods for multilevel lumbar spinal stenosis and a single level degenerative spondylolisthesis.”

Using data from the SPORT (Spine patient outcomes research trial), Smorgick et al identified 207 patients with single-level degenerative spondylolisthesis and multilevel stenosis. Of these, 130 received multilevel decompression and single-level fusion while 77 received multilevel decompression and multilevel fusion. They found that both operative time and intraoperative blood loss were significantly higher in the patients who underwent multilevel fusion; they reported: “The average surgical time for the multilevel fusion group was 250 minutes with mean blood loss of 784ml. The average surgical time for the single fusion group was 187 minutes with a mean blood loss of 623ml.”

At the one, two, three, and four years follow-up points, there were no significant differences between the two groups in either primary (eg, bodily pain) or second (eg, spinal stenosis bothersomeness index) outcomes. There was a tendency towards more improvement in the SF-36 physical function score at three years with single-level fusion compared with multilevel fusion, but this difference became insignificant at four years.

Smorgick et al, on the basis of their results, stated: “In an older patient population with more medical comorbidities and frail medical conditions, the added operative time and increased blood loss for multilevel patients may not be warranted, especially if four-year clinical follow-up does not demonstrate added clinical benefit.” 

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