Outcomes Similar With Ventral vs Dorsal Approach to CSM Surgery

Nancy A. Melville

July 06, 2020

In the surgical treatment of multilevel cervical spondylotic myelopathy (CSM), no significant differences in outcomes were found for ventral and dorsal approaches in a randomized trial.

However, dorsal laminoplasty was associated with improved outcomes with regard to health-related quality of life. In addition, there were fewer complications, and hospital charges were lower compared with either ventral or dorsal fusion.

"The Cervical Spondylotic Myelopathy-Surgical Study (CSM-S) is the first randomized controlled trial comparing ventral and dorsal surgery for CSM, and no differences were found," said Zoher Ghogawala, MD, chairman of the Department of Neurosurgery, Beth Israel Lahey Hospital and Medical Center, and professor of neurosurgery, Tufts University School of Medicine, in Boston, Massachusetts.

"Laminoplasty is associated with superior health-related quality of life, fewer complications, and less outpatient health resource utilization at 1 year," he said.

The findings were presented at the virtual American Association of Neurological Surgeons (AANS) 2020 Annual Meeting.

CSM is among the most common conditions that neurosurgeons treat. It accounts for an estimated 40,000 surgical cases per year in the United States.

Complication rates are relatively high, at 15% to 18%, and hospital charges exceed $2 billion per year, yet no optimal surgical approach has been established, the authors note.

In the CSM-S trial, to compare outcomes of the different surgical options, Ghogawala and colleagues enrolled 163 patients with CSM that involved two or more levels of cervical stenosis.

The patients' baseline characteristics were comparable; 49% of the patients were male. In a methodology meant to establish clinical equipoise, each patient in the trial was reviewed by 15 expert cervical spine surgeons. Equipoise was determined to have been met if more than 50% of the surgeons voted for randomization of ventral vs dorsal surgery and if fewer than 80% of the experts voted for the same approach of ventral fusion vs dorsal fusion vs laminoplasty.

The patients were randomly assigned to undergo ventral or dorsal surgery in a 2:3 ratio to allow comparison in the dorsal subgroups of dorsal fusion, laminectomy, and laminoplasty.

For the primary outcome of 1-year change in Short Form–36 (SF-36) Physical Component Summary (PCS) score, there was no significant difference in ventral (5.7) and dorsal (6.3) surgeries (P = .69).

However, in an additional planned analysis, patients who underwent dorsal laminoplasty (n = 28) had significantly greater improvements in SF-36 PCS compared with those who underwent dorsal fusion (n = 69) and ventral fusion (n = 66; both P = .04).

Patients who underwent dorsal laminoplasty also had significantly fewer overall complications (10.7%) compared to those who underwent ventral fusion (42.4%) and dorsal fusion (27.5%; P = .007).

There were no significant differences between the groups with respect to major complications, with rates of about 16% across the surgeries.

Hospital charges with dorsal laminoplasty were approximately half of those with the fusion surgeries. The average cost was $55,332 for laminoplasty, compared to $90,687 for ventral fusion and $111,705 for dorsal fusion (P < .05).

In addition, rates of opioid use were lower among the patients who underwent dorsal laminoplasty (39% vs 45% for ventral fusion and 65% for dorsal fusion; P = .02).

A notable limitation of the study was that the laminoplasties in the study were performed by only five surgeons, which Ghogawala said reflects a lack of training in the United States for the procedure.

"The key limitation is that many surgeons in the United States are not trained on how to do a laminoplasty, so the results might not immediately translate into better outcomes," he told Medscape Medical News.

The cervical laminoplasty procedure, which was developed and first described in Japan, is generally more commonly used in Asia and Europe than in the United States, where ventral or dorsal fusion is favored.

"There is considerable debate on which operation is best for treating patients with CSM," Ghogawala said.

He noted that the findings suggest that "more surgeons should be trained to do laminoplasty, and more studies should be done to identify the ideal patients for laminoplasty.

"Laminoplasty, which is underutilized in the US, has potentially superior outcomes compared with alternatives and should be considered more for patients with CSM in this country."

Commenting on the research, Vincent C. Traynelis, MD, director of the Neurosurgery Spine Fellowship Program and professor in the Department of Neurosurgery, Rush Medical College, in Chicago, Illinois, noted that the unique methodology of establishing a clinical equipoise population is an important strength of the study.

"The study is a very important work due to the unique methodology used, which could be employed in future studies, and also for the focus it places on the potential value of laminoplasty," said Traynelis, who was a discussant for the study.

Although study methodologies can result in significant differences in cost estimates, "it is clear that laminoplasty is roughly 50% the cost of a dorsal fusion," Traynelis added.

The study received funding from the National Institutes of Health and the Patient-Centered Outcomes Research Institute. Ghogawala owns intellectual property and shares in Nidus Inc, which is not related to the CMS trial. Traynelis has relationships with Medtronic and NuVasive.

American Association of Neurological Surgeons (AANS) 2020 Annual Meeting. Abstract 415.

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