Elsevier

World Neurosurgery

Volume 110, February 2018, Pages e258-e265
World Neurosurgery

Original Article
Surgical Outcomes After Segmental Limited Surgery for Adjacent Segment Disease: The Consequences of Makeshift Surgery

https://doi.org/10.1016/j.wneu.2017.10.150Get rights and content

Background

To minimize surgical morbidity, surgeons may opt to perform segmental limited surgery instead of fusion extension for adjacent segment disease (ASD) after lumbar fusion surgery. This study evaluated clinical outcomes from segmental limited surgery without fusion extension for ASD and assessed which clinical factors were associated with reoperation after segmental limited surgery.

Methods

Medical data of 50 patients who underwent segmental limited surgery for ASD after lumbar fusion surgery between 2005 and 2015 were reviewed. Demographic data, ASD type, preoperative disc and facet degeneration, ASD location, and surgical summary were collected. The primary outcome was reoperation rate at 24 months after surgery.

Results

Of patients, 28 (56%) experienced recurrent radiculopathy (visual analog scale score ≥4). Revision surgery was performed in 22 patients (44%). Reoperation was performed more frequently in multilevel fusion first-surgery cases (15/23; 65.2%) than single-level fusion first-surgery cases (7/27; 25.9%; P = 0.005). The lowermost mobile segment group had a lower reoperation-free survival rate than the other group (hazard ratio = 9.85, 95% confidence interval 1.32–73.54, P = 0.01 [log-rank]). The 2-year reoperation-free survival rate for the lowermost mobile segment group was 31.5%, whereas the rate for the other group was 83.3%.

Conclusions

Segmental limited surgery as a treatment for ASD after lumbar fusion surgery is likely to fail frequently and result in a high rate of recurrent radiculopathy and revision surgery. Fusion extension surgery is especially recommended for ASD at the lowermost mobile segment owing to the high failure rate.

Introduction

Lumbar fusion surgery is a standard surgical technique to treat degenerative spinal disease, including herniated nucleus pulposus, spinal stenosis, spondylolisthesis, and instability.1 Circumferential or 360° fusion, which involves interbody fusion with pedicle screw fixation, has been used to restore segmental stability and spinal balance. This surgical technique has a superior fusion rate compared with posterolateral fusion.2 As a result, circumferential fusion surgery is regarded as a valuable treatment option for degenerative spinal disease.

However, lumbar fusion surgery also causes several long-term symptomatic complications, including adjacent segment disease (ASD). ASD originates from the basic concept of spinal fusion, in which well-fused spinal segments lose their segmental mobility, and consequently the biomechanical load of adjacent segments increases to maintain the alignment of the whole lumbar spine during movement.3, 4 The standard surgical treatment for symptomatic lumbar ASD has not yet been established. At the present time, decompression of neural elements with additional fusion extension is the preferred method for treating lumbar ASD.5 However, extended fusion may yield further degeneration in newly created adjacent segments,6 and additional fusion requires longer surgery time and increased blood loss, which are associated with postoperative complications. Moreover, if patients have significant medical problems, they are not eligible to undergo fusion extension. To minimize surgical morbidity, surgeons may select segmental limited surgery, such as decompression only or stand-alone interbody fusion without rod extension. Little is known about the natural course of segmental limited surgery for ASD after lumbar fusion surgery. Therefore, we evaluated the clinical outcomes from segmental limited surgery without fusion extension for ASD, and we assessed which clinical factors were associated with poor clinical outcomes after segmental limited surgery without fusion extension.

Section snippets

Study Design

We defined segmental limited surgery to distinguish these surgeries from full revisions of previously fused segments and extended fusion to index segments. In segmental limited surgery, we opened the index segment and performed decompression, discectomy, or stand-alone cage insertion on the specified segment. In cases of fusion extension, we opened whole segments, such as the index segment and prior fused segment. The surgeon's reasons for performing segmental limited surgery included shorter

Demographic and Clinical Data

Our sample consisted of 27 men and 23 women. Mean patient age at the time of surgery for ASD was 62.6 years ± 8.9. Patients were divided into 2 groups according to the segment that underwent initial fusion (single level vs. multilevel). The mean interval between the first fusion surgery and the second surgery was 100.3 months (range, 3–645 months). Specifically, the mean interval of central canal stenosis was 98.14 months (range, 10–267 months). Patients were categorized according to ASD type

Discussion

This study demonstrates that temporary remedies for ASD have a high likelihood of failure. Segmental limited surgery for ASD after lumbar fusion surgery was associated with poor prognosis. Of patients, >50% (28 of 50) had to undergo repeat radiculopathy, and 78.6% required revision surgery later in the follow-up period. Patients with risk factors, including prior multilevel fusion, foraminal stenosis, unilateral foraminotomy, or stand-alone cage, had a higher reoperation rate during the

Conclusions

Segmental limited surgery to treat ASD following lumbar fusion surgery is likely to fail owing to high rates of recurrent radiculopathy and revision surgery. LMS was the most accurate predictor of reoperation-free survival after segmental limited surgery. Multilevel prior fusion and segmental limited surgery owing to foraminal stenosis were associated with higher reoperation rates. In particular, fusion extension should be considered instead of segmental limited surgery when the above-mentioned

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    Conventionally, a long incision is needed to expose both the ASD levels and the prior fusion levels in RS. This procedure requires a longer surgical time and leads to a larger volume of blood loss, more complications, and more medical expenses.30,31 The volume of blood lost during RS has been reported to be 11.61% larger than that of primary surgery.32

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Conflict of interest statement: This work was supported by INHA University Hospital Research Grant.

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