Topping-off technique for stabilization of lumbar degenerative instabilities in 322 patients

J Neurosurg Spine 32:366–372, 2020

Semi-rigid instrumentation (SRI) was introduced to take advantage of the concept of load sharing in surgery for spinal stabilization. The authors investigated a topping-off technique in which interbody fusion is not performed in the uppermost motion segment, thus creating a smooth transition from stabilized to free motion segments. SRI using the topping-off technique also reduces the motion of the adjacent segments, which may reduce the risk of adjacent segment disease (ASD), a frequently observed sequela of instrumentation and fusion, but this technique may also increase the possibility of screw loosening (SL). In the present study the authors aimed to systematically evaluate reoperation rates, clinical outcomes, and potential risk factors and incidences of ASD and SL for this novel approach.

METHODS The authors collected data for the first 322 patients enrolled at their institution from 2009 to 2015 who underwent surgery performed using the topping-off technique. Reoperation rates, patient satisfaction, and other outcome measures were evaluated. All patients underwent pedicle screw–based semi-rigid stabilization of the lumbar spine with a polyetheretherketone (PEEK) rod system.

RESULTS Implantation of PEEK rods during revision surgery was performed in 59.9% of patients. A median of 3 motion segments (range 1–5 segments) were included and a median of 2 motion segments (range 0–4 segments) were fused. A total of 89.4% of patients underwent fusion, 73.3% by transforaminal lumbar interbody fusion (TLIF), 18.4% by anterior lumbar interbody fusion (ALIF), 3.1% by extreme lateral interbody fusion (XLIF), 0.3% by oblique lumbar interbody fusion (OLIF), and 4.9% by combined approaches in the same surgery. Combined radicular and lumbar pain according to a visual analog scale was reduced from 7.9 ± 1.0 to 4.0 ± 3.1, with 56.2% of patients indicating benefit from surgery. After maximum follow-up (4.3 ± 1.8 years), the reoperation rate was 16.4%.

CONCLUSIONS The PEEK rod concept including the topping-off principle seems safe, with at least average patient satisfaction in this patient group. Considering the low rate of first-tier surgeries, the presented results seem at least comparable to those of most other series. Follow-up studies are needed to determine long-term outcomes, particularly with respect to ASD, which might be reduced by the presented approach.

Complications associated with the Dynesys dynamic stabilization system

dynesys

Neurosurg Focus 40 (1):E2, 2016

The Dynesys dynamic stabilization system is an alternative to rigid instrumentation and fusion for the treatment of lumbar degenerative disease. Although many outcomes studies have shown good results, currently lacking is a comprehensive report on complications associated with this system, especially in terms of how it compares with reported complication rates of fusion.

For the present study, the authors reviewed the literature to find all studies involving the Dynesys dynamic stabilization system that reported complications or adverse events. Twenty-one studies were included for a total of 1166 patients with a mean age of 55.5 years (range 39–71 years) and a mean follow-up period of 33.7 months (range 12.0–81.6 months). Analysis of these studies demonstrated a surgical-site infection rate of 4.3%, pedicle screw loosening rate of 11.7%, pedicle screw fracture rate of 1.6%, and adjacent-segment disease (ASD) rate of 7.0%. Of studies reporting revision surgeries, 11.3% of patients underwent a reoperation. Of patients who developed ASD, 40.6% underwent a reoperation for treatment.

The Dynesys dynamic stabilization system appears to have a fairly similar complication-rate profile compared with published literature on lumbar fusion, and is associated with a slightly lower incidence of ASD.