Dynamic stabilization adjacent to single-level fusion: Part II. No clinical benefit for asymptomatic, initially degenerated adjacent segments after 6 years follow-up

Abstract

Progression of degeneration is often described in patients with initially degenerated segment adjacent to fusion (iASD) at the time of surgery. The aim of the present study was to compare dynamic fixation of a clinically asymptomatic iASD, with circumferential lumbar fusion alone. 60 patients with symptomatic degeneration of L5/S1 or L4/L5 (Modic ≥ 2°) and asymptomatic iASD (Modic = 1°, confirmed by discography) were divided into two groups. 30 patients were treated with circumferential single-level fusion (SLF). In dynamic fixation transition (DFT) patients, additional posterior dynamic fixation of iASD was performed. Preoperatively, at 12 months, and at a mean follow-up of 76.4 (60-91) months, radiological (MRI, X-ray) and clinical (ODI, VAS, satisfaction) evaluations assessed fusion, progression of adjacent segment degeneration (PASD), radiologically adverse events, functional outcome, and pain. At final follow-up, two non-fusions were observed in both groups. 6 SLF patients and 1 DFT patient presented a PASD. In two DFT patients, a PASD occurred in the segment superior to the dynamic fixation, and in one DFT patient, a fusion of the dynamically fixated segment was observed. 4 DFT patients presented radiological implant failure. While no differences in clinical scores were observed between groups, improvement from pre-operative conditions was significant (all p < 0.001). Clinical scores were equal in patients with PASD and/or radiologically adverse events. We do not recommend dynamically fixating the adjacent segment in patients with clinically asymptomatic iASD. The lower number of PASD with dynamic fixation was accompanied by a high number of implant failures and a shift of PASD to the superior segment.

Posterior lumbar dynamic stabilization instead of arthrodesis for symptomatic adjacent-segment degenerative stenosis: description of a novel technique

“…However, this study also found a 9.1% incidence of degeneration in the more distant levels. 17,18,23 In a systematic review of literature, Zhou et al found that the incidence of adjacent-segment degeneration was statistically lower in patients treated by dynamic stabilization compared with solid fusion. There was a tendency for a lower incidence of ASD following dynamic stabilization.…”

“…Many studies have reported on an acceleration of the process of degeneration in the spinal segment adjacent to a level of prior arthrodesis that may result in poor clinical outcome and sometimes a need for further surgery. 18 Multiple dynamic stabilization systems are currently available, and all use a variety of motion-preserving technologies ranging from semirigid rods to ball-and-socket joints. 2 The use of dynamic stabilization for the treatment of ASD at the rostral end of an instrumented arthrodesis might therefore reduce further progression of the degenerative process by decreasing hypermobility and stresses in adjacent levels.…”

Does hybrid fixation prevent junctional disease after posterior fusion for degenerative lumbar disorders? A minimum 5-year follow-up study

“…Compared with static fixation, numerous types of dynamic fixators have been developed to preserve the mobility of the transition segments and to reduce the occurrence of the junctional problem [21][22][23]. Among them, the dynamic neutralization system (Dynesys) is one of the commonly used dynamic fixators [12,24]. The Dynesys system consists of titanium alloy pedicle screws, cannulated polycarbonate urethane (PCU) spacers, and tensioned cords made of polyethylene terephthalate (PET).…”

Can posterior dynamic stabilization reduce the risk of adjacent segment deterioration?

“…inclusion criteria (2,3,6,(11)(12)(13)(14)(15)(16)(17)(19)(20)(21)(22)(23)(26)(27)(28)(29)(30)33,34,36,37,(41)(42)(43)(45)(46)(47) (Figure 1). For the possible duplicate studies (31&40,14&23,13&15), only the data from the trial with the longest follow-up were used for estimating the incidence of ASD.…”