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Pedicle screws for AIS confer less complications than hybrid instrumentation

Tristan Manalac
21 Aug 2017

Pedicle screw constructs for adolescent idiopathic scoliosis (AIS) result in better coronal correction and less overall complications compared with hybrid instrumentation but provide less restoration of thoracic kyphosis, according to a new meta-analysis.

“As regards the pedicle screw construct, the most common reasons for reoperation are malposition, deep infection, pseudarthrosis and prominent implant,” researchers said.

Pooled data from 10 studies (pedicle screw n=1,068; hybrid instrumentation n=963) showed that rates of complications were significantly lower in patients who received pedicle screws than in those who received hybrid instrumentation (6.46 vs 11.11 percent; p<0.001; odds ratio [OR], 0.61; 0.42 to 0.87; p=0.007). [Medicine 2017; 96:e7337]

Moreover, while the rate of screw malposition in the pedicle screw group was almost twice that in the hybrid instrumentation group (1.87 vs 0.93 percent), the rate of dislodged instrumentation (0.00 vs 0.93 percent, p=0.005) was significantly lower in the pedicle screw group.

Rates of pseudarthrosis (0.37 vs 1.35 percent; p=0.016) and perioperative complications (1.97 vs 3.95 percent; p=0.008) were also significantly lower in the pedicle screw group.

“Compared with hooks, more stable and maintained fixation of pedicle screws was reported, which effectively reduced incidence of pseudarthrosis and instrumentation dislodgement,” explained researchers. [Int Orthop 1994;18:341-346; Eur Spine J 2002;11:336-343]

“The most common perioperative complications were respiratory complications, excessive blood loss and urinary tract infection,” they added.

Reoperation was examined in six studies (pedicle screws n=969; hybrid instrumentation n=663). Patients who received pedicle screws had significantly reduced rates of reoperation (3.30 vs 7.24 percent; p<0.001; OR, 0.37; 0.22 to 0.62; p=0.0001).

Among the reasons for reoperation, the incidences of pseudoarthrosis (0.41 vs 1.81 percent; p=0.005), dislodged instrumentation (0.00 vs 1.06 percent; p=0.005) and deep infection (0.93 vs 2.41 percent; p=0.016) were significantly lower in the pedicle screw than in the hybrid instrumentation group.

“The most common reasons of reoperations were deep infection, malposition, pseudarthrosis, prominent implant and dislodged instrumentation,” according to researchers, adding that coronal correction was significantly better in pedicle screws.

The meta-analysis included controlled trials of pedicle screws or hybrid instrumentation for AIS. Only those that reported complications or radiographic outcomes were included. Exclusion criteria were neuromuscular scoliosis patients and no final follow-up.

The Newcastle-Ottawa Scale was used to evaluate methodological quality and risk of bias of the nonrandomized controlled studies. A funnel plot was used to determine publication bias.

One important limitation of the meta-analysis is the inclusion of mostly only retrospective studies resulting in loss of important evidence. The researchers recommended that future randomized controlled trials be performed to validate the present findings.

Additionally, “complication is a broad concept that includes many aspects, such as in-hospital complication, long-term complication and radiographic complication. The accuracy of complication rates was impacted by the various methodologies to report complication,” they said.

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Most Read Articles
07 Mar 2018
The use of trabecular bone score (TBS) may be helpful in evaluating osteoporosis in ankylosing spondylitis (AS), as it is associated with the erythrocyte sedimentation rate (ESR) and severity of sacroiliitis in young male patients with AS, suggests a recent study.