Determination of the Distal Fusion Level in the Management of Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis Using Pedicle Screw Instrumentation

Abstract

Study DesignA retrospective study.PurposeTo determine the exact distal fusion level in the management of thoracolumbar/lumbar adolescent idiopathic scoliosis (TL/L AIS) using pedicle screw instrumentation (PSI).Overview of LiteratureThe selection of distal fusion level remains controversial in TL/L AIS.MethodsRadiographic parameters of 66 TL/L AIS patients were analyzed. The patients were grouped according to the distal fusion level; L3 group (fusion to L3, n=58) and L4 group (fusion to L4, n=8). The L3 group was subdivided into L3A (L3 crosses the mid-sacral line with rotation of less than grade II, n=33) and L3B (L3 does not cross the mid-sacral line or rotation is grade II or more, n=25) based on both bending radiographs. All of the patients in the L4 group had the same location and rotation of L3 in bending films as that of patients in the L3B group. An unsatisfactory result was defined as a lowest instrumented vertebral tilt (LIVT) of more than 10° or coronal balance of more than 15 mm.ResultsAmong the 3 groups, there was a significantly lesser correction in the TL/L curve and LIVT in the L3B group. Unsatisfactory results were obtained in 3 patients (9.1%) of the L3A group, in 15 patients (68.2%) of the L3B group, and in 1 patient (12.5%) of the L4 group with a significant difference.ConclusionsIn TL/L AIS treatment with PSI, the curve can be fused to L3 with favorable radiographic outcomes when L3 crosses the mid-sacral line with rotation of less than grade II in bending films. Otherwise, fusion has to be extended to L4.

Selective versus hyperselective posterior fusions in Lenke 5 adolescent idiopathic scoliosis: comparison of radiological and clinical outcomes

“…Moreover, LIV selection in regard to SV and LTV However, longer follow-up might be necessary to observe occurrence of disc degeneration below fusion [32,33]. Moreover, neither selective nor hyperselective fusions significantly affected postoperative LL, which is in accordance with previous literature [14]. However, five patients from the selective group had lumbar hypolordosis at follow-up (although these normative values were obtained from adult patients).…”

“…Recently, some surgeons have tended to reduce their fusion length in posterior procedures as well (hyperselective fusion), using the criteria initially described for anterior surgery, because they strongly believed in the 3D correction potential of pedicle screws and were concerned about the future risk of adjacent degeneration [10,14]. The aim of this study was, therefore, to compare the clinical and radiological outcomes of selective and hyperselective fusions in Lenke 5 AIS operated via posterior approach.…”

Criteria for Ending the Distal Fusion at the L3 Vertebra vs. L4 in Surgical Treatment of Adolescent Idiopathic Scoliosis Patients with Lenke Type 3C, 5C, and 6C Curves: Results After Ten Years of Follow-up

“…With the use of pedicle screws, the planning for the level of fusion was begun to be performed using flexibility radiographs such as supine bending or fulcrum bending [ 2 , 3 , 7 , 8 , 22 - 24 ]. According to the use of bending radiographs in fusion site selection, the fusion should be ended over the neutralized disc gap in the distal on bending radiographs.…”

“…Selection of the L3 or L4 vertebra as the LIV in thoracolumbar/lumbar curvatures has been a matter of research in several studies. Kim et al reported successful results with ending the fusion at the L3 level in patients where the midsacral line passes through the L3 vertebra on concave bending radiographs and the rotation falls below Nash and Moe Grade 2 on convex bending radiographs [ 8 ]. Wang et al specified a translation of less than 28 mm and a tilt of less than 25 degrees as the general criteria for LIV selection in patients with Lenke Type 5C scoliosis [ 25 ].…”

“…The most critical decision at this point is determining the level of the spinal fusion. Despite the abundant publications on the surgical treatment of idiopathic scoliosis, few have investigated the selection of the fusion site or how the decision is made in structural lumbar curves [ 1 - 8 ].…”