Operative management of high-grade dysplastic L5 spondylolisthesis with the use of external transpedicular fixation: advantages and drawbacks

Management of High-Grade Dysplastic Spondylolisthesis

The Meyerding classification grades the degree of slippage in the sagittal plane on lateral standing neutral imaging: 0% to 25% Grade I, 25% to 50% Grade II, 50% to 75% Grade III, 75% to 100% Grade IV, and greater than 100% Grade V (Spondyloptosis). Grades I and II are considered low-grade and Grades III-V are considered high-grade. There are several etiologies of spondylolisthesis. A classification system of the most common causes: Type I - Dysplastic, Type II - Isthmic (including subtypes: A - Lytic, B - Elongation, and C - Acute fracture), Type III - Degenerative, Type IV - Traumatic, Type V - Pathologic, and Type VI - Iatrogenic. Dysplastic spondylolisthesis is a type of spondylolisthesis that occurs at L5-S1 when dysplastic lumbosacral anatomy is present, and is associated with high-grade slip and spina bifida occulta.

Surgical correction of severe spinal deformities using a staged protocol of external and internal techniques

INTRODUCTION

There is high risk of neurologic complications in one-stage management of severe rigid spinal deformities in adolescents. Therefore, gradual spine stretching variants are applied. One of them is the use of external transpedicular fixation.

PURPOSE

Our aim was to retrospectively study the outcomes of gradual correction with an apparatus for external transpedicular fixation followed by internal fixation used for high-grade kyphoscoliosis in adolescents.

METHODS

Twenty five patients were reviewed (mean age, 15.1 ± 0.4 years). Correction was performed in two stages: 1) gradual controlled correction with the apparatus for external transpedicular fixation; and 2) internal posterior transpedicular fixation. Rigid deformities in eight patients required discapophysectomy. Clinical and radiographic study of the outcomes was conducted immediately after treatment and at a mean long-term period of 3.8 ± 0.4 years. Pain was evaluated using the visual analogue scale (VAS, 10 points). The Oswestry questionnaire (ODI scale) was used for functional assessment.

RESULTS

Deformity correction with the external apparatus was 64.2 ± 4.6% in the main curve and 60.7 ± 3.7% in the compensatory one. It was 72.8 ± 4.1% and 66.2 ± 5.3% immediately after treatment and 70.8 ± 4.6% and 64.3 ± 4.2% at long term, respectively. Pain relieved by 33.2 ± 4.2% (p < 0.05) immediately after treatment and by 55.6 ± 2.8% (p < 0.05) at long term. ODI reduced by 30.2 ± 1.7% (p < 0.05) immediately after treatment and by 37.2 ± 1.6% (p < 0.05) at long term.

CONCLUSION

The apparatus for external transpedicular fixation provides gradual controlled correction for high-grade kyphoscoliosis in adolescents. Transition to internal fixation preserves the correction achieved, and correction is maintained at long term.

Digital Anatomical Measurement for Anterolateral Fixation of Middle and Lower Thoracic Vertebrae

Background

The key to its successful application is to determine the best entry point for the vertebral screw(s). This study aimed to provide a reference for clinical anterolateral fixation through digital measurement of computed tomography (CT) data to identify relevant anatomical positions in the middle and lower thoracic vertebrae (T4–T12) of 30 adults.

Material/Methods

We performed digital measurement of anatomical positions in the middle and lower thoracic vertebrae (T4–T12) of 30 adults. Abbreviations: Left height of vertebral body, LHV; Right height of vertebral body, RHV; Anterior height of vertebral body, AHV; Middle height of vertebral body, MHV; Posterior height of vertebral body, PHV; Superior sagittal diameter of vertebral body, SSDV; Superior transverse diameter of vertebral body, STDV; inferior sagittal diameter of vertebral body, ISDV; Inferior transverse diameter of vertebral body, ITDV; (1) Left (right) height of vertebral body, [L(R)HV]; Anterior (middle, posterior) height of vertebral body [A(M,P)HV]; Superior (inferior) sagittal diameter of vertebral body, [S(I)SDV]; Superior (inferior) transverse diameter of vertebral body, [S(I)TDV].

Results

The transverse diameters of vertebral bodies were always larger than the sagittal diameter for 3~4 mm. The distance between 2 vertebrae (interval of 1 vertebra) range were (52–56) mm for T4–T7 and (44–48) mm for T8–T12, and the surgeons could collate these data to choose a suitable stick length.

Conclusions

Bone graft should prune into laterigrade cuboid, it can recover A-P and bilateral physiological functions load, and the height of the vertebral body increased from T4 to T12.