Pedicular lumbosacral spine fusion for adult/adolescent lumbar developmental high-grade spondylolisthesis

INTRODUCTION

Lumbar spondylolisthesis is a common spinal problem and is presented in about 5% of the population. However, high-grade spondylolisthesis (HGS) according to the Meyerding[6] grading [Table 1] remains a relatively uncommon subtype. When it presents in the pediatric and adolescent age groups, HGS is typically attributed to progressive congenital (dysplastic) spondylolisthesis.

Table 1:: The Meyerding grading of spondylolisthesis according to percentage of anteroposterior slippage in the sagittal.

The following pathology characterizes congenital spondylolisthesis; L5 subluxation over the sacrum due to pars defects, hypoplastic L5 and S1 facets, and a “dooming” sacrum.[2] In both adolescents and adults, the majority of HGS has been managed utilizing posterior in situ/noninstrumented lumbosacral arthrodesis which has often been linked to significant pseudoarthrosis rates and other complications.[7] Here, alternatively, we present six cases of pediatric/adolescent L5-S1 HGS successfully managed with transpedicular screw fixation.[1]

MATERIALS AND METHODS

We retrospectively reviewed six consecutive patients with HGS (2016–2020), averaging 19.5 years of age [Table 2]. All had low back pain, with bilateral sciatica; 2 additionally demonstrated neurogenic claudication. Notable, none had focal neurological deficits. Preoperative radiographs uniformly showed congenital (dysplastic) bony anomalies resulting in Grade IV spondylolisthesis (HGS) at L5–S1 [Table 2].

Table 2:: Patient demographics and symptomatology and pathology breakdown.

All six patients underwent transpedicular L3 or L4 to L5-S1 fusions without reduction of the slip. Relief of symptoms (subjectively) was recorded over the minimum follow-up period of 6 postoperative months. Outcomes were evaluated utilizing the visual analog score (VAS) for low back pain and Oswestry disability index (ODI). Further, postoperative radiological bone fusion was documented over a minimum of 6 months on CT scans/plain radiographs. [Figures 1-3].

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Figure 1:: Female patient, house wife, 27 years old, presented by low back pain, bilateral sciatica and flexion attitude. Pre-operative image; (a) Plain x-ray lumbar spine, lateral view, (b) MRI lumbosacral spine, sagittal view showing HGS. Post-operative images CT lumbosacral spine, (c) sagittal view, showing the screws and limit of its reach, (d) axial view showing triangular arrangement of the transvertebral screws, 16 months following surgery.

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Figure 2:: Male student, armature soccer player 17 years old, presented with low back pain, bilateral sciatica and flexion attitude (Resembling tight hamstring). 56 months fu, returned back to his sport. Pre-operative images, (a) Plain x-ray lumbar spine, lateral view, (b) MRI lumbosacral spine, sagittal view showing HGS. Post-operative plain X-ray lumbar images, (c) lateral view, (d) anteroposterior view after screw placement, 21 months following surgery.

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Figure 3:: Female patient, 14 years student, the youngest in our series, present to us with low back pain and unilateral sciatica. Preoperative images; (a) Plain X-ray lumbar spine, lateral and (b) MRI lumbosacral spine, sagittal view showing Grade IV spondylolisthesis. Plain X-rays lumbar spine, (c) intraoperative c-arm image, showing the screws after fully inserted, while patient is in prone position, (d) early postoperative image, lateral view showing the screws in place with patient in standing position.

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RESULTS

There were no major intraoperative complications (e.g., infections, hemorrhages or nerve injuries, and motor deficits), or long-term postoperative complications (e.g., instrumentation failure, slippage progression, or pseudoarthrosis) in these six patients [Figures 1-3]. However, one patient with L4 facet dysplasia underwent bilateral L3 rather than L4 proximal screws [Figure 1c]. The length of hospital stay ranged from 3 to 5 days [Table 3].

Table 3:: Follow data breakdown.

Outcomes

In 5 of 6 patients, radiculopathy improved on VAS and ODI scores (e.g., the latter went from 22 to 64%, mean 40.5% preoperatively, to 5-22% (mean 13.5%) postoperatively) [Table 4]. Only one patient had worsening low back pain postoperatively that gradually improved within 3 months. Fusions were successfully achieved in all six patients, as documented on postoperative lumbar CT scans.

Table 4:: Postoperative symptomatology changes.

DISCUSSION

Most patients with high-grade developmental spondylolistheses (HGS) develop significant slippage and symptoms during the adolescent growth period. Symptoms typically include; the onset of low back and sciatic pain that can evolve into a full-blown sciatic crisis.[1,4]

Surgical techniques for HGS management have included posterior instrumented fusion, posterolateral interbody fusion, stand-alone oblique interbody fusion, anterior fusion, L5 vertebrectomy with reduction and fusion, and circumferential in situ fusion (either two-staged or single staged posterior approach).[3,4] Here, we successfully utilized transpedicular fusion from L3 or L4 to L5-S1 in six patients with HGS. Safe penetration of the anterior sacral cortex with longer sacral screws for deeper penetration of the bone mass, increased their pull-out strength. Further, no patients developed further slippage following the procedures over an average follow-up period of 32 months.

We, therefore, concluded that the transpedicular instrumentation technique was more effective than the typical in situ/noninstrumented L5-S1 HGS fusion for HGS.[5]

CONCLUSION

Transpedicular lumbosacral L3 or L4 to L5-S1 instrumented fusions for grade IV spondylolisthesis/HGS without reduction was successfully performed in six adolescent/ young adults. This resulted in favorable outcomes and was a useful alternative to in situ/noninstrumented HGS lumbosacral fusions.