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

BACKGROUND: Few series report on the management of high-grade spondylolisthesis (HGS) in adolescents and young adults. This review highlights a series of six consecutive cases with developmental (dysplastic) HGS successfully managed with L3 or L4 to S1 transpedicular screw placement, rather than in situ/noninstrumented lumbosacral fusion.
METHODS: The six patients with HGS, according to the Meyerding Grading, presented with low back pain and bilateral sciatica (2016-2020). Patients averaged 19.8 years of age and underwent posterior transpedicular L3 or L4-S1 screw fusions. They were all monitored for at least 6 postoperative months.
RESULTS: None of the six patients developed any major perioperative/postoperative complications; only one patient had severe postoperative back pain that slowly improved over 3 months. All the patients were clinically improved postoperatively, uniformly demonstrated fusion on postoperative CT studies, and considered the operation worthwhile.
CONCLUSION: Posterior transpedicular screw fixation of the lumbosacral spine is an efficient and safe technique for the treatment of L3 or L4 to L5-S1 HGS. It is a suitable instrumented technique for managing adult/adolescent HGS and offers an alternative to the more typically performed in situ/noninstrumented L4-S1 procedures. Copyright:

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].

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.

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.

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.

Surgical technique

Standard L3 or L4 through S1 laminectomies were performed [Figure 1c], accompanied by bilateral exposure of the transverse processes. Under C-arm guidance, 6.5mm thick, and 55–65 mm long lumbar pedicular screws were inserted bilaterally from the S1 pedicle and directed anteromedially through the sacral promontory, crossing the L5-S1 disc space toward the vertebral body of L5 anteriorly, but stopping before its anterior cortex [Figure 1d]. Two pedicular screws were then inserted in either L3 or L4 bilaterally and connected to the sacral screws utilizing two rods; in five cases the fusion extended from L4-S1, while in one case, where the L4 facets were severely dysplastic, bilateral L3 screws were applied.

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.