Radiological and functional outcomes of high-grade spondylolisthesis treated by intrasacral fixation, dome resection and circumferential fusion: a retrospective series of 20 consecutive cases with a minimum of 2 years follow-up

Restoration of Spinopelvic Alignment After Reduction of High-grade Spondylolisthesis: Myth or Reality? A Systematic Review of the literature and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis of literature.

OBJECTIVE

The aim of the presented study is to assess whether the reduction of high-grade spondylolisthesis (HGS) through the correction of lumbosacral kyphosis leads to a decrease in the sagittal spinopelvic compensatory mechanisms.

SUMMARY OF BACKGROUND DATA

HGS is as an anterior translation of a vertebra, >50%. It is also characterized by a kyphotic deformity of the affected level. This combination of translation and kyphosis leads to compensatory mechanisms on the sagittal plane [pelvic retroversion, increased lumbar lordosis (LL), reduction in thoracic kyphosis (TK)].

METHODS

A systematic search of electronic databases was conducted. Inclusion criteria were diagnosis of HGS (Meyerding >II, Slip% >50%), partial or complete reduction surgery (with a significant decrease in Slip%), and report of spinopelvic parameters (pelvic incidence, pelvic tilt, or sacral slope). Clinical and radiographic outcomes were extracted and summarized. Meta-analyses were performed to estimate the differences between preoperative and postoperative spinopelvic alignment measures. P<0.05 was considered significant.

RESULTS

Eighteen studies were included. PT showed a statistically significant decrease of -2.1217 (95% CI: -3.4803 to -0.7630), while SS showed a significant increase of 4.8349 (95% CI: 2.7462-6.9236). Conversely, both LL and TK showed nonsignificant changes, -4.7043 (95% CI: -10.4535 to 1.0449) and 6.3881 (95% CI: -0.8344 to 13.6106), respectively. VAS significantly decreased by -3.1950 (95% CI: -4.9462 to -1.4439).

CONCLUSIONS

The meta-analysis showed mild, yet statistically significant, decrease of PT and an increase in SS after HGS reduction. Conversely, nonstatically significant decrease in LL and an increase in TK occurred. The clinical significance of these results remains questionable.

LEVEL OF EVIDENCE

Level IV.

Utility of intraoperative neurophysiological monitoring in detecting motor and sensory nerve injuries in pediatric high-grade spondylolisthesis

BACKGROUND CONTEXT

Intraoperative neuromonitoring (IONM) during surgical correction of spinal deformity has been shown to reduce iatrogenic injury in pediatric and adult populations. Although motor-evoked potentials (MEP), somatosensory-evoked potentials (SSEP), and electromyography (EMG) have been shown to be highly sensitive and specific in detecting spinal cord and nerve root injuries, their utility in detecting motor and sensory nerve root injury in pediatric high-grade spondylolisthesis (HGS) remains unknown.

PURPOSE

We aim to assess the diagnostic accuracy and therapeutic impact of unimodal and multimodal IONM in the surgical management of HGS.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Pediatric patients undergoing posterior spinal fusion (PSF) for treatment of HGS.

OUTCOME MEASURES

Data on patient demographics, spinopelvic and spondylolisthesis parameters, and the presence of pre-and postoperative neurological deficits were collected.

METHODS

Intraoperative MEP, SSEP, and EMG alerts were recorded. Alert criteria were defined as a change in amplitude of more than 50% for MEP and/or SSEP, with or without change in latency, and more than 10 seconds of sustained EMG activity. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for each modality and the combination of MEP and SSEP. The 95% confidence intervals (CIs) were calculated using the exact (Clopper-Pearson) method.

RESULTS

Fifty-four pediatric patients with HGS undergoing PSF between 2003 and 2021 in a single tertiary center were included. Seventy-two percent (39/54) of patients were female; the average age of patients was 13.7±2.3 years. The sensitivity of MEP in detecting new postoperative neurologic deficit was 92.3% (95% CI [64.0-99.8]), SSEP 77.8% (95% CI [40.0-97.2]), EMG 69.2% (95% CI [38.6-90.9]), and combination MEP and SSEP 100% (95% CI [73.5-100]). The specificity of MEP was 80.0% (95% CI [64.4-91.0]), SSEP 95.1% (95% CI [83.5-99.4]), EMG 65.9% (95% CI [49.4-79.9]), and combination MEP and SSEP 82.9% (95% CI [67.9-92.9]). The accuracy of SSEP was 92.0% (95% CI [80.8%-97.8%]), and the combination of MEP and SSEP was 86.8% (95% CI [74.7%-94.5%]). Twelve (22.2%) patients had a new motor or sensory deficit diagnosed immediately postoperatively. Nine patients made a full recovery, and 3 had some neurologic deficit on final follow-up.

CONCLUSION

Unimodal IONM using SSEP and MEP alone were accurate in diagnosing sensory and motor nerve root injuries, respectively. The diagnostic accuracy in predicting motor and sensory nerve injuries in pediatric HGS improved further with the use of multimodal IONM (combining MEP and SEP). We recommend the utilization of multimodal IONM in all HGS PSF surgeries.

High-grade L5-S1 spondylolisthesis with lumbosacral kyphosis: Long-term results of non-instrumented circumferential arthrodesis in children, adolescents

INTRODUCTION

The choice of surgical technique for high-grade spondylolisthesis (HGS) associated with lumbosacral kyphosis remains controversial. Are non-instrumented techniques still relevant, what with the multiplicity and modernity of patient-specific instrumentation?

HYPOTHESIS

Our hypothesis was that a non-instrumented circumferential arthrodesis performed after a period of gradual reduction of HGS, associated with lumbosacral kyphosis, provided satisfactory long-term functional and radiographic results in children and adolescents while minimizing the risk of complications.

MATERIALS AND METHODS

Thirty-one L5-S1 HGS associated with a lumbosacral kyphosis operated by non-instrumented circumferential arthrodesis after a period of traction and suspension were included in our study. The first stage of this technique consisted of a gradual reduction using traction followed by immobilization in the corrected position. The second stage involved a posterior, followed by an anterior, surgical procedure and a spica cast immobilization for 4 months. The mean age at surgery was 13.9±2.3 years (6-18) and the mean follow-up was 10.3±4.5 years (2.1-17.8).

RESULTS

The overall complication rate was 26% (n=8/31): 13% neurologic complications, 10% bone fusion defects and 3% skin complications. The reoperation rate was 13% (n=4/31). The mean ODI (/50) was 3±4.6 (0-22) and the SRS-30 126.7±15 (72-143). The Taillard index decreased by 25% (p<.001) and remained stable throughout the follow-up period (p=.65). The lumbosacral angle was corrected by 13.5% (p=.03) and the correction was maintained throughout the follow-up period (p=.71). At the last follow-up, the lumbosacral angle was significantly correlated with a low ODI score and a high SRS-30 score (p<.05).

CONCLUSION

Even though this technique achieved a smaller reduction of the lumbosacral angle, it reduced by at least a factor of three the incidence of neurologic complications and resulted in satisfactory functional outcomes when compared to instrumented and intraoperative correction series.

LEVEL OF EVIDENCE

IV.

Stretch on the L5 nerve root in high-grade spondylolisthesis reduction

OBJECTIVE

L5 nerve root (L5-NR) injury after surgery for high-grade spondylolisthesis (HGS) was considered a nerve stretch associated with reduction. Currently, however, no study has directly measured the stretch on the L5-NR during HGS reduction procedures.

METHODS

CT data of 4 patients with mild lumbar degeneration (control group [CG]) and 4 patients with HGS (spondylolisthesis group [SG]) were used for 3D printing to develop L5 vertebrae and sacrum models. These models were mounted on a self-designed reduction apparatus, which performed vertical translation (disc heights of 0, 5, and 10 mm), anterior-posterior translation (reduction, 0%-100%), and slip-angle correction (0° to -30°). The L5-NR was simulated by using a rabbit sciatic nerve. The cephalic side of the nerve was fixed at the upper base of the L5 pedicle, while the caudal side was connected to a high-precision sensor and an indicator to measure the tension (stretch) on the nerve during the reduction procedures in real time.

RESULTS

The SG had shorter L5-NRs than the CG. At a 0-mm disc height, the peak tension on the L5-NR changed from 0 N (reduction 0%) to 1.81 ± 0.54 N (reduction 100%) in the SG and to 1.78 ± 0.71 N in the CG. At a 10-mm disc height, the tension changed from 1.50 ± 0.67 N to 4.97 ± 1.04 N in the SG and from 0.92 ± 0.45 N to 3.26 ± 0.88 N in the CG. In both the CG and SG, at the same disc height, all values from the complete reduction process were statistically significant. Furthermore, at the same degree of reduction, the comparisons between different disc heights were almost all statistically significant. Intergroup comparisons showed that an increased disc height would cause more tension on the L5-NR in the SG than in the CG. At a 10-mm disc height, all results between the groups demonstrated statistical significance. The slip-angle correction produced a slight increase in the tension on the L5-NR in both groups.

CONCLUSIONS

Increased disc height and reduction significantly increased the tension on the L5-NR, which demonstrated a nonlinear curve. The slip-angle correction from 0° to -30° slightly increased the tension on the L5-NR. Under the same degree of reduction and restored disc height, the SG had more tension on the L5-NR than the CG.

Restoration of sagittal alignment in high-grade isthmic spondylolisthesis using the reverse Bohlman technique with anterior lumbar interbody fusion using a hyperlordotic cage at L4–5: illustrative case

BACKGROUND

Circumferential fusion with or without reduction is the preferred treatment for high-grade isthmic spondylolisthesis. Reduction presents significant risk of neurological injury. The authors present one case in which the “reverse Bohlman” technique was used with the addition of a hyperlordotic interbody cage at L4–5 as a means to correct sagittal malalignment while avoiding the reduction of L5 on S1.

OBSERVATIONS

The patient was a 22-year-old woman with a long-term history of lower back pain and bilateral L5 radiculopathy secondary to high-grade isthmic lumbar spondylolisthesis. She underwent anterior lumbar interbody fusion using the reverse Bohlman technique plus a hyperlordotic interbody cage at L4–5, followed by decompression and posterior spinal instrumentation and fusion from L4 to the pelvis. At 2-year follow-up, she was found to have complete resolution of symptoms with clinical and radiographic evidence of fusion. Her spinopelvic parameters had significantly improved.

LESSONS

The reverse Bohlman technique with the addition of a hyperlordotic interbody cage at L4–5 is a potential alternative treatment method to correct sagittal malalignment while avoiding possible injury to the L5 nerve roots that can be seen in the reduction of high-grade isthmic spondylolisthesis.

What is the Optimal Surgical Method for Achieving Correction and Avoiding Neurological Complications in Pediatric High-grade Spondylolisthesis?

BACKGROUND

Controversy persists in the treatment of high-grade spondylolisthesis (HGS). Surgery is recommended in patients with intrusive symptoms and evidence debates the competing strategies. This study compares the radiologic outcomes and postoperative complications at a minimum of 2 years follow-up for patients with HGS treated with instrumented fusion with partial reduction (IFIS) with those treated with reduction, decompression, and instrumented fusion (RIF). We hypothesize that IFIS leads to a lower rate of complication and revision surgery than RIF.

METHODS

A retrospective comparative methodology was used to analyze consecutive HGS treated surgically between 2006 and 2017. Patients diagnosed with ≥grade 3 spondylolisthesis treated with arthrodesis before the age of 18 years with a minimum of 2 years follow-up were included. Patients were excluded if surgery did not aim to achieve arthrodesis or was a revision procedure. Cases were identified through departmental and neurophysiological records.

RESULTS

Thirty patients met the inclusion criteria. Mean follow-up was 4 years. Ten patients underwent IFIS and the remaining 20 underwent RIF. The 2 groups showed no difference in demographics, grade of slip, deformity or presenting symptoms. Of 10 treated with IFIS, the SA reduced by a mean of 10 degrees and C7 sagittal vertical line changed by 31 mm. In the RIF cohort, SA reduced by 16 degrees and C7 sagittal vertical line reduced by 26 mm. PT was unchanged in both groups. In IFIS cohort, 2 patients showed postoperative weakness, resolved by 2 years. None required revision surgery. In the RIF group, 4 sustained dural tears and 1 a laminar fracture, 7 showed postoperative weakness or dysaesthesia, 3 of which had not resolved by 2 years. Eight patients underwent unplanned further surgery, 3 for pseudarthrosis.

CONCLUSIONS

RIF and IFIS show similar radiologic outcomes. RIF shows a higher rate of unplanned return to surgery, pseudarthrosis and persisting neurological changes.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

High-Grade Spondylolisthesis in Adults: Current Concepts in Evaluation and Management

Background

Information regarding the treatment of high-grade spondylolisthesis (HGS) in adults has been previously described; however, previous descriptions of the evaluation and surgical management of HGS do not represent more recent and now established approaches. The purpose of the current review is to discuss current concepts in the evaluation and management of patients with HGS.

Methods

Literature review.

Results

HGS is diagnosed in up to 11.3% of adults with spondylolisthesis and typically presents as nonspecific lower back pain. Regarding evaluation, a thorough history and physical examination should be performed, which may help predict the presence of HGS. Diagnostic imaging, and specifically the use of spino-pelvic parameters, are now commonly implicated in guiding treatment course and prognosis. When surgical intervention is indicated, surgical approaches include in situ fusion variations, reduction and partial reduction with fusion, and vertebrectomy. Although the majority of studies suggest improvements with these approaches, the literature is limited by a low level of evidence with regards to the superiority of one technique when compared with others.

Conclusions

HGS is a unique cause of low back pain in adults that carries considerable morbidity, but rarely presents with neurologic symptoms. Although the definitions, classifications, and methods of diagnosis of this spinal deformity have been established and accepted, the ideal surgical management of this deformity remains highly debated. Fusion in situ techniques are often technically easier to perform and provide lower risk of neurologic complications, whereas reduction and fusion techniques offer greater restoration of global spino-pelvic balance. Preoperative spino-pelvic parameters may have utility in assisting in procedural selection; however, future, higher-quality and longer-term studies are warranted to determine the optimal surgical intervention among the widely available techniques currently used, and to better define the indications for these interventions.