Outcome of L5 radiculopathy after reduction and instrumented transforaminal lumbar interbody fusion of high-grade L5-S1 isthmic spondylolisthesis and the role of intraoperative neurophysiological monitoring

Postoperative Foot Drop After Spinal Surgery: Etiology, Presentation, and Management Strategies

» The incidence of postoperative foot drop after spine surgery is estimated at 3.33%, with higher rates reported in complex procedures such as high-grade spondylolisthesis correction (up to 30%). Risk factors include disc-space distraction, deformity corrections, prolonged surgery, and advanced patient age.» The primary mechanisms of postoperative foot drop include direct nerve trauma, stretch injuries from retraction or distraction, compression from hematomas or implants, and ischemic damage because of disrupted blood flow.» Preoperative counseling, intraoperative precision, appropriate disc space distraction, and careful nerve retraction are key to mitigating the risk of foot drop, with ongoing research needed to standardize preventive and management guidelines.» Treatment strategies are tailored to the underlying cause, ranging from conservative options (physical therapy, ankle-foot orthoses, and functional electrical stimulation) to surgical interventions (hematoma evacuation, implant removal, neurolysis, nerve transfer, and tendon transfer), although outcomes are highly variable.

Surgical Treatment of Developmental Dysplastic Lumbosacral Spondylolisthesis: Additional Help from an Intervertebral Distraction, Correction, and Reduction Device

BACKGROUND

 In mid- to high-grade adult dysplastic spondylolisthesis, surgeons are faced with three underlying components: angular, translational, and collapse of the disk. In extremely narrow intervertebral spaces, it is difficult to distract and lift the vertebral bodies by the pedicle screw system alone. In this prospective case control study, we analyzed the efficacy of the latest prototypes (distraction, correction, and reduction [DCR] instrument) with intervertebral application in terms of distraction, correction of segmental kyphosis, and slip reduction.

METHODS

 Twelve adult patients (5 male and 7 female patients) were enrolled in this study. The average age was 42 years (range: 17-67 years) and in all cases the maneuver was documented during the surgery. The amount of slip reduction, the lumbosacral angle according to the Spinal Deformity Study Group dysplastic angle (dys-SDGG), and the disk height were measured preoperatively, intraoperatively, 3 months after surgery, and during the latest follow-up (range: 3-44 months). The relative height of the lumbosacral disk was determined in relation to the disk height in L3/L4.

RESULTS

 Slippage ranged from 17 to 67%. Overall, the average slippage was 45% preoperatively and 4.8% after the reduction maneuver. The average ratio of the disk height was 0.3 preoperatively, 1.0 intraoperatively, and 0.9 at the latest follow-up. Two patients showed significant kyphotic changes, and these patients had an 18- and 21-degree lordotic improvement. From those who had a lumbosacral kyphosis >20 degrees, only one patient did not show any lordotic improvement. All other patients had a significant lordotic improvement. In total, the lumbosacral angle changed from 15 to 23 degrees.

CONCLUSION

 The application of an intervertebral distractor with a mobile thigh has a good clinical and radiologic outcome for mid- to high-grade adult dysplastic spondylolisthesis in terms of distraction, kyphosis correction, and reduction of underlying slippage. The described hardware failures and the complications were not related to the DCR device.

Accuracy of Intraoperative Neuromonitoring in the Diagnosis of Intraoperative Neurological Decline in the Setting of Spinal Surgery-A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

In an effort to prevent intraoperative neurological injury during spine surgery, the use of intraoperative neurophysiological monitoring (IONM) has increased significantly in recent years. Using IONM, spinal cord function can be evaluated intraoperatively by recording signals from specific nerve roots, motor tracts, and sensory tracts. We performed a systematic review and meta-analysis of diagnostic test accuracy (DTA) studies to evaluate the efficacy of IONM among patients undergoing spine surgery for any indication.

METHODS

The current systematic review and meta-analysis was performed using the Preferred Reporting Items for a Systematic Review and Meta-analysis statement for Diagnostic Test Accuracy Studies (PRISMA-DTA) and was registered on PROSPERO. A comprehensive search was performed using MEDLINE, EMBASE and SCOPUS for all studies assessing the diagnostic accuracy of neuromonitoring, including somatosensory evoked potential (SSEP), motor evoked potential (MEP) and electromyography (EMG), either on their own or in combination (multimodal). Studies were included if they reported raw numbers for True Positives (TP), False Negatives (FN), False Positives (FP) and True Negative (TN) either in a 2 × 2 contingency table or in text, and if they used postoperative neurologic exam as a reference standard. Pooled sensitivity and specificity were calculated to evaluate the overall efficacy of each modality type using a bivariate model adapted by Reitsma et al, for all spine surgeries and for individual disease groups and regions of spine. The risk of bias (ROB) of included studies was assessed using the quality assessment tool for diagnostic accuracy studies (QUADAS-2).

RESULTS

A total of 163 studies were included; 52 of these studies with 16,310 patients reported data for SSEP, 68 studies with 71,144 patients reported data for MEP, 16 studies with 7888 patients reported data for EMG and 69 studies with 17,968 patients reported data for multimodal monitoring. The overall sensitivity, specificity, DOR and AUC for SSEP were 71.4% (95% CI 54.8-83.7), 97.1% (95% CI 95.3-98.3), 41.9 (95% CI 24.1-73.1) and .899, respectively; for MEP, these were 90.2% (95% CI 86.2-93.1), 96% (95% CI 94.3-97.2), 103.25 (95% CI 69.98-152.34) and .927; for EMG, these were 48.3% (95% CI 31.4-65.6), 92.9% (95% CI 84.4-96.9), 11.2 (95% CI 4.84-25.97) and .773; for multimodal, these were found to be 83.5% (95% CI 81-85.7), 93.8% (95% CI 90.6-95.9), 60 (95% CI 35.6-101.3) and .895, respectively. Using the QUADAS-2 ROB analysis, of the 52 studies reporting on SSEP, 13 (25%) were high-risk, 10 (19.2%) had some concerns and 29 (55.8%) were low-risk; for MEP, 8 (11.7%) were high-risk, 21 had some concerns and 39 (57.3%) were low-risk; for EMG, 4 (25%) were high-risk, 3 (18.75%) had some concerns and 9 (56.25%) were low-risk; for multimodal, 14 (20.3%) were high-risk, 13 (18.8%) had some concerns and 42 (60.7%) were low-risk.

CONCLUSIONS

These results indicate that all neuromonitoring modalities have diagnostic utility in successfully detecting impending or incident intraoperative neurologic injuries among patients undergoing spine surgery for any condition, although it is clear that the accuracy of each modality differs.PROSPERO Registration Number: CRD42023384158.

Irreducible L5/S1 Spondyloptosis in Over 20 Years After Neglected Trauma Treated with Modified Grob's Technique - Case Report

Introduction

Spondyloptosis, characterized by complete slippage of the upper vertebral body relative to the lower vertebral body, is an exceedingly rare condition. Typically, it occurs as a result of a high-energy injury and is promptly managed. It is uncommon for a patient to present to a spinal surgery unit several decades after the initial incident.

Case Report

In this case report, we describe the case of a 62-year-old man who experienced a lumbosacral injury from a fall twenty years prior to seeking treatment. The patient had multiple comorbidities, including obesity and internal medicine conditions. He presented with severe back pain radiating to the lower extremities, accompanied by significant neurogenic chroma and lower extremity weakness. Imaging studies revealed spondyloptosis at the L5/S1 level, along with bony fusion and spinal canal stenosis at the L3/L4 level.

Conclusion

The patient underwent surgical intervention using Grob's direct pediculo-body fixation technique. The postoperative period was uneventful, and over the course of one year of follow-up, the patient experienced a resolution of symptoms and significant improvement in functional capacity.

Perspective: Can intraoperative neurophysiological monitoring (IONM) limit errors associated with lumbar pedicle screw fusions/transforaminal lumbar interbody fusions (TLIF)?

Background

We evaluated whether intraoperative neural monitoring (IONM), including somatosensory evoked potential monitoring (SEP), motor evoked potential monitoring (MEP), and electrophysiological monitoring (EMG), could reduce operative errors attributed to lumbar instrumented fusions, including minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF)/open TLIF.

Methods

Operative errors included retraction/stretch or cauda equina neural/cauda equina injuries that typically occurred during misplacement of interbody devices (IBD) and/or malpositioning of pedicle screws (PS).

Results

IONM decreased the incidence of intraoperative errors occurring during instrumented lumbar fusions (MI-TLIF/TLIF). In one series, significant loss of intraoperative SEP in 5 (4.3%) of 115 patients occurred after placing IBD; immediate removal of all IBD left just 2 patients with new neural deficits. In other series, firing of trigger EMG's (t-EMG) detected intraoperative PS malpositioning, prompted the immediate redirection of these screws, and reduced the need for reoperations. One t-EMG study required a reoperation in just 1 of 296 patients, while 6 reoperations were warranted out of 222 unmonitored patients. In another series, t-EMG reduced the pedicle screw breech rate to 7.78% (1723 PS) from a higher 11.25% for 1680 PS placed without t-EMG. A further study confirmed that MEP's picked up new motor deficits in 5 of 275 TLIF.

Conclusion

SEP/MEP/EMG intraoperative monitoring appears to reduce the risk of surgical errors when placing interbody devices and PS during the performance of lumbar instrumented fusions (MI-TLIF/TLIF).However, IONM is only effective if spine surgeons use it, and immediately address significant intraoperative changes.

A novel less invasive endoscopic-assisted procedure for complete reduction of low-and high-grade isthmic spondylolisthesis performed by anterior and posterior combined approach

PURPOSE

The optimal surgical management of low- and high-grade isthmic spondylolisthesis (LGS and HGS -IS) is debated as well as whether reduction is needed especially for high-grade spondylolisthesis. Both anterior and posterior techniques can be associated with mechanical disadvantages as hardware failure with loss of reduction and L5 injury. We purpose a novel endoscopic-assisted technique (Sled technique, ST) to achieve a complete reduction in two surgical steps: first anteriorly through a retroperitoneal approach to obtain the greatest part of correction and then posteriorly to complete reduction in the same operation.

METHODS

ST efficacy and complications rate were evaluated through a retrospective functional and radiological analysis.

RESULTS

Thirty-one patients, 12 male (38.7%) and 19 female (61.3%), average age: 45.4 years with single level IS underwent olisthesis reduction by ST. Twenty-three IS involved L5 (74.2%), 7 L4 (22.5%) and 1 L3 (3.3%). No intraoperative complications were recorded. One patient required repositioning of a pedicle screw. A significant improvement of functional and radiological parameters (L4-S1 and L5-S1 lordosis) outcomes was recorded (p < 0.001).

CONCLUSION

ST provides a complete reduction in the slippage in LGS and HGS. The huge anterior release as well as the partial reduction in the slippage by the endoscopic-assisted anterior procedure, because of the cage is acting as a "guide rail", facilitate the final posterior reduction, always complete in our series, minimizing mechanical stresses and neurological risks.

CLINICALTRIALS

gov Identifier: NCT03644407.

Surgical management of high-grade paediatric spondylolisthesis: meta-analysis and systematic review

PURPOSE

There is currently no consensus on the management of high-grade spondylolisthesis (HGS) in paediatric populations. The objective of this analysis is to compare the outcomes of reduction followed by fusion (RFF) or in situ fusion (ISF) in paediatric patients.

METHODS

Using major databases, a systematic literature search was performed. Primary studies comparing ISF with RFF in paediatric and adolescent patients were identified. Study data including patient-reported outcomes, complications, and spinopelvic parameters were collected and analysed.

RESULTS

Seven studies were included, comprising 97 ISF and 131 RFF. Average patient age was 14.4 ± 2.1 years and follow up was 8.2 ± 5.1 years. Patients undergoing RFF compared to patients undergoing ISF alone were less likely to develop pseudarthrosis (RR 0.51, 95% CI, [0.26, 0.99], p = 0.05). On average, RFF led to 11.97º more reduction in slip angle and 34.8% more reduction in sagittal translation (p < 0.00001) compared to ISF. There was no significant difference between patient satisfaction and pain at follow up. Neurologic complications and reoperation rates were not significantly different.

CONCLUSIONS

Both RFF and ISF are effective techniques for managing HGS. Performing a reduction followed by fusion reduces the likelihood of pseudarthrosis in paediatric patients. The difference between risk of neurologic complications, need for reoperation, patient satisfaction, and pain outcomes did not reach statistical significance. Correlation with patient-reported outcomes still needs to be further explored. LEVEL 3 EVIDENCE: Meta-analysis of Level 3 studies.

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.

Vertebral Slip Morphology in Dysplastic Spondylolisthesis as a Criterion for the Choice of the L5/S1 Support (ALIF, PLIF, Fibular Graft) in Surgical Treatment

Dysplastic spondylolisthesis is a severe pathological condition, based on dysplastic changes in the lumbosacral part of the spine, that causes the asymmetry of the lumbosacral junction. The appropriate therapeutic algorithm remains controversial. As the gold standard, the surgical reposition of the slipped vertebra and 360° fusion of the affected spinal segment is preferred. Thirty-two patients were operated on between the years 2005 and 2018. Different techniques of 360° fusion, based on the severity of the displacement of the affected vertebral segment, were used. Herein, the advantages and disadvantages of different techniques of interbody fusion are discussed. The slippage and retention after reduction in the vertebrae are evaluated prior to the operation, postoperatively, one year after the surgery, and during follow-up, which was 7 years on average (minimum 2 years for a follow-up). Complications associated with the surgery are evaluated, in addition to the operation time, blood loss, spinopelvic parameters, and patient satisfaction with the surgery. All surgical techniques improved the slippage compared to preoperative conditions. The retention of the reposition was not changed significantly in postoperative controls. The incidence of neurological complications reached 12.5%. Surgical treatment is the only treatment option that successfully addressed the pathological principle of dysplastic spondylolisthesis. All of the surgical methods used led to restoring the symmetry of the lumbar spine, and to the improvement in both radiological parameters and the alleviation of subjective difficulties. The aim of this article is to summarize surgical methods in patients having dysplastic spondylolisthesis with a slip of more than 25%, who were operated on, and to determine the optimal treatment algorithm according to the severity of the slip.

Surgical outcomes with anatomic reduction of high-grade spondylolisthesis revisited: an analysis of 101 patients

OBJECTIVE

The ideal strategy for high-grade L5-S1 isthmic spondylolisthesis (HGS) remains controversial. Critical questions include the impact of reduction on clinical outcomes, rate of pseudarthrosis, and postoperative foot drop. The scope of this study was to delineate predictors of radiographic and clinical outcome factors after surgery for HGS and to identify risk factors of foot drop.

METHODS

This was a single-center analysis of patients who were admitted for HGS, defined as grade III or greater L5 translation according to the Meyerding (MD) classification. Complete postoperative reduction was defined as MD grade I or less and L5 slip < 20%. Forty-six patients completed health-related quality-of-life questionnaires (Oswestry Disability Index, Physical Component Summary of SF-36, and visual analog scale) and ≥ 2 years' follow-up (average 105 months). A 540° approach was used in 61 patients, a 360° approach was used in 40, and L5 corpectomy was used in 17. Radiographic analysis included measures of global spinopelvic balance (e.g., pelvic incidence [PI], lumbar lordosis) and measurement of lumbosacral kyphosis angle (LSA), L4 slope (L4S), L5 slip (%), and postoperative increase of L5-S1 height.

RESULTS

The authors included 101 patients with > 1 year of clinical and radiographic follow-up. The mean age was 26 years. Average preoperative MD grade was 3.8 and average L5 slip was 81%; complete reduction was achieved in 55 and 42 patients, respectively, according to these criteria. At follow-up, LSA correlated with all clinical outcomes (r ≥ 0.4, p < 0.05). Forty patients experienced a major complication. Risk was increased in patients with greater preoperative deformity (i.e., LSA) (p = 0.04) and those who underwent L5 corpectomy (p < 0.01) and correlated with greater deformity correction. Thirty-one patients needed revision surgery, including 17 for pseudarthrosis. Patients who needed revision surgery had greater preoperative deformity (i.e., MD grade and L5 slip) (p < 0.01), greater PI (p = 0.02), and greater postoperative L4S (p < 0.01) and were older (p = 0.02), and these patients more often underwent L5 corpectomy (p < 0.01). Complete reduction was associated with lower likelihood of pseudarthrosis (p = 0.08) and resulted in better lumbar lordosis correction (p = 0.03). Thirty patients had foot drop, and these patients had greater MD grade and L5 slip (p < 0.01) and greater preoperative LSA (p < 0.01). These patients with foot drop more often required L5 corpectomy (p < 0.01). Change in preoperative L4S (p = 0.02), LSA (p < 0.01), and L5-S1 height (p = 0.02) were significantly different between patients with foot drop and those without foot drop. A significant risk model was established that included L4S change and PI as independent variables and foot drop as a dependent variable (82% negative predictive value and 71% positive predictive value, p < 0.01).

CONCLUSIONS

Multivariable analysis identified factors associated with foot drop, major complications, and need for revision surgery, including degree of deformity (MD grade and L5 slip) and correction of LSA. Functional outcome correlated with LSA correction.

Intraoperative neuromonitoring during surgery for lumbar stenosis

The indications for neuromonitoring during lumbar stenosis surgery are defined by the risks associated with patient positioning, the approach, decompression of neural elements, deformity correction, and instrument implantation. The routine use of EMG and SEP alone during lumbar stenosis surgery is no longer supported by the literature. Lateral approach neuromonitoring with EMG only is also suspect. Lumbar stenosis patients often present with multiple co-morbidities which put them at risk during routine pre-surgical positioning. Frequently encountered morbid obesity and/or diabetes mellitus may play a role in monitorable and preventable brachial plexopathy after "superman" positioning or femoral neuropathy from groin pressure after prone positioning, for example. Deformity correction in lumbar stenosis surgery often demands advanced implementation of multiple neuromonitoring modalities: EMG, SEP, and MEP. Because the bulbocavernosus reflex detects the function of the conus medullaris and sacral somato afferent/efferent fibers of the cauda equina, it may also be recorded. The recommendation to record pedicle screw thresholds has become more nuanced as surgeon dependence on 3D imaging, navigation, and robotics has increased. Neuromonitoring in lumbar stenosis surgery has been subject mainly to uncontrolled case series; prospective cohort trials are also needed.

Safety and efficacy of stand-alone anterior lumbar interbody fusion in low-grade L5-S1 isthmic spondylolisthesis

Introduction

Surgical management of isthmic spondylolisthesis is controversial and reports on anterior approaches in the literature are scarce.

Research question

To evaluate the safety and efficacy of stand-alone anterior lumbar interbody fusion (ALIF) in patients with symptomatic low-grade L5-S1 isthmic spondylolisthesis.

Material and methods

All adult patients with isthmic spondylolisthesis of the lumbosacral junction treated in a single institution between 2008 and 2019 with stand-alone ALIF were screened. A titan cage was inserted at L5-S1 with vertebral anchoring screws. Prospectively collected surgical, clinical and radiographic data were analyzed retrospectively.

Results

34 patients (19 men, 15 women, mean age 52.5 ​± ​11.5 years) with a mean follow-up of 3.2 (±2.5) years were analyzed. 91.2% (n ​= ​31) of patients had a low-grade spondylolisthesis and 8.8% (n ​= ​3) grade III according to Meyerding classification. Mean COMI and ODI scores improved significantly from 6.9 (±1.5) and 35.5 (±13.0) to 2.0 (±2.5) and 10.2 (±13.0), respectively after one year, and to 1.7 (±2.5) and 8.2 (±9.6), respectively, after two years. The COMI and ODI scores improved in 86.4% and 80%, respectively, after one year and 92.9% of patients after two years by at least the minimal clinically important difference. No intraoperative complications were recorded. 8.8% (n ​= ​3) of patients needed a reoperation.

Discussion and conclusion

After stand-alone ALIF for symptomatic isthmic spondylolisthesis, the patients improved clinically important after one and two years. Stand-alone ALIF is a safe and effective surgical treatment option for low-grade isthmic spondylolisthesis.

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Report of a series of patients with symptomatic low-grade L5-S1 isthmic spondylolisthesis treated by stand-alone ALIF.

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Patient reported outcomes showed clinically important improvements after one and two years.

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Stand-alone ALIF proved to be a safe and effective technique to treat symptomatic low-grade L5-S1 isthmic spondylolisthesis.

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There were no vascular or other major complications.

L5 Radiculopathy After Formal Reduction of High-Grade SDSG Type 5 and 6 L5-S1 Isthmic Spondylolisthesis with 2-Year Follow-Up

BACKGROUND

Surgery is the main treatment for patients with high-grade L5-S1 isthmic spondylolisthesis, which can result in neurologic complications, but little is known about its clinical course. The present study evaluated the presence of L5 radiculopathy in high-grade L5-S1 spondylolisthesis in adults in pre- and postoperative periods and after a 2-year follow-up.

METHODS

A series of 16 patients who underwent reduction and instrumented fusion for high-grade 5 and 6 spondylolisthesis between 2018 and 2019 were retrospectively evaluated in the pre- and postoperative periods as well as after 6 weeks, 3 months, 6 months, and 1 and 2 years of follow-up. Clinical and surgical data on possible neurological complications of L5 radiculopathy were prospectively collected.

RESULTS

The age was 20.1 ± 12.0 years, and preoperative L5-S1 slip was 89.0%. Five patients presented motor deficit in the preoperative period. In the immediate postoperative period, 9 patients (56%) experienced motor deficits or worsening of the preoperative condition. At the 6-week follow-up, only 1 patient showed resolution of the motor deficit. Three patients presented healed motor deficits after 3 months, and 1 patient demonstrated a healed L5 motor radiculopathy after 6 months. At the 1-year follow-up, only 1 patient exhibited an L5 radiculopathy motor deficit, and at the 2-year follow-up, none of the patients exhibited an L5 radiculopathy motor deficit.

CONCLUSION

L5 radiculopathy was frequent in the preoperative period and increased after reduction and instrumented fusion of high-grade L5-S1 spondylolisthesis in the postoperative period and in the 6-week follow-up. Three and 6 months after the surgery, there were consecutive motor improvements. After 2 years of follow-up, no patients showed neurological deficit of L5 radiculopathy.

LEVEL OF EVIDENCE

2.

CLINICAL RELEVANCE

This is the first study reporting a reduction in complications of L5 neurological motor deficit over a 2-year follow-up in high-grade L5-S1 spondylolisthesis in young adults.

Lumbosacral Spondylolysis and Spondylolisthesis

Repetitive stress on the lumbosacral spine during sporting activity places the athletic patient at risk of developing symptomatic pars defect. Clinical history, physical examination, and diagnostic imaging are important to distinguish spondylolysis from other causes of lower back pain. Early pars stress reaction can be identified with advanced imaging, before the development of cortical fracture or vertebral slip progression to spondylolisthesis. Conservative management is first-line for low-grade injury with surgical intervention indicated for refractory symptoms, severe spondylolisthesis, or considerable neurologic deficit. Prompt diagnosis and management of spondylolysis leads to good outcomes and return to competition for most athletes.

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.

Direct reduction of high-grade lumbosacral spondylolisthesis with anterior cantilever technique - surgical technique note and preliminary results

Backgrounds

Surgical reduction for high-grade spondylolisthesis is beneficial for restoring sagittal balance and improving the biomechanical environment for arthrodesis. Compared to posterior total laminectomy and long instrumentation, anterior lumbar inter-body fusion (ALIF) is less invasive and has the biomechanical advantage of restoring the original disk height and increasing lumbar lordosis, thus improving sagittal balance. However, the application of ALIF is still limited in treating low-grade spondylolisthesis. In this study, we developed a new technique termed anterior cantilever procedure to directly reduce the slippage of high-grade lumbosacral spondylolisthesis. The purpose of our study was to investigate the surgical outcomes of the anterior cantilever procedure followed by ALIF and posterior mono-segment instrumented fixation in high-grade spondylolisthesis.

Methods

All patients with high-grade spondylolisthesis who underwent anterior cantilever procedure followed by anterior lumbar inter-body fusion (ALIF) and posterior mono-segment instrumented fixation between November 2006 and July 2017 were enrolled in our study. The slip percentage, Dubousset’s lumbosacral angle, pelvic tilt, sacral slope, pelvic incidence, and sagittal alignment were measured pre-operatively and postoperatively at the last follow-up. Surgery time, blood loss, complications, and hospital stay were also collected and analysed.

Results

A total of 11 consecutive patients with high-grade spondylolisthesis patients were included and analysed. All of the high-grade spondylolisthesis in our series occurred at the L5-S1 level. The median age was 37 years, and the median follow-up duration was 36 months. The average slip reduction was 30% (60 to 30%, P < 0.01), and the average correction of Dubousset’s lumbosacral angle was 13.8° (84.1° to 97.9°, P < 0.01). The median intra-operative blood loss was 300 mL. All patients attained improved sagittal balance after the operation and achieved solid fusion within 9 months after surgery. No incidences of implant failure, permanent neurological deficit, or pseudarthrosis were recorded at the last follow-up.

Conclusions

Anterior cantilever procedure followed by ALIF and posterior mono-segment instrumented fixation is a valid procedure for treating high-grade spondylolisthesis. It achieved a high fusion rate, partially reduced slippage, and significantly improved lumbosacral angle, while minimizing common complications, such as pseudarthrosis, nerve traction injury, excessive soft tissue dissection, and blood loss in posterior reduction procedures. However, posterior instrumentation is still required to the structural stability in the ALIF procedure.

Level of evidence

IV

Surgical treatment of high-grade spondylolisthesis: Technique and results

Background

Surgical management of high-grade spondylolisthesis is not only challenging but also controversial, from in situ fusion to complete reduction. We report our results of a safe three-stage spinal procedure in a single surgical session with seven patients diagnosed high-grade spondylolisthesis.

Hypothesis

Posterior fixation combined with interbody fusion is effective on reduction, ossification and clinical outcomes in high-grade spondylolisthesis.

Patients and methods

This study is a retrospective review of patients who underwent surgery between 2016 and 2018. The surgical method involved specific installation for deformity reduction, pedicle screw fixation, correction of lumbosacral kyphosis with a specific distraction maneuver, wide decompression, gradual reduction of the deformity, and sometimes maintenance of the reduction with interbody fusion. Patients were checked out at 2, 6 and 12 months and yearly after the procedure. Clinical, radiological, Visual Analogic Scale (VAS) and Oswestry Disability Index (ODI) outcomes measures were collected.

Results

Seven patients with high-grade spondylolisthesis at L5-S1 (2 patients grade II, 4 patients grade IV and 1 patient grade V), with a median age of 37 years [17; 72] were included. Median follow-up was 24 months [12; 25 months]. All patients have a fused joint at 6 months except one. Median lumbosacral angle (LSA) improved from 76°[59; 85] to 94°[76; 104]. Meyerding grade of 2 cases was stable after surgery, 3 cases with loss of two ranks and 2 cases with loss of one rank. The radiological parameters showed statistically significant difference (p = 0.036) postoperatively. There was not deep infection. Medians VAS and ODI showed improved pain and disability scores.

Conclusion

This procedure allows correct reduction rate of high-grade spondylolisthesis with good clinic-radiologic outcomes. Though surgically demanding, it was safe and reproducible.

Level of evidence

IV, retrospective.

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.

Reduction versus In Situ Fusion for Adult High-Grade Spondylolisthesis: A Systematic Review and Meta-Analysis

BACKGROUND

Surgical management of high-grade spondylolisthesis is controversial. Both reduction and in situ fusion are available options, but it remains unclear which approach provides better outcomes. We conducted a systematic review and meta-analysis of studies reporting outcomes following reduction or in situ fusion for adult high-grade spondylolisthesis.

METHODS

PubMed, Embase, Web of Science, and Cochrane databases were last searched on June 24, 2019. We identified 1236 studies after excluding duplicates. After screening, 15 studies were included in the meta-analysis. Random-effects models were used to pool effect estimates.

RESULTS

A total of 188 patients were analyzed. Compared with reduction, in situ fusion had a higher mean estimated blood loss (584 mL vs. 451 mL) and a clinically higher incidence of neurologic (48% vs. 15%), pseudarthrosis (13% vs. 8%), and infectious (20% vs. 10%) complications; however, these differences were not statistically significant. Reduction was associated with a clinically higher incidence of overall complications (32% vs. 25%) and dural tears (22% vs. 7%). Reduction provided better pain relief (mean difference [MD] = 5.24 vs. 4.77) and greater change in pelvic tilt (MD = 5.33 vs. 2.60); however, these differences were not statistically significant. Patients who underwent reduction had significantly greater decline in Oswestry Disability Index scores (MD = 55.7 vs. 11.5; P_interaction < 0.01) and greater change in slip angle (MD = 25.0 vs. 11.4; P_interaction = 0.01).

CONCLUSIONS

In management of adult high-grade spondylolisthesis, both approaches appeared to be safe and effective. Reduction appeared to offer better disability relief and spinopelvic parameter correction than in situ fusion.

A ball-slide-type interbody distractor is effective in posterior reduction and internal fixation for patients with mid- to high-grade isthmic spondylolisthesis enrolled in a randomized clinical trial

STUDY DESIGN

Clinical and radiographic results of a randomized, controlled, double-blind clinical trial OBJECTIVE:: To investigate the clinical applicability of a ball-point slide-type interbody distractor in posterior reduction and internal fixation for mid- to high-grade isthmic spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Posterior reduction and internal fixation is the effective treatment for spondylolisthesis. However, for the mid and high-grade isthmic spondylolisthesis patients with the conditions of vertebral osteoporosis and extremely narrow intervertebral space, the reduction is difficult; post-surgery intervertebral space height lost becomes serious; the fracture and loosening rate of fixation system is higher. No study regarding the prevention of these adverse outcomes in this technique is reported.

METHODS

A total of 59 patients of mid and high-grade isthmic spondylolisthesis were randomly divided into random groups (investigational group and control group) applying simple randomized method in this study. In addition, 30 patients received posterior reduction and internal fixation as control. Twenty-nine patients received posterior reduction and internal fixation by ball-point slide-type interbody distractor were assigned to the investigational group. X-ray examination was performed before and after operation. The degree of reduction, height of intervertebral space were compared. The preoperative and postoperative Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) were evaluated. Additionally, rate of the fixation system fracture was also assessed.

RESULTS

Before treatment, there were no significant differences in ISH (P = .72), DR (P = .85), VAS of back pain (P = .55), VAS of leg pain (P = .83) and ODI (P = .68) were found between 2 groups. After 12-month treatment, there were no significant differences in ISH (P = .26), VAS of back pain (P = .09) and VAS of leg pain (P = .96) between two groups. Significant differences of DR (P = .02), ODI (P = .03) and adverse events (P = .00) were found between 2 groups.

CONCLUSIONS

The results of this prospectively study showed that the ball-point slide-type interbody distractor in the posterior reduction and internal fixation produced good outcomes after 12-month treatment. More high quality randomized controlled trials and cases should still be needed to warrant the results of this study.

The reliability of motor evoked potentials to predict dorsiflexion injuries during lumbosacral deformity surgery: importance of multiple myotomal monitoring

STUDY DESIGN

Case-control analysis of transcranial motor evoked potential (MEP) responses and clinical outcome.

OBJECTIVE

To determine the sensitivity and specificity of MEPs to predict isolated nerve root injury causing dorsiflexion weakness in selected patients having complex lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

The surgical correction of distal lumbar spine deformity involves significant risk for damage to neural structures that control muscles of ankle and toe dorsiflexion. Procedures often include vertebral translation, interbody fusion, and posterior-based osteotomies. The benefit of using MEP monitoring to predict dorsiflexion weakness has not been well-established. The purpose of this paper is to describe the relationship between neural complications from lumbar surgery and intraoperative MEP changes.

METHODS

Included were 542 neurologically intact patients who underwent posterior spinal fusion for the correction of distal lumbar deformity. Two myotomes, including tibialis anterior (TA) and extensor hallucis longus (EHL), were monitored. MEP and free-running electromyography data were assessed in each patient. Cases of new dorsiflexion weakness noted postoperatively were identified. Data in case and control patients were compared. There was no direct funding for this work. The Department of Anesthesiology and Perioperative Care provides salary support for authors one and six. Authors two and three report employment in the field of intraoperative neurophysiological monitoring as a study-specific conflict of interest.

RESULTS

Twenty-five patients (cases) developed dorsiflexion weakness. MEP amplitude decreased in the injured myotomes by an average of 65 ± 21% (TA) and 60±26% (EHL), which was significantly greater than the contralateral uninjured side or for control subjects. (p < .01) Receiver operator characteristic (ROC) curves showed high sensitivity, specificity, and predictive value for changes in MEP amplitude using either the TA or EHL. Analysis of MEP changes to either TA or EHL yielded a superior ROC curve. Net reclassification improvement analysis showed assessing MEP changes to both TA and EHL improved the predictability of injury.

CONCLUSIONS

The use of MEP amplitude change is highly sensitive and specific to predict a new postoperative dorsiflexion injury. Monitoring two myotomes (both TA and EHL) is superior to relying on MEP changes from a single myotome. Electromyography activity was less accurate but compliments MEP use. Additional studies are needed to define optimal intraoperative MEP warning thresholds.

The impact and value of uni- and multimodal intraoperative neurophysiological monitoring (IONM) on neurological complications during spine surgery: a prospective study of 2728 patients

PURPOSE

We compared the value of different uni- and multimodal intraoperative neurophysiological monitoring (IONM) methods on the detection of neurological complications during spine surgery.

METHODS

IONM data derived from sensory spinal and cortical evoked potentials combined with continuous electromyography monitoring, motor evoked potentials and spinal recording were evaluated in relation to subsequent post-operative neurological changes. Patients were categorised based on their true-positive or true-negative post-operative neurological status.

RESULTS

In 2728 consecutive patients we had 909 (33.3%) IONM alerts. We had 8 false negatives (0.3%) with post-operative radicular deficit that completely recovered within 3 months, except for one. There was no false negative for spinal cord injury. 107 were true positives, and 23 were false positives. Multimodal IONM sensitivity and specificity were 93.0% and 99.1%, respectively. The frequency of neurological complications including minor deficits was 4.2% (n = 115), of which 0.37% (n = 10) were permanent. Analysis of the single IONM modalities varied between 13 and 81% to detect neurological complications compared with 93% when using all modalities.

CONCLUSION

Multimodal IONM is more effective and accurate in assessing spinal cord and nerve root function during spine surgeries to reduce both neurological complications and false-negative findings compared to unimodal monitoring. We recommend multimodal IONM in all complex spine surgeries. These slides can be retrieved from Electronic Supplementary Material.