Reduction Of High-grade Spondylolisthesis Research Articles

Reduction of high-grade spondylolisthesis using minimally invasive spine surgery-transforaminal lumbar interbody fusion "trial-in-situ" technique: a technical note with case series.

This retrospective case series evaluated the effectiveness of minimally invasive spine surgery-transforaminal lumbar interbody fusion (MIS-TLIF) using the "trial-in-situ " technique for reducing high-grade spondylolisthesis. The surgical management of grade ≥III spondylolisthesis has been controversial, with various methods documented in the literature, including in-situ fusion, in-situ trans-sacral delta fixation, distraction techniques, and external reduction techniques. Recently, MIS techniques have gained popularity. This study analyzed 18 cases of high-grade spondylolisthesis treated with MIS-TLIF using the "trial-in-situ " technique. The clinical outcomes were assessed using the Visual Analog Scale (VAS) and the modified Oswestry Disability Index (mODI) scores. The spinopelvic parameters and sagittal balance were also analyzed. Preoperatively, the spinopelvic parameters were deranged, with a mean pelvic tilt of 28.31°, which improved to 13.91° postoperatively. Similarly, the sacral slope improved from 45.65° to 38.01°. VAS and mODI scores improved postoperatively, indicating the effectiveness of the "trial-in-situ " technique in reducing high-grade spondylolisthesis and achieving a better sagittal profile and spinopelvic parameters. The findings indicate that MIS-TLIF using the "trial-in-situ " technique is a viable and effective method for treating high-grade spondylolisthesis.

Clinical and radiological outcomes of gradual reduction and circumferential fusion of high-grade spondylolisthesis in adolescents: a prospective cohort study of 29 young patients.

The objective of this study was to evaluate the safety and efficacy of a novel technique of formal reduction and circumferential fusion for pediatric high-grade spondylolisthesis (HGS). The safety and efficacy of formal reduction for high-grade spondylolisthesis (HGS) has never been thoroughly examined. This study reports the outcomes of 29 children with HGS who underwent a procedure of gradual reduction and circumferential fusion. 29 children (13 males, 16 females) were recruited between 2006 and 2010. Radiographic measurements (including % of slip, lumbosacral angle-LSA, pelvic incidence-PI, pelvic tilt-PT, sacral slope-SS, and proximal femoral angle-PFA) and quality of life assessment (SRS-22 questionnaire) were prospectively obtained at baseline and at the last post-operative follow-up (> 2years post-op). Radiological measurements were used to classify patients according to the Spine Deformity Study Group (SDSG) classification. Mean baseline slip % was 69.9 ± 16.5%. There were 13 patients with a balanced pelvic (SDSG Type 4) and 16 with an unbalanced pelvis (SDSG Type 5 and 6). On average, a reduction of 45.5 ± 15.3% (range 20-86%) was achieved safely with no major complication. In particular, of the 29 patients, only 3 had a L5 radiculopathy postoperatively that was self-resolved at follow-up. From a radiological standpoint, we observed a mean improvement of LSA from 80.3 ± 17.9° to 91.7 ± 13.6°. We also observed a statistically significant improvement in global HRQOL, and in the function and body image domains. This prospective study suggests that formal reduction of HGS followed by circumferential fusion is safe when using a standardized surgical technique based on gradual reduction. Performing this intervention could also help improve QOL in some patients.

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

Systematic review and meta-analysis of literature. 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. 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)]. 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. 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). 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 IV.

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

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. 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. 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. 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.

A novel anatomo-physiologic high-grade spondylolisthesis model to evaluate L5 nerve stretch injury after spondylolisthesis reduction

L5 nerve palsy is a well-known complication following reduction of high-grade spondylolisthesis. While several mechanisms for its occurrence have been proposed, the hypothesis of L5 nerve root strain or displacement secondary to mechanical reduction remains poorly studied. The aim of this cadaveric study is to determine changes in morphologic parameters of the L5 nerve root during simulated intraoperative reduction of high-grade spondylolisthesis. A standard posterior approach to the lumbosacral junction was performed in eight fresh-frozen cadavers with lumbosacral or lumbopelvic screw fixation. Wide decompressions of the spinal canal and L5 nerve roots with complete facetectomies were accomplished with full exposure of the L5 nerve roots. A 100% translational slip was provoked by release of the iliolumbar ligaments and cutting the disc with the attached anterior longitudinal ligament. To evaluate the path of the L5 nerves during reduction maneuvers, metal bars were inserted bilaterally at the inferomedial aspects of the L5 pedicle at a distance of 10 mm from the midpoint of the L5 pedicle screws. There was no measurable change in length of the L5 nerve roots after 50% and 100% reduction of spondylolisthesis. Mechanical strain or displacement during reduction is an unlikely cause of L5 nerve root injury. Further anatomical or physiological studies are necessary to explore alternative mechanisms of L5 nerve palsy in the setting of high-grade spondylolisthesis correction, and surgeons should favor extensive surgical decompression of the L5 nerve roots when feasible.

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

IntroductionThe 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? HypothesisOur 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 methodsThirty-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). ResultsThe 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). ConclusionEven 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 evidenceIV.

Does the Surgical Reduction of High Grade Spondylolisthesis Restore Spino-Pelvic Alignment? An Analysis of 35 Patients.

Study DesignRetrospective case series.PurposeThis study aimed to analyze how the sagittal spinopelvic alignment is influenced by an attempted surgical reduction of the L5–S1 segment in patients with high-grade spondylolisthesis (HGS).Overview of LiteratureConventional treatment strategies stress the importance of achieving fusion across the lumbosacral junction in patients with HGS. The role of reduction in this subset of patients is controversial.MethodsThis is a retrospective case series of 35 patients with Meyerding grades III, IV, or V spondylolisthesis who underwent surgical treatment in our institution. Before and after surgery, we took standing lateral radiographs from L1 vertebra to pelvis, including the femoral heads, and measured the slip grade, pelvic incidence, sacral slope, pelvic tilt, lumbosacral angle, and lumbar lordosis. Patients were subdivided into “balanced” and “unbalanced” pelvis groups. To determine the effect and correlation of reduction on these spinopelvic parameters, we statistically compared the pre- and postoperative measurements.ResultsThe average follow-up was 9 months (range, 3–169 months). Slip grade improved from an average 74.0%±13.2% to 30.0%±14.0% (p<0.001), and lumbosacral angle reduced from an average 32.0°±11.6° to 6.0°±0.6° (p<0.001). Although the pelvic tilt was reduced, this was not significant. There was a modest negative correlation between the reduction in slip grade and the increase in sacral slope (r=−0.3, p=0.06). At follow-up, five patients improved, from an unbalanced pelvis to a balanced pelvis. Fusion occurred in 33 patients (95%).ConclusionsSurgical reduction of HGS restores the lumbosacral alignment. However, a similar trend is not noted with the pelvic parameters.

Sacropelvic Fixation: A Comprehensive Review

Sacropelvic fixation is indicated in various clinical settings, most notably long spinal arthrodesis, reduction of high-grade spondylolisthesis, and complex sacral fractures. The sacropelvis is characterized by complex regional anatomy and poor bone quality. These factors make achieving solid fusion across the lumbosacral junction challenging. However, a better understanding of spinal biomechanics at that level has led to much higher fusion rates than those of the past. The newer fixation techniques are biomechanically superior to previous methods mainly because they achieve bony purchase anterior to the pivot point—first described by McCord et al. in 1994. Today, the two most widely used fixation techniques are iliac screws and S2-alar-iliac screws. Although these techniques are associated with very high rates of fusion, instrumentation-related pain and reoperation remain problematic. This review provides an overview of the regional anatomy and biomechanics at the lumbosacral junction, as well as a summary of fixation techniques with an emphasis on the most widely used techniques today. Level of EvidenceIV.

The impact of surgical reduction of high-grade lumbosacral spondylolisthesis on proximal femoral angle and quality of life

BACKGOUND CONTEXTAbnormal proximal femoral angle (PFA) was recently found to be associated with deteriorating sagittal balance and quality of life (QoL) in high-grade spondylolisthesis (HGS). However, the influence of PFA on the QoL of patients undergoing surgery remains unknown. PURPOSEThis study compares the pre- and postoperative measurements of sagittal balance including PFA in patients with lumbosacral HGS after surgery. It also determines if PFA is a radiographic parameter that is associated with QoL in patients undergoing surgery. STUDY DESIGNRetrospective cohort study. PATIENT SAMPLEThirty-three patients (mean age 15.6 ± 3.0 years) operated for L5-S1 HGS between July 2002 and April 2015. Thirteen had in situ fusion and 20 had reduction to a low-grade slip. OUTCOME MEASURESThe outcome measures included PFA and QoL scores measured from the Scoliosis Research Society SRS-30 QoL questionnaire. METHODSThe minimum follow-up was 2 years. PFA and QoL were compared pre- and postoperatively. Statistical analysis used nonparametric Mann-Whitney and Wilcoxon Signed Rank tests, Chi-square tests to compare proportions, and bivariate correlations with Spearman's coefficients. RESULTSA decreasing PFA correlated with less pain (r = −0.56, p = .010), improved function (r = −0.51, p = .022) and better self-image (r = −0.46, p = .044) postreduction. Reduction decreased PFA by 5.1° (p = .002), whereas in situ fusion did not alter PFA significantly. Patients with normal preoperative PFA had similar postoperative QoL regardless of the type of surgery, except for self-image, which improved further with reduction (3.73 ± 0.49 to 4.26 ± 0.58, p = .015). Patients with abnormal preoperative PFA tended to have a higher QoL in all domains after reduction. CONCLUSIONDecreasing PFA correlates with less pain, better function and self-image. Reduction of HGS decreases PFA. Reduction also relates to a better postoperative QoL when the preoperative PFA is abnormal. When the preoperative PFA is normal, in situ fusion is equivalent to reduction except for self-image, which is better improved after reduction.

Wednesday, September 26, 2018 1:00 PM – 2:00 PM Navigation and Intraoperative Monitoring: 43. Direct nerve root stimulation: a novel approach to neuromonitoring for reduction of high grade spondylolisthesis

BACKGROUND CONTEXT Traditional methods of neuromonitoring for spinal deformity cases lack accuracy and reproducibility in monitoring for high grade spondylolisthesis. Free run electromyography (EMG) has not been shown to be accurate in detecting radicular injuries in lumbar degenerative surgeries. PURPOSE The purpose of this project is to introduce direct nerve stimulation as a novel alternative to nerve root monitoring in the reduction of high grade spondylolisthesis. METHODS Prospectively collected intraoperative neuromonitoring data including MEP, SSEP and free run EMG, was collected on pediatric patients undergoing posterior reductions for high grade L5 or S1 spondylolisthesis. A fourth modality using direct nerve root stimulation (DNS) of the L5 and S1 nerve roots was recorded by placing a stimulator directly on the exposed nerve root and recording threshold stimulus. Along with the other modalities, DNS was carried out prior to reduction, following all reduction maneuvers and prior to closure. RESULTS Five patients with high grade spondylolisthesis were analyzed, four with Grade IV and one with Grade V. All patients had positive bilateral straight leg raises. Four of 5 patients had intact preoperative lower extremity motor examinations, with one patient having left-sided 4/5 EHL weakness. Three patients did not have any neuromonitoring alerts during their surgical procedure. Their average change in threshold value from baseline to final stimulation in these cases for the L5 nerve root was 1.3 mA. Two patients had intraoperative alerts of MEPs, SSEPs and EMGs which resulted in greater nerve root stimulation threshold values at closing compared to baseline. One patient showed a three-fold increase in DNS threshold while a second patient had a 25-30-fold increase. In both cases, further nerve root exploration and decompression was performed. Both cases resulted in immediate postoperative neurologic deficits in bilateral ankle dorsiflexion. CONCLUSIONS After establishing a prereduction threshold of direct nerve stimulation, increases in DNS threshold were associated with postoperative neurologic deficits in cases of posterior reduction of high grade spondylolisthesis. DNS provided an accurate measure of nerve function in this series. Recognizing increases in DNS thresholds intraoperatively can alert the surgeon to potential real time nerve injuries. A larger multicenter series can help determine the utility of this technique. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Traditional methods of neuromonitoring for spinal deformity cases lack accuracy and reproducibility in monitoring for high grade spondylolisthesis. Free run electromyography (EMG) has not been shown to be accurate in detecting radicular injuries in lumbar degenerative surgeries. The purpose of this project is to introduce direct nerve stimulation as a novel alternative to nerve root monitoring in the reduction of high grade spondylolisthesis. Prospectively collected intraoperative neuromonitoring data including MEP, SSEP and free run EMG, was collected on pediatric patients undergoing posterior reductions for high grade L5 or S1 spondylolisthesis. A fourth modality using direct nerve root stimulation (DNS) of the L5 and S1 nerve roots was recorded by placing a stimulator directly on the exposed nerve root and recording threshold stimulus. Along with the other modalities, DNS was carried out prior to reduction, following all reduction maneuvers and prior to closure. Five patients with high grade spondylolisthesis were analyzed, four with Grade IV and one with Grade V. All patients had positive bilateral straight leg raises. Four of 5 patients had intact preoperative lower extremity motor examinations, with one patient having left-sided 4/5 EHL weakness. Three patients did not have any neuromonitoring alerts during their surgical procedure. Their average change in threshold value from baseline to final stimulation in these cases for the L5 nerve root was 1.3 mA. Two patients had intraoperative alerts of MEPs, SSEPs and EMGs which resulted in greater nerve root stimulation threshold values at closing compared to baseline. One patient showed a three-fold increase in DNS threshold while a second patient had a 25-30-fold increase. In both cases, further nerve root exploration and decompression was performed. Both cases resulted in immediate postoperative neurologic deficits in bilateral ankle dorsiflexion. After establishing a prereduction threshold of direct nerve stimulation, increases in DNS threshold were associated with postoperative neurologic deficits in cases of posterior reduction of high grade spondylolisthesis. DNS provided an accurate measure of nerve function in this series. Recognizing increases in DNS thresholds intraoperatively can alert the surgeon to potential real time nerve injuries. A larger multicenter series can help determine the utility of this technique.

Long-Term Experience With Reduction Technique in High-Grade Spondylolisthesis in the Young.

Surgical management of high-grade spondylolisthesis in the young is not only challenging but also controversial, from in-situ fusion to complete reduction. It is fraught with dangers such as neurological injury, pseudoarthrosis, and progressive deformity with subsequent global sagittal imbalance. We describe our experience of progressive reduction technique and restoration of lumbosacral alignment. This study is a retrospective review of patients who underwent surgery between 1998 and 2012. The surgical technique involved positioning the hips in extension with traction, pedicle screw fixation, correction of lumbosacral kyphosis with a specific distraction maneuver, wide decompression, and gradual reduction of the deformity and maintenance of reduction with interbody fusion. All patients were serially assessed at 1, 3, and 6 months and yearly thereafter with clinical, radiological, and Oswestry Disability Index and Visual Analogue Scale outcome measures. Twenty-seven patients with high-grade spondylolisthesis at L5-S1 (3 cases grade 3, 7 grade 4, 17 grade 5) with an average age of 13.9 years were reviewed. Mean follow-up was 120 months (range 24-192). All patients presented a solid fusion at the 6-month visit; mean slip percentage was reduced from 89% to 23%, with all cases reduced to grade 2 or less. The slip angle improved from 45° to 3° postoperatively, with improvement in sacral slope from 13° to 35°. Four spondyloptosis patients had concomitant scoliosis which corrected spontaneously after the surgery and did not need further intervention. All but one patient (96.2%) had good functional outcomes and returned to their full normal activities. One patient developed a deep infection necessitating implant removal, with eventual deformity progression leading to a poor outcome. Three patients (11.1%) suffered partial drop foot that resolved in full by 12 weeks. Our technique demonstrated a significant reduction of high grade spondylolisthesis, with restoration of global sagittal balance via correction of the lumbosacral kyphosis. Though surgically demanding, it is safe and reproducible. IV.

Does the Surgical Reduction of High Grade Spondylolisthesis Restore Spino-Pelvic Alignment? An Analysis of 35 patients

Does the Surgical Reduction of High Grade Spondylolisthesis Restore Spino-Pelvic Alignment? An Analysis of 35 patients

A Multicenter Evaluation of Clinical and Radiographic Outcomes Following High-grade Spondylolisthesis Reduction and Fusion.

A retrospective review of the clinical and radiographic outcomes from a multicenter study of surgical treatment for high-grade spondylolisthesis (HGS) in adults. The objective was to assess the safety of surgical reduction, its ability to correct regional deformity, and its clinical effectiveness. Retrospective, multicenter review of adults (age above 18 y) with lumbosacral HGS (Meyerding grade 3-5) treated surgically with open decompression, attempted reduction, posterior instrumentation, and interbody fusion. Preoperative and postoperative assessment of the Meyerding grade, slip angle, and sacral inclination were performed based on standing radiographs. Preoperative visual analog scale scores were compared with those at the mean follow-up period. Prolo and Oswestry Disability Index scores at most recent follow-up were assessed. A total of 25 patients, aged 19-72 years, met inclusion criteria. Seventeen interbody cages were placed, including 15 transforaminal lumbar interbody fusions, 1 posterior lumbar interbody fusion, and 1 anterior lumbar interbody fusion. Five patients required sacral dome osteotomies. The average follow-up was 21.3 months.At most recent follow-up there was a statistically significant improvement in both the Meyerding grade and the slip angle (P<0.05). There was 1 intraoperative complication resulting in a neurological deficit (4%) and 1 intraoperative vertebral body fracture (4%). No additional surgery was required for any of these patients. There were no cases of nonunion or device failure except for 1 patient who suffered an unrelated traumatic injury 1 year after surgery. The mean Oswestry Disability Index and Prolo scores at mean follow-up of 21.3 months were 20% (minimum disability) and 8.2 (grade 1), respectively. The present study suggests that reduction, when accomplished in conjunction with wide neural element decompression and instrumented arthrodesis, is safe, effective, and durable with low rates of neurological injury, favorable clinical results, and high-fusion rates.

Long Term Experience with Reduction Technique in High Grade Spondylolisthesis in the Young

Introduction Surgical management of high grade spondylolisthesis in the young is not only challenging but also controversial, from in-situ fusion to complete reduction. It is fraught with dangers such as neurological injury, pseudoarthrosis and progressive deformity with subsequent global sagittal imbalance. We describe our experience of progressive reduction technique and restoration of lumbosacral alignment. Material and Methods A retrospective review of patients who underwent surgery between 1998 and 2012. The surgical technique involved positioning the hips in extension with traction, pedicle screw fixation, correction of lumbosacral kyphosis with a specific distraction maneuver, wide decompression, and gradual reduction of the deformity and maintenance of reduction with interbody fusion. All patients were serially assessed at 1, 3, 6 months and yearly thereafter with clinical, radiological and outcome measures (ODI and VAS). Results 27 patients with high grade spondylolisthesis at L5-S1 (3 cases Grade 3, 7 Grade 4, 17 Grade 5) with an average age of 13.9 years were reviewed. Mean follow-up was 120 months (range 24–192). All patients presented a solid fusion at the 6 month visit; mean slip percentage was reduced from 89% to 23%, with all cases reduced to grade 2 or less. The slip angle improved from 45° to 3° postoperatively, with improvement in sacral slope from 13° to 35°. 4 spondyloptosis patients had concomitant scoliosis which corrected spontaneously after the surgery and did not need further intervention. All but one patient (96.2%) had good functional outcomes and returned to their full normal activities. One patient developed a deep infection necessitating implant removal, with eventual deformity progression leading to a poor outcome. Three patients (11.1%) suffered partial drop foot that resolved in full by 12 weeks. Conclusion Our technique demonstrated a significant reduction of high grade spondylolisthesis, with restoration of global sagittal balance via correction of the lumbosacral kyphosis. Though surgically demanding, it is safe, reproducible and gives satisfying outcomes.

Reduction of high-grade spondylolisthesis through a posterior approach and restoration of the pelvic parameters

BACKGROUND CONTEXT: High-grade spondylolisthesis presents a significant surgical challenge and traditional surgery has ranged from in situ fixation to major reconstructive surgery with high rates of morbidity.

Biomechanics of high-grade spondylolisthesis with and without reduction.

The clinical advantages of reducing spondylolisthesis over fusion in situ have several intuitive reasons such as restore the spinal column into a more anatomic relationship and alignment. However, there is only little evidence in the literature supporting the theoretical advantages of reduction, and its effect on spinopelvic alignment remains poorly defined. In this study, a comprehensive finite element model was developed to analyze the biomechanics of the spine after spinal fusion at L5-S1 in both types of high-grade spondylolisthesis (balanced and unbalanced pelvis). The relevant clinical indices (i.e. spondylolisthesis gradeand Dubousset lumbosacral angle), the displacement of L4-L5, pressure within the annulus and nucleus, and stress at L4-L5 were evaluated and compared. The model can well predict the changes of the important clinical indices during the surgery. For a balanced pelvis, the reduction has a minimal effect on the biomechanical conditions at the adjacent level during postsurgical activities. In the unbalanced case, reduction induced larger deformation in the lumbosacral region and a higher stress concentration at adjacent level. Whether such a stress concentration can lead to long-term disc degeneration is not known. The results provide additional information for the clinician considering reduction of high-grade spondylolisthesis.

Reduction of high-grade lumbosacral spondylolisthesis by minimally invasive transforaminal lumbar interbody fusion: A technical note

Abstract Objective To demonstrate the feasibility and efficacy of reduction of high-grade lumbosacral spondylolisthesis via a minimally invasive approach. Summary of background data Reduction of high-grade spondylolisthesis remains controversial and technically challenging. Although minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has gained wide acceptance in recent years, it still has not been reported to achieve complete reduction of high grade slips. Methods In this technical note, the authors present a case of L5/S1 Meyerding Grade III fixed spondylolisthesis managed by MI-TLIF with percutaneous screws. Surgical techniques and key steps for reduction are described in detail. Results A 50-year-old woman had low back pain for 8 years. She also presented with radiculopathy of lower limbs and frequency/urgency of urination. The radiographs and computed tomography (CT) of the lumbar spine demonstrated degenerative spondylolisthesis, Meyerding grade III, at the level of L5/S1. The slippage was fixed on dynamic radiographs and there was neuroforaminal stenosis on the magnetic resonance image. The patient underwent MI-TLIF with percutaneous pedicle screw-rod fixation for arthrodesis at L5/S1. Her symptoms subsided after the operation. The one-and-half year follow-up radiographs, including CT, demonstrated complete reduction of the high-grade slippage and fusion of the lumbosacral spondylolisthesis. Conclusion Minimally invasive TLIF is a viable option for reduction of high-grade spondylolisthesis at L5/S1.

Assistance with Reduction of High-Grade Spondylolisthesis Using Temporary Alar Distraction Rods and Sacral Dome Osteotomy in Correcting High-Grade Spondylolisthesis: Technique, Complications and Outcomes

Assistance with Reduction of High-Grade Spondylolisthesis Using Temporary Alar Distraction Rods and Sacral Dome Osteotomy in Correcting High-Grade Spondylolisthesis: Technique, Complications and Outcomes

Instrumented Reduction of High-Grade Spondylolisthesis with Distal Anchorage Using Iliac Screws Versus S2 Screws: A Comparison of Techniques, Complications and Results

Instrumented Reduction of High-Grade Spondylolisthesis with Distal Anchorage Using Iliac Screws Versus S2 Screws: A Comparison of Techniques, Complications and Results

Problems in Reduction of High-Grade Spondylolisthesis

There has been discussion about surgical strategies for treatment of high-grade isthmic spondylolisthesis(grade III or IV). Reduction is combined unnecessary by many authors because of the reliability of in situ fusion. However, some investigator have stated a need for reduction is not only restoration of normal spinal alignment and biomechanics; A reduced position is believed to enhance fusion, relieve neurological abnormalities and pain, and improve the cosmetic appearance. Many different techniques have been developed for reduction of spondylolisthesis after Jenkin’s initial description in 1936. The techniques include halofemoral traction, cast reduction, instrumentation, L5 corpectomy, and the combined anterior and posterior approach. Recently, newly developed pedicular instrumentation was widely used to reduce high-grade spondylolisthesis and had high fusion rates. But these instrumentations cannot prevent complications such as nerve root lesions due to the traction on the L5 root during reduction. Anyway, there is much controversy about the most effective surgical treatment option for highgrade isthmic spondylolisthesis. As well symptoms may vary depending the age of patient. Surgical decision making and preoperative planning need to address not only the anatomic deformity but also the symptoms complex as manifested by the predominance of either back pain and/or radicular symptoms. However, the patients with high-grade isthmic spondylolisthesis are very limited in Korea. Therefore, the best reliable reduction method for high-grade spondylolisthesis remains a challenging procedure, requiring great surgical attention to detail.