Reduction Of Spondylolisthesis Research Articles

The quest for ideal alignment: Complete reduction and fusion for high-grade spondylolisthesis

The quest for ideal alignment: Complete reduction and fusion for high-grade spondylolisthesis

High Degree Spondylolisthesis in Adults: Monosegmental Reduction and Fixation in Our Perspective

Objective: To evaluate a method to reduce high degree spondylolisthesis in adults with monosegmental fixing preserving the adjacent level and the improvement of sagittal balance. Methods: A prospective study, with 8 adult patients with high degree spondy\olisthesis (III and IV) in adults who underwent surgery by the same team. We included 5 women and 3 men with a mean age of 37 years that had no improvement with conservative treatment. The surgical technique used was total or partial reduction by Spondylolisthesis Reduction Instrument SRI System. Results: The L5-S1 level was involved in five patients, L4-L5 in two and VT-S1 in one patient. Isthmic type predominated in five patients, followed by dysplastic type in two and one a-spondytolisthesis. These patients were assessed by the Oswestry scale. Which showed a preoperative average of 59% and postoperative average of 12.4%. Conclusion: The method of high- grade spondylolisthesis reduction with instrumentation only at the affected level is a treatment option with good results, with control of the pain profile and functional improvement in patients.

Beneficial influence of single-stage posterior surgery for the treatment of lumbar brucella spondylitis combined with spondylolisthesis

We aimed to evaluate the clinical efficacy of the single-stage posterior surgical treatment for patients of lumbar brucella spondylitis combined with spondylolisthesis. In this study, we performed a retrospective analysis of 16 patients with lumbar brucellosis spondylitis combined with spondylolisthesis from January 2015 to January 2019. All patients underwent single-stage posterior lumbar debridement, reduction, interbody fusion, and instrumentation. Preoperative and postoperative of the visual analog scale (VAS), the Oswestry disability index (ODI), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were compared. In addition, the spondylolisthesis reduction rate, reduction loss rate, interbody fusion rate, and complication rate were recorded. VAS, ODI, ESR, and CRP were conducted with repeated analysis of variance data at different follow-ups. The postoperative follow-up was 12–36 months, with an average of (25.0 ± 8.1) months. VAS, ODI, ESR, and CRP were significantly better at 2-week and 1-year follow-up than preoperative results (P = 0.000, respectively). In addition, 1 year after the operation, VAS, ODI, ESR, and CRP showed a significant improvement (P = 0.000, respectively). The average spondylolisthesis reduction in 2 weeks after operation was (91.2 ± 6.7)%, and the median reduction loss rate in 1 year after operation was 8.0 (5.0, 9.8)%. At the last follow-up, all patients achieved interbody fusion, no loosening and fracture of instrumentation were found, and no recurrence happened. Single-stage posterior operation for lumbar debridement, reduction, interbody fusion, and instrumentation is beneficial for treating lumbar brucellosis spondylitis combined with spondylolisthesis. Furthermore, the reconstruction of spinal stability may relieve pain, heal lesions, and improve patients’ living.

Clinical evaluation of the efficacy of a new bone cement-injectable cannulated pedicle screw in the treatment of spondylolysis-type lumbar spondylolisthesis with osteoporosis: a retrospective study

PurposeTo investigate the clinical efficacy and safety of a bone cement-injectable cannulated pedicle screw (CICPS) in the treatment of spondylolysis-type lumbar spondylolisthesis with osteoporosis.MethodsA retrospective study was conducted on 37 patients (Dual-energy X-ray bone density detection showed different degrees of osteoporosis) with spondylolysis-type lumbar spondylolisthesis who underwent lumbar spondylolisthesis reduction and fusion using a new type of injectable bone cement screw from May 2011 to March 2015. Postoperative clinical efficacy was evaluated by the Visual Analogue Scale (VAS) scores and the Oswestry Disability Index (ODI). Imaging indexes were used to evaluate the stability of internal fixation of the devices 1, 3, 6, and 12 months after surgery and annually thereafter. The safety of the CICPS was assessed by the prevalence of intraoperative and postoperative complications.ResultsA total of 124 CICPS were implanted intraoperatively. Bone cement leakage occurred in 3 screws (2.42%), and no clinical discomfort was found in any patients. All 37 patients were followed up with an average follow-up time of 26.6 ± 13.4 months (12–58 months). In the evaluation of the clinical effects of the operation, the average postoperative VAS score of the patients decreased from 4.30 ± 1.58 before surgery to 0.30 ± 0.70 after surgery (P < 0.001), and the ODI decreased from 47.27% ± 16.97% before surgery to 3.36% ± 5.70% after surgery (P < 0.001). No screw was loose, broken or pulled out.ConclusionCICPS is safe and effective in the treatment of spondylolysis-type lumbar spondylolisthesis complicated by osteoporosis.

Short-term effectiveness of unilateral biportal endoscopic transforaminal lumbar interbody fusion for Meyerding degree Ⅰ or Ⅱ single-segment lumbar spondylolisthesis

To investigate the short-term effectiveness of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) in the treatment of Meyerding degree Ⅰ or Ⅱ single-segment lumbar spondylolisthesis. The clinical data of 26 patients with Meyerding degree Ⅰ or Ⅱ single-segment lumbar spondylolisthesis treated with UBE-TLIF between January 2021 and August 2021 were retrospectively analyzed. Among them, there were 10 males and 16 females with a mean age of 61.5 years (range, 35-76 years). The lesion segment included L 3, 4 in 2 cases, L 4, 5 in 18 cases, and L 5, S 1 in 6 cases. There were 17 cases of degenerative spondylolisthesis and 9 cases of isthmic spondylolisthesis; according to the Meyerding classification of spondylolisthesis, 19 cases were grade Ⅰ and 7 cases were grade Ⅱ. Twenty-one cases were complicated with lumbar disc herniation and spinal stenosis and 5 cases with lumbar spinal stenosis. The operation time, hospitalization stay, complications, hemoglobin (Hb) and serum creatine kinase (CK) levels before operation and at 1 day after operation were recorded; lumbar lordosis angle changes and postoperative spondylolisthesis reduction were evaluated by lumbar anteroposterior and lateral X-ray films before operation and at last follow-up; visual analogue scale (VAS) score was used to evaluate the low back pain and leg pain before operation, at 2 days, 1 week, 2 weeks after operation, and at last follow-up; Oswestry disability index (ODI) was used to evaluate the functional recovery of the patients before operation and at last follow-up. The operation was successfully completed in all 26 patients, with an average operation time of 181.9 minutes (range, 130-224 minutes) and an average hospitalization stay of 6.3 days (range, 3-9 days). Hb levels were significantly lower and serum CK levels were significantly higher at 1 day after operation when compared with those before operation ( t=7.594, P<0.001; t=-15.647, P<0.001). No serious complication occurred during and after operation. CT examination at 3 days after operation showed that the percutaneous screw was not in good position in 1 case, and nerve paralysis (pain, numbness) occurred in 2 cases after operation, which were improved within 2 weeks after operation. All the 26 patients were followed up 6-11 months, with an average of 8.7 months. Complete reduction (the slippage reduction rate was 100%) was achieved in 24 patients (92.3%), and partial reduction (the slippage reduction rate was 87.5%) in 2 patients (7.7%). During the follow-up, there was no complication such as incision infection, fusion Cage subsidence or displacement, and internal fixator loosening. The VAS scores of low back pain and leg pain significantly improved at each time point after operation when compared with those before operation ( P<0.05); there was no significant difference in the VAS scores of low back pain and leg pain between at 2 days and 1 week after operation, the VAS scores of low back pain between at 1 week and 2 weeks after operation, and the VAS scores of leg pain between at 2 weeks after operation and last follow-up ( P>0.05); but there was significant difference between the other time points after operation ( P<0.05). ODI and lumbar lordosis angle significantly improved at last follow-up ( P<0.05). UBE-TLIF provides favorable short-term effectiveness and obvious advantages of minimally invasive in the treatment of Meyerding degree Ⅰ or Ⅱ single-segment lumbar spondylolisthesis. However, the safety and long-term effectiveness need to be further studied.

Cauda equina syndrome a rare early surgical complication in a pediatric patient with dysplastic high-grade lumbosacral spondylolisthesis: A case report

Recent literature supports the surgical reduction of high-grade spondylolisthesis, particularly with an unbalanced pelvis and spine. Drop foot is the most common neurological complication reported in the literature. Scoliosis Research Society database reported only one patient (child) with cauda equina syndrome after surgery for dysplastic high-grade lumbosacral spondylolisthesis. The lack of longitudinal clinical follow-up of that patient limited their result. There is another report of 12 cauda equina syndrome cases after in situ arthrodesis for lumbosacral spondylolisthesis. The current report is the first case in the literature of cauda equina syndrome after partial reduction of dysplastic high-grade lumbosacral spondylolisthesis in a child. The aim was to raise awareness of the possibility of this post-operative complication happening in children and the possibility of avoiding it. A child who developed a cauda equina syndrome as an early neurological complication after surgery, which recovered completely 6 weeks after revision surgery, is reported. During the revision surgery, an L5-S1 transforaminal interbody fusion was performed by insertion of polyetheretherketone cage. Bilateral anal compound muscle action potential is seen after implant removal and sacral dome resection. Using somatosensory, motor evoked potential and continuous electromyogram for both rectal and external bladder sphincters in children with high-grade lumbosacral dysplastic spondylolisthesis undergoing surgical reduction are important to prevent a devastating neurological complication. Sacral dome resection and appropriate L5-S1 discectomy prevent stretching of the cauda equina over the posterosuperior border of the sacrum postoperatively.

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.

Postoperative spinal alignment comparison of lateral versus supine patient position L5-S1 anterior lumbar interbody fusion.

Over the past decade, alternative patient positions for the treatment of the anterior lumbar spine have been explored in an effort to maximize the benefits of direct anterior column access while minimizing the inefficiencies of single or multiple intraoperative patient repositionings. The lateral technique allows for access from L1 to L5 through a retroperitoneal, muscle-splitting, transpsoas approach with placement of a large intervertebral spacer than can reliably improve segmental lordosis, though its inability to be used at L5-S1 limits its overall adoption, as L5-S1 is one of the most common levels treated and where high levels of lordosis are optimal. Recent developments in instrumentation and techniques for lateral-position treatment of the L5-S1 level with a modified anterior lumbar interbody fusion (ALIF) approach have expanded the lateral position to L5-S1, though the positional effect on L5-S1 lordosis is heretofore unreported. The purpose of this study was to compare local and regional alignment differences between ALIFs performed with the patient in the lateral (L-ALIF) versus supine position (S-ALIF). Retrospective, multi-center data and radiographs were collected from 476 consecutive patients who underwent L5-S1 L-ALIF (n = 316) or S-ALIF (n = 160) for degenerative lumbar conditions. Patients treated at L4-5 and above with other single-position interbody fusion and posterior fixation techniques were included in the analysis. Baseline patient characteristics were similar between the groups, though L-ALIF patients were slightly older (58 vs. 54years), with a greater preoperative mean L5-S1 disk height (7.8 vs. 5.8mm), and with less preoperative slip (6.6 vs. 8.5mm), respectively. 262 patients were treated with only L-ALIF or S-ALIF at L5-S1 while the remaining 214 patients were treated with either L-ALIF or S-ALIF at L5-S1 along with fusions at other thoracolumbar levels. Lumbar lordosis (LL), L5-S1 segmental lordosis, L5-S1 disk space height, and slip reduction in L5-S1 spondylolisthesis were measured on preoperative and postoperative lateral X-ray images. LL was only compared between single-level ALIFs, given the variability of other procedures performed at the levels above L5-S1. Mean pre- to postoperative L5-S1 segmental lordosis improved 39% (6.6°) and 31% (4.9°) in the L-ALIF and S-ALIF groups, respectively (p = 0.063). Mean L5-S1 disk height increased by 6.5mm (89%) in the L-ALIF and 6.4mm (110%) in the S-ALIF cohorts, (p = 0.650). Spondylolisthesis, in those patients with a preoperative slip, average reduction in the L-ALIF group was 1.5mm and 2.2mm in the S-ALIF group (p = 0.175). In patients treated only at L5-S1 with ALIF, mean segmental alignment improved significantly more in the L-ALIF compared to the S-ALIF cohort (7.8 vs. 5.4°, p = 0.035), while lumbar lordosis increased 4.1° and 3.6° in the respective groups (p = 0.648). Use of the lateral patient position for L5-S1 ALIF, compared to traditional supine L5-S1 ALIF, resulted in at least equivalent alignment and radiographic outcomes, with significantly greater improvement in segmental lordosis in patients treated only at L5-S1. These data, from the largest lateral ALIF dataset reported to date, suggest that-radiographically-the lateral patient position can be considered as an alternative to traditional ALIF positional techniques.

Two different techniques combined with MIS-TLIF in the treatment of degenerative lumbar spondylolisthesis:a case-control study

To analyze the difference in clinical efficacy of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) under Quadrant channel system combined with microscope and percutaneous pedicle screw in the treatment of degenerative lumbar spondylolisthesis. A total of 114 patients with single-segment degenerative lumbar spondylolisthesis from June 2015 to February 2019, were divided into three groups according to the surgical methods, such as the MIS-TLIF under the microscope surgery group ( microscope group), MIS-TLIF combined with percutaneous pedicle screw technique surgery group(percutaneous group) and posterior lumbar interbody fusion surgery group (open group). In the microscope group, there were 12 males and 26 females, aged from 42 to 83 years with an average of (63.29±9.09) years. In the percutaneous group, there were 16 males and 22 females, aged from 45 to 82 years with an average of (63.37±7.50) years. In the open group, there were 12 males and 26 females, aged from 51 to 82 years with an average of (63.76±8.21) years. The general conditions of operation, such as operation time, intraoperative blood loss, postoperative drainage, length of surgical incision, frequency of intraoperative fluoroscopy and postoperative time of lying in bed were recorded to analyze the differences in surgical related indicators. Visual analogue scale (VAS) of waist and leg pain in preoperative and postoperative period (3 days, 3 months, 6 months and 12 months) were recorded to evaluate pain remission;Oswestry Disability Index(ODI), Japanese Orthopaedic Association (JOA) score were recorded to evaluate the recovery of waist and leg function on preoperative and postoperative 12 months. The lumbar spondylolisthesis rate and intervertebral height at 12 months after operation were recorded to evaluate the reduction of spondylolisthesis. The Siepe intervertebral fusion standard was used to analyze the intervertebral fusion rate at 12 months after operation. ①All 114 patients were followed up more than 1 year, and no complications related to incision infection occurred. In the microscope group, there was 1 case of subcutaneous effusion 8 days after operation. After percutaneous puncture and drainage, waist compression, and then the healing was delayed. In the percutaneous group, 2 cases of paravertebral muscle necrosis occurred on the side of decompression, and the healing was delayed after debridement. In open group, there was 1 case of intraoperative dural tear, which was packed with free adipose tissue during the operation. There was no postoperative cerebrospinal fluid leakage and other related complications.① Compared with microscope group, percutaneous group increased in operation time, intraoperative blood loss, postoperative wound drainage, surgical incision length, intraoperative fluoroscopy times, and postoperative bed rest time. In open group, intraoperative blood loss, postoperative wound drainage, surgical incision length, and postoperative bed rest time increased, but the intraoperative fluoroscopy time decreased. Compared with percutaneous group, the intraoperative blood loss, wound drainage, surgical incision length, and postoperative bed rest time in open group increased, but operative time and the intraoperative fluoroscopy time decreased(P<0.05). ②ODI and JOA scores of the three groups at 12 months after operation were improved compared with those before operation (P<0.05), but there was no significant difference between the three group(P>0.05). ③Compared with microscope group, the VAS of low back pain in percutaneous group increased at 3 days after operation, and VAS of low back pain in open group increased at 3 days, and 12 month after operation. Compared with percutaneous group, the VAS low back pain score of the open group increased at 3 months after operation (P<0.05). ④ The lumbar spondylolisthesis rate of the three groups of patients at 12 months afrer operation was decreased compared with that before operation(P<0.05), and the intervertebral heigh was increased compared with that before operation(P<0.05), however, there was no significant difference among three groups at 12 months afrer operation(P>0.05). ⑤ There was no significant difference between three groups in the lumbar fusion rate at 12 months afrer operation(P>0.05). The MIS-TLIF assisted by microscope and the MIS-TLIF combined with percutaneous pedicle screw are safe and effective to treat the degenerative lumbar spondylolisthesis with single-segment, and the MIS-TLIF assisted by microscope may be more invasive, cause less blood loss and achieve better clinical efficacy.

Percutaneous Endoscopic Posterior Lumbar Interbody Fusion with Unilateral Laminotomy for Bilateral Decompression Vs. Open Posterior Lumbar Interbody Fusion for the Treatment of Lumbar Spondylolisthesis.

BackgroundEndoscopic lumbar interbody fusion is a new technology that is mostly used for single-segment and unilateral lumbar spine surgery. The purpose of this study is to introduce percutaneous endoscopic posterior lumbar interbody fusion (PE-PLIF) with unilateral laminotomy for bilateral decompression (ULBD) for lumbar spondylolisthesis and evaluate the efficacy by comparing it with open posterior lumbar interbody fusion (PLIF).MethodsTwenty-eight patients were enrolled in PE-PLIF with the ULBD group and the open PLIF group. The perioperative data of the two groups were compared to evaluate the safety of PE-PLIF with ULBD. The visual analog scale (VAS) back pain, VAS leg pain, and Oswestry Disability Index (ODI) scores of the two groups preoperatively and postoperatively were compared to evaluate clinical efficacy. Preoperative and postoperative imaging data were collected to evaluate the effectiveness of the operation.ResultsNo differences in baseline data were found between the two groups (p > 0.05). The operation time in PE-PLIF with the ULBD group (221.2 ± 32.9 min) was significantly longer than that in the PLIF group (138.4 ± 25.7 min) (p < 0.05), and the estimated blood loss and postoperative hospitalization were lower than those of the PLIF group (p < 0.05). The postoperative VAS and ODI scores were significantly improved in both groups (p < 0.05), but the postoperative VAS back pain score in the PE-PLIF group was significantly lower than that in the PLIF group (p < 0.05). The excellent and good rates in both groups were 96.4% according to MacNab’s criteria. The disc height and cross-sectional area of the spinal canal were significantly improved in the two groups after surgery (p < 0.05), with no difference between the groups (p > 0.05). The fusion rates in PE-PLIF with the ULBD group and the PLIF group were 89.3% and 92.9% (p > 0.05), respectively, the cage subsidence rates were 14.3% and 17.9% (p > 0.05), respectively, and the lumbar spondylolisthesis reduction rates were 92.72 ± 6.39% and 93.54 ± 5.21%, respectively (p > 0.05).ConclusionThe results from this study indicate that ULBD can be successfully performed during PE-PLIF, and the combined procedure is a safe and reliable treatment method for lumbar spondylolisthesis.

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

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. 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. 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). 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.

Does reduction of the Meyerding grade correlate with outcomes in patients undergoing decompression and fusion for grade I degenerative lumbar spondylolisthesis?

Reduction of Meyerding grade is often performed during fusion for spondylolisthesis. Although radiographic appearance may improve, correlation with patient-reported outcomes (PROs) is rarely reported. In this study, the authors' aim was to assess the impact of spondylolisthesis reduction on 24-month PRO measures after decompression and fusion surgery for Meyerding grade I degenerative lumbar spondylolisthesis. The Quality Outcomes Database (QOD) was queried for patients undergoing posterior lumbar fusion for spondylolisthesis with a minimum 24-month follow-up, and quantitative correlation between Meyerding slippage reduction and PROs was performed. Baseline and 24-month PROs, including the Oswestry Disability Index (ODI), EQ-5D, Numeric Rating Scale (NRS)-back pain (NRS-BP), NRS-leg pain (NRS-LP), and satisfaction (North American Spine Society patient satisfaction questionnaire) scores were noted. Multivariable regression models were fitted for 24-month PROs and complications after adjusting for an array of preoperative and surgical variables. Data were analyzed for magnitude of slippage reduction and correlated with PROs. Patients were divided into two groups: < 3 mm reduction and ≥ 3 mm reduction. Of 608 patients from 12 participating sites, 206 patients with complete data were identified in the QOD and included in this study. Baseline patient demographics, comorbidities, and clinical characteristics were similarly distributed between the cohorts except for depression, listhesis magnitude, and the proportion with dynamic listhesis (which were accounted for in the multivariable analysis). One hundred four (50.5%) patients underwent lumbar decompression and fusion with slippage reduction ≥ 3 mm (mean 5.19, range 3 to 11), and 102 (49.5%) patients underwent lumbar decompression and fusion with slippage reduction < 3 mm (mean 0.41, range 2 to -2). Patients in both groups (slippage reduction ≥ 3 mm, and slippage reduction < 3 mm) reported significant improvement in all primary patient reported outcomes (all p < 0.001). There was no significant difference with regard to the PROs between patients with or without intraoperative reduction of listhesis on univariate and multivariable analyses (ODI, EQ-5D, NRS-BP, NRS-LP, or satisfaction). There was no significant difference in complications between cohorts. Significant improvement was found in terms of all PROs in patients undergoing decompression and fusion for lumbar spondylolisthesis. There was no correlation with clinical outcomes and magnitude of Meyerding slippage reduction.

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.

Expandable versus Static Transforaminal Lumbar Interbody Fusion Cages: 1-year Radiographic Parameters and Patient-Reported Outcomes

Expandable transforaminal lumbar interbody fusion (TLIF) cages capable of multidirectional in situ expansion have gained popularity as they increase axial surface area for fusion and may enhance lordotic correction through a traditional minimally invasive surgery (MIS) surgical corridor. We evaluated and compared the radiographic and clinical outcomes between a novel expandable versus static minimally invasive surgery TLIF cage for the treatment of degenerative disk disease. A single-center retrospective review of 120 consecutive adult patients undergoing 1- or 2-level MIS TLIF with an expandable (n= 60) or static cage was performed between 2015 and 2019. Preoperative and 1-year postoperative radiographic and clinical outcomes were assessed by upright flexion/extension radiographs and serial confidential surveys. One-hundred twenty patients (mean age 63.5 years, 60.0% female) undergoing 1- and 2-level MIS TLIF met inclusion criteria. A statistically significant reduction of spondylolisthesis, restoration of foraminal height as well as anterior and posterior disk height was achieved in both cohorts, however was greater in the expandable cage cohort (ECC) (all P < 0.05). Comparable rates of fusion, 93% and 91%, were observed in the ECC and static cage cohort. A significant reduction in Numeric Pain Rating Scale back and Oswestry Disability Index scores were observed in both cohorts but were more pronounced in the ECC (5.9 ± 2.4 to 2.2 ± 1.9 and 37.3 ± 16.2 to 17.1 ± 15.2) versus static cage cohort (6.2 ± 2.8 to 3.2 ± 2.5 and 41.8 ± 16.1 to 24.3 ± 17.5) (P < 0.05). One instance of cage migration requiring reoperation occurred in the ECC. Taken together, these radiographic and clinical findings suggest an expandable cage placed through an MIS corridor represents a safe, equitable, and efficacious alternative to a static TLIF in adults with degenerative lumbar pathology.

Biomechanical analysis of reduction technique for lumbar spondylolisthesis: anterior lever versus posterior lever reduction method

BackgroundReduction of lumbar spondylolisthesis during spinal fusion surgery is important for improving the fusion rate and restoring the sagittal alignment. Despite the variety of reduction methods, the fundamental mechanics of lumbar spondylolisthesis reduction remain unclear. This study aimed to investigate the biomechanical behavior while performing spondylolisthesis reduction with the anterior and posterior lever reduction method.MethodsWe developed an L4–L5 spondylolisthesis model using sawbones. Two spine surgeons performed the simulated reduction with a customized Cobb elevator. The following data were collected: the torque and angular motion of Cobb, displacement of vertebral bodies, change of lordotic angle between L4 and L5, total axial force and torque applied on the model, and force received by adjacent disc.ResultsLess torque value (116 N-cm vs. 155 N-cm) and greater angular motion (53o vs. 38o) of Cobb elevator were observed in anterior lever reduction. Moreover, the total axial force received by the entire model was greater in the posterior lever method than that in the anterior lever method (40.8 N vs. 16.38 N). Besides, the displacement of both vertebral bodies was greater in the anterior lever method.ConclusionsThe anterior lever reduction is a more effort-saving method than the posterior lever reduction method. The existing evidence supports the biomechanical advantage of the anterior reduction method, which might be one of the contributing factors to successfully treating high-grade lumbar spondylolisthesis with short-segment instrumentation.

28. Does loss of spondylolisthesis reduction impact clinical and radiographic outcomes after minimally invasive transforaminal lumbar interbody fusion?

<h3>BACKGROUND CONTEXT</h3> Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is the workhorse minimally invasive treatment for patients with degenerative lumbar stenosis and spondylolisthesis refractory to nonoperative care. While the basic tenets of surgical treatment do not differ between minimally invasive and open techniques, surgeons performing MI-TLIF are more likely to attempt reduction of spondylolisthesis in order to optimize restoration of canal dimensions due to a greater reliance on indirect decompression, which has been shown to be effective. While intraoperative reduction is often successful, postoperative loss of reduction and slip recurrence can be seen. <h3>PURPOSE</h3> To determine the rate and clinical impact of slip recurrence after MI-TLIF with expandable cage technology. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study. <h3>PATIENT SAMPLE</h3> Patients undergoing MI-TLIF for degenerative spondylolisthesis using an articulating, expandable cage <h3>OUTCOME MEASURES</h3> Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI), visual analog scale (VAS) for back/leg pain, Short Form-12 (SF-12) and PROMIS Physical Function (PF) <h3>METHODS</h3> Patients undergoing MI-TLIF for degenerative spondylolisthesis using articulating, expandable cages from 2017-2019 were retrospectively studied. Lateral radiographs were reviewed and evaluated for the presence or absence of spondylolisthesis preoperatively, intraoperatively, and at follow-up times including 2 weeks, 6 weeks, 12 weeks, 6 months and 1-year postoperatively. Spondylolisthesis was measured from the posterior inferior corner of the cephalad vertebra to the posterior superior corner of the caudal vertebral, with any measurement >1mm classified as spondylolisthesis, and Meyerding grade was noted. Intraoperative reduction was measured and loss of reduction was defined as >1mm increase in spondylolisthesis comparing follow-up imaging to intraoperative films. PROMs were recorded at the preoperative and follow-up time points. Fusion was assessed 1-year postoperatively via CT. <h3>RESULTS</h3> A total of 63 patients and 70 levels were included, with mean age 59.8 years (SD,13.8). Nineteen levels (27.1%) had complete reduction intraoperatively, 40 (57.1%) had partial reduction and 11 (15.7%) had no reduction. Of the 30 levels with loss of reduction (50.8%), 20 (66.7%) occurred by 2 weeks postoperatively and 28 (93.3%) occurred by 12 weeks postoperatively. At 6 months, there were significant differences between those who had loss of reduction and those who did not in VAS back pain (3.0 vs 0.9, p=0.017) and SF-12 PCS (41.5 vs 50.0, p=0.035), but no differences were found between the groups for any instruments at any other time points. The overall fusion rate was 89.5% (34/38) at 1 year postoperatively. There was no significant difference in fusion rate between the loss of reduction (16/18) and no loss of reduction (18/20) groups. Patients with loss of reduction had no difference in reoperation rate (1/28) compared to those without loss of reduction (2/24). <h3>CONCLUSIONS</h3> While a majority of patients demonstrated reduction intraoperatively, 51% had loss of reduction, most commonly in the acute postoperative period. There were few differences in PROMs between patients who had loss of reduction and those who did not, suggesting that radiographic loss of reduction after MI-TLIF in the setting of degenerative spondylolisthesis may not be clinically meaningful. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Transforaminal lumbar interbody fusion using a novel minimally invasive expandable interbody cage: patient-reported outcomes and radiographic parameters.

The goal of this study was to evaluate the clinical and radiographic outcomes of a novel multidirectional in situ expandable minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF) cage. A retrospective analysis of 69 consecutive patients undergoing a 1- or 2-level MIS TLIF using an expandable cage was performed over a 2-year period. Standard MIS techniques with pedicle screw fixation were used in all cases. Upright lateral dynamic flexion/extension radiographs were reviewed prior to and at 1 year after surgery. Clinical metrics included numeric rating scale for back and leg pain, Oswestry Disability Index, and the SF-12 and VR-12 physical and mental health surveys. Radiographic parameters included anterior and posterior disc height, neuroforaminal height, spondylolisthesis, segmental lordosis, lumbar lordosis, and fusion rate. A total of 69 patients representing 75 operative levels met study inclusion criteria. The mean patient age at surgery was 63.4 ± 1.2 years, with a female predominance of 51%. The average radiographic and clinical follow-ups were 372 and 368 days, respectively. A total of 63 patients (91%) underwent 1-level surgery and 6 patients (9%) underwent 2-level surgery. Significant reductions of numeric rating scale scores for back and leg pain were observed-from 6.1 ± 0.7 to 2.5 ± 0.3 (p < 0.0001) and 4.9 ± 0.6 to 1.9 ± 0.2 (p < 0.0001), respectively. A similar reduction in Oswestry Disability Index from 38.0 ± 4.6 to 20.0 ± 2.3 (p < 0.0001) was noted. Likewise, SF-12 and VR-12 scores all showed statistically significant improvement from baseline (p < 0.001). The mean anterior and posterior disc heights improved from 8.7 ± 1.0 mm to 13.4 ± 1.5 mm (p = 0.0001) and 6.5 ± 0.8 mm to 9.6 ± 1.1 mm (p = 0.0001), respectively. Neuroforaminal height improved from 17.6 ± 2.0 mm to 21.9 ± 2.5 mm (p = 0.0001). When present, spondylolisthesis was, on average, reduced from 4.3 ± 0.5 mm to 1.9 ± 0.2 mm (p = 0.0001). Lumbar lordosis improved from 47.8° ± 5.5° to 58.5° ± 6.8° (p = 0.2687), and no significant change in segmental lordosis was observed. The overall rate of radiographic fusion was 93.3% at 1 year. No perioperative complications requiring operative revision were encountered. In this series of MIS TLIFs, use of this novel interbody cage was shown to be safe and effective. Significant improvements in pain and disability were observed. Effective and durable restoration of disc height and neuroforaminal height and reduction of spondylolisthesis were obtained, with concurrent gains in lumbar lordosis. Taken together, this device offers excellent clinical and radiographic outcomes via an MIS approach.

Surgical Reduction of Spondylolisthesis During Lumbar Fusion: Are Complications Associated With Slip Correction?

This was a retrospective cohort study. The objective of this study was to quantify the rates of complication following surgical treatment for symptomatic degenerative and isthmic spondylolisthesis and to examine the association between slip reduction and complication rates. It is unclear if the degree of spondylolisthesis reduction during lumbar spine fusion in adults influences the rate of surgical complications. This is a retrospective cohort study of 1-level and 2-level adult fusion patients with degenerative or isthmic spondylolisthesis. The degree of reduction and complications were calculated, and complication rates between those with and without reduction were compared. The surgical reduction was improved by 1 Meyerding grade in 56.5% of the 140 patients included in this analysis. Of those patients, 60% had a grade 1 spondylolisthesis. In addition, 62.5% of grade 2 slips had an improvement by 1 grade. Surgical reduction during lumbar fusion did not result in a higher rate of complications compared with in situ fusion. During 1-level or 2-level lumbar fusion for degenerative or isthmic spondylolisthesis, a 1-grade reduction of the slip was achieved in 56% of patients in this retrospective case series. Reduction of the spondylolisthesis was not associated with a higher rate of complication when compared with in situ fusion. Level IV.

Predictors of indirect neural decompression in minimally invasive transpsoas lateral lumbar interbody fusion.

An advantage of lateral lumbar interbody fusion (LLIF) surgery is the indirect decompression of the neural elements that occurs because of the resulting disc height restoration, spinal realignment, and ligamentotaxis. The degree to which indirect decompression occurs varies; no method exists for effectively predicting which patients will respond. In this study, the authors identify preoperative predictive factors of indirect decompression of the central canal. The authors performed a retrospective evaluation of prospectively collected consecutive patients at a single institution who were treated with LLIF without direct decompression. Preoperative and postoperative MRI was used to grade central canal stenosis, and 3D volumetric reconstructions were used to measure changes in the central canal area (CCA). Multivariate regression was used to identify predictive variables correlated with radiographic increases in the CCA and clinically successful improvement in visual analog scale (VAS) leg pain scores. One hundred seven levels were treated in 73 patients (mean age 68 years). The CCA increased 54% from a mean of 0.96 cm2 to a mean of 1.49 cm2 (p < 0.001). Increases in anterior disc height (74%), posterior disc height (81%), right (25%) and left (22%) foraminal heights, and right (12%) and left (15%) foraminal widths, and reduction of spondylolisthesis (67%) (all p < 0.001) were noted. Multivariate evaluation of predictive variables identified that preoperative spondylolisthesis (p < 0.001), reduced posterior disc height (p = 0.004), and lower body mass index (p = 0.042) were independently associated with radiographic increase in the CCA. Thirty-two patients were treated at a single level and had moderate or severe central stenosis preoperatively. Significant improvements in Oswestry Disability Index and VAS back and leg pain scores were seen in these patients (all p < 0.05). Twenty-five (78%) patients achieved the minimum clinically important difference in VAS leg pain scores, with only 2 (6%) patients requiring direct decompression postoperatively due to persistent symptoms and stenosis. Only increased anterior disc height was predictive of clinical failure to achieve the minimum clinically important difference. LLIF successfully achieves indirect decompression of the CCA, even in patients with substantial central stenosis. Low body mass index, preoperative spondylolisthesis, and disc height collapse appear to be most predictive of successful indirect decompression. Patients with preserved disc height but severe preoperative stenosis are at higher risk of failure to improve clinically.

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

BackgroundsSurgical 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.MethodsAll 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.ResultsA 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.ConclusionsAnterior 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 evidenceIV