L5-S1 Isthmic Spondylolisthesis Research Articles

Comparative Analysis of Three Posterior-Only Surgical Techniques for Isthmic L5-S1 Spondylolisthesis.

To compare adults with isthmic L5-S1 spondylolisthesis who were treated with three different surgical techniques: PS-only, TS, and transforaminal lumbar interbody fusion/posterior lumbar interbody fusion (TLIF/PLIF). This is a retrospective analysis of adults with L5-S1 isthmic spondylolisthesis (grade ≥2) who underwent primary all-posterior operations with pedicle screws. Patients were excluded if they had <1 year follow-up, anterior approaches, and trans-sacral fibular grafts. Patient demographics and surgical, radiographic, and clinical data were compared between groups based on the method of anterior column support: none (PS-only), TS, and TLIF/PLIF. Sixty patients met inclusion criteria (male patients 21, female patients 39, average age 47 ± 15 years, PS-only 16; TS 20; TLIF/PLIF 24). TS patients more commonly had high-grade slips and markedly greater slip percentage, lumbosacral kyphosis, and pelvic incidence. The three groups were similar for smoking status, visual analog scores/Oswestry Disability Index scores (VAS/ODI), surgical data, and average follow-up (40.1 ± 31.2 months). All groups had similarly notable improvements in Meyerding grade and lumbosacral angle. Slip reduction percentage was similar between groups. While there was a markedly higher overall complication rate for PS-only constructs, all groups had similarly notable improvements in ODI and VAS back scores. All-posterior techniques for L5-S1 isthmic spondylolisthesis resulted in excellent improvement in preoperative symptoms and HRQoL scores and similar radiographic alignment. Trans-sacral screws were more commonly used for high-grade slips. The use of anterior column support resulted in fewer overall complications than posterior-only instrumentation.

Should adjacent asymptomatic lumbar disc herniation of L5-S1 isthmic spondylolisthesis be simultaneously rectified? Evaluation of postoperative spino-pelvic sagittal balance and functional outcomes

BackgroundThis study aimed to analyze the efficacy of the simultaneous rectification of adjacent asymptomatic lumbar disc herniation (asLDH) of L5-S1 isthmic spondylolisthesis (IS).MethodsOne hundred and forty-eight patients with L5-S1 IS, and simultaneous L4-5 asLDH, were recruited between January 2012 and December 2017, for this study. Group A: seventy-two patients received PLIF at L5-S1. Group B: seventy-six patients received PLIF at L4-S1. The radiographic outcomes were assessed via the lumbar lordosis (LL), segmental lordosis (SL), sacral slope (SS), pelvic incidence (PI), pelvic tilt (PT), PI-LL and slip degree (SD). The functional outcomes were evaluated via the visual analog scale (VAS), Oswestry disability index (ODI), and reoperation rate. The potential risk hazards for reoperation were identified using both uni- and multivariate logistic regression analyses.ResultsThe postoperative LL, SL, PT, SS, SD, VAS, and ODI exhibited vast improvements (P < 0.05). Relative to Group A, Group B exhibited markedly better LL, SL, PT, PI-LL,VAS and ODI scores at the final follow-up (P < 0.05). Group B also achieved better SD values post surgery than Group A (P < 0.05). The reoperation rate was remarkably elevated in Group A, compared to Group B (P < 0.05). The multivariate logistic regression analysis showed the L4-5 asLDH grade was a stand-alone risk hazard for reoperation, whereas, pre-SL and pre-LL offered protection against reoperation (P < 0.05).ConclusionsL4-S1 PLIF is recommended to correct asLDH in L5-S1 IS patients, with high-grade disc herniation and abnormal sagittal alignment.

ALIF Versus TLIF for L5-S1 Isthmic Spondylolisthesis: ALIF Demonstrates Superior Segmental and Regional Radiographic Outcomes and Clinical Improvements Across More Patient-reported Outcome Measures Domains.

Retrospective cohort study. The purpose of this study was to compare segmental and regional radiographic parameters between anterior interbody fusion (ALIF) and posterior interbody fusion (TLIF) for treatment of L5-S1 isthmic spondylolisthesis, and to assess for changes in these parameters over time. Secondarily, we sought to compare clinical outcomes via patient-reported outcome measures (PROMs) between techniques and within groups over time. Isthmic spondylolistheses are frequently treated with interbody fusion via ALIF or TLIF approaches. Robust comparisons of radiographic and clinical outcomes are lacking. We reviewed pre- and postoperative radiographs as well as Patient-Reported Outcomes Measurement Information System (PROMIS) elements for patients who received L5-S1 interbody fusions for isthmic spondylolisthesis in the Mass General Brigham (MGB) health system (2016-2020). Intraclass correlation testing was used for reliability assessments; Mann-Whitney U tests and Sign tests were employed for intercohort and intracohort comparative analyses, respectively. ALIFs generated greater segmental and L4-S1 lordosis than TLIF, both at first postoperative visit (mean 26 days [SE = 4]; 11.3° vs. 1.3°, P < 0.001; 6.2° vs. 0.3°, P = 0.005) and at final follow-up (mean 410days [SE = 45]; 9.6° vs. 0.2°, P < 0.001; 7.9° vs. 2.1°, P = 0.005). ALIF also demonstrated greater increase in disc height than TLIF at first (9.6 vs. 5.5 mm, P < 0.001) and final follow-up (8.7 vs. 3.6 mm, P < 0.001). Disc height was maintained in the ALIF group but decreased over time in the TLIF cohort (ALIF 9.6 vs. 8.7 mm, P = 0.1; TLIF 5.5 vs. 3.6 mm, P < 0.001). Both groups demonstrated improvements in Pain Intensity and Pain Interference scores; ALIF patients also improved in Physical Function and Global Health - Physical domains. ALIF generates greater segmental lordosis, regional lordosis, and restoration of disc height compared to TLIF for treatment of isthmic spondylolisthesis. Additionally, ALIF patients demonstrate significant improvements across more PROMs domains relative to TLIF patients.Level of Evidence: 3.

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.

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

IntroductionSurgical management of isthmic spondylolisthesis is controversial and reports on anterior approaches in the literature are scarce. Research questionTo 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 methodsAll 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. Results34 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 conclusionAfter 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.

Use of L5-S1 transdiscal screws in the treatment of isthmic spondylolisthesis: a technical note.

Surgical treatment of L5-S1 isthmic spondylolisthesis consists of a combination of decompression and fusion. One previously discussed mode of fusion is via transdiscal screws. Biomechanical studies of transdiscal screws have demonstrated greater rigidity than traditional pedicle screw fixation, which theoretically translates to a higher fusion rate. Furthermore, when compared to pedicle screw fixation, transdiscal screw fixation also demonstrates improved functional and radiographic outcomes. However, transdiscal screw placement can be technically difficult. At this time, a detailed surgical technique has yet to be reported in the literature. Our surgical technique for transdiscal screw placement using intraoperative C-arm at L5-S1 is described. We include considerations for preoperative planning including necessary imaging and appropriate patient selection. We also discuss intraoperative concerns such as setup, surgical approach, proper screw trajectory, and our method for achieving indirect decompression. The results of thirteen consecutive patients treated with transdiscal screw fixation are described. One patient had subcutaneous seroma requiring reoperation (7.7%), three patients had implant failure (23.1%), and one patient had nonunion (7.7%). Our results suggest that transdiscal screw fixation is a safe and acceptable alternative for stabilization and indirect decompression of L5-S1 isthmic spondylolisthesis. Recent innovation in intraoperative navigation and robotic surgery may lessen the technical difficulty of transdiscal screw placement and make it even more effective.

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

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. 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. 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. 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. 2. 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.

What is the difference in pedicle morphology of the fifth lumbar vertebra between isthmic and degenerative L5-S1 spondylolisthesis? An anatomic study of 328 patients via multi-slice spiral computed tomography.

The purpose of this study was to investigate and determine whether there are differences in L5 pedicles morphology between isthmic and degenerative L5-S1 spondylolisthesis. One hundred and nineteen patients with isthmic spondylolisthesis and 45 patients with degenerative spondylolisthesis at L5-S1 were enrolled in the IS group and DS group, respectively, and 164 lumbar disc herniation patients without spondylolysis or spondylolisthesis were classified into the normal (NL) group. A series of pedicle parameters of the fifth lumbar vertebra, including pedicle length (PL), pedicle width (PW), pedicle screw trajectory length (PSTL), pedicle height (PH), and the pedicle camber angle (PCA), were measured using multi-slice spiral computed tomography (MSCT). The slip distance of the L5 vertebra was measured on radiography, and the percentage of slip was also recorded. The pedicles of the fifth lumbar vertebra were shorter and wider, and the PCA was larger in the IS group compared to the DS group and NL group. On the contrary, the pedicles in the DS group were elongated and thinner, and the PCA was smaller. The pedicle parameters of PL were significantly positively correlated with the percentage of slip in the DS group, but PW and PCA were negatively correlated with the percentage of slip. There was no correlation between the percentage of slip and L5 pedicle parameters in the IS group. The L5 pedicles morphology in L5-S1 isthmic spondylolisthesis shows abduction, shortness, and width, while that in the degenerative spondylolisthesis shows adduction, lengthening, and thinning compared with the normal populations. The morphology changes may be the result of pedicle stress remodelling in the development of spondylolisthesis, which should be taken into consideration when placing at the insertion of pedicle screws.

Lumbar Pedicle Morphology and Vertebral Dimensions in Isthmic and Degenerative Spondylolisthesis-A Comparative Study.

The pedicle screw is the most common device used to achieve fixation in fusion of spondylolistheses. Safe and accurate placement with this technique relies on a thorough understanding of the bony anatomy. There is a paucity of literature comparing the surgically relevant osseous anatomy in patients with a degenerative spondylolisthesis (DS) and an isthmic spondylolisthesis (IS). The goal of this study was to determine the differences in the osseous anatomy in patients with a DS and those with an IS. A retrospective comparative cohort study was conducted on patients with a single-level, symptomatic L4-L5 DS or a single-level, symptomatic L5-S1 IS. Magnetic resonance imaging for these patients was reviewed. Morphometries of the pedicle and vertebral body were analyzed by 2 independent observers for the levels from L3 to S1, and radiographic parameters were compared between groups. A total of 572 levels in 143 patients were studied, including 103 patients with a DS and 40 with an IS. After accounting for confounders, IS and DS had an independent effect on transverse vertebral body width, pedicle height and width, and sagittal pedicle angle. Patients with an IS had a smaller pedicle height (P < .001) and pedicle width (P = .001) than patients with DS. In addition, the angulation of the pedicles varied on the basis of the diagnosis. The osseous anatomy is significantly different in patients with a DS than with an IS. Patients with an IS have smaller pedicles in the lumbar spine. Also, the L4 and L5 pedicles are more caudally angulated and the S1 pedicle is less medialized. 3. Understanding the differences in pedicle anatomy is important for the safe placement of pedicle screws.

Iliocava junction to L4-L5 disc anatomical relationship in L5-S1 isthmic spondylolisthesis

BackgroundAnterior lumbar interbody fusion finds a place in L5-S1 isthmic spondylolisthesis (ISPL) treatment. Extension of this arthrodesis at L4-L5 level is sometimes required. Anterior approach of the L4L5 disc is considered difficult due to the anatomical relationship between the iliocava junction (ICJ) and the spine. HypothesisDoes the lumbosacral deformation induced by ISPL allows anterior approach of L4-L5 disc between the iliac? Study designRetrospective radiographic analysis of consecutive patients. MethodsThis retrospective imaging study of a continuous series of 97 patients treated for an L5-S1 ISPL involved radiological parameters specific to ISPL and pelvic-sagittal balance. The distance between the ICJ and the L4 lower endplate was measured in millimeters. The factors influencing this distance were sought in order to identify a predictive model of high ICJ. ResultsThe ICJ took a cranial position with respect to the L4-L5 disc with an average distance of 1.8mm±16.4. This distance was statistically higher in the case of high-grade ISPL (p<0.01). The high ICJ position was correlated with a high Taillard index (r=0.39; CI95% [0.13; 0.61]; p<.001) and a low lumbar-sacral angle (LSA) (r=−0.33; CI95% [−0.56; −0.06]; p<0.01). Among the parameters specific to spino-pelvic statics, pelvic incidence, pelvic tilt and lumbar lordosis had similar correlations (r>0.30). ConclusionISPL induces a geometric deformation of the lumbosacral hinge which modifies its anatomical relations with the ICJ. The anterior approach technique of L4-L5 disc in the presence of an L5-S1 ISPL is possible between the iliac veins for the large displacement and low LSA forms. Level of evidenceIV, retrospective analysis.

High grade isthmic spondylolisthesis; can reduction always re-align the unbalanced pelvis?

BackgroundRecently, various studies have reported the importance of distinguishing between balanced and unbalanced SL, sustaining the importance of SL reduction in unbalanced cases. In this study we present our experience in the treatment of isthmic spondylolisthesis in young patients, observing the correlation between SL reduction and sagittal correlation between spine and pelvis.MethodsThis is a retrospective study of a series of patients treated surgically for isthmic spondylolisthesis. Inclusion criteria were L5-S1 isthmic spondylolisthesis of III° or IV°, pediatric age, clinical and radiographic follow up of at least 1 year. Radiographic evaluation included the following elements: grade and percentage of listhesis (%L), lumbar lordosis (LL), lumbar-sacral angle (LSA), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT) distinguishing between “balanced” and “unbalanced” patients. Radiographic values were confronted by using Student’s t- test, obtaining a statistically significant difference for values inferior to 0,05.ResultsBased on inclusion criteria, 28 patients were selected for our retrospective analysis, 19 female and 9 male. Mean age at surgery was 15,6 years. Mean follow up was 3 years and 3 months (min. 1 year – max 6 years and 7 months). Spondylolisthesis reduction was statistically significant both in balanced and in unbalanced patients, but pelvic incidence values did not improve significantly. We observed fewer mechanical complications in patients treated with interbody support.ConclusionIn our study, differences between pre-op and post-op spinopelvic alignment values were not statistically significant, even though spondylolisthesis reduction was statistically significant in all cases. Our study could be considered an initial attempt to correlate spinopelvic changes to spondylolisthesis reduction in a progressive manner, and possibly in the future, generate threshold values of reduction for ideal spinopelvic alignment in every different patient.

197. Prevalence of isthmic and degenerative lumbar spondylolisthesis: analysis of 882 CT scans

BACKGROUND CONTEXT Lumbar isthmic spondylolisthesis has been reported to occur in 4% to 6% of the population. The prevalence of L5-S1 degenerative spondylolisthesis has not been reported to date. Large series evaluating prevalence of congenital or degenerative conditions of the lumbar spine are needed in order to advise patients in clinical practice and to guide future research questions. PURPOSE To evaluate the prevalence of isthmic and degenerative spondylolisthesis in patients undergoing abdominal/pelvic CT scans. STUDY DESIGN/SETTING Observational study. PATIENT SAMPLE Patients undergoing CT scans of the abdomen and pelvis at a Level I trauma center in January 2017. OUTCOME MEASURES Presence or absence of isthmic/degenerative spondylolisthesis. METHODS Patients undergoing CT scans of the abdomen and pelvis at a Level I trauma center in January 2017 were enrolled. Inclusion criteria included complete CT scans (axial sagittal, coronal). The following variables were collected: age, sex, race/ethnicity as well as the presence of L3-L4, L4-L5, L5-S1 isthmic spondylolisthesis and the presence of L3-L4, L4-L5, L5-S1 degenerative spondylolisthesis. RESULTS One thousand CT scans were available and 882 patients met our inclusion criteria: 440 F (49.9%) and 442 M with an average age of 57.1 (SD 18.8). Ethnicities represented was 1.1% Asian-Americans, 14.3% African-Americans, 83.7% Caucasians and 4% Hispanic. The prevalence of isthmic spondylolisthesis was 6.8%; L3-L4 (0.9%), L4-L5 (2.2%), L5-S1 (3.7%). The prevalence of degenerative spondylolisthesis was 24.8%; L3-L4 (4.5%), L4-L5 (12%), L5-S1 (8.3%). CONCLUSIONS In one of the largest series evaluating the prevalence of isthmic and degenerative lumbar spondylolisthesis, we have identified the prevalence of L5-S1 isthmic spondylolisthesis to be 3.7%. The prevalence of L5-S1 degenerative spondylolisthesis has not been described to date and has a prevalence of 8.3%. Overall, L4-L5 had the highest prevalence of degenerative spondylolisthesis at 12%. This study can guide patient care by providing prevalence information and can guide future research on rarely described conditions such as L5-S1 degenerative spondylolisthesis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Lumbar isthmic spondylolisthesis has been reported to occur in 4% to 6% of the population. The prevalence of L5-S1 degenerative spondylolisthesis has not been reported to date. Large series evaluating prevalence of congenital or degenerative conditions of the lumbar spine are needed in order to advise patients in clinical practice and to guide future research questions. To evaluate the prevalence of isthmic and degenerative spondylolisthesis in patients undergoing abdominal/pelvic CT scans. Observational study. Patients undergoing CT scans of the abdomen and pelvis at a Level I trauma center in January 2017. Presence or absence of isthmic/degenerative spondylolisthesis. Patients undergoing CT scans of the abdomen and pelvis at a Level I trauma center in January 2017 were enrolled. Inclusion criteria included complete CT scans (axial sagittal, coronal). The following variables were collected: age, sex, race/ethnicity as well as the presence of L3-L4, L4-L5, L5-S1 isthmic spondylolisthesis and the presence of L3-L4, L4-L5, L5-S1 degenerative spondylolisthesis. One thousand CT scans were available and 882 patients met our inclusion criteria: 440 F (49.9%) and 442 M with an average age of 57.1 (SD 18.8). Ethnicities represented was 1.1% Asian-Americans, 14.3% African-Americans, 83.7% Caucasians and 4% Hispanic. The prevalence of isthmic spondylolisthesis was 6.8%; L3-L4 (0.9%), L4-L5 (2.2%), L5-S1 (3.7%). The prevalence of degenerative spondylolisthesis was 24.8%; L3-L4 (4.5%), L4-L5 (12%), L5-S1 (8.3%). In one of the largest series evaluating the prevalence of isthmic and degenerative lumbar spondylolisthesis, we have identified the prevalence of L5-S1 isthmic spondylolisthesis to be 3.7%. The prevalence of L5-S1 degenerative spondylolisthesis has not been described to date and has a prevalence of 8.3%. Overall, L4-L5 had the highest prevalence of degenerative spondylolisthesis at 12%. This study can guide patient care by providing prevalence information and can guide future research on rarely described conditions such as L5-S1 degenerative spondylolisthesis.

Comparison of sagittal plane morphology of spine and pelvis in adolescents with L₅S₁ developmental spondylolisthesis and isthmic spondylolisthesis

To compare the sagittal morphological features of the spine and pelvis between L₅S₁ dysplastic spondylolisthesis and isthmus spondylolisthesis in adolescent. Retrospective analysis of 24 cases of adolescent L₅S₁ spondylolisthesis with complete imaging data from May 2002 to December 2016. Those included 8 males and 16 females, aged from 10 to 18 years old with an average of (13.4±2.0) years. Among them, 9 cases were diagnosed as dysplastic spondylolisthesis (dysplasia group) and 15 cases isthmic spondylolisthesis (ischemic group). Radiographic parameters including slippage distance, slippage degree, slippage angle, sagittal vertical axis(SVA), thoracic kyphosis(TK), lumbar lordosis(LL), L₅ incidence(L₅I), pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS), sagittal pelvic thickness(SPT), lumbosacral angle (LSA), sacral table angle (STA) were measured on the spinal lateral X-ray of the standing position. Independent-samples t-test was used in the comparison of each variable between two groups. P<0.05 was considered statistically significant. There were no significant differences in slippage distance, slippage rate, slippage angle between two groups. In dysplasia group, SVA, L₅I, PT, SPT were (37.0±48.4) mm, (57.0±14.8)°, (42.3±15.4)°, (56.1±21.2) mm, respectively, and (-11.0±22.2) mm, (31.7±19.3) °, ( 15.5±10.2)°, (31.4±19.1) mm in ischemic group; and the differences between the two groups were significant(P<0.05). In ischemic group, SS, LSA, STA were (44.1±12.6)°, (103.9±21.7)°, (92.7±9.9)°, respectively, and (25.9±20.2) °, (75.4±16.4) °, (75.4±9.7) ° in dysplasia group; and the differences between the two groups were significant(P<0.05). There was no significant difference in TK, LL between two groups(P>0.05). Significant different from isthmic spondylolisthesis, adolescents with dysplastic spondylolisthesis present a different spino-pelvic sagittal alignment, characterized with trunk forward leaning and pelvic retroversion. In case of sagittal imbalance, early surgical intervention is required to restore a balanced spino-pelvic alignment.

Circumferential fusion: a comparative analysis between anterior lumbar interbody fusion with posterior pedicle screw fixation and transforaminal lumbar interbody fusion for L5–S1 isthmic spondylolisthesis

Background ContextTransforaminal lumbar interbody fusion (TLIF) or anterior lumbar interbody fusion with percutaneous pedicle screws (ALIFPS) offer significantly higher radiographic fusion rates than other fusion techniques for L5–S1 isthmic spondylolisthesis (IS). As it stands, there is a relative paucity of comparative data of the two techniques. PurposeTo define the clinical, radiographic, and financial differences between TLIF and ALIFPS for L5–S1 IS. Design/SettingA retrospective cohort study conducted at a single tertiary care center. Patient SampleSixty-six patients who underwent either TLIF or ALIPFS for L5–S1 IS at a single tertiary care center between 2009 and 2014. Outcome MeasuresQuality of life outcome scores including the EuroQol-5 Dimensions (EQ-5D), Pain Disability Questionnaire (PDQ), and Patient Health Questionnaire-9 (PHQ-9). Sagittal balance parameters including: pelvic incidence, pelvic tilt, sacral slope, segmental lordosis, total lordosis, degree of slip, disc height, and L1-axis S1 distance (LASD). Cost measures included in-hospital charges, hospital length of stay (LOS), and post-admission costs accrued over 1 year. MethodsQuality of life (QoL) outcome scores, radiographic data, and financial data were collected with a minimum of 1-year follow-up. Clinical results were investigated using the PDQ, PHQ-9, and EQ-5D. Radiographic measurements included lumbar lordosis, segmental lordosis, pelvic tilt, pelvic incidence, height of disc, L-1 axis S-1 distance, and the degree of slip. Cost data were generated based on patient-level resource utilization. Comparative data were presented as median with interquartile range (IQR). Continuous variables were compared using either independent Student t tests assuming unequal variance or Mann-Whitney U tests for parametric and nonparametric variables, respectively. The minimally clinical important difference (MCID) used for each questionnaire was as follows: PDQ (26), PHQ-9 (5), and EQ-5D (0.4). ResultsA total of 66 patients met inclusion criteria. In the ALIFPS cohort, PDQ scores improved from 69 [47, 82] to 26 [18.2, 79.7], p=.02. In the TLIF cohort, PDQ scores improved from 73 [46, 85] to 48.5 [23, 67.5], p=.01. Both groups also showed a significant improvement in EQ-5D scores at 1 year, but the ALIFPS group showed a significantly greater improvement in EQ-5D scores at 1 year (0.1 [0,0.2] vs. 0.2 [0.1, 0.4], p=.02). Furthermore, only the ALIFPS cohort showed a significant improvement in segmental lordosis. The ALIFPS cohort showed a significantly greater improvement in disc height than did TLIF (3.5 [2, 5.5] vs. 6.7 [4.1, 10], p=.01). No significant differences were found in the direct costs of both procedures. ConclusionsOur findings suggest that anterior lumbar interbody fusion with percutaneous pedicle screws can achieve better clinical outcomes compared with TLIF for the treatment of IS. We believe the superior radiographic outcomes achieved through ALIFPS, namely a greater restoration of segmental lordosis and disc height, may have contributed to the improved clinical outcomes presented in the current study.

The Role of the Features of Facet Joint Angle in the Development of Isthmic Spondylolisthesis in Young Male Patients with L5-S1 Isthmic Spondylolisthesis.

To investigate facet tropism and its role in development of lumbar isthmic spondylolisthesis (IS) in young men. From March 2013 to May 2016, bilateral facet joint angles were measured axially at L3-4, L4-5, and L5-S1 on lumbar computed tomography (CT) in 97 participants (46patients with IS and 51 control subjects) 20-29 years old. A difference between the 2 corresponding facet angles of <6° was classified as no tropism; a difference of 6°-12°, moderate tropism; and a difference of >12°, severe tropism. We measured 276 facet angles from 46 patients with IS and 306 facet angles from 51 control subjects. For patients with IS, there was no tropism in 43.5% (n= 20), moderate tropism in 50% (n= 23), and severe tropism in 6.5% (n= 3) at L3-4. For L4-5, there was no tropism in 28.3% (n= 13), moderate tropism in 60.9% (n= 28), and severe tropism in 10.9% (n= 5). For L5-S1, there was no tropism in 32.6% (n= 15), moderate tropism in 39.1% (n= 18), and severe tropism in 28.3% (n= 13). For the control group, there was no tropism in 86.3% (n= 44), moderate tropism in 13.7% (n= 7), and no severe tropism at L3-4. For L4-5, there was no tropism in 80.4% (n= 41), moderate tropism in 17.6% (n= 9), and severe tropism in 1.9% (n= 1). For L5-S1, there was no tropism in 68.6% (n= 35), moderate tropism in 29.4% (n= 15), and severe tropism in 1.9% (n= 1). Facet angle tropism is seen in a high proportion of patients with IS and seems to be a predisposing factor in the etiology of IS.

Une série continue de 27 patients adultes opérés d’un spondylolisthésis isthmique L5-S1 par voie combinée : résultats cliniques et radiologiques à 1 an de suivi

Through this single-center consecutive prospective study, we evaluated the results of a combined approach for L5-S1 isthmic spondylolisthesis, using a polyetheretherketone (PEEK) interbody lordotic cage during anterior approach and pedicle screw-based posterior fixation. Between 2010 and 2014, 27 adult patients were treated for L5-S1 isthmic spondylolisthesis (high and low grades) by a combined approach with a minimum follow-up of one year. Clinical outcome was assessed before surgical treatment and at four months and one year after surgery by: VAS, Oswestry Index (ODI) and Rolland-Morris scores. Two observers evaluated the following radiological parameters: pelvic incidence, pelvic tilt, lumbar lordosis, segmental lordosis L5-S1, anterior and posterior disc height, spinal vertical axis (SVA), SVA/sacro-femoral distance (SFD) ratio. Fusion was evaluated on the CT scan at one-year follow-up. Blood loss, surgery time and complications were also collected. The mean age was 47.7 years (±16.9). The VAS, ODI and Rolland-Morris scores were significantly improved postoperatively, decreased from 7.5 (±1.45); 48 (±19.25); 15.3 (±4.67) before the surgery to 3.8 (±2.55); 28.7 (±19.58) and 7.76 (±7.21) respectively at one year after the surgery (P=0.05). The mean follow-up was 3.3 years. Mean surgery time was 193.7min (±37). Fusion was obtained in 100% of cases. Segmental lordosis L5-S1, pelvic tilt, slippage, anterior and posterior L5-S1 disc height were significantly improved postoperatively, they passed from 20.1; 22.6; 35.3%; 26.4%; 17.9% to 29.5; 20.6; 20.3%; 64.4%; 36.3% respectively. Combined surgical procedure meets the required goals of surgery in the treatment of adults L5-S1 isthmic spondylolisthesis.

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.

To evaluate the incidence and course of iatrogenic L5 radiculopathy after reduction and instrumented fusion of high-grade L5-S1 isthmic spondylolisthesis and the role of intraoperative neurophysiological monitoring (IONM). Consecutive patients treated for high-grade spondylolisthesis with IONM from 2005 to 2013 were screened for eligibility. Prospectively collected clinical and surgical data as well as radiographic outcomes were analyzed retrospectively. Patients completed the multidimensional Core Outcome Measures Index (COMI) before and at 3, 12, and 24months after surgery. Seventeen patients were included, with a mean age of 26.3 (±9.5) years. Mean preoperative L5-S1 slip was 72% (±21%) and was reduced to 19% (±13%) postoperatively. Mean loss of reduction at last follow-up [mean 19months (±14, range 3-48months)] was 3% (±4.3%). Rate of new L5 radiculopathy with motor deficit (L5MD) after surgery was 29% (five patients). Four patients fully recovered after 3months, one patient was lost to neurologic follow-up. IONM sensitivity and specificity for postoperative L5MD was 20 and 100%, respectively. COMI, back pain and leg pain scores showed significant (p<0.001) improvements at 3months postoperatively, which were retained up to 24months postoperatively. Transient L5 radiculopathy after reduction and instrumented fusion of high-grade spondylolisthesis is frequent. With IONM the risk of irreversible L5 radiculopathy is minimal. If IONM signal changes recover, full clinical recovery is expected within 3months. Overall, patient-reported outcome of reduction and instrumented fusion of high-grade spondylolisthesis showed clinically important improvement.

Transdiscal screw versus pedicle screw fixation for high-grade L5-S1 isthmic spondylolisthesis in patients younger than 60years: a case-control study.

To compare outcomes between transdiscal and conventional pedicle fixation for high-grade L5-S1 spondylolisthesis. This was a retrospective case-control study with patients prospectively followed. Twenty-five consecutive patients with mean age of 36.7years underwent transdiscal fixation, and 31 other with mean age of 42.0years to pedicle fixation were clinically and radiographically compared. Clinical assessments were performed using Oswestry Disability Index (ODI), Core Outcomes Measures Index (COMI), Short-Form 12 (SF-12), and pain visual analog scale (VAS). Radiographic spinopelvic parameters were also evaluated. The mean follow-up was 2.7years (range 2.0-5.3). Preoperative data were comparable between groups. Surgery time, blood loss, and hospital stay were similar between groups. At last follow-up, clinical and radiographic outcomes were significantly improved in both groups. Postoperatively, both lumbar and leg pain VAS were similar between groups, but ODI (20.2 vs. 31.6, p=0.010), COMI (1.6 vs. 2.8, p=0.012), and SF-12 physical (84.3 vs. 61.5, p=0.004) and mental (81.5 vs. 69.4, p=0.021) scores were significantly better in the transdiscal group. The neurologic complication rate was similar in both groups. There were 4 pseudoarthroses in the pedicle group, and none in the transdiscal group. L5-S1 transdiscal screw fixation provided better functional and radiographic outcomes at medium-term than conventional pedicle fixation for high-grade spondylolisthesis, although transdiscal sacral screws are difficult to place in correct position.

“Reverse Bohlman” technique for the treatment of high grade spondylolisthesis in an adult population

Background/aimsSurgical techniques for effective high-grade spondylolisthesis (HGS) remain controversial. This study aims to evaluate radiographic/clinical outcomes in HGS patients treated using modified “Reverse Bohlman” (RB) technique. MethodsReview of consecutive HGS patients undergoing RB at a single university-center from 2006 to 2013. Clinical, surgical, radiographic parameters collected. ResultsSix patients identified: five with L5-S1 HGS with L4-L5 instability and one had an L4-5 isthmic spondylolisthesis and grade 1 L5-S1 isthmic spondylolisthesis. Two interbody graft failures and one L5-S1 pseudoarthrosis. Postoperative improvement of anterolisthesis (62.3% vs. 49.6%, p=0.003), slip angle (10 vs. 5°, p=0.005), and lumbar lordosis (49 vs. 57.5°, p=0.049). ConclusionsRB technique for HGS recommended when addressing adjacent level instability/slip.

Restoration of the spinopelvic sagittal balance in isthmic spondylolisthesis: posterior lumbar interbody fusion may be better than posterolateral fusion

Background contextMore and more orthopedic surgeons recognize the importance of the sagittal balance of the spine. PurposeTo analyze the pre- and postoperative sagittal and deformity parameters of low-grade isthmic spondylolisthesis and evaluate the effect of posterolateral fusion (PLF) and posterior lumbar interbody fusion (PLIF) on spinopelvic sagittal balance. Study designNonrandomized controlled prospective study with a historical control. Patient sampleA total of 99 patients with low-grade L5–S1 isthmic spondylolisthesis were treated surgically; 36 patients (mean age, 60.2±5.2 years) received the PLF operation, and 63 patients (mean age, 57.1±6.9 years) chose the PLIF operation. The healthy control group was composed of 60 volunteers (mean age, 44.5±8.4 years). Outcome measuresThe pre- and postoperative spinopelvic and deformity parameters. MethodsAll patients had radiographs that allowed measurement of spinopelvic parameters before and after the operation. All the spinopelvic and deformity parameters were measured. Two radiologists measured the parameters with the Cobb method. ResultsAll of the preoperative spinopelvic parameters showed no difference between the PLIF and PLF groups in this study (p>.05). In both of the operation groups, the preoperative pelvic incidence, pelvic tilt (PT), sacral slope, lumbar lordosis (LL), and L5 incidence (L5I) were significantly higher than in the control group (p<.01); the height of the intervertebral disc (HOD) was significantly lower than the controls. There were no significant differences in PT among PLIF, PLF, and control groups after the operation (p>.05). LL increased in the PLIF group and decreased in the PLF group. The slip degree (SD) and L5I were restored significantly in both groups. The HOD of the PLIF group increased 5.04 mm, the postoperative HOD of the PLF group had no significant change. In both PLIF and PLF groups, the correction of SD was correlated with the change of LL (r=−0.398, p=.007; r=0.365, p=.022). The restoration of HOD in the PLIF group correlated with the change of LL (r=0.334, p=.011). No significant differences could be found between the short-term clinical outcomes of the PLF and PLIF. ConclusionEither PLF or PLIF would lead a great change in spinopelvic parameters and deformity parameters. The decrease of PT may be an important role for the short-term surgical outcome. The PLIF could increase the LL and form a more reasonable sagittal alignment. From the point of the sagittal spinopelvic balance, the PLIF may be better than the PLF for patients with isthmic spondylolisthesis.