What are the differences in paraspinal muscle morphometry among degenerative spondylolisthesis patients, isthmic spondylolisthesis patients, and healthy individuals? A propensity score matching analysis

PURPOSE

To compare the morphometry of paraspinal muscles in patients with degenerative spondylolisthesis (DS), isthmic spondylolisthesis (IS), and healthy individuals.

METHODS

Thirty-seven pairs of DS patients were selected using propensity score matching with IS patients, while 37 healthy individuals matched for age, sex, and BMI were selected as controls. The relative cross-sectional area (rCSA), and relative functional cross-sectional area (rfCSA) of paraspinal muscles were measured, and the degree of fatty infiltration (FI) was calculated. Based on occupational differences, the patients were also divided into worker and farmer groups, and the same measurements were taken on them.

RESULTS

At the L3/L4 level, the multifidus (MF) FI was greater in the DS and IS groups than in the control group, the erector spinae (ES) rfCSA was higher in the IS group than in the DS and control groups. At the L4/L5 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS and control groups. At the L5/S1 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS group. At the L3/L4, L4/L5 level, MF rfCSA were higher in the worker group than in the farmer group (p < 0.05).

CONCLUSION

The morphological changes in paraspinal muscles in patients with DS were dominated by selective atrophy of the MF, while in patients with IS, the morphological changes in paraspinal muscle showed selective atrophy of the MF accompanied by compensatory hypertrophy of the ES. The surgeon should consider the morphological differences in paraspinal muscle between different types of lumbar spondylolisthesis when establishing the appropriate surgical program.

Fusion and clinical outcomes of lumbar interbody fusion for low-grade isthmic spondylolisthesis

INTRODUCTION

Low-grade isthmic spondylolisthesis (ISPL) is generally treated by circumferential fusion with interbody graft, although there is no consensus on technique.

HYPOTHESIS

The various interbody fusion strategies provide satisfactory fusion rates and clinical results.

METHODS

A multicenter retrospective study analyzed lumbar interbody fusion for low-grade ISPL performed between March 2016 and March 2019. Techniques comprised: circumferential fusion on a posterior or a transforaminal approach (PLIF, TLIF: n=57), combined anterior (ALIF)+posterolateral fusion (ALIF+PLF: n=60), and ALIF+percutaneous posterior fixation (ALIF+PPF: n=55). Function was assessed on a lumbar and a radicular visual analog scale (AVS-L, VAS-R), Oswestry Disability Index (ODI) and Short Form 12 (SF12).

RESULTS

Among the 129 patients, 85.3% showed fusion (Lenke 1 or 2), with no significant differences between the ALIF-PLF or ALIF-PPF groups and the PLIF or TLIF groups (p=0.3). Likewise, there was no difference in fusion rates between the ALIF-PPF and ALIF-PLF subgroups (p=0.28). VAS-L (p<0.001) and VAS-R (p<0.0001), ODI (p<0.001) and SF12 physical (PCS) (p<0.01) and mental component sores (MCS) (p<0.001) all showed significant improvement at 12months. Combined approaches provided greater clinical efficacy than TLIF or PLIF for lumbar (p<0.0001) and radicular pain (p<0.05), ODI (p<0.0001) and SF12 PCS (p<0.01). At 12months, there was no clinical difference between the ALIF-PPF and ALIF-PLF subgroups. However, patents with interbody non-union (Lenke 3 or 4) had lower SF12 PCS scores (p<0.004) and VAS-L ratings (p<0.001) than Lenke 1-2 patients.

CONCLUSION

Low-grade ISPL treated by circumferential arthrodesis and interbody graft showed 85.3% consolidation at 2years, with equivalent outcomes between anterior and posterior techniques. Successful fusion was associated with better clinical results.

LEVEL OF EVIDENCE

IV.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

CLINICALTRIALS

gov Identifier: NCT03644407.

Projected lifetime cancer risk for patients undergoing spine surgery for isthmic spondylolisthesis

BACKGROUND CONTEXT

Radiographs, fluoroscopy, and computed tomography (CT) are increasingly utilized in the diagnosis and management of various spine pathologies. Such modalities utilize ionizing radiation, a known cause of carcinogenesis. While the radiation doses such studies confer has been investigated previously, it is less clear how such doses translate to projected cancer risks, which may be a more interpretable metric.

PURPOSE

(1) Calculate the lifetime cancer risk and the relative contributions of preference-sensitive selection of imaging modalities associated with the surgical management of a common spine pathology, isthmic spondylolisthesis (IS); (2) Investigate whether the use of intraoperative CT, which is being more pervasively adopted, increases the risk of cancer.

STUDY DESIGN/SETTING

Retrospective cross-sectional study carried out within a large integrated health care network.

PATIENT SAMPLE

Adult patients who underwent surgical treatment of IS via lumbar fusion from January 2016 through December 2021.

OUTCOME MEASURES

(1) Effective radiation dose and lifetime cancer risk associated with each exposure to ionizing radiation; (2) Difference in effective radiation dose (and lifetime cancer risk) among patients who received intraoperative CT compared to other intraoperative imaging techniques.

METHODS

Baseline demographics and differences in surgical techniques were characterized. Radiation exposure data were collected from the 2-year period centered on the operative date. Projected risk of cancer from this radiation was calculated utilizing each patient's effective radiation dose in combination with age and sex. Generalized linear modeling was used to adjust for covariates when determining the comparative risk of intraoperative CT as compared to alternative imaging modalities.

RESULTS

We included 151 patients in this cohort. The range in calculated cancer risk exclusively from IS management was 1.3-13 cases of cancer per 1,000 patients. During the intraoperative period, CT imaging was found to significantly increase radiation exposure as compared to alternate imaging modalities (adjusted risk difference (ARD) 12.33mSv; IQR 10.04, 14.63mSv; p<.001). For a standardized 40 to 49-year-old female, this projects to an additional 0.72 cases of cancer per 1,000. For the entire 2-year perioperative care episode, intraoperative CT as compared to other intraoperative imaging techniques was not found to increase total ionizing radiation exposure (ARD 9.49mSv; IQR -0.83, 19.81mSv; p=.072). The effect of intraoperative imaging choice was mitigated in part due to preoperative (ARD 13.1mSv, p<.001) and postoperative CTs (ARD 22.7mSv, p<.001).

CONCLUSIONS

Preference-sensitive imaging decisions in the treatment of IS impart substantial cancer risk. Important drivers of radiation exposure exist in each phase of care, including intraoperative CT and/or CT scans during the perioperative period. Knowledge of these data warrant re-evaluation of current imaging protocols and suggest a need for the development of radiation-sensitive approaches to perioperative imaging.

Usefulness of discography, discoblock and a new mechanical method for identifying a painful segment/disc

BACKGROUND

We previously described a procedure for eliciting deep spatial discrimination of individual segments in the healthy lumbar spine of normal subjects: the percutaneous mechanical provocation (PMP) test. Our goal was to devise a method for accurate identification of the spinal level of pathology in chronic low back pain (CLBP). In the present study, we validated the PMP test, using a subgroup of CLBP patients with isthmic spondylolisthesis (IS). Because there is clinical consensus that IS back pain originates in the slipped segment/disc, the level of pathology can be directly compared to the result of the PMP test. The test is agnostic with respect to the underlying pathological mechanism, and therefore might be useful in identifying the involved segment(s) irrespective of the painful structure.

METHODS

In 37 patients with confirmed IS (slippage 3-15mm), we compared sensitivity between the PMP test, the widely used provocative discography test and the discoblock test.

RESULTS

The PMP test reliably identified the slip level in patients with IS, with sensitivity of 92%. Accepting the slipped disc as the origin of pain in IS, the sensitivity of the provocative discography and discoblock tests were 49% and 35%, respectively: i.e., too low to be contributive in clinical practice.

CONCLUSIONS

The PMP test reliably identified the origin of localized pain in IS as the slip level, but should be used with care in CLBP patients in selecting discogenic pain patients for fusion surgery, since the specificity of the test is not known and it may be positive for any origin of localized pain.

Is quality of life after surgery for adolescent idiopathic scoliosis affected by the presence of a concomitant low-grade isthmic spondylolisthesis non-surgically treated? A retrospective cohort study

PURPOSE

The HRQoL after surgery for adolescent idiopathic scoliosis (AIS) is not affected by the presence of concomitant isthmic spondylolisthesis non-surgically treated. Improvement in QoL after surgery was similar for AIS patients with and without concomitant spondylolisthesis. The purpose is to compare preoperative and postoperative Health-Related Quality of Life (HRQoL) scores in operated AIS patients with and without concomitant isthmic spondylolisthesis.

METHODS

A retrospective study of a prospective cohort of 464 individuals undergoing AIS surgery between 2008 and 2018 was performed. All patients undergoing surgery for AIS with a minimum 2-year follow-up were included. We excluded patients with prior or concomitant surgery for spondylolisthesis. HRQoL scores were measured using the SRS-22 questionnaire. Comparisons were performed between AIS patients with versus without concomitant spondylolisthesis treated non-surgically.

RESULTS

AIS surgery was performed for 36 patients (15.2 ± 2.5 y.o) with concomitant isthmic spondylolisthesis, and 428 patients (15.5 ± 2.4 y.o) without concomitant spondylolisthesis. The two groups were similar in terms of age, sex, preoperative and postoperative Cobb angles. Preoperative and postoperative HRQoL scores were similar between the two groups. HRQoL improved significantly for all domains in both groups, except for pain in patients with spondylolisthesis. There was no need for surgical treatment of the spondylolisthesis and no slip progression during the follow-up duration after AIS surgery.

CONCLUSION

Patients undergoing surgical treatment of AIS with non-surgical management of a concomitant isthmic grade I spondylolisthesis can expect improvement in HRQoL scores, similar to that observed in patients without concomitant spondylolisthesis.

Comparing Patient-Reported Outcomes in Patients Undergoing Lumbar Fusion for Isthmic Spondylolisthesis with Predominant Back Pain versus Predominant Leg Pain Symptoms

OBJECTIVE

To compare patient-reported outcome measures (PROMs) and minimum clinically important difference (MCID) achievement following anterior or transforaminal lumbar interbody fusion for isthmic spondylolisthesis in patients presenting with predominant back pain versus predominant leg pain symptoms.

METHODS

A single-surgeon database was reviewed for anterior or transforaminal lumbar interbody fusion procedures for isthmic spondylolisthesis. Patient demographics, perioperative characteristics, postoperative complications, and PROMs were collected. Demographic/perioperative characteristics were compared among groups using χ² and Student t tests for categorical and continuous variables, respectively. Mean PROM scores were compared using an unpaired Student t test. Postoperative improvement from preoperative baseline within each cohort was assessed with paired-samples t test. MCID achievement rates were compared with χ² analysis.

RESULTS

In total, 143 patients were included with 65 patients in the predominant back pain and 78 patients in the predominant leg pain cohort. Preoperative visual analog scale (VAS) leg was noted to be significantly greater in predominant leg pain cohort (P < 0.001). Cohorts demonstrated significant mean postoperative differences for the following PROMs at the following postoperative time points: significant differences were noted between cohorts for rate of achievement of MCID for the following PROMs at the following time points: VAS back at 2 years and VAS leg at 6 weeks/12 weeks/6 months/overall (P < 0.036, all).

CONCLUSIONS

Compared with patients presenting for surgery with predominant leg pain symptoms, patients undergoing lumbar fusion at L4-L5 and L5-S1 for isthmic spondylolisthesis with predominant back pain symptoms may demonstrate improved long-term clinical outcomes for reported back pain, leg pain, and disability and reduced postoperative length of stay and narcotic consumption.

Management of lumbar spondylolysis in the adolescent athlete: a review of over 200 cases

BACKGROUND

Spondylolysis is a defect of the pars interarticularis of vertebrae, most commonly seen at L5 and L4. The etiology of spondylolysis and isthmic spondylolisthesis is generally considered to be a result of repetitive mechanical stress to the weak portion of the vertebrae. A higher incidence of spondylolysis is observed in young athletes. Symptomatic spondylolysis can be successfully treated conservatively, but there is currently a limited consensus on treatment modalities and a lack of large-scale clinical trials.

PURPOSE

The purpose of the present study was to investigate the optimal treatment algorithm for symptomatic spondylolysis in adolescent athletes and evaluate the functional outcomes of those undergoing the nonoperative treatment.

STUDY DESIGN

A retrospective review.

PATIENT SAMPLE

Two hundred one adolescent patients ranging from age 10 to 19 involved in athletics OUTCOME MEASURES: Injury characteristics (age, mechanism, time), sports played, bone stimulator use, bony healing at 3 months on computed tomography (CT) scans, return to sports, corticosteroid injection use.

METHODS

Two hundred one adolescent athlete patients (62 females and 139 males) diagnosed with spondylolysis between 2007 and 2019 were retrospectively reviewed. Diagnosis was based on plain radiography followed by magnetic resonance imaging. All patients were treated conservatively with cessation of sports activity, thoracolumbosacral orthosis, and external bone stimulator for three months after diagnosis. CT scans were obtained for the 3-month follow-up visits to assess bony healing. Subsequently the patients received 6 weeks of rehabilitation focused on core strengthening. Symptomatic patients after the treatment were referred for steroid injections and continued with the rehabilitation protocol.

RESULTS

The most common age of injury was 15 years old, following a strong normal distribution. The most commonly played sport was football, followed by baseball/softball. The primary mechanism of injury was weight training closely followed by a football injury. The first quarter of the calendar year had the highest incidence of injuries with the most injuries occurring in March and the least occurring in December. One hundred fifty-two athletes reported using bone stimulators as prescribed, and these patients showed a significantly higher rate of bony healing on follow-up CT scans than those who did not use bone stimulators. One hundred ninety-seven patients (98%) returned to sports or similar level of activities. Thirty-seven patients (18%) received facet or epidural steroid injections due to continued pain and one patient underwent a surgical procedure. Follow-up CT scans showed 49.8% bony healing.

CONCLUSIONS

Conservative treatment of spondylolysis in adolescent athletes with cessation of sports, thoracolumbosacral orthosis, and bone stimulator followed by rehabilitation was associated with excellent outcomes in terms of return to sports.

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

Background

This study aimed to analyze the efficacy of the simultaneous rectification of adjacent asymptomatic lumbar disc herniation (asLDH) of L5-S1 isthmic spondylolisthesis (IS).

Methods

One 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.

Results

The 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).

Conclusions

L4-S1 PLIF is recommended to correct asLDH in L5-S1 IS patients, with high-grade disc herniation and abnormal sagittal alignment.

Does minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) influence functional outcomes and spinopelvic parameters in isthmic spondylolisthesis?

PURPOSE

We assessed the efficacy of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in patients with low-grade isthmic spondylolisthesis.

METHODS

We included 24 symptomatic patients who underwent MIS-TLIF between December 2017 and December 2020. Patients were followed up clinically by the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) for back and VAS for leg pain, as well as radiological radiographs after 6 weeks, 6 months, and at final follow-up (at least 12 months). Measured parameters included C7 sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), Meyerding slip grades, lumbar lordosis (LL), L1-L4 angle, L4-S1 angle, and segmental lordosis (SL) of the affected segment. The mismatch between the PI and LL was also measured.

RESULTS

VAS for back, VAS for leg pain, and ODI significantly improved postoperatively (all p < 0.001). We observed significantly decreased mean values of PT and slip percentage and increased mean values of SS and LL (all p < 0.05). We observed a significant reduction in L1-L4 lordosis and a significant increase in L4-S1 lordosis. The final PT, SS, and LL (total and L1-L4) were significantly higher in group III patients (n = 15) than the values of group II patients (n = 9). None of the patients became unbalanced postoperative, and all patients had a normal matching between the PI and the LL postoperatively.

CONCLUSIONS

MIS-TLIF is a safe procedure for managing low-grade isthmic spondylolisthesis with significant improvement in clinical and radiological outcomes. It can correct and maintain a proper spinopelvic alignment.

Influence of Preoperative 12-Item Short Form Mental Composite Score on Clinical Outcomes in an Isthmic Spondylolisthesis Population Undergoing Minimally Invasive Transforaminal Lumbar Interbody Fusion

OBJECTIVE

To determine preoperative 12-Item Short Form Health Survey (SF-12) Mental Component Summary (MCS) influence on minimally important clinical difference (MCID) and patient-reported outcome measures in patients with isthmic spondylolisthesis receiving minimally invasive transforaminal lumbar interbody fusion.

METHODS

Patients with isthmic spondylolisthesis undergoing primary, single-level minimally invasive transforaminal lumbar interbody fusion at L5-S1 were retrospectively identified and divided into preoperative SF-12 MCS <50 and SF-12 MCS ≥50 groups. Visual analog scale (VAS) back/leg, Oswestry Disability Index (ODI), SF-12 Physical Composite Score (PCS), and Patient-Reported Outcome Measurement Information System physical function (PROMIS-PF) were assessed. Improvements from preoperative score were analyzed via paired samples t test. Patient-reported outcome measures and MCID attainment between groups were evaluated using linear regression and χ², respectively.

RESULTS

SF-12 MCS <50 and SF-12 MCS ≥50 groups included 35 and 26 patients, respectively. SF-12 MCS < 50 group had inferior scores for all VAS back time points except 6 weeks, all VAS leg time points except 6 weeks/1 year, all ODI time points, SF-12 PCS at 6 months/2 years, and PROMIS-PF at preoperative/6 months (all P ≤ 0.049). SF-12 MCS <50 group improved for VAS back/leg to 1 year, ODI and SF-12 PCS from 12 weeks to 1 year, and PROMIS-PF at 1 year only (all P ≤ 0.047). SF-12 MCS ≥50 group improved for VAS back from 12 weeks to 1 year, SF-12 PCS 6 months to 2 years, and VAS leg, ODI, and PROMIS-PF 12 weeks to 2 years (all P ≤ 0.018). MCID attainment differed for ODI at 6 weeks and PROMIS-PF at 12 weeks only (both P ≤ 0.035).

CONCLUSIONS

Patients with SF-12 MCS <50 demonstrated fewer long-term improvements from preoperative to 2 years and inferior patient-reported outcome measures at most time points for pain and disability following minimally invasive transforaminal lumbar interbody fusion. MCID attainment largely did not differ by preoperative mental functioning.

Circumferential fusion with open versus percutaneous posterior fusion for lumbar isthmic spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate the clinical and radiographic differences between patients who underwent anterior lumber interbody fusion (ALIF) with either open or percutaneous posterior fusion for lumbar isthmic spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Circumferential fusion for isthmic spondylolisthesis is commonly performed with superior clinical outcomes, fusion rates, and restoration of sagittal balance when compared to posterior fusion alone. The outcomes comparing traditional open versus percutaneous posterior fusion in this setting have not been fully evaluated.

METHODS

A retrospective review of patients who underwent ALIF with either traditional open or percutaneous posterior fusion for isthmic spondylolisthesis between 2014 and 2019 was conducted. Patient demographics, surgical characteristics, and radiographic and clinical outcomes were compared between groups.

RESULTS

A total of 79 patients were included in the final analysis, with 49 in the Open group and 30 in the Percutaneous group. No differences were found with regard to demographic factors between groups including sex, body mass index (BMI), diabetic status, and smoking status. The percutaneous group had less estimated blood loss (EBL, 69.2 mL) and shorter length of stay (3.06 days) compared to the open group (446 mL, p = 0.017; 3.98 days, p = 0.003). Both groups demonstrated significant improvement in all clinical outcome measures after surgery (PCS-12, MCS-12, ODI, VAS Back, and VAS Leg scores). The percutaneous group achieved greater ∆VAS Back (Open = 3.55, Perc = 5.17; p = 0.045) and also had a significantly greater improvements in recovery ratio for VAS Back (Open: 0.43, Perc: 0.73; p = 0.037) and ODI (Open: 0.40, Perc = 0.67; p = 0.031). Regression analysis demonstrated percutaneous surgery to be significant predictor of superior improvement in VAS Back scores (β = 1.957, p = 0.027).

CONCLUSION

ALIF with percutaneous posterior fusion affords greater improvement in back pain and disability when compared to ALIF with open posterior fusion for isthmic spondylolisthesis.

LEVEL OF EVIDENCE

III.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

The necessity and risk factors of subsequent fusion after decompression alone for lumbar spinal stenosis with lumbar spondylolisthesis: 5 years follow-up in two different large populations

BACKGROUND/CONTEXT

Although decompression without fusion is a reasonable surgical treatment option for some patients with lumbar spinal stenosis (LSS) secondary to spondylolisthesis, some of these patients will require secondary surgery for subsequent fusion. Long-term outcome and need for subsequent fusion in patients treated with decompression alone in the setting of lumbar spondylolisthesis remains controversial.

PURPOSE

The aim of this study was to examine the rate, timing, and risk factors of subsequent fusion for patients after decompression alone for LSS with spondylolisthesis.

STUDY DESIGN/SETTING

A retrospective cohort study.

PATIENT SAMPLE

Patients who had LSS with spondylolisthesis and underwent decompression alone at 1 or 2 levels as a primary lumbar surgery with more than 5 year follow-up.

OUTCOME MEASURES

The rate, timing, and risk factors for subsequent fusion.

METHODS

Subjects were extracted from both public and private insurance resources in a nationwide insurer database. Risk factors for subsequent fusion were evaluated by multivariate cox proportion-hazard regression controlling for age, gender, comorbidities and the presence or absence of claudication.

RESULTS

Five thousand eight hundred and seventy-five patients in the public insurance population (PI population) and 1,456 patients in the private insurance population (PrI population) were included in this study. The rates of patients who needed subsequent fusion were 1.9% at 1 year, 3.5% at 2 years, and 6.7% at 5 years in the PI population, whereas they were 4.3% at 1 year, 8.9% at 2 years, 14.6% at 5 years in the PrI population. The time to subsequent fusion was 730 (365-1234) days in the PI population and 588 (300-998) days in the PrI population. Age less than 70 years, presence of neurogenic claudication and rheumatoid arthritis (RA)/collagen vascular diseases (CVD) were independent risk factors for subsequent fusion in both populations.

CONCLUSIONS

Decompression surgery alone can demonstrate good outcomes in some patients with LSS with spondylolisthesis. It is important for surgeons to recognize, however, that patient age less than 70 years, symptomatic neurogenic claudication, and presence of RA and/or CVD are significant independent factors associated with greater likelihood of needing secondary fusion surgery.

Straighter low lumbar curvature in isthmic spondylolisthesis at L4

BACKGROUND

This study was conducted to compare differences in imaging features and clinical symptoms between patients with single-level isthmic spondylolisthesis (IS) at L4 and at L5 and to investigate the correlation between imaging and clinical parameters.

METHODS

This cross-sectional study evaluated patients with single-level IS who were enrolled between June 2011 and June 2018. A total of 139 patients, 44 in the L4 IS group and 95 in the L5 IS group, met the study criteria and were included. Imaging and clinical parameters obtained from the two groups were compared and analyzed.

RESULTS

Patients in the L4 IS group had smaller lower lumbar lordosis (LLL) (27.1 ± 8.2 vs. 30.9 ± 9.3, P = 0.021) and were of older age (58.5 ± 8.7 vs. 52.8 ± 10.1, P < 0.01) than those in the L5 IS group. As per the Roussouly classification system, most patients with L4 IS were classified as Type 2 (43.2%), whereas most patients with L5 IS fell under Type 3 (44.2%). In the L5 IS group, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), and L5 incidence (L5I) were positively associated with slippage rate (SR), but the lumbosacral angle (LSA) was negatively associated with SR (P < 0.01). In the L4 IS group, only L5I showed a positive association with SR (P < 0.01). More significant associations were found among sagittal lumbo-pelvic parameters in the L5 IS group, but none were found between SR and Oswestry Disability Index (ODI) in either group.

CONCLUSIONS

When compared with patients with L5 IS, patients with L4 IS were of older age and had straighter low lumbar curvature when they were obviously symptomatic. PI was an important parameter for patients with L5 IS while for those with L4 IS, L5I deserved more attention for its significantly positive correlation with the degree of slippage.

Ipsilateral Pedicle Stress Fracture After Endoscopic Foraminal Decompression for Patient with Isthmic Spondylolisthesis

BACKGROUND

Minimally invasive endoscopic spine surgery is useful for the treatment of various spinal conditions. Although surgery-related complications such as dural injury, exiting nerve root injury, incomplete decompression, and hematoma have been reported, there are few reports of late complications after endoscopic surgery.

CASE DESCRIPTION

A 51-year-old man complained of radiating pain to the right leg. The patient underwent endoscopic foraminal decompression under the diagnosis of foraminal stenosis with isthmic type spondylolisthesis (L5-S1). The lower extremity radiating pain was improved after surgery. Six weeks after surgery, the patient's symptoms recurred. The patient experienced a sudden onset of severe low back pain, which was aggravated by any motion of the lumbar spine. Computed tomography scan and magnetic resonance imaging revealed a fracture line with a sclerotic margin at the base of the right pedicle at the L5 level. Because the symptoms significantly interfered with his normal activities of daily living, the patient was treated with a total laminectomy, followed by posterior instrumented fusion. As the indication for endoscopic spinal surgery is widening, endoscopic decompression surgery is being performed for patients with low-grade lumbar spondylolisthesis, regardless of the presence of advanced spinal instability. However, endoscopic decompression surgery may cause damage to the posterior facet joint, which may have worsened the instability and lead to late complications such as progression of spondylolisthesis and pedicle stress fracture.

CONCLUSIONS

The surgeon should carefully review risk factors such as isthmic type spondylolisthesis before planning spine surgery and minimize facet joint damage during endoscopic decompression.

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

Background

Recently, 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.

Methods

This 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.

Results

Based 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.

Conclusion

In 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.

High-Grade Lumbar Spondylolisthesis

Most high-grade spondylolistheses are resultant from isthmic spondylolisthesis, as complete discontinuity of the pars is typically necessary to allow for this degree of anterior vertebral translation, although can occur less commonly in other scenarios. Higher-grade slips can affect the global sagittal balance of the patient and often result in altered gait patterns and compensatory posturing. Management usually entails surgical decompression and fusion with instrumentation. The addition of anterior column support carries many advantages, including greater surface area for fusion, dynamic compression load sharing at the lumbosacral junction, and a powerful adjunct for deformity correction.

Sagittal reconstruction of lumbosacral contiguous double-level spondylolytic spondylolisthesis: a comparison of double-level and single-level transforaminal lumbar interbody fusion

Background

Contiguous double-level lumbar spondylolytic spondylolisthesis is an extremely rare condition. There is a paucity of data of lumbosacral deformity and sagittal spino-pelvic malalignment among these patients. Moreover, the effect of transforaminal lumbar interbody fusion (TLIF) on sagittal realignment still remains largely unknown. The aim of the study is to investigate the reconstruction of sagittal alignment and the improvement of clinical outcomes after posterior instrumented double-level or single-level TLIF.

Methods

From January 2010 to September 2018, the records of patients with contiguous L4/5 and L5/S1 double-level spondylolytic spondylolisthesis were retrospectively reviewed. Patients who had undergone double-level or single-level TLIF and a minimum of 2 years’ follow-up were included. The slippage parameters and spino-pelvic parameters were measured preoperatively, postoperatively, and at the latest follow-up.

Results

A total of 58 patients (21 males and 37 females, mean age of 57.1 ± 6.9 years) were enrolled. Thirty-eight patients were treated with double-level TLIF and the remaining 20 with single-level TLIF (L4/5 in 14; L5/S1 in 6). After surgery, the spondylolisthesis was significantly reduced at both L4/5 and L5/S1 level (all P < 0.001). There was a significant reduction in pelvic tilt (P < 0.001) and a significant increase in sacral slope (P < 0.001). Significant increase in L4–S1 height (P < 0.001) and L4–S1 lordosis (P = 0.012) and decrease in L5 slope (P = 0.004) and L5 incidence (P = 0.001) were also observed. Compared to single-level TLIF, double-level TLIF increased L4–S1 height (P < 0.001) and L4–S1 lordosis (P < 0.001) and reduced L4-SVA (P = 0.007) and L5 incidence (P = 0.013) more obviously, and the sagittal balance was better corrected in double-level TLIF group (P = 0.006). Double-level TLIF group showed larger increase in VAS scores for low back pain. The incidence of implant-related complications was lower in the double-level group.

Conclusion

Posterior short-segment instrumented TLIF can bring favorable radiographic and clinical outcomes in patients with lumbosacral contiguous double-level spondylolytic spondylolisthesis. Double-level TLIF is more efficient to improve L4–S1 height, regional lumbar lordosis, and global sagittal balance.

Long-term outcome after spinal fusion for isthmic spondylolisthesis in adults

BACKGROUND CONTEXT

Data on the long-term outcome after fusion for isthmic spondylolisthesis are scarce.

PURPOSE

To study patient-reported outcomes and adjacent segment degeneration (ASD) after fusion for isthmic spondylolisthesis and to compare patient-reported outcomes with a control group.

STUDY DESIGN/SETTING

A prospective study including a cross-sectional control group.

PATIENT SAMPLE

Patients with isthmic spondylolisthesis underwent posterior lumbar interbody fusion (PLIF) (n=86) or posterolateral fusion (PLF) (n=77). Patient-reported outcome data were available for 73 patients in the PLIF group and 71 in the PLF group at a mean of 11 (range 5-16) years after baseline. Seventy-seven patients in the PLIF group and 54 in the PLF group had radiographs at a mean of 14 (range 9-19) years after baseline. One hundred thirty-six randomly selected persons from the population served as controls for the patient-reported outcomes.

OUTCOME MEASURES

Patient-reported outcomes include the following: global outcome, Oswestry Disability Index, Disability Rating Index, and Short Form 36. The ASD was determined from radiographs using the University of California Los Angeles (UCLA) grading scale.

METHODS

The chi-square test or analysis of covariance (ANCOVA) was used for group comparisons. The ANCOVA was adjusted for follow-up time, smoking, Meyerding slippage grade, teetotaler (yes/no) and, if available, the baseline level of the dependent variable.

RESULTS

There were no significant patient-reported outcome differences between the PLIF group and the PLF group. The prevalence of ASD was 42% (32/77) in the PLIF group and 26% (14/54) in the PLF group (p=.98). The patient-reported outcome data indicated lower physical function and more pain in individuals with surgically treated isthmic spondylolisthesis compared to the controls.

CONCLUSIONS

PLIF and PLF groups had similar long-term patient-reported and radiological outcomes. Individuals with isthmic spondylolisthesis have lower physical function and more pain several years after surgery when compared to the general population.

Does minimally invasive fusion technique influence surgical outcomes in isthmic spondylolisthesis?

OBJECTIVE

To compare the clinical and radiographic results between open transforaminal interbody fusion (TLIF-O) and minimally invasive TLIF (TLIF-M) for single-level low grade isthmic spondylolisthesis (IS).

METHODS

This study enrolled 45 patients who underwent single-level TLIF with low grade IS. The patients were divided into two groups according to operative method: TLIF-M (20 patients) and TLIF-O (25 patients). TLIF-O group was matched with TLIF-M.

RESULTS

At one-year postoperatively, there were no significant differences in any radiologic parameters between the two groups. Perioperative results such as blood loss, operation time, and hospital stay were superior in TLIF-M than in TLIF-O. Fusion was achieved in 17 of 20 patients (85.0%) in TLIF-M and 23 of 25 (92.0%) patients in TLIF-O. Back Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores of TLIF-O were significantly lower than TLIF-M at one (back VAS, ODI) and six months (ODI) postoperatively.

CONCLUSIONS

TLIF-M and TLIF-O produced similar clinical and radiological outcomes, including reduction of spondylolisthesis and disc space height restoration at one-year follow-up for single-level low grade IS. However, considering perioperative outcomes, back pain, and quality of life, TLIF-M might be a better option for single-level low grade IS compared to TLIF-O.

Circumferential minimally invasive approach for low-grade isthmic spondylolisthesis: A clinical and radiological study of 43 patients

INTRODUCTION

Circumferential fusion for lumbar low-grade isthmic spondylolisthesis (LGIS) provides the best spinal stability and highest fusion rates. The aim of this study is to investigate results of minimal invasive management of LGIS and correlations between Intervertebral Foramen Surface (IFS) and other parameters.

METHODS

We retrospectively reviewed cases of 43 patients who underwent a minimally invasive circumferential fusion (Anterior lumbar interbody fusion followed by percutaneous posterior pedicle screw fixation) for LGIS between January 2010 and December 2014 in our institution. Inclusion criteria were one-level (L4-L5 or L5-S1) LGIS with low back and/or radicular pain. Pre- and postoperative radiographic evaluations were performed at 6, 12 and 24months. Measurements (Percentage of anterior displacement, degree of slip angle, height of the intervertebral space and the IFS) were obtained using Surgimap^®.

RESULTS

Nineteen patients (44.2%) were males. Mean age was 43 years old (19-72years). The mean follow-up of the series was 18.3months (3-72months). Mean preoperative Visual Analogy Scale (VAS) for low back pain decreased from 70mm to 20mm and from 80mm to 10mm as to radicular pain. Anterior displacement was reduced from 18% to 7% (p<0.01), degree of slippage were increased from 9.8° to 15.2° (p<0.01), intervertebral height was restored from 4.4mm to 8.5mm (p<0.01) and increase of the IFS was calculated 48.8%.

CONCLUSION

One stage circumferential fixation for adults' LGIS without decompression, allows restoration of intervertebral height permitting good reduction of the slippage, an increasing of the IFS and liberation of nerve roots.

A systematic review of clinical outcomes in surgical treatment of adult isthmic spondylolisthesis

BACKGROUND CONTEXT

A variety of surgical methods are available for the treatment of adult isthmic spondylolisthesis, but there is no consensus regarding their relative effects on clinical outcomes.

PURPOSE

To compare the effects of different surgical techniques on clinical outcomes in adult isthmic spondylolisthesis.

DESIGN

A systematic review was carried out.

PATIENT SAMPLE

A total of 1,538 patients from six randomized clinical trials (RCTs) and nine observational studies comparing different surgical treatments in adult isthmic spondylolisthesis.

OUTCOME MEASURES

Primary outcome measures of interest included differences in pre- versus postsurgical assessments of pain, functional disability, and overall health as assessed by validated pain rating scales and questionnaires. Secondary outcome measures of interest included intraoperative blood loss, length of hospital stay, surgery duration, reoperation rates, and complication rates.

METHODS

A search of the literature was performed in September 2017 for relevant comparative studies published in the prior 10-year period in the following databases: PubMed, Embase, Web of Science, and ClinicalTrials.gov. Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed and studies were included or excluded based on strict predetermined criteria. Quality appraisal was conducted using the Newcastle-Ottawa scale (NOS) for observational studies and the Cochrane Collaboration risk of bias assessment tool for RCTs. The authors received no funding support to conduct this review.

RESULTS

A total of 15 studies (six RCTs and nine observational studies) were included for full-text review, a majority of which only included cases of low-grade isthmic spondylolisthesis. One study examined the effects of adding pedicle screw fixation (PS) to posterolateral fusion (PLF) and two studies examined the effects of adding reduction to interbody fusion (IF)+PS on clinical outcomes. Five studies compared PLF, four with PS and one without PS, with IF+PS. Additionally, three studies compared circumferential fusion (IF+PS+PLF) with IF+PS and one study compared circumferential fusion with PLF+PS. Three studies compared clinical outcomes among different IF+PS techniques (anterior lumbar IF [ALIF]+PS vs. posterior lumbar IF [PLIF]+PS vs. transforaminal lumbar IF [TLIF]+PS) without PLF. As per the Cochrane Collaboration risk of bias assessment tool, four RCTs had an overall low risk of bias, one RCT had an unclear risk of bias, and one RCT had a high risk of bias. As per the NOS, three observational studies were of overall good quality, four observational studies were of fair quality, and two observational studies were of poor quality.

CONCLUSIONS

Available studies provide strong evidence that the addition of reduction to fusion does not result in better clinical outcomes of pain and function in low-grade isthmic spondylolisthesis. Evidence also suggests that there is no significant difference between interbody fusion (IF+PS) and posterior fusion (PLF±PS) in outcomes of pain, function, and complication rates at follow-up points up to approximately 3 years in cases of low-grade slips. However, studies with longer follow-up points suggest that interbody fusion (IF+PS) may perform better in these same measures at later follow-up points. Available evidence also suggests no difference between circumferential fusion (IF+PS+PLF) and interbody fusion (IF+PS) in outcomes of pain and function in low-grade slips, but circumferential fusion has been associated with greater intraoperative blood loss, longer surgery duration, and longer hospital stays. In terms of clinical outcomes, insufficient evidence is available to assess the utility of adding PS to PLF, the relative efficacy of different interbody fusion (IF+PS) techniques (ALIF+PS vs. TLIF+PS vs. PLIF+PS), and the relative efficacy of circumferential fusion and posterior fusion (PLF+PS).

Minimally invasive surgery procedure in isthmic spondylolisthesis

PURPOSE

The aim of the study was to evaluate the efficacy and safety of the direct lateral approach to the lumbar spine in the treatment of painful isthmic spondylolisthesis in adults.

METHODS

Twenty-one patients affected by isthmic spondylolisthesis and treated with extreme lateral interbody fusion and posterior percutaneous pedicle screw fixation were enrolled. All included patients were clinically evaluated with Oswestry Disability Index, SF36 and Visual Scale Anatomy (VAS) for back pain at 1, 3 months and at 1 year.

RESULTS

The mean correction of vertebral slippage measured on lateral lumbar X-ray was 56.3% (p = 0.002). The average preoperative VAS score was 7.1, at 1 year decreasing to 2.2 (p = 0.001). The patients had an average preoperative "Oswestry Disability Index" of 36.8 and 24.1% after 1 year (p = 0.02). The preoperative Short-Form 36 Physical Health was equal to 33.8, 72.1% after 1 month, to 76.3% after 3 months and to 83.2% (p = 0.001) after 1 year of follow-up. There were no signs of implant loosening at 1-year CT scan examination in any of the patients.

CONCLUSION

The study showed that the extreme lateral approach to the lumbar spine in case of isthmic spondylolisthesis is a reliable and safe option to the most common open procedures. In the authors' opinion, XLIF procedures allow a good correction of the listhesis associated with good clinical and radiographic results. These slides can be retrieved under Electronic supplementary material.

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 CONTEXT

Transforaminal 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.

PURPOSE

To define the clinical, radiographic, and financial differences between TLIF and ALIFPS for L5-S1 IS.

DESIGN/SETTING

A retrospective cohort study conducted at a single tertiary care center.

PATIENT SAMPLE

Sixty-six patients who underwent either TLIF or ALIPFS for L5-S1 IS at a single tertiary care center between 2009 and 2014.

OUTCOME MEASURES

Quality 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.

METHODS

Quality 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).

RESULTS

A 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.

CONCLUSIONS

Our 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

OBJECTIVE

To investigate facet tropism and its role in development of lumbar isthmic spondylolisthesis (IS) in young men.

METHODS

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 (46 patients 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.

RESULTS

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).

CONCLUSIONS

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.

Rheumatoid arthritis-associated spinal neuroarthropathy with double-level isthmic spondylolisthesis

INTRODUCTION

To the best of our knowledge, there has been no report regarding rheumatoid arthritis associated with spinal neuroarthropathy and combined double-level isthmic spondylolisthesis. Here, we report a rare case of spinal neuroarthropathy with double-level isthmic spondylolisthesis in a rheumatoid arthritis (RA) patient. A 56-year-old female patient under medical treatment for RA during the last 13 years presented aggravating radiating pain to her right lower extremity and a limping gait developed 4 months ago. The disease activity of RA had remained low for a long time. Serial radiographs during last 8-year follow-up showed progressive dislocation at L4-L5 and L5-S1 with double-level isthmic spondylolisthesis and severe destructive status at the last follow-up. The patient underwent decompression and circumferential fusion with sacropelvic fixation and acceptable reduction was obtained.

CONCLUSION

A RA patient with double-level isthmic spondylolisthesis showed a progressive destructive lesion. In addition to clinical presentations, the imaging findings were very similar to ones of spinal neuroarthropathy. The authors conclude that this Grand Round case probably had SNA secondary to RA and that this, combined with two-level isthmic spondylolisthesis, resulted in her rapidly progressing destructive lumbar lesion.

Outcomes of autograft alone versus PEEK+ autograft interbody fusion in the treatment of adult lumbar isthmic spondylolisthesis

OBJECTIVES

Bone resulting from a complete resection of the posterior arch can be cut into an autograft bone that contains the facet joint structure and morselised bone for interbody fusion. However, whether a strut autograft that contains this trimmed facet joint can produce the same clinical and radiographic outcomes as a cage for interbody fusion remains unclear. The aim of this study was to compare the outcomes of a local facet joint autograft alone to those of polyetheretherketone (PEEK)+autograft for posterior lumbar interbody fusion (PLIF) in the treatment of adult isthmic spondylolisthesis.

PATIENTS AND METHODS

A retrospective analysis was performed on 84 patients with single lumbar isthmic spondylolisthesis who were treated with a local facet joint autograft alone (group A; n=44) or PEEK+autograft (group B; n=40) in PLIF with a minimum follow-up period of 24 months. Pain and disability were assessed using the visual analogue scale, Oswestry disability index and Kirkaldy-Willis criteria. In the radiological evaluation, disc height, slippage reduction, and fusion status were examined. Postoperative complications were also monitored.

RESULTS

At the last follow-up examination, 84.1% (37/44) of the patients in group A and 82.5% (33/40) of the patients in group B had a good outcome, and there were no significant differences between the two groups. Boh Methods led to significant improvements in disc height, and while PEEK+autograft produced a smaller loss in disc height, the difference was insignificant. The improvements in slippage and the fusion and complication rates between the two groups were similar.

CONCLUSION

There were no significant differences in the clinical outcomes or radiographic improvements of both fusion methods in the treatment of adult isthmic spondylolisthesis. An autograft excised from a complete posterior arch containing a facet joint for interbody fusion is effective and affordable for treating isthmic spondylolisthesis.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of adult isthmic spondylolisthesis

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Adult Isthmic Spondylolisthesis features evidence-based recommendations for diagnosing and treating adult patients with isthmic spondylolisthesis. The guideline is intended to reflect contemporary treatment concepts for symptomatic isthmic spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of June 2013. NASS' guideline on this topic is the only guideline on adult isthmic spondylolisthesis accepted in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse.

PURPOSE

The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with isthmic spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

This is a guideline summary review.

METHODS

This guideline is the product of the Adult Isthmic Spondylolisthesis Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questionsto address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Adult Isthmic Spondylolisthesis guideline was accepted into the National Guideline Clearinghouse and will be updated approximately every 5 years.

RESULTS

Thirty-one clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature.

CONCLUSIONS

The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with isthmic spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule.

Correlation between correction of pelvic balance and clinical outcomes in mid- and low-grade adult isthmic spondylolisthesis

BACKGROUND

Pelvic balance is a version of the pelvis defined by pelvic orientation parameters of PT and SS. Two distinct versions of pelvis are defined: (1) balanced characterized by a relatively low PT and high SS, and (2) unbalanced with relatively high PT and low SS meaning excessive retroversion of the pelvis. It was proved for patients with a high-grade spondylolisthesis that rebalancing of the pelvis can positively affect clinical outcomes. Little is known about the impact of such rebalancing in low-grade isthmic spondylolisthesis.

PURPOSE

To determine whether clinical outcomes correlated with rebalancing of the pelvis after surgical correction of mid- and low-grade adult isthmic spondylolisthesis.

METHODS

One hundred and three adult patients with a mid- and low-grade isthmic slip were the participants. Clinical outcomes were assessed at least 2 years after the surgery with the use of the Oswestry Disability Index (ODI) and a back pain visual analogue scale. Statistical analysis was used to identify differences in clinical outcomes between patients (1) with a balanced and unbalanced pelvis postoperatively, (2) who regained and did not regain pelvic balance postoperatively, (3) who maintained and lost pelvic balance postoperatively, and (4) with reduced and increased postoperative PT.

RESULTS

There were no significant differences in clinical outcomes between patients with a balanced and unbalanced pelvis postoperatively regardless of whether they lost, maintained, or regained pelvic balance after the surgery (Student's t test for independent variables or the non-parametric Mann-Whitney U, p value = 0.05). No correlation (Spearman's rank correlation) was found between postoperative reduction of PT and postoperative: (1) level of back pain (r = -0.10, p = 0.3063), (2) degree of reduction in back pain (r = 0.03, p = 0.7927), (3) ODI scores (r = -0.18, p = 0.0696), and (4) degree of reduction in ODI scores (r = 0.13, p = 0.1893).

CONCLUSIONS

Radiological improvement of pelvic balance after surgical correction of mid- and low-grade isthmic spondylolisthesis did not correlate with clinical outcomes.

Multiple Osseous Loose Bodies Associated with Lumbar Isthmic Spondylolisthesis

BACKGROUND

Multiple osseous loose bodies in the lumbar spine have never been reported. We describe a rare surgical case of multiple osseous loose bodies associated with lumbar isthmic spondylolisthesis.

CASE DESCRIPTION

A 74-year-old man who experienced left foot numbness and bilateral gluteal pain was diagnosed with lumbar spondylolisthesis 7 years previously and managed conservatively. He reported recurrence of the left foot numbness 6 months previously, at which time aggressive (rather than conservative) therapy became a consideration. Radiographs of the lumbar spine revealed L5 isthmic spondylolisthesis with dynamic instability at L5/S1. Magnetic resonance imaging of the lumbar spine revealed multiple mass lesions dorsally located in the lumbar canal. Computed tomography myelography demonstrated multiple osseous materials near the isthmic portion at the L5 level where compression of the dural sac by the lesions induced lumbar canal stenosis. The patient underwent posterior decompression surgery that enabled total removal of the osseous lesions. Intraoperative findings revealed osseous lesions located in the fibrocartilage material and no connection of the lytic portion at the L5 level or ligamentum flavum. Postoperative course of the patient was uneventful as his neurological symptoms improved.

CONCLUSIONS

We described the first instance of multiple loose bodies in the spinal canal with lumbar canal stenosis. It is presumed that long standing minor trauma due to dynamic instability with a trend of hyperossification induced secondary synovial osteochondromatosis forming multiple loose bodies.

Replacement of Vertebral Lamina (Laminoplasty) in Surgery for Lumbar Isthmic Spondylolisthesis: 5-Year Follow-Up Results

Study Design

A review of clinical and radiological outcomes of lumbar laminoplasty (LL) for the treatment of isthmic spondylolisthesis (ISL).

Purpose

The single session performance of posterior lumbar interbody fusion with allograft in the anterior column and providing the realignment of the vertebrae was presented as a preliminary report earlier.

Overview of Literature

Long-term surgical outcome of cervical laminoplasty in patients has been reported. But, outcome of LL in patients is unclear.

Methods

The long-term (5 years) year follow-up results of the LL technique are reported in this retrospective study. All patients underwent preoperative and postoperative direct X-ray, computed tomography, and magnetic resonance imaging. The patients that did not respond to conservative treatment were operated. Twenty-one (52.5%) female and 19 (47.5%) male patients were included.

Results

Mean age was 43,5 years (ranges, 22–57 years). The most common symptoms were low back pain (89%), pelvic and leg pain (69%) and reduction in walking distance (65%). A total of 180 pedicle screws were inserted in 40 patients; posterior lumbar interbody fusion and laminoplasty with reduction was performed in 20 patients for L4–L5, 12 patients for L5–S1, 4 patients for L3–L4–L5 and 4 patients for L4–L5-S1. Ten (25%) patients with ILL had accompanying spinal stenosis. The difference between preoperative and postoperative sagittal plane rotation and dislocation degrees and disc space heights were statistically significant in all patients (p<0.05). Solid grade 4 fusion was observed in 38 patients; in only 2 patients grade 2 pseudoarthrosis developed (5%), but these patients were asymptomatic. Visual analog scale, Prolo economical and functional scale was examined with an average follow-up 5.5 years.

Conclusions

LL technique has the advantages of shorter duration of operation, lack of graft donor site complications, protection of posterior column osseoligamentous structures and achievement of high fusion rates in one session.

Pedicle length and degree of slip in lumbosacral isthmic spondylolisthesis

OBJECTIVE

The present retrospective study was performed to assess the anatomical features of the pedicle in isthmic spondylolisthesis and to correlate this with degree of slip.

METHODS

Twenty-six patients with isthmic spondylolytic spondylolisthesis were studied. Relevant patient variables, length, width, height of the L5 pedicle, and the product of height and angle between pedicle and vertebral midline were measured. The length of the posterior compartment of the pedicle was calculated as the product of the pedicle length and angle.

RESULTS

With measurements comparable to those reported in previous publications, the L5 pedicle was found to be longer, and the height and width of the body shorter, than published values for patients without spondylolysis. The difference between the length of the posterior compartment of the pedicle and height of body is significantly proportional to the degree of slip and may reflect an adaptive response for stabilizing the vertebral body with posterior elements.

CONCLUSIONS

The pedicle anatomy was found to be altered in patients with L5 S1 spondylolytic spondylolisthesis. These anatomical changes have implications for surgeons performing fusion operations in terms of length of screw, landmarks used and entry approach.

Relationship between the spino-pelvic parameters and the slip grade in isthmic spondylolisthesis

PURPOSE OF THE STUDY

Analysis of changes in the spino-pelvic alignment, depending on the slip grade in patients with low and high-grade isthmic slip.

MATERIALS AND METHODS

A group of 60 patients who had lumbar spine radiograms adequate to measure the spino-pelvic parameters selected from a series of 195 cases of isthmic spondylolisthesis. We analyzed the following spino-pelvic parameters: pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbosacral angle by Dubousset (LSA) and lumbar lordosis (LL). The ANOVA statistical test was used to examine whether there is a significant correlation between (1) the slip grade and the value of PI, PT, and LL, and the Pearson correlation was used to examine a correlation between (2) the size of PI and the value of other spino-pelvic parameters, (3) the value of LL and SS, (4) value of the LSA and LL, PI and PT.

RESULTS

The greater the slip grade, the greater the value of PI, PT, and LL and lower LSA. Positive correlations have been found between PI and SS, PT and LL. There was also a positive correlation between LL and SS. Negative correlations were noted between LSA and LL, PI and PT.

CONCLUSION

The spino-pelvic alignment changes with the grade of isthmic spondylolisthesis, and the individual spino-pelvic parameters correlate together to form a causal chain in the development of isthmic spondylolisthesis.

Sacrum fracture following L5-S1 stand-alone interbody fusion for isthmic spondylolisthesis

We report a 72-year-old man with a rare sacral fracture following stand-alone L5-S1 anterior lumbar interbody fusion for isthmic spondylolisthesis. The man underwent a minimally invasive management strategy using posterior percutaneous pedicle fixation and partial reduction of the deformity. We also discuss the current literature on fusion procedures for isthmic spondylolisthesis.

Minimally Invasive Transforaminal Lumbar Interbody Fusion for Spondylolisthesis: Comparison Between Isthmic and Degenerative Spondylolisthesis

INTRODUCTION

Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is a common surgical option for degenerative spondylolisthesis (DS). However, its effectiveness for isthmic spondylolisthesis (IS) is still controversial. No current studies have directly compared perioperative and postoperative results including various radiological parameters between IS and DS after MIS TLIF.

PURPOSE

The purpose of this study is to compare the clinical and radiological results between isthmic and degenerative spondylolisthesis after MIS TLIF.

METHODS

This is a retrospective study of 41 patients who underwent MIS TLIF for single-segment, grade 1 or 2 IS (n = 18) and DS (n = 23). The same surgical techniques and procedure were applied to both groups. Perioperative outcomes (operation time, blood loss, hospital stay, complications); clinical outcomes (visual analog scale [VAS], Oswestry Disability Index [ODI]); radiological parameters (disk height, degree of spondylolisthesis, slip angle, lumbar lordosis, segmental lordosis, sacropelvic parameters: pelvic incidence, sacral slope, pelvic tile); and fusion rates using computed tomography scanning were compared between groups at 1 year postoperatively.

RESULTS

There were no significantly different perioperative results between groups. Mean VAS and ODI scores improved significantly postoperatively in both groups but were not significantly different between groups at each follow-up point. Radiological parameters were not significantly different between groups except disk height and degree of spondylolisthesis. The disk heights were increased postoperatively (IS: 6.79-9.22 mm; DS: 8.18-8.97 mm) in both groups, and there were significant differences preoperatively. In addition, disk height restoration was greater for IS than DS (2.43 mm vs. 0.79 mm, P = 0.01). However, postoperative disk heights were not significantly different between groups. The degree of spondylolisthesis was significantly different between groups both preoperatively (16.77% vs. 11.33%, P < 0.01) and postoperatively (9.79% vs. 3.78%, P < 0.01). However, slip reduction was no different between groups (6.97 vs. 7.56%, P = 0.74). Fusion rates were not significantly different between groups.

CONCLUSIONS

MIS TLIF resulted in similar clinical outcomes when used to treat both isthmic and degenerative spondylolisthesis. Although disk height restoration was more effective for IS than DS, other radiological parameters including fusion rate were no different between groups. For both isthmic and degenerative spondylolisthesis, MIS TLIF can be a safe and effective surgical option.

Current Evidence Regarding the Surgical and Nonsurgical Treatment of Pediatric Lumbar Spondylolysis: A Report from the Scoliosis Research Society Evidence-Based Medicine Committee

STUDY DESIGN

Structured literature review.

OBJECTIVES

The Scoliosis Research Society requested an assessment of the current state of peer-reviewed evidence regarding pediatric spondylolysis with the goal of identifying both what is really known and what research remains essential to further understanding.

SUMMARY OF BACKGROUND DATA

Spondylolysis is common among children and adolescents and no formal synthesis of the published literature regarding treatment has been previously performed.

METHODS

A comprehensive literature search was performed. The researchers reviewed abstracts and analyzed by committee data from included studies. From 947 initial citations with abstract, 383 articles underwent full text review. The best available evidence for clinical questions regarding surgical and nonsurgical treatment was provided by 58 included studies. None of the studies were graded as level I or level II evidence. Two of the studies were graded as level III evidence. Fifty-six of the studies were graded as level IV evidence. No level V (expert opinion) studies were included in the final list.

RESULTS

Although natural history studies suggest a benign, relatively asymptomatic course for spondylolysis in most patients, both nonsurgical and surgical treatment series suggest that a substantial number of patients present with pain and activity limitations attributed to spondylolysis. Pain resolution and return to activity are common with both nonsurgical and surgical treatment (80% to 85%, respectively). Although it is implied that most surgically treated patients have failed nonsurgical treatment, the specific treatment modalities and duration required before failure is declared are not well defined. There is insufficient evidence to know which patients will benefit from specific treatment modalities (both nonsurgical and surgical).

CONCLUSIONS

Because of the preponderance of uncontrolled case series and the lack of comparative studies, only low-quality evidence is available to guide the treatment of pediatric spondylolysis.

Comparison of functional outcomes following surgical decompression and posterolateral instrumented fusion in single level low grade lumbar degenerative versus isthmic spondylolisthesis

Background

The two most common types of surgically treated lumbar spondylolisthesis in adults include the degenerative and isthmic types. The aim of this study was to compare the functional outcomes of surgical decompression and posterolateral instrumented fusion in patients with lumbar degenerative and isthmic spondylolisthesis.

Methods

In this retrospective study, we reviewed the clinical outcomes in surgically treated patients with single level, low grade lumbar degenerative, and isthmic spondylolisthesis (groups A and B, respectively) from August 2007 to April 2011. We tried to compare paired settings with similar initial conditions. Group A included 52 patients with a mean age of 49.2 ± 6.1 years, and group B included 52 patients with a mean age of 47.3 ± 7.4 years. Minimum follow-up was 24 months. The surgical procedure comprised neural decompression and posterolateral instrumented fusion. Pain and disability were assessed by a visual analog scale (VAS) and the Oswestry Disability Index (ODI), respectively. The Wilcoxon and Mann-Whitney U-tests were used to compare indices.

Results

The most common sites for degenerative and isthmic spondylolisthesis were at the L4-L5 (88.5%) and L5-S1 (84.6%) levels, respectively. Surgery in both groups significantly improved VAS and ODI scores. The efficacy of surgery based on subjective satisfaction rate and pain and disability improvement was similar in the degenerative and isthmic groups. Notable complications were also comparable in both groups.

Conclusions

Neural decompression and posterolateral instrumented fusion significantly improved pain and disability in patients with degenerative and isthmic spondylolisthesis. The efficacy of surgery for overall subjective satisfaction rate and pain and disability improvement was similar in both groups.

Changes in spino-pelvic alignment after surgical treatment of isthmic spondylolisthesis

BACKGROUND AND PURPOSE

To analyze the changes in spino-pelvic parameters after surgical treatment of lumbar isthmic spondylolisthesis.

MATERIALS AND METHODS

Sixty patients recruited from a group of consecutive series of 128 cases with isthmic spondylolisthesis operated on between 2002 and 2012 in the Department of Neurosurgery, Tarnow, Poland. All patients were operated on by the same surgeon (the first author). Spino-pelvic parameters: PI, SS, PT, LSA, and LL were measured manually on standing lateral view radiograms. Patients were divided according to Spinal Deformity Study Group classification which we modified for means of analysis: (A) low-grade group: subgroups with balanced pelvis and unbalanced pelvis (instead of normal and high PI subgroups), (B) high-grade group: subgroups with balanced and unbalanced pelvis.

RESULTS

Twenty-nine patients had unbalanced pelvis before the operation. In 10 of them (34%), the procedure resulted in full correction of pelvis position meaning that they achieved balanced pelvis after the surgery. There were 6 patients with low-grade slip who had balanced pelvis preoperatively but showed unbalanced pelvis after the surgery but this loss of balanced pelvis did not affect the clinical outcome which overall was good among them. Patients with unbalanced pelvis presented changes towards restoration of spino-sacro-pelvic anatomy postoperatively: PT decreased while SS increased, although these changes were not statistically significant.

CONCLUSION

Further studies are needed to confirm whether surgical correction of spino-pelvic parameters results in better clinical outcome in patients with isthmic spondylolisthesis.

Difference of Sagittal Spinopelvic Alignments between Degenerative Spondylolisthesis and Isthmic Spondylolisthesis

Objective

The purpose of this study was to analyze the differences of spinopelvic parameters between degenerative spondylolisthesis (DSPL) and isthmic spondylolisthesis (ISPL) patients.

Methods

Thirty-four patients with DSPL and 19 patients with ISPL were included in this study. Spinopelvic parameters were evaluated on whole spine X-rays in a standing position. The following spinopelvic parameters were measured : pelvic incidence (PI), sacral slope, pelvic tilt (PT), lumbar lordosis (LL), and sagittal vertical axis from C7 plumb line (SVA). The population of patients was compared with a control population of 30 normal and asymptomatic adults.

Results

There were statistically significant differences in LL (p=0.004) and SVA (p=0.005) between the DSPL and ISPL group. The LL of DSPL (42±13°) was significantly lower than that of the control group (48±11°; p=0.029), but that of ISPL (55±6°) was significantly greater than a control group (p=0.004). The SVA of DSPL (55±49 mm) was greater than that of a control group (<40 mm), but that of ISPL (21±22 mm) was within 40 mm as that of a control group. The PT of DSPL (24±7°) and ISPL (21±7°) was significantly greater than that of a control group (11±6°; p=0.000).

Conclusion

Both symptomatic DSPL and ISPL patients had a greater PI than that of the asymptomatic control group. In conclusion, DSPL populations are likely to have global sagittal imbalance (high SVA) compared with ISPL populations because of the difference of lumbar lordosis between two groups.

Correlation of pelvic parameters with isthmic spondylolisthesis

STUDY DESIGN

A retrospective radiological evaluation.

PURPOSE

To verify that PI is related with progression of IS as well as development of IS and to assess the differences of pelvic parameters between the L4 & L5 IS, as well as between single & two level IS.

OVERVIEW OF LITERATURE

High pelvic incidence (PI) has been known to be related with development of IS. However, the previous studies were limited to just L5 spondylolisthesis or there was no differentiation between L4 & L5 spondylolisthesis

METHODS

Sixty five IS patients and 30 persons as a control group participated the study. Among the 65 patients, 30 had L4 IS, 30 had L5 IS and 5 had bi-level IS. We used the whole spine lateral radiographs to measure the slip percentage, the pelvic tilt (PT) and the pelvic incidence (PI), and we compared them between the normal control group and the IS patients, as well as between single-level and bi-level spondylolisthesis, and we investigated the correlation between the degree of slip of spondylolisthesis and the pelvic parameters.

RESULTS

The averages of the PT, PI and lumbar lordosis (LL) in the control group and the IS group were 11.0 degrees vs 21.4 degrees (p<0.001), 49.1 degrees vs 61.8 degrees (p<0.001) and 48.5 degrees vs 57.6 degrees (p<0.001), respectively. On comparison between the L4 and L5 IS groups, there was no difference in all the pelvic parameters (p>0.05). On comparison between the single-level IS group and the bilevel IS group, there was a significant difference of the PT and PI (p<0.05), and the slip percentage had a correlation with only the PI among all the pelvic parameters (Spearman's r=0.293, p=0.023). There was a significant correlation of the degree of slip with the PI for the L5 single level IS, but not with the L4 single level IS (r=0.362, p=0.05).

CONCLUSIONS

The high pelvic incidence can be a factor of L4 & L5 spondylolysis and it may have an influence on the slip progression in patients with L5 isthmic spondylolisthesis, but not on the slip progression in patients with L4 IS. Yet other factors seem to have an influence on the slip progression in patients with L4 isthmic spondylolisthesis.