Sagittal alignment in lumbosacral fusion: relations between radiological parameters and pain

Effectiveness of intraoperative table modification for achieving lumbar lordosis in multilevel lumbar fusion surgery: a propensity score-matched study

BACKGROUND

In multilevel posterior lumbar interbody fusion (PLIF) with posterior screw fixation, obtaining sufficient lumbar lordosis (LL) is difficult, especially in patients with osteoporosis. We performed intraoperative table modification (TM) using gravitational dropping of the patient's lumbar spine, to improve restoration of LL.

METHODS

We retrospectively reviewed the medical records of patients who underwent three- or four-level PLIF between 2005 and 2019. One hundred eleven patients were enrolled, with 96 patients receiving non-TM-PLIF and 15 patients receiving TM-PLIF. Radiological parameters, including segmental lordosis (SL), LL, sacral slope (SS), pelvic incidence, and pelvic tilt, were measured. Clinical outcomes were measured using a visual analogue scale (VAS) for the back and leg preoperatively and at the last follow-up. Additionally, the correlation between the bone mineral density (BMD) and the radiological parameters was calculated for TM-PLIF. We performed propensity score matching between the groups to control the baseline difference.

RESULTS

We found a statistically better correction between immediate and last follow-up postoperative SL (p = 0.04), as well as between preoperative and last follow-up SL (p < 0.01) in the TM-PLIF group compared to that in the non-TM-PLIF group. VAS for the back and leg were not significantly different between the two groups. Additionally, the efficacy of lordosis correction in the TM-PLIF group showed a statistically significant negative correlation between BMD and the SS change both before and after the surgery (rho = -0.60, p = 0.02).

CONCLUSION

Whilst further study is required to conclusively establish its efficacy, TM-PLIF (table modification using gravitational dropping) shows potential advantages for restoring and maintaining LL in multilevel lumbar fusion, particularly in cases with low BMD.

The role of the lower extremity on patient's cone of economy: an innovative approach

PURPOSE

To evaluate the effect of the lower extremities on cone of economy (CoE) calculations as well as to propose a novel assessment of seated balance using traditional CoE measurements.

METHODS

36 controls and 82 degenerative lumbar disease (LD) patients, (38 patients with unilateral radiculopathy (UR), 44 patients with neurogenic claudication (NC) with bilateral symptoms), were enrolled in the study. Functional balance tests were performed and recorded by 3D motion capture in both the standing (Romberg) and seated positions. Balance effort and CoE dimensions were calculated.

RESULTS

The lower extremities exert a significant impact on balance, as reflected in the total head (UR: 20.9, NC: 31.5 vs. H: 10.0 cm, p < 0.015), pelvis (UR: 73.2, NC: 110.0 vs. H: 36.4 cm, p < 0.002) and CoM (UR: 17.1, NC: 18.7 vs. H: 4.6 cm, p < 0.001) sway differences observed between LD patients and healthy controls. Significant differences in CoE dimensions were observed as captured by sagittal head (UR: 2.8 vs. H: 0.9 cm, p = 0.014) and pelvis (UR: 2.8 vs. H: 1.4 cm, p = 0.019) range of sway (RoS) and coronal pelvic RoS (UR: 1.1, NC: 1.1 vs. H: 0.6 cm, p < 0.012) between LD patients and healthy controls.

CONCLUSION

This study first provides a novel standardized means of isolating and quantifying the role of the lower extremity on the CoE in patients with LD, which highlights how spinal pathologies may directly impact and/or contribute to compensatory mechanisms in this region. As evidenced by 18.0-93.2 cm of total sway and 1.1-2.8 cm RoS, the lower extremities account for a significant amount of balance effort and CoE dimensions.

The role of pelvic coronal parameters in determining sagittal balance: a prospective radiographic analysis of pelvic spinopelvic alignment in Chinese asymptomatic Han adolescents

Background

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional spinal deformity where sagittal alignment significantly influences clinical outcomes. This study aims to analyze spinopelvic balance parameters in asymptomatic adolescents without scoliosis, examining the correlation between pelvic coronal parameters and sagittal balance parameters to validate their use as preliminary indicators in assessing pelvic rotation.

Methods

A prospective study was conducted involving 354 adolescents (199 females, 155 males) aged 6-18 years who underwent full-length anteroposterior (AP) and lateral spine radiographs at The Third Hospital of Hebei Medical University between October 2022 and December 2023. Ethical approval and informed consent were obtained. Radiographic assessments included measuring pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), pelvic sacral angle (PSA), and other related parameters. Statistical analysis was performed using SPSS software.

Results

Significant gender differences were observed in Risser sign distribution and pelvic tilt, with females exhibiting more advanced skeletal maturity. Positive correlations were found between pelvic incidence and pelvic tilt (r = 0.41), and pelvic incidence and sacral slope (r = 0.57), while negative correlations were noted between pelvic incidence and pelvic sacral angle (r = -0.43). Strong correlations between sagittal parameters and newly introduced coronal parameters, such as sacral-femoral-pubic angle and Pubo-Hilgenreiner Distance, were also identified.

Conclusion

The study demonstrates that parameters like Iliac tilt, Pelvic sacral angle, Sacral-femoral-pubic angle, and Pubo-Hilgenreiner Distance correlate well with traditional spinopelvic parameters and can be used to assess pelvic sagittal balance in clinical settings. Future research should focus on longitudinal studies to further validate these findings.

L5 osteotomy combined with adjuvant romosozumab therapy for L5 osteoporotic vertebral fracture-induced spinal deformity: illustrative case

BACKGROUND

Spinal reconstruction of an L5 osteoporotic vertebral fracture (OVF) is a demanding surgery because of the condition's rarity, poor bone quality, and anatomical reasons. To date, there has been little debate regarding the surgical strategy for L5 OVF and effective osteoporosis treatment. The authors report L5 osteotomy and adjuvant romosozumab (ROMO) therapy for L5 OVF-induced spinal deformity.

OBSERVATIONS

A 73-year-old woman underwent lumbopelvic instrumentation and fusion from L3 to the pelvis, L5 osteotomy combined with unilateral posterior vertebral column resection (VCR), followed by expandable cage replacement and bone biopsy simultaneously. Histomorphometric analysis of the bone biopsy showed accelerated bone formation in the endocortical region of the spinous process. After surgery, her low back pain and leg pain improved with satisfactory global alignment. At the 2-year follow-up, lumbopelvic reconstruction achieved fusion, with minimal reciprocal change and no mechanical failure. The patient's Oswestry Disability Index improved from 64% to 24%. L5 osteotomy combined with unilateral VCR and expandable cage replacement was a safe and effective technique in this case.

LESSONS

This technique can provide both greater restoration of lower lumbar lordosis and pelvic tilt with fusion. Moreover, adjuvant ROMO therapy has the potential to prevent osteoporosis-related complications. https://thejns.org/doi/10.3171/CASE24633.

Effect of Approach Based Lumbar Interbody Fusion on Sagittal Spinopelvic Parameters and Functional Outcomes: Comparison between Oblique Lumbar Interbody Fusion (OLIF) and Transforaminal Lumbar Interbody Fusion (TLIF)

PURPOSE

Transforaminal lumbar interbody fusion (TLIF) and oblique lumbar interbody fusion (OLIF) are the most commonly conducted operations for interbody fusions. In addition to fusion, the restoration of proper spinal alignment has become crucial for achieving favorable functional outcomes. There is a lack of agreement on which lumbar interbody fusion technique provides the most effective correction for sagittal spinopelvic parameters (SSPs). This study aims to investigate the functional outcome in terms of SSPs in patients undergoing single level OLIF and TLIF for lumbar degenerative disc disease.

METHODOLOGY

Retrospective analysis of single level OLIF or TLIF was done. The patients' index and follow-up data until 6 months of surgery were collected. Radiographic parameters analysis included disc height (DH), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), pelvic index, lumbar lordosis (LL), segmental lordosis (SL). Clinical outcomes were recorded using visual analogue scale (VAS) and Oswestry Disability Index (ODI).

RESULTS

In a total of 38 patients (19 in each group) mean age was 51.52 ± 12.67 years in OLIF and 52.17 ± 9.73 years in TLIF. Improvement in DH was more in OLIF but not statistically significant (p = 0.075). Significant improvements were seen in PT, and SL post-TLIF. Change in SSPs among groups shown no significant differences. Both VAS and ODI shown improvements in both the groups but no significant difference was noted while comparing the two groups.

CONCLUSION

The study showed better restoration of SSPs by TLIF in terms of PT and SL although functional outcomes appear similar in both procedures. Increase in DH is the important determinant for resulting good outcome. Patients with maintained spinopelvic balance can be treated satisfactorily with less-invasive OLIF.

Sacroiliac Joint: Function, Pathology, Treatment, and Contribution to Outcomes in Spine and Hip Surgery

➢ Low back pain has a lifetime incidence of up to 84% and represents the leading cause of disability in the United States; 10% to 38% of cases can be attributed to sacroiliac joint (SIJ) dysfunction as an important pain generator.➢ Physical examination of the SIJ, including >1 provocation test (due to their moderate sensitivity and specificity) and examination of adjacent joints (hip and lumbar spine) should be routinely performed in all patients presenting with low back, gluteal, and posterior hip pain.➢ Radiographic investigations including radiographs, computed tomography, and magnetic resonance imaging with protocols optimized for the visualization of the SIJs may facilitate the diagnosis of common pathologies.➢ Intra-articular injections with anesthetic can be helpful in localizing the source of low back pain. Over-the-counter analgesics, physiotherapy, intra-articular injections, radiofrequency ablation, and surgery are all management options and should be approached from the least invasive to the most invasive to minimize the risks of complications.➢ Lumbar fusion surgery predisposes patients to more rapid SIJ degeneration and can also result in more rapid degenerative changes in the hip joints, especially with SIJ fusion.➢ Hip surgery, including hip arthroplasty and preservation surgery, is not a risk factor for SIJ degeneration, although reduced outcomes following hip surgery can be seen in patients with degenerative SIJ changes.

Does physical performance demonstrate patient-reported outcomes after lumbar spine surgery?

BACKGROUND

Due to time and setting constraints in clinical practice, performing a comprehensive assessment with both questionnaires and physical performance tests may not be possible. This study aimed to demonstrate the relationship between physical performance and patient-reported outcomes in patients after Lumbar Spine Surgery (LSS).

METHODS

A cross-sectional study was conducted with 50 participants who were followed up at least six months after LSS. Participants were evaluated using the Visual Analog Scale (VAS) for activity and rest, Modified Oswestry Disability Index (mODI), Lumbar Spine Instability Questionnaire (LSIQ), One Leg Stance Test (OLST), Semi-Tandem Stance Test (STST), 4 m Gait Speed Test (4MGS), and Timed Up and Go Test (TUG).

RESULTS

OLST was moderately correlated with the mODI (r=-0.442, p < 0.01). STST moderately correlated with mODI (r=-0.356, p < 0.05). TUG was strongly correlated with mODI (r = 0.564, p < 0.01). In addition, TUG showed a moderate correlation with a-VAS and LSIQ, respectively (r1 = 0.392, r2 = 0.475, p < 0.01). A strong correlation was found between 4MGS and mODI (r=-0.535, p < 0.01). 4MGS had a moderate correlation with LSIQ (r=-0.374, p < 0.01). A regression model summary showed that the TUG, OLST, and STST were not related to r-VAS, a-VAS, mODI, and LSIQ (p > 0.01). Higher gait speed on the 4MGS test was strongly associated with lower mODI scores (standardized ß=-0.538, p = 0.021).

CONCLUSION

Less activity pain and disability are associated with good balance and performance. 4MGS can mostly predict patient-reported function in patients after LSS.

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

STUDY DESIGN

Systematic review and meta-analysis of literature.

OBJECTIVE

The aim of the presented study is to assess whether the reduction of high-grade spondylolisthesis (HGS) through the correction of lumbosacral kyphosis leads to a decrease in the sagittal spinopelvic compensatory mechanisms.

SUMMARY OF BACKGROUND DATA

HGS is as an anterior translation of a vertebra, >50%. It is also characterized by a kyphotic deformity of the affected level. This combination of translation and kyphosis leads to compensatory mechanisms on the sagittal plane [pelvic retroversion, increased lumbar lordosis (LL), reduction in thoracic kyphosis (TK)].

METHODS

A systematic search of electronic databases was conducted. Inclusion criteria were diagnosis of HGS (Meyerding >II, Slip% >50%), partial or complete reduction surgery (with a significant decrease in Slip%), and report of spinopelvic parameters (pelvic incidence, pelvic tilt, or sacral slope). Clinical and radiographic outcomes were extracted and summarized. Meta-analyses were performed to estimate the differences between preoperative and postoperative spinopelvic alignment measures. P <0.05 was considered significant.

RESULTS

Eighteen studies were included. PT showed a statistically significant decrease of -2.1217 (95% CI: -3.4803 to -0.7630), while SS showed a significant increase of 4.8349 (95% CI: 2.7462-6.9236). Conversely, both LL and TK showed nonsignificant changes, -4.7043 (95% CI: -10.4535 to 1.0449) and 6.3881 (95% CI: -0.8344 to 13.6106), respectively. VAS significantly decreased by -3.1950 (95% CI: -4.9462 to -1.4439).

CONCLUSIONS

The meta-analysis showed mild, yet statistically significant, decrease of PT and an increase in SS after HGS reduction. Conversely, nonstatically significant decrease in LL and an increase in TK occurred. The clinical significance of these results remains questionable.

LEVEL OF EVIDENCE

Level IV.

Can pelvic incidence affect changes in sagittal spino-pelvic parameters between standing and sitting positions in individuals with lumbar degenerative disease?

OBJECTIVE

The aim of this study was to explore the correlation between PI and standing-to-sitting changes of the sagittal alignment in patients with lumbar degenerative diseases, and investigate the differences in posture changes among Roussouly types.

METHODS

A total of 209 patients with lumbar degenerative disease were retrospectively included in this study. All the patients received lateral full body imaging in both standing and sitting positions. Sagittal parameters including SVA, OD-HA, PT, PI, PT/PI, SS, LL, TK, Upper LL (L1-L4) and Lower LL (L4-S1) were measured in both standing and sitting position, and the parameters were compared between two positions. The correlations between PI and lumbo-pelvic changes were analyzed. The postural changes were compared among different Roussouly types.

RESULTS

From standing to sitting, all the parameters except PI significantly changed, including SVA, OD-HA, PT, PT/PI, SS, LL, TK, Upper LL and Lower LL. The contribution of lower LL was greater to global LL than upper LL. PI had a significant correlation with ΔPT, ΔSS, ΔLL, ΔUpper LL and ΔLower LL. From standing to sitting, type 4 patients had the most pronounced ΔPT, ΔSS and ΔLL, and ΔLower LL of types 3 and 4 were greater than that of types 1 and 2.

CONCLUSIONS

In patients with degenerative disease, PI plays an important role in determining the extent of lumbo-pelvic changes from standing to sitting. Among different Roussouly types, type 4 patients have the most pronounced changes of PT, SS and LL, suggesting the relatively greater flexibility of pelvis and lumbar spine.

Effect of Lumbar Spinal Stabilization Exercises Along With Neural Tissue Mobilization on Pain and Spinal Dysfunction in Failed Back Surgery Syndrome

Background Failed back surgery syndrome (FBSS) mainly involves back pain radiating to the lower limb after back-related surgeries. It can develop various complications around the operation site and its surrounding area. This study evaluates the effect of lumbar spinal stabilization exercises and neural tissue mobilization on pain and spinal dysfunction in FBSS. Objectives To study the impact of lumbar spinal stabilization exercises and neural tissue mobilization on pain and spinal dysfunction in FBSS. To compare the impact of lumbar spinal stabilization exercises and neural tissue mobilization with conventional therapy on pain and spinal dysfunction in FBSS. Methods The study included 76 participants aged 45-60 with back pain radiating to lower limbs after back-related surgeries within the past six months. Participants were randomly assigned to either a conventional treatment group (Group A) or an experimental exercise program group (Group B). The treatment duration was six weeks and data were analyzed by a paired t-test for within-group analysis and an unpaired t-test for between-group analysis. Results Both groups A and B showed significant differences in all three outcome measures. However, Group B showed extremely significant improvement (<0.0001) in outcome measures, including pain, lumbar muscle strength by manual muscle testing, and modified Oswestry index assessment compared to Group A. Conclusion Both conventional and experimental groups showed a significant impact on the pain and level of function in failed back surgery syndrome patients. However, lumbar stabilization exercises along with neural tissue mobilization (Group B) showed a more pronounced impact on all outcomes such as pain reduction and improvement in lumbar flexor, rotator, and extensor muscle strength and modified Oswestry index compared to the conventional treatment group (Group A).

Sacroiliac pain after total hip arthroplasty: a combined analysis of clinical data and three-dimensional imaging in standing and sitting positions

PURPOSE

Patients frequently complain of low back pain and sacroiliac joint pain (SIP) following total hip arthroplasty (THA). We hypothesized that patients with SIP would display different pelvic incidence (PI) values between standing and relaxed sitting positions, indicative of increased motion in the sacroiliac joints.

METHODS

In this retrospective case-control study, 94 patients who underwent unilateral THA and experienced SIP were compared with 94 control patients without SIP. SIP was confirmed through clinical tests and investigated using biplanar imaging in both standing and sitting positions. The key parameters analyzed included PI, sacral slope (SS), lumbar lordosis (LL), and limb length discrepancy (LLD).

RESULTS

Patients without SIP showed a mean difference in PI of -1.5° (-8°-5°) between standing-to-sitting positions, whereas those with SIP showed a difference of -3.3° (-12°-0°)(P < 0.0001), indicating more motion in the sacroiliac joint during daily activities in the latter group. Patients with SIP showed smaller change in LL between standing-to-sitting positions (mean:6.3°; range:-8°-27°) compared with those without SIP (mean:9.5°; range:-12°-28°)(P = 0.006). No significant differences were noted in functional leg length between patients with (mean:7 mm; range:0-12 mm) and without SIP (mean:7 mm; range:0-11 mm)(P = 0.973).

CONCLUSIONS

This study revealed significant sacroiliac joint motion in patients with SIP post-THA, as indicated by PI changes, increased posterior pelvic tilt, and reduced change in the LL. Contrary to common belief, SIP did not correlate with LLD.

The L3 Flexion Angle Predicts Failure of Non-Operative Management in Patients with Tandem Spondylolithesis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Determine impact of standard/novel spinopelvic parameters on global sagittal imbalance, health-related quality of life (HRQoL) scores, and clinical outcomes in patients with multi-level, tandem degenerative spondylolisthesis (TDS).

METHODS

Single institution analysis; 49 patients with TDS. Demographics, PROMIS and ODI scores collected. Radiographic measurements-sagittal vertical axis (SVA), pelvic incidence (PI), lumbar lordosis (LL), PI-LL mismatch, sagittal L3 flexion angle (L3FA) and L3 sagittal distance (L3SD). Stepwise linear multivariate regression performed using full length cassettes to identify demographic and radiographic factors predictive of aberrant SVA (≥5 cm). Receiver operative curve (ROC) analysis used to identify cutoffs for lumbar radiographic values independently predictive of SVA ≥5 cm. Univariate comparisons of patient demographics, (HRQoL) scores and surgical indication were performed around this cutoff using two-way Student's t-tests and Fisher's exact test for continuous and categorical variables, respectively.

RESULTS

Patients with increased L3FA had worse ODI (P = .006) and increased rate of failing non-operative management (P = .02). L3FA (OR 1.4, 95% CI) independently predicted of SVA ≥5 cm (sensitivity and specifity of 93% and 92%). Patients with SVA ≥5 cm had lower LL (48.7 ± 19.5 vs 63.3 ± 6.9 mm, P < .021), higher L3SD (49.3 ± 12.9 vs 28.8 ± 9.2, P < .001) and L3FA (11.6 ± 7.9 vs -3.2 ± 6.1, P < .001) compared to patients with SVA ≤5 cm.

CONCLUSIONS

Increased flexion of L3, which is easily measured by the novel lumbar parameter L3FA, predicts global sagittal imbalance in TDS patients. Increased L3FA is associated with worse performance on ODI, and failure of non-operative management in patients with TDS.

Predictability in Achieving Target Intervertebral Lordosis Using Personalized Interbody Implants

BACKGROUND

Lumbar lordosis distribution has become a pivotal factor in re-establishing the foundational alignment of the lumbar spine. This can directly influence overall sagittal alignment, leading to improved long-term outcomes for patients. Despite the wide availability of hyperlordotic stock cages intended to achieve optimal postoperative alignment, there is a lack of correlation between the lordotic shape of a cage and the resultant intervertebral alignment. Recently, personalized spine surgery has witnessed significant advancements, including 3D-printed personalized interbody implants, which are customized to the surgeon's treatment and alignment goals. This study evaluates the reliability of 3D-printed patient-specific interbody implants to achieve the planned postoperative intervertebral alignment.

METHODS

This is a retrospective study of 217 patients with spinal deformity or degenerative conditions. Patients were included if they received 3D-printed personalized interbody implants. The desired intervertebral lordosis (IVL) angle was prescribed into the device design for each personalized interbody (IVL goal). Standing postoperative radiographs were measured, and the IVL offset was calculated as IVL achieved minus IVL goal.

RESULTS

In this patient population, 365 personalized interbodies were implanted, including 145 anterior lumbar interbody fusions (ALIFs), 99 lateral lumbar interbody fusions (LLIFs), and 121 transforaminal lumbar interbody fusions. Among the 365 treated levels, IVL offset was 1.1° ± 4.4° (mean ± SD). IVL was achieved within 5° of the plan in 299 levels (81.9%). IVL offset depended on the approach of the lumbar interbody fusion and was achieved within 5° for 85.9% of LLIF, 82.6% of transforaminal lumbar interbody fusions and 78.6% of ALIFs. Ten levels (2.7%) missed the planned IVL by >10°. ALIF and LLIF levels in which the plan was missed by more than 5° tended to be overcorrected.

CONCLUSIONS

This study supports the use of 3D-printed personalized interbody implants to achieve planned sagittal intervertebral alignment.

CLINICAL RELEVANCE

Personalized interbody implants can consistently achieve IVL goals and potentially impact foundational lumbar alignment.

LEVEL OF EVIDENCE: 4

Changes in Alignment at Untreated Vertebral Levels Following Short-Segment Fusion Using Personalized Interbody Cages: Leveraging Personalized Medicine to Reduce the Risk of Reoperation

BACKGROUND

An abnormal postoperative lordosis distribution index (LDI), which quantifies the ratio between the lordosis at L4 to S1 and the lordosis at L1 to S1, contributes to the development of adjacent segment disease and increased revision rates in patients undergoing short-segment lumbar intervertebral fusions. Incorporating preoperative spinopelvic parameters and LDI into the surgical plan for short-segment fusion is important for guiding alignment restoration and preserving normal preoperative alignment in unfused segments. This study examined changes in LDI, segmental lordosis, and lordosis of the unfused levels in patients treated with personalized interbody cage (PIC) implants.

METHODS

This retrospective study evaluated radiographic measurements from 111 consecutively treated patients diagnosed with degenerative spinal conditions and treated with a short-segment fusion of L4 to L5, L5 to S1, or L4 to S1 using PIC implant(s) within 6 months of the fusion procedure. Comparisons of intervertebral lordosis for treated and untreated levels as well as LDI pre- and postoperatively were performed.

RESULTS

In patients with a preoperative hypolordotic distribution (LDI < 50%), statistically significant increases were found in LDI postoperatively, approaching the normal LDI range (LDI 50%-80%). Likewise, patients with hyperlordotic distribution preoperatively (LDI > 80%) experienced a decrease in LDI postoperatively, trending toward the normal range, although the changes were not statistically significant. Intervertebral lordosis for the L5 to S1 level increased significantly following the placement of a PIC in the normal and hypolordotic LDI groups. Changes in intervertebral lordosis for L5 to S1 were not significant for patients with preoperative hyperlordotic LDI. Reciprocal changes in intervertebral lordosis at L1 to L4 were not observed in any groups.

CONCLUSIONS

PIC implants may provide a benefit for patients, particularly those with hypolordotic distributions preoperatively. They have the potential to further improve patient outcomes by helping surgeons to achieve patient-specific lordosis goals, which may help to reduce the risk of adjacent segment disease and revisions in patients undergoing short-segment lumbar intervertebral fusions.

CLINICAL RELEVANCE

Personalized implants can help surgeons achieve patient-specific alignment goals, potentially prevent adjacent segment disease, and reduce long-term reinterventions.

LEVEL OF EVIDENCE: 4

Global sagittal angle and spinopelvic sagittal alignment: a step toward investigation of sagittal plane deformity in upper lumbar disc herniation

BACKGROUND AND OBJECTIVES

Understanding the biomechanical relationship between the spine and the pelvis is important for the management of symptomatic lumbar disease. There are several different metrics that may be used to evaluate the spine in the sagittal plane. The aim of this study is to compare spinopelvic parameters and global sagittal angle (GSA) in a cohort of patients with upper lumbar disc herniations (ULDH) to identify a correlation between the pelvic incidence (PI) and GSA with ULDH.

MATERIAL AND METHODS

Eighty-six patients with ULDH and 86 asymptomatic control group underwent whole body biplanar stereographs- and magnetic resonance imaging. The spinopelvic parameters and GSA were measured.

RESULTS

PI, sacral slope (SS), lumbar lordosis (LL), and thoracic kyphosis (TK) were all significantly lower than in the control group (p < 0.01) but there was no difference in the pelvic tilt (PT). The two groups were divided into subgroups. PI in the T12-L1 and L1-L2 level groups were significantly smaller than in the control group (p < 0.05). Also, there was a significant difference in TK and LL between the L3-L4 level and control group (p < 0.05), but there was no statistically significant difference in PT between all levels and the control group.

CONCLUSION

This study demonstrated a unique correlation between several spinopelvic parameters and GSA and the occurrence of ULDH. Lower PI, SS, and LL in T12-L1 and L1-L2 levels indicates a flat lumbar spine which may increase mechanical stress at these levels, thereby leading to disc herniation.

[Sagittal Profi le of the Spine in Patients after Lumbar Stabilisation Surgeries]

PURPOSE OF THE STUDY

Spine stabilization surgery is nowadays one of the most common spinal surgical procedures. Spinopelvic alignment is considered to be an important factor impacting the patients' preoperative diffi culties as well as the outcome of surgery. In our study, the outcomes of stabilization surgeries in patients with lumbar spine disorders were evaluated - especially in those with stenosis and spondylolisthesis, in whom the importance of sagittal parameters were assessed with respect to the patients' clinical outcomes and diffi culties.

MATERIAL AND METHODS

The study included 50 patients with lumbar spine disorders who had undergone a spine stabilization surgery for a degenerative disease - lumbar spinal stenosis, spondylolisthesis between 2015 and 2017. Spino-pelvic radiological parameters and clinical parameters were evaluated using the nonparametric Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests.

RESULTS

In 38 of 50 patients, who at the end of the follow-up period did not have the PI-LL (pelvic incidence-lumbar lordosis) mismatch, i.e. PI-LL was ≤10°, a statistically signifi cant difference in pelvic tilt (p=0.049) and sagittal vertical axis (p<0.001) was reported, which was not the case in the remaining patients of the study population. Claudication and OSWESTRY (ODI) showed no statistically signifi cant difference. We have also compared the differences in the number of fused vertebrae and type of stabilization. A signifi cant change was seen in the claudication parameter at 12 and 24 months after surgery (p=0.007, p=0.005), with better outcomes achieved by 360° lumbar fusion compared to posterior lumbar fusion. The improvement of VAS and ODI scores in both the groups over time (from 6.1 to 3.6 or from 6.3 to 3.5 in VAS and from 62 to 32, or from 62 to 30 in ODI) was also statistically signifi cant (p<0.001 in both groups), while when comparing the groups against each other it was statistically insignifi cant.

DISCUSSION

The authors confi rmed signifi cant improvement in the studied clinical parameters in all groups of patients (VAS, ODI, claudication), which is consistent with the results of recently published papers. The authors also established the correlation between different radiological parameters in the studied groups. The results do not confi rm the importance of the length or type of instrumentation for the clinical outcomes. This is consistent with the fi ndings of other published manuscripts. The authors failed to confi rm a signifi cant change in clinical parameters in dependence on the matching relationship between the pelvic incidence and lumbar lordosis.

CONCLUSIONS

Proper spinopelvic balance in patients after spinal surgery is a very important indicator of postoperative development and condition, but our cohort showed no statistically signifi cant difference in the clinical outcomes of patients whose postoperative sagittal parameters were unsatisfactory.

KEY WORDS

sagittal profi le, spine stabilization, pelvic tilt, pelvic incidence, sagittal vertical axis, SVA.

Clinical and radiographic outcomes following correction of idiopathic scoliosis in adolescence vs young adulthood

PURPOSE

The natural history of adolescent idiopathic scoliosis (AIS) has been well documented, but the impact of age at the time of surgical correction is relatively understudied. In this study, we matched patients undergoing surgical correction of adult idiopathic scoliosis (AdIS) with a cohort of AIS patients to compare: (1) coronal and sagittal radiographic correction, (2) operative variables, and (3) postoperative complications.

METHODS

A single-institution scoliosis registry was queried for patients undergoing idiopathic scoliosis surgery from 2000-2017.

INCLUSION CRITERIA

patients with idiopathic scoliosis, no previous spine surgery, and 2-year follow-up. AdIS patients were matched 1:2 with AIS patients based on Lenke classification and curve characteristics. Independent sample t-test and Chi-square test was used to analyze the data.

RESULTS

31 adults underwent surgical correction of idiopathic scoliosis and were matched with 62 adolescents. Mean age of adults was 26.2 ± 11.05, mean BMI was 25.6 ± 6.0, and 22 (71.0%) were female. Mean age of adolescents was 14.2 ± 1.8, mean BMI was 22.7 ± 5.7, and 41(66.7%) were female. AdIS had significantly less postoperative major Cobb correction (63.9% vs 71.3%, p = 0.006) and final major Cobb correction (60.6% vs 67.9%, p = 0.025). AdIS also had significantly greater postoperative T1PA (11.8 vs 5.8, p = 0.002). AdIS had longer operative times (p = 0.003), higher amounts of pRBCs transfused (p = 0.005), longer LOS (p = 0.016), more ICU requirement (p = 0.013), higher overall complications (p < 0.001), higher rate of pseudarthrosis (p = 0.026), and more neurologic complications (p = 0.013).

CONCLUSION

Adult patients undergoing surgical correction of idiopathic scoliosis had significantly worse postoperative coronal and sagittal alignment when compared with adolescent patients. Adult patients also had higher rates of complications, longer operative times, and longer hospital stays.

LEVEL OF EVIDENCE

III.

Measuring Outcomes in Spinal Deformity Surgery

Outcome assessment in adult spinal deformity has evolved from radiographic analysis of curve correction to patient-centered perception of health-related quality-of-life. Oswestry Disability Index and the Scoliosis Research Society-22 Patient Questionnaire are the predominantly used patient-reported outcome (PRO) measurements for deformity surgery. Correction of sagittal alignment correlates with improved PRO. Functional outcomes and accelerometer measurements represent newer methods of measuring outcomes but have not yet been widely adopted or validated. Further adoption of a minimum set of core outcome domains will help facilitate international comparisons and benchmarking, and ultimately enhance value-based healthcare.

Evaluation of lordosis recovery after lumbar arthrodesis and its clinical impact

BACKGROUND

Posterior lumbar arthrodesis has become a widely used therapeutic option to correct sagittal imbalances in patients suffering from degenerative lumbar conditions. However, in western Africa, there is no study have reported long-term outcome of posterior lumbar arthrodesis. The aim of this study was to investigate the relationship between the restoration of adequate lordosis and the patient's postoperative quality of life.

METHOD

The study was retrospective. From January 2012 to December 2019, 80 patients who underwent posterior lumbar arthrodesis for lumbar degenerative diseases were included with a mean follow-up of 43.2 months. Mean age was 50.8 years (SD = 12.2). Preoperative and postoperative patients' symptoms were assessed by the visual analog scale (VAS), Oswestry Disability Index (ODI), and 12-item Short Form (SF-12). Pre- and post-operative radiographic evaluation included lumbar lordosis measured (LLm), pelvic incidence (PI), sacral slope (SS), and pelvic stilt (PS). Theoretical lumbar lordosis (LLt) was defined by the following: LL = 0.54 × PI + 27.6. Data analysis was done using the statistical software "R." The risk of error was 5% (p < 0.05).

RESULT

The mean pelvic incidence was 57.23°. There was no statistically significant difference between preoperative and postoperative lumbar lordosis (p = 0.2567). There was no statistical difference between preoperative and postoperative PI-LL (p = 0.179). There was a statistically significant difference between the pre and postoperative clinical scores (p < 0.001). Statistical analysis showed a correlation between recovery of lumbar lordosis and improvement in physical component of SF-12 (PCS) (p < 0.05) and lumbar and radicular VAS (p < 0.05) for the subgroup of narrow lumbar spine. There was a statistical relationship between the restoration of lumbar lordosis and improvement in PCS (p = 0.004) and VAS (p = 0.003) for the subgroup of isthmic lysis spondylolisthesis.

DISCUSSION

The root decompression performed in most patients could explain the clinical improvement regardless of recovery of lordosis. The failure to consider spinal parameters and sagittal balance of patients in the surgery could explain no restoration of lumbar lordosis. Our study had limitations inherent to its retrospective character such as the classic selection bias.

CONCLUSION

Satisfactory correction of spinopelvic alignment may improve long-term clinical signs.

Restore cervical sagittal alignment by cervical disc arthroplasty and systematic total bilateral uncuscectomy in severe spondylosis: A prospective study

Introduction

Severe spondylosis is common and represents contraindication to achieve cervical disc arthroplasty (CDA).

Research question

Is it possible to restore cervical sagittal alignment using an adequate prosthetic model and performing systematic bilateral total uncuscectomy (or uncinectomy), even in cases of severe spondylosis ?

Material and methods

We propose a prospective clinical and radiological study comparing the evolution of preoperative and postoperative cervical sagittal balance 1 year after the interposition of a prosthesis with mobile bearing and systematic total uncuscectomy. VAS for brachialgia and cervicalgia, NDI, Odom's criteria, C2-C7 Cobb angle, C2-C7 SVA, T1 slope, C2 slope, C1-C2 Cobb angle, and segmental Cobb angle were analyzed preoperatively and 1 year postoperatively.

Results

73 patients for a total of 129 levels treated were analyzed. Patients showed significant improvements in VASb, VASc, NDI, and Odom's criteria one year after surgery without clinical differences in the severe spondylosis subgroup (41 patients for 77 levels treated). Our results showed an increase in the C2-C7 Cobb angle postoperatively and a better correlation between T1 slope and C2-C7 Cobb angle postoperatively than preoperatively. Postoperative radiological results were similar between the spondylosis and non-spondylosis subgroups. However preoperative C2-C7 Cobb angle and preoperative ROM were lower in the severe spondylosis subgroup.

Discussion and conclusion

This study showed the possibility of restoring cervical sagittal balance by performing cervical disc arthroplasty with systematic uncuscectomy, even in cases of severe spondylosis. Moreover, we propose a simplified mathematical formula to preoperatively evaluate the lack of angulation to restore sagittal cervical alignment.

New Onset Sacroiliac Joint Pain After Transforaminal Interbody Fusion: What Are the Culprits?

STUDY DESIGN

A retrospective case-control study.

OBJECTIVE

Only a few studies have studied the incidence of new-onset SI joint pain following lumbar spine fusion surgery. We aimed to explore the association between new-onset SI joint pain following Transforaminal Lumbar Interbody Fusion (TLIF) for degenerative spine disorders and changes in spinopelvic parameters.

METHODS

A retrospective review of hospital records and imaging database of a tertiary care institute was done for patients who underwent TLIF from October 2018 to October 2019. The 354 patients who satisfied the eligibility criteria were divided into 2 groups(Group A, new-onset SI joint pain group, n = 34 and Group B, normal controls, n = 320). Symptomatic relief (>70% reduction in the VAS [Visual Analogue Scale] score) after 15 minutes of SI joint injection was considered diagnostic of SI joint pain. Clinical and radiological spinopelvic parameters were compared between the 2 groups.

RESULTS

Patients with postoperative SI joint pain (Group A) had significantly less preoperative and postoperative lumbar lordosis (p < 0.001) compared to the other group. Most of the patients in Group A had a cephalad migration of the apex postoperatively (30/34 patients) whereas majority of patients in group B had either predominant caudal migration (44/320 patients) or no migration of the lumbar apex (272/320 patients).

CONCLUSIONS

The preoperative and postoperative lumbar lordosis are significantly less and the postoperative pelvic tilt is significantly high in patients with new-onset SI joint pain compared to the control group. The cephalad migration of the lumbar apex is significantly associated with new-onset SI joint pain.

Lateral Lumbar Interbody Fusion Using Expandable vs Static Titanium Interbody Cages: A Prospective Cohort Study of Clinical and Radiographic Outcomes

BACKGROUND

Expandable cages are a recent development employed to reduce subsidence and improve fusion compared with static cages as they alleviate the need for repeated trialing or overdistraction of the disc space. This study aimed to compare the radiographic and clinical outcomes in patients undergoing lateral lumbar interbody fusion (LLIF) with either an expandable or static titanium cage.

METHODS

This was a prospective study of 98 consecutive patients undergoing LLIF performed over a 2-year period, with the first 50 patients receiving static cages and the following 48 receiving expandable cages. Radiographic evaluation included interbody fusion status, cage subsidence, and change in segmental lordosis and disc height. Clinical evaluation assessed patient-reported outcome measures (PROMs), including the Oswestry Disability Index, visual analog scale (VAS) for back and leg pain, and short form-12 physical and mental health survey scores collected at 3, 6, and 12 months postoperatively.

RESULTS

The 98 patients had 169 cages impacted (84 expandable vs 85 static). Mean age was 69.2 years, and 53.1% were women. There was no significant difference between the 2 groups in terms of age, gender, body mass index, or smoking status. The expandable cage group had higher rates of interbody fusion (94.0% vs 82.9%, P = 0.039) at 12 months as well as significantly reduced implant subsidence rates at all follow-up timepoints (4% vs 18% at 3 months; 4% vs 20% at 6 and 12 months). Patients from the expandable cage group showed a mean 1.9 more points of reduction in VAS back pain (P = 0.006) and 2.49 points greater reduction in VAS leg pain (P = 0.023) at 12-month follow-up.

CONCLUSIONS

Expandable lateral interbody spacers resulted in significantly improved fusion rates with reduced subsidence risks and statistically significant improvement in PROMs up to 12 months postoperatively compared with impacted lateral static cages.

CLINICAL RELEVANCE

The data provide clinical relevance in favoring expandable cages over static cages for enhanced fusion outcomes in lumbar fusions.

LEVEL OF EVIDENCE: 2

Relationship between lumbar lordosis, pelvic parameters, PI-LL mismatch and outcome after short fusion surgery for lumbar degenerative disease. Literature review, rational and presentation of public study protocol: RELApSE study (registry for evaluation of lumbar artrodesis sagittal alignEment)

Background

Vertebral arthrodesis for degenerative pathology of the lumbar spine still remains burdened by clinical problems with significant negative results. The introduction of the sagittal balance assessment with the evaluation of the meaning of pelvic parameters and spinopelvic (PI-LL) mismatch offered new evaluation criteria for this widespread pathology, but there is a lack of consistent evidence on long-term outcome.

Methods

The authors performed an extensive systematic review of literature, with the aim to identify all potentially relevant studies about the role and usefulness of the restoration or the assessment of Sagittal balance in lumbar degenerative disease. They present the study protocol RELApSE (NCT05448092 ID) and discuss the rationale through a comprehensive literature review.

Results

From the 237 papers on this topic, a total of 176 articles were selected in this review. The analysis of these literature data shows sparse and variable evidence. There are no observations or guidelines about the value of lordosis restoration or PI-LL mismatch. Most of the works in the literature are retrospective, monocentric, based on small populations, and often address the topic evaluation partially.

Conclusions

The RELApSE study is based on the possibility of comparing a heterogeneous population by pathology and different surgical technical options on some homogeneous clinical and anatomic-radiological measures aiming to understanding the value that global lumbar and segmental lordosis, distribution of lordosis, pelvic tilt, and PI-LL mismatch may have on clinical outcome in lumbar degenerative pathology and on the occurrence of adjacent segment disease.

Posterior Pubic Incidence: A Novel Morphologic Spinopelvic Parameter Nearly Equal to Pelvic Incidence

BACKGROUND

Pelvic incidence (PI) and Jackson's angle are 2 major spinopelvic parameters that define the position of the sacrum within the pelvis. These parameters are measured on standing lateral radiography, and the identification of the hip axis is essential for measurements. Moreover, identifying the hip axis in patients with hip diseases or femoral head deformity is challenging. In this study, we described a novel parameter named posterior pubic incidence (PPI) that could be measured using the posterior pubic edge instead of the hip axis.

METHODS

Group A comprised 50 volunteers who underwent standing lateral lumbosacral radiography. Group B comprised 54 patients with abdominal or urologic problems who underwent supine computed tomography. The PI, pelvic tilt (PT), sacral slope, PPI, and posterior pubic tilt were measured. The differences between PI and PPI were evaluated. Linear regression analysis was used to predict the PI value from PPI.

RESULTS

The mean PI and PPI values were 47.41° ± 12.32° and 49.32° ± 11.94° in group A and 49.19° ± 9.99° and 49.99° ± 9.25° in group B, respectively. The mean absolute differences in groups A and B were 2.41° ± 1.63° and 1.9° ± 1.62°, respectively. High correlations were obtained between PI/PPI and pelvic tilt/posterior pubic tilt. PI could be calculated as PI° = PPI° - 2° on plain radiography and as PI° = PPI° - 1° on computed tomography.

CONCLUSIONS

PPI was strongly correlated with PI, which was nearly equal to PI, and may replace PI in formulas containing PI.

The effect of interlaminar Coflex stabilization in the topping-off procedure on local and global spinal sagittal alignment

PURPOSE

To investigate the effect of interlaminar Coflex stabilization (ICS) at various segments in the topping-off procedure on local and global spinal sagittal alignment.

METHODS

Eighty-nine consecutive patients with degenerative lumbar spinal stenosis (DLSS) who underwent ICS and transforaminal lumbar interbody fusion (TLIF) were retrospectively reviewed. They were divided into Group A (L4-L5 ICS + L5-S1 TLIF), Group B (L3-L4 ICS + L4-S1 TLIF), and Group C (L2-L3 ICS + L3-S1 TLIF) according to their fusion levels. The measured local sagittal parameters included the implanted segmental angle (ISA), intervertebral disc angle (IDA), intervertebral foreman height (IFH), and disc height. The assessed global sagittal parameters included thoracic kyphosis, lumbar lordosis (LL), the fused segment angle (FSA), the sacral slope, the pelvic tilt, pelvic incidence, and the sagittal vertical axis. The Oswestry Disability Index (ODI) and visual analog scales (VAS) were recorded to evaluate the clinical outcomes.

RESULTS

Regarding the local alignment parameters, the ISA and IDA decreased immediately after surgery in Groups A and B, followed by an increase at the last follow-up (all, P < 0.05). Conversely, the IFH of Groups A and B first increased after surgery and then decreased to approximately the original value (all, P < 0.05). No significant differences were evident between the local sagittal parameters at different time points in Group C. Regarding the global sagittal profiles, the LL and FSA exhibited a significant postoperative increase (both at P < 0.05) in all the groups. All three groups displayed significant improvements in the ODI, VAS-back pain, and VAS-leg pain. Furthermore, 4.5% (4/89) of the patients exhibited radiographic adjacent segment degeneration (ASD) at the last follow-up.

CONCLUSION

ICS during topping-off surgery led to a temporary loss of local lordosis, especially in the lower lumbar segment, while the intervertebral space realigned after middle-term follow-up. The topping-off procedure with ICS is a feasible and promising surgical option of DLSS since it reduces fusion levels and prevents ASD development.

Four types of global spine sagittal alignment and compensation mechanism in adult patients with lumbar degenerative disease

BACKGROUND

The objective of this study was to describe and classify common variations and compensation mechanisms in the sagittal alignment of the spine with lumbar degenerative disease.

METHODS

A total of 230 patients over 18 years old who underwent whole-spine X-rays to evaluate lower back pain were enrolled in this study. C7 slope, pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), cervical lordosis (CL), thoracolumbar kyphosis (TLK), and sagittal vertical axis (SVA) were measured. Patients were divided into Group A (balance without compensation), B (balance with compensation), C (unbalance with compensation), and D (unbalance without compensation) according to spinopelvic balance and thoracic compensation.

RESULTS

Group A had the largest LL, smallest PT, largest SS, and best clinical parameters of the four groups (p < 0.001, p < 0.001, p < 0.001, p < 0.001). The age increased gradually from Group B to Group D. Group B had an increased TK compared with Group A (p < 0.001). Group C had an increased TK compared with Group A (p < 0.001). Group D had an increased C7 slope compared with Group A (p = 0.022).

CONCLUSIONS

This classification is shown four different regional and global alignments of the spine. Compensation took place to keep the balance of the spine. Classification types were consistent with age, compensation abilities, and clinical parameters. This classification potentially represents a valuable tool for comprehensive analysis of lumbar degenerative before surgical treatment considering sagittal balance.

Surgical techniques in restoration lumbar lordosis: a biomechanical human cadaveric study

PURPOSE

Degenerative changes of the lumbar spine lead in general to decrease of lumbar lordosis (LL). This change affects the overall balance of the spine, and when surgery is deemed, necessary restoration of the LL is considered. How this restoration can be achieved is a matter of controversy. The main purpose of this cadaveric study was to investigate the different steps of common posterior surgical techniques to understand the contribution of each successive step in restoring LL.

METHODS

Ten fresh-frozen human lumbar spine specimens were used to perform a sequential correction and instrumentation with a pedicle screw construct.

RESULTS

The mean LL angle measured at L3-L4 in intact condition was 12.9°; after screw insertion and compression, this increased to 13.8° (+ 7%, p = 0.04), after bilateral facetectomy to 16.3° (+ 20%, p = 0.005), after discectomy and insertion of interbody cage to 18.0º (+ 9%, p = 0.012), after resection of the lamina and the processes spinosus to 19.8° (+ 10%, p = 0.017), and after resection of the anterior longitudinal ligament to 25.4° (+ 22%, p = 0.005).

CONCLUSIONS

Each step contributed statistically significant to restoration of segmental lordosis with bilateral facetectomy contributing the most in terms of percentage.

LEVEL OF EVIDENCE

IV.

Does Interbody Cage Lordosis and Position Affect Radiographic Outcomes After Single-level Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The objective of this study was to determine if the degree of interbody cage lordosis and cage positioning are associated with changes in postoperative sagittal alignment after single-level transforaminal lumbar interbody fusion (TLIF).

SUMMARY OF BACKGROUND DATA

Ideal sagittal alignment and lumbopelvic alignment have been shown to correlate with postoperative clinical outcomes. TLIF is one technique that may improve these parameters, but whether the amount of cage lordosis improves either segmental or lumbar lordosis (LL) is unknown.

METHODS

A retrospective review was performed on patients who underwent single-level TLIF with either a 5-degree or a 12-degree lordotic cage. LL, segmental lordosis (SL), disk height, center point ratio, cage position, and cage subsidence were evaluated. Correlation between center point ratio and change in lordosis was assessed using the Spearman correlation coefficient. Secondary analysis included multiple linear regression to determine independent predictors of change in SL.

RESULTS

A total of 126 patients were included in the final analysis, with 51 patients receiving a 5-degree cage and 75 patients receiving a 12-degree cage. There were no differences in the postoperative minus preoperative LL (∆LL) (12-degree cage: -1.66 degrees vs. 5-degree cage: -2.88 degrees, P =0.528) or ∆SL (12-degree cage: -0.79 degrees vs. 5-degree cage: -1.68 degrees, P =0.513) at 1-month follow-up. Furthermore, no differences were found in ∆LL (12-degree cage: 2.40 degrees vs. 5-degree cage: 1.00 degrees, P =0.497) or ∆SL (12-degree cage: 1.24 degrees vs. 5-degree cage: 0.35 degrees, P =0.541) at final follow-up. Regression analysis failed to show demographic factors, cage positioning, or cage lordosis to be independent predictors of change in SL. No difference in subsidence was found between groups (12-degree cage: 25.5% vs. 5-degree cage: 32%, P =0.431).

CONCLUSION

Lordotic cage angle and cage positioning were not associated with perioperative changes in LL, SL, or cage subsidence after single-level TLIF.

LEVEL OF EVIDENCE

Level III.

[Lumbar spinal stenosis]

Lumbar spinal stenosis (LSS) represents a frequent degenerative condition, however, striking a clear correlation between typical symptoms and imaging features remains a challenge. Reasons are a high prevalence of radiological LSS in the older population, a considerable percentage of asymptomatic LSS and the existence of differential diagnoses with similar symptomatology. This discrepancy also affects the outcomes - especially of surgically treated patients with LSS. When considering surgical decompression of LSS, the decision with regards to additive instrumentation and/or fusion remains a controversial point of discussion, in particular at the presence of degenerative spondylolisthesis. Recent, well-designed studies, however, clearly point towards a non-inferiority of decompression alone as opposed to the more invasive strategies.

The Standing and Sitting Spino-Pelvic Sagittal Alignment in Patients with Instrumented Lumbar Fusion Might Correlate with Adjacent Segment Degeneration

OBJECTIVES

Sitting is a common weight-bearing posture, like standing, but there still lacks enough understanding of sagittal alignment in sitting position for patients after lumbar fusion. This study aimed to investigate the accommodation of fixed spine from standing to sitting position and its influence on unfused segments.

METHODS

Sixty-two patients after lumbar fusion (test group) and 40 healthy volunteers (control group) were recruited in this research. All subjects underwent lateral radiographs of entire spine in the standing and sitting positions. The spinopelvic parameters including sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), and pelvic tilt (PT) were measured. The changes in parameters of patients between two positions were compared with control group, and patients were divided in different groups based on fusion level and their parameters were compared.

RESULTS

When changing from standing to sitting positions, a forward-moving SVA and TPA were observed in both patients and control groups, accompanied by the decrease in LL, TK and increase in PT, but the changes of patients were smaller in TPA, LL, and TK (6.5° ± 7.2° vs 9.7° ± 6.0°, 7.7° ± 8.3° vs 13.6° ± 8.5°, 2.2° ± 6.5° vs 5.4° ± 5.1°, respectively, p < 0.05). Increase of PT in the lumbosacral fixation group was lower than that in the control group (4.4° ± 9.1° vs 8.3° ± 7.1°, p < 0.05). Patients who had adjacent segments degeneration (ASD) showed more kyphosis in unfused lumbar segments than the other patients (16.4° ± 10.7° vs -1.0° ± 4.8°, p < 0.05) from standing to sitting.

CONCLUSIONS

The spine straightens in lumbar and thoracic curve, combined with forward-moving axis and pelvic retroversion when changing to the sitting position. However, these changes are relatively limited in patients after lumbar fusion, so the adjacent unfused lumbar segments compensate to stress during sitting and this may be related to ASD.

Pelvic incidence measurement with supine magnetic resonance imaging: A validity and reliability study

OBJECTIVE

Classically, pelvic incidence (PI) and other spinopelvic sagittal parameters are measured using plain x-ray obtained with the patient standing. However, it is difficult to obtain a perfect mid-sagittal appearance of the sacral endplate and superimposition of both femoral heads from a plain x-ray. Overlapping of the iliac wings also could obscure the appearance of the sacral endplate. Recent studies showed that MRI was more reliable than x-ray for evaluating some spinal sagittal parameters. To our knowledge, measurements of spinopelvic sagittal parameters using supine MRI have not been reported previously. We assessed the validity and reliability of measurements of spinopelvic sagittal parameters from standing lateral x-rays and supine magnetic resonance imaging (MRI).

METHODS

We recruited 26 asymptomatic volunteers for this study. Standing lateral lumbosacral radiographs, including femoral heads and spinopelvic MRI images with coronal images of the femoral heads were performed. The anatomic reference point required to measure PI was found on coronal MRI images and transferred to the midline sagittal MRI using the bladder wall as a second reference point. PI, sacral slope (SS), and pelvic tilt (PT) were measured on x-ray and MRI images. Validity and reliability of results also were tested.

RESULTS

Of 14 males and 12 females (average age, 31.30), PI was obtained from x-ray and MRI in 52. ± 6.89 and 51.42 ± 6.43, respectively. From standing x-ray to supine MRI, PT decreased by 3.16°, while SS increased 2.5°. A paired t-test showed a significant difference between PT values from x-ray and MRI. The correlation was highest between the x-ray and MRI measurements of PI, PT, and SS, respectively. Intraobserver and interobserver reliabilities were between 0.88 and 0.96 on x-ray and MRI. All reliabilities were excellent, although MRI values were higher.

CONCLUSION

MRI was more reliable in the measurement of spinopelvic parameters than classic standing x-ray examination. Higher reliability and being radiation-free could make MRI a good alternative to standing x-ray.

Sagittal Balance Using Position and Orientation of Each Vertebra in an Asymptomatic Population

STUDY DESIGN

A monocentric, retrospective radiographic study with 99 asymptomatic volunteers.

OBJECTIVE

The authors performed the postural analysis commonly scheduled when evaluating sagittal balance in a vertebra-by-vertebra manner by enrolling an asymptomatic population. They measured the position and angulation of each vertebra to reveal those for which the spatial positioning could be relevant during spinal surgeries.

SUMMARY OF BACKGROUND DATA

Several recent publications detailed the sagittal alignment parameters and focus on global analysis parameters. Some patients with identical commonly evaluated spinal parameters have exhibited very different profiles, with notable differences in vertebral positions and orientations. Therefore, a fine segmental analysis of position of each vertebra could be interest to gain understanding of spine alignment.

MATERIALS AND METHODS

The authors obtained full-spine EOS x-rays of 99 volunteers in the standard free-standing position. We used a validated three-dimensional reconstruction technique to extract current spinal parameters and the positions and angulations of all vertebrae and lumbar discs. Particular attention was paid to the positions and angulations of the apical and transitional vertebrae in the general population and in subgroups according to pelvic incidence (PI).

RESULTS

T1 was the most common transitional cervicothoracic vertebra (in 89.9% of subjects) and was oriented downwards by an average of 22.0° (SD=7.3°, minimum=2.3°, maximum=40.1°). The thoracic apex trio of T5 (22.2%), T6 (28.3%), and T7 (36.4%) were equally found. The transitional thoracolumbar vertebrae were L1 (39.4%) and T12 (33.3%). The lumbar apex was usually the L3-L4 disc (36.4%). T1 seemed to be the transitional vertebra (90%) irrespective of the PI. For the other relevant vertebrae, the greater the PI, the more cranial the vertebra.

CONCLUSIONS

We performed a detailed three-dimensional assessment of overall spinal balance using positional and rotational parameters. The positions and orientations of all vertebrae were specified, particularly the apical and transitional vertebrae.

LEVEL OF EVIDENCE

Level 3.

Upper versus Lower Lumbar Lordosis Corrections in Relation to Pelvic Tilt - An Essential Element in Surgical Planning for Sagittal Plane Deformity

STUDY DESIGN

Retrospective study of a multicenter Adult Spinal Deformity (ASD) Database.

OBJECTIVE

To investigate the change in Pelvic tilt (PT) imparted by regional changes in lumbar lordosis at 2-year minimum follow up.

SUMMARY OF BACKGROUND DATA

The distribution of lumbar lordosis between L1-4 and L4-S1 is known to vary based on pelvic incidence (PI). However, the extent to which regional changes effect PT is not clearly elucidated. This information can be useful for ASD surgical planning.

METHODS

Operative patients from a multicenter ASD database were included with Lowest Instrumented Vertebrae (LIV) S1/Ilium, >5 levels of fusion, Proximal Junction Kyphosis (PJK) angle < 20, and >5 degrees of change in lumbar lordosis from L4-S1 and L1-4. Radiographic analysis was performed evaluating Thoracic Kyphosis (TK), T10-L2 kyphosis (TL), L1-S1 lordosis (LL), L4-S1 lordosis, L1-4 lordosis, sagittal vertical axis (SVA) and PI-LL from preoperative to postoperative, and change at 2-years follow-up. Stepwise regression analysis was performed in order to determine the relationship between PT and the above radiographic parameters. Health-related quality of life (HRQOL) outcomes were also compared between preoperative and postoperative timepoints at 2 years.

RESULTS

103 patients met inclusion for the study. There was improvement in all the radiographic parameters and HRQOLs at 2 years follow-up (p < 0.01). Stepwise regression model showed an inverse relationship between PT and LL change (r = 0.71, p < 0.01). Regionally, an increase in 10 degrees from L4-S1 correlated with a 2.4 degree decrease in PT (p < 0.01), while an increase in 10 degrees from L1-4 resulted in a 1.6 degree decrease in PT (p < 0.01).

CONCLUSION

In the surgical planning for ASD, our data demonstrated significant correlational difference between corrections in the upper (L1-4) and lower (L4-S1) lumbar spine and PT changes. These calculations can be useful in planning sagittal plane corrections for ASD.

The incidence of failed back surgery syndrome varies between clinical setting and procedure type

BACKGROUND

Failed back surgery syndrome (FBSS) is a significant cause of lumbar disability and is associated with severe patient morbidity. As the etiology of FBSS is not completely elucidated, the risk factors and evaluation of patients with FBSS remains challenging. Our analysis of a wide variety of operation types, clinical setting, and their correlation to FBSS seeks to allow fellow clinicians to be aware of the potential risk factors that leads to this devastating diagnosis.

METHODS

Data were obtained for patients undergoing anterior lumbar fusion, posterior lumbar fusion, or decompression procedures from January 2010 to December 2017 from the Mariner insurance database. Rates of FBSS at six- and twelve-months post-surgery were determined for patients undergoing single/multilevel procedures according to place of service, and approach/procedure type.

RESULTS

From 2010 to 2017, 102,047 patients underwent lumbar fusion or decompression surgery (54% decompression procedures, 36% posterior fusions, and 8.9% anterior fusions).5.4% of patients were diagnosed with FBSS within six months of the index procedure, and 8.4% were diagnosed with FBSS within twelve months. FBSS was higher in the inpatient (6.0%) vs. outpatient (4.3%) cohort. Among the surgical techniques, multi-level procedures had significantly higher rates of FBSS than single-level procedures, the highest being 10% in multi-level inpatient decompression procedures (p < 0.05).

CONCLUSION

The highest rates of FBSS occurred in in the elderly (age group 70-74), for those patients whose index procedure was received in an inpatient setting, as well as for those receiving a multi-level surgery.

Long-term Radiological and Clinical Outcome after Lumbar Spinal Fusion Surgery in Patients with Degenerative Spondylolisthesis: A Prospective 6-Year Follow-up Study

Objective

To assess which radiological alignment parameters are associated with a satisfactory long‐term clinical outcome after performing lumbar spinal fusion for treating degenerative spondylolisthesis.

Methods

This single‐center prospective study assessed the relation between radiological alignment parameters measured on standing lateral lumbar spine radiographs and the patient‐reported outcome using four different questionnaires (COMI, EQ‐5D, ODI and VAS) as primary outcome measures (level of evidence: II). The following spinopelvic alignment parameters were used: gliding angle, sacral inclination, anterior displacement, sagittal rotation, lumbar lordosis, sacral slope, pelvic tilt and pelvic incidence. Furthermore, the length of stay and perioperative complications were documented. Only cases from 2013 to 2015 of low‐grade degenerative lumbar spondylolisthesis (Meyerding grades I and II) were considered. The patients underwent open posterior lumbar fusion surgery by pedicle screw instrumentation and cage insertion. The operative technique was either a posterior lumbar interbody fusion (PLIF) or a transforaminal lumbar interbody fusion (TLIF) performed by three different senior orthopedic surgeons. Exclusion criteria were spine fractures, minimally invasive techniques, underlying malignant diseases or acute infections, previous or multisegmental spine surgery as well as preoperative neurologic impairment. Of 89 initially contacted patients, 17 patients were included for data analysis (11 males, six females).

Results

The data of 17 patients after mono‐ or bisegmental lumbar fusion surgery to treat low‐grade lumbar spondylolisthesis and with a follow‐up time of least 72 months were analyzed. The mean age was 66.7 ± 11.3 years. In terms of complications two dural tears and one intraoperative bleeding occurred. The average body mass index (BMI) was 27.6 ± 4.4 kg/m² and the average inpatient length of stay was 12.9 ± 3.8 days (range: 8–21). The long‐term clinical outcome correlated significantly with the change of the pelvic tilt (r_s = −0.515, P < 0.05) and the sagittal rotation (r_s = −0.545, P < 0.05). The sacral slope was significantly associated with the sacral inclination (r_s = 0.637, P < 0.01) and the pelvic incidence (r_s = 0.500, P < 0.05). In addition, the pelvic incidence showed a significant correlation with the pelvic tilt (r_s = 0.709, P < 0.01). The change of the different clinical scores over time also correlated significantly between the different questionnaires.

Conclusions

The surgical modification of the pelvic tilt and the sagittal rotation are the two radiological alignment parameters that can most accurately predict the long‐term clinical outcome after lumbar interbody fusion surgery.

Biomechanical role of cement augmentation in the vibration characteristics of the osteoporotic lumbar spine after lumbar interbody fusion

Under whole body vibration, how the cement augmentation affects the vibration characteristic of the osteoporotic fusion lumbar spine, complications, and fusion outcomes is unclear. A L1-L5 lumbar spine finite element model was developed to simulate a transforaminal lumbar interbody fusion (TLIF) model with bilateral pedicle screws at L4-L5 level, a polymethylmethacrylate (PMMA) cement-augmented TLIF model (TLIF-PMMA) and an osteoporotic TLIF model. A 40 N sinusoidal vertical load at 5 Hz and a 400 N preload were utilized to simulate a vertical vibration of the human body and the physiological compression caused by muscle contraction and the weight of human body. The results showed that PMMA cement augmentation may produce a stiffer pedicle screw/rod construct and decrease the risk of adjacent segment disease, subsidence, and rod failure under whole-body vibration(WBV). Cement augmentation might restore the disc height and segmental lordosis and decrease the risk of poor outcomes, but it might also increase the risk of cage failure and prolong the period of lumbar fusion under WBV. The findings may provide new insights for performing lumbar interbody fusion in patients affected by osteoporosis of the lumbar spine. Graphical abstract.

"Reverse roussouly": cervicothoracic curvature ratios define characteristic shapes in adult cervical deformity

PURPOSE

To investigate normal curvature ratios of the cervicothoracic spine and to establish radiographic thresholds for severe myelopathy and disability, within the context of shape.

METHODS

Adult cervical deformity (CD) patients undergoing cervical fusion were included. C2-C7 Cobb angle (CL) and thoracic kyphosis (TK), using T2-T12 Cobb angle, were used as a ratio, ranging from -1 to + 1. Pearson bivariate r and univariate analyses analyzed radiographic correlations and differences in myelopathy(mJOA > 14) or disability(NDI > 40) across ratio groups.

RESULTS

Sixty-three CD patients included. Regarding CL:TK ratio, 37 patients had a negative ratio and 26 patients had a positive ratio. A more positive CL:TK correlated with increased TS-CL(r = 0.655, p =  < 0.001)and mJOA(r = 0.530, p = 0.001), but did not correlate with cSVA/SVA or NDI scores. A positive CL:TK ratio was associated with moderate disability(NDI > 40)(OR: 7.97[1.22-52.1], p = 0.030). Regression controlling for CL:TK ratio revealed cSVA > 25 mm increased the odds of moderate to severe myelopathy and cSVA > 30 mm increased the odds of significant neck disability. Lastly, TS-CL > 29 degrees increased the odds of neck disability by 4.1 × with no cutoffs for severe mJOA(p > 0.05).

CONCLUSIONS

Cervical deformity patients with an increased CL:TK ratio had higher rates of moderate neck disability at baseline, while patients with a negative ratio had higher rates of moderate myelopathy clinically. Specific thresholds for cSVA and TS-CL predicted severe myelopathy or neck disability scores, regardless of baseline neck shape. A thorough evaluation of the cervical spine should include exploration of relationships with the thoracic spine and may better allow spine surgeons to characterize shapes and curves in cervical deformity patients.

Clinical outcome after lumbar spinal fusion surgery in degenerative spondylolisthesis: a 3-year follow-up

INTRODUCTION

Lumbar spinal fusion surgery is a widely accepted surgical treatment in degenerative causes of lumbar spondylolisthesis. The benefit of reduction of anterior displacement and restoration of sagittal parameters is still controversially debated. Purpose of the underlying publication was to analyze the influence of radiographic sagittal parameters of the spine in aspects of changes in postoperative clinical outcome.

MATERIALS AND METHODS

By prospective analysis, we included patients with low-grade degenerative lumbar spondylolisthesis (Meyerding grades I and II) with mono- or bisegmental fusion surgery with a minimum follow-up data of 3 years. For clinical outcome measures, COMI, ODI and EQ-5D were used. Spinopelvic parameters (sacral inclination, pelvic tilt, sacral slope and pelvic incidence, lumbar lordosis and lumbar index as well as anterior displacement and sagittal rotation) were measured on plain radiographs.

RESULTS

We could observe a significant benefit in clinical outcome after lumbar fusion surgery in low-grade spondylolisthesis in our mid-term follow-up data including 32 patients. By surgical reduction, we could see significant restoration of anterior displacement and sagittal rotation. Interestingly, a significant correlation between restoration of both sagittal rotation and sacral inclination and clinical outcome score was observed in the 3-year follow-up.

CONCLUSION

In low-grade spondylolisthesis, spinal fusion surgery is a well-established surgical procedure; however, the impact of sagittal parameters and reduction of anterior displacement remains controversial. Within our findings, restoration of sagittal parameters showed significant correlation to improvement in clinical outcome in our mid-term follow-up data.

The Association Between Sagittal Spinopelvic Alignment and Persistent Low Back Pain After Posterior Lumbar Interbody Fusion for Treatment of Mild L5-S1 Spondylolisthesis: A Retrospective Study

Introduction

The aim of this study was to explore the association between sagittal spinopelvic alignment and persistent low back pain (PLBP) following posterior decompression and instrumented fusion for mild L5-S1 spondylolisthesis.

Methods

By retrieving medical records from January 2015 to April 2020, 200 patients following PLIF for mild L5-S1 spondylolisthesis were retrospectively reviewed. Patients were divided into two groups: PLBP group and non-PLBP group. The baseline characteristics and radiographic parameters were analyzed and compared between groups.

Results

The PLBP group comprised 26 patients, and the non-PLBP group comprised 174 patients. No significant differences in preoperative spinopelvic parameters were found between the two groups (p > 0.05). There were statistically significant differences between the preoperative and postoperative variations of LL, SL, LSA, SD, and HOD spinopelvic parameters, regardless of group (p < 0.05). Postoperative PT and SS differed significantly between the PLBP group and non-PLBP group (p < 0.05). In the PLBP group, there were no significant differences between preoperative and postoperative PT; the same applied to SS. However, significant differences were found for the variations in preoperative and postoperative PT and SS between the two groups. The ΔPT was found as an independent risk factor for postoperative PLBP.

Conclusion

Patients with mild L5-S1 spondylolisthesis with PLBP after posterior lumbar spinal fusion had decreased SS and increased PT.

Emerging Issues Questioning the Current Treatment Strategies for Lumbar Disc Herniation

Lumbar disc herniation is among the common phenotypes of degenerative lumbar spine diseases, significantly affecting patients' quality of life. The practice pattern is diverse. Choosing conservative measures or surgical treatments is still controversial in some areas. For those who have failed conservative treatment, surgery with or without instrumentation is recommended, causing significant expenditures and frustrating complications, that should not be ignored. In the article, we performed a literature review and summarized the evidence by subheadings to unravel the cons of surgical intervention for lumbar disc herniation. There are tetrad critical issues about surgical treatment of lumbar disc herniation, i.e., favorable natural history, insufficient evidence in a recommendation of fusion surgery for patients, metallosis, and implant removal. Firstly, accumulating evidence reveals immune privilege and auto-immunity hallmarks of human lumbar discs within the closed niche. Progenitor cells within human discs further expand the capacity with the endogenous repair. Clinical watchful follow-up studies with repeated diagnostic imaging reveal spontaneous resolution for lumbar disc herniation, even calcified tissues. Secondly, emerging evidence indicates long-term complications of lumbar fusion, such as adjacent segment disease, pseudarthrosis, implant failure, and sagittal spinal imbalance, which get increasing attention. Thirdly, systemic and local reactions (metallosis) for metal instrumentation have been noted with long-term health concerns and toxicity. Fourthly, the indications and timing for spinal implant removal have not reached a consensus. Other challenging issues include postoperative lumbar stiffness. The review provided evidence from a negative perspective for surgeons and patients who attempt to choose surgical treatment. Collectively, the emerging underlying evidence questions the benefits of traditional surgery for patients with lumbar disc herniation. Therefore, the long-term effects of surgery should be closely observed. Surgical decisions should be made prudently for each patient.

Transforaminal lumbar interbody fusion with a silicon nitride cage demonstrates early radiographic fusion

BACKGROUND

Degeneration of the lumbar spine is common in aging adults and reflects a significant morbidity burden in this population. In selected patients that prove unresponsive to non-surgical treatment, posterior lumbar fusion (PLF) surgery, with or without adjunctive transforaminal lumbar interbody fusion (TLIF) can relieve pain and improve function. We describe here the radiographic fusion rates for PLF versus TLIF, using an intervertebral spinal cage made of silicon nitride ceramic (chemical formula Si₃N₄).

METHODS

This retrospective cohort analysis enrolled 99 patients from August 2013 to January 2017; 17 had undergone PLF at 24 levels, while 82 had undergone TLIF at 104 levels. All operations were performed by a single surgeon at one institution. Radiographic and clinical outcomes were compared between PLF and TLIF at 2 and 6 weeks and then at 3, 6, 12, and 24 months.

RESULTS

TLIF patients fused at higher rates compared to PLF at the 3-month (38.5% vs. 8.3%, P=0.006), 6-month (78.7% vs. 35.0%, P<0.001) and 12-month time periods (97.9% vs. 81.3%, P=0.018), with no difference at 24 months (100% vs. 94.4%, P=0.102). Index level segmental motion was significantly less and intervertebral disc height was improved in TLIF over PLF at all follow up intervals. Foraminal height was only greater in early follow up periods (2 weeks, 6 weeks and 3 months). TLIF patients experienced lover rates of PI-LL mismatch which was maintained across long term follow-up. Pelvic tilt was lower following TLIF compared to PLF, with no differences in complication rates between study groups.

CONCLUSIONS

Our retrospective series demonstrated that TLIF performed with silicon nitride interbody cages led to earlier radiographic fusion, greater restoration of disc and foraminal height, increased segmental rigidity and improved sagittal alignment when compared to PLF alone.

Analysis of measurement changes in pelvic incidence according to pelvic rotation using a three-dimensional model

Background

Pelvic incidence (PI) is used as a key parameter in surgical correction of adult spinal deformity (ASD). However, reflecting the exact center or inclination of the three-dimensional anatomical structures on the two-dimensional (2D) sagittal radiographs is limited, resulting in measurement errors. Therefore, we evaluated whether there is a change in PI measurement according to the actual rotation of the pelvis, and conducted a study on a more accurate method for PI measurement using 2D sagittal radiographs.

Methods

From 2014 to 2015, the data of 30 patients who visited our outpatient clinic were analyzed retrospectively. CT scans including those of the lower lumbar spine, pelvis, and both femurs in the DICOM format were imported to Mimics Research 17.0 (Materialise NV, Belgium), SolidWorks (Dassault systems, France), and AutoCAD 2014 (AUTODESK, US). The changes in PI according to vertical and horizontal pelvic rotations were evaluated.

Results

The average PIs according to the horizontal pelvic rotations measured on AutoCAD with 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, and 40° were 48.8°, 48.7°, 48.3°, 47.8°, 46.9°, 45.6°, 44.0°, 42.2°, and 39.9°, respectively. The PI with an acceptable error of 6° on radiographs was 35° in the horizontal pelvic rotation. The average PIs according to the vertical pelvic rotations measured on AutoCAD with 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, and 40° were 48.8°, 49.0°, 49.5°, 50.2°, 51.3°, 52.7°, 54.4°, 56.6°, and 59.4°, respectively. The PI with an acceptable error of 6° on radiographs was 30° in the vertical pelvic rotation.

Conclusions

This study revealed that the PI value could differ from the actual anatomical value due to the horizontal and vertical rotation of the pelvis while acquiring the radiograph. Regarding whole-spine lateral radiographs, errors in PI measurement may occur due to pelvic rotation or nonvertical projection of X-rays. In the standing pelvic lateral radiographs, ensuring superposition of the femoral heads at the center and obtaining the straight sacral endplate by referring to CT or magnetic resonance imaging would be a more accurate measurement method to define PI.

Correlation of spinopelvic parameters with functional outcomes in surgically managed cases of lumbar spinal tuberculosis- A retrospective study

BACKGROUND

The advanced stage of vertebral involvement in spinal tuberculosis (STB) can cause vertebral body collapse, which leads to kyphotic deformity and paraplegia in severe cases. Surgery is indicated in patients having disabling back pain, progressive neurological deficit, and instability in spine despite conservative management. The derangement of lumbar parameters, especially the loss of lumbar lordosis has been found to cause functional deterioration in patients. With the current evidences in place, this study was done to evaluate the correlation between the restoration of lumbar lordosis, pelvic parameters, and functional outcome when posterior only approach was used to manage the lumbar STB.

METHODS

Active Tuberculosis of lumbar vertebra (L1-S1) confirmed by radiology (X-ray, MRI) and histopathological examination were included. All the cases scheduled for surgery underwent radiographs, CT scan, and MRI scans. Lumbar lordosis and other pelvic parameters were calculated on X-rays. VAS scores and ODI scores were documented during the follow-up to assess functional well-being.

RESULTS

A total of 33 (22 M:11 F) patients were included in the study. The mean lumbar lordosis pre-operatively was -22.84 ± 11.19° which was corrected to -37.03 ± 9.02° (p < 0.05) post-operatively. The pelvic tilt pre-operatively was 25.33 ± 6.75° which was corrected to 19.63 ± 5.84° (p < 0.05) post-operatively. The mean ODI improved from 84.33 ± 11.84 to 26.93 ± 8.74 (p < 0.05) at the final follow-up. The mean VAS score pre-operatively was 8.06 ± 1.27 which improved to 2.45 ± 0.93 (p < 0.05) in the post-operative period.

CONCLUSION

The study found a strong negative correlation between ODI scores and lumbar lordosis and a strong positive correlation between pelvic tilt and ODI scores. But the correlation needs to be further studied and evaluated by a well-constructed study especially with a control group treated conservatively.

SPINOPELVIC PARAMETERS AFTER POSTERIOR LUMBAR ARTHRODESIS IN DEGENERATIVE SPINAL DISEASES

ABSTRACT Introduction: Spinopelvic parameters related to sagittal balance have become increasinglyimportantamong spine surgeons due to their correlation with patient satisfaction rates. Objective: The goal of this study was to evaluate changes in spinal sagittal balance after lumbar spine surgery using PLIF, the posterior lumbar interbody fusion technique. Methods: The sample consisted of adult patients with degenerative spinal disease submitted to posterior lumbar arthrodesis. Patients between 18 and 70 years of agewho underwent surgeryfrom 2015 to 2017 were included in the study and divided into short (1 level) and long arthrodesis (2 to 4 levels) groups. Radiographic analysis of the spinopelvic parameters, measured before and after lumbar arthrodesis, was conducted using the SURGIMAP software. Then we evaluated the variation between pre- and postoperative measurements and performed correlation and linear regression analyses between the parameters. Results: The sample was composed of 80 patients (48 men). The mean age was lower in the short arthrodesis group than in the long arthrodesis group (52.67 ± 9.66 years versus 59.37 ± 9.30 years, respectively; p<0.0025). Significant variations in lumbar lordosis, pelvic tilt, sagittal vertical axis, T1 pelvic angle, and pelvic incidence minus lumbar lordosis were found in both short and long arthrodesis groups. The variation was significantly larger in the long than in the short arthrodesis group. Conclusion: In adult degenerative spine disease, short and long arthrodesis of the lumbar spine by PLIF allows correction of the spinopelvic parameters. Level of evidence III; Retrospective, comparative study.

Caudad Insertion of Pedicle Screws Facilitates Interbody Distraction During Spondylolisthetic Vertebrae Restoration: A Retrospective Study

INTRODUCTION

Based on the results of long-term clinical and radiological follow-up studies of decompression and fusion with internal fixation for degenerative lumbar spondylolisthesis (DLS), we recognized that the direction of the pedicle screw affects the stability of the fixation. However, few studies have analyzed the role of pedicle screw insertion trajectory in disc height recovery after fusion. We therefore analyzed patients' general information, clinical efficacy and sagittal, coronal and implant parameters to determine whether there is a correlation between the insertion trajectory of screws and the recovery of intervertebral space height, with the ultimate aim to provide a basis for improving the clinical efficacy and radiological outcomes of patients with DLS and to identify an optimal technique for spine surgeons that would benefit patients with spondylolisthesis.

METHODS

From May 2015 to October 2019, patients who underwent single-segment decompression and fusion with internal fixation for DLS at our department were screened for enrollment in the study. The clinical history, pre- and post-operative lumbar sagittal parameters, intervertebral height, rate of recovery from spondylolisthesis and pedicle screw angle of inpatients were recorded and followed up for at least 6 months. Clinical assessments included the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS) for lower back and leg pain. Data on screw angle, fusion segment intervertebral space height and clinical outcome were the primary outputs. Pearson correlation and multivariate regression analyses were performed to investigate the relationship between the pedicle screw angle, the sagittal parameters of the fusion segment and clinical efficacy.

RESULTS

A total of 50 patients were initially enrolled, two patients were lost to follow-up after 6 months, 48 patients (17 men, 31 women) were eventually enrolled, and the follow-up rate was 96%. At least 6 months after the operation, vertebral spondylolisthesis improved to varying degrees [> 80% in 17 cases (35.4%) and > 20% in 43 cases (87.5%), respectively]. Changes in disc height (DH) were significantly associated with lower pedicle screw angle, while lumbar lordosis and segment lordosis remained the same. Multivariate regression analysis showed a significant negative correlation between the upper and lower pedicle screw angles and the change in DH (P < 0.05). At 2 weeks post-operation, the VAS score for low back pain and the ODI had improved significantly compared to pre-operation (P < 0.05).

CONCLUSIONS

These results suggest that the Caudad insertion trajectory technique of pedicle screws may be an ideal alternative for the treatment of DLS.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR): ChiCTR1800020368.

Sagittal balance: from theory to clinical practice

Adequate sagittal balance (SB) is essential to maintain an upright, efficient, and painless posture. It has been shown that sagittal profile alterations affect quality of life of patients with a similar or even greater impact than chronic disease.

Evaluation of the SB has gained much relevance in recent years, with recognition of its importance in the evaluation of spinal pathology.

This review summarizes the basic principles of SB, aiming to obtain a practical, simple and understandable evaluation of the sagittal profile of a patient.

SB is a dynamic process that involves a varying degree of energy expenditure. Distinguishing between a balanced, compensated imbalance or decompensated imbalanced patient, is relevant to diagnosis and therapeutic decision-making.

Cite this article: EFORT Open Rev 2021;6:1193-1202. DOI: 10.1302/2058-5241.6.210062

Optimal Lumbar Lordosis Correction for Adult Spinal Deformity with Severe Sagittal Imbalance in Patients Over Age 60: Role of Pelvic Tilt and Pelvic Tilt Ratio

STUDY DESIGN

A retrospective study.

OBJECTIVES

The purpose of this study was to evaluate optimal and ideal target values of the spine balance correction in elderly patients with adult spinal deformity who were over the age of 60 years.

SUMMARY OF BACKGROUND DATA

The target values of the Scoliosis Research Society -Schwab classification to obtain satisfactory alignment and favorable outcomes are used in many spinal reconstruction surgeries. However, uniformly applying the Scoliosis Research Society-Schwab classification to all elderly patients aged 60 years or older showing sagittal malalignment may lead to several inconsistencies.

METHODS

This study included 121 patients (average age 70.5 yr and a minimum 2-yr follow-up) with adult spinal deformity who underwent long-segment fusion from T10 to sacrum. We used Pearson's correlation coefficient to analyze the relationship between clinical and radiographic parameters, and multilinear regression analysis and multivariate logistic regression model (backward elimination method) were conducted using the correlation factors of postoperative (Post) and last follow-up (Last) sagittal vertical axis to find the risk factors of Post sagittal imbalance.

RESULTS

Logistic regression analysis with the correlation factors of Post and Last sagittal vertical axis led to risk factors of Post sagittal imbalance, and after confirming the significance of each path, it was confirmed that the effects of pelvic incidence (PI)- lumbar lordosis (LL) and Post pelvic tilt ratio (PTr) were valid (P < 0.05). After using ROC curve, target value of PI-LL was 1.33, and that of PTr was 25.95%.

CONCLUSION

Through our study, the risk factors of Post sagittal imbalance were the Post value of PI-LL and that of PTr, and target value of PI-LL was <1.33 and that of PTr was <25.95%. These target values can be effective guidelines for spine surgeons who perform spine reconstruction surgeries for elderly patients with a pure sagittal imbalance based on Schwab's formula.Level of Evidence: 4.

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

BACKGROUND

Expandable transforaminal lumbar interbody fusion (TLIF) cages capable of multidirectional in situ expansion have gained popularity as they increase axial surface area for fusion and may enhance lordotic correction through a traditional MIS surgical corridor.

OBJECTIVE

To evaluate and compare the radiographic and clinical outcomes between a novel expandable vs. static MIS TLIF cage for the treatment of degenerative disc disease.

STUDY DESIGN

A single center retrospective review of 120 consecutive adult patients undergoing 1 or 2-level MIS TLIF with an expandable (n=60) or static cage was performed between 2015-2019. Preoperative and 1-year postoperative radiographic and clinical outcomes were assessed by upright flexion/extension radiographs and serial confidential surveys.

RESULTS

120 patients (mean age 63.5 years, 60.0 % female) undergoing 1 and 2-level MIS TLIF met inclusion criteria. A statistically significant reduction of spondylolisthesis, restoration of foraminal, anterior and posterior disc height was achieved in both cohorts, but greater in the ECC (all p<0.05). Comparable rates of fusion, 93% and 91% were observed in the ECC and SCC. A significant reduction in NRS back and ODI scores were observed in both cohorts but more pronounced in the ECC (5.9±2.4 to 2.2±1.9 and 37.3±16.2 to 17.1±15.2) vs. SCC (6.2±2.8 to 3.2±2.5 and 41.8±16.1 to 24.3±17.5) (p<0.05). One instance of cage migration requiring reoperation occurred in the ECC.

CONCLUSIONS

Taken together, these radiographic and clinical findings suggest an expandable cage placed through an MIS corridor represents a safe, equitable and efficacious alternative to a static TLIF in adults with degenerative lumbar pathology.

Does Cervical Alignment Matter? The Effect of 2-level Anterior Cervical Discectomy and Fusion on Sagittal Alignment and Patient-reported Outcomes

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

This study aimed to determine the change in cervical sagittal balance following 2-level anterior cervical discectomy and fusion (ACDF) and whether the degree of change was associated with improvement in patient-reported outcomes (PROs).

SUMMARY OF BACKGROUND DATA

Sagittal balance in cervical spine surgery has been recognized as an important surgical goal. However, its influence on clinical outcomes following anterior decompressive procedures remains debatable.

MATERIALS AND METHODS

Patients who underwent primary 2-level ACDF for cervical spondylotic radiculopathy and/or myelopathy were identified from an institutional spine registry. Radiographic measurements were done preoperatively, postoperatively, and at minimum 24 months follow-up. Measurements comprised segmental lordosis (SL), C2-C7 cervical lordosis (CL), C2-C7 sagittal vertical axis, C7 slope (C7S), T1 slope (T1S) and C7 slope minus cervical lordosis (C7S-CL). Disk heights were measured preoperatively and postoperatively. PROs including the Neck Disability Index, Short Form-36, and Visual Analog Scale for neck pain and arm pain were collected preoperatively and at 24 months postoperatively.

RESULTS

In total, 90 patients were included. Mean follow-up was 58.6±22.9 months. Significant improvement in all PROs was achieved at 24 months (P<0.05). SL was -1.2±8.2 degrees preoperatively, increased to 5.2±5.9 degrees postoperatively (P<0.001), and decreased to 1.2±6.2 degrees at follow-up (P=0.005). CL was 8.5±12.5 degrees preoperatively, increased to 10.8±12.4 degrees postoperatively (P=0.018), and maintained at 10.9±11.2 degrees at follow-up (P=0.030). Sagittal vertical axis, C7S, T1S, and C7S-CL did not change significantly. Significant increases in disk heights were achieved postoperatively (P<0.001). Fusion rate was 98.9% at follow-up. PROs were not related to radiologic measurements. Maintaining or increasing CL or SL was not related to a greater degree of improvement in PROs.

CONCLUSIONS

Two-level ACDF restored segmental and global CL, but changes in cervical sagittal alignment did not correlate with the magnitude of improvement in PROs. Adequate decompression with solid fusion remains fundamental to achieving good clinical outcomes in patients with degenerative cervical disease.