Effect of segmental lordosis on the clinical outcomes of 2-level posterior lumbar interbody fusion for 2-level degenerative lumbar spondylolisthesis

Clinical effectiveness of reduction and fusion versus in situ fusion in the management of degenerative lumbar spondylolisthesis: a systematic review and meta-analysis

PURPOSE

To compare the clinical effectiveness of reduction and fusion with in situ fusion in the management of patients with degenerative lumbar spondylolisthesis (DLS).

METHODS

The systematic review was conducted following the PRISMA guidelines. Relevant studies were identified from PubMed, Embase, Scopus, Cochrane Library, ClinicalTrials.gov, and Google Scholar. The inclusion criteria were: (1) comparative studies of reduction and fusion versus in situ fusion for DLS patients, (2) outcomes reported as VAS/NRS, ODI, JOA score, operating time, blood loss, complication rate, fusion rate, or reoperation rate, (3) randomized controlled trials and observational studies published in English from the inception of the databases to January 2023. The exclusion criteria included: (1) reviews, case series, case reports, letters, and conference reports, (2) in vitro biomechanical studies and computational modeling studies, (3) no report on study outcomes. The risk of bias 2 (RoB2) tool and the Newcastle-Ottawa scale was conducted to assess the risk of bias of RCTs and observational studies, respectively.

RESULTS

Five studies with a total of 704 patients were included (375 reduction and fusion, 329 in situ fusion). Operating time was significantly longer in the reduction and fusion group compared to in situ fusion group (weighted mean difference 7.20; 95% confidence interval 0.19, 14.21; P = 0.04). No additional significant intergroup differences were noted in terms of other outcomes analyzed.

CONCLUSION

While the reduction and fusion group demonstrated a statistically longer operating time compared to the in situ fusion group, the clinical significance of this difference was minimal. The findings suggest no substantial superiority of lumbar fusion with reduction over without reduction for the management of DLS.

Radiographic predictors of reaching minimal clinically important difference following lumbar fusion surgery in patients with degenerative lumbar spondylolisthesis

PURPOSE

The present study aimed to (1) compare sagittal alignment between patients with degenerative lumbar spondylolisthesis (DLS) who reached or missed the minimal clinically important difference (MCID) for clinical outcomes following lumbar fusion surgery (LFS) and (2) identify radiographic predictors associated with MCID achievement in DLS patients.

METHODS

A total of 91 single-level DLS patients who underwent LFS and had a minimum of 1-year follow-up were enrolled in this study. The assessed radiographic parameters included thoracic kyphosis, lumbar lordosis (LL), segmental lumbar lordosis (SLL), slip percentage, sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and sagittal vertical axis. Changes in radiographic parameters were determined by subtracting the preoperative value from the final follow-up measurement. Clinical outcomes were assessed using the Oswestry Disability Index (ODI) and the visual analog scale (VAS) for both back and leg pain. MCID values were set at 10 points for ODI, 2.1 points for VAS back pain, and 2.8 points for VAS leg pain. Patients were assigned to the reached MCID (rMCID) and missed MCID (mMCID) groups based on the postoperative (post-op) recovery of clinical outcomes.

RESULTS

At the last follow-up, 68.1% (62/91), 72.5% (66/91), and 76.9% (70/91) of patients reached MCID for ODI, VAS back pain, and VAS leg pain, respectively. Concerning ODI, the rMCID group exhibited higher post-op LL (47.93° vs. 42.95°, P = 0.044), higher post-op SLL (17.08° vs. 14.41°, P = 0.032), higher post-op SS (34.46° vs. 30.63°, P = 0.027), higher ∆LL (5.90° vs. 2.44°, P = 0.017), higher ∆SLL (4.63° vs. - 1.03°, P < 0.001), higher ∆SS (4.76° vs. 1.23°, P = 0.002), lower post-op PT/PI (36.95% vs. 42.01%, P = 0.049), lower ∆PT (- 3.71° vs. 1.05°, P < 0.001), lower ∆PT/PI (- 7.45% vs. 1.97%, P < 0.001), and lower ∆PI-LL (- 5.43° vs. - 3.71°, P = 0.011) than the mMCID group. Regarding VAS back pain, the rMCID group showed higher post-op SLL (17.06° vs. 14.05°, P = 0.021), higher post-op SS (34.34° vs. 30.33°, P = 0.027), higher ∆SLL (3.93° vs. - 0.09°, P < 0.001), and lower ∆PT (- 2.91° vs. - 0.30°, P = 0.039) than the mMCID group. For VAS leg pain, higher ∆SLL (3.55° vs. 0.41°, P = 0.003) was observed in the rMCID group than in the mMCID group. Multivariate logistic regression analysis revealed that higher ∆SLL, higher ∆SS, and higher post-op SS were independent predictors for the achievement of MCID in patients with DLS.

CONCLUSION

DLS patients who reached MCID following LFS demonstrated improved post-op spinopelvic alignment. Higher ∆SLL, higher ∆SS, and higher post-op SS were the critical parameters associated with MCID achievement in patients with DLS.

Segmental Sagittal Alignment in Lumbar Spinal Fusion: A Review of Evidence-Based Evaluation of Preoperative Measurement, Surgical Planning, Intraoperative Execution, and Postoperative Evaluation

BACKGROUND AND OBJECTIVES

Maintaining and restoring global and regional sagittal alignment is a well-established priority that improves patient outcomes in patients with adult spinal deformity. However, the benefit of restoring segmental (level-by-level) alignment in lumbar fusion for degenerative conditions is not widely agreed on. The purpose of this review was to summarize intraoperative techniques to achieve segmental fixation and the impact of segmental lordosis on patient-reported and surgical outcomes.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, PubMed, Embase, Cochrane, and Web of Science databases were queried for the literature reporting lumbar alignment for degenerative lumbar spinal pathology. Reports were assessed for data regarding the impact of intraoperative surgical factors on postoperative segmental sagittal alignment and patient-reported outcome measures. Included studies were further categorized into groups related to patient positioning, fusion and fixation, and interbody device (technique, material, angle, and augmentation).

RESULTS

A total of 885 studies were screened, of which 43 met inclusion criteria examining segmental rather than regional or global alignment. Of these, 3 examined patient positioning, 8 examined fusion and fixation, 3 examined case parameters, 26 examined or compared different interbody fusion techniques, 5 examined postoperative patient-reported outcomes, and 3 examined the occurrence of adjacent segment disease. The data support a link between segmental alignment and patient positioning, surgical technique, and adjacent segment disease but have insufficient evidence to support a relationship with patient-reported outcomes, cage subsidence, or pseudoarthrosis.

CONCLUSION

This review explores segmental correction's impact on short-segment lumbar fusion outcomes, finding the extent of correction to depend on patient positioning and choice of interbody cage. Notably, inadequate restoration of lumbar lordosis is associated with adjacent segment degeneration. Nevertheless, conclusive evidence linking segmental alignment to patient-reported outcomes, cage subsidence, or pseudoarthrosis remains limited, underscoring the need for future research.

Radiographic and surgery-related predictive factors for increased segmental lumbar lordosis following lumbar fusion surgery in patients with degenerative lumbar spondylolisthesis

OBJECTIVE

This study aimed to evaluate preoperative (pre-op) radiographic characteristics and specific surgical interventions in patients with degenerative lumbar spondylolisthesis (DLS) who underwent lumbar fusion surgery (LFS), with a focus on analyzing predictors of postoperative restoration of segmental lumbar lordosis (SLL).

METHODS

A retrospective review at a single center identified consecutive single-level DLS patients who underwent LFS between 2016 and 2022. Radiographic measures included disc angle (DA), SLL, lumbar lordosis (LL), anterior/posterior disc height (ADH/PDH), spondylolisthesis percentage (SP), intervertebral disc degeneration, and paraspinal muscle quality. Surgery-related measures included cage position, screw insertion depth, spondylolisthesis reduction rate, and disc height restoration rate. A change in SLL ≥ 4° indicated increased segmental lumbar lordosis (ISLL), and unincreased segmental lumbar lordosis (UISLL) < 4°. Propensity score matching was employed for a 1:1 match between ISLL and UISLL patients based on age, gender, body mass index, smoking status, and osteoporosis condition.

RESULTS

A total of 192 patients with an average follow-up of 20.9 months were enrolled. Compared to UISLL patients, ISLL patients had significantly lower pre-op DA (6.78° vs. 11.84°), SLL (10.73° vs. 18.24°), LL (42.59° vs. 45.75°), and ADH (10.09 mm vs. 12.21 mm) (all, P < 0.05). ISLL patients were predisposed to more severe intervertebral disc degeneration (P = 0.047) and higher SP (21.30% vs. 19.39%, P = 0.019). The cage was positioned more anteriorly in ISLL patients (67.00% vs. 60.08%, P = 0.000), with more extensive reduction of spondylolisthesis (- 73.70% vs. - 56.16%, P = 0.000) and higher restoration of ADH (33.34% vs. 8.11%, P = 0.000). Multivariate regression showed that lower pre-op SLL (OR 0.750, P = 0.000), more anterior cage position (OR 1.269, P = 0.000), and a greater spondylolisthesis reduction rate (OR 0.965, P = 0.000) significantly impacted SLL restoration.

CONCLUSIONS

Pre-op SLL, cage position, and spondylolisthesis reduction rate were identified as significant predictors of SLL restoration after LFS for DLS. Surgeons are advised to meticulously select patients based on pre-op SLL and strive to position the cage more anteriorly while minimizing spondylolisthesis to maximize SLL restoration.

Fusion with and without lever reduction in degenerative lumbar spondylolisthesis: a retrospective study

BACKGROUND

The reduction of slipped vertebra is often performed during surgery for degenerative lumbar spondylolisthesis (DLS). This approach, while potentially improving clinical and radiological outcomes, also carries a risk of increased complications due to the reduction process. To address this, we introduced an innovative lever reduction technique for DLS treatment. This study aims to investigate the clinical efficacy, radiological outcomes, and complications of fusion with or without lever reduction.

METHODS

We conducted a retrospective review of prospectively collected data from a registry of patients who underwent lumbar fusion surgery for DLS, with a follow-up of at least 24 months. Self-reported measures included visual analog scale (VAS) for back or leg pain, Oswestry Disability Index (ODI), and the achievement of minimal clinically important difference (MCID). Radiological assessments encompassed spondylolisthesis percentage (SP), focal lordosis (FL), and lumbar lordosis (LL). Complications were categorized using the modified Clavien-Dindo classification (MCDC) scheme. Patients were assigned to the reduction group (RG) and non-reduction group (NRG) based on the application of the lever reduction technique. Clinical and radiological outcomes at baseline, immediately after surgery, and at the last follow-up were compared.

RESULTS

A total of 281 patients were analyzed (123 NRG, 158 RG). Baseline patient demographics, comorbidities, and surgical characteristics were similarly distributed between groups except for operating time (NRG 129.25 min, RG 138.04 min, P = .009). Both groups exhibited significant clinical improvement after surgery (all, P = .000), with no substantial difference between groups (VAS, ODI, or the ability to reach MCID). Patients in RG showed statistically lower SP and higher FL during follow-up (all, P = .000). LL was comparable at different time points within each group or at the same time point between the two groups (all, P > .050). The overall complication rate (NRG 38.2%, RG 27.2%, P = .050) or specific complication rates per MCDC were similar between groups (all, P > .050). Patients in RG were predisposed to a lower risk of adjacent segment degeneration (ASDeg) (NRG 9.8%, RG 6.3%, P = .035).

CONCLUSIONS

There were no significant differences in postoperative measures such as VAS scores for back and leg pain, ODI, the ability to reach MCID, overall complication rate, or specific complication rates per MCDC between surgical approaches. However, fusion with lever reduction demonstrated a notable advantage in restoring segmental spinal sagittal alignment and reducing the occurrence of ASDeg compared to in situ fusion.

Do On-Table Radiographs Predict Postoperative Sagittal Alignment after Posterior Lumbar Fusion?

OBJECTIVE

To determine if intraoperative on-table lumbar lordosis and segmental lordosis correlate with postoperative lordosis following single-level posterolateral decompression and fusion (PLDF) or transforaminal lumbar interbody fusion (TLIF).

METHODS

Electronic medical records were reviewed for patients ≥18 years old who underwent PLDF or TLIF between 2012 and 2020. Lumbar lordosis and segmental lordosis were compared between pre-, intra-, and postoperative radiographs using paired t tests. Significance was set at P < 0.05.

RESULTS

A total of 200 patients met inclusion criteria. No significant differences in preoperative, intraoperative, or postoperative measurements were found between groups. Patients who underwent PLDF experienced less disc height loss over 1 year postoperatively (PLDF: 0.45 ± 0.9 mm vs. TLIF: 1.2 ± 1.4 mm, P < 0.001). Lumbar lordosis significantly decreased between intraoperative to postoperative radiographs at 2-6 weeks for PLDF (Δ: -4.0°, P < 0.001) and TLIF (Δ: -5.6°, P < 0.001), but no change was identified between the intraoperative and >6 month postoperative radiographs for PLDF (Δ: -0.3°, P = 0.634) or TLIF (Δ: -1.6°, P = 0.087). Segmental lordosis significantly increased from the preoperative to post-instrumentation intraoperative radiographs for PLDF (Δ: 2.7°, P < 0.001) and TLIF (Δ: 1.8°, P < 0.001), but it subsequently decreased at the final follow up for PLDF (Δ: -1.9°, P < 0.001) and TLIF (Δ: -2.3°, P < 0.001).

CONCLUSIONS

Subtle decreases in lumbar lordosis may be noticed in early postoperative radiographs compared with intraoperative images on Jackson operative tables. However, these changes are not present at 1-year follow-up as lumbar lordosis increases to a similar level as intraoperative fixation.

Imaging analysis and predictive nomogram construction for degenerative lumbar spondylolisthesis with severe clinical symptom based on propensity score matching

Intervertebral disc degeneration, local lumbar segmental morphology changes, and atrophy of multifidus muscle have been considered to be associated with degenerative lumbar spondylolisthesis. However, there remains a great deal of controversy. To further investigate their relationship with degenerative lumbar spondylolisthesis, we conducted a retrospective study that included 67 patients with degenerative spondylolisthesis and 182 control subjects. Propensity score matching was employed to match the case group and the control group. Disc height was evaluated by the anterior disc height index (DHIA) and posterior disc height index (DHIP). Local lumbar segmental morphology was assessed by segmental lordosis (SL). The fatty infiltration and atrophy of multifidus muscle was evaluated by multifidus muscle net content (MFNC). Our results indicate that DHIA, DHIP, SL, and MFNC in the case group were significantly lower than in the control group. Furthermore, the DHIA, DHIP, and MFNC of the slipped segment (L4/5) were lower than those of the non-slipped segment (L3/4). Correlation analysis showed a high relationship between DHIA and MFNC and the degree of degenerative lumbar spondylolisthesis. Logistic regression analysis revealed that DHIA and MFNC might act as protective factors against the development of degenerative lumbar spondylolisthesis. Additionally, a prognostic nomogram was developed and validated to assess the likelihood of patients with severe symptoms requiring surgical intervention.

A Short-Term Assessment of Lumbar Sagittal Alignment Parameters in Patients Undergoing Anterior Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To determine if intraoperative on-table lumbar lordosis (LL) and segmental lordosis (SL) coincide with perioperative change in lordosis.

SUMMARY OF BACKGROUND DATA

Improvements in sagittal alignment are believed to correlate with improvements in clinical outcomes. Thus, it is important to establish whether intraoperative radiographs predict postoperative improvements in LL or SL.

MATERIALS AND METHODS

Electronic medical records were reviewed for patients ≥18 years old who underwent single-level and two-level anterior lumbar interbody fusion with posterior instrumentation between 2016 and 2020. LL, SL, and the lordosis distribution index were compared between preoperative, intraoperative, and postoperative radiographs using paired t tests. A linear regression determined the effect of subsidence on SL and LL.

RESULTS

A total of 118 patients met inclusion criteria. Of those, 75 patients had one-level fusions and 43 had a two-level fusion. LL significantly increased following on-table positioning [delta (Δ): 5.7°, P <0.001]. However, LL significantly decreased between the intraoperative to postoperative radiographs at two to six weeks (Δ: -3.4°, P =0.001), while no change was identified between the intraoperative and more than three-month postoperative radiographs (Δ: -1.6°, P =0.143). SL was found to significantly increase from the preoperative to intraoperative radiographs (Δ: 10.9°, P <0.001), but it subsequently decreased at the two to six weeks follow up (Δ: -2.7, P <0.001) and at the final follow up (Δ: -4.1, P <0.001). On linear regression, cage subsidence/allograft resorption was predictive of the Δ SL (β=0.55; 95% confidence interval: 0.16-0.94; P =0.006), but not LL (β=0.10; 95% confidence interval: -0.44 to 0.65; P =0.708).

CONCLUSION

Early postoperative radiographs may not accurately reflect the improvement in LL seen on intraoperative radiographic imaging, but they are predictive of long-term lumbar sagittal alignment. Each millimeter of cage subsidence or allograft resorption reduces SL by 0.55°, but subsidence does not significantly affect LL.

LEVELS OF EVIDENCE

4.

The impact of interbody approach and lumbar level on segmental, adjacent, and sagittal alignment in degenerative lumbar pathology: a radiographic analysis six months following surgery

BACKGROUND CONTEXT

Interbody fusion, including: transforaminal (TLIF), posterior (PLIF), anterior (ALIF), and lateral (LLIF); effectively treat lumbar degenerative pathology and provide spinopelvic balance. Although the decision on surgical approach and technique are multifactorial and patient specific, the impact of the interbody approach on segmental and adjacent level lordosis could be an important factor to consider during pre-operative planning to achieve pre-specified alignment goals.

PURPOSE

The purpose of this study is to compare the 6-month postoperative radiographic outcomes in the lumbar spine following 1 to 2 level transforaminal (TLIF), posterior (PLIF), anterior (ALIF), and lateral (LLIF) interbody fusions at the L3-4, L4-5, and L5-S1 levels. As our primary outcome, we evaluated the change in segmental lordosis at the level of fusion in ALIF/LLIF approaches compared to TLIF/PLIF. Secondarily, we evaluated the pelvic incidence to lumbar lordosis (PI-LL) mismatch and examined the compensatory lordotic changes at the adjacent levels 6 months following surgery.

STUDY DESIGN

Retrospective cohort.

PATIENT SAMPLE

This retrospective study included 18 centers of various practice settings across the United States. Patients were included in the study if they underwent a one- or two-level primary lumbar fusion for degenerative pathology.

OUTCOMES MEASURES

Measurements of the pre-operative and 6-month post-operative lumbar AP and lateral lumbar plain radiographs included: pelvic incidence (PI), pelvic tilt, lumbar lordosis from L1-S1 (LL), as well as segmental lordosis (SL) of each segment between L1-S1.

METHODS

Due to there being 2 evaluated time points, patients were then grouped based on alignment into categories of preserved, restored, not corrected, and worsened.

RESULTS

474 patients underwent 608 levels of fusion. ALIF/LLIF resulted in significantly more segmental lordosis compared to TLIF/PLIF procedures at both L4-5 and L5-S1 (p<.001). Overall, ALIF/LLIF resulted in significantly more global lumbar lordotic alignment change compared to TLIF/PLIF (p=.01). Whether patients' alignment was preserved versus worsened was not significantly predicted by type of procedure. Similarly, whether patients' alignment was restored versus not corrected was not significantly predicted by type of procedure. Finally, anterior approaches resulted in decreased lordosis at adjacent levels, thus resulting in a more neutral position.

CONCLUSION

In this large multicenter retrospective study of 1 to 2 level interbody fusion surgeries, we identified that A/LLIF procedures at L4-L5 and L5-S1 resulted in greater segmental lordosis restoration and PI-LL mismatch improvement compared to T/PLIF procedures. A/LLIF may also significantly reduce lordosis (compared to T/PLIF) at the adjacent levels in a fashion that serves to reduce the lumbar lordosis that may have been increased at the fused level.

A retrospective comparative study of postoperative sagittal balance in isthmic L5–S1 spondylolisthesis using single segment or two-segment pedicle screw fixation

Objective

To compare the radiographic parameters and clinical outcomes of isthmic L5–S1 spondylolisthesis with single segment or two-segment pedicle screw fixation.

Methods

Between January 2018 and January 2019, a total of 76 patients with isthmic L5–S1 spondylolisthesis were included in this study. All patients were treated with varying numbers of pedicle screw fixation with single-segment fusion during posterior lumbar interbody fusion (PLIF). Patients were divided into two groups, based on the number of pedicle screws placed during fixation, namely, 4 screws (4S) group and 6 screws (6S) group. Subsequently, the sagittal balance parameters were measured, which included slippage degree (SD), lumbar lordosis (LL), segmental lordosis (SL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and sagittal vertical axis (SVA). Clinical functional outcomes were assessed using the visual analog scale (VAS) for back pain and the oswestry disability index (ODI) scores.

Results

The 4S group comprised of 10 males and 27 females, with a median age of 55.2 ± 10.8 years old and a mean follow-up of 16.95 ± 4.16 months. The 6S group comprised of 14 males and 25 females, with a median age of 58.1 ± 7.5 years old and a median follow-up of 17.33 ± 3.81 months. No significant differences were evident in all preoperative parameters between both groups. In contrast, the postoperative LL, SL, PT, SS, and SD values increased significantly, compared to the preoperative values in both groups (all P < 0.05). At the last follow-up, the 6S group exhibited better correction in LL, SL, and PT, relative to the 4S group (all P < 0.05). A significant SD difference was observed between both groups at all points post surgery (P < 0.05). The postoperative slip correction rate was significantly larger in the 6S group, compared to the 4S group (P < 0.05). The postoperative VAS and ODI scores of both groups improved significantly, when compared to the preoperative scores (both P < 0.05). However, there were no significant differences in the ODI and VAS scores between the two groups at all time points.

Conclusions

The clinical outcomes of both approaches appeared to be satisfactory. In terms of short-term outcomes, the 6S group exhibited better spinal sagittal restoration and stability than the 4S group.

Predictive Factors Affecting Surgical Outcomes in Patients with Degenerative Lumbar Spondylolisthesis

STUDY DESIGN

Post-hoc analysis of 5-year follow-up data from a prospective randomized multicenter trial.

OBJECTIVE

The purpose of this study was to identify preoperative factors that predict poor postoperative outcomes and define clinically important abnormal instabilities in degenerative lumbar spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Current evidence regarding prognostic factors affecting clinical outcomes after surgery for degenerative lumbar spondylolisthesis is still limited. Moreover, there is no consensus regarding parameters that define clinically important abnormal instability in patients with degenerative lumbar spondylolisthesis.

METHODS

This post-hoc analysis from a prospective randomized trial that compared the effectiveness of decompression, decompression with fusion, and decompression with stabilization for degenerative lumbar spondylolisthesis at the L4/5 level included 70 patients with a 5-year follow-up period. We investigated the correlation between the postoperative recovery rate and preoperative radiographic parameters. We then investigated differences between the good recovery and poor recovery groups.

RESULTS

Japanese Orthopaedic Association and visual analogue scale scores improved postoperatively. Of the 70 patients analyzed, 13 were judged to be in the poor recovery group based on their recovery rate. The recovery rate significantly correlated with the intervertebral angle at L4/5. Univariate analysis showed that while the degree of vertebral slippage and the presence of angulation were not associated with poor recovery, the intervertebral angle at L4/5 and the presence of translation were associated with poor recovery. Lastly, multiple stepwise logistic regression analysis revealed the intervertebral angle at L4/5 and the presence of translation as independent predictors of poor recovery after surgery for lumbar degenerative spondylolisthesis.

CONCLUSION

While the degree of vertebral slippage and the presence of angulation were not associated with poor recovery after surgery for lumbar degenerative spondylolisthesis, postoperative outcomes were associated with the intervertebral angle and the presence of translation. Careful preoperative measurement of these factors may help to predict poor postoperative outcomes.Level of Evidence: 3.

Lumbar degenerative disease after oblique lateral interbody fusion: sagittal spinopelvic alignment and its impact on low back pain

Background

We determined the incidence and risk factors of low back pain (LBP) in patients with lumbar degenerative disease after single-level oblique lateral interbody fusion (OLIF).

Methods

We retrospectively reviewed 120 lumbar degenerative disease patients who underwent single-level OLIF. We compared preoperative and postoperative radiographic parameters, including segmental lordosis (SL), lumbar lordosis (LL), disk height (DH), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), thoracic kyphosis (TK), and C7-sagittal vertical axis (SVA). Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) scores and visual analog scale (VAS) scores for back and leg pain. All patients were followed up for at least 2 years.

Results

Thirty-eight patients had postoperative LBP (VAS score for back pain ≥3; LBP group); the remaining 82 patients were in the non-LBP group. Age (P = 0.082), gender (P = 0.425), body mass index (P = 0.138), diagnosis (degenerative spondylolisthesis vs. lumbar spinal stenosis; P = 0.529), surgical level (P = 0.651), blood loss (P = 0.889), and operative time (P = 0.731) did not differ between the groups. In both groups, the ODI and VAS scores for back pain and leg pain significantly improved at the final follow-up compared with the preoperative scores (P = 0.003). Except for the VAS score for back pain (P = 0.000), none of the scores significantly differed between the two groups at the final follow-up (P > 0.05). In the non-LBP group, LL, SL, DH, TK, and SS significantly improved, while PT and C7-SVA significantly decreased at the final follow-up as compared with the preoperative values. In both groups, DH significantly improved postoperatively, with no significant between-group difference (P = 0.325). At the final follow-up, LL, PI-LL mismatch, PT, and C7-SVA showed significantly greater improvement in the non-LBP group than in the LBP group (P < 0.05). Multivariate analysis identified PT, PI-LL mismatch, and C7-SVA as significant risk factors for LBP after OLIF.

Conclusion

OLIF for single-level lumbar degenerative disease had satisfactory clinical outcomes. PT, PI-LL mismatch, and C7-SVA were significant risk factors for postoperative LBP. Patients with appropriately decreased PT, improved C7-SVA, and PI-LL match experienced less LBP.

[Effect of percutaneous kyphoplasty on lumbar-pelvic correlation in osteoporotic vertebral compressive fractures]

OBJECTIVE

To explore the effect of percutaneous kyphoplasty (PKP) on lumbar-pelvic correlation in osteoporotic vertebral compressive fracture (OVCF).

METHODS

According to the inclusion criteria, 63 patients with primary osteoporosis between January 2012 and June 2017 were selected as the control group and 67 patients with single-segment lumbar OVCF receiving PKP and complete clinical data were included as the observation group. There was no significant difference in gender, age, and lumbar spine bone density between the two groups ( P>0.05). The visual analogue scale (VAS) score and Oswestry Disability Index (ODI) score were used to assess lumbar pain and function before operation and at 3 days after operation in the observation group; lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were measured in lumbar lateral X-ray films which were taken before PKP and at 1 month after PKP. The same parameters were measured in the lumbar lateral X-ray films which were taken at the time of initial diagnosis in the control group.

RESULTS

All patients were followed up 3-24 months with an average of 5.8 months in the observation group. The VAS score decreased from 5.6±1.8 before PKP to 2.8±1.3 at 3 days after PKP ( t=14.082, P=0.000); ODI decreased from 50.1%±5.0% before PKP to 18.2%±1.8% ( t=47.011, P=0.000). Compared with the control group, the LL, PI, and SS decreased and the PT increased in the observation group, and only the difference in LL between the two groups was significant ( P<0.05). In the observation group, the LL and SS significantly increased ( P<0.05) and PT significantly decreased ( P<0.05) at 1 month after operation when compared with preoperative ones, and PI decreased, but the difference was not significant ( P>0.05). In the control group, LL was positively correlated with PI and SS ( P<0.05); PI was positively correlated with PT and SS ( P<0.05). In the observation group, PI was positively correlated with SS ( P<0.05) before and after PKP.

CONCLUSION

OVCF patients lost the specific lumbar-pelvic correlation. PKP can restore lumbar lordosis, but it still can not restore the normal physiological fitting.