Influence of Handgrip Strength and Paraspinal Muscles' Volume on Clinical Outcomes in the Patients With Each Sagittal Imbalance and Lumbar Spinal Stenosis

How Does Gravity Influence the Distribution of Lordosis in Patients With Sagittal Malalignment?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Compare the supine vs standing radiographs of patients with adult spinal deformity against ideals defined by healthy standing alignment.

METHODS

56 patients with primary sagittal ASD (SRS-Schwab Type N) and 119 asymptomatic volunteers were included. Standing alignment of asymptomatic volunteers was used to calculate PI-based formulas for normative age-adjusted standing PI-LL, L4-S1, and L1-L4. These formulas were applied to the supine and standing alignment of ASD cohort. Analyses were repeated on a cohort of 25 patients with at least 5 degrees of lumbar flexibility (difference between supine and standing lordosis).

RESULTS

The asymptomatic cohort yielded the following PI-based formulas: PI-LL = -38.3 + .41*PI + .21*Age, L4-S1 = 45.3-.18*Age, L1-L4 = -3 + .48*PI). PI-LL improved with supine positioning (mean 8.9 ± 18.7°, P < .001), though not enough to correct to age-matched norms (mean offset 12.2 ± 16.9°). Compared with mean normative alignment at L1-L4 (22.1 ± 6.2°), L1-L4 was flatter on standing (7.2 ± 17.0°, P < .001) and supine imaging (8.5 ± 15.0°, P < .001). L4-S1 lordosis of subjects with L1-S1 flexibility >5° corrected on supine imaging (33.9 ± 11.1°, P = 1.000), but L1-L4 did not (23.0 ± 6.2° norm vs 2.2 ± 14.4° standing, P < .001; vs 7.3 ± 12.9° supine, P < .001).

CONCLUSIONS

When the effects of gravity are removed, the distal portion of the lumbar spine (i.e., below the apex of lordosis) corrects, suggesting that structural lumbar deformity is primarily proximal.

Evaluation of Sagittal Spinopelvic Alignment on Analgesic Efficacy of Lumbar Epidural Steroid Injection in Geriatric Patients

Background and Objectives: The aim of this study was to evaluate the impact of sagittal imbalance based on pelvic incidence−lumbar lordosis (PI-LL) mismatch on the analgesic efficacy of epidural steroid injection in geriatric patients. Materials and Methods: Patients aged 65 years or older who received lumbar epidural steroid injections under fluoroscopy were enrolled. The cutoff of PI-LL mismatch >20° was used as an indicator of a marked sagittal imbalance. The cross-sectional area of the psoas and paraspinal muscles, as well as the paraspinal fat infiltration grade were measured. A 50% or more decrease in pain score at four weeks after injection was considered as good analgesia. Variables were compared between PI-LL ≤ 20° and >20° groups and multivariate analysis was used to identify factors related to pain relief after injection. Results: A total of 237 patients consisting of 150 and 87 patients in the PI-LL ≤ 20° and >20° groups, respectively, were finally analyzed. Female patients, patients with lumbar surgery history, and the smaller cross-sectional area of the psoas muscles were predominantly observed in patients with sagittal imbalance. There was no difference in analgesic outcome after injection according to the PI-LL mismatch (good analgesia 60.0 vs. 60.9%, p = 0.889). Multivariate analysis showed that pre-injection opioid use, moderate to severe foraminal stenosis, and high-graded paraspinal fat infiltration were significantly associated with poor analgesia after injection. Conclusions: There was no significant correlation between sagittal spinopelvic alignment and pain relief after lumbar epidural steroid injection for geriatric patients.

Predictors for the restoration of the sagittal spinal malalignment in patients with lumbar stenosis after short-segment decompression and fusion surgery

Background

To explore the predictors for the restoration of the sagittal spinal malalignment in the elderly patients with lumbar spinal stenosis (LSS) after short-segment decompression and fusion surgery.

Methods

We retrospectively reviewed 82 LSS patients with sagittal malalignment (SVA ≥ 50 mm or PT ≥ 20° or PI-LL ≥ 20°) who underwent short-segment decompression and fusion surgery between January 2019 and March 2021. Patients’ characteristic, radiographic and paravertebral muscle parameters were assessed. The patients were divided into group A (postoperative malalignment) and B (postoperative alignment) according to whether the postoperative restoration of the sagittal alignment was achieved.

Results

There existed more males in group B than in group A (p = 0.002). The age of group A (73.36 ± 8.02) was greater than that of group B (69.08 ± 6.07, p = 0.009). Preoperative PT in group A (27.40 ± 5.82) was greater than that in group B (19.30 ± 7.32, p < 0.001). The functional cross-sectional area (fCSA) in group A (28.73 ± 4.23) was lower than that in group B (36.94 ± 7.81, p < 0.001). And the fatty infiltration rate (FI) of group A (27.16% ± 5.58%) was higher than that of group B (22.61% ± 5.81%, p = 0.001). The fCSA was negatively correlated with the postoperative PT and PTr (p < 0.05).

Conclusion

Stronger lumbar paravertebral muscles, smaller preoperative PI, PT or PI-LL, male and younger age are the predictors for the restoration of the sagittal spinal malalignment in the elderly LSS patients after short-segment decompression and fusion surgery.

Correlations between paraspinal extensor muscle endurance and clinical outcomes in preoperative LSS patients and clinical value of an endurance classification

Background

Few study has investigated how paraspinal muscle endurance deteriorates in lumbar spinal stenosis (LSS) patients. In addition, little information is available on the relationship between clinical outcomes and the endurance of paraspinal muscles.

Objective

To explore the correlation between paraspinal extensor muscle endurance, quality of life (QOL) and sagittal spinopelvic alignment. Besides, we attempted to propose a paraspinal extensor muscle endurance test (PEMET) classification for identifying the severity of clinical symptoms and sagittal imbalance in LSS patients.

Methods

171 hospitalized LSS patients and 100 healthy controls from the community were prospectively enrolled in this study. The paraspinal extensor endurance test was performed at baseline according to Ito test. The LSS patients were stratified into three groups based on the performance time of endurance test: grade I (<10s); grade II (10–60s); and grade III (>60s). Clinical measures of QOL included the visual analog scale scores (VAS) for back pain and leg pain and the Oswestry Disability Index (ODI). Sagittal alignment was analysed by standing posteroanterior and lateral whole spine X-ray in LSS patients.

Results

The LSS group had a significantly shorter performance time of the endurance test than the control group. The paraspinal muscle endurance significantly correlated with VAS-back, VAS-leg, ODI, pelvic tilt, lumbar lordosis and sagittal vertical axis (SVA; all p < 0.05). In binary logistic regression, the performance time of the endurance test was an independent factor of both poor functional status (ODI >40; p = 0.005, OR = 0.985) and global sagittal imbalance (SVA >50 mm; p = 0.019, OR = 0.985). Based on PEMET classification, moving from the grade III group to the grade I group, there was progressive worsening in VAS-back and ODI (all adjusted p < 0.05). Moreover, the grade I group had significantly greater VAS- leg, less LL and greater SVA than the other two groups (all adjusted p < 0.05).

Conclusion

Paraspinal muscle endurance was associated with QOL and sagittal spinopelvic alignment in LSS patients. A PEMET classification system has been constructed and has shown a correlation with QOL and sagittal imbalance.

Translational potential statement

The PEMET classification system proposed in this study could be available for identifying the severity of clinical symptoms and sagittal imbalance during preoperative evaluation in LSS patients.