Risk factors of revision operation and early revision for adjacent segment degeneration after lumbar fusion surgery: a case-control study

BACKGROUND CONTEXT

Adjacent segment degeneration (ASD) following lumbar fusion operation is common and can occur at varying timepoints after index surgery. An early revision operation for ASD, however, signifies a short symptom-free period and might increase the risk of successive surgeries.

PURPOSE

We aimed to elucidate the overall risk factors associated with revision surgeries for ASD with distinct attention to early revisions.

STUDY DESIGN/SETTING

Retrospective, case-control study.

PATIENT SAMPLE

The study included 86 patients who underwent revision operations for ASD after lumbar fusion in the revision group and 166 patients who did not for at least 5 years after index surgery.

OUTCOME MEASURES

Sagittal parameters, Pfirrmann grading, facet degeneration grading, and disc space height (DSH) of adjacent segments were assessed.

METHODS

Revision operations within 5 years postsurgery were defined as early revision. We compared the revision and no-revision groups as well as the early- and late-revision groups.

RESULTS

The revision group demonstrated a significantly greater preoperative C7-S1 sagittal vertical axis (SVA) (p=.001), postoperative C7-S1 SVA (p<.001), and postoperative pelvic incidence (PI)-lumbar lordosis (LL) (p<.001) than those in the no-revision group. Preoperative DSH of the proximal adjunct segment (p=.001), postoperative PI-LL (p=.014), and postoperative C7-S1 SVA (p=.037) exhibited significant association with ASD in logistic regression analysis. The early-revision group had a significantly higher patient age (p=.001) and a greater number of levels fused (p=.030) than those in the late-revision group. Multivariate Cox regression analysis demonstrated that old age (p=.045), a significant number of levels fused (p=.047), and a narrow preoperative DSH of the proximal adjacent level (p=.011) were risk factors for early revision.

CONCLUSIONS

Postoperative sagittal imbalance, including significant PI-LL and C7-S1 SVA were risk factors for revision operation for ASD but not for early revision. These factors are likely to affect the long-term risk of revision operation due to ASD and thus are not considered risk factors for early revision. Narrow DSH of the proximal adjacent level increased the risks of both revision and early revision surgeries. Moreover, old age and a significant number of levels fused further increased the risk for early revision for ASD.

Correlation between strength/endurance of paraspinal muscles and sagittal parameters in patients with degenerative spinal deformity

BACKGROUND

Sagittal imbalance is a common cause of low back pain and dysfunction in patients with degenerative spinal deformity (DSD), which greatly affects their quality of life. Strength and endurance are important functional physical indexes for assessing muscle condition. However, the correlation between sagittal parameters and paraspinal muscle strength/endurance is not yet clear. The purpose of this study was to analyze the correlation between strength/endurance of paraspinal muscles and sagittal parameters in patients with DSD.

METHODS

There were 105 patients with DSD and 52 healthy volunteers (control group) enrolled. They were divided into the balance group [sagittal vertical axis (SVA) < 5 cm, n = 68] and imbalance group (SVA ≥ 5 cm, n = 37). The maximal voluntary exertion (MVE)/Endurance time (ET) of paravertebral muscles were assessed using the prone position test stand, and the sagittal parameters of the subjects were measured, namely, SVA, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Pearson coefficients were used to assess the correlation between paraspinal muscle MVE/ET and sagittal parameters.

RESULTS

MVE and ET of paravertebral muscles in the control group were significantly higher than those in the balance and imbalance groups (P < 0.05), whereas MVE in the balance group was significantly higher than that in the imbalance group (P < 0.05). SVA in the imbalance group was significantly higher than those in the control and balance groups (P < 0.05). SS and TK in the control group were significantly higher than those in the imbalance group (P < 0.05), and PT and PI in the control group were significantly lower than those in the balance and imbalance groups (P < 0.05). LL in the imbalance group was significantly lower than that in the balance and control groups (P < 0.05). MVE, MVE/BH, and MVE/BW of paraspinal muscles in the imbalance group were negatively correlated with SVA and PT. Moreover, they were positively correlated with LL.

CONCLUSIONS

Deformity may cause the decrease of MVE and ET of paraspinal muscles in the prone position in patients with DSD. Furthermore, the decline in MVE of paraspinal muscles may be a predisposing factor for the imbalance observed. The decrease of MVE/BW of paraspinal muscles may be involved in spinal compensation, and it is a sensitive indicator for sagittal imbalance and lumbar lordosis.

How to make a more optimal surgical plan for Lenke 5 adolescent idiopathic scoliosis patients: a comparative study based on the changes of the sagittal alignment and selection of the lowest instrumented vertebra

BACKGROUND

The treatment of patients with Lenke 5 adolescent idiopathic scoliosis (AIS) is closely related to the pelvic because the spine-pelvis is an interacting whole. Besides, the choice of fusion segment is a significant issue; with the optimal choice, there will be fewer complications and restoring the pelvic morphology to some extent. This study aims to analyze the impact of changes in sagittal parameters and selection of the lowest instrumented vertebra (LIV) on spine and pelvic morphology for better surgical strategy.

METHOD

Ninety-four patients with Lenke 5 AIS who underwent selective posterior thoracolumbar/lumbar (TL/L) curve fusion were included in the study and grouped according to pelvic morphology and position of LIV. Spinopelvic parameters were measured preoperatively, postoperatively, and at the latest follow-up. The patient's preoperative and last follow-up quality of life was assessed with the MOS item short-form health survey (SF-36) and scoliosis research society 22-item (SRS-22).

RESULT

Patients being posterior pelvic tilt had the oldest mean age (P = 0.010), the smallest lumbar lordosis (LL) (P = 0.036), the smallest thoracic kyphosis (TK) (P = 0.399) as well as the smallest proximal junctional angle (PJA) while those being anterior pelvic tilt had the largest PJA. The follow-up TK significantly increased in both groups of anterior and normal pelvic tilt (P < 0.039, P < 0.006) while no significant changes were observed in the posterior pelvic tilt group. When LIV is above L4, the follow-up PJA was larger than other groups (P = 0.049, P = 0.006). When LIV is below L4, the follow-up TK and PT were larger and LL was smaller than other groups(P < 0.05). The SF-36 and SRS-22 scores were better in the LIV = L4 group than in other groups at the last follow-up (P < 0.05).

CONCLUSION

The correction of TK and LL after surgery can improve pelvic morphology. Besides, LIV is best set at L4, which will facilitate the recovery of TK, the improvement of symptoms, and the prevention of complications and pelvic deformities. Level of evidence Level III.

[Clinical observation on correction of abnormal cervical sagittal parameters by cervical pulling method guided by cervical motion segment extension]

OBJECTIVE

To observe the radiological change and curative effect of cervical spondylosis treated with cervical vertebra pulling therapy in young people.

METHODS

A total of 65 patients(shedding in 5 patients and final inclusion in 60 patients) with cervical spondylosis who were treated from January 2018 to September 2019 were randomly divided into treatment group and control group according to the digital table method. There were 30 patients in treatment group, including 14 males and 18 females, aged from 20 to 44 years old with an average of(29.83±6.99) years, who were treated with cervical vertebra pulling therapy(once a week, 4 times in total). The control group consisted of 30 cases, 12 males and 18 females, aged from 18 to 43 years old with an average of (31.77±5.93) years, who received sitting traction therapy(once a week, 4 times in total). The changes of C₂-C₇ Cobb angle, arc-chord distance and T₁ slope (T₁S) in two groups were observed before treatment and 1 month after treatment, for intra-group and inter-group comparison;and the changes of numerical rating scale(NRS) in two groups were observed before treatment and 1, 3 months after treatment, for intra-group and inter-group comparison.

RESULTS

Sixty patients were followed up for (3.2±0.3) months. There were no significant differences in NRS, C₂-C₇ Cobb angle, arc-chord distance and T1S between two groups before treatment (P>0.05). One month after treatment, the NRS, C₂-C₇ Cobb angle, arc-chord distance and T1S were(1.67±0.76) scores, (16.55±6.01)°, (10.95±4.04)mm, (18.95±4.19)° in treatment group and(1.40±0.86) scores, (10.23±5.94) °, (6.11±4.17) mm, (13.34±4.25)° in control group respectively. C₂-C₇ Cobb angle, arc-chord distance and T₁S in treatment group were better than those in control group (P<0.05); there was no significant difference in NRS between two groups (P>0.05). Compared with before treatment, there were statistically significant differences in C2-C7 Cobb angle, arc-chord distance and T1S in treatment group(P<0.05), but no statistically significant differences in control group(P>0.05). Three months after operation, NRS of treatment group was (1.60±0.62) scores and that of control group was (4.17±0.70) scores. The treatment group was better than the control group(P<0.05). The scores of treatment group after treatment were lower than those before treatment(P<0.05), and there was no significant difference in control group before and after treatment(P>0.05).

CONCLUSION

Cervical vertebra pulling method and cervical vertebra sitting traction can relieve the pain symptoms of patients with cervical spondylosis, but the effect of cervical vertebra pulling method is more durable;cervical vertebra pulling method can correct abnormal cervical sagittal parameters.

Variability in stable sagittal vertebra (SSV) during full-length biplanar xrays can affect the choice of fusion levels in patients with adolescent idiopathic scoliosis (AIS)

PURPOSE

Surgical planning for Adolescent Idiopathic Scoliosis (AIS) relies on the coronal and sagittal plane to determine the lowest instrumented vertebra (LIV). Failure to include the stable sagittal vertebra (SSV) within the construct can increase the incidence of postoperative distal junctional kyphosis (DJK). The purpose of this study is to assess the variability of SSV within patients and to identify positional parameters that may lead to its change.

METHODS

This is a case-control study of AIS patients with changes in SSV throughout serial radiographs. Radiographic sagittal parameters and hand positioning for the patients with changes in SSV were compared to patients with stable SSV. Additionally, a subgroup analysis was conducted to compare the positional parameters of only the patients with changes in SSV.

RESULTS

46 patients with a mean age of 15 ± 1.8 years old at the time of surgery were included in this study. 33/76 (43.4%) image pairs were found to have a change in SSV. Positional parameters associated with the more distally measured SSV were found to have a more negative sagittal vertebral axis (p = 0.001), more positive pelvic shift (p = 0.023), and more negative Global Sagittal Axis (p = 0.001) when compared to the more proximally measured SSV.

CONCLUSION

Significant variability exists in the determination of SSV in AIS patients undergoing serial radiographs. Positional parameters associated with the proximal and distally measured SSV also have variability which indicates that posture has a significant impact on this measure. Surgeons need to be aware of SSV variability during preoperative planning and must consider multiple parameters for the determination of LIV.

LEVEL OF EVIDENCE

3.

Analysis of the Effect of Surgical Treatment for the Patients with Hirayama Disease from the Perspective of Cervical Spine Sagittal Alignment

OBJECTIVE

This study was carried out to analyze the surgical effect of cervical spine sagittal alignment for patients with Hirayama disease (HD).

METHODS

Forty-four subjects were retrospectively analyzed for the parameters of cervical spine sagittal alignment. The case group consisted of 23 patients with HD, whereas the control group consisted of 21 healthy adolescent subjects. Pre- and postoperative cervical spine sagittal parameters of the patients with HD were collected; the cervical sagittal parameters of the healthy adolescent subjects were also collected. Sagittal alignment parameters were compared between the patients with HD and the healthy adolescent subjects, and between the pre- and postoperative parameters for the patients with HD.

RESULTS

Forty-four subjects completed the follow-up, with the average follow-up period being 18.0 months. No significant differences were detected between the HD and control groups for clinical parameters (P > 0.05). The preoperative HD group had smaller values compared with the control group in the sagittal parameters of C2-7 cervical lordosis (CL) angle, T1 slope, thoracic inlet angle (TIA), and cervical tilt angle (P < 0.05). For the patients with HD, the preoperative values were smaller compared with the postoperative HD values for the parameters of C2-7 CL angle, T1 slope, and cervical tilt angle (P < 0.05). We found no significant differences between the postoperative patients with HD and the healthy subjects, including C2-7 CL angle, C2-7 sagittal vertical axis, T1 slope, TIA, neck tilt angle, cervical tilt angle, and cranial tilt angle (P > 0.05).

CONCLUSIONS

Patients with HD have sagittal imbalance of the cervical spine compared with age-matched healthy adolescent subjects, and surgical treatment could correct the sagittal imbalance.

Characteristics and correlation analysis of spino-pelvic sagittal parameters in elderly patients with lumbar degenerative disease

Background

Retrospective analysis of the characteristics and correlation of spino-pelvic sagittal parameters in elderly patients with lumbar degenerative disease.

Methods

Eighty-seven patients with lumbar degenerative disease, with an average age of 75.4 years old, were enrolled in the observation group. They were all from the orthopedics department of Beijing Hospital and got enrolled in this study from August 2015 to October 2017. Another 80 volunteers, with an average age of 74.5 years old, were enrolled in the control group. Standing lateral radiographs of the full-length spine were taken for all subjects. The following spino-pelvic sagittal parameters were measured: sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT). Statistical analysis was performed to compare the differences of the parameters between groups, and the correlation analysis was also performed.

Results

SVA, PI, and PT of the observation group were significantly higher than those of the control group (p < 0.01), while LL and SS were significantly lower in the observation group (p < 0.01). No significant differences were found in TK between the two groups. The correlation analyses showed that PI was significantly correlated with SS and PT in both the observation group (p < 0.01) and the control group (p < 0.01), so as the SVA-PI (p < 0.05) and SVA-PT (p < 0.01). SS-PT was also significantly correlated in the observation group (p < 0.01) and in the control group (p < 0.05). LL was significantly correlated with all the other parameters in the observation and control groups, including SVA (p < 0.01; p < 0.01), TK (p < 0.01; p < 0.01), PI (p < 0.01; p < 0.01), SS (p < 0.01; p < 0.01), and PT (p < 0.01; p < 0.01). SVA-SS (p < 0.05), TK-PI (p < 0.05), and TK-SS (p < 0.01) were significantly correlated in the control group but not in the observation group.

Conclusion

Reduced coordination of the spine and pelvis in elderly patients with lumbar degenerative disease was observed. Many of the cases were in the state of sagittal imbalance, with the trunk center of gravity moving forward, the integral sagittal alignment becoming straight, and the pelvic posterior tilt increasing. Pelvic parameters were significantly correlated with each other, which may affect the sagittal curve of the spine. LL was a core parameter that significantly correlated with various sagittal parameters.

Comparing Allografts to Autografts for Maintenance of Cervical Sagittal Parameters and Clinical Outcomes Following Anterior Cervical Discectomy and Fusion With Anterior Cervical Plating

Objective

Current literature has not shown if using either allograft or autograft differentially affects postoperative cervical sagittal parameters. The goal of this study was to compare sagittal alignment and patient-reported outcomes following anterior cervical discectomy and fusion (ACDF) with allograft versus autograft.

Methods

A retrospective cohort analysis of patients who underwent single-level ACDF was conducted. Preoperative, immediate postoperative, and final follow-up radiographic assessments were conducted and included: change in C2–7 lordosis, T1 slope, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, and proximal and distal adjacent segment degeneration (ASD). Patient-reported outcomes were obtained using the Neck Disability Index and visual analogue scale scores for neck and arm.

Results

A total of 404 patients were assessed; 353 using allograft and 51 using autograft. No significant differences existed in demographics. Cervical lordosis improved in both groups without significant changes in SVA. Autograft group had a significantly greater amount of lordosis at the proximal segment on immediate postoperative radiographs and less overall cervical lordosis at final follow-up. Sagittal parameters were similar at each time point without significant changes between the 3-time points. No significant differences existed in radiographic ASD or reoperation rates. Fusion rates exceeded 96% in both groups. No significant differences existed between preoperative, postoperative, or change in patient-reported outcomes between the 2 groups.

Conclusion

Sagittal alignment is maintained following ACDF when using either allograft or autograft. Radiographic evidence of ASD is present in both groups; however, this was not considered clinically significant, given low rates of pseudarthrosis or reoperation. No significant differences exist between groups in terms of patient-reported outcomes.

Radiographic Analysis of Minimally Invasive Transforaminal Lumbar Interbody Fusion versus Conventional Open Surgery on Sagittal Lumbar-Pelvic Alignment for Degenerative Spondylolisthesis

OBJECTIVE

To compare the impact of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with open posterior lumbar interbody fusion (PLIF) on sagittal lumbar-pelvic radiographic parameters for degenerative spondylolisthesis (DS).

METHODS

Of 48 patients with L4 single segmental DS, 25 underwent MIS-TLIF with Quadrant system and 23 underwent conventional open PLIF. Comparisons of data from the preoperative and final follow-up standing lateral lumbar x-rays, with the bilateral femoral heads, of the 2 groups were conducted using the following parameters: slip percentage (SP), lumbar lordosis (LL), pelvic incidence, pelvic tilt (PT), sacral slope, lumbosacral angle, slip angle (SA), and the L1 axis and S1 distance (LASD).

RESULTS

The slip reduction rate (ΔSP) in the OPEN group was significantly higher than in the MIS group (67 ± 34% vs. 37 ± 51%, P = 0.018). The change of SA (ΔSA) in the OPEN group was significantly higher than in the MIS group (3 ± 7° vs. -3 ± 5°, P = 0.003). The change of LASD (ΔLASD) in the OPEN group was significantly lower than in the MIS group (-4 ± 15 mm vs. 4 ± 9 mm, P = 0.033). There were positive correlations between the preoperative SP and LASD, and ΔSA and the change of LL (ΔLL), and a negative correlation between ΔLL and the change of PT (ΔPT).

CONCLUSIONS

For low-grade DS, open PLIF has a higher rate of slip reduction compared to MIS-TLIF, and significantly reduces LASD, therefore, it is more conducive to improving lumbar sagittal balance.

Correlation of cervical sagittal alignment parameters on full-length spine radiographs compared with dedicated cervical radiographs

BACKGROUND

Radiographic parameters to evaluate the cervical spine in adult deformity using 36-inch films have been proposed. While 36-inch films are used to evaluate spinal deformity, dedicated cervical films are more commonly used to evaluate cervical spine pathology. The purpose of this study is to determine correlations between sagittal measures from a dedicated cervical spine radiographs and 36-inch spine radiographs.

METHODS

Patients who had standing cervical and 36-inch radiographs within four weeks of each other were identified. On separate occasions, the following measures were determined: C0-C2, C0-C7, C1-C2 and C2-C7 sagittal Cobb angles; T1 slope; chin-brow-vertical angle (CBVA), C1-C7 sagittal vertical axis (SVA), C2-C7SVA, center of gravity-C7 sagittal vertical axis (COG-C7SVA). Paired t-tests and correlation analyses were done between parameters from the cervical and the 36-inch film.

RESULTS

Radiographic measurements were collected on 40 patients (33 females and 7 males, mean age of 48.9 ± 14.5 years). All correlations were statistically significant at p < 0.001. C0-C2 Cobb had the strongest correlation (r = 0.81) and C2-C7 Cobb had the weakest (r=0.62). Among sagittal balance parameters, COG-C7SVA had the weakest correlation (r = 0.42) and C1-C7SVA (r = 0.64) and the C2-C7SVA (r = 0.65) had strong correlations. The T1 slope and the CBVA had correlation coefficients of 0.74 and 0.91, respectively. There was no statistically significant difference in measures taken from the cervical film and 36-inch film, except for the C0-C7 Cobb (p = 0.000) with a measurement difference of 7° and the T1 tilt (p = 0.000) with a measurement difference of 5°.

CONCLUSION

Except for COG-C7 SVA, strong correlations between most cervical spine parameters taken from a dedicated cervical film and those taken from a 36-inch film were seen. 36-inch radiographs provide a reasonable estimation of cervical sagittal spine parameters and may obviate the need for a dedicated cervical spine radiograph.

Changes of Sagittal Spinopelvic Parameters in Normal Koreans with Age over 50

Study Design

A prospective comparative study.

Purpose

To describe the changes in the spinopelvic parameters on normal Koreans more than 50 years of age.

Overview of Literature

There are differing opinions regarding the changes in the thoracic kyphosis, lumbar lordosis, C7 plumb with age in the elderly population.

Methods

Sagittal standing radiographs of the whole spine including the pelvis in 132 Korean adult male volunteers more than 50 years of age were evaluated prospectively. Volunteers with a history of spine operation, spinal disease, pain in their back or legs, scoliosis, spondylolisthesis, monosegment disc space narrowing, or compression fracture in radiographs were excluded. The following parameters were included: thoracic kyphosis (T5 upper end plate [UEP]-T12 lower end plate [LEP]), thoracolumbar kyphosis (T10 UEP-L2 LEP), lumbar lordosis (T12 LEP-S1 UEP), lower lumbar lordosis (L4 UEP-S1 UEP), sacral slope, pelvic incidence, and the distances from the C7 plumb to the posterosuperior endplate of S1. These parameters in the 6th, 7th and 8th decade groups were compared and the changes in these parameters according to age were examined.

Results

The thoracic kyphosis demonstrated significant differences in the in the three age groups (p = 0.019), and increased with age (r = 0.239, p < 0.006). The other parameters did not show any significant difference or correlation.

Conclusions

Similar global sagittal balances and spinopelvic parameters may be observed in Korean males older than 50 years, with a trend towards increasing thoracic kyphosis with age.