Sagittal Spinopelvic Alignment in the Standing and Prone Positions of Patients with Old Traumatic Thoracolumbar Kyphosis: Relationship with Immediately Postoperative Parameters

OBJECTIVE

The aim of this study was to investigate the changes in spine-pelvis sagittal parameters from the standing position to the prone position and to study the relationship between sagittal parameters and immediately postoperative parameters.

METHODS

Thirty-six patients with old traumatic spinal fracture combined with kyphosis were enrolled. The preoperative standing position, prone position, and postoperative sagittal parameters of the spine and pelvis, including the local kyphosis Cobb angle (LKCA), thoracic kyphosis angle (TKA), lumbar lordosis angle (LLA), sacral slope (SS), pelvic tilt (PT), pelvic incidence minus lumbar lordosis angle (PI-LLA), and sagittal vertebral axis (SVA), were measured. The data of kyphotic flexibility and correction rate werecollected and analyzed. The parameters of the preoperative standing position, prone position and postoperative sagittal position were analyzed statistically. Correlation analysis and regression analysis of the preoperative standing and prone sagittal parameters and postoperative parameters were conducted.

RESULTS

There were significant differences in the preoperative standing position, prone position, and postoperative LKCA and TK. Correlation analysis showed that preoperative sagittal parameters of the standing position and prone position were all correlated with postoperative homogeneity. Flexibility was not related to the correction rate. Regression analysis showed preoperative standing, prone LKCA, and TK were linear with postoperative standing.

CONCLUSIONS

The LKCA and TK of old traumatic kyphosis obviously changed from the standing position to the prone position, which were linear with postoperative LKCA and TK and can be used to predict postoperative sagittal parameters. This change should be taken into account in the surgical strategy.

Rebound phenomenon and its risk factors after hemiepiphysiodesis using tension band plate in children with coronal angular deformity

BACKGROUND

This study was performed to evaluate the rebound phenomenon after the correction of coronal angular deformity by hemiepiphysiodesis using tension band plate in children and to identify its risk factors.

METHODS

We reviewed 50 children (mean age, 11.0 ± 2.5 years) with 94 physes who had undergone hemiepiphysiodesis using tension band plate due to coronal angular deformity of the lower limb. Patients' demographic data including sex, age at initial surgery and plate removal, affected bone (distal femur or proximal tibia), affected side, and body mass index were collected. The mechanical lateral distal femoral angle (mLDFA) and the mechanical medial proximal tibial angle (mMPTA) were measured from the teleradiogram, Physes were divided into rebound and non-rebound group, and rebound group was defined as the physes which had  ≥  5° of mLDFA or mMPTA returning to its original deformity. Generalized estimating equation based multivariable analysis was used to identify the risk factors for the rebound phenomenon after the deformity correction.

RESULTS

A total of 41 physes classified into rebound group and 53 physes into non-rebound group. There were significant differences in the age at initial surgery (p = 0.004), the age at implant removal (p = 0.002), the amount of correction (p = 0.001), and the rate of correction (p < 0.001) between two groups. The rate of correction was significantly associated with the rebound phenomenon (p = 0.044). The risk of rebound phenomenon was 1.2-fold higher as the rate of correction increased by 1° per year. The cutoff values of the correction rate between the two groups were 6.9°/year (p < 0.001).

CONCLUSIONS

This study showed that the rebound group had younger age and faster correction rate than those in the non-rebound group. In addition, the correction rate for deformity was a significant risk factor for the rebound phenomenon after hemiepiphysiodesis using the tension band plate. Close monitoring after implant removal is required for children who have a rapid correction rate over 7°/year.

Degree of coronal alignment correction can't predict knee function in total knee replacement

BACKGROUND

Whether neutral alignment brings better clinical outcomes is controversial. Consideration of the preoperative knee condition of patients and some limitations of previous studies, we suggested that other index may be more important than a generic target of 0° ± 3° of a neutral axis to reflect changes in coronal alignment after total knee replacement (TKR). The purpose of this study was to explore the relationship between alignment and functional outcome with a new grouping method and the concept of correction rate.

METHODS

The study included 358 knees, the mean follow-up period was 3.62 years. A new grouping method was adopted to divide patients into three groups based on the degree of correction of mechanical femoral-tibial angle (MFTA): under-correction (n = 128), neutral (n = 209) and over-correction (n = 21). Hospital for Special Surgery (HSS) score were compared among the 3 groups (ANOVA with or without LSD t-test). In addition, we also attempt to further explore whether the concept of correction rate can predict postoperative functional score (Simple linear correlation analysis).

RESULTS

HSS score showed significant improvement in all groups. There was no difference in HSS score (88.27 vs 88 vs 85.62) (p = 0.88) or incremental scores (26.23 vs 25.22 vs 22.88) (p = 0.25) based on the postoperative alignment category for the degree of correction of MFTA at the last follow-up. The correlational analyses also didn't show any positive results (r = -0.01 p = 0.95, r = -0.01 p = 0.97, r = 0.11 p = 0.15, r = 0.01 p = 0.90).

CONCLUSION

Categorization of optimal coronal alignment after TKR may be impractical. But we still believe that the concept of correction rate and new grouping method are worthy of research which can reflects the preoperative knee condition and the change of coronal alignment. Perhaps it can be better used in TKR in the future.

LEVEL OF EVIDENCE

III.

Matching correction of main and compensatory curves is critical for immediate postoperative coronal balance in correction of severe adult idiopathic scoliosis

PURPOSE

To analyze the correlation between immediate postoperative coronal imbalance and the matching degree of the correction rates of the main curve and compensatory curves in the surgical treatment of severe adult idiopathic scoliosis.

METHODS

Patients were categorized into three types based on the preoperative coronal balance status (type A = balance, type B = shifted to cave side and type C = shifted to convex side), and each type was further divided into two subgroups based on the postoperative coronal balance status (balance and imbalance). Different coronal parameters before and after operations were calculated and compared.

RESULTS

The rate of postoperative CIB was highest in type C patients (53.8%) and lowest in type A patients (31.5%). To avoid postoperative CIB, the value of the postoperative CR_main should fall within the range of 1.001 × CR_comp ± 2.84% in type A patients, 1.112 × CR_comp + 3.3% ± 5.02% in type B patients and 0.907 × CR_comp - 2.5% ± 4.38% in type C patients.

CONCLUSION

Mismatch between the correction rates of the main curve and compensation curves is a critical cause of immediate postoperative CIB. The relatively equal correction of the main curve and compensatory curves is essential for type A patients to achieve postoperative coronal balance, while the correction rate of the main curve should be higher than the compensatory curves in type B patients and vice versa in type C patients. Three formulas for the three different types were developed to provide helpful guidance information for surgical planning.

Predictive factors for correction rate in severe idiopathic scoliosis (Cobb angle ≥ 90°): an analysis of 128 patients

PURPOSE

Knowledge on the factors affecting the correction rate (CR) aids in the surgical planning among severe idiopathic scoliosis (IS) patients. This study aimed to investigate the independent factors affecting CR among patients with severe IS (Cobb angle ≥ 90°) who underwent single-staged posterior spinal fusion (PSF).

METHODS

We retrospectively reviewed 128 severe IS patients who underwent single-staged PSF. Factors including age, height, weight, body mass index, Risser sign, Lenke subtypes, preoperative major Cobb angle, side bending major Cobb angle, side bending flexibility (SBF), motion segments of the major curve, AR curve, number of levels fused, screw density, operative time and postoperative major Cobb angle were analysed using linear regression analysis.

RESULTS

The mean age was 15.5 ± 4.5 years with mean Risser sign of 3.1 ± 1.6. The mean preoperative Cobb, SBF, postoperative Cobb and CR were 102.8 ± 12.3°, 37.5 ± 13.7%, 44.4 ± 13.5° and 57.2 ± 10.8%, respectively. From stepwise multiple linear regression analysis, SBF, Risser sign and AR curve were the independent predictive factors for CR, with R² value of 0.345 (p < 0.001). CR can be predicted using the formula: 47.21 + (0.34 × SBF)-(1.47 × Risser sign) + (3.69 × AR), where AR = 1 and non-AR = 0.

CONCLUSION

The flexibility of the major curve, Risser sign and AR curve were the most important predictors for CR in a single-staged PSF among patients with severe IS.

Surgical Outcomes of a New Technique Using a Convex Rod Rotation Maneuver for Adolescent Idiopathic Scoliosis

Introduction

Because of adolescent idiopathic scoliosis (AIS), most surgeons use rod rotation on the concave side for Lenke types 1 and 2 curves. Nevertheless, the accurate placement of pedicle screws within dysplastic pedicles, especially on the concave side, is sometimes challenging. Conversely, there is a concern that apical rotation might be exacerbated after convex rod rotation maneuver (RRM) because the rod is rotated in the same direction as vertebral rotation. This study aims to demonstrate the surgical technique and outcomes of a convex RRM with direct vertebral rotation (DVR) for the correction of AIS.

Technical Note

Multilevel pedicle screws were inserted into the vertebrae. The pre-bent pure titanium rod was set on the convex side and then derotated to nearly 90°. DVR was conducted for the desired vertebrae. Another pre-bent titanium alloy rod, for placement on the concave side, was contoured the same as the rod on the convex side. Using a reduction tube that allowed easier capture of the rod, the rod was connected to the concave side screws. DVR was again conducted for the desired vertebrae. Among the 59 patients, the correction rate of the main thoracic curve in Lenke types 1 and 2 AIS was 75.1% and 65.0%, respectively. The absolute value of the change in apical vertebral rotation between pre- and post-operative computed tomography (CT) scans in Lenke types 1 and 2 curves was 4.8° and 4.2°, respectively.

Conclusions

The convex RRM improved vertebral rotation in Lenke types 1 and 2 AIS. This procedure should be regarded as one of the surgical options for AIS, especially in patients with a narrow pedicle width on the concave side.

短期头盆环牵引配合手术治疗重度脊柱畸形的临床疗效

OBJECTIVE

To evaluate the clinical efficacy of short-term halo-pelvic traction (HPT) combined with surgery in the treatment of severe spinal deformities.

METHODS

In the study, 24 patients diagnosed as severe spinal deformity accepted the treatment of one-stage short-term HPT and two-stage surgery from January 2015 to May 2018 in our orthopedics department. 24 cases (9 males and 15 females) were retrospectively reviewed. The average age of the cohort was (28.8±10.0) years (12－48 years). The height, scoliosis angle, kyphosis angle, the height difference of shoulders, the height difference of crista iliaca, C7PL-CSVL and the perpendicular distance of S1 and the convex point of the patients were assessed at pre-traction, post-traction and post-surgery. The paired t test was used to analyze the difference among pre-traction, post-traction and post-surgery.

RESULTS

The average traction time of 24 cases was (2.5±1.1) weeks (1－5 weeks). The height of pre-traction and post-traction were (141.7±11.2) cm (116-167 cm) and (154.1±9.5) cm (136－176 cm) respectively, showing significant difference (P < 0.05), and the increased height was (12.4±4.6) cm (4－20 cm). The average scoliosis angle before traction was 104.9°±35.0°(25°－158°), and it was significantly decreased in post-traction[64.8°±21.0°(19°－92°)] and post-surgery[39.3°±17.0° (10°-70°)] (P < 0.05). The traction's coronal correction rate was 37.2%±10.9% (11.9%－51.2%) and the total coronal correction rate was 61.9%±12.6%(26.9%-79.0%). The average kyphosis angle before traction was 106.9°±29.2°(54°－163°), and it was significantly decreased in post-traction [63.1°±17.1°(32°－92°)] and post-surgery [39.0°±16.8°(10°－68°)](P < 0.05). The traction's sagittal correction rate was 40.0%±10.7%(16.7%－55.5%) and the total sagittal correction rate was 64.3%±10.7%(49.0%－87.5%). The average C7PL-CSVL before traction was (3.2±2.8) cm, and it was significantly decreased in post-traction [(2.5±2.5) cm] (P < 0.05). The perpendicular distance of S1 and the convex point before traction was (10.5±4.8) cm, and it was significantly decreased in post-traction[(8.4±3.5) cm] (P < 0.05).

CONCLUSION

The one-stage short-term HPT combined with two-stage surgery is a safe and effective procedure for severe spinal deformities. The clinical efficacy is satisfactory and the complication is relatively less.