What factors are associated with a better restoration of pelvic version after adult spinal deformity surgery?

INTRODUCTION

Poor restoration of pelvic version after adult spinal deformity (ASD) surgery is associated with an increased risk of mechanical complications and worse quality of life. We studied the factors linked to the improvement of postoperative pelvic version.

MATERIALS AND METHODS

This is a retrospective analysis of a prospective multicenter ASD database. Selection criteria were: operated patients having preoperative severe pelvic retroversion as per GAP score (Relative Pelvic Version-RPV < - 15°); panlumbar fusions to the pelvis; 2-year follow-up. Group A comprised patients with any postoperative improvement of RPV score, and group B had no improvement. Groups were compared regarding baseline characteristics, surgical factors, and postoperative sagittal parameters. Parametric and non-parametric analyses were employed.

RESULTS

177 patients were studied, median age 67 years (61; 72.5), 83.6% female. Groups were homogeneous in baseline demographics, comorbidities, and preoperative sagittal parameters (p > 0.05). The difference in RPV improvement was 11.56º. Group A (137 patients) underwent a higher percentage of ALIF procedures (OR = 6.66; p = 0.049), and posterior osteotomies (OR = 4.96; p < 0.001) especially tricolumnar (OR = 2.31; p = 0.041). It also showed a lower percentage of TLIF procedures (OR = 0.45; p = 0.028), and posterior decompression (OR = 0.44; p = 0.024). Group A displayed better postoperative L4-S1 angle and relative lumbar lordosis (RLL), leading to improved sacral slope (and RPV), and global alignment (RSA). Group A patients had longer instrumentations (11.45 vs 10; p = 0.047) and hospitalization time (13 vs 11; p = 0.045). All postoperative sagittal parameters remained significantly better in group A through follow-up. However, differences between the groups narrowed over time.

CONCLUSIONS

ALIF procedures and posterior column osteotomies improved pelvic version postoperatively, and associated better L4-S1 and lumbar lordosis restoration, indirectly improving all other sagittal parameters. However, these improvements seemed to fade during the 2-year follow-up.

The post-surgical transition in adolescents who have idiopathic scoliosis. A qualitative study

OBJECTIVE

To know the process experienced by adolescents suffering from idiopathic scoliosis when undergoing surgery to correct the physical deformity.

METHOD

Qualitative study with a symbolic interactionism approach. 22 semi-structured interviews were conducted with adolescents who underwent posterior spinal fusion in a third-level hospital in Madrid between May 2019 and January 2021. Taylor and Bogdan's analysis in progress was carried out.

RESULTS

Patients with adolescent idiopathic scoliosis present with a complex simultaneous health/illness and developmental transition. The main inhibitory conditions of the transition are the meanings about: their identity, social, beliefs about surgery, ignorance about the pathology, the surgical process, and their recovery. As facilitating conditions, we find: a positive attitude towards physical, aesthetic, and social change, socioeconomic level, and family support.

CONCLUSIONS

The informants of this study refer that aesthetic affectation and physical limitations are the main elements that cause them discomfort. Surgical intervention is presented as the solution to this situation. Recovery is a critical point in the transition process mainly due to pain. They accept the discomfort suffered during the recovery because they hope to obtain an improvement in the image and physical limitations. The changes and differences they experience during the transition make them think that they will be able to lead a «normal life» to which they constantly refer in their speeches.

Sagittal realignment: surgical restoration of the global alignment and proportion score parameters: a subgroup analysis. What are the consequences of failing to realign?

INTRODUCTION

The Global Alignment and Proportion (GAP) score incorporates three domains directly modified with surgery (relative pelvic version-RPV, relative lumbar lordosis-RLL, lumbar distribution index-LDI) and one indirectly restored (relative spinopelvic alignment-RSA). We analyzed our surgical realignment performance and the consequences of domain-specific realignment failure on mechanical complications and PROMs.

MATERIALS AND METHODS

From an adult spinal deformity prospective multicenter database, we selected patients: fused to pelvis, upper instrumented vertebra at or above L1, and 2 years of follow-up. Descriptive, univariate and multivariate analyses were employed.

RESULTS

The sample included 333 patients. RLL-6w showed the highest success rate (58.3% aligned), but 16.5% of patients were classified in the "Severe hypolordosis" and "Hyperlordosis" subgroups. RPV-6w was the most challenging to realign, with 51.6% moderate or severe retroversion. Regarding RSA-6w, 21.9% had severe positive malalignment. Correct alignment of RPV-6w (p = 0.025) and RSA-6w (p = 0.002) proved to be protective factors against the development of mechanical complications. Severe pelvic retroversion (p = 0.026) and severe positive malalignment (p = 0.007) were risk factors for mechanical complications. RSA-6w "Severe positive malalignment" was associated with less improvement in PROMs: ∆ODI (8.83 vs 17.2; p = 0.011), ∆SRS-22 total (0.54 vs 0.87; p = 0.007), and ∆SF-36PCS (3.47 vs 7.76; p = 0.04); MCID for ODI (37.0 vs 55.5%; p = 0.023), and SRS-22 (40.8 vs 60.1%; p = 0.015); and PASS for ODI (17.6 vs 31.7%; p = 0.047).

CONCLUSIONS

RPV was the most underperformed modifiable parameter. Severe pelvic retroversion and severe positive malalignment influenced the occurrence of mechanical complications. Severe positive malalignment affected PROMs improvement.

Does the use of postoperative brace help preventing mechanical complications following adult deformity surgery?

PURPOSE

There is scarce information regarding the effectiveness of postoperative braces in decreasing mechanical complications and reinterventions following adult deformity surgery.

METHODS

Retrospective matched cohort study from a prospective adult deformity multicenter database. We selected operated patients, fused to the pelvis, > 6 instrumented levels, and minimum 2 year follow-up. Three hundred and eighty patients were separated into two groups (Brace-3 months TLSO-vs No Brace) and then matched controlling for age, gender and frailty. We studied demographic, intraoperative, and postoperative spinopelvic parameters. Both groups were compared regarding complications and reinterventions in the first 2 postoperative years, using univariate and multivariate logistic regression analysis.

RESULTS

We finally analyzed 359 matched patients, mean age of 65.3 ± 8.9 years, frailty-index (0.43 ± 0.15), and mostly females (84%). 224 patients wore a postoperative brace (B) and 135 didn't (NoB). They showed no difference in intraoperative variables and postoperative spinopelvic alignment. They differed (P < 0.05) in: Pelvic incidence (B:58° ± 13 vs NoB:54.5° ± 13); BMI (B:25.8 ± 4 vs NoB:27.4 ± 5); upper instrumented vertebra (B:81.7% T8-L1 vs NoB:72.6% T8-L1), and the use of multiple rods (B:47.3% vs NoB:18.5%). Univariate analysis showed a higher rate of mechanical complications and reinterventions when not using a brace. As well as higher NRS-back and leg pain at 6 weeks. However, multivariate analysis selected the use of multiple rods as the only independent factor protecting against mechanical complications (OR: 0.38; CI 95% 0.22-0.64) and reinterventions (OR: 0.41; CI 95% 0.216-0.783).

CONCLUSION

After controlling for potential confounders, our study could not identify the protective effect of postoperative braces preventing mechanical complications and reinterventions in the first two postoperative years.

Total en bloc spondylectomy in the treatment of postoperative chronic osteomyelitis: a case report

BACKGROUND

Infection of the spine after surgical procedures is one of the most dreaded complications of spinal fusion surgery. Treatment goals are to eradicate the necrotic and infected tissue and to obtain a correct spinal profile. Traditionally many authors have recommended the posterolateral or double approach, anterior and posterior. Total en bloc spondylectomy is a surgical procedure traditionally used to treat primary and metastatic tumors. The use of this surgical procedure in treatment of chronic vertebral osteomyelitis is not clearly defined in literature.

CASE DESCRIPTION

This case involved a 66-year-old female patient with a history of T9-S1 instrumentation after several surgeries, who developed chronic osteomyelitis of T8-T9 with extensive destruction of the vertebral body and severe thoracic kyphosis. After targeted antibiotic therapy, total en bloc spondylectomy of T8-T9 was performed according to the Tomita technique. Necrotic and infected tissues were removed proceeding as if it were chronic osteomyelitis of long bones and performing en bloc resection with clear margins, that is, applying the criteria of oncological surgery to this chronic infection. After resection, the sagittal plane is reconstructed in the affected segment, restoring the normal distance between the two healthy vertebrae and the mechanical stability of the spine.

CONCLUSIONS

Total en bloc spondylectomy in the treatment of extensive infectious lesions with a mechanical component allows performing en bloc resection of infected and necrotic tissue along with biological and mechanical reconstruction. In our case, the complete resection of the infected bone and soft tissues achieved good outcome without complications. We propose total en bloc spondylectomy as a reasonable treatment option in complicated spondylodiscitis progressing to extensive chronic osteomyelitis and compromising spinal stability due to a significant loss of bone material.

Cardiac Cement Embolism After Thoracic Kyphoplasty: Successful Conservative Treatment With 4-Year Follow-Up

BACKGROUND

The present case report describes a complication after a percutaneous spine surgery technique that is highly uncommon in clinical practice: a bone cement cardiac embolism. This rare complication emphasizes the importance of this case, which is also interesting considering the midterm follow-up. Documented cardiac embolisms published in the literature (which are scarce) describe the acute phase of these cases but lack follow-up. There are no systematic reviews on this topic, only case-by-case presentations, and surgeons are not aware of its real implications.

CASE

We report a case of an 84-year-old man who developed sudden thoracic and spinal pain associated with 82% saturation and dyspnea a few hours after 4-level thoracic spine vertebroplasty and kyphoplasty. Imaging revealed multiple bone cement embolisms in his lung and heart. Because the patient was hemodynamically stable, cardiologists recommended conservative treatment with low molecular weight heparin, without embolus removal. At 4-year follow-up, the patient remained asymptomatic.

CONCLUSION

Cardiac cement embolization following percutaneous techniques represents a life-threatening situation that should be ruled out if the patient presents symptoms during the early postoperative period. Treatment may vary from conservative to emergency open-heart surgery.

Compensatory mechanisms recruited against proximal junctional kyphosis by patients instrumented from the thoracolumbar junction to the iliac

PURPOSE

The compensatory mechanisms recruited by un-instrumented patients against sagittal imbalance are well documented. However, there is a lack of information regarding instrumented patients.

MATERIAL AND METHODS

We performed a retrospective analysis of data collected prospectively in a multicenter adult spinal deformity database. We included patients suffering PJK/PJF after (T8-L2) to iliac instrumentation with minimum two-year follow-up. We measured quantitative sagittal spinopelvic and qualitative sagittal distribution parameters in the immediate postoperative period (6w) and at the time of PJK/PJF appearance. We analyzed how these parameters changed comparing these two time points with univariate and multivariate logistic regression analyses.

RESULTS

A total of 69 patients were included. Two different patterns at PJK/PJF were found: 36 patients activated compensation (defined as an increase in pelvic retroversion (ΔRPV > 5º), and 33 did not (ΔRPV < 5º). The difference in behavior relied mostly on the amount of not surgically restored pelvic rotation at 6w (OR: 0.6; CI95%: 0.4-9.2; P = 0.017). Non-compensators had less rotation reserve (PTx100/PI = 33.9% vs 47.8%;P < 0.001) associated with worse 6w relative pelvic version and lower lumbar arc restoration, worse 6w relative sagittal alignment and GAP-score, compared with compensators (P < 0.001). Compensators' response was based on pelvic retroversion, causing lower lumbar arc decrease, lumbar apex caudal migration, and upper lumbar arc posterior inclination. Despite compensation, a thoracic kyphosis increase in both upper and lower arches gradually evolved into a PJK/PJF. Non-compensators did not react to PJK/PJF, which forced them into kyphosis from the lumbar apex and extending cranially, mainly throughout the upper thoracic arc.

CONCLUSIONS

In patients fused from the TL junction to the iliac, those having greater postoperative pelvic rotation reserve showed greater capacity to recruit compensatory mechanisms against PJK/PJF.

Ideal sagittal profile restoration and ideal lumbar apex positioning play an important role in postoperative mechanical complications after a lumbar PSO

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

To determine the influence of postoperative ideal lordosis distribution and ideal sagittal harmony on mechanical complications in patients undergoing one-level lumbar pedicle subtraction osteotomy (L-PSO). Many variables have been associated with mechanical complications after L-PSO. However, the impact of restoring the ideal inflexion point, lumbar apex, and sagittal shape is still underexplored.

METHODS

Analyzed risk factors were: age and patient-related variables, PSO level, interbody cages, rod material/diameter, number of rods, upper instrumented vertebra, lower instrumented vertebra, PI-LL mismatch, global tilt (GT), postoperative level of lumbar apex (LApex), postoperative level of inflexion point (InfxP), and postoperative type of Roussouly sagittal profile (R-type). These last variables were compared to ideal (based on pelvic incidence). Univariate and multivariate analyses were performed to identify risks for mechanical complications with a minimum 2-year follow-up.

RESULTS

A total of 87 patients were included. Mean follow-up was 4.5 ± 1.7 years. 40.2% of the patients suffered postoperative mechanical complications (7 PJK, 4 PJF, 18 pseudoarthrosis/rod breakage, 6 screw pullout). Mean time for complications was 584 ± 416 days from surgery. Univariate analysis showed that age (63 vs 57 years; P = 0.04), BMI (28.1 vs 25.9; P = 0.024), preoperative-GT (50.7° vs 38.7°; P < 0.001), postoperative-GT (28.9° vs 23.4°; P = 0.018), postoperative LApex location mismatched from ideal (77.8% vs 22.2%; P = 0.036), and postoperative R-type mismatched from ideal (67.6% vs 22.6%; P < 0.001) were significantly related to mechanical complications. The independent factors selected by multivariate analysis were: postoperative R-type mismatched from ideal OR 11.3 (95% CI   3.9-32.6; P < 0.001), age OR 1.05 (95% CI 1-1.1; P = 0.03), and LApex matching OR 0.5 (95% CI 0.27-0.97; P = 0.04). The further the LApex was from its ideal position, the higher the risk of mechanical complications (P = 0.036).

CONCLUSIONS

Over other multiple suspected risk factors, proper lumbar apex position and ideal sagittal shape restoration played an important role in postoperative mechanical complications after L-PSO.

LEVEL OF EVIDENCE

III.

Surgical Treatment of Scoliosis Developed After Extended Chest Wall Resection Due to Askin Tumor During Childhood

STUDY DESIGN

Report of four cases.

OBJECTIVE

To describe a series of pediatric patients with surgical scoliosis after chest wall resections due to Askin tumors.

SUMMARY OF BACKGROUND DATA

Askin tumors are a rare type of chest wall solid tumors that can develop in children. Treatment involves chemotherapy and extensive surgical resection, including disarticulation of several ribs. This can cause thoracogenic scoliosis, with very scarce data found in the literature regarding its treatment and prognosis.

MATERIALS AND METHODS

Retrospective descriptive series of four cases of scoliosis in pediatric patients, secondary to extensive chest resections due to Akin's tumors. We analyzed the results of the surgical treatment.

RESULTS

Three girls and one boy with a mean age of 8.7 ± 2.2 years and 7 ± 3.6 years of follow-up were included. In all cases, the convexity of the thoracic curvature was toward the area of chest resection, occurring a mean of 1.9±1.3 years after thoracic surgery. A distraction-based system (two vertically expandable prosthetic titanium rib [VEPTR], two traditional growing rods) was used to correct the scoliosis. The preoperative Cobb angle (68.7° ± 22.9°) was corrected to 32.6° ± 9.7° at final follow-up. Preoperative coronal imbalance was 2.95 ± 1.86 cm and was corrected to 0.3 ± 0.6 cm at final follow-up. No changes were observed regarding preoperative kyphosis 30° ± 8.7° (33°±8° final). T1-S1 initial length was 29.65 cm changing to 40.65 cm. T1-T12 height went from 18.25 to 23.67 cm. There was one complication secondary to the proximal anchoring.

CONCLUSIONS

For treatment of scoliosis secondary to extensive chest resection in the growing children with Askin tumors, distraction-based growth-friendly treatment is an available surgical option. Seven years of follow-up showed more than 50% improvement of the Cobb angle, and an average thoracic and trunk growth of 5.42 and 11 cm, respectively.

LEVEL OF EVIDENCE

Level IV.

[Severe idiopathic scoliosis. Does the approach and the instruments used modify the results?]

OBJECTIVE

The aim of this work is to evaluate and compare the radiographic results and complications of the surgical treatment of adolescents with idiopathic scoliosis greater than 75 degrees, using a double approach (DA) or an isolated posterior approach with hybrid instruments (posterior hybrid [PH]), or with «all-pedicle screws» (posterior screws [PS]).

MATERIAL AND METHOD

A retrospective review was performed on 69 patients with idiopathic scoliosis greater than 75°, with a follow-up of more than 2 years, to analyze the flexibility of the curves, the correction obtained, and the complications depending on the type of surgery. The Kruskal-Wallis test for non-parametric variables was used for the statistical analysis.

RESULTS

There were no statistically significant differences between the 3 patient groups in the pre-surgical Cobb angle values (DA=89°, PH=83°, PS=83°), in the immediate post-surgical (DA=34°, PH=33°, PS=30°), nor at the end of follow-up (DA=36°, PH=36°, PS=33°) (P>.05). The percentage correction (DA=60%, PH=57%, PS=60%) was similar between groups (P>.05). The percentage of complications associated with the procedure was 20.8% in DA, 10% in PH and 20% in PS. Two patients in the PS group showed changes, with no neurological lesions, in the spinal cord monitoring, and one patient in the same group suffered a delayed and transient incomplete lesion.

DISCUSSION AND CONCLUSIONS

No significant differences were observed in the correction of severe idiopathic scoliosis between patients operated using the double or isolated posterior approach, regardless of the type of instrumentation used.

[Modulation of scoliotic spine growth in experimental animals using intelligent metal bars]

OBJECTIVE

To create an experimental structural scoliosis model in mice to evaluate the efficacy of shape-memory metals to gradually correct the deformity over time.

MATERIAL AND METHOD

Experimental scoliosis was generated in 3 week-old mice by means of a suture between the left scapula and pelvis for 8 weeks. They were then randomised into two groups: a control group, in which the suture was cut, and another, in those that also had a Nitinol straight memory-wire implant fixed to the column. Serial X-rays were performed to determine the efficacy of the Nitinol in the correction of the scoliosis. In a second time, the histological changes at apical vertical body level and the adjacent discs were evaluated pre- and post-correction.

RESULTS

A mean 81.5° kyphoscoliosis was gradually induced. In the control group, after cutting the suture, an initial reduction in the deformity was observed, but later it remained stable throughout the time (54° at two weeks). In the Nitinol group, a gradual reduction was observed in the scoliosis angle value, to a mean of 8.7° at two weeks. The curvature of the apical vertebral body and adjacent discs were partially corrected after two weeks of correcting the deformity.

CONCLUSION

This scoliosis model has demonstrated the efficacy of a straight Nitinol wire fixed to the spinal column in the gradual correction of kyphoscoliosis and in the changes in its adjacent structures.