Surgical treatment of scoliosis in Marfan syndrome: outcomes and complications

Integrated DNA methylation analysis reveals a potential role for PTPRN2 in Marfan syndrome scoliosis

Background

Marfan syndrome (MFS) is a rare genetic disorder caused by mutations in the Fibrillin-1 gene (FBN1) with significant clinical features in the skeletal, cardiopulmonary, and ocular systems. To gain deeper insights into the contribution of epigenetics in the variability of phenotypes observed in MFS, we undertook the first analysis of integrating DNA methylation and gene expression profiles in whole blood from MFS and healthy controls (HCs).

Methods

The Illumina 850K (EPIC) DNA methylation array was used to detect DNA methylation changes on peripheral blood samples of seven patients with MFS and five HCs. Associations between methylation levels and clinical features of MFS were analyzed. Subsequently, we conducted an integrated analysis of the outcomes of the transcriptome data to analyze the correlation between differentially methylated positions (DMPs) and differentially expressed genes (DEGs) and explore the potential role of methylation-regulated DEGs (MeDEGs) in MFS scoliosis. The weighted gene co-expression network analysis was used to find gene modules with the highest correlation coefficient with target MeDEGs to annotate their functions in MFS.

Results

Our study identified 1253 DMPs annotated to 236 genes that were primarily associated with scoliosis, cardiomyopathy, and vital capacity. These conditions are typically associated with reduced lifespan in untreated MFS. We calculated correlations between DMPs and clinical features, such as cobb angle to evaluate scoliosis and FEV1% to assess pulmonary function. Notably, cg20223687 (PTPRN2) exhibited a positive correlation with cobb angle of scoliosis, potentially playing a role in ERKs inactivation.

Conclusions

Taken together, our systems-level approach sheds light on the contribution of epigenetics to MFS and offers a plausible explanation for the complex phenotypes that are linked to reduced lifespan in untreated MFS patients.

Impact of pathogenic FBN1 variant types on the development of severe scoliosis in patients with Marfan syndrome

BACKGROUND

Among the several musculoskeletal manifestations in patients with Marfan syndrome, spinal deformity causes pain and respiratory impairment and is a great hindrance to patients' daily activities. The present study elucidates the genetic risk factors for the development of severe scoliosis in patients with Marfan syndrome.

METHODS

We retrospectively evaluated 278 patients with pathogenic or likely pathogenic FBN1 variants. The patients were divided into those with (n=57) or without (n=221) severe scoliosis. Severe scoliosis was defined as (1) patients undergoing surgery before 50 years of age or (2) patients with a Cobb angle exceeding 50° before 50 years of age. The variants were classified as protein-truncating variants (PTVs), which included variants creating premature termination codons and inframe exon-skipping, or non-PTVs, based on their location and predicted amino acid alterations, and the effect of the FBN1 genotype on the development of severe scoliosis was examined. The impact of location of FBN1 variants on the development of severe scoliosis was also investigated.

RESULTS

Univariate and multivariate analyses revealed that female sex, PTVs of FBN1 and variants in the neonatal region (exons 25-33) were all independent significant predictive factors for the development of severe scoliosis. Furthermore, these factors were identified as predictors of progression of existing scoliosis into severe state.

CONCLUSIONS

We elucidated the genetic risk factors for the development of severe scoliosis in patients with Marfan syndrome. Patients harbouring pathogenic FBN1 variants with these genetic risk factors should be monitored carefully for scoliosis progression.

Surgical outcome of scoliosis in patients with Marfan syndrome

PURPOSE

To evaluate clinical and radiographic outcomes after surgical scoliosis correction and posterior instrumented fusion in SMF patients.

METHODS

A single-center medical database was reviewed to identify MF patients who presented with scoliosis from 2000 to 2015. Patients who underwent spinal fusion surgery were included. Demographic, operative and clinical data were reviewed, and the preoperative, postoperative, and latest follow-up radiographic parameters were compared.

RESULTS

Twelve patients were identified (2 males, 10 females) with an average age at surgery of 14.4 ± 2.6 years. Comorbidities were found in 84.6%. Most patients (90.9%) presented with a right thoracic curve. The average preoperative Cobb angle was 75.6 ± 15.5 degrees. Posterior instrumented spinal fusion was performed in all patients (1 hook/pedicular screw and 11 pedicle screws only). The average follow-up period was 6.8 ± 3.1 years. The mean postoperative Cobb angle after surgery and at the final follow-up was 33.4 ± 18.0 degrees and 35.5 ± 18.4 degrees, respectively. There was a statistically significant difference among the preoperative and postoperative Cobb angles (p < 0.001), but no significant difference among the sagittal angles. Two perioperative complications including superficial wound infection and broken rods were observed.

CONCLUSIONS

Posterior scoliosis correction and instrumented spinal fusion resulted in a satisfactory outcome in MF patients. Perioperative complications are not uncommon; however, no neurological complication or spinal decompensation was observed in this study.

LEVEL OF EVIDENCE

IV.

Intraoperative hypotension during surgical treatment for Marfan syndrome scoliosis in children

PURPOSE

To explore the occurrence and risk factors of intraoperative hypotension during children's Marfan syndrome scoliosis surgery and summarize the associated hemodynamic features and handle measures.

METHODS

Twenty-two Marfan syndrome scoliosis patients who underwent spinal surgery at Beijing Children's Hospital were retrospectively reviewed between January 2001 and January 2020. Intraoperative hypotension is defined as the minimum mean arterial pressure ≤ 60 mm Hg. The patients were divided into the hypotension group and the control group. Clinical, radiographic, and operative data were compared between the two groups. The risk factors, hemodynamic features, and handle measures for intraoperative hypotension in Marfan syndrome scoliosis surgery were analyzed and summarized.

RESULTS

Twenty-two patients were included in the study, with a mean age of 11.4 years at initial surgery. The follow-up period ranged from 24 to 152 months. Intraoperative hypotension occurred in 14 cases, with an incidence of 63.6%. The proportion of pulmonary dysfunction in the hypotension group was higher than in the control group (100.0% vs 50.0%, p < 0.05). The spinal flexibility was significantly lower in the hypotension group (28.3% ± 14.2% vs 46.5% ± 11.5%, p < 0.05). Fourteen patients with intraoperative hypotension had decreased intraoperative systolic blood pressure 21.0%-50.0% compared with baseline. One patient had a transient decrease in the muscle strength of the lower limbs. No complications were observed during the follow-up.

CONCLUSION

The incidence of intraoperative hypotension in Marfan syndrome scoliosis children who underwent surgery was 63.6%. The risk factors included preoperative pulmonary dysfunction and poor spinal flexibility. Comprehensive preoperative evaluation and effective hemodynamic handling measures should be undertaken to prevent further complications in children with Marfan syndrome scoliosis.

Tranexamic acid use is associated with reduced intraoperative blood loss during spine surgery for Marfan syndrome

PURPOSE

The utility of tranexamic acid (TXA) in patients with Marfan syndrome (MFS) is uncertain given associated aberrations within the vasculature and clotting cascade. Therefore, this study aimed to assess the association of TXA use with intraoperative blood loss and allogeneic blood transfusions in patients with MFS who underwent spinal arthrodesis.

METHODS

We queried our institutional database for MFS patients who underwent spinal arthrodesis for scoliosis between 2000 and 2020 by one surgeon. We excluded procedures spanning < 4 vertebral levels, those using anterior or combined anterior/posterior approaches, and those involving growing rods, postoperative infection, or spondylolisthesis. Fifty-two patients met our criteria, of whom 22 were treated with TXA and 30 were not. Mean differences in blood loss, transfusion volume, and proportions receiving transfusion were compared between TXA and the control groups using Student t, chi-squared, or Fisher exact tests. Alpha = 0.05.

RESULTS

MFS patients treated with TXA experienced less mean (± standard deviation) intraoperative blood loss (1023 ± 534 mL) compared to the control group (1436 ± 1022 mL) (p = 0.01). The TXA group had estimated blood volume loss of 27% ± 16% compared to 36% ± 21% for controls (p = 0.05). No differences were found in allogeneic transfusion rate (p = 0.66) or transfusion volume (p = 0.15).

CONCLUSIONS

We found an association between TXA use and reduced blood loss during surgical treatment of MFS-associated scoliosis, suggesting that the connective tissue deficiency in MFS does not interfere with TXA's mechanism of action.

LEVEL OF EVIDENCE

III.

The Musculoskeletal Manifestations of Marfan Syndrome: Diagnosis, Impact, and Management

Purpose of Review

Marfan syndrome (MFS) is an autosomal dominant heritable disorder of fibrillin-1 (FBN1) with predominantly ocular, cardiovascular, and musculoskeletal manifestations that has a population prevalence of approximately 1 in 5–10,000 (Chiu et al. Mayo Clin Proc. 89(1):34–42, 146, Dietz 3, Loeys et al. J Med Genet. 47(7):476–85, 4).

Recent Findings

The vascular complications of MFS still pose the greatest threat, but effective management options, such as regular cardiac monitoring and elective surgical intervention, have reduced the risk of life-threatening cardiovascular events, such as aortic dissection. Although cardiovascular morbidity and mortality remains high, these improvements in cardiovascular management have extended the life expectancy of those with MFS by perhaps 30–50 years from an estimated mean of 32 years in 1972 (Dietz 3, Gott et al. Eur J Cardio-thoracic Surg. 10(3):149–58, 147, Murdoch et al. N Engl J Med. 286(15):804–8, 148). The musculoskeletal manifestations of MFS, which to date have received less attention, can also have a significant impact on the quality of life and are likely to become more important as the age of the Marfan syndrome population increases (Hasan et al. Int J Clin Pract. 61(8):1308–1320, 127). In addition, musculoskeletal manifestations are often critically important in the diagnosis of MFS.

Summary

Here, we review the main clinically relevant and diagnostically useful musculoskeletal features of MFS, which together contribute to the “systemic features score” (referred to hereafter as systemic score), part of the revised Ghent nosology for MFS. We discuss current treatment strategies and highlight the need for a multidisciplinary approach to diagnosis and management. Finally, we review new pharmacological approaches that may be disease modifying and could help to improve the outcome for individuals with this syndrome.

Predictive Physical Manifestations for Progression of Scoliosis in Marfan Syndrome

STUDY DESIGN

A retrospective study of the prospective cohort.

OBJECTIVE

To demonstrate the accurate distribution of the severity of scoliosis in patients with Marfan syndrome, and to identify the predictive physical features for progression of scoliosis in Marfan syndrome.

SUMMARY OF BACKGROUND DATA

To date, no study has unveiled the risk factors for the progression of scoliosis in Marfan syndrome.

METHODS

We retrospectively obtained data from a prospective cohort of the Marfan syndrome clinic at our institute. We enrolled patients whose whole spine radiographs in the standing position were evaluated at the age of 15 or above, from January 2014 to March 2020. The collected variables were physical manifestations defined as in the systemic score of the revised Ghent nosology. We classified the degree of scoliosis into four categories: "not apparent," "mild" (10° ≤ Cobb < 25°), "moderate" (25° ≤ Cobb < 40°), and "severe" (40° ≤ Cobb or surgery conducted). To identify the risk factors for progression of scoliosis in Marfan syndrome, we conducted univariate and multivariate association analyses between severe scoliosis and each physical manifestation.

RESULTS

We identified 131 eligible patients (61 men and 70 women) with a mean age of 31.2 years. Scoliosis with a Cobb angle of ≥10° was identified in 116 patients (88.5%). Moderate scoliosis was identified in 33 patients (25.2%) and severe scoliosis in 53 patients (40.5%). The prevalence of each physical manifestation was equivalent to that reported in previous studies. Multivariate logistic regression analysis revealed that female sex (odds ratio, 3.27) and positive wrist sign (4.45) were predictive factors for progression of scoliosis into severe state in patients with Marfan syndrome.

CONCLUSIONS

The present study demonstrated the accurate distribution of the severity of scoliosis and identified the predictive factors for progression of scoliosis in patients with Marfan syndrome.Level of Evidence: 3.

Growth-friendly Spinal Instrumentation in Marfan Syndrome Achieves Sustained Gains in Thoracic Height Amidst High Rates of Implant Failure

BACKGROUND

There are few reports on the surgical management of early-onset scoliosis (EOS) associated with Marfan syndrome (MFS). Affected patients tend to have more rapid curve progression than those with idiopathic EOS, and their course is further complicated by medical comorbidities. As surgical techniques and implants for growing spines become more widely applied, this study seeks to better delineate the safety and efficacy of growth-friendly spinal instrumentation in treating this population.

METHODS

A prospective registry of children treated for EOS was queried for MFS patients treated between 1996 and 2016. Forty-two patients underwent rib-based or spine-based growing instrumentation and were assessed on preoperative, surgical, and postoperative clinical and radiographic parameters including complications and reoperations. Subgroup analysis was performed based on spine-based versus rib-based fixation.

RESULTS

Patients underwent their index surgery at a mean age of 5.5 years, when the major coronal curve and kyphosis measured 77 and 50 degrees, respectively. Over half were treated with traditional growing rods. Patients underwent 7.2 total surgical procedures-4.7 lengthening and 1.9 revision surgeries not including conversion to fusion-over a follow-up of 6.5 (±4.1) years. Radiographic correction was greatest at index surgery but maintained over time, with a final thoracic height measuring 23.8 cm. Patients experienced a mean of 2.6 complications over the course of the study period; however, a small group of 6 patients experienced ≥6 complications while over half of patients experienced 0 or 1. Implant failures represented 42% of all complications with infection and pulmonary complications following.

CONCLUSIONS

This is the largest report on patients with EOS and MFS. All subtypes of growth-friendly constructs reduced curve progression in this cohort, but complications and reoperations were nearly universal; patients were particularly plagued by implant failure and migration. Further collaborations are needed to enhance understanding of optimal timing and fixation constructs for those with MFS and other connective tissue diseases.

Migration of a Lumbar Spinal Fusion Rod Into the Posterolateral Knee: A Case Report

STUDY DESIGN

Case report (level V evidence).

OBJECTIVE

We report a case of a 33-year-old man with Marfan syndrome that visited our clinic for left knee pain and stiffness. Radiographs of the left knee and lumbar spine demonstrated a spinal rod in the posterolateral left knee and its origin being a broken rod from his previous unilateral spinal fusion 17 years prior.

SUMMARY OF BACKGROUND DATA

Spinal arthrodesis is a common treatment modality for a wide range of spinal pathologies including infection, trauma, congenital and developmental deformities, and degenerative conditions. A rare complication that may arise from said procedure is implant migration, most often a result of pseudoarthrosis.

METHODS

Description of the case report.

RESULTS

Patient was taken to the operating room 2 weeks later for an uneventful removal of the implant and immediate improvement with pain and range of motion.

CONCLUSION

Spinal implant migration is a rare complication most often due to implant failure from pseudoarthrosis. In the case presented, this phenomenon was likely attributed to the use of unilateral instrumentation coupled with Marfan syndrome, shown to lead to insufficient implant stability and poorer fusion rates, respectively.Level of Evidence: 5.

A scoping review presenting a wide variety of research on paediatric and adolescent patients with Marfan syndrome

Aim

The present study aimed to map and summarise the research on children, aged 0‐18 years, with Marfan syndrome, identify research gaps and point to research agendas.

Methods

A scoping review was systematically performed by searching multiple databases from January 1996 to April 2019. Primary studies presenting results on at least six individuals aged 0‐18 years with Marfan syndrome, diagnosed according to the Ghent nosology, were selected.

Results

From 2341 de‐duplicated records, 92 papers were included, mapped and described. Their topics were diagnostics (12%), cardiovascular matters (50%), skeletal matters (22%), ocular matters (9%), other medical aspects (5%) and psychosocial perspectives (2%). Most studies were from Europe and North America and published between 1999 and 2019 in subject‐specific or paediatric journals, while a few were published in genetics journals. All studies had quantitative designs, and very few were multicentre studies. Each study had six to 608 subjects for a total of approximately 5809.

Conclusion

A wide range of research topics on adolescent and paediatric Marfan syndrome was found, but qualitative studies and a focus on psychosocial matters were lacking. Future investigations addressing noncardiovascular consequences and patient experiences are needed, as well as studies reaffirming or replicating existing intervention study results.

Sublaminar fixation versus hooks and pedicle screws in scoliosis surgery for Marfan syndrome

Background:

In patients with Marfan syndrome (MFS), surgical correction of spinal deformities with hooks and/or pedicle screws involves a higher rate of complications than in patients with adolescent idiopathic scoliosis. Therefore, sublaminar instrumentation is often a last resort option. This study wants to assess the ability of sublaminar fixation to achieve three-dimensional scoliosis correction and spine stabilization compared with hook and/or pedicle screw systems.

Methods:

Twenty-one MFS patients who underwent posterior spinal fusion at a highly specialized medical center in 1995–2017 were divided into two different groups retrospectively evaluated at a minimum follow-up of 2 years. Group 1 (8 patients) was composed by hooks and screws instrumentation, while Group 2 (13 patients) was composed by hook or pedicle screw system associated to sublaminar wires/bands. Radiological (correction and long-term stability) and general endpoints (mean blood loss, surgery time, and complications) were compared between the groups.

Results:

The degree of correction compared with the preoperative status was satisfactory with both approaches, although the difference between them was not significant. No significant differences were found for general endpoints between groups.

Conclusion:

Our data suggest that scoliosis correction with sublaminar fixation is not inferior to treatment with hooks and/or pedicle screws.

Level of Evidence:

III.

Morphological Differences Between the Pedicles in Nondystrophic Scoliosis Secondary to Neurofibromatosis Type 1 and Those in Adolescent Idiopathic Scoliosis

OBJECTIVE

To compare the pedicle morphology of nondystrophic scoliosis secondary to neurofibromatosis type 1 (ND-NF1) scoliosis secondary to neurofibromatosis type 1 (NF1-S) and adolescent idiopathic scoliosis (AIS) using computed tomography (CT) in a consistent classification system.

METHODS

The transverse pedicle widths of cancellous and cortical channels were measured using preoperative spinal CT images (T1-L5) and then classified as having type A-E pedicles; type B, C, D, and E pedicles were regarded as abnormal. A subset of these patients, a postoperative CT was performed to evaluate the accuracy of pedicle screw placement. According to the perforation of the medial or lateral pedicle walls by the pedicle screw, the placement of screw was classified by a grade ranging from 0 to 3, and grades 2 and 3 were regarded as misplacement.

RESULTS

In total, 3230 pedicles were measured and classified, and the incidence rate of abnormal pedicles in the ND-NF1 group was significantly greater than that of the AIS group (65.9% vs. 61.4%, P = 0.03). The misplacement rate in the ND-NF1 group was significantly greater than that in the AIS group (12.2% vs. 7.4%; P = 0.01), and in terms of the corresponding 1100 pedicles, the incidence rate of abnormal pedicles in the ND-NF1 group was higher than that in the AIS group (71.7% vs. 64.9%; P = 0.02).

CONCLUSIONS

The incidence rate of abnormal pedicles in patients with ND-NF1 is significantly greater than that of patients with AIS, and it may the reason for the higher misplacement rate of pedicle screws in patients with ND-NF1.

Increased visceral arterial tortuosity in Marfan syndrome

BACKGROUND

Clinical evidence suggests that the currently recommended approach to estimate the risk of aortic dissection in Marfan syndrome (MFS) is not reliable enough. Therefore, we investigated the possible role of visceral arterial tortuosity in the risk stratification.

METHODS AND RESULTS

Splenic and renal arteries of 37 MFS patients and 74 age and gender matched control subjects were segmented using CT angiography imaging. To measure tortuosity, distance metric (DM), sum of angles metric (SOAM), inflection count metric (ICM), and the ratio of ICM and SOAM (ICM/SOAM) were calculated. DM of the splenic, right and left renal artery was significantly higher in MFS patients than in controls (2.44 [1.92-2.80] vs. 1.75 [1.57-2.18] p < 0.001; 1.16 [1.10-1.28] vs. 1.11 [1.07-1.15] p = 0.011; 1.40 [1.29-1.70] vs. 1.13 [1.09-1.23] p < 0.001, respectively). A similar tendency for ICM and an opposite tendency for SOAM were observed. ICM/SOAM was significantly higher in the MFS group compared to controls in case of all three arteries (73.35 [62.26-93.63] vs. 50.91 [43.19-65.62] p < 0.001; 26.52 [20.69-30.24] vs. 19.95 [16.47-22.95] p < 0.001; 22.81 [18.64-30.96] vs. 18.38 [15.29-21.46] p < 0.001, respectively). MFS patients who underwent aortic root replacement had increased right and left renal DM and ICM/SOAM compared to MFS patients without surgery.

CONCLUSION

To our knowledge this is the first demonstration of increased arterial tortuosity in MFS on visceral arteries. Visceral arterial tortuosity, dominated by curves of lower frequency but higher amplitude according to the observed opposite tendency between the DM and SOAM metrics, could be a possible new predictor of serious manifestations of MFS.

Correction of Scoliosis with Large Thoracic Curves in Marfan Syndrome: Does the High-Density Pedicle Screw Construct Contribute to Better Surgical Outcomes

Background

The aim of this study was to determine whether higher density screw constructs resulted in better surgical outcomes in patients with scoliosis secondary to Marfan syndrome (MF-S) with large thoracic curves (≥70°).

Material/Methods

There were 34 MF-S patients who met the inclusion criteria and were evaluated radiographically before surgery, 2 weeks after operation, and at the final follow-up. The mean screw density was taken as the boundary, and patients were categorized as either in the high density (HD) group or the low density (LD) group. Parameters measured included coronal Cobb angle, T5–T12 kyphosis (TK), and T12–S1 lordosis (LL). Additionally, the operation duration, estimated blood loss, screw accuracy, complication rate, and clinical outcomes were compared between the 2 groups.

Results

The mean screw density of all patients was 1.40±0.15 (range 1.13 to 1.67). Correction rate of the thoracic curve was closely related to the screw density at the concave side (r=0.783, P=0.007). Intergroup comparison showed a significantly higher correction rate of the thoracic coronal curve in HD group (56.59±4.80% versus 44.54±9.61%, P=0.036). At last follow-up, coronal correction loss of >5° occurred in 8 cases (47.1%) in the LD group and 3 cases (17.6%) in the HD group. Both groups demonstrated improvement in each domain of the SRS-22 questionnaire after surgery and no significant intergroup difference was found.

Conclusions

The high-density pedicle screw construct contributed to the significantly improved correction rate of thoracic curves in MF-S patients with large thoracic curves (≥70°). Additionally, increasing of pedicle screw number could help to enhance the structural stability and reduce the correction loss during the follow-up period.

Trends in spinal deformity surgery in Marfan syndrome

STUDY DESIGN

Analysis of a national database.

OBJECTIVE

To analyze trends in fusion surgery for spinal deformity in Marfan syndrome (MFS) patients, compare patients with and without Marfan, and evaluate differences in surgical approaches.

SUMMARY OF BACKGROUND DATA

National trends of fusion surgery for spinal deformities in MFS patients are not known. Given the rarity of MFS and the nuanced differences in the spinal deformity it causes, it is important to explore differences in fusion surgery between spinal deformity patients with and without MFS.

METHODS

We identified 314 patients (1,410 weighted) with a diagnosis of MFS and spinal deformity who underwent spinal fusion between the years 2003 and 2014. Our primary outcome was national trends in the use of posterior (PSF), anterior-posterior (APSF), and anterior (ASF) spinal fusions. We also compared perioperative complications, mortality rate, length of stay, and hospital charges in a propensity score matched sample of spinal fusion patients with and without a diagnosis of MFS.

RESULTS

The proportion of PSF surgeries increased significantly (p<.01) from 66.7% in 2003 to 92.0% in 2014. MFS patients were more likely to have higher neurologic (2.4% vs. 0.79%, p=.01) complications. There was a significant association between age and approach (p<.01). PSF had a mean age of 20.2, whereas APSF and ASF had mean ages of 27.1 and 35.2, respectively. Approximately 62% of cervical fusions used ASF.

CONCLUSIONS

Our study provides findings from the largest sample analyzed to date and is the only thus far that investigates national trends. Our results are largely consistent with those of other works in that MFS patients undergoing spinal fusion surgery have higher neurologic complications. We also report that surgical treatment has shifted toward a posterior approach. Our findings can give surgeons a better understanding of the postoperative complications and changing national trends in spinal fusion surgery for patients with MFS.

Surgical treatment of spinal deformities in Marfan syndrome: Long-term follow-up results using different instrumentations

Background:

Scoliosis is the most frequent spinal deformity related to Marfan syndrome (MFS). Treatment with a brace is often ineffective, and surgical treatment is very challenging; many instrumentations were used along the years. Our retrospective study has the purpose of identifying the reliability of different devices in three-dimensional correction of the spine deformities in MFS.

Materials and Methods:

We reviewed retrospectively the records of patients surgically treated, in a single institution between 1999 and 2016, for spinal deformities in MFS. X-rays were reviewed for analyzing the magnitude of the curves in preoperative time (T0), the amount of correction in the immediate after surgery period (T1), and it's stability at follow-up (FU) (T2). The clinical outcomes were also evaluated with the Scoliosis Research Society 24.

Results:

A total of 21 patients with a mean age at surgery of 16 years met inclusion and exclusion criteria. Four different construct types were identified: hooks with sublaminar wires (G1), hooks and pedicle screws (G2), pedicle screws (G3), and pedicle screws with sublaminar wires (G4). The mean FU time was 8 years. The average major scoliosis curve had a mean value of 63.48° at T0 and was corrected to 28.81° at T2. Furthermore, minor curve, thoracic lordosis, and lumbar kyphosis (when associated to scoliosis) were also corrected. Student t-test showed significative differences (P < 0.05) for all curves between T0–T1 and T0–T2 while between T1 and T2, no differences were found. We also evaluated separately the results of each instrumentation, and G3 obtained the best performances.

Conclusions:

Our results shows that screws may guarantee a better correction of the deformities.

Level of Evidence:

III

Accuracy of pedicle screw placement in patients with Marfan syndrome

BACKGROUND

There is no study concerning safety and accuracy of pedicle screw placement in Marfan syndrome. The objective of this study is to investigate accuracy and safety of pedicle screw placement in scoliosis associated with Marfan syndrome.

METHODS

CT scanning was performed to analyze accuracy of pedicle screw placement. Pedicle perforations were classified as medial, lateral or anterior and categorized to four grades: ≤ 2 mm as Grade 1, 2.1-4.0 mm as Grade 2, 4.1-6.0 mm as Grade 3, ≥6.1 mm as Grade 4. Fully contained screws or with medial wall perforation ≤ 2 mm or with lateral wall perforation ≤ 6 mm and without injury of visceral organs were considered acceptable, otherwise were unacceptable.

RESULTS

976 pedicle screws were placed, 713 screws (73.1%) were fully contained within the cortical boundaries of the pedicle. 924 (94.7%) screws were considered as acceptable, and 52 (5.3%) as unacceptable. The perforation rate was higher using free-hand technique than O-arm navigation technique (30.8% VS. 11.4%, P < 0.05), higher in lumbar region than in thoracic region (34.1% VS. 22.3%, P < 0.05) and higher in concave side than in convex side (33.5% VS. 21.9%, P < 0.05). No injury of visceral organs especially aorta erosion was noted in the series. 7 cases of dural tear caused by misplaced screws occurred, and 4 cases developed cerebro-spinal fluid leak. Drainage and pressure dressings were applied for these patients, and no infection was observed. Leg pain was observed in 7 cases, and 2 cases simultaneously complained of leg weakness. Revision surgery was conducted to remove the misplaced screws for these 2 patients. Conservative treatment was applied for the 5 patients without leg weakness. Symptoms of leg weakness and pain resolved in all patients.

CONCLUSION

Placement of pedicle screw in Marfan syndrome is accuracy and safe. O-arm navigation was an effective modality to ensure the safety and accuracy of screw placement. Special attention should be paid when screws were placed at the lumber spine and the concave side of spine deformity to avoid the higher rate of complications.