Effects of Nuss procedure on thoracic scoliosis in patients with pectus excavatum

Outcomes of the Nuss procedure in children with pectus excavatum: 14 years of experience

BACKGROUND

We aimed to assess the effectiveness of the Nuss procedure for pectus excavatum (PE) and explore the impacts of sex and age on outcomes.

METHODS

We retrospectively reviewed 594 consecutive children ≤18 years of age who underwent the thoracoscopy-assisted Nuss technique between January 2006 and July 2019. The severity of pectus deformity was calculated according to the Haller index (HI). The classification of PE and clinical data including complications was analyzed.

RESULTS

Of the 594 patients, 456 (76.8%) were boys and 138 (23.2%) were girls. The mean age at surgery was 10.0 ± 5.0 years. The most common types of PE were 1A and 2A2 according to Park classification. Intraoperative and postoperative complication rates were 2/594 (0.3%) and 74/594 (12.5%), respectively. The most common complication was bar displacement. The bar was removed in 414 patients 3.5 ± 0.8 years later. The mean preoperative HI, postoperative HI with bar, and HI after bar removal were 4.2 ± 1.7, 2.4 ± 0.3, and 2.7 ± 0.5, respectively. Compared to the preoperative HI, both the postoperative HI with bar and HI after bar removal were significantly lower ( p < 0.001). For preschool-age children, the preoperative HI was significantly higher ( p = 0.027) and the change in HI significantly improved compared to school-age children ( p = 0.004). Boys and adolescents needed significantly more bars and stabilizers.

CONCLUSION

Surgical correction of PE using the Nuss procedure is a safe procedure and improves the HI in children of different ages, even in those younger than 6 years of age.

Clinical significance of concomitant pectus deformity and adolescent idiopathic scoliosis: systematic review with best evidence synthesis

BACKGROUND

A misbalance in forces is proposed for causing adolescent idiopathic scoliosis (AIS). AIS is therefore correlated to adjacent musculoskeletal pathologies. Its concomitance with idiopathic pectus deformities (PD) is underexposed. This systematic review analyzes the clinical significance and predictive factors of PD-associated AIS.

METHODS

A search was performed in PubMed, UpToDate, Embase, and Cochrane. A study was included if it: assessed the association between PD and scoliosis (category I), reported a prevalence of scoliosis in PD patients (category II), or addressed other topics about PD-associated AIS (category III). Studies in category I discussing predictive factors were appraised using the Quality in Prognosis Studies tool. Because of heterogeneity among the studies, predictive factors were analyzed according to a best evidence synthesis. A mean prevalence of scoliosis in PD patients was calculated using category I and II. Category III was narratively reviewed.

RESULTS

Forty-eight studies were included (I:19, II:21, III:8). Category I comprised 512 patients with PD-concomitant scoliosis. Thirteen studies reported predictive factors, of which 15 concerned the prevalence of scoliosis in PD patients and 12 Cobb Angle (CA) change after PD correction. Compared with AIS, PD seems to develop earlier in adolescence, and PD with concomitant AIS was more frequently reported in older patients. Evidence remained conflicting regarding the association between the severity of PD and that of scoliosis. As opposed to at a younger age, late PD correction is not associated with a postoperative increase of CA. Limited evidence showed that patients with a high CA undergoing PD correction do not experience an increase in CA, though, strong evidence indicated that it would not lead to a decrease in CA. The mean probable prevalence of AIS in PD patients was 13.1%.

CONCLUSION

Current literature confirms the association between PD and AIS in patients with an indication for PD correction.Level of evidence: III.

[Correction of pectus excavatum and long-term outcome in adult]

Pectus excavatum is the most common congenital chest malformation characterized by symmetrical or asymmetric depression of the chest with deformation of the sternocostal complex. Pectus excavatum is often associated with other dysplastic diseases of connective tissue. Ravitch thoracoplasty and Nuss minimally invasive correction are the most common today. The authors report surgical correction of PE in a 50-years-old male who underwent Ravitch modified thoracoplasty with implantation of shape memory plate. Long-term treatment outcomes and technical properties of the plate after removing are analyzed.

A 36-Year-Old Female With Congenital Contractural Arachnodactyly and Pectus Excavatum Requiring Fourth-Time Redo Surgical Correction

Congenital contractural arachnodactyly (CCA) is a rare connective tissue disorder that has several phenotypic similarities to Marfan syndrome. Among the phenotypic characteristics of patients with CCA, severe kyphoscoliosis and thoracic cage abnormalities are commonly reported. In this case report, we describe a patient with coexisting CCA and severe pectus excavatum requiring multiple surgical repairs. The impact severe scoliosis and pectus excavatum in isolation have on cardiopulmonary anatomy and physiology can be significant, and their effects can be profound concomitantly. These defects have the propensity of causing restrictive lung disease and external cardiac compression.

The effect of minimally invasive pectus excavatum repair on thoracic scoliosis

OBJECTIVES

The Nuss technique comprises the placement of an intrathoracic bar behind the sternum. However, besides improving the body posture through the correction of the pectus excavatum (PE), this procedure may cause or worsen thoracic scoliosis as a result of the considerable stress loaded on the chest wall and the thorax. Our goal was to investigate the impact of the Nuss procedure on the thoracic spinal curvature in patients with PE.

METHODS

A total of 100 patients with PE who underwent the Nuss procedure were included in the study and evaluated retrospectively. The Haller index (HI), asymmetry index and sternal torsion angle were calculated from thoracic computed tomography images before the operation. To evaluate the scoliosis in the T2-T8 thoracic vertebrae, Cobb angles were calculated on a plain chest X-ray before the Nuss operation and after the removal of the bar. Cobb angles were classified as normal (5°), scoliotic posture (5°-10°) and scoliosis (>10°). All angles before and after the Nuss operation were compared. The patients were followed up for a mean of 41 months. Substernal bars were removed after a mean of 33 months.

RESULTS

The mean age of the patients was 19.6 ± 6.7 years. The Cobb angle was statistically significantly increased in all patients (P = 0.01), male patients (P = 0.01) and children (P = 0.046) but not in adults (P = 0.11) and female patients (P = 0.54). The Cobb angle was increased in patients with severe (HI ≥ 3.5) but not in patients with moderate (3.2 < HI < 3.5) or mild (2.0 < HI < 3.2) PE deformity.

CONCLUSIONS

The present study shows that the Cobb angle indicates that the severity of thoracic scoliosis increases following the Nuss procedure, particularly in male patients, in patients with mild and moderate sternal torsion angle and in those with a high preoperative HI. This alteration might be due to correctional forces and torque applied by the bar. Patients undergoing the Nuss procedure for the correction of PE should be followed up strictly for timely diagnosis and management of the scoliosis.

Pectus excavatum and scoliosis: a review about the patient's surgical management

Although Nuss procedure is performed with satisfactory results, there has been a controversy in the literature regarding the effect of a Nuss procedure on the spine. This review article aims to perform an updated overview of the literature about the effect of pectus excavatum correction at the spine and the management of patients with both pectus excavatum and scoliosis. Although acquired scoliosis has been rarely reported after a Nuss procedure, studies show that the Nuss procedure can have a beneficial effect in mild coexisting scoliosis especially when it is performed during the adolescence. The management of cases presented with both pectus excavatum and scoliosis depends on the severity of pre-operative scoliosis and demands detailed evaluation of the spine pre and postoperatively. In the rare condition of post-operative scoliosis following a Nuss procedure, the removal of the metallic bar and conservative measures may have satisfactory results on the spine.

TINAG mutation as a genetic cause of pectus excavatum

To investigate the possible involvement of germline mutations in pectus excavatum (PE). We investigated a four-generation pedigree with PE. Whole-exome sequencing (WES)was performed to identify potential mutations for PE formation. Sanger sequencing was used to validate these mutations. hFOB1.19 cell proliferation was measured with a Celigo imaging cytometry system. There were four PE patients in this four-generation pedigree. In the four patients, we identified a novel heterozygous stop-gain variant in Tubulointerstitial Nephritis Antigen (TINAG) through exome sequencing: c.G2A, p.W2*. This mutation was validated by Sanger sequencing. Knockdown of TINAG inhibited the proliferation of hFOB1.19 cells. Based on these results, we hypothesize that the TINAG c.G2A mutation is a loss-of-functionmutationthat reduces TINAG expression. Increasing TINAG warrants further investigation as a potential novel anabolic mechanism of PE treatment.

Serum lactate dehydrogenase activity and its isoenzyme patterns in patients with pectus excavatum

Background

In previous study, we found elevated serum total lactate dehydrogenase (LDH) before correction of pectus excavatum and a decrease in total LDH after the deformity correction. In the present study, we analyzed total LDH activity and its isoenzyme patterns to investigate the causes of these laboratory findings in patients with pectus excavatum.

Methods

Between March 2014 to December 2018, 85 patients with pectus excavatum who had undergone the Nuss procedure (NP) and bar removal (BR) were included into this study. We analyzed (I) total LDH and its isoenzyme patterns before the correction, (II) relationships of total LDH and its isoenzymes with age at time of NP, sex, severity of pectus excavatum, and pectus morphology types, and (III) post-corrective changes.

Results

The mean age of the patients was 13.6 (±6.5) years at the age of NP and the mean interval between NP and BR was 2.2 (±0.42) years. Seventy-one males and 14 females were included. The pectus types included 54 symmetric and 31 asymmetric cases. The mean Haller index before NP and BR were 3.8±1.45 and 2.7±0.4, respectively. The mean of total LDH before NP (pre-correction) and BR (post-correction) were 404.2±80.8 and 369.2±79.3 IU/L, respectively. Before correction, total LDH was significantly higher than normal values, irrespective of age [the young group (<10 years old), P=0.006, and the old group (≥10 years old), P<0.001]. The proportion of LDH5 was significantly higher than that of LDH4 (P<0.001). Total serum LDH was significantly associated with age at time of NP and Haller index (P<0.001 and P=0.030). There was no significant correlation between severity and total LDH. However, the value of only LDH5 among all isoenzymes had a significant positive correlation with severity (P=0.006) and the proportion of only LDH5 in the severe group was significantly higher (P=0.003). After correction, proportions of each isoenzyme were all within the reference range, however, there were significant decreases in values of LDH1-LDH4, except LDH5 (P=0.020, P<0.001, P<0.001, and P=0.029).

Conclusions

This study shows that pectus excavatum is a muscular disease entity and that laboratory findings are associated with compression of internal organs, which was explained by post-corrective changes in LDH activity and its isoenzyme patterns. This study will provide a deeper and wider comprehension of pectus excavatum.

Scoliosis Progression After the Nuss Procedure for Pectus Excavatum: A Case Report

INTRODUCTION

Pectus excavatum and scoliosis are associated conditions with a high rate of coincidence. However, there are no reports to guide surgeons on the management of adolescents with moderate scoliosis and pectus excavatum, because there are conflicting conclusions in the literature regarding how the Nuss procedure with substernal bar affects scoliosis.

CASES

In 2017, we encountered two patients with moderate scoliosis treated with a spinal orthosis. After undergoing the Nuss procedure for pectus excavatum, their scoliosis acutely progressed into surgical magnitude requiring posterior instrumented spinal fusion. The first patient progressed 26° despite the pre-Nuss radiographs showing him to be Risser 4/5, while the second patient also progressed 26° from the Nuss procedure. Both patients acknowledged noncompliance with brace wear because of discomfort after the Nuss procedure. However, their progression rate still doubles the rate of reported rapid accelerators, indicating that a significant component of curve progression is directly attributed to forces on the spine from the corrective maneuver with substernal bar.

CONCLUSION

The purpose of this case report is to describe the features of these two patients to help with clinical decision-making in patients with moderate scoliosis (curves >25°) who are contemplating the Nuss procedure for correction of pectus excavatum. We caution patients and providers that spinal deformity could worsen with surgical intervention of the pectus excavatum via the Nuss procedure and necessitate scoliosis surgery.

The Nuss procedure for repair of pectus excavatum: 20 error traps and a culture of safety

In 1998, Donald Nuss changed the way the world thought about the surgical repair of pectus excavatum. The new operation adheres to sound orthopedic fundaments, but has a significantly higher learning curve than other operations in pediatric surgery. Variations in pectus excavatum type, severity, symmetry and chest wall pliability bring challenges. This article will detail common error traps and ways to avoid them when performing the Nuss procedure. As recent publications have shown, an operation done more than 50,000 times across the world may bring to light infrequent but devastating outcomes that may be preventable. The critical view of safety for pectus repair is discussed, as are areas where a culture of safety could optimize results on a larger scale. We will review potential opportunities to improve outcomes by identifying error traps in the preoperative, intraoperative, and postoperative care of patients undergoing the Nuss procedure.

[Experience with Wang procedure for treatment of pectus excavatum in young children]

OBJECTIVE

To review the experience with Wang procedure for treatment of pectus excavatum in young children.

METHODS

The clinical data of 21 children with a mean age of 3.3 ± 1.1 years (ranging from 1.5-6 years) undergoing Wang procedure for pectus excavatum were analyzed. A longitudinal incision (1 to 2 cm) was made in the front of the xiphoid, and two tunnels were created using steel bars beneath the muscles on two sides of the chest wall. The fibrous tissue between the diaphragm and the sternum was dissociated, and the steel wires were sutured through the deformed chest wall. After the steel bar was placed in the tunnels, the wires were pulled and fixed in the middle of the bar, and the incision was sutured.

RESULTS

All the operations were performed using 3 wires and 1 steel bar. The operation time was 25 to 51 (38.1 ± 9.6) min with an intraoperative bleeding volume of 5 to 10 (7.1±1.5) mL. The time of hospitalization of the patients ranged from 6 to 10 days (mean 8.1±1.3 days). In all the patients, the incision healed smoothly without serious pain or obvious complications. All the patients were followed up for 1 to 13 months after the operation. During the follow- up, no recess recurred and no such complications as bar displacement or transposition occurred. According to the evaluation criteria after pectus excavatum operation, 13 cases had a total score of 9, and 8 had a total score of 8. The overall effect was satisfactory, and there were no cases rated as basically satisfactory or unsatisfactory.

CONCLUSIONS

Wang procedure is a good option for treatment of pectus excavatum in young children.

Recurrence of pectus excavatum following the Nuss procedure

Background

The recurrence of pectus excavatum (PE), in other words, chest wall depression after the completion of repair, is one of the most important issues in PE. However, little about the recurrence of PE is known. The present study aimed (I) to evaluate the characteristics of chest wall depression during treatment and (II) to present the definition of recurrence of PE, investigate the risk factors for recurrence, and predict the recurrence at one year after bar removal (BR).

Methods

Consecutive 99 patients who had undergone BR for PE in a single hospital from March 2012 to June 2017 were included in the present study. Severity of PE is presented as a radiographical Haller index (RHI) in the present study. RHI is calculated by the ratio of the transverse diameter to the anteroposterior (AP) diameter at the point of the deepest chest wall depression. Patients with a ≥3.5 RHI value, which simultaneously increased to more than the value of RHI before BR, were considered as demonstrating recurrence in the present study. Follow-up data after BR were collected at subsequent time points (i.e., immediate before and after, one month, sixth months, and one year after BR). All postoperative chest wall changes were analyzed to find out the difference according to the age at the time of the Nuss procedure (NP) [<10 years old (early group; EG) vs. ≥10 years old (late group, LG)].

Results

The mean age of patients was 8.91 (±5.23) years at the age of the NP and the mean duration of bar placement was 28.4 (±5.04) months. Seventy-eight males and 21 females were included. The pectus type was 79 symmetric and 20 asymmetric cases. The mean observation period after BR was 16.47 (±3.74) months. There was a significant correlation between the Haller index using chest CT and simple radiography data (P<0.001). Irrespective of the age groups, there were a significant decrease in RHI values after the NP (both P<0.001). In addition, there were no differences in RHI values between the EG and the LG cohort before the NP and immediately after the NP (P=0.775, P=0.356, respectively). RHI values was significantly decreased in the EG (P=0.040) and increased without a significance in the LG (P=0.330) during bar placement. The chest wall depression progressed for the first six months after BR. However, the chest wall depression did not progress one year after BR. Recurrence occurred in nine cases at one year after BR (four cases in the EG and five cases in LG). The recurrence rate was higher in the LG than in the EG without a significance (P=0.479). Multivariate analysis of the recurrence revealed that only RHI after the NP was identified as an independent risk factor of the recurrence. ROC study also showed that RHI value after the NP had a significant predictable cutoff value for the recurrence [cutoff value of RHI: 2.91, sensitivity: 88.9%, specificity: 90.0%, P<0.001, area: 0.899, 95% confidence interval (CI): 0.806-0.993].

Conclusions

The present study shows the characteristics of chest wall depression and the risk factor of the recurrence of PE after BR. The effect of the NP is different according to the patient age at the time of the procedure. Early correction of PE can provide better corrective results because of the existence of a more pliable chest wall, which can be easily and sufficiently elevated by the NP. Sufficient elevation of the depressed chest wall should be ensured during the NP to prevent the recurrence of PE.

The physiologic impact of pectus excavatum repair

The adverse physiologic effects of pectus excavatum and subsequent resolution following correction have been a subject of controversy. There are numerous accounts of patients reporting subjective improvement in exercise tolerance after surgery, but studies showing clear and consistent objective data to corroborate this phenomenon physiologically have been elusive. This is partially due to a lack of consistent study methodologies but even more so due to a mere paucity of data. As experts in the repair of pectus excavatum, it is not uncommon for pediatric surgeons to operate on adult patients. For this reason, this review evaluates the contemporary literature to provide an understanding of the physiologic impact of repairing pectus excavatum on pediatric and adult patients separately.