Scoliosis and Pectus Excavatum in Adolescents: Does the Nuss Procedure Affect the Scoliotic Curvature?

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.

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.

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.