Can absorbable stabilizers be used routinely in the Nuss procedure?

Determining the Optimal Technique for Bar Fixation in the Repair of Pectus Excavatum

Introduction: Pectus bar stabilizers are routinely used for bar fixation in the repair of pectus excavatum. We aimed to determine the optimum technique for bar fixation by reviewing our institutional experience with the use of bilateral, unilateral, and no stabilizer placement. Methods: Retrospective single pediatric center review of patients who underwent minimally invasive bar placement for pectus excavatum and subsequent bar removal between December 2001 and July 2019 was performed. Demographic data, details about the surgery, the number of bars and stabilizers used, and follow-up information were collected. Stabilizer-related complications included pain requiring stabilizer removal, surgical site infections (SSIs), and bar displacement. Data are presented as medians with interquartile ranges (IQRs) and frequencies with percentages. Results: A total of 561 patients were included. The cohort was predominantly male (83.1%, n = 466) with a median age at the time of bar placement of 15 years (IQR 12.4, 16.3) and a median Haller index of 3.8 (IQR 3.4, 4.5). Pain attributed to the stabilizer site that required removal was observed only in the bilateral stabilizer group (2.5%, n = 13). SSI related to the stabilizer site occurred in 1.8% (n = 9) of the bilateral stabilizer cases and 2.1% (n = 1) of the unilateral stabilizer cases. Bar displacement was observed in 0.6% (n = 3) of the bilateral stabilizer cases and 2 of those patients also had an SSI. There were no complications in the no stabilizer group. Conclusion: As the trend moves toward unilateral and no stabilizer use, we observe fewer cases of pain requiring stabilizer removal with no increase in bar displacements.

Pectoralis Muscle Transposition in Association with the Ravitch Procedure in the Management of Severe Pectus Excavatum

Pectus excavatum (PE) is the most common congenital chest wall deformity. PE is sometimes associated with cardiorespiratory impairment, but is often associated with psychological distress, especially for patients in their teenage years. Surgical repair of pectus deformities has been shown to improve both physical limitations and psychosocial well-being in children. The most common surgical approaches for PE treatment are the modified Ravitch technique and the minimally invasive Nuss technique. A technical modification of the Ravitch procedure, which includes bilateral mobilization and midline transposition of the pectoralis muscle flap, is presented here.

Methods

From 2010 to 2016, 12 patients were treated by a modified Ravitch procedure with bilateral mobilization and midline transposition of the pectoralis muscle flap for severe PE. Outcomes, morphological results, and complications were analyzed with respect to this new combined surgical approach.

Results

There was a statistically significant difference between pre- and postoperative values (P = 0.0025) of the Haller index at the 18-month follow-up, showing a significant morphological improvement for all treated patients. After surgery, no morbidity and mortality were noted. The mean hospital stay was 7 days, and all patients were discharged without major complications.

Conclusion

This technique significantly improved patients' postoperative morphological outcomes and significantly reduced long-term complications, such as wound dehiscence, skin thinning, and hardware exposure.

Short Nuss bar procedure

The Nuss procedure is now the preferred operation for surgical correction of pectus excavatum (PE). It is a minimally invasive technique, whereby one to three curved metal bars are inserted behind the sternum in order to push it into a normal position. The bars are left in situ for three years and then removed. This procedure significantly improves quality of life and, in most cases, also improves cardiac performance. Previously, the modified Ravitch procedure was used with resection of cartilage and the use of posterior support. This article details the new modified Nuss procedure, which requires the use of shorter bars than specified by the original technique. This technique facilitates the operation as the bar may be guided manually through the chest wall and no additional stabilizing sutures are necessary.

Single centre experience on short bar technique for pectus excavatum

BACKGROUND

Pectus excavatum (PE) is the most frequent anomaly of the anterior chest wall. Before 2001, all patients in Denmark were referred to the plastic and reconstructive surgeon for implantation of a subcutaneous silicone prosthesis, because the modified Ravitch procedure was not used. Since 2001, all patients have been treated with a modified Nuss procedure, which today has become the gold standard for correction of PE.

METHODS

From September 2001 to March 2016, 1,713 patients have been operated by a modified Nuss procedure using the short bar at Aarhus University Hospital with a male-female ratio 6:1. The median age was 16 years (range 7-58 years). All operations were done in general anesthesia with epidural analgesia and all patients were operated by the same surgeon. All patients were seen routinely 6 weeks after surgery and the bars were removed after 3 years.

RESULTS

Patients were younger than 18 years in 1,109 cases (65%). The number of bars needed for optimal correction was one in 1,209 patients, two in 486 patients and three in 18 patients. The median length of bar changed from 11 inches to 10 inches during the study period. The annual number of procedures continued to rise during the study period [833 patients during the first 10 years and 880 patients in the last 6 years, though more patients received two bars in the later period, (34%) versus (24%)] and the proportion of patients older than 30 years increased from 7.7% to 10%. The average duration of the operation was 36 minutes (range 12-270 minutes) and did not change significantly during the study period, change in operation time which was around half an hour. The median postoperative hospital stay decreased over time from 6 to 2 days. There was no mortality.

CONCLUSIONS

The modified Nuss procedure with the short bar technique is effective for the correction of PE. The results are stable with a low rate of bar malrotations, and in may most cases can be done in less than an hour in experienced hands.

Nuss bar procedure: past, present and future

Repair of pectus excavatum began at the beginning of the 20th century before endotracheal intubation was standard practice. Surgeons therefore developed techniques that corrected the deformity using an open procedure via the anterior chest wall. Initial techniques were unsatisfactory, but by the 1930s the partial rib resection and sternal osteotomy technique had been developed and was used in combination with external traction post-operatively to prevent the sternum from sinking back into the chest. In 1949, Ravitch recommended complete resection of the costal cartilages and complete mobilization of the sternum without external traction, and in 1961 Adkins and Blades introduced the concept of a substernal strut for sternal support. The wide resection resulted in a very rigid anterior chest wall, and in some instances, the development of asphyxiating chondrodystrophy. The primary care physicians therefore became reluctant to refer the patients for repair. In 1987, Nuss developed a minimally invasive technique that required no cartilage or sternal resection and relied only on internal bracing by means of a sub-sternal bar, which is inserted into the chest through two lateral thoracic incisions and guided across the mediastinum with the help of thoracoscopy. After publication of the procedure in 1998, it became widely accepted and a flood of new patients suddenly started to appear, which allowed for rapid improvements and modifications of the technique. New instruments were developed specifically for the procedure, complications were recognized, and the steps taken to prevent them included the development of a stabilizer and the use of pericostal sutures to prevent bar displacement. Various options were developed for sternal elevation prior to mediastinal dissection to prevent injury to the mediastinal structures, allergy testing was implemented, and pain management improved. The increased number of patients coming for repair permitted studies of cardiopulmonary function, which showed that patients with a severe degree of pectus excavatum have right- sided cardiac compression, decreased filling, and decreased stroke volume. The degree of pulmonary restriction and obstruction is related to the degree of deformity and degree of cardiac displacement into the left chest. The indications for surgical repair have been clearly outlined, the procedure has been standardized, and post-operative management protocols are now available. A review of our prospective database showed that 98% of patients have a good to excellent outcome. This review of the "Past" outlines the progression of the surgical techniques during the 20th century, the review of the "Present" outlines the important modifications and results of the closed technique, and the review of the "Future" outlines the various new options that are becoming available for the treatment of pectus excavatum.

Metal/polymer composite Nuss bar for minimally invasive bar removal after Pectus Excavatum treatment: FEM simulations

This study aims at assessing the mechanical behavior of a composite metal/polymer bar to be implanted in the retrosternal position, in order to correct chest wall deformities, such as Pectus Excavatum. A 300-mm-long, 12.7-mm-wide, and 3.5-mm-thick Nuss bar was considered, made of different metals and biodegradable polymers, fixed at its extremities, and with a constant force of 250 N applied on its center. Two different geometries for the metal elements to be embedded in the polymeric matrix were tested: in the former, thin metal sheets and in the latter, cylindrical metal reinforcing rods were considered. Finite element method simulation results are reported, in terms of maximum stress and strain of the bar. Furthermore, the maximum stress values obtained by varying metal sheet thickness or rod diameter (and therefore the volumetric percentage of metal within the matrix) for different material combinations are also shown; optimal configuration for the Pectus Excavatum treatment was finally identified for a composite Nuss bar.

Pectus excavatum: history, hypotheses and treatment options

Pectus excavatum and pectus carinatum represent the most frequent chest wall deformations. However, the pathogenesis is still poorly understood and research results remain inconsistent. To focus on the recent state of knowledge, we summarize and critically discuss the pathological concepts based on the history of these entities, beginning with the first description in the sixteenth century. Based on the early clinical descriptions, we review and discuss the different pathogenetic hypotheses. To open new perspectives for the potential pathomechanisms, the embryonic and foetal development of the ribs and the sternum is highlighted following the understanding that the origin of these deformities is given by the disruption in the maturation of the parasternal region. In the second, different therapeutical techniques are highlighted and based on the pathogenetic hypotheses and the embryological knowledge potential new biomaterial-based perspectives with interesting insights for tissue engineering-based treatment options are presented.

Thirty years' experience of open-repair surgery for pectus excavatum: development of a metal-free procedure

OBJECTIVE

Throughout the history of surgery for pectus excavatum (PE), the Nuss procedure and open repair have been performed with many modifications, with most of these procedures using a metal bar. However, the use of a metal bar has several drawbacks. Thus, we aimed to develop a procedure that did not require a metal bar.

METHODS

Through our experience of 426 pediatric cases that underwent various procedures for open repair of PE at Nagoya City University, we arrived at the current procedure that we describe herein. We have evaluated this procedure by review of clinical results and deformity indices (Haller's, steepness, excavation volume, and asymmetry index).

RESULTS

The latest and current procedure that supports the sternum with a bridge constructed by the 4th or 5th costal cartilages is associated with fewer complications, a lower re-operation rate, and striking improvement in the indices examined.

CONCLUSIONS

Our current open-repair procedure that does not require a metal bar is recommended for correction of deformities of PE in children.

[Chest wall surgery]

Despite the numerous differences among the distinct diseases of the chest wall, the surgery of this area shows certain common features. Treatment has progressively changed in the last few years due to advances in diagnostic techniques, minimally invasive procedures and reconstruction materials, and especially due to the multidisciplinary management of many diseases. Nuss' minimally invasive correction of pectus excavatum has gained devotees, although open approaches are performed with increasingly small incisions, almost comparable to the lateral incisions in Nuss' technique. Surgeons supporting the open approach also cite the evident disadvantages of the need for a steel implant for 2 or 3 years and for a second intervention to remove this implant. En-bloc resections with reconstruction using materials, which are increasingly better and covered by myocutaneous grafts in collaboration with plastic surgery departments, constitute a major advance in the treatment of chest wall tumors. Trimodal therapy for Pancoast tumors, consisting of induction chemotherapy and radiotherapy and subsequent surgical treatment of the tumor, currently provides the best results in terms of resectability and survival.

Removal of pectus bar fixed with absorbable vs metallic stabilizers

BACKGROUND/PURPOSE

The removal of a pectus bar fixed with a metallic stabilizer can be time consuming and tedious, because in some cases, fibrous or new bone tissue covers the metallic devices. Our study aims to evaluate bar removal in 2 groups of patients with metallic and absorbable stabilizers, respectively.

METHODS

A total of 162 patients underwent mini-invasive repair of pectus excavatum. In all the cases, the bar was stabilized with at least 1 stabilizer on the left side. We used both metallic and absorbable stabilizers. Absorbable stabilizers were preferred when they were available in the market. The bar was removed in 30 patients. We compared removal of the bar in 17 absorbable stabilizers with those bars fixed with 18 metallic stabilizers. Length of incision, operative time, postoperative pain, and complications were studied.

RESULTS

No differences between metallic and absorbable stabilizers were found in terms of postoperative pain and complications. However, removal of the bar fixed with an absorbable stabilizer required a significantly smaller incision and shorter operative time.

CONCLUSIONS

Removal of the pectus bar fixed with an absorbable stabilizer was simpler and faster.

Stabilizing the sternum using an absorbable copolymer plate after open surgery for pectus deformities: New techniques to stabilize the anterior chest wall after open surgery for pectus excavatum

An open surgical technique for the correction of pectus deformities using an absorbable copolymer plate for the sternal stabilization is described.