The search for stability: bar displacement in three series of pectus excavatum patients treated with the Nuss technique

Effect of medial stabilizer chest position on pectus bar dislocation

PURPOSE

The current standard method for pectus excavatum (PE) repair is the Nuss procedure. One major postoperative complication is the displacement of the implanted metal bar, which is used to remodel the chest wall. Blocking the possible ways that the bar can be displaced with the use of stabilizers and peri/intracostal sutures has reduced the incidence of bar displacement. Despite the modifications, bar dislocation is often reported. We adopted the medial position stabilizer placement method and imposed no postoperative restrictions. In this study, we analyzed the bar dislocation rate with this modification and concurrent postoperative full activity.

METHODS

Nuss procedure modification where stabilizers are placed bilaterally in the medial location was done on patients irrespective of age and Haller index greater than 3.25. A single bar was used for all patients. Cryoanalgesia was performed on every patient. No postoperative restrictions were imposed on the patients. Full immediate activities, including sports, were allowed.

RESULTS

114 patients (103 male, 11 female) were analyzed from 2016 to 2023. The median age was 15 years old. There was zero incidence of bar displacement. The combined incidence of other postoperative complications was 4%: 2 wound infections and 2 hematoma formations, both needing incision and drainage.

CONCLUSION

Bilateral medial stabilizer placement resulted in no incidence of bar dislocation. Return to immediate full activities after the Nuss procedure did not appear to increase the incidence of bar displacement if stabilizers were placed medially.

Biocompatible Cable Ties Are an Alternative to Metal Stabilizers for Bar Securement During Minimally Invasive Pectus Excavatum Repair

Background: Bar stabilization during minimally invasive pectus excavatum repair (MIRPE) is critical to avoid dislodgement. Multiple techniques are described including stabilizers, wires, and sutures. This retrospective study compared bar movement and outcomes between existing techniques and ZipFix™, a biocompatible cable tie. Methods: Patients ≤20 years of age who underwent MIRPE with ZipFix between January 2021 and September 2022 were compared with historical controls who underwent repair by same surgeons between January 2018 and December 2020 using stabilizers or polydioxanone suture (PDS). Demographics, clinical details, and outcomes were compared using Kruskal-Wallis and chi-square tests. Results: Of the 116 patients who underwent repair, 45 had bars secured with ZipFix (39%) and 71 (61%) were historical controls (35 stabilizer, 36 PDS). Median (interquartile range) age was 15 (14-16) years and Haller index was 3.9 (3.6-4.5). Nine (8%) patients required two bars. Haller index and use of second bar were comparable between stabilization techniques (P > .05). In total, 49 patients (40%) reported any pain at 1 month and this was similar between stabilization techniques (P = .45). Median bar movement was greater for bars secured with PDS than with ZipFix or stabilizers at 1 month (5.5 versus 2.3 versus 3.3°, P = .010) and last follow-up (6.5 versus 2.1 versus 3.6°, P < .001). One patient whose bar was secured with PDS required revision for dislodgement. Conclusion: Pectus bar stabilization with ZipFix is a safe alternative to metal stabilizers and both techniques are superior to suture stabilization alone. The use of ZipFix may be preferred given its lower cost and ease of use.

Intercostal Nerve Cryoablation for Postoperative Pain Control in Pediatric Thoracic Surgery: A Scoping Review

Background: Cryoanalgesia uses the application of cold temperatures to temporarily disrupt peripheral sensory nerve function for pain control. This review outlines the principles of cryoablation, clinical applications, and clinical data for its use in pediatric thoracic surgery. Methods: A comprehensive PubMed search was performed using the principal terms and combinations of cryoablation, cryoanalgesia, Nuss, Nuss repair, pectus, pectus excavatum, thoracic surgery, thoracotomy, and chest wall. Pediatric articles were reviewed and included if relevant. Adult articles were reviewed for supporting information as needed. Reference lists of included articles were reviewed for possible additional sources. Discussion: The scientific and clinical principles of cryoablation are outlined, followed by a focused review of current clinical application and outcome data. Conclusion: Postoperative pain is a major challenge following thoracic surgery. Cryoanalgesia is emerging as an adjunct in pediatric thoracic surgery, particularly for the Nuss procedure or minimally invasive repair of pectus excavatum. It effectively controls pain, decreasing postoperative opioid use and hospital length of stay with few short-term complications. Although more long-term studies are needed, early evidence suggests there is reliable return of sensation to the chest wall and long-term neuropathic pain is rare.

Spontaneous subdiaphragmatic bar migration after pectus excavatum treatment

A case of an adolescent boy with persistent thoracic symptoms and recurrence of pectus excavatum (after previous treatment with the Nuss procedure) is presented. During thoracoscopic revision, subdiaphragmatic migration of the implant was noted. The bar was removed without damage to the intra-abdominal organs or other complications, and a new bar was placed and stabilised. Revision showed successful correction of the thorax, and the boy had no thoracic symptoms.

Stiffness reduction of the rib cage to perform a minimally invasive pectus excavatum repair: biomechanical evaluation

OBJECTIVES

To study the influence of sternal transection and costal chondrotomies on the stiffness and stresses in the rib cage of adult patients undergoing Nuss pectus excavatum procedure.

METHODS

Four pectus excavatum models with different Haller indexes were created by parameterizing a 3D model of a rib cage obtained based on a computed tomography scan of a patient with no pectus deformity. Using the finite element method, insertion of intrathoracic bars into all models was simulated in 3 conditions, namely, non-intervened, transverse sternal section and costal chondrotomies. Stiffness, stress distribution and maximum stresses for each case were obtained and compared.

RESULTS

Transverse sternotomy provided a reduction of 44% to 54% in the stiffness of the rib cage, depending on the Haller index analysed, while chondrotomies promoted a stiffness reduction of 70%. Stress distribution in the rib cage followed similar pattern for all the tested Haller index, but the maximum stress decreased by 36% when performing a transverse sternotomy, whereas when performing costal chondrotomies, it decreased by 47%.

CONCLUSIONS

Computational results report that transverse sternotomy reduces appreciably the stiffness of the rib cage, while costal chondrotomies promote even a higher stiffness reduction. Thus, these surgical procedures could improve the clinical outcomes of adult patients undergoing a pectus excavatum repair.

Quality of life outcomes after minimally invasive repair of pectus excavatum utilizing a new set of metallic bars and stabilizers

BACKGROUND/PURPOSE

The aim of the study was to evaluate the postoperative quality of life (QoL) of patients who underwent minimally invasive repair of pectus excavatum (MIRPE) with a newly designed bar and bar stabilizers.

METHODS

We conducted a prospective randomized study in which patients were operated either with standard perpendicular stabilizers (control group) or with the newly designed oblique stabilizers (intervention group). All patients were evaluated 6 months after the operation with the Pectus Excavatum Evaluation Questionnaire (PEEQ).

RESULTS

There were 16 patients in the control group and 14 in the intervention group. Mean age was 17 (SD: 3.3, range 14-27) years. There were no demographic differences between groups. Two patients in the control group and one in the intervention group were repaired with two bars instead of one. There was one reoperation in each group. There was a significant difference between the pre- and postoperative scores, in both groups, in the patient body image domain (control group: 9.5 to 3; p < 0.01; intervention group 10 to 3; p < 0.01), as well as in the psychosocial domain (control group: 13.5 to 24, p < 0.01; intervention group: 15 to 24, p < 0.01). With regards to the patients' perception of physical difficulties before and after MIRPE, the difference between pre- and postoperative scores was greater in the intervention group (8 to 12, p < 0.01) than in the control group (10 to 11, p = 0.04). The mean length of stay was 4.5 and 5 days in the intervention group and the control group, respectively.

CONCLUSION

Our study showed that patients who underwent MIRPE with the newly designed bars and stabilizers had non-inferior outcomes than patients reported in the literature who underwent MIRPE with standard bars and stabilizers. We found slightly better outcomes in patients in the intervention group compared to the control group, but larger studies will be needed to confirm if those differences are statistically significant.

LEVEL OF EVIDENCE

II.

Single-centre Indian case series using X or cross bar for Nuss procedure in pectus excavatum

The modified Nuss procedure using two bars lying parallel or non-intersecting is use to correct pectus excavatum with varying degrees of patient satisfaction. This bar placement has its limitation for certain pectus excavatum morphology where the deformity is deep and focal or located below the subxiphoid. We have altered our bar placement so that bars intersects in an X or cross manner for such pectus morphology. We describe the X or cross bar placement and its specific indications based on morphology in a series of five patients from February 2019 until December 2019 with symmetrical focal deformity along the xiphisternum and asymmetric deformity below the xiphoid. The operating time varied from 90 to 120 min. There was no significant postoperative morbidity. They are on follow-up with period ranging from 4 to 15 months from the day of surgery. Early results show the X or cross bar Nuss procedure can be safely performed to achieve a desired long-term morphological correction of symmetric deep focal xiphisternal defects or asymmetric deformity below the xiphoid.

Back to the future: a case series of minimally invasive repair of pectus excavatum with regular instruments

OBJECTIVE

Minimally invasive repair of pectus excavatum (MIRPE) is a surgical treatment for PE. During the procedure, a specialized introducer is used to tunnel across the mediastinum for thoracoscopic insertion of a metal bar. There have been reported cases of cardiac perforation during this risky step. The large introducer can be a dangerous lever in unskilled hands. We set out to determine the safety and feasibility of using regular instruments (i.e., not relying on special devices or tools) to create the retrosternal tunnel during MIRPE.

METHODS

This was a preliminary study of MIRPE with regular instruments (MIRPERI), involving 28 patients with PE. We recorded basic patient demographics, chest measurements, and surgical details, as well as intraoperative and postoperative complications.

RESULTS

Patients undergoing MIRPERI had Haller index values ranging from 2.58 to 5.56. No intraoperative complications occurred. Postoperative complications included nausea/vomiting in 8 patients, pruritus in 2, and dizziness in 2, as well as atelectasis, pneumothorax with thoracic drainage, pleural effusion, and dyspnea in 1 patient each.

CONCLUSIONS

In this preliminary study, the rate of complications associated with MIRPERI was comparable to that reported in the literature for MIRPE. The MIRPERI approach has the potential to improve the safety of PE repair, particularly for surgeons that do not have access to certain special instruments or have not been trained in their use.

Nuss procedure in the adult population for correction of pectus excavatum

Minimally invasive repair of pectus excavatum has been successfully modified for use in adult patients. Many patients present in adulthood with progression of symptoms as the chest wall becomes less compliant with age. A thorough workup is completed including echocardiogram and chest CT to evaluate for anatomic abnormalities. Cardiopulmonary exercise testing is done to quantify the physiologic impact. Modifications of the original Nuss procedure required to allow for successful adult repair include the use of forced sternal elevation, the use of multiple bars, medial bar fixation, and interspace support to prevent bar rotation and migration. Occasionally, fractures may occur that require an open procedure and osteotomy or cartilage resection and hybrid approach incorporating the principals of intrathoracic support and osteotomy with bar stabilization.

The Vacuum Bell device as a sternal lifter: An immediate effect even with a short time use

BACKGROUND

To minimize cardiac perforation during the minimally invasive repair of pectus excavatum (MIRPE), several surgeons have suggested using a suction device to intraoperatively lift the sternum. Whether or not this technique is effective for all PE patients is not yet known. As such, our aim was to quantify the extent to which a suction device is capable of lifting the sternum with a short duration of use.

METHODS

30 PE patients received a low-dose CT scan as part of standard PE evaluation. A Vacuum Bell suction was then applied for only two minutes, and a repeat CT scan was obtained only at the deepest point of the chest wall deformity. We compared chest dimensions before and after Vacuum Bell suction.

RESULTS

The Vacuum Bell lifted the sternum in all 29 patients included in the analysis. The absolute change in depth ranged from 0.29 to 23.67mm (M=11.02, SD=6.05). The average improvement in Haller index was 0.76. The suction was most effective for individuals with low BMI and smaller chest depths. Efficacy was not associated with gender, age, or chest morphology.

CONCLUSIONS

The Vacuum Bell device effectively lifted the sternum in PE patients with different demographics and chest morphologies. Future research is needed to address whether or not the device reduces risk of cardiac perforation during MIRPE.

LEVELS OF EVIDENCE

Prognosis Study Level IV.

Nuss Procedure for a Patient with Negative Haller Index

Introduction  Minimally invasive repair for pectus excavatum (MIRPE) is controversial in extremely severe cases of pectus excavatum (PE) and an open repair is usually favored. Our aim is to describe a case of a patient with an extremely severe PE that underwent a minimally invasive approach. Case report  An 8-year-old girl with severe sternum depression was assessed. She had a history of exercise intolerance, nocturnal dyspnea, fatigue, and shortness of breath. Chest computed tomography showed that sternum depression was posterior to the anterior vertebral column; therefore, Haller and correction index could not be measured. Spirometry indicated an obstructive ventilation pattern (forced expiratory volume in 1 second = 74.4%), and echocardiogram revealed a dilated inferior vena cava, mitral valve prolapse with normal ventricular function. After multidisciplinary committee evaluation, a MIRPE approach was performed. All symptoms had disappeared at the 3-month postoperative follow-up; the desired sternum shape was achieved and normalization of cardiopulmonary function was observed. The Nuss bars were removed after a 2-year period. After 18-month follow-up, the patient can carry out normal exercise and is content with the cosmetic result. Conclusion  Nuss procedure is feasible in our 8-year-old patient. In this case, both the Haller and correction index were not useful to assess the severity of PE. Therefore, under these circumstances, other radiologic parameters have to be taken into consideration for patient evaluation.

Development of a computer-aided design and finite-element analysis combined method for customized Nuss bar in pectus excavatum surgery

Pectus excavatum (PEX) is the most common chest deformity in children, which is usually corrected by using the minimally invasive Nuss method. The orthopedic effect of the Nuss operation is mainly evaluated by both the Haller index and the appearance of the chest wall configuration, which is dependent on the operator's clinical experience to a great extent. To improve the orthopedic effect, we proposed a novel method to individually design and optimize the shape of the Nuss bar and to advise its location as well as the incisions. By using the CT imaging data, the three-dimensional model of the PEX thoracic structure is reconstructed, which is further employed in finite element analysis to determine the operation plan. By referring to a healthy person who has similar chest dimensions to the PEX patient, the Nuss bar shape is designed, and according to the finding that the healthy chest wall boundary is almost convex with positive curvature, the Nuss bar shape is tuned to be a convex curve to ensure the orthopedic effect. Finite element analysis is employed to analyze the orthopedic effect and to determine the incision position of the Nuss bar. Experiments were carried out to verify the orthopedic effect of the customized Nuss bar, which showed that this method is more accurate and individualized, compared to conventional methods.

Management of deep pectus excavatum (DPE)

The correction of deep pectus excavatum, with the Nuss procedure, frequently require a series of maneuvers that is inherently dangerous. Herein we describe 10 technical modifications to prevent potential complications. These modified techniques have certain advantages and according to the authors, with these maneuvers the risk of pericardial sac, cardiac injury, bar displacement and complications during the removal of the bar could be markedly reduced.

A clinical decision-making model for repeat surgical treatment of pectus Bar displacement: distance measurement after nuss procedure

Background

Bar displacement is one of the most common and serious complications after the Nuss procedure. However, measurements of and factors affecting bar displacement have not been reported. The objectives of this study were to develop a decision model to guide surgeons considering repeat treatment and to estimate optimal cut-off values to determine whether reoperation to correct bar displacement is warranted.

Methods

From July 2011 to August 2013, ninety bars were inserted in 61 patients who underwent Nuss procedures for pectus excavatum. Group A did not need surgical intervention and Group B required reoperation for bar displacement. Bar position was measured as the distance from the posterior superior end of the sternal body to the upper border of the metal bar on lateral chest radiographs. The bar displacement index (BDI) was calculated using D₀ - D_x / D₀ x 100 (D₀: bar position the day after surgery; D_x: minimal or maximal distance of bar position on the following postoperative days). The optimal cut-off values of BDI warranting reoperation were assessed on the basis of ROC curve analysis.

Results

Of the 61 patients, 32 had single bars inserted whereas 29 had parallel bars inserted. There was a significant difference in age (14.0 ± 7.5 vs. 23.3 ± 12.0, p = 0.0062), preoperative Haller index (HI) (4.0 ± 1.1 vs. 5.0 ± 1.0, p = 0.033), and postoperative HI (2.7 ± 0.4 vs. 3.2 ± 0.5 p = 0.006) between the two groups. The optimal cut-off value of BDI was 8.7.

Conclusions

We developed a BDI model for surgeons considering performing reoperation after Nuss procedure. The optimal cut-off value of BDI was 8.7. This model may help surgeons to decide objectively whether corrective surgery should be performed. The main factors affecting the relationship between bar displacement and reoperation were age and preoperative HI.

Minimally invasive repair of pectus excavatum: analyzing contemporary practice in 50 ACS NSQIP-pediatric institutions

BACKGROUND

Minimally invasive repair of pectus excavatum (MIRPE) is a well-established procedure. However, morbidity rate varies widely among institutions, and the incidence of major complications remains unknown.

STUDY DESIGN

The American College of Surgeons 2012 National Surgical Quality Improvement Program-Pediatric (NSQIP-P) participant user file was utilized to identify patients who underwent MIRPE at 50 participant institutions. Outcomes of interest were overall 30-day morbidity, hospital readmission, and reoperation.

RESULTS

Chest wall repair designated MIRPE accounted for 0.6% (n = 264) of all surgical cases included in the NSQIP-P database in 2012. The median age at surgical repair was 15.2 years. Thoracoscopy was used in 83.7% of cases. No mediastinal injuries or perioperative blood transfusions were identified. The 30-day readmission rate was 3.8%. Three patients (1.1%) required re-operation due to the following complications: superficial site infection, bar displacement and pneumothorax. The overall morbidity was 3.8% with no incidences of mortality.

CONCLUSIONS

This analysis of a large prospective multicenter dataset demonstrates that major complications following MIRPE are uncommon in contemporary practice. Wound infection is the most common complication and the main cause of hospital readmission. Targeted quality improvement initiative should be focused on perioperative strategy to further reduce wound occurrences and hospital readmission.

Experience with FiberWire for pectus bar attachment

BACKGROUND

Minimally invasive repair of pectus excavatum has become an established method for repair of pectus excavatum. Bar displacement or rotation remains the most common complication of this repair requiring return to the operating room.

METHODS

Retrospective review of all patients at a single institution who underwent repair of pectus excavatum using FiberWire for bar stabilization between December 2009 and March 2013 was undertaken.

RESULTS

93 patients underwent minimally invasive pectus repair using FiberWire during the study period. The patients included 73 males and 20 females, with an average age of 14.6years (range 7-21years). Mean operative time was 102minutes (range 56-198minutes). No patients developed wound complications, two patients developed pain because of bar migration and required return to the OR, and no patients had recurrence of their pectus defect because of bar migration during the study period. Median length of follow-up was 17months (range 3-36months).

CONCLUSION

Stabilization of pectus bars using circumferential rib fixation with FiberWire at multiple points on both sides of the bar appears to be effective in preventing bar rotation and displacement, and requires minimal change to the operation as it has been previously described. Early experience shows a low rate of complications.

Perioperative strategies and technical modifications to the Nuss repair for pectus excavatum in pediatric patients: a large volume, single institution experience

BACKGROUND

The safety and efficacy of minimally invasive pectus excavatum repair have been demonstrated over the last twenty years. However, technical details and perioperative management strategies continue to be debated. The aim of the present study is to review a large single-institution experience with the modified Nuss procedure.

METHODS

A retrospective review was performed of patients who underwent primary pectus excavatum repair at a single tertiary hospital via a modified Nuss procedure that included: no thoracoscopy, retrosternal dissection achieved via a left-to-right thoracic approach, four-point stabilization of the bar, and no routine epidural analgesia. Data collected included demographics, preoperative symptoms, operative characteristics, hospital charges and postoperative outcomes.

RESULTS

A total of 336 pediatric patients were identified. No cardiac perforations occurred and the rate of pericarditis was 0.6%. Contemporary rates of bar displacement have fallen to 1.2%. Routine use of chlorhexidine scrub reduced superficial site infections to 0.7%. Two patients (0.6%) with severe recurrence required reoperation. Bars were removed after an average period of 31.7(SD 13.2) months, with satisfactory cosmetic and functional results in 94.9% of cases.

CONCLUSIONS

We report here a single-institution large volume experience, including modifications to the Nuss procedure that make the technique simpler and safer, improve results, and minimize hospital charges.

Technical innovation in minimally invasive repair of pectus excavatum

The aim of study was to introduce technical innovation of MIRPE which reduces the risk of cardiac injury. Modification of MIRPE method with semiflexible thoracoscope and sternum elevating technique has been used. Volkmann bone hook has been inserted percutaneously to the sternum. The hook elevates the sternum forward and enlarges the retrosternal space for safer passage of thoracoscopically guided introducer. Using semiflexible thoracoscope allows better view from various angles via one site of insertion. During the period 2005-2012, the MIRPE was performed on 29 girls and 151 boys; the mean age at the time of surgery was 15.9 years (range 13-18.7 years). The mean Haller index was 4.7 (range 2.7-20.5). The most common complication was pneumothorax (3.3 %) and the incidence of bar displacement was 2 %. The most serious complication was cardiac perforation when inserting Lorenz introducer. This occurred in a 16-year-old girl; she required urgent sternotomy with right atrial repair and recovered well. External elevation of sternum with the hook was used since this case. Subsequent 113 patients underwent surgery without any serious complications. Technical innovation using semiflexible thoracoscope and hook elevation of the sternum reduces the risk of cardiac injury. The hook opens the anterior mediastinum space effectively and makes the following dissection relatively safe and straightforward.

Development of supravalvular pulmonary artery stenosis following a Nuss procedure

We report a case of a 13-year old girl with pectus excavatum who had a Nuss procedure and two years later a new cardiac murmur appeared which on investigation was diagnosed as supravalvular pulmonary artery stenosis. Following removal of the Nuss bar the stenosis resolved.