Recent Modifications of the Nuss Procedure: The Pursuit of Safety During the Minimally Invasive Repair of Pectus Excavatum.

OBJECTIVE: To review standardized Nuss correction of pectus excavatum and vacuum bell treatment over the last 10 years. SUMMARY OF BACKGROUND DATA: In 2010, we reported 21 years of the Nuss procedure in 1215 patients. METHODS: Over the last 10 years, 2008-2018, we evaluated 1885 pectus excavatum patients. Surgery was indicated for well-defined objective criteria. A consistent operation was performed by 8 surgeons in 1034 patients, median 15 years, (range 6-46); 996 were primary, and 38 redo operations. Surgical patients' mean computed tomography index was 5.46. Mitral valve prolapse was present in 5.4%, Marfan syndrome in 1.1% and scoliosis in 29%. Vacuum bell treatment was introduced for 218 patients who did not meet surgical criteria or were averse to surgery. RESULTS: At primary operation, 1 bar was placed in 49.8%; 2 bars, 49.4%; and 3 bars, 0.7%. There were no deaths. Cardiac perforation occurred in 1 patient who had undergone previous cardiac surgery. Paraplegia after epidural catheter occurred once. Reoperation for bar displacement occurred in 1.8%, hemothorax in 0.3%, and wound infection in 2.9%; 1.4% required surgical drainage. Allergy to stainless steel was identified in 13.7%. A good anatomic outcome was always achieved at bar removal. Recurrence requiring reoperation occurred in 3 primary surgical patients. Two patients developed carinate overcorrection requiring reoperation. Vacuum bell treatment produced better results in younger and less severe cases. CONCLUSIONS: A standardized Nuss procedure was performed by multiple surgeons in 1034 patients with good overall safety and results in primary repairs. Vacuum bell treatment is useful.

Indications and guidelines for pectus excavatum repair.

PURPOSE OF REVIEW: The introduction of the Nuss procedure in 1997 for treatment of pectus excavatum, in conjunction with the ever-expanding body of medical information available on the internet, significantly raised the level of awareness for this deformity as both an anatomic and a functional problem. The subsequent increase in referrals for pectus excavatum repair provided large patient series for clinical analyses to better define underlying physiologic impairments and stimulated surgeons to develop technical improvements to enhance the safety and effectiveness of pectus excavatum repair. RECENT FINDINGS: Clinical assessment, diagnostic imaging, and cardiorespiratory testing of patients with pectus excavatum have helped to characterize physiologic impairments associated with severe pectus excavatum and to define inclusion criteria for surgical repair. Appropriate timing of repair is important to minimize complications, especially recurrence. Evidence of improved cardiorespiratory function after pectus excavatum repair has been presented. As a result of numerous technical improvements, safe and effective operative correction of pectus excavatum has been reported for both the Nuss procedure and open repair. SUMMARY: The findings presented in this review provide objective evidence of the cardiorespiratory impairment associated with severe pectus excavatum. Clinical identification of affected patients should prompt timely work-up and referral for pectus excavatum repair if inclusion criteria are met. Regular follow-up through pubertal growth is recommended.

A design for simulating and validating the nuss procedure for the minimally invasive correction of pectus excavatum.

Surgical planners are used to achieve the optimal outcome for a surgery, especially in procedures where a positive aesthetic outcome is the primary goal, such as the Nuss procedure which is a minimally invasive surgery for correcting pectus excavatum (PE)--a congenital chest wall deformity. Although this procedure is routinely performed, the outcome depends mostly on the correct placement of the bar. It would be beneficial if a surgeon had a chance to practice and review possible strategies for placement of the corrective bar and the associated appearance of the chest. Therefore, we propose a strategy for the development and validation of a Nuss procedure surgical trainer and planner.

Selective use of sternal elevation before substernal dissection in more than 2000 Nuss repairs at a single institution.

BACKGROUND/PURPOSE: Evaluate the safety of sternal elevation (SE) used selectively before creating the substernal tunnel during the Nuss procedure. METHODS: An IRB-approved (01-05-EX-0175-HOSP), single institution, retrospective review was performed (1/1/1997-11/20/2017). Primary and secondary Nuss repairs (i.e., previous Nuss, Ravitch, thoracotomy, or sternotomy) are included. SE use, cardiac injuries, and pectus bar infections are reported. Chi square and Fisher's exact test (FE) were used (critical p < .05). RESULTS: 2037 patients [(80% male; mean age 15.2 years (SD = 4.4, range 3-46); mean Haller index (HI) 5.3 (SD = 5.7, range 1.73-201)] underwent Nuss repair. SE was used before creating the substernal tunnel in 171 (8.4%): 160 (8.2%) of 1949 primary and 11 (12.5%) of 88 secondary repairs. SE use increased significantly [χ2(2) = 118.93; p < .001] over time and with increasing HI [χ2(3) = 59.9; p < .001]. No cardiac injuries occurred in primary repairs but two occurred in patients with previous sternotomy. Infection rates were not different with (2.9%) or without SE (1.8%) [χ2(1) =1.14; p = .285] and not higher with off-label VB (1.5%) versus other SE techniques (3.8%) [FE, p = .65)]. CONCLUSION: Selective use of sternal elevation before substernal dissection during the Nuss procedure is safe but may not prevent cardiac injuries in patients with previous sternotomy. Infection rates were not increased with SE. TYPE OF STUDY: Retrospective review. LEVEL OF EVIDENCE: IV.

Ten-year experience with staged management of pectus carinatum: Results and lessons learned.

INTRODUCTION: We report pectus carinatum management over a 10+year period. METHODS: Staged management, with initial bracing and operation for failure or special circumstances, was employed. A newer brace and a minimally invasive operation for PC (the Abramson procedure) were introduced during the study period. RESULTS: Of 695 consenting patients from 2008 to 2018, 265 (38%) were observed. Of 430 treated, 339 (79%) had bracing only; 65 (15%) underwent surgery without a trial of bracing, while 26(5%) underwent surgery after a failed attempt at bracing. Of 364 bracing patients, 144 (40%) were successful, 77 (21%) are ongoing, 25 (7%) failed, and 118 (32%) dropped out. Recurrence was noted in 17 (5%), an average 5.4 months later. Two (0.4%) overcorrected to pectus excavatum (PE). Successful patients experienced a 50% decrease in pressure of correction (POC) beginning one month after starting treatment. Brace failure patients did not. Reported compliance with brace utilization (hours/day) was similar. Surgery was required in 91 patients. Open operations were performed in 61 (67%), Abramson operations in 23 (25%), and Nuss procedure in 7 (8%) who developed excavatum over correction following bracing or who had mixed deformity, with excavatum one side of the sternum and carinatum on the other. Twenty-four (36%) of the surgeries for PC occurred after an attempt at bracing. All obtained good initial results by operation. No recurrence was noted after open operation and 3 (13%) after Abramson. Open complications included 1 (2%) infection. Abramson's operation required 11 (48%) revisions, 6 (26%) early bar removals, and had 3 (13%) infections. CONCLUSION: Brace treatment for PC can be guided by pressure of correction, which fell by more than half in successfully treated patients. POC did not fall in patients who failed. If POC does not fall, surgery should be considered. Open repair of Pectus Carinatum is generally successful, while the Abramson operation has a significant rate of complications with the implants currently available in the U.S. LEVELS OF EVIDENCE: Level III - Retrospective comparative study.

Development and validation of the Pectus Carinatum Body Image Quality of Life (PeCBI-QOL) questionnaire.

INTRODUCTION: While body image disturbances and quality of life in persons with pectus excavatum (PE) have been well documented, very little has been done to systematically measure and document the same in patients with pectus carinatum (PC). Because of this, the current study aimed to develop and validate an instrument to assess body image related quality of life in patients with PC and their parents. METHOD: Participants: Two waves of data collection took place. The development phase enrolled 78 PC patients and 76 matched parents. The validation phase enrolled 50 PC patients and 50 parents. Mean age at the initiation of treatment was 15.14 (SD = 2.54). Participants were mostly boys (85.9%) and White or Caucasian (89.7%). Instrument development, refinement, and validation: A group of 5 experts in chest wall deformities used existing measures of body image disturbances in PE, combined with the broader body image literature, to develop larger item pools for patients and their parents. Item analysis from this phase was used to remove poorly performing or statistically redundant items. In the validation phase, refined patient and parent instruments were examined using exploratory principal components factor analysis (EFA) with parallel analysis for factor retention, followed by Varimax rotation to identify a final factor solution. RESULTS/DISCUSSION: This development and refinement process yielded a final questionnaire for patients (18 items) and parents (15 items). The patient questionnaire includes four subscales, each with good internal consistency: Body Image Disturbance; Treatment Motivation/Engagement; Physical Limitations; and Social Disadvantage. The parent questionnaire includes 3 subscales: Body Image Disturbance; Treatment Motivation/Engagement; Physical Limitations. Patient and parent scales showed moderate correlations. Among patients with measures pre- and posttreatment, there was a significant improvement in overall PeCBI-QOL score. We demonstrate, in this study, that body image and related quality of life can be reliably and validly assessed with the PeCBI-QOL, which has implications for more comprehensively documenting the negative psychological and functional consequences of pectus carinatum. TYPE OF STUDY/LEVEL OF EVIDENCE: Study of diagnostic test/III.

Nonoperative management of pectus excavatum with vacuum bell therapy: A single center study.

PURPOSE: The purpose of this study was to determine variables predictive of an excellent correction using vacuum bell therapy for nonoperative treatment of pectus excavatum. METHODS: A single institution, retrospective evaluation (IRB 15-01-WC-0024) of variables associated with an excellent outcome in pectus excavatum patients treated with vacuum bell therapy was performed. An excellent correction was defined as a chest wall depth equal to the mean depth of a reference group of 30 male children without pectus excavatum. RESULTS: Over 4years (11/2012-11/2016) there were 180 patients enrolled with 115 available for analysis in the treatment group. The reference group had a mean chest wall depth of 0.51cm. An excellent correction (depth≤0.51cm) was achieved in 23 (20%) patients. Patient characteristics predictive of an excellent outcome included initial age≤11years (OR=3.3,p=.013), initial chest wall depth≤1.5cm (OR=4.6,p=.003), and chest wall flexibility (OR=14.8,p<.001). Patients that used the vacuum bell over 12 consecutive months were more likely to achieve an excellent correction (OR=3.1,p=.030). Follow-up was 4months to 4years (median 12months). CONCLUSION: Nonoperative management of pectus excavatum with vacuum bell therapy results in an excellent correction in a small percentage of patients. Variables predictive of an excellent outcome include age≤11years, chest wall depth≤1.5cm, chest wall flexibility, and vacuum bell use over 12 consecutive months. TYPE OF STUDY: Retrospective chart review. LEVEL OF EVIDENCE: Level III treatment study.

Multivariate analysis of risk factors for Nuss bar infections: A single center study.

BACKGROUND/PURPOSE: Our previously published data suggested several risk factors for infection after the Nuss procedure. We aimed to further elucidate these findings. METHODS: An IRB-approved (14-03-WC-0034), single institution, retrospective review was performed to evaluate the incidence of postoperative Nuss bar infections associated with seven variables. These were subjected to bivariate and multivariable analyses. A broad definition of infection was used including cellulitis, superficial infection with drainage, or deep infection occurring at any time postoperatively. RESULTS: Over 7years (4/1/2009-7/31/2016), 25 (3.2%) of 781 patients developed a postoperative infection after primary Nuss repair. Multivariable analyses demonstrated an increased risk of infection with perioperative clindamycin versus cefazolin for all infections (AOR 3.72, p=.017), and specifically deep infections (AOR 5.72, p=.004). The risk of a superficial infection was increased when antibiotic infusion completed >60min prior to incision (AOR 10.4, p=.044) and with the use of peri-incisional subcutaneous catheters (OR 8.98, p=.008). CONCLUSION: Following primary Nuss repair, the rate of deep bar infection increased with the use of perioperative clindamycin rather than cefazolin. The rate of superficial infection increased when perioperative antibiotic infusion was completed more than 60min prior to incision and with the use of peri-incisional subcutaneous catheters. Further studies are needed to better understand these findings. TYPE OF STUDY: Retrospective chart review. LEVEL OF EVIDENCE: Level III treatment study.

Selective versus routine patch metal allergy testing to select bar material for the Nuss procedure in 932 patients over 10years.

AIM OF THE STUDY: The aim of the study was to determine the role of patch metal allergy testing to select bar material for the Nuss procedure. METHODS: An IRB-approved (11-04-WC-0098) single institution retrospective, cohort study comparing selective versus routine patch metal allergy testing to select stainless steel or titanium bars for Nuss repair was performed. In Cohort A (9/2004-1/2011), selective patch testing was performed based on clinical risk factors. In Cohort B (2/2011-9/2014), all patients were patch tested. The cohorts were compared for incidence of bar allergy and resultant premature bar loss. Risk factors for stainless steel allergy or positive patch test were evaluated. MAIN RESULTS: Cohort A had 628 patients with 63 (10.0%) selected for patch testing, while all 304 patients in Cohort B were tested. Over 10years, 15 (1.8%) of the 842 stainless steel Nuss repairs resulted in a bar allergy, and 5 had a negative preoperative patch test. The incidence of stainless steel bar allergy (1.8% vs 1.7%, p=0.57) and resultant bar loss (0.5% vs 1.3%, p=0.23) was not statistically different between cohorts. An allergic reaction to a stainless steel bar or a positive patch test was more common in females (OR=2.3, p<0.001) and patients with a personal (OR=24.8, p<0.001) or family history (OR=3.1, p<0.001) of metal sensitivity. CONCLUSION: Stainless steel bar allergies occur at a low incidence with either routine or selective patch metal allergy testing. If selective testing is performed, it is advisable in females and patients with a personal or family history of metal sensitivity. A negative preoperative patch metal allergy test does not preclude the possibility of a postoperative stainless steel bar allergy. LEVEL OF EVIDENCE: Level III Treatment Study and Study of Diagnostic Test.

Use of an Optical Scanning Device to Monitor the Progress of Noninvasive Treatments for Chest Wall Deformity: A Pilot Study.

BACKGROUND: The nonsurgical treatment of chest wall deformity by a vacuum bell or external brace is gradual, with correction taking place over months. Monitoring the progress of nonsurgical treatment of chest wall deformity has relied on the ancient methods of measuring the depth of the excavatum and the protrusion of the carinatum. Patients, who are often adolescent, may become discouraged and abandon treatment. METHODS: Optical scanning was utilized before and after the intervention to assess the effectiveness of treatment. The device measured the change in chest shape at each visit. In this pilot study, patients were included if they were willing to undergo scanning before and after treatment. Both surgical and nonsurgical treatment results were assessed. RESULTS: Scanning was successful in 7 patients. Optical scanning allowed a visually clear, precise assessment of treatment, whether by operation, vacuum bell (for pectus excavatum), or external compression brace (for pectus carinatum). Millimeter-scale differences were identified and presented graphically to patients and families. CONCLUSION: Optical scanning with the digital subtraction of images obtained months apart allows a comparison of chest shape before and after treatment. For nonsurgical, gradual methods, this allows the patient to more easily appreciate progress. We speculate that this will increase adherence to these methods in adolescent patients.

Pectus excavatum repair after sternotomy: the Chest Wall International Group experience with substernal Nuss bars.

OBJECTIVES: Patients with pectus excavatum (PE) after prior sternotomy for cardiac surgery present unique challenges for repair of PE. Open repairs have been recommended because of concerns about sternal adhesions and cardiac injury. We report a multi-institutional experience with repair utilizing substernal Nuss bars in this patient population. METHODS: Surgeons from the Chest Wall International Group were queried for experience and retrospective data on PE repair using sub-sternal Nuss bars in patients with a history of median sternotomy for cardiac surgery (November 2000 to August 2015). A descriptive analysis was performed. RESULTS: Data for 75 patients were available from 14 centres. The median age at PE repair was 9.5 years (interquartile range 10.9), and the median Haller index was 3.9 (interquartile range 1.43); 56% of the patients were men. The median time to PE repair was 6.4 years (interquartile range 7.886) after prior cardiac surgery. Twelve patients (16%) required resternotomy before support bar placement: 7 pre-emptively and 5 emergently. Sternal elevation before bar placement was used in 34 patients (45%) and thoracoscopy in 67 patients (89%). Standby with cardiopulmonary bypass was available at 9 centres (64%). Inadvertent cardiac injury occurred in 5 cases (7%) without mortality. CONCLUSIONS: Over a broad range of institutions, substernal Nuss bars were used in PE repair for patients with a history of sternotomy for cardiac surgery. Several technique modifications were reported and may have facilitated repair. Cardiac injury occurred in 7% of cases, and appropriate resources should be available in the event of complications. Prophylactic resternotomy was reported at a minority of centres.

Risk factors and management of Nuss bar infections in 1717 patients over 25 years.

PURPOSE: An increase in postoperative infections after Nuss procedures led us to seek risks and review management. We report potential risk factors and make inferences for prevention of infections. METHODS: An IRB-approved retrospective chart review was used to evaluate demographic, clinical, surgical, and postoperative variables of patients operated on between 10/1/2005 and 6/30/2013. Those with postoperative infection were evaluated for infection characteristics, management, and outcomes with univariate analyses. RESULTS: Over this 8-year period (2005-2013), 3.5% (30) of 854 patients developed cellulitis or infection, significantly more than 1.5% (13) in our previous report of 863 patients, 1987-2005 (p=.007). The most frequent organism cultured was methicillin-sensitive Staphylococcus aureus. Patients who were given clindamycin preoperatively (5 of 26 patients) had higher infection rates than those who received cefazolin (25 of 828) (19% vs 3%, p<.001). Patients treated with a peri-incisional ON-Q (I-Flow, Kimberly-Clark, Irvine, CA) also had higher infection rates (8.3% vs 2.4%, p<.001). Of the 30 patients who developed an infection, eighteen (60%) with cellulitis or superficial infections did not require surgical treatment or early bar removal. The other twelve patients (40%) with deep hardware infections required an average of 2.2 operations (range 1-6), with 3 (25%) requiring removal of their stabilizer and 3 (25%) requiring early bar removal. None of these three patients experienced recurrence of pectus excavatum at 2 to 4 years of follow-up. CONCLUSION: Preoperative antibiotic selection and use of ON-Q's may influence infection rates after Nuss repair. Nuss bars could be preserved in 90% of all patients with an infection and even 75% of those with a deep hardware infection. Attempts to retain the bar when an infection occurs may help prevent pectus excavatum recurrence. Level of Evidence=III.

High rates of metal allergy amongst Nuss procedure patients dictate broader pre-operative testing.

PURPOSE: A previous study from our group estimated that as few as 2.2% of pectus excavatum patients suffered from allergy to the implanted metal bar. We sought to assess recent changes in incidence of metal allergy and identify the benefit of metal allergy testing prior to surgery. METHODS: A retrospective review was performed of all consenting patients undergoing pectus repair during the six years between 9/2004 and 12/2010 at our institution. Incidence was based on clinical symptoms and/or T.R.U.E.® patch testing. Demographic data, history of atopy and history of metal allergy were collected. Type and number of bars used, suture site infection, skin rash and wound infection rates were reviewed. RESULTS: Forty one of 639 patients (6.4%) had clinical or patch test evidence of metal allergy. Family history of metal allergy and pre-operative history of metal sensitivity were found to be statistically significant correlates. CONCLUSIONS: The rate of metal allergy in the pectus excavatum population may be higher than previously reported. Patient or family history of metal allergy or metal sensitization may indicate increased risk. Metal allergy testing should be performed before Nuss procedure.

Staged management of pectus carinatum.

AIM: The aim was to report the treatment of pectus carinatum with a novel Argentine brace and operation. METHODS: The bracing and clinical data of 137 consenting pectus carinatum patients treated between October 2008 and December 2011 were reviewed for outcome. Institutional approval was obtained. Data are reported as median (range). RESULTS: Median age 122 bracing patients was 14 (10-28)years with 67 (55%) progressing under active treatment. Five patients (4%) were lost to follow-up, and thirteen (11%) failed treatment. Thirty-seven patients (30%) exhibited flattening of the sternum after 6 (1-24)months without surgery. After flattening, patients then wore the brace for progressively fewer hours each day as a "retainer" for 5 (3-19)months. Five patients (4%) experienced recurrence 5 (3-7)months after brace treatment was discontinued. Complications were limited to transient skin breakdown in nine patients. Three of the 13 Argentine brace failures and 15 other pectus carinatum patients were treated surgically. Thirteen underwent Abramson's minimally invasive operation and five an open repair, all with good initial correction. For Abramson repairs, seven patients have had bars removed, with results rated as excellent (n=4), good (n=2), and failure (n=1, converted to open with excellent result later). In three patients with stiff chests, costal cartilage was resected thoracoscopically during the Abramson repair with measurably improving compliance. CONCLUSION: Staged treatment of pectus carinatum allows most teenagers to be managed non-operatively. For patients who fail bracing or are not amenable to bracing, minimally invasive surgical treatment for pectus carinatum is a viable option.

Extraluminal use of the Arndt pediatric endobronchial blocker in an infant: a case report.

PURPOSE: Attaining lung isolation in the infant undergoing thoracic anesthesia can be challenging for the anesthesiologist. We describe a novel approach to performing lung isolation in an infant undergoing thoracotomy for lobectomy using an Arndt pediatric endobronchial blocker via an extraluminal technique. CLINICAL FEATURES: Lung isolation in an infant was achieved through the use of an Arndt pediatric endobronchial blocker placed externally to an endotracheal tube. The blocker's placement was facilitated through the use of a pediatric fibreoptic brochoscope placed through the guidewire of the extraluminally placed bronchial blocker. CONCLUSION: This novel technique may provide an easier and more reliable method of attaining single lung ventilation in infants and small children.