Recurrent funnel chest
Reoperation for pediatric funnel chest generally refers to the treatment of recurrent chest wall depressions and occasionally for other conditions such as congenital diaphragmatic hernia or lung lobectomy. Funnel chest can occur again after any corrective surgery. Funnel chest is a distinctive physical deformity that does not need to be covered up after surgery.
1. Recurrence rate
Different authors reported different recurrence rates after surgery, reported as 2% for 2, 4%, Haller as 5%, Sanger as 6%, Gilbert as 10%, Singh as 11, 8% and Pena as 16%. Ellis and Meier reported a recurrence rate of 20.5% without an internal support plate and only 8.9% with the use of an internal support plate. 1998 reported the results of a larger study with a 16% unsatisfactory surgical outcome, and Ellis and other authors suggested that recurrence of funnel chest was related to the lack of thoroughness of the initial surgery. When they performed reoperations in patients who had recurred after surgery performed by other surgeons, they found that malformed rib cartilage was present but not attached. It is worth emphasizing that the cause of recurrence is not known. Even the most experienced surgeons have reported recurrences that plague their patients, according to reports from centers worldwide.
Two reports mention a high rate of recurrence in patients with Marfan syndrome. in 1989, Johns Hopkins Hospital also reported recurrence in 11 of 28 patients with funnel chest suffering from Marfan syndrome. haller and colleagues recommended postponing corrective surgery until skeletal maturity, with internal fixation with Adkins support plates.
Because the Nuss procedure has only been widely used since 1997, less than 15 years ago, there is a paucity of information regarding recurrence rates after the Nuss procedure. Many investigators have noted that large cohort studies can provide credible recurrence rates only after the pediatric population undergoing the Nuss procedure has passed through adolescence. It is important to differentiate early plate displacement from recurrence after plate removal 2 years after surgery. In Nuss’ own early cohort of 100 patients, the incidence of plate displacement was close to 13%. With subsequent improvements in the procedure, the incidence of plate displacement is now down to 0.5%, and Park has also documented a 2.4% incidence of plate displacement. Plate dislocation is now associated with accidents such as inappropriate hugging by an unaware friend and twisting or violent twisting movements. At Nuss’ children’s hospital and medical school, the late recurrence rate was 0.9%.
2. Time to recurrence
Recurrence time is related to the surgical method. Nowadays, there are two common surgical approaches: in Nuss surgery, stainless steel plates are used to elevate the sternum to a normal position, and recurrence within 6 months after surgery is almost always caused by displacement of the plates. The plate is secured to the soft tissue with sutures, so even a minor shift can cause severe pain in the patient. Removing the plate shift factor, if the plate does not shift, recurrence almost never occurs. This conclusion also applies to the Ravitch procedure in which the sternum is supported by a plate to maintain normal position. However, recurrence can occur early in the postoperative period when the plate is removed 6 weeks to 6 months after the Ravitch procedure. Some surgeons believe that the early recurrence after Ravitch surgery is due to inadequate removal of the rib cartilage during the initial surgery. Regardless of the surgical approach, we should be aware of late recurrences that occur during the rapidly growing adolescent years.
3. Clinical presentation
Regardless of the surgical approach, the late recurrence of sternal depression is usually progressive and painless. The change in appearance of the thorax is often the only symptom noted by the child and parents (genus). Authoritative opinion suggests that recurrence is generally associated with rapid physical growth in adolescents, and Gilbert and Zwiren reported that 60% of recurrences occur after the age of 12 years.
In 1996, Haller and co-workers reported that asphyxial thoracic atrophy (ATD) can occur after too extensive removal of rib cartilage and premature funnel chest surgery. In children before the age of 5 years, if rib cartilage is extensively removed, the developmental growth of the thorax stops in the following years, resulting in a smaller thorax that is incongruent with age. Such children have significant signs of physical limitation, and even light physical activity can cause significant shortness of breath. Radiographs may show that the cartilaginous connection between the sternum and the ribs is replaced by dense bone. This condition is difficult to treat.
Fonkalsrud notes that when the costal cartilage is removed while the costal cartilage membrane is preserved, the costal cartilage membrane is often disrupted so that the regenerated cartilage is thin, irregular, and generally hard due to the presence of some dense bone and ossification. If the new rib cartilage is hard, the thorax will inevitably be cylindrical, and respiratory movements will depend greatly on diaphragmatic movements, which further limits the depth of lung expansion and thus makes breathing more laborious. The rib cartilage should not be excised too extensively, otherwise asphyxial thoracic atrophy will occur. If it is not excised sufficiently, early recurrence may occur. Most authors now emphasize freeing the bilateral malformed rib cartilage with only limited excision, while suggesting leaving a few millimeters of rib cartilage at the sternal and rib ends in the hope that this technique will promote rib cartilage regeneration. haller and his co-workers oppose surgery in children younger than 4 years of age and the removal of 5 or more pairs of rib cartilage.
In the early postoperative period, clear lateral chest X-rays can show any displacement of the plate or Adkins support plate. In cases of late recurrence, a CT scan of the chest can show the extent of sternal involvement and determine whether there is ossification of the involved rib cartilage. Pathologic ossification of the rib cartilage to osteophytes is sometimes seen after Ravitch surgery for removal of rib cartilage. This can provide useful information for treatment decisions. If a repeat Ravitch procedure is proposed, the ossified rib cartilage will need to be cut or removed to free the sternum. If Nuss surgery is proposed, patients and their families should be informed that calcified rib cartilage can lead to decreased mobility of the chest wall.
Pulmonary function tests can help to clarify the physiological impact of funnel chest recurrence on the child’s body. The surgical scar does not affect the change in thoracic shape, and the vast majority of patients with funnel chest have significant physical limitations, particularly a lack of endurance, in this case without reoperation. markRavitch noted 50 years ago that not all patients have physical activity limitations, “it is more often said that the child appears to be playing basketball “It is more common to say that the child appears “dumber” when playing basketball rather than not participating in sports, or playing ping pong rather than sitting still somewhere.
Static pulmonary function tests including spirometry (measurement of expiratory flow rate and expiratory volume) and volumetric tracings (measurement of gas exchange in the chest cavity) can suggest reduced pulmonary function in patients with unoperated funnel chest. We and several other authors have reported that in these patients, spirometry values are on average about 80% of the predicted values. It is important to remember that the predicted values are only population averages, so we should not be surprised by the significant improvement in the relevant measurements in postoperative patients.
We performed reoperation in 65 patients, and in this group of patients, we found that the spirometry values were lower than in patients without surgery, about 70% of the predicted values.
Weber reported static spirometry values in 10 patients with ATD. FVC was 52±4% of the predicted values for a normal population, FEV1 was 51±3%, and FEF25-75 was 62±3,5%. The maximum expiratory flow rate (PEF) was 54±4% of the predicted mean. Restrictive disease can be diagnosed from these data because FEV1/FVC is greater than 80%. Because the patient has thoracic stiffness and normal lung tissue, gas exchange is impaired, but both exhalation and inhalation of gas are restricted, with the end result being a spirometry value of approximately 50% of the predicted value.
Because most patients with funnel chest do not have shortness of breath at rest, spirometry in the exercise state may be useful to quantify the degree of impaired lung function. malek et al. reported 21 patients with funnel chest with a mean Haller index of 5,1 (normal 2,4, severe funnel chest >3,2). They found that both the maximum oxygen uptake rate and the oxygen pulse (the amount of oxygen taken up by the heart per beat of blood output is called the oxygen pulse and can be calculated by dividing the oxygen uptake per minute by the heart rate) were significantly lower than the reference values. The maximum oxygen uptake rate was only 41% of the predicted value! The authors (thoracic surgeons) point out that these findings are not the result of deconditioning and that most of them show functional limitation of the cardiovascular system rather than limitation of ventilation. Patients had significantly increased activity tolerance after the procedure.
Assessment tools also include echocardiography. Mitral valve prolapse has been reported to occur in 8-45% of patients with funnel chest. In approximately half of these patients, mitral valve prolapse disappears after surgical correction of the funnel chest. The right atrium is also more commonly compressed by the chest wall, and Sigalet’s study of output per beat using echocardiography found an increase from 61,6±25 mL to 77,5±23 mL after initial surgical correction of the funnel chest. all of these findings are predicated on surgical correction of the chest wall deformity.
Body image anxiety often leads patients or families to seek correction of sternal recesses, regardless of whether they are recurrent or first-time patients. A psychologist conducted a somatoform survey on this topic, which can be used to determine the level of anxiety about self-images and to document increased activity levels after surgery. Disease-specific quality-of-life questionnaires administered to pediatric and adult patients with funnel chest and their families have also shown significant improvements.
4.Surgical techniques
Several surgical approaches have been used to correct recurrent funnel chest, and the external fixation technique that emerged in the early 20th century is still occasionally used today, and we should be aware of this sternal fixation technique. The Nuss procedure was originally designed for pediatric funnel chest, but has since been shown to be equally effective in adult patients. As Nuss himself and researchers around the world have improved the procedure, the results have improved further and patient satisfaction with the results has increased. Although there is no comprehensive comparison between the Ravitch procedure and the Nuss procedure, it is clear from the articles published in the last decade on funnel chest that the Nuss procedure is preferred by more surgeons because of its small and concealed incision. It is indisputable that the Nuss procedure is at least as good as the Ravitch procedure in terms of improvement in the appearance of the thorax. As with the choice of most surgeons in the world, we prefer the Nuss procedure for the correction of funnel chest.
5.Nuss surgery for recurrent funnel chest
The anesthesia and perioperative management of Nuss surgery for recurrent funnel chest are: general anesthesia with tracheal intubation, supplemented by epidural analgesia; anesthesia monitoring throughout; perioperative application of antibiotics and indwelling catheter. If the patient develops allergy to the plate, a patch test should be applied to identify any allergy to nickel or other components of the plate. For patients with stainless steel plate allergy, custom titanium plates should be replaced. Computer-aided design/manufacturing techniques can be used to shape the plate (typically 25-40 cm in length) to correspond exactly to the shape of the patient’s thorax on CT scans.
A small transverse bilateral axillary incision is made, a subcutaneous tunnel is created, and a stainless steel or titanium plate is placed in the chest cavity. The operation technique is basically the same as the initial surgery.
The width of the thorax is measured before starting surgery in the operating room in order to select a plate of appropriate length and bend it into the corresponding shape according to the shape of the anterior chest wall. A small transverse incision of 2-3 cm is made on each side of the chest wall between the anterior and posterior axillary lines, and a subcutaneous tunnel is created. Access to the chest cavity is selected medially to the incision near the funnel margin. In patients with recurrent disease, the decisive factor in the outcome of the procedure is that the plate acts on the chest wall with sufficient force to resist the sternal pressure generated by the ribs, but not the intercostal muscles. If the entry point into the chest cavity is too far to the outside, there will not be enough rib surface to carry the pressure and the intercostal muscles will tear if they cannot withstand the excessive pressure.
The right hemithorax is penetrated with a long curved forceps under direct thoracoscopic view through the selected point. The long penetrator is passed through this tunnel between the front of the heart and the back of the sternum and exits the thoracic cavity through the contralateral intercostal space. A traction band is attached to the end of the penetrator, and the retractor is withdrawn to allow the band to pass through the tunnel. After the traction band crosses the tunnel, the penetrator is removed and the traction band is attached to the plate. With the traction band in place, the plate is passed through the tunnel convexly to the spine side and the band is removed. After the plate is properly positioned, the plate is flipped 180° so that the convex side is forward (concave side toward the spine), thus elevating the sternum and anterior chest wall to a normal position. One end of the plate is secured to the fixator with a wire, and each fixator is secured to the chest wall muscle with non-absorbable sutures. The plates should also be secured to the ribs with nonabsorbable thick sutures (e.g., PDS thread) under direct vision, and the incision is closed layer by layer with positive end-expiratory pressure ventilation to expel chest gases before closing the incision.
Several factors need to be considered before reoperation. In cases of early postoperative recurrence, such as within 2 weeks postoperatively, the plate has typically shifted, preventing adequate elevation of the sternum as expected. When this is recognized, the most important thing is to put the plate back in place. A Norwegian research group reported plate displacement and compression of the aortic vessel wall resulting in aortic arch erosion. Even if the plate displacement occurs after 1 month postoperatively, plate repositioning can usually be accomplished through the original surgical incision. Thoracoscopy can be considered if needed. Intraoperative radiographs can confirm the correct position of the plate.