Pectus Carinatum: An Orthotic Approach

Gina M. Retallack, CO; Certified Orthotist, Pediatric Specialist, Hanger Clinic, Lafayette, CO David M. Notrica, MD, FACS, FAAP; Trauma Medical Director, Phoenix Children's Hospital, Phoenix, AZ Dawn E. Jaroszewski, MD; Division of Cardiothoracic Surgery, Department of Surgery, Mayo Clinic, Phoenix, AZ


Pectus Carinatum (PC)

Pectus carinatum (PC) is an anterior chest wall deformity associated with abnormal growth and development of the costal rib cartilages and sternum. The cartilaginous overgrowth is observed as an outward protrusion, tilt, or convexity on the anterior chest wall and often includes the sternum and associated ribs. The prominence may be either asymmetrical or symmetrical. Classification is determined by the physicality of the anterior chest wall and based on the location of prominent versus depressed areas. Accurately identifying the type of PC deformity is a crucial step in predicting orthotic outcomes.

PC Types

There have been several methods of PC classification determined and published over the last 20 years. 3, 7, 10, 15 Each classification system is based on the location of the apical or highest point of the prominence. The currently recognized classification system of PC is comprised of two categories which are differentiated by the location of the involved deformity 3 :

  1. Chondrogladiolar (CG)
  2. Chondromanubrial (CM)

Chondrogladiolar PC (CG) affects the mid- to lower portion of the anterior chest wall, and is the more common of the two. The prominence may include the inferior costal cartilages and portions of the gladiolus ( Fig. 1 ). An asymmetrical version of CG often occurs with both an excavatum and carinatum component and is characterized by a unilateral protrusion with contralateral depression. 16

Chondromanubrial PC (CM), in contrast, affects the upper portion of the ribcage and is more likely to be symmetrical. It is substantially less common than CG, representing only 5% of PC cases. 5 It typically involves the superior costal cartilages, ribs 1-3, and the manubrium. The upper section of the sternum protrudes anteriorly, and the body of the sternum deviates posteriorly ( Fig. 2 ).

Flexibility

In the CG type, the deformity is significantly more flexible due to its inferior location on the anterior ribcage. The longer ribs and accompanying cartilage in the lower sections of the ribcage results in a more flexible deformity because of the mechanical advantage of distance from the sternoclavicular attachments ( Fig. 3 ). CG PC can be effectively treated orthotically until full stature is achieved, and even later. The correction potential is greater due to the combined effect of significant cartilage flexibility and the associated mechanical advantage that persists even after full growth. Orthotic treatment has been shown to have superior results in children with CG types, due to its inherent flexibility and compliant nature. 3, 7, 10

The CM type represents a more rigid type of PC because of its superior location on the ribcage. The upper portion of the ribcage is composed of shorter, less flexible ribs reducing the overall flexibility of the CM deformity ( Fig. 3 ). Orthotic outcomes are less optimal for patients with CM deformities due to the less yielding structure of the superior ribcage. To increase the chance of success, it is worthwhile to initiate orthotic treatment early, preferably during childhood or at the beginning of adolescence when the residual cartilage in this area is more abundant. team prior to the prescription of the frame.

Epidemiology

The incidence of PC is 1:1000 teenagers and is predominantly observed in males. 2 At this time, no definitive etiology of PC has been determined, however medical professionals have observed an increased family history of pectus deformities (25%) suggesting a genetic linkage. 8 In addition, PC has the potential to occur in association with scoliosis (21%) and other inherited connected tissue disorders such as, Marfan's syndrome, Ehlers-Danlos syndrome, Noonan's syndrome, and Poland's syndrome. 1 PC may also be categorized based on etiology:

  1. Post-surgical: After a sternotomy or chest trauma, the sternum does not heal in the proper position, resulting in a prominence on the anterior chest wall, albeit an uncommon occurrence. A post-surgical PC deformity will not progress or change with time.
  2. Congenital: Premature fusion of segments of the sternum can occur in newborns, presenting with a rounded, prominent chest. This deformity has the potential to progress in later years.
  3. Idiopathic: The most common cause and the primary focus of this article. In idiopathic PC, the deformity will typically present during active growth stages between 11-15 years of age. The deformity tends to increase in magnitude concurrently with adolescent growth spurts. Orthotic treatment appears to be most effective in halting progression and achieving skeletal correction during this period of active growth.

PC is often asymptomatic in nature, however some patients complain of significant pain at the costochondrial junction. 9 In some moderate to severe cases of PC, decreased stamina and rapid fatigue during strenuous activity has been reported. 6 Decreased exercise tolerance could potentially be related to the increased diameter and rigid expansion of the chest wall which creates a challenge for the thorax to use normal chest muscles for breathing. 3, 6 As a result, accessory muscles are recruited causing respiration inefficiencies.

The psychological issues of the deformity usually trump all physical symptoms for a young adult. Many PC patients complain of significant body image disturbances and often avoid showing their chest in public. PC may damage their self-image and confidence. Many of our patients initiate body building to mask the deformity. Bulking up the pectoral muscles balances the prominence and helps conceal the deformity. The psychological and social challenges of the deformity are usually the primary reasons patients seek medical attention. The resulting eagerness to initiate orthotic treatment is often helpful in assuring compliance.

Treatment

Surgery had been the primary mode of treatment for the past 50 years. Accepted surgical techniques include excision of the deformed cartilage with sternal osteotomy and internal fixation. Complications reported from surgery include poor long term outcomes, lengthy recovery time, and potential for recurrence. 16 In addition, restricted growth in the thoracic cavity has been noted due to the scarring and rigidity caused by the operation. 14 Consequently, surgical resection has been reserved for the most severe and complicated cases due to its invasive nature. Alternative methods of treatment were prompted as a result, and the development of a "compressive chest brace" was introduced to conservatively address adolescent PC in order to avoid such issues and complications. 11

Non-surgical methods to treat PC were first initiated and applied in the 1970's. Plaster casts were originally used to apply pressure on the prominence to prevent further progression and promote correction. Videl et al initiated these treatments in 1977 with limited success, but provided the ingenuity behind more non-surgical treatments. 18 In 1979, the dynamic chest compressor (DCC) brace was introduced by Dr. Haje and Dr. Raymundo from Brazil, as a means to successfully treat PC with a custom orthosis. 11 They were the first team to develop a custom-fitted orthosis and document and publish its success. In 2000, Dr. Egan described radiographic proven success in treatment of PC with an orthosis. 3 His publication was followed by the first series of successful cases published by surgeons at Cincinnati Children's Hospital demonstrating that compression bracing was safe and effective. 7 Numerous other studies have been published in the last 20 years illustrating different methodologies, outcome measures, and results. 3, 7, 10, 12, 14, 15 Overall, orthotic treatment is now widely accepted as an effective and conservative method of treatment for PC.

Orthotic Treatment Biomechanics

When orthotic treatment is initiated, the patient is typically in their adolescent years. During this growth period, the ribcage is capable of significant flexibility and remodeling capacity. This flexibility allows the prominent areas of the sternum and costal cartilages to be pushed back into the thorax by the anterior/posterior (A/P) forces provided by the PC orthosis. The design of a PC orthosis is based on the principles of Wolff's Law; when healthy bone and cartilage are being loaded with a constant and increasing force, they will adapt, strengthen, and gradually remodel under pressure. The orthosis has two opposing forces, one directly over the apex of the prominence and one on the thoracic spine, directly countering and parallel to the other. Over time, this continuous force applied to the prominence arrests further anterior cartilaginous growth and gradually remodels the ribcage into a more normal, flattened shape. The PC orthosis is worn until skeletal maturity is reached; at this time is when permanent correction can be achieved, and the orthosis can be discontinued. These biomechanical principles have been validated in the design of two different PC orthoses we currently utilize for our PC orthotic treatment; one being a prefabricated design and the other being a custom design.

Prefabricated PC Orthosis

The prefabricated PC orthosis used on our patients was the Trulife Pectus Carinatum Orthosis (Trulife; Seattle, WA). It is a low-profile design with an anterior panel (3 1/2" x 4 1/4") for a posterior-directed force, a posterior panel (6" x 4 3/4") for an anterior-directed force, and four lateral padded panels that contour around the chest ( Fig. 4A , Fig. 4B ). The panels are made from a low density polyethylene (1/8"), which is flexible enough to easily conform around the patient's chest, creating an intimate and concealed fit. Over time, the body heat emitted from the patient helps mold the plastic panels around the chest for further customization. The panels are covered in a foam liner (1/4" - 3/8" thickness) providing additional comfort for the patient. The panels are mounted on aluminum bars (3/4" wide) with growth extensions, making it possible to adjust the circumference and fit of the orthosis as needed. Since the Trulife PC Orthosis only comes in a "universal" size, the aluminum growth extensions promote ample adjustability during treatment and accommodate any anatomical changes that may occur during the patient's growth years.

The anterior and posterior sections of the orthosis are connected by a tension system comprised of bilateral ratcheting buckles. There are two ratchet buckles riveted onto the anterior lateral panels that have connecting ladder straps riveted onto the posterior lateral panels. By tightening the ratchets bilaterally, A/P forces are directed on the pectus deformity. The ratchets have a quick release lever which makes it simple to loosen or remove the orthosis. The shape and design of the lateral pads provides a seamless contour around the patient's chest creating a streamline fit that the patient can appreciate.

Custom PC Orthosis

The custom PC orthosis used on our patients was fabricated by Hanger's National Lab, in Tempe, AZ ( Fig. 5A , Fig. 5B , Fig. 5C ). A motion tracking laser scanner (Insignia TM ) was used to obtain a digital mold of the patient's chest. In conjunction with computer-aided design (CAD) software, Insignia TM can accurately portray a cross-sectional model of the patient's surface anatomy within a millimeter of error. The scan is then electronically sent to Hanger's Central Design Center (CDC), where it is evaluated and modified in CAD software. A three-dimensional foam carving is produced from the final image, providing a positive mold for Hanger's Tempe Lab to create and fabricate the PC orthosis. The custom orthosis has an anterior and posterior panel anchored to aluminum bars that contour around the patient's chest clearing the skin. Lateral ratchet buckles and ladder straps connect the anterior and posterior sections and provide a tightening system. All components and materials of the orthosis can be hand-selected and customized to the patient. However, if not specified, the standard materials are 5/8" poron lined kydex A/P panels, 1" x 1/8" aluminum bars, and 3/4" buckles with 5/8" x 8 1/2" ladder straps. Each panel is customized to the shape and size of the patient's prominence and anatomy. If required, revision and adaptation to anatomical change during treatment can be achieved by adjusting the contours of the aluminum bars.

Custom vs. Prefabricated

Prefabricated When deciding between the prefabricated and custom version, it's crucial to perform an accurate clinical and visual evaluation of the patient's deformity and chest anatomy. The thoracic surgeon and orthotist will collaborate to determine the design of the orthosis at their initial evaluations with the patient. A custom PC orthosis would be indicated for patients with a moderate to severe PC deformity. Patients with an atypical or asymmetric prominence, abnormal shape/size to the deformity, unconventional body shape/size may benefit from a custom designed orthosis. Additionally, young children, patients with overdeveloped muscle build (especially the pectoralis major and latissimus dorsi muscles), and females with developed breast tissue may require customized bracing. With a custom PC orthosis, it's possible to finely contour the aluminum bars around the chest anatomy, thereby providing the appropriate clearance for a female's breasts or an athletic male's chest.

In contrast, the prefabricated design has a very intimate fit to the body, however does not provide the appropriate clearance for chest characteristics such as developed breasts or significant thoracic musculature. The prefabricated design is indicated for a patient with a mild, moderate, or severe PC deformity, normal muscle build, and a prominence which allows a reasonably broad contact area with the anterior pad. Overall, the prefabricated version is slightly less bulky than the custom, and in turn, usually perceived more favorably by the patient.

Undergarment

A Knit-Rite protective body sock is worn under the orthosis, as an interface garment to provide maximum comfort to the patient. The body sock is made from Lycra, CoolMax, and X-Static fibers which in combination helps inhibit body odor, transfer heat and moisture away from the skin, and keep the patient dry. In addition, the silver fibers embedded in the body sock produces an antimicrobial material that inhibits the growth of bacteria. The undergarment is seamless, anti-static, wrinkle free, and stretches in all directions providing a tight fit that helps suspend the orthosis and minimize excess movement or shifting. With the continuous contact and pressure that is applied to the prominence when the orthosis is being worn, normal pressure marks can appear on the skin under the anterior and/or posterior panels. The soft interface the body sock provides reduces skin issues for the patient during orthotic treatment. The Knit-Rite body sock is an integral component of the PC orthotic protocol, addressing the common skin issues caused from heat, pressure, and hygiene.

Clinical Evaluation

Pectus carinatum can appear at any time during adolescence and cannot be predicted or prevented. Once the prominence shows signs of progression and has been evaluated by a physician, orthotic treatment can be initiated. The treatable age for orthotic intervention is approximately from ages 6 to 18, or until skeletal maturity is achieved and the prominence is no longer deformable. For most patients, the ideal age to initiate treatment is between 11-13 years old, close to the onset of puberty. During the clinical evaluation, a detailed medical history is obtained and a physical examination is performed. Personal background information includes: (1) demographics: sex, age, and date of birth; (2) physical characteristics: height, weight, extremity flexibility tests, sternal flexibility, and PC type; (3) medical history: associated symptoms, heart murmurs, prior surgeries, family history of pectus deformities, Marfan Syndrome, unexpected early deaths, age the defect was first noted, signs of progression, and secondary medical conditions.

The physical examination includes a manual compression test, described and validated by Dr. Sydney Haje and Dr. Richard Bowen in 1992, to determine the level of residual flexibility in the chest wall. With one hand firmly on the prominence and the other hand supporting the thoracic spine, gentle manual compression is induced to verify the degree of flexibility. Haje states that if partial or complete reduction is observed, the deformity is considered "flexible". He then categorized the degree of flexibility by dividing it into two subgroups, patients with a "flexible" or a "rigid" protrusion. Determining the flexibility of the chest wall prior to treatment is helpful in predicting clinical outcomes.

Clinical photographs and anthropometric measurements are taken at each appointment to track physical changes and create a chronological, visual and quantitative record of the patient's progress for objective comparison. Clinical photographs are taken with a digital camera and hard copies stored in the patient's file for analysis. Multiple angles of the patient's chest are recorded including: (1) anterior view; (2) posterior view; (3) bilateral lateral views; (4) bilateral anterolateral views; (5) supine view.

The anthropometric measurements are obtained by a skilled, certified orthotist using a sliding mediolateral (M/L) gauge and a flexible tape measure. The measurements are taken up against the skin, with the patient's shirt removed, for increased accuracy. A total of 3 measurements are recorded, which include circumference, M/L diameter, and an A/P diameter at the apex of the prominence. Measurements are taken consistently throughout the course of treatment to quantify correction and clarify the relationship between growth parameters and the response to the orthosis. A tracking form is utilized to follow progress during the treatment process ( Table 1 ).

Fit and Follow-Up

The PC orthosis is fit by a certified orthotist and the patient is educated on adequate tightening of the ratchets to systematically increase pressure throughout treatment. A break-in schedule is recommended initially, in order for the patient to gradually adapt to the pressures of the orthosis. A typical break-in schedule is as follows:

Day 1: (1 hour): Wear for 30 min, then another 30 minutes later in the day. 
Day 2: (2 hours): Wear for 1 hour, then another hour later in the day. 
Day 3: (4 hours): Wear for 2 hours, then another 2 hours later in the day. 
Day 4: (12 hours): Wear for 4 hours during the day, and then to bed (8 hours). 
Day 5: (14 hours): Wear for 6 hours during the day, and then to bed (8 hours). 
Day 6: (16 hours +): Wear for 8+ hours during the day, and then to bed.

Full-time hours range between 16-20 hours per day; with nighttime hours satisfying part of the required time. The orthosis is not allowed to be worn during any strenuous, physical activities, or taken into the shower/bath. Typically, the orthosis is worn full-time for the first 3-12 months or until significant correction has occurred. Some of our patients that choose to wear the orthosis longer (18+ hours/day), had a quicker response to treatment, typically with significant correction in the first 3-6 months. Once full correction has occurred, wear-time can be reduced to 12-14 hours per day until at least 3 months of maintained correction is observed. After 3 months, wear-time can be decreased to just nighttime use (8 hours/day) until the end of treatment; this is the "maintenance" period. The patient must be watchful, as recurrence may occur when wearing the orthosis for less than 14 hours per day.

The patient follows-up with their referring doctor and orthotist frequently within the first couple of months, in order to closely monitor and track the rapid changes and improvement that commonly occur within the first 3 months of compliant treatment. 4, 7 Follow-up occurs with the orthotist 4 weeks post-fit, then again in 4-6 weeks, and then every 3 months to ensure proper fit of the orthosis, address any problems or concerns with protocol, monitor compliance, and track physical changes. The patient also needs to have regular follow-ups with their doctor. Commonly, the patient will follow-up with their doctor 2 weeks post-fit, then again in 6 weeks, and then every 6 months. Orthotic treatment duration is on average for 24 months, or until linear growth ceases. 7, 17

Conclusion

Utilizing an orthosis to treat PC has had gradual recognition in the last 10 years, and in recent years, many doctors are considering it as a first-line treatment for PC. 12 The orthosis has proven to be a safe and effective way to provide favorable outcomes with the possibility to avoid surgical options or having to live with the deformity. In addition, the success of the orthosis increases if the following factors are present; chondrogladiolar PC type, ribcage flexibility, early intervention, and compliancy. However, it is patient compliance that is the single most important factor in achieving optimal results with the orthosis. If adequate, full-time hours are not applied during treatment, the deformity has the opportunity to progress and orthotic treatment becomes ineffective. Therefore, it is crucial for the patient and family to understand the importance of compliancy in order for orthotic treatment to be productive.

TABLE 1: Pectus Carinatum Tracking Form

Patient Name: DOB: Physician:
Date Reason for Visit Age Height Weight Family Hx Date 1 st Noted Type Flexibility Symptoms Hours/Day Circum. @ Apex A/P @ APex M/L @ Apex Comments
                             
                             
                             
                             

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