Research Paper:

Diagnosis and Treatment of Pectus Excavatum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pawan Mukkar

KINE 4900.03

November 25, 2003

 

PECTUS EXCAVATUM: Diagnosis and Non-Surgical Treatment

Pectus Excavatum (PE) is a congenital disorder in which there is an abnormal depression on the lower end of the sternum and its attached costal cartilages. (Cherniack, 1983)  It is the most common form of chest deformity, accounting for almost 90% of all chest wall defects, and is diagnosed in one in every 1,000 births. (Crump, 1992), (Swoveland et al, 2001).  Ravitch (1949) was the first to publish a description of the disorder.  He described it as having a depressed sternum, rounded shoulders, slight dorsal kyphosis, prominent potbelly, and abnormal retraction of the sternum on deep inspiration.  (Actis Dato et al, 1995), (Crump, 1992) 

Male patients are affected more than females at a 4:1 ratio with an unproven genetic predisposition. PE reaches maximal depression by the mid teenage years, thus marking the end of risk-free surgical intervention. (Actis Dato et al, 1995), (Swoveland et al, 2001). The anteroposterior diameter of the chest cage is reduced and the chest cage is longer and narrower than normal. (Fig. 1)  Since the cartilage and bony structure of an infant’s chest cage are softer and more mobile than in adults, the depression becomes fixed as the child develops. 

Pathophysiology

            Pectus Excavatum is a progressive deformity, which may or may not result in significant respiratory disturbance, depending on its grading. (Actis Dato et cal, 1995)  In severe forms, distortion of the heart and lungs produce symptoms of dyspnea and palpitations.  There is an abnormal expenditure of energy because of an increased oxygen uptake due to abnormal chest architecture.  Intra-thoracic restriction and a mild decrease in total lung capacity and vital capacity, because of impaired left chest expansion, are often seen, as well as an increase in residual volume (Table 4).  (Crawley et al, 1999), (Actis Dato et al, 1995), (Theerthakarai, 2001) 

Electrocardiograms show an axis deviation and lateral displacement of the heart, a right bundle block due to compression of the right heart, premature right ventricular contraction, and tachycardia. (Actis Dato et al, 1995), (Crump, 1992)  Pulmonary hypertension is very prominent with PE patients. (Theerthakarai, 2001)  Also because of the compression on the heart, the right atrium and ventricle become dilated and there is decreased systolic function and diastolic filling. (Theerthakarai, 2001)  This cardiopulmonary dysfunction results in a decreased stroke volume and cardiac output with upright exercise.  (Crump, 1992)

Upon moderate exertion dyspnea is common.  This shortness of breath and accompanied easy fatigability is a staple of the decreased anteroposterior diameter of the chest and compression of the lungs. (Theerthakarai, 2001)  Inability to take deep breaths, wheezing upon expiration, and frequent respiratory tract infections are also often found to be common among PE patients. (Schneiderman, 2003), (Morshuis et cal, 1994)  With most of the sternal compression falling on the heart, it is often seen that improvement in pulmonary function may not be due to improved lung capacity, but due to cardiorespiratory function, by surgical or non-surgical treatment.  (Morshuis et al, 1994)

Surgical Intervention

Pectus Excavatum has been successfully corrected with various surgical treatments.  To date, there are approximately 30 variations available.  Of these 30, five are the most commonly used.  The newest, and most increasingly common, is the minimally-invasive Nuss Procedure, developed by Dr. Donald Nuss. (Swoveland et al, 2001)  The Nuss procedure uses a curved surgical steel bar placed under the sternum to pop out the depression.  In another very common technique, the sternum is surgically removed from its depression and repositioned anteriorly by sternal osteotomy.  With another, a brace is used to pull the sternum anteriorly, and then is removed after 6 weeks.  Sternal turnover, in which the depressed sternum is removed, turned over, then surgically stabilized, is less common.  Silastic implants can also be used, but only in severe adult cases and as a last resort. (Crump, 1992)

Endobronchial stenting, similar to the Nuss procedure, has been clinically proven to improve conditions related to spirometry two weeks after placement (Table 1). (Crawley et al, 1999)  A 26% increase in [FEV.sub.1] and a 14 L/min increase in MVV were observed.  Other studies also show improvements in [FEV.sub.1], MVV and VC with stent surgical repair. (Table 2) (Actis Dato et al, 1995) 

Although subjective improvements in exercise tolerance and dyspnea often are noted after surgery, pulmonary function improvement is infrequent and modest.  Many people have even exhibited a decrease in pulmonary function after surgery. (Morshuis et al, 1994)  Scarring from surgery can limit thoracic expansion, especially if the procedure is too extensive or is preformed pre-complete chest cage development. (Schneiderman, 2003)  Certain surgical techniques are proven to subjectively improve lung and heart function in pectus excavatum.  Most patients to receive surgical intervention, however, are young, and since there have not been any controlled studies monitoring natural growth versus surgical repair, it cannot be said for certain that surgery would be optimal for all PE patients.  Pectus Excavatum deformities usually become more severe during adolescent growth years and remain the same after the age of 18 and throughout life. (Swoveland et al, 2001)

CASE STUDY

Samuel is a 27 year old male diagnosed with the chest wall deformity Pectus Excavatum with a ‘moderate’ rating of 3.0 on the Haller Index.  Sam was diagnosed with PE when he was 6 months old, but never had any surgical intervention.  His PE depression became significantly worse when he was 14 years old.  Although he experienced some psychological distress while growing up, emotional support, and later, spousal support reserved his decision for invasive corrective surgery.  Sam is modestly unfit because of his hesitance to exercise.  He experiences dyspnea, wheezing, chest pain and increased respiration when walking up a flight of stairs or running more than a ¼ mile.  His appearance disturbs him (fig. 1), but his reasons for his non-surgical correction of his PE are related to his inability to perform daily tasks, and not cosmetic reasons. 

Clinical Assessment

History (Lifestyle and Medical):

• Psychological assessment (questionnaire; assessment of cosmetic reasons for corrective exercise vs. fitness and lifestyle reasons).  Sam does not have cosmetic reasons for correction.
• Familial presence of PE or related chest deformity.  No history of PE in Samuel’s family.
• Familial presence of cardiopulmonary or cardiorespiratory disorders.  No history of either.
• Lifestyle habits: i.e. Smoking, diet, physical activity.  Sam does not smoke, his diet is relatively good, producing no health risks.  He has been unable to participate in very much physical activity requiring exertion more than 60% [VO.sub.2]max.  Often it is difficult for him to climb more than one flight or stairs or run more than a ¼ mile.  Sam loves fast-paced sports, but finds it difficult to participate because of his dyspnea. 

Physical Assessment (initial):

• Height, weight, body mass index, blood pressure, resting heart rate, Haller Index number (Table 3), chest measurements and angles, shoulder and neck angles (fig. 3). 
• Exercise limitations (with Exercise Induced Stress Test; discussed below)
• Chest X-Rays and a CT Scan are done (Fig. 5)
• Both tests show heart displacement and describe the accurate measurements of the chest depression. The displaced heart is very visible in Samuel’s CT scan (Fig. 4)
• Haller Index – divide transverse measurement by the anteroposterior measurement of the chest.  The greater the depression, the greater the number will be.  An index greater than 3.5 is considered “Severe”.  Sam’s Haller Index number was 3.0, putting him in the “Moderate” category.

• Echocardiogram

o       To check for heart changes and heart valve problems

o       It is also often done to find distortion of the heart chambers and aorta. In Sam’s case the pulmonary hypertension. 

• Pulmonary Function Tests (Pre-Exercise Induced Stress Test) (Table 4)

o       Spirometry  and measurements of [FEV.sub.1], MVV, TLC, VC and RV are taken.

• Exercise Induced Stress Test & Electrocardiogram

o       The Naughton Protocol is used in conjunction with the Borg Scale Rating of Perceived Exertion.  This protocol is ideal for clinical populations using a graded treadmill exercise test (for ideal upright posture of the PE patient).  The speed stays constant at 2.0 miles per hour, but the treadmill slope is raised by 3.5% at the end of each two-minute increment.  The testing is stopped if the systolic blood pressure drops more than 10mmHg from baseline, the patient experiences chest pain, overwhelming dyspnea, difficulty monitoring ECG, tachycardia and desire to stop.  An estimate of the patient’s [VO.sub.2]max is taken from the standard data.  Sam was able to work at 2.0 miles/hour for a total for 10 minutes up to an incline of 10.5%.  His work rate was at 5 metabolic equivalents, with an estimated [VO.sub.2] at about 18ml[O.sub.2]/kg/min when he stopped the test due to dyspnea.  Heart rate, blood pressure and respiration rate are also monitored.

o       ECG monitoring takes place with the stress test in order to show the strain on the right heart, i.e. systolic and diastolic function.  Sam’s ECG showed sinus tachycardia at rest, right-axis deviation, and right atrial enlargement. (Theerthakarai, 2001)

• Pulmonary Function Tests are taken again after the Exercise Induced Stress Test in order to assess whether or not there is a change in lung function with exercise.

Exercise Protocol Designed for Samuel

Patients with PE are encouraged to remain physically active.  They generally remain in better health and functioning ability than those who do not. (Cherniack, 1983) By exercising breathing control, patients can compensate for lack of lung volume by the extensive movements of the diaphragm. (Fig. 6)  Poor posture can cause and/or worsen PE.  Therefore it is essential to correct Sam’s posture.  Correction can be done by application of external force (i.e. another person) or by orthopedic support vests or corsets.  The corset allows contraction of lower ribs to proper position, and forces expansion of lungs up into the chest.  It’s also important to push shoulders back as well as the neck, to help protrude the sternum more.  Exercises of posture include Isometrics to straighten the spine.  The sternocostal and costovertebral cartilage strain and reform correct shape and position, and thus the orientation of the ribs will change.  The muscles in the upper back, abdomen and ribcage will straighten the spine, and the brace will limit the range of motion. 

Exercise Protocol for Samuel:

The following regimen would be recommended twice per day, every day; once upon waking in the morning, and once before going to bed.  Each session should take approximately 10 minutes, therefore Sam would be active for about 20 minutes everyday. 

Stretch Exercises:

1. Shoulder rolls (front and back) – creating military posture (2 set of 10 repetitions)
2. Side-Arm stretch – stretching one arm over the head (holding each stretch for about 20 seconds without ballistics)
3. Neck Stretch – Lying on back, touch ear to shoulder.  This will assist in correcting asymmetry of neck length  (hold stretch for 20 seconds)
4. Back Arching – Lying on back, will push sternum outward (hold stretch for 30 seconds, breathing deeply)

Posture Exercises:

1. Pushups – will strengthen pectorals and abdominal muscles.  (goal is to do 25; work on pushups incrementally)
2. Sacrospinalis muscle strengthening – exercise to strengthen the lower back.  This includes arched-leg lifts, and upper back push ups.  Sam should to 1 set of 10 reps each. 
3. Sit-ups are good exercises to strengthen his abdominal muscles.  With someone holding his feet, Sam would do a sit-up halfway up (injury is possible going all the way up) and then back down.  (the goal is to do 30 sit-ups, increase incrementally)

Aerobic Exercise:

1. In order to work on lung compliance, Sam should run on a treadmill to ensure upright position during exercise.  His regimen would include running 3X/week, starting at 10 minutes, at 50% of his [VO.sub.2]max.  Graded incline would be best, starting at 0% incline increasing 2% every 2 minutes.  Every week, Sam should increase distance by 1 minute.  With the posture stretching and exercises, he will find that his ability to exercise longer will increase.
2. Along with running, it is recommended that Sam plays sports.  Soccer or basketball would be ideal to keep him motivated to be active, and Tai Ch’I is an excellent way to utilize deep breathing exercise while working on muscle stabilization. 

Moderate chest workouts are acceptable, but building upper body muscles is not recommended because of increasing pressure onto the sunken sternum, thus compromising lung function further.  Follow up should consist of chest measurements and should occur every month until desired results are met, usually about 3-4 months.    

Conclusion

            Although it appears to be quite a devastating ventilatory disorder, Pectus Excavatum seems to produce more cardiorespiratory defects rather than cardiopulmonary ones. (Malek et al, 2003) It is essential that optimal testing be done to determine the severity of the disorder before proceeding with surgical or non-surgical correction.  Research is continuing on efficiency of exercise protocols as a replacement for severe PE, while mild to moderate PE symptoms can successfully be alleviated by the use of isometric exercises and graded aerobic exercise. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

APPENDIX A:

Tables and Figures

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tables and Figures

 

Fig. 1: Example of Patient X with

Advanced and severe pectus excava

-tum pre- treatment

 

 

Test                                                                 Pre Stenting                Post Stenting

 

FVC (% predicted)                                          2.84 (49%)                  3.01 (52%)

[FEV.sub.1] (% predicted)                               1.79 (37%)                  2.25 (46%)

[FEV.sub.1]/FVC                                            0.63                             0.75

MVV L/min                                                      79                                93

[VO.sub.2] Max ml/min (% predicted)  2432 (77%)                 2480 (79%)

Pa[CO.sub.2] mmHg (peak exercise)               49                                42

 

Table 1: Spirometry improvement post-endobronchial stenting (Crawley et al, 1999)

 

 

 

 

Test                             Preoperative               Postoperative

 

VC (L)                         2.66 [+ or -] .39           4.38 [+ or -] .27

[FEV.sub.1] (L/s)         2.62 [+ or -] .35           3.40 [+ or -] .23

MVV (L/min)               78.64 [+ or -] 3.8         135.6 [+ or -] 4.18

 

Table 2: Pulmonary Function Assessment Before and After Surgery in 16 Patients who

  had Surgery Because of Functional Respiratory Insufficiency (Actis Dato et al, 1995)

 

 

Measurement                                     Value                          Discussion

 

Height (inches)                          70                   

Weight (lbs)                                          150                                                                 

BMI                                                     21.5                             BMI is on low side of normal

range

Blood Pressure (mmHg)                       102/80                         systolic slightly decreased

due to reduced SV and CO

RHR (b/min)                                         103                              sinus tachycardia evident

through resting ECG

Haller Index                                          3.0                               Moderate rating (3.5=severe)

Resting Resp. Rate (br/min)                  24

 

Table 3: Samuel’s pre-exercise program physical assessment. 

 

Fig. 2: Samuel’s physical assessment                                     Fig. 3: Samuel’s CT Scan showing

                         displacement of heart and chest 

                         compression              

 

Variables                                           Results                         % Predicted

 

FVC, L                                               0.72                              19

[FEV.sub.1], L                                    0.72                              24

[FEV.sub.1]/FVC, %                          100                              

TLC, L                                               1.76                              35       

RV, L                                                 1.04                              108

FRC, L                                               1.34                              48

ERV, L                                               0.14

 

Table 4: Samuel’s Pulmonary Function Studies.  The residual volume of people with

              Pectus Excavatum is often seen to be greater than predicted.  (Theerthakarai, 2001)

 

 

Fig. 4: Patient M.B. Chest CT showing severe asymmetric pectus excavatum (CT index 8.5)

            with severe cardiac compression and displacement, and pulmonary atelectasis.

 

   

                                             

 

Fig. 5: Breathing exercises done post-surgery.  These breathing exercises can also be  done during exercise protocol in non-surgical treatment for pectus excavatum. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

APPENDIX B

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

 

Actis Dato, G.M., et al. (1995). Correction of Pectus Excavatum with a Self-Retaining Seagull Wing Prosthesis: Long-Term Follow-Up.  Chest, 107, p303(4).  (6)

 

Cherniack and Cherniack. (1983).  Respiration in Health and Disease: 3^rd Ed. (355, 385).  Philedelphia: W.B. Saunder’s and Company.  

 

Crawley, E.A., Hnatiuk, O.W., Fitzpatrick, T.M. (1999).  Endobronchial Stenting for Pectus Excavatum Associated Symptomatic Airway Compression.  Chest, 116, p395S.

 

Crump, H.W. (1992). Pectus Excavatum. American Family Physician, 46, p173(7).

 

Malek, M.H, et al. (2003).  Ventilatory and Cardiovascular Responses to Exercise in Patients with Pectus Excavatum.  Chest, 124, p870(12).

 

Morshuis, W, Folgering, H, Barentsz, J, vanLier, H, Lacquet, L. (1994). Pulmonary Function before Surgery for Pectus Excavatum and at long-term Follow-up.  Chest, 105, p1646(7).

 

Schneiderman, H. (2003).  What’s your Diagnosis?  Consultant, 43, p. 109(3).

 

Swoveland, B., Medrick, C., Kirsh, M., Thompson, K.G., Nuss, D. (2001).  The Nuss Procedure for Pectus Excavatum Correction.  AORN Journal, 74, p828(13).

 

Theerthakarai, R, El-Halees, W, Javadpoor, S, Anees Khan, M. (2001). Severe Pectus Excavatum Associated With Cor Pulmonale and Chronic Respiratory Acidosis in a Young Woman.  Chest, 119, p1957.