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MMCTS (January 2, 2007). doi:10.1510/mmcts.2004.000315
Copyright © 2007 European Association for Cardio-thoracic Surgery

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Procedure


Chest wall surgery: Nuss technique for repair of pectus excavatum in adults

Laureano Molins*, Juan J. Fibla, Javier Perez and Gonzalo Vidal

Thoracic Surgery, Hospital Sagrat Cor, Barcelona University, Viladomat 288, 08029 Barcelona, Spain

* Corresponding author: * Tel.: +34-934-948922; fax: +34-934-052641 E-mail: lauremolins{at}comb.es; lmolins{at}hscor.com


   Summary
Top
 Summary
Introduction
 Surgical technique
 Postoperative treatment
 Results
 Discussion
 References
 
Pectus excavatum is a congenital deformity of the thoracic wall consisting in the concavity of the sternum and of the costal cartilages. The standard operative treatment of pectus excavatum has been the Ravitch's technique that requires the exposition of the thorax's anterior region with resection of the costal cartilages affected bilaterally, the performance of a cross sternal osteotomy with the placing of a stabiliser, and the development of muscular flaps. The conviction that the correction of the pectus excavatum is essentially aesthetic led Donald Nuss to put forward a new procedure by means of minimally-invasive surgery based on the skeleton's malleability and remodelling capacity applied to the thorax. Thus he designed a technique consisting of a retrosternal steel bar that would modify the concavity of the sternum while maintaining the contour of the reformed thorax, all done by means of two small incisions on each side of the thorax with the help of the thoracoscope. The maintenance of the bar for 2 or 3 years, and its posterior removal, results in 95% of the cases in a corrected thorax with a considerable aesthetic improvement.

Key Words: Pectus excavatum • Minimally invasive surgery • Videothoracoscopy • Thorax abnormalities


   Introduction
Top
 Summary
 Introduction
Surgical technique
 Postoperative treatment
 Results
 Discussion
 References
 
Pectus excavatum (PE) is a congenital deformity of the thoracic wall consisting in the concavity of the sternum and of the costal cartilages. It is not known exactly what the mechanism is by which this abnormal growth of the costal cartilage and the bone is produced. There seems to exist a multifactorial etio-pathogeny involving weakness of the parasternal cartilages due to a metabolic disorder. The deformation happens due to mechanical factors derived from breathing or growth. There is a family incidence in up to 35% of the cases and the association of pectus excavatum with Marfan's and/or Poland's condition is a well known one [1] (Photo 1).


Figure 1
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  		Photo 1 Severe pectus excavatum.

 
Its incidence is 1 in 1000 births, and an incidence has been described of even 1/300–400 live births. There is a predominance of the male over the female sex of 3:2. The deformity of the pectus excavatum tends to affect 4–5 ribs on each side of the sternum, with great variability with respect to the mild, moderate or severe condition, and to the symmetry of the defect (Photo 2).


Figure 2
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  		Photo 2 Chest CT of pectus excavatum.

 
The severity of the pectus can be measured by the Haller index, obtained after dividing the side diameter by the anteroposterior diameter. A severe condition is taken to be when it is >3.25 (Normal value: 2.56) [2].

The indication of treatment of the pectus excavatum is eminently aesthetic and because of psychological repercussions, although several authors add to it the severity of the pectus (Haller index >3.25), the existence of a restrictive pattern in the respiratory functional tests, the existence of a prolapse of the mitral valve, cardiac compression or displacement and the documentation of a progression of the deformity [3, 4]

Conservative treatment:

  • Rehabilitation: little influence over the skeleton
  • Orthopaedic: device to compress the costal rims for years

Surgical treatment:

  • Ravitch: resection of the costal cartilages affected bilaterally + cross sternal osteotomy ± stabiliser and muscles flaps
  • Wada: ‘sternal turnover’
  • Nuss: ‘pectus bar’ by VATS

The conservative treatment of the pectus excavatum has not had much success, given the little influence of rehabilitation over the skeleton. The operative treatment of pectus excavatum has been a well established and standardised one ever since Ravitch's publication in 1949 [5] being universally accepted by surgeons as the standard treatment, requiring the exposition of the thorax's anterior region with resection of the costal cartilages affected bilaterally, the performance of a cross sternal osteotomy with the placing of a stabiliser, and the development of muscular flaps. A number of series has been published with acceptable results and a low complication rate [3, 6].

The conviction that the correction of the pectus excavatum is essentially aesthetic led Donald Nuss, a pediatric surgeon in Virginia, USA, to put forward a new procedure by means of minimally-invasive surgery based on the skeleton's malleability and remodelling capacity applied to the thorax [7].


   Surgical technique
Top
 Summary
 Introduction
 Surgical technique
Postoperative treatment
 Results
 Discussion
 References
 
Dr Nuss designed a technique, based on the internal fixation mechanisms that allow orthopaedic surgeons and orthodontists to correct skeletal anomalies such as scoliosis or bad maxillomandibular occlusion, consisting of a retrosternal steel bar – stabilised on the costal grid – that would modify the concavity of the sternum while maintaining the contour of the reformed thorax, all done by means of two small incisions on each side of the thorax with the help of the thoracoscope – which has come to be known as the Nuss technique [7] (Schematic 1).


Figure 1
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  		Schematic 1 Nuss' technique scheme.

 
There is no consensus regarding the age at which this surgery should be offered. In paediatric surgery circles, the age is obviously younger (between 5 and 12 years) than in the series of thoracic surgeons. It would seem logical that the customary aesthetic indication and the possibility of a disproportionate growth of the patient may lead us to think of correction from the age of 14–18 years, although other authors see no greater objection to indicate correction at earlier ages (rib and cartilage structures are more malleable) or even in adult patients [8, 9]. If functions of the heart and lungs are impaired the best timing for a surgical intervention is based on the clinical findings of the individual patient. The optimal cosmetic result can be achieved in most symmetric deformities, while in eccentric ones there is the possibility not to achieve a completely optimal result [10]. It is a basic requirement for all patients strongly demanding surgery that they are – in view of their mental development stage – capable of understanding their decision (Photo 3).


Figure 3
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  		Photo 3 Severe PE in a 28-year-old female.

 
Preoperative examinations:

  1. Complete history and examination
  2. X-ray of the chest (p.a. and lateral)
  3. Complete cardiologic examination with ECG
  4. CT-scan of the chest (visualisation of the chest organs)
  5. Spirometry (possibly)

To date, the implant set of the pectus bar (Photo 4) is supplied by two companies: Walter Lorenz Surgical and Medxpert.


Figure 4
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  		Photo 4 Pectus bar instruments. Pectus bar bender, pectus bar clamp, pectus bar introducer (18.8'', 20''), pectus bar plate flipper. Templates: 7–17'' (17.8–43.2 cm).

 
The patient is in the supine position with both arms abducted and the deepest point of the pectus excavatum is marked. The length of the pectus bar is determined by the distance from the right to left mid-axillary line minus 1–2 cm, as it will be under the sternum. It may be bent into the desired shape already before sterilisation or during the surgery, using the template as a model (Schematic 2, Photos 5 and 6).


Figure 2
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  		Schematic 2 Measurement of the chest.

 

Figure 5
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  		Photo 5 Bending of the pectus bar.

 

Figure 6
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  		Photo 6 Using the template as a model.

 
An epidural catheter is inserted pre-operatively to provide postoperative pain control. Under general anaesthesia, a double lumen endotracheal will provide unilateral lung ventilation. Before prep and drape, the planned incisions are marked: in the mid-axillary lines left and right (for the stabiliser plate) and in the top of the pectus ridge on each side (to enter into the chest), following the line through the deepest point of the chest to both sides, remaining always in the same intercostal space (Video 1).


Figure 1
Click on image to view video		 Video 1 Epidural catheter; marking planned incisions.
 
Incisions of 2.5 cm as marked before bilaterally are performed and a skin tunnel from both incisions towards the marked point at the top of the pectus ridge on each side are raised. After collapsing the right lung, the videothoracoscope is inserted 1–2 intercostal spaces below the right lateral thoracic wall skin incision (Video 2, Schematic 3).


Figure 2
Click on image to view video		 Video 2 Incisions, skin tunnel and insertion of videothoracoscope.
 

Figure 3
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  		Schematic 3 Incisions and thoracoscope positioning.

 
A thorough inspection is carried out checking the pectus excavatum, the lung, the mediastinum, the phrenic nerve, making sure that the external markings line up well with the internal anatomy. By retraction of the right skin incision anteriorly, the point at the top of the pectus ridge is reached subcutaneously, and a clamp is inserted through the previously selected intercostal space, under thoracoscopic control. Following, the introducer is inserted positioning it below the pectus. If the diaphragm limits the view of the pectus the thorax can be inflated with gas (Video 3).


Figure 3
Click on image to view video		 Video 3 Insertion of a clamp and the introducer through the point at the top of the pectus ridge.
 
Then the introducer is positioned under the deepest part of the sternum, with the point always facing anteriorly and in contact with the sternum, lifting up the pectus. With a slight lateral movement, the introducer is advanced slowly across the mediastinum in the correct direction, looking for the tip on the opposite side (Schematic 4, Video 4).


Figure 4
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  		Schematic 4 Introducer advancing across the mediastinum.

 

Figure 4
Click on image to view video		 Video 4 Introducer advancing across the mediastinum in the correct direction.
 
The tip of the introducer emerges on the opposite side at the marked spot (left) under the skin, just medial of the ridge of pectus through the same intercostal space (Video 5).


Figure 5
Click on image to view video		 Video 5 Left side vision. Final step of the introducer emerging on the left side.
 
An umbilical tape is tied and pulled through the tunnel by the introducer from the left to the right side, to use it as a guidance for the pectus bar (Schematic 5).


Figure 5
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  		Schematic 5 Pulling the umbilical tape.

 
The umbilical tape is tied to the pectus bar. It is introduced from the right side and pulled to the left side on the attached umbilical tape under the sternum, with the convexity facing posteriorly (Video 6).


Figure 6
Click on image to view video		 Video 6 Inserting the pectus bar.
 
With the pectus bar in position, it is turned over with the flipper raising the sternum and the anterior chest wall into the desired position (Video 7).


Figure 7
Click on image to view video		 Video 7 Turn over of the pectus bar.
 
The distal ends of the pectus bar must be close to both lateral sides of the chest wall. If they are not, bend the distal ends slightly to the inside. Stabilisation of the bar is essential for success. The pectus bar is secured to the chest to avoid bar displacement with two stabiliser plates which are sutured together with no. 3 wire, heavy non-absorbable sutures or, more recently, with a metal bar lock introduced in a distal hole (Video 8 and Photo 7).


Figure 8
Click on image to view video		 Video 8 Bending the bar and fixation with stabiliser plates and a metal bar lock.
 

Figure 7
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  		Photo 7 Stabiliser secured with a metal bar lock introduced in a distal hole.

 
The stabiliser is secured to the lateral chest wall muscles with many sutures through the holes. The bar can also be reinforced by a suture around the rib (Video 9).


Figure 9
Click on image to view video		 Video 9 Suturing the stabiliser.
 
Prior to closing the chest, re-inspection of the chest with the thoracoscope is done to ensure that there is no bleeding or injury to the pericardium, lungs, etc. Two chest tubes are inserted into both cavities prior to re-expansion of both lungs under direct vision. Lateral incisions are closed in layers with subcuticular suture with an excellent final result (Photo 8).


Figure 8
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  		Photo 8 Preop and postop results.

 

   Postoperative treatment
Top
 Summary
 Introduction
 Surgical technique
 Postoperative treatment
Results
 Discussion
 References
 
The two chest tubes are removed with the patient awake after chest X-ray with complete lung re-expansion and no air leak. Postoperative pain control with a mixture of dilute local anaesthetic bupivacaine and narcotic fentanyl infused slowly (Photos 9 and 10).


Figure 9
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  		Photo 9 P-A chest X-ray on the first postoperative day with correct bar position.

 

Figure 10
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  		Photo 10 Lateral chest X-ray on the first postoperative day with correct bar position.

 
Removal of the pectus bar
In adults the bar should not be removed earlier than 2.5 years and it would be better to leave it in place for up to 3 years.


   Results
Top
 Summary
 Introduction
 Surgical technique
 Postoperative treatment
 Results
Discussion
 References
 
Here we present the experience of Donald Nuss' own technique ([11] and personal communication, Barcelona 2002). See Tables 1 and 2.


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  		Table 1 Initial results

 

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  		Table 2 Long-term results

 

   Discussion
Top
 Summary
 Introduction
 Surgical technique
 Postoperative treatment
 Results
 Discussion
References
 
Several publications are available concerning the beneficial results of this minimally-invasive surgical procedure in the quality of life of the children and adult patients [12]. Moreover, several recent manuscripts assess the improvement in cardiovascular and pulmonary function after Nuss correction of pectus excavatum [13].

Several case-report complications with the procedure have been published, being in adults more frequent than in the paediatric population. Park, Lee and Lee from South Korea [10] have published the complications associated with the Nuss procedure in the second largest series of 335 patients, with analysis of risk factors.

Displacement of the stabiliser and shifting of the bar are the most frequent complications observed [4, 11, 14]. The stabiliser can be secured with a wire-fixation or with a metal bar lock introduced in a distal hole (Photos 11, 12, 13 and 14).


Figure 11
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  		Photo 11 Pectus bar displacement.

 

Figure 12
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  		Photo 12 Prevention of stabiliser displacement: wire-fixation.

 

Figure 13
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  		Photo 13 Prevention of stabiliser displacement: metal bar lock (I).

 

Figure 14
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  		Photo 14 Prevention of stabiliser displacement: metal bar lock (II).

 
Hebra et al. [15] published a simple technique for preventing bar displacement, with a suture around the bar and underlying rib. The use of the lateral stabiliser, wired or locked, and adding the suture around the rib has decreased the incidence of bar shifts requiring revision [4, 11, 14].

There are some more technical aspects to comment on. The incidence of pneumothorax published is quite high in the paediatric series. In my opinion this can be avoided by using a chest drain on suction for a while after the procedure.

Some authors recommend the extrapleural position of the bar trying to minimise pleural and pericardial effusion, pulmonary bar adhesions, pneumothorax and pain [16]. Also, a submuscular rather than subcutaneous position of the bar and stabilisers has been reported with the intention of reducing the pain and to have less wound discomfort [17]. We and others think that the extrapleural approach offers no advantages to the intrapleural, and the subcutaneous position of the bar is good enough as the submuscular position has created an intense bone formation around the bar at removal [18, 19]. To eliminate the risk of cardiothoracic injury the left thoracoscopy can be used as well as an Endo-kittner or a vacuum chest wall lifter, to facilitate the substernal dissection [20].

During the removal of the pectus bar, a massive haemorrhage occurred due to erosion of a pulmonary vessel [21]. In my personal experience an erosion of an intercostal artery during the extraction of a bar caused a haemorrhage of 1500 cc, requiring a larger opening of the lateral incision to stop it. If there are difficulties in the bar removal, the use of the thoracoscope is a safe way to evaluate the problem.

There are three series comparing the Nuss and Ravitch techniques [22, 23, 24]. Both procedures provide excellent clinical results with less operative time and hospitalisation and more complications in the Nuss procedure. On the other hand, as compared with the open repair, Nuss technique was associated with a 27% lower overall cost of hospitalisation (P<0.05) [24]. Technical operative details and surgeon's experience are essential for optimal results using both techniques.



   References
Top
 Summary
 Introduction
 Surgical technique
 Postoperative treatment
 Results
 Discussion
 References
 

  1. Hebra A. Minimally invasive pectus surgery. Chest Surg Clin N Am 2000;10:329–339.[Medline]
  2. Haller JA Jr, Shermeta DW, Tepas JJ, Bittner HR, Golladay ES. Correction of pectus excavatum without prostheses or splints: objective measurement of severity and management of asymmetrical deformities. Ann Thorac Surg 1978;26:73–79.[Abstract]
  3. Ravitch MM. Pectus Excavatum. Congenital deformities of the chest wall and their operative correction 1977, WB Saunders.
  4. Nuss D. Recent experiences with minimally invasive pectus excavatum repair "Nuss procedure". Jpn J Thorac Cardiovasc Surg 2005;53:338–344.[Medline]
  5. Ravitch MM. The operative treatment of pectus excavatum. Ann Surg 1949;122:429–444.
  6. Davis JT, Weinstein S. Repair of the pectus deformity: results of the Ravitch approach in the current era. Ann Thorac Surg 2004;78:421–426.[Abstract/Free Full Text]
  7. Nuss D, Kelly RE Jr, Croitoru DP, Katz ME. A 10-year review of a minimally invasive technique for the correction of pectus excavatum. J Pediatr Surg 1998;33:545–552.[CrossRef][Medline]
  8. Croitoru DP, Kelly RE Jr, Goretsky MJ, Lawson ML, Swoveland B, Nuss D. Experience and modification update for the minimally invasive Nuss technique for pectus excavatum repair in 303 patients. J Pediatr Surg 2002;37:437–445.[CrossRef][Medline]
  9. Coln D, Gunning T, Ramsay M, Swygert T, Vera R. Early experience with the Nuss minimally invasive correction of pectus excavatum in adults. World J Surg 2002;26:1217–1221.[CrossRef][Medline]
  10. Park HJ, Lee SY, Lee CS. Complications associated with the Nuss procedure: analysis of risk factors and suggested measures for prevention of complications. J Pediatr Surg 2004;39:391–395.[CrossRef][Medline]
  11. Nuss D, Croitoru DP, Kelly RE Jr, Goretsky MJ, Nuss KJ, Gustin TS. Review and discussion of the complications of minimally invasive pectus excavatum repair. Eur J Pediatr Surg 2002;12:230–234.[CrossRef][Medline]
  12. Krasopoulos G, Dusmet M, Ladas G, Goldstraw P. Nuss procedure improves the quality of life in young male adults with pectus excavatum deformity. Eur J Cardiothorac Surg 2006;29:1–5.[Abstract/Free Full Text]
  13. Lawson ML, Mellins RB, Tabangin M, Kelly RE Jr, Croitoru DP, Goretsky MJ, Nuss D. Impact of pectus excavatum on pulmonary function before and after repair with the Nuss procedure. J Pediatr Surg 2005;40:174–180.[CrossRef][Medline]
  14. Park HJ, Lee SY, Lee CS, Youm W, Lee KR. The Nuss procedure for pectus excavatum: evolution of techniques and early results on 322 patients. Ann Thorac Surg 2004;77:289–295.[Abstract/Free Full Text]
  15. Hebra A, Gauderer MW, Tagge EP, Adamson WT, Othersen HB Jr. A simple technique for preventing bar displacement with the Nuss repair of pectus excavatum. J Pediatr Surg 2001;36:1266–1268.[CrossRef][Medline]
  16. Hernandez H, Varela A, Cordoba M, Madrigal L, Artes M. Videothoracoscopic extrapleural insertion of Walter Lorenz surgical bar for pectus excavatum. J Thorac Cardiovasc Surg 2003;126:2081–2082.[Free Full Text]
  17. Schaarschmidt K, Kolberg-Schwerdt A, Lempe M, Schlesinger F, Bunke K, Strauss J. Extrapleural, submuscular bars placed by bilateral thoracoscopy – a new improvement in modified Nuss funnel chest repair. J Pediatr Surg 2005;40:1407–1410.[CrossRef][Medline]
  18. Molins L, Simon C, Vidal G. Minimally invasive correction of pectus excavatum by video-assisted thoracoscopy. Arch Bronconeumol 2003;39:240.[CrossRef][Medline]
  19. Ostlie DJ, Marosky JK, Spilde TL, Snyder CL, St Peter SD, Gittes GK, Sharp RJ. Evaluation of pectus bar position and osseous bone formation. J Pediatr Surg 2003;38:953–956.[CrossRef][Medline]
  20. Schier F, Bahr M, Klobe E. The vacuum chest wall lifter: an innovative, nonsurgical addition to the management of pectus excavatum. J Pediatr Surg 2005;40:496–500.[CrossRef][Medline]
  21. Leonhardt J, Kubler JF, Feiter J, Ure BM, Petersen C. Complications of the minimally invasive repair of pectus excavatum. J Pediatr Surg 2005;40:e7–9.[Medline]
  22. Boehm RA, Muensterer OJ, Till H. Comparing minimally invasive funnel chest repair versus the conventional technique: an outcome analysis in children. Plast Reconstr Surg 2004;114:668–673; discussion 674–675.[CrossRef][Medline]
  23. Fonkalsrud EW, Beanes S, Hebra A, Adamson W, Tagge E. Comparison of minimally invasive and modified Ravitch pectus excavatum repair. J Pediatr Surg 2002;37:413–417.[CrossRef][Medline]
  24. Inge TH, Owings E, Blewett CJ, Baldwin CE, Cain WS, Hardin W, Georgeson KE. Reduced hospitalization cost for patients with pectus excavatum treated using minimally invasive surgery. Surg Endosc 2003;17:1609–1613.[CrossRef][Medline]



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