Instructions for Candidate

OSPHE Question: minimally invasive placement of pectus bar

Instructions for Candidate

You have 8 minutes to prepare for this OSPHE.

The station is designed to assess all of the OSPHE competencies.

Scenario

You are a public health trainee at Citywide PCT. The Chief Executive has received a letter from the parent of a 9 year old boy with a congenital deformity of the sternum and anterior chest wall called ‘Pectus excavatum’ or ‘funnel chest’. The child’s paediatrician has recommended correction of the condition using a new ‘Nuss procedure’ which is minimally invasive, instead of the routine open surgical method, known as the Ravitch procedure. The parent wants the child to have the new Nuss procedure, but wants to understand why it is not normally available, and has requested a meeting. The Director of Public Health is on three week’s holiday and the Chief Executive has asked you to meet the parent.

The National Institute of Clinical Excellence has reviewed the new procedure and issued an Interventional Procedure Guidance, which recommends that the procedure is only used with special arrangements for consent, audit or research.

Your task:

Your task is to:

Check the parent’s understanding about why the procedure is done and what it involves

Explain the role of NICE when new procedures are developed

Explain the risks and benefits of open and minimally invasive procedures, including the complications

Ensure the parent understands issues of consent and why the procedure is part of a research or audit study.

To help you prepare your briefing pack contains:

The NICE Interventional Procedure Guidance 3 for ‘Minimally invasive placement of pectus bar

Interventional Procedure Overview of Minimally Invasive Placement of Pectus Bar Prepared by ASERNIP (overview and specialist advisor’s opinions)

NICE patient leaflet: Consent - procedures for which the benefits and risks are uncertain

Extract of paper prepared by ASERNIP-S

Interventional Procedure Overview of

Minimally Invasive Placement of Pectus Bar

Indication(s)

Pectus excavatum is the most common congenital deformity of the sternum

and anterior chest wall. It occurs in one in 1000 live births with male predominance ratio of 3:1.1 It is a progressive condition with the degree of

chest deformity worsening with the child’s growth and development. In most cases, patients with pectus excavatum are asymptomatic from a functional standpoint. However, in some cases, the cosmetic disfigurement is accompanied by restrictions in lung and/or heart development leading to a reduced cardiopulmonary function. Therefore, the primary indication for surgery is usually cosmetic but can include impaired cardiac function (typically mitral valve prolapse in 20-60% of cases), reduced pulmonary function or chest pain. Surgery typically takes place in mid to late childhood. While some argue that the benefit of pectus excavatum repair is mainly cosmetic, Coln et al,2 believe that lack of surgical correction in childhood leads to the development of cardiopulmonary symptoms or a worsening of existing symptoms in adulthood.

Summary of procedure

The Nuss technique is a procedure that involves elevating the sternum with

substernally placed metal bars to correct a pectus excavatum deformity. The

procedure is named after its originator, Donald Nuss, of the Children’s Hospital of the King’s Daughters in Norfolk, Virginia, USA. The first details of the technique were published in the Journal of Pediatric Surgery in 1998.3 With the patient in the supine position, the left and right intercostal spaces where the bar will be inserted are identified and marked. These marks on the pectus ridge correspond to the horizontal plane and mark the deepest point of the pectus deformity. The appropriate bar length is then measured from these markings. Before insertion, the bar is gradually bent to the optimal curvature that fits the individual patient's anterior chest wall dimensions.

In terms of surgical approach, two transverse 2-centimetre skin incisions are

made on the right and the left side of the mid-axillary line at the level of the markings. Subcutaneous tunnelling is undertaken between these two incisions

to allow transverse placement of a substernal convex steel bar, firstly with the

convexity facing posteriorly. Once inserted, the bar is then rotated so the convexity faces anteriorly using a Lorenz pectus bar rotational instrument

known as a "bar flipper" (Walter Lorenz Surgical, Jacksonville Florida, USA).

Either one or two of these bars are inserted in this manner. Recent modifications to the technique include the use of lateral stabilisers which limit movement of the main pectus bar(s) and thoracoscopy which provides visualisation of the pleural cavity, lung, and mediastinal structures to optimize bar placement and minimise surrounding tissue injury. Hebra et al,4 have developed a further modification which involves additional suturing to provide a ‘three point fixation’ of the pectus bar. The bars are removed as an elective procedure, usually within two years postoperatively.

Standard Intervention

The standard open ‘Ravitch’ procedure involves subperichondrial resection of

abnormal costal cartilages, transverse osteotomy and internal fixation of the

sternum. The corrected anterior sternal position may or may not be temporarily supported with a substernal bar.

Proposed Advantages

As the Nuss procedure involves only two anterior chest wall incisions, raising

pectoralis muscle flaps, resection of rib cartilages, or performing a sternal osteotomy as per the conventional open procedure are no longer necessary.

This leads to a much shorter operating time and decreased blood loss, incidence of sternal fracturing and length of hospital stay.5 An earlier return to full activity may also be possible after the Nuss procedure because the stability and strength of the chest wall are not compromised.

One of the most severe complications associated with the open Ravitch procedure is thoracic dystrophy resulting in severe restrictive lung disease.

The impaired chest wall growth that occurs with this complication has been

attributed to injury of the costochrondral junctions and sternal growth centre

during the surgery.6 With the Nuss procedure, such a complication is no longer a consideration because there are no required resections or incisions made to ribs or cartilage.

Specialist advisor’s opinion / advisors’ opinions

Specialist advice was sought from the Society of Cardiothoracic Surgeons of

Great Britain and Ireland, British Association of Paediatric Surgeons

The specialist opinion stated that the minimally invasive aspect of the

procedure is considered ‘definitely novel’. The procedure has been performed

for many years as an open technique: for about a decade in the US but only

within the last 3 years in the UK. The relatively slow uptake in the UK is due to

uncertainty regarding:

• The perceived requirement of thoracoscopic guidance during the

procedure to minimise damage to surrounding structures

• The current uncertainty as to the long-term outcome following the Nuss

procedure

It was estimated that less than 10% of UK surgeons would be presently

performing this procedure and then, in only a few specialised centres.

The potential impact of the procedure on the NHS was considered ‘moderate’.

A comment was made that the procedure itself was not common and that the

number of eligible patients would not change in the foreseeable future.

However, uptake will increase with more awareness of the operation as it is

‘much more appealing than the open method’.

The specialists also outlined several costs. There is an initial outlay of

equipment (approx £7000) and the ongoing cost of the bars (£500). They also

pointed out that operative time would also be shorter compared to the open

procedure which would reduce overall costs.

In terms of safety and efficacy, the specialists were aware of only one

recorded case of life threatening injury (cardiac injury). They also provided

some complications data (no references provided):

Pneumothorax (2.6%)
Low risk of infection (0.7%)
Low risk of cardiac injury
Potential for metal bar to become displaced (5-6%)
Other issues were also noted:
Both open and closed methods are painful, requiring epidural anaesthesia.
There is no known effect on thoracic development but theoretically this
should not be a problem.
Risk of relapse after the supporting bar is removed with the Nuss procedure. Currently bar removal occurs about 2 years post-op. ‘Longterm outcome reports are favourable”.

Issues for consideration by IPAC

The specialists had provided unreferenced data for three potential

complications: pneumothorax, infection and bar displacement. The following

table outlines the specialist cited rates followed by the range of rates cited in

the current literature.

Specialist Cited Data Range Cited in Literature

Pneumothorax 2.6% 2.6% - 40%

Infection 0.7% 1.2% - 5.6%

Bar Displacement* 5%-6% 0% to 29.9%**

* defined differently across the studies

** the use of lateral stabiliser bars, thorascopy and other differences in Nuss

technique vary across these studies

Actor’s Brief

The actor should be given:

Instructions for the candidate
The NICE Interventional Procedure Guidance 3 for ‘Minimally invasive placement of pectus bar’

Instructions given to candidate:

Scenario

Candidate’s task:

Your task is to:

Check the parent’s understanding about why the procedure is done and what it involves
Explain the role of NICE when new procedures are developed
Explain the risks and benefits of open and minimally invasive procedures, including the complications
Ensure the parent understands issues of consent and why the procedure is part of a research or audit study.

To help candidate prepare the briefing pack contains:

The NICE Interventional Procedure Guidance 3 for ‘Minimally invasive placement of pectus bar
Interventional Procedure Overview of Minimally Invasive Placement of Pectus Bar Prepared by ASERNIP (overview and specialist advisor’s opinions)
NICE patient leaflet: Consent - procedures for which the benefits and risks are uncertain

Additional Information for the Actor

You are the parent of a 9 year old son. Your child has a congenital deformity called Pectus excavatum or funnel chest. The lower part of the sternum is displaced inwards and the lower ribs are prominent. Your child’s condition is not causing any problems with the heart or breathing, but your child is teased at school and is very self-conscious.

The child’s paediatrician has recommended correction of the condition using a new ‘Nuss procedure’ which is minimally invasive, instead of the routine open surgical method, known as the Ravitch procedure. The surgeon has said that the new procedure is not normally available and special permission will be required from the Primary Care Trust. This has alarmed you and, although you want to follow the surgeon’s advice, you want to understand why it is not normally available. You have written to the Chief Executive of the Primary Care Trust to ask to discuss it.

Actor’s task:

During the meeting you need to ask the following:

What is the difference between the old and new procedure?
Is the new procedure not normally available because of cost?
What are the risks of the new procedure?
The paediatrician mentioned something about an increased risk of pneumothorax – what is this and how great is the risk?

Examiner’s Brief

The examiner should be given:

Instructions for the candidate
The NICE Interventional Procedure Guidance 3 for ‘Minimally invasive placement of pectus bar
Interventional Procedure Overview of Minimally Invasive Placement of Pectus Bar (Prepared by ASERNIP)
NICE patient leaflet: Consent - procedures for which the benefits and risks are uncertain

Instructions given to candidate:

Scenario

Candidate’s task:

Your task is to:

Check the parent’s understanding about why the procedure is done and what it involves
Explain the role of NICE when new procedures are developed
Explain the risks and benefits of open and minimally invasive procedures, including the complications
Ensure the parent understands issues of consent and why the procedure is part of a research or audit study.

To help candidate prepare the briefing pack contains:

The NICE Interventional Procedure Guidance 3 for ‘Minimally invasive placement of pectus bar
Interventional Procedure Overview of Minimally Invasive Placement of Pectus Bar Prepared by ASERNIP (overview and specialist advisor’s opinions)
NICE patient leaflet: Consent - procedures for which the benefits and risks are uncertain
Marking Guide

Excellent / Good / Satisfactory / Bare Fail / Clear fail
1.Communication skills

Opens and closes discussion appropriately
Explains jargon
Appropriate amount of information presented at the right pace

2. Communication skills (explaining appropriately key public health concepts)

Explains the procedure and risks/benefits

3. Communication skills (listening and ascertaining key information)

Listens to the parent’s concerns
Listens to the parent’s questions

4. Demonstrating ascertainment of key public health points from the material provided and uses it appropriately

Clearly explains the role of NICE and decision-making
Explains that new procedures with uncertain risks and benefits are recommended to be performed with appropriate consent/audit/research
Explains that cost is not an issue in this situation, but is considered by NICE

5. Appropriately and sensitively handles uncertainty or conflict and responds appropriately to challenging questions

Balances the risks and benefits of the procedure, given the cosmetic reason for the procedure.
May suggest further discussion with the surgeon to clarify uncertainty

Total

Extract of paper prepared by ASERNIP-S

Interventional Procedure Overview of

Minimally Invasive Placement of Pectus Bar

Indication(s)

Pectus excavatum is the most common congenital deformity of the sternum

and anterior chest wall. It occurs in one in 1000 live births with male predominance ratio of 3:1.1 It is a progressive condition with the degree of

Summary of procedure

The Nuss technique is a procedure that involves elevating the sternum with

substernally placed metal bars to correct a pectus excavatum deformity. The

In terms of surgical approach, two transverse 2-centimetre skin incisions are

made on the right and the left side of the mid-axillary line at the level of the markings. Subcutaneous tunnelling is undertaken between these two incisions

to allow transverse placement of a substernal convex steel bar, firstly with the

convexity facing posteriorly. Once inserted, the bar is then rotated so the convexity faces anteriorly using a Lorenz pectus bar rotational instrument