Current concepts in rib fracture fixation

Introduction

Rib fractures are common following blunt thoracic trauma. Simple rib fractures are managed conservatively with analgesia and physiotherapy. However, between 6% and 15% of patients who sustain blunt thoracic trauma have a flail segment or multiple rib fractures.¹ These patients commonly develop respiratory failure due to inadequate ventilation secondary to mechanical failure and pain. This group are also associated with a high mortality rate and prolonged mechanical ventilation.^1-3

A flail chest is at the more severe end of the spectrum and is defined as the fracture of three or more consecutive ribs at multiple sites, resulting in paradoxical chest wall movement.^1-3 Patients presenting with a flail chest associated with other injuries carry a high mortality risk, and, as would be expected, respiratory compromise clouds decision-making in the polytrauma setting.

Management of flail chest and multiple rib fractures

Historically, management for rib fractures including flail chest and multiple rib fractures is conservative, consisting of analgesia, ventilatory support and pulmonary hygiene.⁴ Several methods of operative fixation have been described since the 1950s. Other non-surgical techniques are described to stabilise the thoracic cage by means of external traction, in order to restore normal breathing mechanics.⁵ These early interventions were experimental at best, and despite initial interest they failed to gain enough to obtain entry into the surgical subconscious.

Non-surgical techniques to manage flail chest which have been described in the past include external traction using adhesive tape or towel clips (Fig. 1), internal pneumatic stabilisation (Fig. 2) and patient positioning. However, all are associated with complications such as prolonged bed rest, pressure ulcers, protracted mechanical ventilation, secondary chest infections and persistently high mortality rates.⁵ In addition, some patients treated non-operatively report a high rate of painful fracture nonunion or symptomatic chest wall deformity.⁵

Fig. 1

Rudimentary chest wall traction.¹⁹

Reproduced from the U.S. Army Medical Department Office of Medical History (http://history.amedd.army.mil/booksdocs/wwii/thoracicsurgeryvolII/chapter1figure4b.jpg). Commercial publication incorporates United States Government works (17 USC 403).

Fig. 2

Drinker respirator or ‘iron lung’. The negative pressure ventilation was thought to help with reduction of the chest wall.

Image reproduced without copyright restriction, from the Centers for Disease Control and Prevention (http://phil.cdc.gov/phil/details.asp?pid=6536). Content provider: CDC/ GHO/ Mary Hilpertshauser. Credit: Jim Gathany.

Moving on from these early attempts, a range of internal fixation options have been popularised with almost every option from locked internal plates through to intramedullary splints and ‘Judet’ style plates. A range of randomised and other studies have been reported to support the use of the newer evolution of rib stabilisation devices. The outcomes of these studies demonstrate that operative fixation of the flail chest is associated with improved outcomes such as reduced duration of mechanical ventilation (DMV), intensive care unit length of stay (ICULOS), hospital length of stay (HLOS), mortality rate and incidence of pneumonia. To date, the majority of publications to support this are cohort or case-control studies.^6-16 Only three randomised controlled trials (RCT) are reported in the literature (Tables I and II).^17-19

Marasco et al¹⁷ conducted an RCT of 40 patients with traumatic flail chest, which reported a significantly shorter ICULOS (p = 0.03), DMV (p = 0.01) and a reduced rate of tracheostomy (p = 0.04) in 20 patients with operative rib fixation using Stryker (Kalamazoo, Michigan) Inion OTPS resorbable plates.

Granetzny et al¹⁸ randomised 40 patients with flail chest into two groups: non-operative and operative. The non-operative group was treated with an adhesive plaster splint and mechanical ventilation. The operative group was treated with surgical fixation between 24 and 36 hours after admission. Operative fixation was achieved using stainless steel wire fixation with or without intramedullary Kirschner wires (K-wires). Their results showed reduced duration of mechanical ventilation (two vs 12 days p < 0.001), intensive care unit length of stay (9.6 vs 14.6 days p < 0.001), hospital length of stay (11.7 vs 23.1 days p < 0.001) and incidence of chest infection (10% vs 50% p < 0.014).¹⁸

Tanaka et al²⁰ have also reported their own randomised controlled trial and demonstrated improved outcomes with operative fixation of flail chest in their randomised controlled trial of 37 patients (18 of whom were treated operatively). Surgical stabilisation was achieved using Judet struts within 14 days of injury. Their results showed reduced DMV (10.8 vs 18.3 days p < 0.05), ICULOS (16.5 vs 26.8 days p < 0.05), incidence of pneumonia at 21 days (22% vs 90% p < 0.05), rate of tracheostomy and better recovery in lung function at three months as shown by spirometry.²⁰

While these studies were sufficient for the National Institute for Health and Care Excellence (NICE) to recommend surgical stabilisation of the chest wall for patients with a flail chest, they certainly leave a lot to be desired in terms of numbers. A recent meta-analysis21 by our group has shown that operative fixation is favoured for the majority of end points; however, there is certainly scope for more research on this new and evolving treatment.

The literature as it stands supports the use of stabilisation; however there are a range of unanswered questions, particularly surrounding the operative technique and selection of those patients who are suitable for surgery.

Indications for fixation

The indications for rib fracture fixation are not well established. A number of indications have been proposed including presence of a flail segment, inadequate analgesia or failure of conservative management (development of respiratory failure) associated with multiple rib fractures, chest wall deformity, chronic symptomatic nonunion and thoracotomy for other indications.^22-23

Chest wall deformity

Direct crush injury to the thorax can result in deformity of the thoracic cage and a resultant loss of thoracic volume. Severe displacement may also damage underlying lung parenchyma or other structures. Rib fracture fixation in this group of patients aims both to restore thoracic volume and prevent further damage.^22,23 Patients benefitting from this approach are small in number. However, in the severely damaged chest wall (Fig. 3 a-c) at presentation, and in patients who go on to develop significant volume compromise secondarily, there is clearly a benefit to chest wall stabilisation (Fig. 4).

Fig. 3

a) Initial radiograph showing right-sided flail chest on admission; b) Radiograph taken two days later showing secondary collapse and loss of volume; c) Cross-sectional CT scan on admission demonstrating posterior fractures and a flail chest.

Fig. 4

The patient shown in Fig. 3 following stabilisation of the chest wall.

Techniques and surgical approaches

Both plain radiography and a CT scan of the chest are essential for the diagnosis and pre-operative planning of rib fracture fixation. When available, 3D volume rendering of the CT images can be helpful.^22,23

Several surgical approaches have been described in the literature. These include posterolateral thoracotomy, muscle-sparing thoracotomy, the axillary approach and the inframammary approach with pectoralis lifting.²⁶ When planning the approach, it is key to understand the position of the fractures from the imaging, paying particular attention to accessing both fractures of each rib in a flail segment. It is not always enough to fix only the more easily accessed anterior fractures as this will not restore the function and volume of the thorax. That said, it is not necessary to stabilise all of the fractures, and often fixing alternate ribs will be sufficient to stabilise the flail and restore continuity and function of the chest wall.

Deciding which ribs need fixing is a combination of weighing up the fracture pattern, associated lung contusion, parenchymal lacerations, and likely stability of the fracture. Typically, the fourth rib is the highest accessible rib for plate fixation. It is possible to access the third rib posteriorly, though intramedullary fixation may be easier to achieve in practice. The eighth rib is usually the lowest which commonly needs to be stabilised, and it is extremely rare for there to be an indication to attempt fixation of the floating ribs (the 11th and 12th in most people). A careful plan of operative approach is required, usually with the aid of axial or volume-rendered CT scans to establish the fracture configuration and best surgical access. Even when using muscle-sparing approaches, access to the chest wall causes some surgical trauma, and in addition adds to the stress response. Judicious fixation of selected ribs can achieve a stable chest wall.

Posterolateral thoracotomy and muscle-sparing thoracotomy (Fig. 5) are performed in the lateral decubitus position, with the ipsilateral arm on a prop above the head to bring the scapula superiorly and anteriorly onto the chest wall. Both of these approaches provide good access to anterior, lateral and posterior rib fractures. The axillary approach provides access to anterior and anterolateral fractures, whereas the inframammary approach provides access to far anterior and superior fractures.²⁶

Fig. 5

Surgical approach to the ribs. a) Extensile incision for lower para-trapezius approach; b) Muscle plane between trapezius and latissimus dorsi; c) Serratus anterior visible between the plane; d) Rib fracture identified; e) Locking plate in situ stabilising the ribs.

For fixation with plates or Judet struts, a wide field of access is required. Posterior fractures can be fixed using an intramedullary splint allowing for a relatively minimal approach, thereby lessening the amount of soft-tissue dissection required, or directly via a paraspinal approach.^19,22,23,26

Rib fracture fixation should be performed by an experienced surgical team capable of performing a thoracotomy, repairing underlying pleura or parenchyma if necessary, and able to deal with any complications which may arise. Most commonly in the UK the operation is performed by orthopaedic surgeons, cardiothoracic surgeons or both in combination.

Implants

The earliest surgical techniques for rib fracture fixation involved intramedullary K-wires and heavy sutures, but these techniques were associated with implant failure, hardware migration and rotational instability. Non-locking plate fixation was also used in the past, but due to cyclic thoracic wall movement during respiration, there was a high rate of screw loosening and hardware failure. Implants have since been developed specifically for rib fracture fixation.^19,22,23,26

Future direction

Current literature and guidance from NICE support rib fracture fixation in carefully selected patients. The guidance note from NICE states, “Current evidence on insertion of metal rib reinforcements to stabilise a flail chest wall is limited in quantity but consistently shows efficacy. In addition, there are no major safety concerns in the context of patients who have had severe trauma with impaired pulmonary function”.³²

The literature is lacking in Level I evidence, with no large, well-designed randomised controlled trials to support the results and investigate the various aspects of rib fracture fixation including indications, timing of surgery, approach, implant choice and cost implications. There are several randomised controlled trials (NCT02094807, NCT01367951, NCT02132416, NCT01147471) currently underway,³³ and their results are eagerly awaited.