Review of Lodox Statscan in the detection of peripheral skeletal fractures in multiple injury patients

Patients and methods 

Consecutive charts of 245 consecutive polytrauma patients aged 16 years or more (Injury Severity Score (ISS) >16), who underwent LS imaging in our emergency department, a European level I trauma centre, were retrospectively analysed. Patient demographics and injury data were abstracted from our electronic trauma registry.4

The radiological objective consisted of the preliminary diagnostic summary concerning peripheral osseous injuries, recorded electronically by the attending emergency physician (unit policy) and the definitive diagnosis of the attending radiologist. The results of LS images were reviewed and compared with additional radiological imaging (plain radiographs, computed tomography (CT)) performed to assist with further management of bone injuries. Additional plain radiographs (Philips Optimus-Buckydiagnostic, Hamburg, Germany) were done when requested by the attending physician or the orthopaedic surgeon. CT scans using a 16-slice multidetector row-CT system (Sensation 16, Siemens, Forchheim, Germany) were performed when indicated, for intra-articular and comminuted fractures. We recorded each case where the diagnostic protocol was altered resulting in additional X-rays and compared the clinical impact of the two modalities.

Statistical analysis of sensitivity, specificity and positive and negative predictive value (PPV and NPV) of LS versus further radiography (conventional X-ray or CT) was performed by a consultant statistician, including 95% confidence intervals for all calculations.

Results 

A mean ISS of 20 (range 16–86) was calculated for our 245 consecutive trauma patients (172 men and 73 women) aged between 16 and 93 years (mean 44.5 years).4

Peripheral bone injuries 

Limbs (excluding hands and feet) 

Forty-two patients showed injuries of the shoulder girdle. LS demonstrated 72% sensitivity and 100% specificity in the detection of shoulder lesions (Table 1). Most missed fractures were non-surgically treated lesions of the scapula or non-dislocated fractured clavicles. Ten patients (24%) required surgical stabilisation.

Table 1. Detection of upper limb injuries.

	Parameter	Shoulder		Upper arm		Forearm		Hand
		Estimate	95% CI	Estimate	95% CI	Estimate	95% CI	Estimate	95% CI
	Sensitivity (%)	72	54–89	90	59–100	64	39–91	55	16–84
	Specificity (%)	100	98–100	100	98–100	100	98–100	100	98–100
	PPV (%)	100	86–100	100	69–100	100	66–100	100	40–100
	NPV (%)	95	91–98	100	97–100	98	95–99	98	95–99

Ten patients with distal humerus and 14 with radius and ulna fractures were ruled out. The device detected with 90% sensitivity and 100% specificity distal humerus fractures (Table 1). On the other hand, for forearm fractures (radius and ulnar shaft fractures as well as distal radius and ulnar fractures), the sensitivity dropped to 64%, while specificity was 100% (Table 1). Nineteen patients with distal humerus and forearm fractures (79%) required surgery.

Femur fractures occurred in 24 patients. Lodox demonstrated 88% sensitivity and 100% specificity in the detection of femoral fractures (Table 2). As many as 14 patients suffered tibia/fibula fractures. LS values for sensitivity and specificity dropped to 80% and 100%, respectively, for those fractures (Table 2). In general, for femoral and tibial/fibular fractures, surgical treatment was necessary in 33 patients (87%).

Table 2. Detection of lower limb injuries.

	Parameter	Thigh		Calf		Foot
		Estimate	95% CI	Estimate	95% CI	Estimate	95% CI
	Sensitivity (%)	88	78–98	80	55–98	45	14–79
	Specificity (%)	100	97–100	100	97–100	100	98–100
	PPV (%)	100	93–100	100	72–100	100	40–100
	NPV (%)	95	90–98	95	91–97	98	95–99

Hands and feet 

Hand and foot fractures occurred in eight and nine patients, respectively. LS demonstrated 55% sensitivity and 100% specificity in the detection of hand fractures (Table 1). The values for sensitivity and specificity dropped to 45% and 100%, respectively, for foot fractures (Table 2). Seven patients (88%) with hand injuries and all nine patients (100%) with foot injuries required surgery.

An overall sensitivity and specificity of 81% and 100%, respectively, was reached for all fractures of the upper and lower limbs, excluding hands and feet. Including these last two topographical areas sensitivity dropped to 73%.

Discussion 

Our results demonstrated that Lodox detected upper and lower limb injuries with sensitivity and specificity of 73% and 100%, respectively. Wei et al., in a systemic analysis of peripheral missed injuries in emergency radiology using conventional AP and lateral X-rays, reported an overall percentage of 3.7% for missed extremities fractures. A total of 23.1% of those injuries were radiographically imperceptible lesions of the foot (7.6%), elbow (6.0%), hand (5.4%) and wrist (4.1%).10 In our study, we performed a Lodox AP total body scan for the detection of skeletal injuries. Although the performance of a single fast AP plane scan presented good results in detecting injuries of the long bones (81% sensitivity), detection of fractures of the small bones of the hand and foot was not so successful. One explanation might be the fact that the Swiss Electro Medical Systems (EMS) use vacuum mattresses instead of long spine boards on which alignment and positioning of a patient is much easier compared with the body-adapting mattresses.

Including these last two topographic areas, our findings have led to a drop of the sensitivity to 73%. The performance of a second localised lateral scan on these two regions can improve our sensitivity values with minimum time loss and radiation exposure. The most frequently missed skeletal injuries of the upper and lower limbs were lesions of the hands (45%) and feet (55%), such as carpal and tarsal bone fractures and distal forearm fractures (36%). Similar results have been reported by other studies on missed injuries with conventional X-rays.10, 11

Additional plain radiographs were carried out for: (1) superior focussing and more precise resolution of the affected part of the body (Fig. 1(a)–(c)), (2) additional second or third plane, (3) additional information about fracture type and planning of the surgical approach and (4) for preoperative planning of implant size and positioning on calibrated digitised films. Most frequently, additional plain radiographs were requested by the treating orthopaedic surgeon to assist with further management of injuries of the upper and lower limbs (69% of all cases). A total of 31% of the additional plain radiographs were ordered because the attending emergency physician required further clarification, for example, where local tenderness or swelling was present. Other reasons for additional radiographs were poor quality of the LS image (<2%) and incomplete capture of the fracture zone in the LS image, usually of hand or foot fractures (7%) (Table 3) (Fig. 2(a)–(c)).

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Fig. 1. Anteroposterior Lodox scan of a polytrauma patient showing a left distal femur fracture and a left midshaft tibial fracture (a). Anteroposterior and lateral plain radiograph of the comminuted fracture of the distal femoral metaphysis with intra-articular extension of the fracture line (b) (AO Type 33 C2). This patient also had a CT of the knee (not shown) for superior estimation of the comminuted distal femur metaphysic and femoral condyles and for preoperative planning of implants and surgical approach. Anteroposterior and lateral plain radiograph of the tibial diaphyseal fracture (c) (AO Type 42 B2).

Table 3. Etiology of additional radiological procedures per anatomical region.

	Anatomical region	Additional X-rays+CTs	Out of screen	Not seen	Bad quality	Superior focussing, additional plane, preoperative planning
		Requested by	Attending emergency physician: 31%			Orthopaedic surgeon: 69%
	Shoulder girdle	43	0	14	0	29
	Humerus	10	0	1	0	9
	Forearm	17	2	4	0	11
	Hand	10	3	1	2	4
	Thigh	18	0	1	0	17
	Calf	12	0	3	0	9
	Foot	11	3	2	1	5
	Total	121 (100%)	8 (7%)	26 (<22%)	3 (<3%)	84 (69%)

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Fig. 2. (a) Anteroposterior Lodox scan of a polytrauma patient. The right upper limb as well as the left upper limb distally to the level of the elbow is not included in Lodox's picture. Apart from the obvious left distal femoral (AO Type 33 C3) and tibial fractures (AO Type 43 C3), a possible dislocation of the left elbow joint can be suspected due to the peculiar alignment of the humerus with the proximal ulna. (b) Lateral digital X-ray demonstrating left elbow dislocation. (c) Anteroposterior X-ray demonstrating fractures of IIIrd, IVth and Vth metacarpal bones.

Additional CT scans were taken for intra-articular and comminuted fractures only.7 Orthopaedic surgeons routinely request CT scans to assess and classify intra-articular fractures of the upper and lower limbs, that is, of the elbow, wrist, knee and ankle. However, they are used to evaluating the following based on plain radiographs: preoperative planning of implant size and positioning, comparison of preoperative dislocation and postoperative reduction and three-dimensional appraisal of specific features of fractures. In diaphyseal fractures of the upper and lower limbs, digitised plain radiographs allow measurement of the bone's intramedullary diameter for nail sizing and measurement of the length of broken and intact bone for plate sizing and positioning.9 It is very likely that CT imaging reduced the number of additional plain radiographs as many clinically suspected fractures were ruled out, or were detected but did not require additional plain radiographs. As a beneficial effect of CT imaging, early CT scans other than head, thorax, abdomen and pelvis may be taken in haemodynamically stable patients that is, for intra-articular fractures.

Limitations 

The performance of conventional imaging according to established clinical criteria (plain radiography and CT as current gold standards) plus Lodox scanning on all patients would have been a more appropriate methodology. However, our concern has been that, since Lodox represents a Food and Drug Administration (FDA)-approved and established diagnostic device, the comparison of Lodox versus conventional radiographs would have been difficult because our ethical committee would not have allowed both imaging techniques in the same patient.

Conclusion 

The new ‘Lodox Statscan’ (LS) digital low-radiation imaging device is a valuable adjunct in the emergency department that allows rapid detection of bone injuries in polytrauma patients, significantly reducing the median whole-body scanning time and the overall radiation dose.3, 8 Additional radiological imaging for peripheral skeletal injuries was required in 50% of cases reviewed. Only 31% of additional X-rays were requested by the emergency medicine physician. In 69% of the cases, additional imaging was requested by the orthopaedic surgeon on duty. The number of additional radiographs would probably be greater if our patients had not performed routine CT scans for intra-articular and comminuted fractures.

Our results for peripheral skeletal injuries demonstrate that LS, although extremely useful as a diagnostic tool in the emergency department, was not as effective as in spinal, truncal and pelvic injuries. Lodox should therefore be interpreted with caution when actual management decisions are made. Future engineering should anticipate this problem to further reduce extra imaging and radiation and to develop Lodox Statscan as a truly all-in-one diagnostic tool.

Conflict of interest statement 

The authors declare that they have no conflict of interests.